review of extraction eqpts

SOLVENT EXTRACTION EQUIPMENT EVALUATION STUDY PART 1. REVIEW OF THE LITERATURE

R. G. ~eier,'~) Compiler

L. M. Browne, Report Coordinator

January 1977

BATTELLE Pacific Northwest Laboratories Richland, Was hi ngton 99352

(a) Atlantic Richfield Hanford Company, Richland, WA

ABSTRACT

Th is i s P a r t 1 o f a th ree -pa r t document t h a t reviews the so lvent ex t rac-

t i o n contactors a v a i l a b l e f o r use i n radiochemical reprocessing p lan ts . The

th ree pa r t s are: P a r t 1 - A Review o f the L i t e r a t u r e , P a r t 2 - Workshop Pro-

ceedings, P a r t 3 - A Summary. The main o b j e c t i v e of t he document i s t o p rov ide

an in format ion base t o a i d i n contac tor s e l e c t i o n and design of f u tu re repro-

cessing p lan ts .

The L i t e r a t u r e Review ( P a r t 1 ) br ings together sca t te red data on a l l major

contac tors i n use today. I t conta ins an annotated b ib l i og raphy o f the c i t a -

t i o n s used i n the rev iew and a complete l i s t i n g of a l l t he c i t a t i o n s screened

p r i o r t o t he review. These b ib l i og raph ies should a i d i n determin ing which

repo r t s would be most use fu l i f a d d i t i o n a l i n fo rma t ion i s desired.

The Workshop Proceedings (Pa r t 2) summarizes a workshop on the t i t l e

sub jec t he ld i n mid-1976. The p a r t i c i p a n t s had considerable experience i n

t he use o f so l ven t e x t r a c t i o n contac tors i n reprocessing p lan ts . The purpose

o f t he workshop was t o b r i n g together these people i n o rder t o c o l l e c t , evalu-

a t e and document any in fo rmat ion t h a t would be he lp fu l i n t he s e l e c t i o n of

so lvent e x t r a c t i o n contac tors f o r nuc lear fue ls reprocessing p lan ts .

The Summary (Pa r t 3 ) i s a compendium o f the i n fo rma t ion presented i n t h e

L i t e r a t u r e Review and the Workshop Proceedings. I t was w r i t t e n t o present

t he s a l i e n t p o i n t s o f Par ts 1 and 2 w i thou t going i n t o as much d e t a i l . The

Summary conta ins a l i s t i n g o f t he references used i n the L i t e r a t u r e Review

so the reader can e i t h e r go d i r e c t l y t o t h e c i t a t i o n o r t o Par ts 1 and 2

f o r f u r t h e r in fo rmat ion .

CONTENTS

. . . . . . . . . . . . . . . . . . . LIST OF TABLES

. . . . . . . . . . . . . . . . . . 1.0 INTRODUCTION

. . . . . . . . . . . . . . . . . . 2.0 PULSECOLUMNS

2.1 DESIGN OF INTERNALS . . . . . . . . . . . . . . 2.1.1 R e d o x p l a n t . . . . . . . . . . . . . .

. . . . . . . . . . . . . 2.1.2 Uranium Recovery

. . . . . . . . . . . . . . 2.1.3 Purex P l a n t

2.1.4 Purex Flowsheet . Carbon T e t r a c h l o r i d e D i 1 uen t . . . . . . . . . . . . . . . .

. . . . . . . . . . . 2.1.5 E f f e c t s o f Temperature

2.1.6 Coalescence . . . . . . . . . . . . . . 2.1.7 E f f i c i e n c y C a l c u l a t i o n s . . . . . . . . . .

2.2 PULSE GENERATORS . . . . . . . . . . . . . . . 2.2.1 D e s c r i p t i o n of Types . . . . . . . . . . . 2.2.2 Ai r-Dri ven Pulse Generators . . . . . . . . .

2.3 CONCATENATED PULSE COLUMNS . . . . . . . . . . . . 2.3.1 Packaged E x t r a c t i o n . P a r t i t i o n - S t r i p

. . . . . . . . . . . . . . . . Column

2.3.2 Uses of Check Valves . . . . . . . . . . .

2.4.1 Types o f Back-Mixing . . . . . . . . . . . 2.5 THEORETICAL CONSIDERATIONS . . . . . . . . . . . . .

2.5.1 E f f e c t o f Opera t ing Parameters on HTU . . . . . . . . . . . . T e f l o n P l a t e C a r t r i d g e

2.5.2 E f f e c t o f Design Parameters on HTU . . . . . . . . . S t a i n l e s s S tee l P l a t e C a r t r i d g e

2.5.3 E f f ec t s of Design and Opera t ing Va r i ab les . . . . . . . . . . . on Column E f f i c i e n c y

2.5.4 Column Capaci ty and E f f i c i e n c y as a Func t ion o f Dispersed Phase Holdup . . . . . . . . . .

2.5.5 Ef fect o f Opera t ing Parameters on HTU . S i n g l e P l a t e Column . . . . . , . . . . . a

CONTENTS (contd)

2.5.6 E f f e c t o f Drop V e l o c i t y and Pulse Condi t ions on Drop S ize . . . . . . . . . . . . . .

2.5.7 E f f e c t s of Operat ing and Design Parameters on F l oodi ng Capacity and Eff i c i ency . . . . . . .

2.5.8 Operat ing Var iables A f f e c t i n g HTU . . . . . . . 2.5.9 E f f e c t o f Operat ing and Design Var iab les on

Flooding Capacity and E f f i c i e n c y . . . . . . . . . . . . 2.5.10 E f f e c t o f Operat ing Var iab les on Holdup

2.5.11 A Review o f Previous Flooding Cor re la t i ons . . . . 2.5.12 L o n g i t u d i m l Mix ing o f t he Continuous Phase . . . . 2.5.13 E f f e c t o f Operat ing and Design Parameters on

. . . . . . . . . . . . Column Throughput

2.5.14 Flooding D e f i n i t i o n . . . . . . . . . . . . 2.5.15 Dispersed-Phase Hold-up C o r r e l a t i o n . . . . . . 2.5.16 Dispersed . Phase Holdup C o r r e l a t i o n . . . . . . 2.5.17 Parameters Important t o E x t r a c t i o n E f f i c i e n c y . . .

2.6 VALVE ACTUATED PULSE COLUMN . . . . . . . . . . . 2.7 PHASE REDISTRIBUTION . . . . . . . . . . . . . .

. . . . . . . . . 2.8 AUTOMATIC CONTROL OF A PULSE COLUMN

2.9 REVIEWPAPERS . . . . . . . . . . . . . . . . 2.10 OTHER PULSE COLUMN APPLICATIONS AND GESIGNS . . . . . .

2.10.1 Pulse Column f o r Removal o f Hafnium from . . . . . . . . . . . . . . . Z i rconium

2.10.2 Ro ta t i ng Paddle E x t r a c t i o n Column . . . . . . 2.10.3 Pulse Column f o r Processing STR and

. . . . . . . . . . . . . . S I R Fuels

. . . . . 2.10.4 Pulse Columns . General Observations

2.10.5 Column f o r Recovery o f Uranium from D i l u t e Waste Sol u ti ons . . . . . . . . . . . .

2.10.6 E f f e c t s o f Operat ing and Design Var iab les on Pulse Columns . . . . . . . . . . . .

2.10.7 Column Capacity i n a Radiochemical P lan t . . . . 2.90.8 Removal o f Thorium from Uranium i n t h e

. . . . . . . . . . . . . Scrub Sect ion

CONTENTS (contd)

2.10.9 Eurochemic Pulse Column Battery . . . . . . . 2.10.10 Eurochemic Pulse Column Operating

. . . . . . . . . . . . Character is t ics

. . . . . . 2.10.11 Re-extraction of Uranium from TBP

. . . . . . . . . . . . . . . . . 3.0 MIXER-SETTLERS

3.1 SAVANNAH RIVER CONTACTORS . . . . . . . . . . . . 3.1.1 Mixing Capabi l i t ies . . . . . . . . . . . . 3.1.2 Hydraulic Character is t ics of Mixer-Settler

Impellers . . . . . . . . . . . . . . . 3.1.3 Operating Character is t ics . Three-Stage

Mixer S e t t l e r . . . . . . . . . . . . . . 3.1.4 Cr i t i c a l ly-Safe Mixer S e t t l e r . . . . . . . . 3.1.5 Mixing Efficiency in a Three-Stage Mixer

S e t t l e r . . . . . . . . . . . . . . . . 3.1.6 Mixer Devices . Pump-Mix Mixer-Settler . . . . .

. . . . 3.2 OTHER MIXER-SETTLER USED FOR RADIOACTIVE SERVICE

3.2.1 KAPLType . . . . . . . . . . . . . . . 3.3 THE EFFECT OF ENTRAINMENT . . . . . . . . . . . .

. . . . . . . . . . . 3.4 SOLVENT EXTRACTION ECONOMICS

. . . 3.5 DESIGN CONSIDERATIONS FOR MIXER-SETTLERS EXTRACTORS

3.5.1 Mixer-Settler Design Parameters . . . . . . . . 3.5.2 Review of Mixer-Settler Design . . . . . . . .

. . . . . . . . 3.5.3 Additional Mixer-Settler Types

4.0 CENTRIFUGAL CONTACTORS . . . . . . . . . . . . . . . 4.1 SAVANNAH RIVER DEVELOPMENT . . . . . . . . . . . .

4.1.1 Centrifugal Contactor Performance . . . . . . . 4.1.2 Centrifugal Contactor Performance .

16 Stage Unit . . . . . . . . . . . . . . 4.1.3 Centrifugal Contactor Performance .

Five-Stage U n i t . . . . . . . . . . . . . 4.1.4 Centrifugal Contactor Capacity Tests . . . . . . 4.1.5 Centrifugal Contactor Performance .

. . . . . . . . . . . . . . 18-Stage Uni t

CONTENTS (con t d )

. . . . . . . 4.2 ARGONNE NATIONAL LABORATORY DEVELOPMENT

. . . . . . . 4.2.1 Long Ro to r C e n t r i f u g a l Contac to r

4.2.2 C e n t r i f u g a l Contac to r t o Operate i n t h e Annular M i x i n g Mode . . . . . . . . . . .

4.3 MULTISTAGE CENTRIFUGAL CONTACTORS . . . . . . . . . 4.4 MISCELLANEOUS CENTRIFUGAL CONTACTOR

DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . 4.4.1 Cen t r i f uga l Contac to r Overview

4.4.2 Feed and Discharge Method . . . . . . . . . 4.4.3 Quadronic C e n t r i f u g e . . . . . . . . . . .

. . . . . . . . . . . . 4.4.4 Pressure Balance

. . . . . . . . . . 4.4.5 Podb ie l n i ak E x t r a c t o r s

5.0 MISCELLANEOUS CONTACTORS . . . . . . . . . . . . . . 5.1 COMPARTMENTED. AGITATED COLUMN . . . . . . . . . . 5.2 PERFORATED PLATE CONTACTOR . . . . . . . . . . . 5.3 COMPARISON OF EXTRACTION COLUMN PACKING . . . . . . . 5.4 PACKEDCOLUMNHOLDUP . . . . . . . . . . . . . . 5.5 COLUMN WITH HORIZONTAL TUBULAR JETS . . . . . . . . 5.6 PULSEDROTATINGDISCCONTACTOR . . . . . . . . . .

6.0 COMPARISON OF CONTACTORS . . . . . . . . . . . . . . 6 - 1 OPERATION, MAINTENANCE AND DESIGN

. . . . . . . . . . . . . . . CONSIDERATIONS

6.1.1 Packed Columns. Pulse Columns. M ixe r S e t t l e r s and C e n t r i f u g a l Contac to rs . . . . . . . . .

6.2 OPERATION AND MAINTENANCE . PULSE COLUMNS VERSUS . . . . . . . . . . . . . . . MIXERSETTLERS

6.3 EFFICIENCY AND CAPACITY STUDIES . PACKED COLUMNS. . . . . . . . . . . . . . . PULSED AND UNPULSED

6.4 HEAD ROOM VERSUS FLOOR AREA COMPARISON . MIXER SETTLERS VERSUS PULSE COLUMNS . . . . . . . . . .

6.5 CONTACTOR EFFECTIVENESS . . . . . . . . . . . . 6.5.1 Size-Capaci ty R e l a t i o n s h i p . . . . . . . . . 6.5.2 Contac to r A d a p t a b i l i t y . . . . . . . . . .

v i i

CONTENTS (contd)

6.6 DECONTAMINATION PARTITIONING AND WASTE LOSSES - ,. I

1 - 1 MIXERSETTLERS VERSUS PULSE COLUMNS . . . . . . . . . 6-10 I

. . . . . . . . 6.7 DESCRIPTION OF A VARIETY OF CONTACTORS 6-11 . - I 6.8 OVERVIEW - SOLVENT EXTRACTION CONTACTORS . 6-11 I .. 1 6.9 EFFICIENCY, ENERGY INPUT, HOLD-UP TIME, AND I

OPERATING RANGE - MECHANICAL INPUT COLUMN I

VERSUS MIXER SETTLERS. . . . . . . . . . 6-11 I I

6.10 ADVANTAGES AND DISADVANTAGES - MIXER SETTLERS, I

I

PACKED COLUMNS, PULSED COLUMNS AND I

. . . . . . . . . . . • CENTRIFUGALEXTRACTORS. 6-12 I I

6.11 GENERALIZED COMPARISON - MIXER SETTLERS, PACKED I

. . . . . . . . COLUMNS AND PERFORATED PLATE COLUMNS 6-13 1 6.12 THE EFFECTS OF AXIAL DISPERSION ON COLUMNAR-TYPE I

. . . . . . . . . . . . . . . . CONTACTORS. 6-13 I I

6.13 COMPARISON OF OPERATING AND DESIGN VARIABLES AND COST - MIXER SETTLERS PULSE COLUMN AND CENTRIFUGAL

. . . . . . . . . . . . . . . . . CONTACTOR 6-1 4 6.14 COMPARISON OF RESIDENCE TIME - MIXER SETTLERS, PULSE

. . . . . . . . . COLUMNS AND CENTRIFUGAL CONTACTORS 6-14

7.0 ANNOTATED BIBLIOGRAPHY FOR THE LITERATURE REVIEW OF . . . . . . . . . . . . SOLVENT EXTRACTION CONTACTORS. 7-1

8.0 LISTING OF ALL THE CITATIONS SCREENED FOR THE . . . . . . . . . . . . . . . . LITERATURE REVIEW. 8-1

. . . . APPENDIX A - Unpublished Data Used in the Literature Review A-1

DISTRIBUTION . . . . . . . . - . . . . . . . . . . . Distr-1

LIST OF TABLES

. . . . . . . Uranium Recovery Pulse Column Spec i f i ca t ions 2-3

. . . . . . Uranium Recovery Operat ing and Design Var iables 2-4

Purex P l a n t Pulse Column S p e c i f i c a t i o n s . . 2-5

Pulse Column Operat ing Condit ions f o r Purex P l a n t Columns . . . . . . . . . . . . . . . . . 2-6

. . . . . . . . Purex P l a n t Pulse Column Car t r i dge Design 2-6

Ef fect o f Design Var iab les on Pulse Column Performance . . . . . . . . . . . . . . . . . . 2-7

Mixed P l a t e Car t r i dge Geometry . . . . . . . . . . . . 2-8

Purex 2A Column Flooding Frequencies . . . . . . . . . 2-11

. . Nozzle P l a t e Car t r i dge Design Purex P l a n t 2-12

. . . . . . Mixed P l a t e Car t r i dge f o r Purex P l a n t I B X Column 2-13

Operat ing C h a r a c t e r i s t i c s o f t he I B X Column Mixed P l a t e Car t r i dge . . . . . . . . . . . . . . . . . 2-13

Pulse Column Nozzle P l a t e Car t r i dge and Spec i f i ca t i ons f o r Use w i t h Zirconium Conta in ing Feed . . 2-14

D ispers ion and Coalescence Times f o r E x t r a c t i o n Volumn Operat ion . . . . . . . . . . . . . . . . 2-17

Dimension of Organic I n t e r p l a t e Packing . . 2-18

Comparison of Column Performance.. Conventional Versus Packing Types Suggested by Koski . . . . . . . . . . 2?18

Average Leakage Rates Past t he P is ton . . . . . . . . . 2-26

Column Con f igu ra t i on and Operat ing Condi t ions . . 2-32

Summary of Back-Mixing Runs . . . . . . . . . . . . 2-34

. . . . . . . . . . . . . . . . . . HTU Values 2-37

System Used i n S w i f t ' s C o r r e l a t i o n . . . . . . . . . . 2-38

Range of Var iab les Studied . . . . . . . . . . . . . 2-40

Car t r i dge Desc r ip t i on . . . . . . . . . . . . . . . 2-41

Range o f Var iables Used by B a i l l i e . Smoot and Babb . . . . . . . . . . . . . . . . . . and Thornton 2-49

Net Exponents Used by B a i l l i e . . . . . . . . . . . . 2-50

. . . . . . . . . . Nomenclature f o r Ryons Connotat ion 2-52

. . . . . . . . . . . . . . . . P l a t e Design Data 2-57

LIST OF TABLES (contd)

26 Purex 1A Column and 1 C Column Rotating Paddle Tests . . 2-61

. . . . . . . . . . . . . . . . . . . 27 HTU Values 2-62

. . . . . . . . . . . . . . 28 Pertinent Column Features 2-65

. . . . . . . . . . . . . . . 29 de Witte Observations 2-66 . . . . . . . . . . . . . . . . 30 Cavendish Results 2-67

Relationship a t an Impeller Speed of 345 rpm . 3-2

Impeller Efficiency Tests . . . . . . . . . . . . . . 3-4 . . . . . . . . . . . . . . . . Transfer Efficiency 3-8

. . . . . . . . . . . . Resul t s of Cal cul a t i onal Method 3-12

Total Annual Cost of Extracting a Solute from a . . . . . . . . . . . . . . . . . . Feed Solution 3-14

Comparison of Twelve Industrial Mixer-Settler Designs . 3-16 . . . . . . . . . . . . . . . . Stage Efficiencies 3-21

Relationship Between Rotor Speed. Capacity and . . . . . . . . . . . . Aqueous-to-Organic Flow Ratio 4-1

Centrifugal Contactor Feeds . 2 4 4 ~ m Separation . . 4-5

. . . . . . . . Adjustments for Varying Feed Compositions 4-13 The Effect of Rotor Speed on Waste Loss .

. . . . . . . . . . . . . . . Podbielniak Extractor 4-14

Comparison of Typical Results of High Capacity Extraction Towers Using the System Methyl Isobutyl Ketone. Water

. . . . . . . . . . . . . . . . . and Acetic Acid 5-2

. . . . . . . . . . Tests Performed i n 4.in . Dia Column 5-4 . . . . . . Values of Constants in Johnson's Holdup Equation 5-6

Comparison of Liquid-Liquid Extraction Contactor Types . . 6-2 Comparison of Pulse Columns and Mixer-Settlers .

. . . . . . . . The Effect on Operability and Maintenance 6-5

. . . . . . . . . . . Contactors for Radioactive Service 6-7

~ d m ~ a r i s o n of Contactors for the System Acetic Acid . . . . . . . . . . . . . Methyl isobutylKetone-Water 6.9

Pulse Column Versus Mixer S e t t l e r Comparison . . . . . . . . . . . . . . . . . . Purex Process 6-10

1.0 INTRODUCTION

LITERATURE REVIEW - SOLVENT EXTRACTION CONTACTORS

1.0 INTRODUCTION

This r e p o r t reviews the a v a i l a b l e l i t e r a t u r e on the types o f l i q u i d -

l i q u i d e x t r a c t i o n contac tors and a u x i l i a r i e s t h a t have been used t o perform

radiochemical separat ions. The document b r i e f l y descr ibes work which has

been done i n the f i e l d o f pu lse columns, mixer and s e t t l e r , and c e n t r i f u g a l

contac tor technology as they are r e l a t e d t o radiochemical so l ven t e x t r a c t i o n

processing. Also inc luded a re comparisons between the types o f contactors

and desc r ip t i ons o f miscel laneous so l ven t e x t r a c t i o n contac tors which have

n o t y e t been used f o r radiochemical processing. Each summary b r i e f l y

describes t h e equipment t h a t was tested, t he chemical systems used t o t e s t

t he equipment, and the r e s u l t s o f the tes ts . The i n d i v i d u a l reviews deal

w i t h on l y t he s a l i e n t p o i n t s developed i n the o r i g i n a l papers and con ta in

the o r i g i n a l , unal tered, conclus ions drawn by the authors o f each paper.

Add i t i ona l i n fo rma t ion on radiochemical so l ven t e x t r a c t i o n contac tors

may be found i n Sect ion 8 (Supplementary Reference L i s t ) .

2.0 PULSE COLUMNS

2.0 PULSE COLUMNS

A pulse column i s a ver t ical counter-current contacting device containing a ser ies of stationary plates or packing. An up-and-down pulsing motion i s superi.mposed on the net counter-current flow of the l iquid phase. In addition to providing intimate mixing of the two phases, t h i s pulsing action also provides a means fo r the counter-current to flow through the plate per-

forations or packing in ters t ices .

The principal emphasis of t h i s section i s the selection of pulse column internals fo r radiochemical separations. However, the sa l i en t features of

-pulse generators and phase redistribution devices a re also described. Theo-

re t ica l correlations of pulse column variables, (e.g. , pulse frequency, pul se amp1 i tude, and sieve pl a t e charac ter i s t ics ) have been addressed as well as the phenomenon of backmixing. Papers describing several non-nuclear

applications of pulse columns have also been summarized.

2.1 DESIGN OF INTERNALS

A wide variety of internal pulse column designs have been studied for

several nuclear separations processes. These designs and processes a re summarized in the fol lowing subsections.

2.1.1 Redox Plant

Burns (24) conducted t e s t s t o define the physical character is t ics of a pulse coTumn and to determine the f eas ib i l i t y of using a pulse column for the f i r s t extraction cycle service i n the Redox process. The feed

near the center of the Redox f i r s t cycle column contains 2 molar (M) uranium and %0.2 - M n i t r i c acid. The scrub stream fed a t the top i s 1 .8 M aluminum n i t r a t e nonanhydrate 0.2 - M def icient i n n i t r i c acid, and the extractant fed a t the bottom i s methyl isobutyl ketone containing 0.2 M n i t r i c acid.

Burns reached the following conclusions:

2 Stage heights of about 7 i n . a t throughputs i n excess of 1500 g a l / f t /hr were obtained. Thus, a required column height of about 10 f t i s computed fo r the 15 stages needed i n f i r s t cycle Redox column i f the column - ._ diameter scale-up factor i s ignored.

Plates can be made of 18- to 22-gauge s ta in less s tee l perforated plate. The optimum hole s ize will vary w i t h the physical charac ter i s t ics of the system and hole diameters from 0.033 to 0.050 i n . were found t o be adequate for Redox. The larger holes allowed greater throughputs b u t

resulted in s l igh t ly larger H E T S ' ~ ) values. The number of holes per 2 plate had l i t t l e e f fec t on HETS from 75 to 400 holes/in. .

Plate spacing studies showed lower HETS values f o r closer plate spacing over the range of 1 to 4 in.

Pulse frequency and displacement studies showed tha t f o r most plate

designs, and a t 1 i n . plate spacing, the optimum pulse frequency was about 50 cyc lesh in w i t h a pulse displacement of about 1/2 in. Larger plate spacing warranted higher frequencies.

Interface location studies showed tha t i n the Redox IA column, where

the mass t ransfer i s from aqueous t o organic, the interface location a t the top (aqueous continuous) gives the lowest HETS. In the IC

column where the t ransfer i s from organic to aqueous, the location of

the interface has only a s l igh t e f fec t on HETS.

Observations on the e f fec t of plate wetting charac ter i s t ics indicated tha t i t i s desirable to have the plates wetted by the continuous phase. In the Redox f i r s t cycle column the HETS was doubled by dri-filming the plates which resulted in an organic interface.

No sens i t iv i ty t o phase volume ra t ios was obtained. Operability was

'demonstrated fo r phase ra t ios of o / A ( ~ ) from 1/3 to 3/1. As these f

l imits were approached there was no evidence of f a i lu re .

( a ) Height equivalent to a theoretical stage

( b ) Organic phase flow divided by aqueous phase flow.

Appreciable amounts o f a i r i n t he pu lse column d i d n o t a f f e c t i t s

performance o r i t s e f f i c i e n c y .

2.1.. 2 Urani um Recovery

Process eva lua t i on i n 3-, 5-, 8-, and 16-in. diameter columns showed

t h a t :

1 ) H T U ( ~ ) values a re 1/3 t o 1/2 o f those obta ined i n packed columns,

2) throughput p r i o r t o f l o o d i n g was about t he same as packed columns,

and

3 ) an increase i n HTU value i s 100% f o r an e x t r a c t i o n column and 35%

f o r a s t r i p p i n g column when column diameter increased from 3 t o 20 i n .

and 3 t o 30 in . , r espec t i ve l y .

The data obta ined from t h i s eva lua t i on r e s u l t e d i n the s p e c i f i c a t i o n s

g iven i n Table 1 f o r the e x t r a c t i o n columns t o be used i n the TBP process.

I n t h i s process 30 volume percent ( ~ 0 1 % ) TBP i s the ex t rac tan t , u rany l

n i t r a t e i s t he feed, and d i l u t e n i t r i c a c i d i s t h e scrub stream.

TABLE 1. Urani um Recovery Pulse Column Spec i f i ca t i ons

Location

Column Diameter, in.

Height of Plate Section, f t

Scrub Extraction Strip

Pulse amplitude, in. Pulse frequency, cyclmin Plate spacing, in. Hole s ize , in. Free area, %

Estimated HTU, f t

Extraction

20

Strippinq

30

(a ) Height o f a t r a n s f e r u n i t

The effects of operating and design variables found by Stevenson (105) are l i s t ed in Table 2.

TABLE 2. Uranium Recovery Operating and Design Variables

Variable Re1 ative Importance General Effect

Pulse amplitude and fre- First-order effect on Increases in the amplitude- quency (or the product both extraction and frequency product up to of the numerical values capacity; HTU decrease 70 in./min cause reductions of the ampl i tude and the twofold as af increased in HTU values; the capacity frequency ) from 20 to 70 in./min. ranges from zero through a

maximum and back to?cr$ as the ampl i tude frequency product i s increased from zero.

Hole diameter First-order effect on 1/8-in. diam holes give capacity ; second-order good a1 1 -around performance. effect on extraction ( in HTU and capacity increase the range 0.04 to with hole s ize in the range 3/16-in; diam). from 0.04 to 3/16-in. diam.

Percent f ree (perforated) Second-order effects on HTU and flooding capacity area of the plates both extraction and increase with increase in

capacity in the range free area. 10 to 40% free area.

Plate spacing Second-order in the HTU and flooding capacity range 1 to 4 in. increase in plate spacing.

Flow rates/unit cross- Second-order effect on Extraction performance good sectional area of the extraction. u p to 50% of flooding capa- co 1 umn c i ty ; HTU generally increases

with flow rate above 50% of the f 1 oodi ng capaci ty.

Chemical f l owsheet Third-order for changes in the TBP-Process flowsheet; TBP-system HTUs are about twice those for the Redox system.

Pl astic-faced plates Thi rd-order. The best performance of stainless steel plates i s comparable to the best of plastic-faced plates.

Wall clearance between Third-order for clearance The 1/8-in. diametral clearance plates and column wall up to 1/8 in. on the reduced extraction efficiency

diameter in the 3-in. compared to 0.02-in. diam column. diametral clearance.

Temperature Third-order effect on The difference in HTU values extraction when the was not significant. temperature i s increased from 77 to llO°F.

2.1.3 Purex Plant

Numerous studies have been conducted deal ing with Purex Process Plant Pulse Columns. The most pertinent of these are discussed in the following subsections.

Pulse Column Battery - 16 Ton Uranium/Day Plant A comprehensive treatise by Nicholson (81 '82) describes the dimensions,

pulsing condition, and column internals for a Purex solvent extraction plant having a nominal capacity of 16 ton of uranium/day; see Table 3. The

TABLE 3. Purex Plant Pulse Column Specifications

Plate (or packed) Section Over-a1 1 ,-, Internal

Column Height, f t ta' Diameter, in . Height, f t

HA, 1 A , 2D 33 24(b) . 1 3 . 5 ( ~ ) 3 2 ( ~ ) 1 3 . 5 ( ~ )

H C , lC, 2E 27 34 18 I B X 3 3 27 28

( a ) From bottom surface of bottom disengaging s e c t i o n to top surface o f top disengaging s e c t i o n .

( b ) Extraction ( c ) Scrub

plant columns were designed to require only two sizes of fi~ed~amplitude, variable-frequency pulse generators in order to simplify maintenance and replacement problems. The pulse conditions for the various columns are

listed in Table 4.

TABLE 4. Pulse Co lumn Operating Conditions for Purex Plant Columns

Pu lse Cond i t i ons Displacerne_nt Ampl i tude, Frequency.

Col umn v o l . , i n . 3 in . cyc ies /min

HA, l A , 20 485 1 .l (a)0.6(b) 35 t o 110

HC, lC, 2E, 10, 20 485 0.53 35 t o 110

(a ) E x t r a c t i o n (b) Scrub

The sieve plate geometry, plate spacing, and other sa l ien t de ta i l s

of the cartridges specif ic for the various Purex solvent extraction columns are summarized in Table 5. The ef fec ts of these design variables on pulse

column performance are l i s t ed i n Table 6. All of the t e s t data obtained on

a 3- t o 27-in. diameter column are included.

TABLE 5. Purex Plant Pulse Column Cartridge Design

Plate ~ e o m e t r y ' ~ ) Hole O i am Freew Area, Nozzle P la te

Co 1 umn i n . Depth, i n . Spacinq, in .

HA, l A , 0.125 23 -- 2

HC, l C , 2E. I 0.1875 23 -- 10.20

0 .'I 25 10 0.05 10 ~ x t r a c t i o n ( ~ ) 0.125 23 -- 2

10 0.125 2 3 -- 10.1875 33 --

28 0.125 23 -- 2 2A 1 - in . f l llorothene Rascdig r ings

(a) Holes t o be spaced equ id is tant on t r iangu lar centers.

(b) Four l o ~ ~ v e r p la tes , 13% f ree area, located 14, 26, 80, and 120 i n . below top p la te i n ex t rac t i on sect ion and three louver plates, 16% f ree area, located a t the bottom and 70 and 128 i n . above the bottom p la te i n the scrub section.

(c ) Six louver plates, 16.5% f ree area, located a t 4 - f t in terva ls .

(d) Six louverplates, 20% f ree area, located 14, 36, 60, 84, 108, and 132 in . below the top plate.

TABLE 6. E f f e c t o f Design V a r i a b l e s on Pu lse Column Performance

Var iab le Range Studied Re1 a t i ve Importance General E f f e c t

Col umn Diameter Essen t i a l l y no e f f e c t on Processing capac i ty va r ies 3 t o 24 i n . f l ood ing vo l umn ve loc i t y ; d i r e c t l y w i t h the column

t h i r d -o rde r e f f e c t on cross-sect iona l area from e f f i c iency , p rov id ing 0.5 f t 2 t o 5.0 f t 2 ; s l i g h t adequate interphase mix- decrease i n e f f i c i e n c y w i t h i n g i s a t ta ined . increas ing diameter f rom 3 i n

t o 24 i n . f o r A-type columns.

Car t r idge Height Thi rd-order e f f e c t on Less than 10% decrease i n 6 t o 13 ft capac i ty and HTU. capac i t y by inc reas ing the

con tac to r 1 ength 50%; increase i n con tac to r 1 ength from 9 t o 13 f t increased the HTU an average o f 10%.

Hole Diameter Second-orderef fec t on* An increase i n capac i ty and HTU 0.06 t o capac i ty and e f f i c i ency . w i t h inc reas ing ho le diameter; 0.188 i n . a ho le diameter o f 0.125 i n .

appears t o be near optimum f o r most co l umns .

P la te Free Area F i r s t -o rder e f f e c t on The capac i ty and HTU genera l l y 10 t o 23% both capac i t y and increases 10% o r more when the

e f f i c i e n c y . f r e e area i s increased from 10 t o 23%.

P la te Spacing Second-order e f f ec t on General increase i n both capac- 1.0 t o 4.0 i n . capac i ty and e f f i c i e n c y i t y and HTU w i t h increased . i n the range o f 1 t o 4 spacing.

in..

P l a t e Mate r ia l F i r s t - o rde r e f fec t on Capacity o f C-type column w i t h capaci ty, second order f l uorothene o r nozzle p la tes i s e f f ec t on e f f i c i e n c y o f about 700% greater than t h a t C-type columns. w i t h s t a i n l ess s tee l s ieve

p l a tes ; e f f i c i e n c y o f C-type co l urnns w i t h nozzle p la tes i s 20 t o 50% h igher than w i t h f luorothene sieve p la tes.

D i ametral Clearance Thi rd-order e f f e c t on (Column I D l e ss capac i ty f o r a clearance P la te Diameter) up t o 118 i n . on a Up t o 0.125 i n . 3.00-in. diameter c o l -

umn ; t h i rd-order e f f e c t on e f f i c i e n c y f o r a column w i t h aqueous phase cont inuous ; second-order e f f e c t on e f f i c i e n c y w i t h organic phase continuous.

Very s l i g h t increase i n capac- i t y and HTU w i t h increas ing clearance up t o 118 i n . f o r aqueous phase continuous ; considerable increase i n HTU w i t h increas ing clearance w i t h organic phase con t i nuous .

Organic-Phase Continuous Extraction Column

The object ive of Hessons (58) work was t o define the ca r t r idges capable

of permitting organic-phase continuous operation i n a compound extract ion-

scrub column. The bes t ca r t r idge f o r the ext ract ion section-proved t o be

one containing 23% f r e e area nozzle p la tes w i t h 0.05-in. long nozzles point-

ing downward. A t a pulse amplitude of 1.0 in, HTU values of between 0.6

and 1.0 f t were obtained f o r pulse frequencies of 60 t o 100 cycles/min and 2 530 t o 1060 gallons per hour per square foot ( g a l / h r / f t ) .

The best Cartr idge f o r the scrub section consisted of a l t e r n a t e pa i r s

of s t a i n l e s s s t e e l and fluorothene p la tes ; the p la te cha r ac t e r i s t i c s a r e

l i s t e d in Table 7 . Using a pulse amplitude of 0.6 i n , flooding pulse f r e -

quencies were 125 and 105 cycles/min a t volume ve loc i t i e s of 240 and

480 g a l / h r / f t 2 , respecti vely. Efficiency, a s measured by chlor ide ion

t r an s f e r , showed HTU values of 2.9 and 1.2 f t a t the above volume ve loc i t i e s

I t was found t h a t when the s t a i n l e s s s t e e l p la tes were par t ly wet by the

organic phase, t h i s ca r t r idge eff ic iency was considerably reduced.

TABLE 7. Mixed P la te Cartridge Geometry

Free Area, Hole Diameter, Plate Spacing, % in. in.

Stainless Steel 21 0.08 1

Fluorothene 2 3 0.18 1

Since the object ive of Hessons work was t o obtain a l t e rna t e phase

inversions, some s tud ies were di rected toward aqueous and organic coalescing

media on an individual basis . With the controlled in te r face a t the bottom

of the scrub sec t ion , zones pers i s t en t in aqueous coalescence could be

achieved i n a number of ways:

groups of two o r more 1/16-in. th ick s t a i n l e s s s t e e l s ieve p la tes

having 23% f r e e area , 0.06-in. diameter holes, and 1-in. spacing,

groups of two or more 1/8-in. thick stainless steel sieve plates h a v i n g 23% free area, 0.125-in. diameter holes, and 1-in. spacing, stainless steel sieve plates having 23% free area and 0.125 in.

diameter holes with 20-mesh screen 114 in. below the plate, and

2 in. o r more of stainless steel Raschig rings. From the standpoint of capacity and tenacity of coalescence the best

aqueous coalescer proved t o be the f i r s t item. A consistent reinversion t o

organic phase continuous operat ion could n o t be obtained without the use

of plastic. Ziegler process polyethylene, polyethylene, and fluorothene were investigated for their coalescing abil i ty. While each produced the desired phase reinversion, the degree of coalescing abil i ty decreases in

the order 1 i sted.

Both the free area and hole diameter of the plastic sieve plates

influenced the coalescing abil i ty. Plates having 40% free area were

superior t o 23% free area plates. Li t t le difference was observed between

plates having 3/16- and 1/4-in. diameter holes, b u t b o t h were superior t o 1/8-in. diameter holes. Polyethylene coated stain1 ess steel plates were

also tested, b u t their organic coalescing abil i ty was poor. This was

attributed to the decrease in the hole diameter and free area caused by

the coating.

Influence of Operating and Design Variables

The influence of pulse column operating and design variables were

investigated by ~ e i e r . ( ~ ~ ) The results of his investigation are listed below.

Effect of Operating Variables

Within the range of stable operation HTU values decrease with an increase in amplitude frequency product. HTU values are relatively insensitive t o volume velocity.

HTU values are n o t sensitive t o flow ratio.

HTU values are higher a t the dilute end of the column. An increase in temperature generally increases capacity and

decreases HTU values.

The c a p a c i t y i s p r o p o r t i o n a l t o ( a s p e c i f i c g r a v i t y ) 0 ' 7 ( i n t e r f a c i a l

t e n s i ~ n ) ~ ' ~ and i n v e r s e l y p r o p o r t i o n a l t o (v i scos i t y ) ' . 3.

E f f e c t o f Design Va r i ab les

A pu l se ampl i tude equal t o one-hal f t h e p l a t e spac ing u s u a l l y g i ves

t h e bes t performance.

The p l a t e s should be wet ted by t h e cont inuous phase.

I n t h e v i c i n i t y o f t h e geometry o f t h e s tandard c a r t r i d g e (0.125-in.

d iameter ho les, 23% f r e e area, and 2 - in . p l a t e spac ing) , t w o f o l d

v a r i a t i o n s of th roughput o r HTU va lues a r e encountered as t he p l a t e

v a r i a b l e s change th ree- t o f o u r f o l d .

The HTU values g e n e r a l l y i nc rease w i t h i n c r e a s i n g column he igh t .

I nc reas ing column d iameter inc reases channe l ing and, t h e r e f o r e , t h e

HTU values.

- Optimum HTU values a r e ob ta i ned w i t h a semiso ida l p u l s e wave shape.

F luore thene p l a t e s o r nozz le p l a t e s g i v e b e t t e r performance i n a

s t r i p p i n g column than a s i e v e p l a t e .

A graded ( i . e. , mu1 ti spaced p l a t e ) c a r t r i d g e inc reases c a p a c i t y and

e l im ina tes l o c a l f l ood ing i n an e x t r a c t i o n column.

. With t h e o rgan i c phase cont inuous a nozz le p l a t e c a r t r i d g e (3 /16- in .

d iameter ho les, 23% f r e e area, 2- in . p l a t e spac ing) w i t h t h e nozz les

p o i n t e d down was e q u i v a l e n t t o a s tandard s i eve p l a t e c a r t r i d g e w i t h

t h e aqueous phase cont inuous.

P lu ton ium E x t r a c t i o n Column

~ e ~ f r i t ' ' ' ) conducted t e s t s i n a pu l se column f a b r i c a t e d from 6- in .

d iameter g l ass p i pe . The e x t r a c t i o n s e c t i o n cons i s ted of a 1 0 - f t h e i g h t

of 1 - i n . d iameter by 1 - in . h i g h Raschig r i n g s . An a d d i t i o n a l 2 f t of pack- i n g was l o c a t e d above t he aqueous phase f e e t p o i n t t o s imu la te a scrub

sec t i on . The f lowsheet used i n t h e s tudy i s :

2AFS Scrub 2.5 M HN03

2AX E x t r a c t a n t 30% TBP i n S h e l l E-2342

Sat i s fac to ry performance of the Purex Plant 2A column u p t o a plant capacity f a c to r of 3.5 appears t o be a ce r ta in ty . As shown in Table 8,

the column appears t o be operable a t even higher capac i t i e s . Since the flooding frequency a t a capacity f a c to r of 4 i s near the m i n i m u m frequency obtainable, some f l e x i b i l i t y wi l l be l o s t . S table operation under the above conditions a t a capacity of 4.5 was obtained without pulsing. The use of unheated feeds tended t o reduce capacity by about 10%.

TABLE 8. Purex 2A Column Flooding Frequencies ( a ~ b )

Flooding Frequency, Capacity Factor cycleslmin

1 7 0

2 45

(a) Purex Phase I1 Flowsheet w i t h heated feeds (2AFS = 50°C and 2AX = 35OC).

(b) Pulse Amplitude: 1.1 i n .

Effects of Design Variables

Jansen (63) t e s ted many pulse column car t r idges w i t h varying p l a t e spacing and f r ee area as well a s d i s c r e t e packed sect ions . As a r e s u l t

of these t e s t s , i t was found t h a t the ca r t r idge designs l i s t e d i n Table 9

could be used i n the Purex Plant .

. . Organic Phase Continuous S t r i p p i n g Column

~ i e r k s ' ~ ~ ) studied organic continuous s t r i p p i n g columns u s i n g modifi - cat ions of a basic ca r t r idge which consisted of:

p la tes - s t a i n l e s s s t e e l nozzles

. area - 23% hole s i z e - 3/16-in. diameter p la te spacing - 2 in. in top one-third, 4 i n . i n bottom two-thirds, and nozzles - 0.04 in . deep pointed upward.

TABLE 9. Nozzle Plate Cartridge Design - Purex Plant - Continuous

Columns Phase

HA Scrub Organic

HS Organic

1 BX Aqueous

1C. 2E Aqueous

2A Organic

Maximum Pulse Volume Amp. x Frequency

P la te Hole Free P la te Nozzles Ve loc i ty Volume Ve loc i ty Type Diarn.in. Area, % Spacinq, in . Point qal / h r / f t 2 in./min

Nozzle 0.13 6 3 Down 1800 21

Nozzle 0.125 10 2 Down 2300 30

Nozzle 0.188 23 4 UP 1300 35

Nozzle 0.188 23 ,(a) 4 ( b ) 2000 40

Nozzle 0.188 23 2 (') Down 2 ( d ) . Scrub 1000

Ext rac t ion > 2000 250

(a ) Top h a l f (b) Bottom h a l f ( c ) Scrub (d ) Ext rac t ion

I n the f i r s t modification (Cartridge A ) , 3/4 in. thick polyethylene plates

were spaced 7/16-in. below a s tainless s teel plate every 6 in. in the bot-

tom third of the column, every 9 in. in the middle th i rd , and every 12 in.

in the top third.

A second modification (Cartridge B ) was identical t o Cartridge A except

that the polyethylene plates were 5/32-in. thick. The capacity of

Cartridge B was 15 to 20% higher than Cartridge A. A t modest throughputs

the capacity of the two cartridges was about equal, however, a t high

throughputs, the capacity of Cartridge B was only 50% of that obtained

with Cartridge A. The organic holdup with Cartridge B was on the order

of 20% higher than with Cartridge A.

Modified Cartridge fo r Purex IBX Column

A modified cartridge proposed by Richardson (85) for use in the Purex

Plant IBX i s compared t o the existing plant column in Table 10 while a

comparison of the flooding thresholds of the two cartridges are given in

Table 11.

Richardson (85) found that the mixed-plate cartridge had a much

higher capacity and estimated i t s HTU value to be between 2 and 3 f t . When

operating a t maximum efficiency the dispersed phase kold-up was approxi-

mately 70%, measured in the midsection of the column.

TABLE 10. Mixed Plate Cartridge for Purex Plant IBX Column

Plant Cartridge Proposed Cartridge ( a )

Plates Stainless Steel Stainless Steel Free Area, % 33 23 Hole Size, in. 3/16 3/16 Plate Spacing, i n . 4 2 Redistri butor Plates - every 4 - every 4 Column Height, f t 19 19 Column Diameter, in. 3 3

-

(a) 23% free area fluorothene plates inserted a t intervals ranging from 8 i n . a t the bottom to 13 i n . a t the top.

TABLE 11. Operating Characteristics of the IBX Column Mixed Plate Cartridge

Plant Cartridge Proposed Cartridge

Volume Velocity, Pulse amp1 i tude Volume Velocity , Pulse amp1 i tude ~ a l / h r - f t 2 times frequency gal /hr-ft2 times frequency

Pul se Column Battery

A Purex pulse column battery with the character is t ics l i s t ed in

Table 12 was tested by Rjchardson (88) with additions of 1 "01% dibutyl

phosphate and 0.06 - M zirconium n i t r a t e to the feed. Operating pulse f re -

quencies of 110, 70 and 60 cycles/min were obtained for the extraction,

scrub, and s t r i p p i n g sect ions, respec t i ve l y . These frequencies are normal

f o r t he e x t r a c t i o n and scrub columns, b u t low f o r t he s t r i p p i n g column

a1 though they a re s t i l l i n the range o f experience.

TABLE 12. Pulse Column Nozzle P l a t e Car t r idge and Spec i f i ca t ions f o r Use w i t h Zirconium Conta in ing Feed

Ex tract:?n Scrub Stripping Col umn Column Column

Height, ft 21 18 16

Cartridge

Free Area, % 23 10 10

Hole Diameter, in. 3/16 1 /8 1 /8

Capacity

gal/hr/ft2 1200 1000 1600

(a) Feed introduced 12 ft fran bottom

Purex Flowsheet - Carbon Te t rach lo r i de D i l u e n t

Ten ta t i ve s p e c i f i c a t i o n s were developed f o r Purex pu lse columns capa-

b l e of processing 10 s h o r t tons of uranium per day w i t h a so l ven t conta in -

i n g 30% TBP i n carbon t e t r a c h l o r i d e . H i g h l i g h t s o f the s p e c i f i c a t i o n s

repor ted by Richardson (86) are:

cascade he igh t : 31 ft (1B column d i v i d e d i n t o a 1B Scrub and a 1B e x t r a c t i o n column

p l a t e sec t i on he igh ts : 12 f t (1A e x t r a c t i o n and 2D e x t r a c t i o n ) t o 27 f t 1B e x t r a c t i o n )

column diameters: 7.5 i n . (1B Scrub, 2A, and 2B) t o 27 i n . (1C)

pulse ampli tude: 0.94 t o 1.06 i n . ( f i x e d )

pulse frequency: 35 t o 110 ( v a r i a b l e )

pe r fo ra ted p la tes : "Standard c a r t r i d g e " ( IA , 1B, 20) ; s t a i n l e s s s t e e l , 0.06-in. holes, 21% f r e e area, 2- in. spacing ( I C Y 2A, 2B)

phase disengagement S u f f i c i e n t volume f o r 1 0-min. holdup t imes sect ions :

In the course of the study the following ranges of var iables were

investigated:

p la te section height: 8.5 t o 13.2 f t

column diameter: 3 t o 16 in.

p la te spacing: 1 t o 2 i n .

p l a te hole diameter: 0.026 t o 0.125 in.

diametral clearance 0.015 t o 0.125 i n . between p la tes and wall :

pulse amplitude: 0.5 t o 1.5 in.

pulse frequency: 35 t o 120 cycles/min

amplitude times f r e - 30 t o 108 in./min quency product:

The p la te materials t e s ted included s t a i n l e s s s t e e l , f luorothene,

and s t a i n l e s s s t e e l coated with a hydrophobic p l a s t i c (Kel-F NW-25). The general e f fec t s of the major var iables on HTU and capacity a re :

Column Diameter - Increasing the diameter from 3 t o 16 in. increased

the HTU 0 t o 30%.

Flow Rates - While r e l a t i ve ly insens i t ive t o changes in throughput

r a t e , there was a general trend toward increased HTU with increased

ra tes . Pulse Amplitude and Frequency - Capacities were increased 5 t o 45%

when the amplitude was increased from 0.5 . to 1 in . As a f i r s t approxi-

mation, the HTU varied as a function of the product of amplitude and

frequency. HTU decreased sharply as t h i s product was increased causing a change in dispersion from the i ne f f i c i en t mixer-se t t ler type of

operation t o the more e f f i c i e n t emulsion type operation. A f u r t he r increase in the amplitude-frequency product beyond t ha t required t o

produce emulsion type operation had l i t t l e addit ional e f f e c t on HTU.

Cartridge Geometry - Decreasing the hole s i z e from 0.125 t o 0.06 i n .

decreased the HTU 10 t o 50% while reducing the capacity about 30%.

Further reduction t o 0.026 in. decreased the capacity by 50 t o 75%

without f u r t he r improving HTU.

Plate Material - Fluorott-~ene plates , preferentially wet by the organic phase, gave HTU's thatwerecomparable t o s ta inless s teel plates, b u t

had less than half the capacity. Dual-face plates ( s ta in less s teel .- with the top coated with a hydrophobic p las t ic , Kel-F NW-25) increased

the capacity and widened the operable amplitude-frequency product range .- b u t gave no s ignif icant HTU improvement. Interface Position - HTU was greater with the interface a t the top of the column except for the case of dual-face plates in the 1C Column, where top interface operati on reduced the HTU about threefold. Diametral Clearance - Increasing the diametral clearance from 0.015 to 0.125 in. in the column increased the HTU by about 60% of the 1 C Column system. No adverse effect was noted fo r the 1 A Column system.

2.1.5 Effects of Temperature

In t e s t s using the uranium recovery flowsheet (organic phase 12.5 vol% TBP in AMSCO) Burger ) obtained several results:

A higher temperature led to a bet ter dispersion and coalescence, and thus permitted greater freedom of operation and a higher volume capacity . Large gains i n efficiency were obtained a t elevated temperature in a stripping column. Even though a higher temperature lowers the dis t r ibut ion coefficients fo r uranium extraction, the higher temperature produced greater e f f i - ciency and lower waste losses (probably due to more favorable kinet ics) .

Dispersion and coalescence times determined f o r extraction volume operation are l i s t ed in Table 13.

2.1 .6 Coalescence

A typical pulse column for extraction from an aqueous phase into an

organic phase contains perforated s ta in less s teel plates and can be operated (72) . - with the aqueous-phase continuous and the organic-phase dispersed. Koski

proposed packing judiciously chosen interplate spaces w i t h materials which are wet by the organic phase preferentially. In these packed spaces the

TABLE 13. Dispersion and Coalescence Times fo r Extraction Column Operation

Temperature, Oi spersi?n)

Coal escence Tlme, sec a Time, sec(b)

17 207 3 1 27 148 23

37 132 18

-

( a ) Defined as the time required t o disperse as droplets, an organic phase, throughout a fixed volume of aqueous phase.

( b ) Defined as the time required for a clean interface t o form after stirring is stopped.

two phases are separated. If the packing i s suff ic ient ly t i g h t , the organic phase becomes continuous and the aqueous becomes dispersed within the packed section. As the organic i s expelled from the packing by the pulse, i t again meets a continuous aqueous phase and i s dispersed in i t . T h u s , al ternation

of continuous and dispersed phases i s achieved.

Application of the organic-wet interplate packing t o a conventional column operated with aqueous phase continually improves contact efficiency through :

improved mixing of the dispersed (organic) phase, increased residence time of the dispersed (organic) phase,

increased ra te of drop formation and coalescence, increased interfacial area between phases, under some conditions, reflux of the dispersed (organic) phase, and increased contact time between phases.

Column s t a b i l i t y and capacity are improved fo r the following reasons: channeling and eddies are limited to the regions between packed sec- t ions, back-mixing of the continuous (aqueous) phase i s reduced or eliminated; back-mixing, as used here, refers t o the flow of a phase in a direction opposite to i t s normal flow in the column, a more even vertical dis t r ibut ion of the dispersed (organic) phase

occurs ,

dispersed phase (organic) drop size i s more uniform, the dispersed phase (organic) velocity i s more uniform, and

the continuous phase (aqueous)velocity i s more uniform.

The use of organic-wet interplate packing were tested i n columns (see Table 14 for the column dimensions). The results of Koski's tes ts are

l is ted in Table 15. I t i s apparent from Table 15 that extraction and

scrubbing efficiency as we1 1 as column capacity are markedly improved by the use of organi c-wet i nterpl ate packing.

TABLE 14. Dimension of Organic Interplate Packing

Dimension, Area i n .

Length of E x t r a c t i o n Sect ion 8

Length o f Scrub Sect ion 8

Column Diameter 0.23

P l a t e Spacing 0.25

P l a t e Hole Diameter 0.02

P l a t e Free Area 23%

TABLE 15. Comparison of Column Performance--C nventional Versus Packing Types Suggested by Koski ( 7 2 7

Conventional Column Packing Factor Being Aqueous

Performance Compared Continuous ,(a) A ( b )

E x t r a c t i o n Percent of 5 t o 12 0.24 - 0.27 E f f i c i ency So lu te i n

R a f f i n a t e

Scrubbing ( c ) 4.3 x 10 3 1.1 105

E f f i c i e n c y . ~ a p a c i t y ( d ) g a l / h r / f t 2 157 297

(a) A l t e r n a t e packed and unpacked zones. (b) Ser ies of two unpacked zones and one packed zone w i t h t h e th ree

p l a t e zone bounded by an organ ic and an aqueous wet p la te . ( c ) R a d i o a c t i v i t y i n feed per u n i t o f so lu te d i v i d e d by r a d i o a c t i v i t y

i n organ ic phase per u n i t of so lu te . (d) Volume f low r a t e (sum of both phases) are f lood ing.

Tests were a l s o made by ~ a m i l ton(56) t o determine the i n f l u e n c e o f

design and opera t ing va r iab les on l i q u i d coalescence i n pulsed columns.

The organ ic coalescence a t t a i n e d was charac ter ized by a coalescence index

ranging from 0 (no coalescence) t o 11 (complete coalescence) . Aqueous-Phase Continuous Operat ion

Maximum coalescence was obta ined i n a uranium-bearing system a t low

frequencies, h igh volume v e l o c i t i e s , low aqueous-to-organic f low r a t i o s ,

and a pulse ampli tude o f 0.6 i n . Th i s was obta ined us ing a l i n e a r po ly -

ethy lene s ieve p l a t e w i t h 30% ( o r g r e a t e r ) f ree area, 3/16-in. ( o r g r e a t e r )

ho le diameter, an extremely f l a t and rough p l a t e surface, sharp ho le edges,

nonuniform ho le spacing, and a th ickness equal t o the ho le diameter.

Organic-Phase Continuous Operat ion

General ly, systems which showed good coalescence i n an aqueous con-

t inuous column went i n t o a complete a l t e r n a t e cont inuous phase i n v e r s i o n

o r "zebra" emulsion forn lat ion w i t h a bottom i n t e r f a c e , r a t h e r than remain-

i n g organic cont inous ly . Mass t r a n s f e r augmented organic coalescence,

presumably because o f g r e a t l y increased i n t e r f a c i a l tens ion t o such an

ex ten t t h a t the column would remain organic continuous. This formed the

"zebra" emulsion o r a l t e r n a t e phase invers ions on ly a t very h igh aqueous-

to-organic f 1 ow r a t i o s a t f requencies very near f looding.

Complete a l t e r n a t e phase i n v e r s i o n was a f u n c t i o n o f t he aqueous we t t i ng

c h a r a c t e r i s t i c s o f the s t a i n l e s s s t e e l s ieve p l a t e s r a t h e r than o f the

organ ic coalescence caused by the p l a s t i c p la tes .

F looding Frequency Data

Considerable f l o o d i n g frequency data were accumulated i n t he course

o f the work s ince t h e f i n a l coalescence observat ions were made a t i n c i p i e n t

f 1 ooding cond i t ions . I t was found t h a t i nc reas ing aqueous-to-organic r a t i o

decreased capac i ty and t h a t changing from top i n t e r f a c e t o bottom i n t e r f a c e

decreased the capaci ty . General ly, cond i t i ons lead ing t o good coalescence

( b e t t e r e x t r a c t i o n e f f i c i e n c y ) reduced capaci ty .

Plastic-Coated Plates

Stainless s teel sieve plates tha t were dispersion-coated or whirlclad (coated in a fluiridzed bed of solid p las t ic granules) w i t h o u t fur ther treatment showed infer ior coalescing character is t ics compared to sol i d p las t ic :- plates. However, i f the holes were dr i l led out to sharp edges and the two plate surfaces were made as f l a t as the solid plates, coalescence identical to that of solid p las t ic plates was obtained.

2.1.7 Efficiency Cal cul ations

The method used for calculating the height equivalent to a theoretical stage (HETS), the height of a transfer-unit (HTU), overall stage efficiency ( E o ) , and average Murphree stage efficiency ( E M ) i s described by Bruns. (17)

'

A brief summary of calculation procedures fo l l ow.

Calculation A - Pulse Column, Simple A-Type Extraction Section

1. Determine m y uranium dis tr ibut ion ra t io . Use HN03 N and s a l t

NO3 - N from aqueous eff luent stream analysis or from feed ma ke-UD records.

AFS 2. Calculate L/V, aqueous to organic volume flow ra t io , (AFF'S i n case of s p l i t feed) , from r u n data. AX

3 . Determine P . P = L / V m .

4. Determine M. M = 'fs - 'x m 'w - m

where = conc. U N H in g l a , in aqueous influent stream, Xfs AFS (AFF'S in case of s p l i t feed) ,

Y x = conc. U N H i n g/e in organic influent stream, AX,

Yw = conc. U N H in g/e in aqueous eff luent stream, AW, and

m = uranium dis tr ibut ion ra t io .

- 5. Calculate N S . N S - log [ ( M ) ( 1 - P ) + P I log 1 / P

6. Calculate N t . Now, - - 2.3 log [ ( M ) (1 - P ) + P 1 1 - P

*Now i s the number of overall aqueous-film transfer units.

Plate-section height, Z.

where n = number of plates in the cartridge,

1 = distance between plates, face t o face, in . , and t = thickness of plates, in.

8. HETS = Pl ate-secti on height N s

- Plate-section height 9. HTU - t

Calculation B - Pulse Column, C-Type Stripping Column

1 . Determine operating line.

Y = L/V ( X - X x ) + Yw

where CX L / V = aqueous-to-organix flow rat io, g

X x = conc. U N H g / a in aqueous influent stream, C X , and

Yw = conc. U N H g /e in organic effluent stream, CW.

2. Plot operating line on proper equilibrium diagram. 3. Determine equilibrium l ine, assuming 90% of the HN03 in the

influent organic stream, C F , i s transferred from organic t o aqueous in the f i r s t stage. The remainder i s assumed t o trans- fe r in the next stage. If the extractant has more HNO3 than 90%

of the CF HN03, then assume the HN03 concentration in the aqueous phase a t the beginning of stage two i s approximately equal t o the CX HN03 concentration.

4. Sketch in theoretical stages, NS.

5. Determine N t by graphically solving the following integral:

where

Noo = Nt based on t h e o v e r a l l o r g a n i c - f i l m c o n t r o l l i n g ,

Y f = conc. UNH g/e i n i n f l u e n t organic stream, CF,

Yw = conc. UNH g/e i n e f f l uen t organic stream, CW, and

Y - Y* = d r i v i n g f o r c e f o r any corresponding value o f X .

6. Ca l cu la te HETS and HTU s i m i l a r t o p a r t s 7 and 8 o f c a l c u l a t i o n

procedure.

Ca l cu la t i on C - M i x e r - S e t t l e r Ex t rac to r , A-Type

1. Determine m y L/V, P, and Ns s i m i l a r t o C a l c u l a t i o n A.

2. Ca lcu la te o v e r a l l e f f i c i e n c y , Eo.

Eo = NS/Actual number o f stages.

3. Ca lcu la t i on average Murphree stage e f f i c i e n c y .

where

EMA = t h e average Murphree aqueous phase stage e f f i c i ency .

C a l c u l a t i o n D - M i x e r - S e t t l e r Ex t rac to r , C-Type

1. Determine opera t ing l i n e , e q u i l i b r i u m l i n e , and NS s i m i l a r t o

C a l c u l a t i o n B.

2. Ca l cu la te Eo.

Eo = Ns/Actual number o f stages.

3 . Determine average Murphree solvent-phase stage e f f i c i e n c y , EMS,

g r a p h i c a l l y by assuming an e f f i c i e n c y , c o n s t r u c t i n g a pseudo

e q u i l i b r i u m l i n e based upon d r i v i n g fo rces equal t o t he f o l l o w -

ing , Y - ( Y - Y*) ( E f f . ) and stepping o f f stages us ing the

pseudo e q u i l i b r i u m l i n e . Continue assuming e f f i c i e n c e s u n t i l

t he number o f stages i s equal t o t he ac tua l stages.

Calculation E - Scrub Section Calculation, A-Type Pulse Column

1. Determine m. m = 0.1 i s sui table fo r a l l flowsheets.

2. Calculate number of HN03 stages.

- log ( M ) (1 - P ) + p Ns

- log 1/P

HN03 in organic stream entering, g/!2 M = HN03 in organic stream leaving, g/!2

- aqueous flow L/V - organic flow

3. Calculate number of HN03 transfer units:

N and P are as above.

4. HETS and HTU calculations a re similar to Calculation A , above.

Calculation F - Scrub Section Calculation, Mixer-Settler Extractor

1. Calculate N s y s imilarly t o Calculation E.

2. Determine Eo:

0 = NS/Actual stages.

3 . Determine EM.

L = volume aqueous per uni t time, V = volume organic per uni t time, M = X 1 / X 2 f o r extraction. Y 1 / Y 2 f o r s t r ipping,

m = slope of equilibrium l ine ,

P = slope operating line/slope equi 1 ibrium l ine , Em = Murphree stage efficiency, NS = number of stages, N t = number of t ransfer units.

2.2 PULSE GENERATORS

Two main types of pulse generators are currently in use: niechanically- and air-driven generators. These are described in the following subsections.

2.2.1 Description of Types

Several types of mechanical ly-driven pulse generators are described

by Hammond. (57)

Crank-Driven Piston Pulser. A type of pulser which has been used

extensively in the chemical separations plants i s the mechanically-driven

piston close-coupled t o the drive mechanism. A gear motor drives a s l ider -

crank or Scotch-yoke mechanism to convert rotary t o sinusoidal l inear

motion. Usually, amplitude i s fixed by the crank throw, b u t pulse fre-

quency i s varied remotely by changing the frequency of the drive motor.

Pistons are sealed by graphite rings which are s p l i t and spring loaded

for wear compensation.

This type of pulser, which has been used to pulse columns u p t o 30 in .

in diameter, has accumulated many thousands of hours of operating times

without serious mechanical problems in our nuclear plants. However, the

pulser i s bulky, takes u p a large amount of cel l space, requires an

elaborate lubrication system t o the drive mechanism, requires an expensive

frequency-changing system, and has a f i n i t e s ignif icant piston leakage r a t e ,

which must be returned to the main process stream. These drawbacks make

th i s type of pulser unsuitable fo r some applications.

A pulse system has been developed in an attempt to meet some of these problems, par t icular ly for smaller nuclear chemical plants where cell space i s very limited and stream flows are so small that almost any leakage i s

intolerable. The drive i s mounted outside the cel l where i t i s accessible

for lubrication, frequency and amplitude changing, and maintenance. The

piston drive shaft pierces the radiation barr ier through a l iquid sea l ,

dropping through the upper pulse leg to the piston. Piston leakage col lects

i n the upper pulse leg until s t a t i c head i s balanced i n a "U-tube" system. Thus, the only sealing requirement of the piston i s tha t leakage does not seriously reduce the pulse amplitude. We have operated solid graphite "plug pistonsN for millions of cycles w i t h no measurable affect on pulse amplitude. These pistons are nonwear, compensating, and cheaper compared to ring-type pistons.

Electromagnetic-Powered Piston Pulser. Another way t o operate a "U-tube" pulse system i s t o use an electromagnetic-driven piston w i t h the piston located a t the bottom of the "U". The pull direction of the magnets can be successfully reversed a t the desirable frequency using sol id-s tate switching devices. Although electromagnetic pulsers have operated several million cycles i n "cold" t e s t s , process evaluation i s a future project.

Bellows Pulser. A t h i r d approach to leak-free pulsers i s to replace the piston w i t h bellows or diaphragms. Commercially-available Teflon bellows, for example, have operated up to 100 million cycles in "cold" service without rupture. However, the presence of even small amounts of nuclear radiation changes the mechanical properties of Teflon enough to promote rapid bellows fa i lure . A nonradioactive "buffer" l iquid has been successfu l ly used to shield Teflon bellows from alpha or beta radiation. A similar approach in a gamma f i e l d requires expensive or bulky lead or other types of external shielding plus "bleeding" of cold extractant 1 iquid ( i .e. , organic) into the pulse leg below the piston. Even so, back-mixing of

radioactive raff inates often .occurs, resulting in be1 1 ows exposure and early fa i lure .

Radiation damage can be avoided by using metal bellows. Until recently, metal bellows were noted mostly f o r short l i f e w i t h most types fa i l ing i n less than 1 million cycles. However, a s ta in less s teel bellows has operated i n cold service almost 10 million pulse cycles without rupture.

Pulse Leakage and A i r B leed ing

To i n s u r e t h a t no a i r i s between t he p i s t o n and t he f l u i d be ing pulsed,

weep ho les i n t h e p i s t o n face were cons idered a v i a b l e method of c o n t i n u a l l y - -

b l eed ing t h e a i r . A 21.2-in. d iameter p u l s e r was t e s t e d by McCarthy (75) ,, determine t h e e f f e c t of ho le d iameter on leakage p a s t t h e p i s t o n . He found

t h a t leakage p a s t t he p i s t o n was n o t app rec iab l y a f fected by pu l se frequency

(see Table 16). To ma in ta i n a s t a t i c balance (no l i q u i d leakage p a s t t h e

p i s t o n ) between t h e pu l se l e g and t h e pu l se column w i t h t h e column f u l l ,

a i r a t pressures f rom 8.0 t o 13.5 p s i g was a p p l i e d under t h e p i s ton . A t 3 9.5 p s i g and w i t h a 3/64- in. d iameter weep ho ld , 1.6 s tandard f t /min o f

a i r was r e q u i r e d t o m a i n t a i n a balance. Wi th a 3/32- in . d iameter weep 3 ho le , 4.0 s tandard f t /min o f a i r a t 9.5 p s i g was requ i red .

TABLE 16. Average Leakage Rates Past t he P i s t o n

Weep Hole Variables

Leakage Rate, gpm(a) Organic Water

Plugged 0.03 0.07

3/64-in. diameter 0.15 0.19

3/32-in. diameter 0.57 - - {a) gallon per minute

Bleed ing t he a i r o u t of t he pu l se l e g under s t a r t - u p c o n d i t i o n s was

rap id , even w i t h t h e p i s t o n weep h o l e plugged. The l o n g e s t t ime r e q u i r e d

t o b l eed t h e pu l se l e g was 36 min which i nc l uded a c o l u m n - f i l l i n g t ime of

30 rnin.

C a v i t a t i o n

I f t h e a l g e b r a i c sum o f t h e abso lu te pressures (atmospheric, hydro-

s t a t i c , and a c c e l e r a t i o n ) i s l e s s than t he vapor pressure, c a v i t a t i o n w i l l

occur and t h e system w i l l be inoperab le . Cooper (31) developed an equat ion

t o c a l c u l a t e t he minimum va lue o f t h e a c c e l e r a t i o n pressure i n t he pu l se

l e g of a pu lsed e x t r a c t i o n column. It shows t h a t

where

k = half-cycle pulse volume, in. 3

1 = length of pipe, f t p = specific gravity W = cycles per unit time, cycles/min

D = diameter of pipe, in.

Pulse Generator Power Requirements

A study of the power input to a pulse generator was conducted by Jealous . (65) The power required to pulse a liquid-liquid extraction column i s determined by the s t a t i c head of the l iquid system, the acceleration and deceleration forces on the l iquid system, and the f r ic t ion losses. The theoretical total power that must be applied to the liquid-liquid system

by the pulser i s given by Equation (2) .

where the equation fo r y defines the cyclic motion imparted to the l iquid system by the pulse generator. Power i n p u t data obtained on a 50-ft pulse column that i s 24 i n . i n diameter a re presented i n Reference 67 as well as information on development of the power formula and the means of experimentally evaluating the formula. The nomenclaure for th i s equation i s :

g = acceleration due to gravi ty , f t / s e c 2

= conversion factor, l b mass-ft/lb force-sec 2 go L1 = ef fec t ive height of column, f t L2 = t o t a l length of pulse l i n e from column to point of P2 f t

1

n = number of p la tes i n column I

S, = cross-sectional area of column, f t 2 I

S2 = cross-sectional area of pulse 1 ine , f t 2

t = time, sec y = f ract ional f r ee cross-sectional area of screens

= ef fec t ive density of f l u i d in column, I b / f t 3 P1

= density of f lu fd in pulse l i n e , I b / f t 3 2 y = l i nea r displacement of pulser rod o r l iquid in column, f t

Effect of Pulse Wave Shape

Thornton ( I 1 ' ) used data from a 2.9-in. diameter column containing pla tes w i t h 0.125-in. holes, 13 t o 62% f r ee area and 1/2- to 2-in. p la te spacing i n an attempt t o define the e f f ec t of pulse wave shape on pulse column operation. He developed two complex equations corre la t ing system physical proper t ies , pulse power diss ipated, and column internal geometrics versus capacity and HTU. The data corre la t ions show l i t t l e influence of the type of pulse wave ( s i ne , saw-tooth, and square wave) on e i t h e r capa- c i t y or eff ic iency.

To determine the e f f ec t of a i r purging f o r bottom interface controls on the operation of a pulse column, de ~ i t t e ( ~ ' ) carr ied out t e s t s in a 2.95-in. diameter column. The column in te rna l s were 23% f ree area s ieve pla tes on a 1.96-in. spacing. The presence of a i r in a membrane-pulsed u n i t markedly decreased the pulse amplitude while no decrease in pulse amplitude was found in an air-pulsed u n i t . The presence of a i r tends t o increase column capacity and reduces the build-up of "crud" on the in terface .

Several air-driven pulse generators have been examined. Some of the most pertinent studies are detailed i n the following subsections.

2.2.2 Air-Driven Pulse Generators

An a i r pulser was recommended by Bruns ( I 6 ) fo r use on a plutonium extraction pulsed column to eliminate frequent maintenance and t o obtain technical and operating information. This a i r pulser has given excellent performance and has advantages over the or iginal ly planned piston-type bellows or the existing Teflon bellows now i n use in plutonium processing. Some advantages are lower cost , most of the equipment i s easi ly accessible (almost a l l parts can be i n a re lat ively "cold" zone), no piston leakage or bellows fa i lu re problems, simplified equipment, smaller diameter pulse

leg, and less column downtime required for equipment change.

The main disadvantage of the a i r pulser may be the necessary control instrumentation. One such pulser d i d not require an automatic amplitude stabi 1 i zation control system, b u t s t i l l had good column efficiency and no

loss i n capacity.

Advantages of Air Pulsers

According to Hammond ( 5 7 ) the a i r pulser appears to be the ideal solution to the problems of pulse leakage and in-cell equipment maintenance. Air i s piped to the pulse leg through an accumulator and control valve, both of which are i n the "cold" zone. The control valve i s opened and closed, a l ternately pressurizing and exhausting the pulse leg to pulse the column. Advantages of the a i r pulser include:

no moving mechanical parts i n the cell to be repaired and serviced by expensive remote sys terns, expensive cell space i s conserved, process l iquids are completely contained, whether or not the system

i s i n operation, both pulse amplitude and frequency can be varied without the use

of costly remote control systems.

Uses of Air Pulsers in Uranium Purification

The design of air-driven pulsers for extraction columns i s discussed by ~ a i r d ( ~ ) who also presents several applications including the i r use in

uranium purification. The theory of a i r pulsing i s examined i n de t a i l .

2.3 CONCATENATED PULSE COLUMNS

A concatenated pulse column can provide the equivalent height of a

t a l l column by connecting two or three short columns in ser ies and using

one pulse generator. Several methods of achieving concatenation are summarized in the following subsections.

2.3.1 Packaged Extraction - Parti t ion-Strip Column

Ludl ow (73) used a standard pulse column operated with a pulse gene-

rator a t the bottom and fed in the middle by the feed stream under flow

control. The extractant enters the column under flow control a t the bottom.

Scrub solution i s introduced a t the top under interface control to maintain

an organic layer in the top of the column. Waste leaves the column under

flow control a t the bottom, thus leaving the extractant a f t e r i t has served i t s purpose overflowing from the t o p of the column. The organic-to-air

interface in the pipe will be pulsing a t the identical volume and frequency

of the solution a t the pulse generator. This will happen i f : 1 ) t h i s

extractant i s conducted through a pipe of suff ic ient volume to be several times the pulsed volume, 2 ) the diameter of th i s pipe i s suff ic ient ly large to avoid cavitation, and 3 ) the column and the pipe are maintained f ree of a i r by a sui table a i r t r ip . If instead of venting th i s pipe to the atmos-

phere i t i s conducted into the bottom of a simple column the operation can

be described as follows.

The compound column operates as described above providing a pulsating

organic stream into the bottom of the simple column; thus commuting

the pulse generator to the simple column.

The s imple column has scrub s o l u t i o n e n t e r i n g a t t he top under i n t e r -

face c o n t r o l t o p rov ide a l a y e r o f o rgan ic a t t he top o f t h e column.

The aqueous f lows c o n t i n u a l l y down t h e s imple column, thus scrubbing

the organic phase and i s removed a t t h e bottom under f low c o n t r o l - - i n

t h i s case being fo rced by a pump i n t o t he middle of t h e compound column,

thus accompl ishing t h e f lowsheet requirements.

Th is scheme of p i p i n g and opera t ion a l lows one pu l se generator a t t h e bottom

of t h e f i r s t column t o p rov ide f l o w f o r t h e organ ic and a l s o p rov ide p u l s i n g

f o r t he e n t i r e b a t t e r y o f columns o f t he uranium-par t i t ion-decontaminat ion

cyc le . The e n t i r e column b a t t e r y cou ld be assembled as a packaged u n i t ,

coupled w i t h t he concent ra to r u n i t and cou ld p rov ide t h e e n t i r e so l ven t

e x t r a c t i o n separa t ion f a c i l i t y needed. E f f l u e n t streams from t h e package

and i t s assoc ia ted concent ra to r would be:

waste organic f o r t rea tment i n con tac t f a c i l i t i e s and repumping i n t o

t h e package u n i t ,

d isposable condensate f rom t h e evaporator,

concentrated decontaminated uranium i n the form of a u rany l n i t r a t e

s o l u t i o n ,

a decontaminated p lu ton ium s o l u t i o n , and

an aqueous waste s o l u t i o n con ta in ing t h e f i s s i o n products.

By s u i t a b l e subd i v i s i on o f t he columns i n t he u n i t s , any reasonable he igh t

can be a t t a i n e d (e.g., t he b a t t e r y used i n t he Purex process cou ld be b u i l t

w i t h an o v e r a l l equipment h e i g h t o f 25 f t ) .

2.3.2 Uses o f Check Valves

I n another method o f ach iev ing concent ra t ion developed by Jealous

and Lieberman (66) t h e connect ions are made w i t h p a i r s o f tubes a p p r o p r i a t e l y

check-valved t o accommodate the f l o w o f t h e two immisc ib le l i q u i d s . I t was

concluded t h a t :

* a concatenated column o f f e r s n o t o n l y equal, b u t sometimes g rea te r ,

e f f i c i e n c y than a t a l l column,

e t he bes t check va l ve i s a f l o a t i n g d i sc ,

the diameter o f the t rans fe r tubes must be such t h a t c a v i t a t i o n i s

avoided,

in te rmed ia te phase disengaging chambers a re necessary a t the top and

bottom of each sec t i on t o f a c i l i t a t e t h e breaking of emulsions formed

by passage through the check valves,

power requirements a re u s u a l l y lower than t h e power requ i red f o r a

t a l l column, and

wider pressure v a r i a t i o n s a t t he pu l se r a re encountered w i t h concatenated

co l umns.

2.4 BACK-MIXING

Small q u a n t i t i e s of co lo red dye were i n j e c t e d i n t o the packed sec t i on

of a pu lse column by S w i f t ; ( l o 6 ) t he c o l umn c o n f i g u r a t i o n and opera t ing

cond i t i ons a re 1 i sted i n Tab1 e 17. By i n t roduc ing co lo red organ ic ( d i spersed

phase) drops t o determine the amount of coalescence t a k i n g p lace i n pu lse

columns du r ing emulsion operat ion, S w i f t demonstrated t h a t : a) e s s e n t i a l l y

no coalescence occurred, b ) t h e range o f average drop v e l o c i t i e s was r e l a -

t i v e l y l a r g e and the drop s i z e d i s t r i b u t i o n of t he co lo red organ ic phase

was n o t s u f f i c i e n t t o exp la in the v e l o c i t y range ( th ree - t o f i v e f o l d ) , and

c ) some d rop le t s were a c t u a l l y c a r r i e d backward. I n t r o d u c t i o n o f t r a c e

q u a n t i t i e s of co lo red aqueous (cont inuous phase t o the packed sec t i on ) i n d i - cated t h a t considerable back-mixing o f the cont inuous phase ex is ted , c o l o r -

i n g being c a r r i e d upstream aga ins t the n e t f low of the cont inuous phase.

TABLE 17. Column Conf igura t ion and Operat ing Condi t ions (a )

Pla te Spacing = 2.00 in. Phase Ratio L/V = 0.5

P la te Hole Size = 0.40, 0.125 in . Continuous Phase = H20

P la te Open Area = 22.7% Dispersed Phase ="Supersol"

Volume Velocity = 500 g a l / h r / f t 2 Frequency = 60 t o 80 cycles/min 1000 gal / hrlft.2

( a ) 2.00 i n . I.D. Column, 27.5 in. nominal packed height; colored phase introduced 6 in . from bottom of packing.

2.4.1 Types o f Back-Mixing

Three mechanisms f o r back-mixing a r e proposed. The f i r s t type i s g ros s eddies i n t h e cont inuous phase. The edd ie s have a s c a l e (mixing l e n g t h ) o f column d iameter o r d e r of magnitude poss ib ly caused by: 1 ) s l i g h t t i p p i n g o f the p l a t e s , 2 ) a l ignment of t h e c a r t r i d g e i n the column i n such a manner

t h a t the c l ea rance between c a r t r i d g e and wall has a maximum a t one s i d e o f

the column, 3 ) a n i s o t r o p i c p l a t e s (ho l e s plugged, v a r i a t i o n i n open a r e a a c r o s s the p l a t e , etc. ) , and/or 4) unequal pu l se d i s t r i b u t i o n a t the bottom of t h e column. Small edd ie s have a s c a l e magnitude on t h e o rde r of drop

d iameter fo l lowing i n the vo r t ex t r a i l of r a p i d l y r i s i n g drops a r e t h e second type of back-mixing devices . The t h i r d device is entrapment of continuous phase i n a semif ixed l a t t i c e of d r o p l e t s ( p a r t i c u l a r l y under high holdup condi t i ons near f 1 oodi ng ) .

The n e t e f f e c t of back-mixing e i t h e r of t h e cont inuous o r d i spe r sed phase ( o r both) is complex, l e ad ing no t only t o increased holdup o f d i s - persed phase b u t , probably more impor tan t , t o decreased d r i v i n g f o r c e

f o r mass t r a n s f e r and p a r t i a l cocu r r en t flow o f the two phases. Theore t ic -

a l l y , complete backmixing would r e s u l t i n on ly a s i n g l e mass t r a n s f e r s t a g e f o r the e n t i r e column.

I f the g ros s eddy mechanism pos tu l a t ed i n this s e c t i o n i s p r e s e n t , back-mixing of the cont inuous phase w i l l occur over a l a r g e r and l a r g e r d i s t a n c e a s the column d iameter i s increased . Thus, scale-up e f f e c t s a r e

c o n s i s t e n t w i t h t h e proposed model.

s w i f t ( l o 7 ) cont inued i n v e s t i g a t i o n s using a 2.000-in. I.D. x 27.5 i n . packed he igh t pu l se column f i t t e d w i t h a t a p l oca t ed 6 i n . above the bottom of t h e packed s e c t i o n , pe rmi t t i ng the in t roduc t ion of a 1/16 in . O.D.

s t a i n l e s s s t e e l c a p i l l a r y tube. Through th i s tube a 64 g/a MnSO s o l u t i o n from a 50 o r 100 ma s y r i n g e was f ed cont inuous ly a t a r a t e of approximately 1 malmin (0.5 t o 2% o f the t o t a l aqueous phase f low) . Samples were withdrawn

a t s eve ra l po in t s above i n j e c t i o n a t a r a d i u s of 0.50 i n . by means of a

1/16 i n . O . D . s t a i n l e s s s t e e l c a p i l l a r y extending down through t h e per fora- t i o n s of t h e c a r t r i d g e p l a t e s . ( a ) A sample of t h e e f f l u e n t composition a t

e q u i l i b r i u m was a l s o taken t o g i ve the average composit ion a t the i n j e c t i o n .. p o i n t ( C o ) The r e s u l t s obta ined are shown i n Table 18.

TABLE 18. Summary of Back-Mixing Runs

Vol ume Veloci ty

Volume (sum o f both Pulse P la te H a l f ~ e i s h t ( ~ )

Flow phases), Frequency, Amp1 i tude, Spacing, h l /2 &b i n . Rat io U /L& g a l / h r / f t 2 cycle/niin i n . i n . in.2/min

(a) Height over which concentration o f t r a c e r reduced by a f a c t o r o f 2 . (b) E = Eddy diffusivity.

S w i f t concluded t h a t the c a l c u l a t i o n i nd i ca tes t h a t f o r the same

pu lse ampli tude, E i s l a r g e l y independent of the d iscont inuous phase f low

r a t e ( V ) , o r frequency. Thus, t he degree of back-mixing i s a f u n c t i o n

on ly o f t he continuous phase f l o w r a t e (L) over the range studied. The

e f fec t of frequency i s shown a t 70 and 90 cycles/min, respec t i ve l y , t o be

smal l , the ha l f he igh t changing by o n l y 5%, w h i l e the e f f e c t o f p l a t e spa-

c i n g (1 and 2 i n . ) i s n e g l i g i b l e .

The e f f e c t o f volume v e l o c i t y i s shown a t approximately 90% o f f l o o d i n g

t o be small and probably on l y r e l a t e d t o the continuous phase r a t e . The

(a ) The p l a t e c a r t r i d g e used had a d i ameter o f 1.988 i n . , g i v i n g a 0.01 2 i n . d iametra l c learance i n the p r e v i s i o n bore column. Car t r i dge geometry was : 0.125 i n . diameter holes, 24.5% open area, and 1 .OO i n . o r 2.00 i n . p l a t e spacing. The l i q u i d system was d i s t i l l e d water (con- t inuous) , Penn. Ref. Co. "Supersol" (d ispersed) .

e f f e c t o f pu lse ampli tude i s shown a t 1.125 and 0.50 i n . , r espec t i ve l y . It

seems reasonable t h a t h i s a cont inuous f u n c t i o n o f ampl i tude through 1 /2

the reg ion where the ampli tude equals p l a t e spacing. I n t he m i x e r - s e t t l e r

reg ion o f opera t ion a considerable change i n the back-mixing mechanism i s

probable.

I t was expected before the runs were s t a r t e d t h a t t he volume f l o w r a t i o ,

L/V, would be a major f a c t o r , and t h i s v a r i a b l e was chosen t o correspond

approximately t o HA e x t r a c t i o n sec t ion , HA scrub sec t ion , and 1B e x t r a c t i o n

sec t ion , respec t i ve l y , the l a t t e r having the lowest L/V spec i f i ed f o r Purex.

The r e s u l t s i n d i c a t e t h a t back-mixing w i l l be severe under 1B cond i t ions ,

hli2 being 8.2 i n .

The e f f e c t o f back-mixing w i l l depend l a r g e l y on the e x t r a c t i o n f a c t o r L mV f o r e x t r a c t i o n , f o r scrubbing and s t r i p p i n g ) o f the system i n ques-

t i o n , i nc reas ing w i t h increas ing e x t r a c t i o n f a c t o r . An order of magnitude

es t imate o f the e f f e c t can be ca l cu la ted f o r t he case of a low e x t r a c t i o n

fac tor , i .e. , zero "back pressure," a case where back-mixing should have a

minimum e f f e c t . For low e x t r a c t i o n fac to rs , a 50% reduct ion i n concent ra t ion

of d i f f u s i n g component i n the r a f f i n a t e i s accomplished i n approxiniately

0.7 t r a n s f e r u n i t s ( o v e r a l l r a f f i n a t e f i l m bas is ) . Assuming an HTUOD =

1.0 ft, o r a 50% concent ra t ion reduct ion i n 0.7 f t w i t h back-mixing present,

and an h f o r back-mixing = 0.17 ft, the equ iva len t HTU w i t h back-mixing 1 / 2

completely e l im ina ted would be 0'70 0. 70 - = 0.76 f t o r a 24% ga in i n he igh t

e f f i c iency . Since t h i s i s a probable minimum e f f e c t , back-mixing may have

considerable importance and should be considered i n pu lse column design and

operat ion.

2.5 THEORETICAL CONSIDERATIONS

A number o f authors have attempted t o r e l a t e the phys ica l p rope r t i es

o f t he phases, t he geometry o f t he pu lse column c a r t r i d g e , and p u l s i n g

c h a r a c t e r i s t i c s . These s tud ies a re summarized i n t he f o l l o w i n g subsect ions.

2.5.1 Effect of Operating Parameters on HTU - Teflon P la te Cartr idge

A number of runs were made i n a 1/2-in. diameter g lass pulse column

containing Teflon pla tes . The p la tes were spaced 1 t o 2 i n . a pa r t and had

between 12 and 60% f r e e area w i t h holes 0.025 t o 0.04 i n . i n diameter. The

r e su l t s reported by ~ u b i n ( ~ ~ ) indicated t ha t HTU values between 6 and 10 in.

could be obtained f o r the water-uranyl nitrate-dibutoxy ethylene glycol

systems. HTU values were 5 t o 70 in . f o r the water-uranyl n i t r a t e -

cyclohexane system. The following general iza t ions were made:

1 ) The volume throughput r a t e f o r each of the two phases cannot exceed

the pulse amp1 i tude times frequency product.

2 ) The optimum displacement per pulse should be l e s s than the volume

between the pla tes .

3) The pulse frequency should be as high as possible without flooding.

An equation f o r HTU values obtained w i t h the polar phase continuous was proposed. I t r e l a t e s HTU t o the polar phase flow ( L ) the nonpolar

phase flow ( G ) , the slope of the equi 1 i brium curve ( m ) , and several

constants a , b y c , d, and e . The re la t ionship i s :

2.5.2 Effect of Design Parameters on HTU - Sta in less Steel P la te Cartridge

el aga") reported data obtained on the methyl isobutyl ketone-acetic

acid-water system i n a 45-in. high, 1.5 i n . diameter pulse column containing

36 s t a i n l e s s s t e e l p la tes having 1-in. spacing, 23% f r e e area and 1/3-in.

diameter holes. Pulse amplitude and frequency were varied from 0.125 t o

2 i n . and 20 t o 80 cycles/rnin, respectively. The HTU values a r e l i s t e d

i n Table 19. A t high and low amplitude times frequency products the curves

of HTU versus a product a t constant frequency a r e nearly superimposed.

Belaga a l so determined t ha t :

1 ) c lose r p la te spacing decreased HTU values,

2) reduced hole s i z e decreased HTU values, and

3) addit ion of a su r fac tan t t o reduce i n t e r f ac i a l tension decreased the

HTU values b u t created an emulsif icat ion problem.

TABLE 19. HTU Values

Pulse Frequency HTU, ' times Amp1 i tude,

in. in./min

I t was concluded that the operating variables, pulse amplitude and

pulse frequency do not d i rec t ly a f fec t the HTU values b u t influence

secondary variables, such as ra te of drop diameter growth, drop s i ze ,

fa l l ing drop velocity, and hold u p which do af fec t HTU. The secondary

variables are influenced by the system properties, i . e . , specif ic gravity

difference and interfacial tension.

Burkart (22 also compared cartridge geometry and pulse conditions in a

1 -in. diameter column with the methyl isobutyl ketone-acetone-water system.

The range of variables studied are l i s t ed below.

Plate Spacing, in . 1 to 2

Hole Diameter, in. 1/32 to 1/16

Free Area, % 13 to 25

Pulse Amplitude, in. 0.25 to 1.0 Pulse Frequency, cycles/rnin 25 t o 50

I t was found that :

1 ) increasing the pul se ampl i tude, pul se frequency, hole diameter and

plate spacing led to higher HTU values,

2 ) HTU values were more sensi t ive to pulse power input a t low values of

ampl i tude times frequency, and

3) HTU values varied with both amplitude and frequency.

2.5.3 Effects of Design and Operating Variables on Column Efficienc;~

The system l i s t ed in Table 20 was used in studies by Swift; (1Ga a preliminary correlation of the e f fec t of cartridge geometry (plate spacing, - . perforation hole diameter, fraction open a rea ) , pulse (frequency and amp1 i - tude) , and volume flow r a t i o variables, was obtained for a sieve plate

pulse column in the region of emulsion type flooding with a noncoalescing

system and in the absence of a distributed solute. Although not a dimen-

sionless equation, i t correlates the resul ts of 180 runs over a wide range

of the above variables with an average deviation of less than 10%. The

properties given in Table 20 are for the average temperature of a l l runs

(\23OC), the variation from run to run having been found negligible.

TABLE 20. System Used in Swif t ' s Correlation

DISPERSED PHASE (Amsco 125-90W)

Specific Gravity 25OC

Viscosity

Interfacial Tension (with mutual ly saturated water)

0.751 gm/ml

13.2 mill ipoise

CONTINUOUS PHASE (Water Saturated with Amsco 125-90W)

Speci f i e Gravi ty

Viscosity

0.998 gm/ml 9.1 mill ipoise

A t constant flow ra t io the correlation i s as follows:

where C1 and C2 a r e functions of the physical properties of the chemical system used. As can be seen from t h i s correlation, the fraction open area, plate spacing, and hole diameter have a strong ef fec t on the sens i t iv i ty of the flooding capacity to the pul se frequency-amp1 itude product, In future pulse column design i t would seem desirable to provide as f l a t a curve as

possible when plott ing the log ( U c + U d ) versus fa. This can be done by

increasing the fraction open area, increasing the plate spacing, and by

decreasing the perforation hole s ize.

Although the e f fec t of specif ic physical properties is not presented i n

t h i s report , these variables will appear i n the constants C1 and C2. Thus, for any given system (within the l imits of noncoalescing systems) only two experimental runs are necessary t o determine the flooding curve over a wide range of conditions.

Important Variables in Pulse Column Operation

The variables determining the behavior of a pulse column both i n mass

t ransfer efficiency and flooding considerations are summarized below. I n

the study only the volume flow ra t io , pulse amplitude, frequency, plate thickness are considered; a l l other variables were held as near constant as possible.

Flowsheet Determined Volume flow ra t io Density of the continuous phase

Density of the dispersed phase Viscosity of the continuous phase Viscosity of the dispersed phase Interfacial tension Solute direction of t ransfer and ra te

Pulse Amplitude Frequency

Shape

Cartridge or Packing

Plate spacing

Perforation hole s ize

Fraction open (perforated)

Plate thickness

Plate t o column wall clearance

Wetting character is t ics

The range of variables studied and the cartridge description are sum-

marized in Tables 21 and 22.

TABLE 21. Range of Variables Studied

Column Diameter = 2.00-in. I.D. M i n i mum Maxi mum

Volume Flow Ra t i o 0.143 11.3

Frequency, cyc/mi n 30 200 Amp1 i tude, i n . 0.375 1.60 Frequency-Amp1 i tude Produce, i n . /mi n 2 5 205

P l a t e Spacing (face t o face) , i n . 0.5 4.0 Pe r fo ra ted Hole Diameter, i n . 0.020 0.186 F rac t i on Open Area, % 0.081 0.414

Discussion of Variables Studied

Volume Flow Ratio. Under conditions of low volume flow ra t io , U,/Ud

flooding normally takes place e i ther simultaneously over the en t i r e length

of the column or from the dispersed-phase ex i t end back through the column.

A t high values of U c / U d flooding occurs due to the classif icat ion of fine-

sized droplets to the dispersed-phase i n l e t end of the packing. T h u s , the

effect ive density difference i s lowered which hinders the s e t t l i n g , and

ultimately chokes the column while the remainder of the column operates

normal ly.

TABLE 22. Ca r t r i dge Descr ip t ion

Pl a t e Spacing Perforation Fraction Perforation Face t o Face,

cartridge(') H o l e Open Area, % Pattern - i n .

( a ) All plates 0.020 i n ( b ) 0.010 in. thick ( c ) 0.070 i n . thick

Triangle Triangle Tri angle Tri angl e Triangle Triangle Triangle Triangle Triangle Square Triangle Square Square Square Square Triangle Square Triangle

thick

One method f o r i n t e r p r e t i n g t h e e f f e c t of volume flow r a t i o i n spray and packed columns i s t h e "square r o o t p l o t " wherein u - " ~ i s p l o t t e d

L

versus udl". For the packed type of c o n t a c t o r this p l o t i s a s t r a i g h t

l i n e with a s lope o f -1 i n d i c a t i n g t h a t U c i s a cons t an t and t h a t the . . phase wi th t h e h igher flow r a t e i s c o n t r o l l i n g . For spray columns t h e

data plot are again s t ra ight l ines b u t with a slope indicating tha t the

dispersed phase i s more controlling. The behavior i n pulse columns i s similar to spray columns over a limited range of Uc/Ud<2.

. . Pulse Amplitude and Frequency. Increasing e i ther of these two variables

while holding the other constant yields increased energy i n p u t into the system ' resulting i n f i ne r dispersions and greater intensity and scale of turbulence. This produces higher dispersed-phase holdup and lower flooding capacities. I t may be tha t these two terms can be combined as a product to serve as a measure of the energy input, and fur ther , tha t the flooding capacity must approach zero asymptotically as the product i s increased.

I t has been shown experimentally by swif t ( lo8) tha t a t constant volume flow ra t io

log ( U c + U d ) = b - cfa

where b and c are constants.

Plate Spacing. The pulse frequency and amplitude measure the energy input to the system and the perforated plates provide the means by which th i s energy i s transformed into useful dispersion and turbulence. Thus, i t may be concluded that the e f fec t of plate spacing will be greatest a t higher pulse energies and negligible a t zero pulse. The data may be reduced to a single l ine by plotting U c + U d versus f a / l 0.32

Perforation Hole Size. This variable has i t s greatest e f fec t in generally decreasing the flooding capacity with decreasing hole s ize as might be expected, since smaller droplets resul t from smaller perforations. Decreasing the hole s ize also increases the sens i t iv i ty of the flooding capacity t o variation of the pulse [slope of log ( U c + U d ) versus f a plot] even to the extent that small holes may resu l t in greater capacities than large holes under conditions of h i g h pulse energy input. This apparently

anomalous e f fec t can be explained on the basis of the Reynold's number through the perforations; larger holes ( larger Reynold's number) yielding

greater j e t lengths resulting in increased turbulence and holdup between

plates. This j e t penetrates on the order of half the plate spacing and

resu l t s in a return stream ( in the manner of a fountain). With small holes

(<0.040 i n . ) the turbulence i s largely res t r ic ted t o the region immediately

around the plates.

Fraction Open Area. This variable has i t s greatest e f fec t in changing

the sens i t iv i ty of the flooding capacity t o pulse energy. Increasing open

fraction decreases th i s sens i t iv i ty which agrees with the Reynold's number

e f fec t c i ted above fo r variations in hole s ize. In the l imi t , as the frac-

tion open area approaches unity (spray column) the capacity will be unaffected

by pulse.

The ef fec t of hole s ize and fraction open area i s , however, apparently

more complex than can be explained by a simple Reynold's number. Interaction

between neighboring holes can be expected, particularly a t high fractional

open area.

Plate Thickness. Although varied over a range from 0.010 to 0.070 i n . ,

no consistent e f fec t was noted and, i f i t i s present, i t can be considered

negl igible.

2.5.4 Column Capacity and Efficiency as a Function of Dispersed Phase Holdup

Experimenting with the system water-toluene-acetone in a pulse column

containing plates having 0.125-in. holes, 23% f ree area and 0.75 in. spat- - .

ing , Thornton ( ' l 2 ) concluded tha t the following:

A sat isfactory method of pulsing using an a i r pocket t o i so la te the

pulsing mechanism from the process liquors has been demonstrated. In high-energy region and in the absence of undistributed solute

flooding can be correl ated by:

where

X f = l i m i t i n g hold-up of dispersed phase a t f l o o d i n g p o i n t

With t h e system tested, HTU ( 0 4

increases w i t h throughput up t o 50%

of the f lood ing po in t , beyond which the re i s l i t t l e e f f e c t .

I n h igher pulse-energy reg ion (HTU), i s small and can be considered

constant. (HTU)D although independent o f phase f l o w r a t e s i s a

f u n c t i o n of t he pu lse c h a r a c t e r i s t i c s of the system.

2.5.5 E f f e c t o f Operat ing Parameters on HTU - S ing le P l a t e Column

~ u ~ e n i o ( ~ ~ ) c a r r i e d ou t experiments us ing a s i n g l e pe r fo ra ted s t a i n -

l ess s t e e l p l a t e (5/12 i n . diameter holes, 11.6% f r e e area) i n a 2 - f t h igh

pulsed column. With an isobutano1:water system, an expression was demon-

s t r a t e d f o r aNTUC where aNTUC = NTU - NTUo ( a t a pu lse frequency of 0 ) .

where

f = pulse frequency, cyc lmin

o1 = 0.1 x f o r p l a t e a t center

a' = 0.03 x l o e 3 f o r p l a t e a t bottom

LC = continuous phase f l ow

LD = d ispersed phase flow.

It was shown f u r t h e r t h a t :

a t a pulse ampli tude of 0.25 i n . The term a2 i s i d e n t i c a l t o a ' as de f ined

above .

2.5.6 Effect of Drop Velocity and Pulse Conditions on Drop Size

Using data fo r 'both Purex extraction stripping columns obtained in a

3-in. I.D. column containing 23% f ree area, 0.925-in. diameter holes, and

a 2-in. spacing, Troutman ('18) found that as the velocity through the holes

increased from 0.065 to 0.31 f t / s ec the drop s ize increases, b u t when the

velocity increased beyond 0.31 f t / s ec , the drop s ize decreased. He also

found that the combination of a high pulse frequency and a low pulse ampli-

tude gave smaller drops than the reverse pulse conditions. I t was concluded

tha t a computer simulation of a pulse column could be made. The model was

not demonstrated due to the low degree of accuracy of the data correlations.

2.5.7 Effects of Operating and Design Parameters on Flooding Capacity and Efficiencv

The data from 23 pulse column papers using a wide variety of systems

and column character is t ics were correlated by Smoot ( lo ' ) t o produce the

following equations:

SIMPLIFIED FLOODING CORRELATION

0*63d0*458 Vc 0.01 43 K ApC (-1 ('c + = 0.144 0.207 0.20 Vd

Y '4J d

SIMPLIFIED HTU CORRELATION

where :

Ap = density difference between the phases, 1 b / f t 2

d = diameter of plate hole, f t

V, = continuous phase velocity, f t / h r

VD = discontinuous phase velocity, f t / h r

y = interfacial tension, I b / h r 2 2 3 $ = power function, f t /hr

pd = viscosity of discontinuous phase, 1b/hr-ft

d = hole diameter, f t 1 = plate spacing, f t

2 Dv = diffusivi ty of solute , f t /hr Yo = pulse frequency times pulse amplitude divided

by fractional f ree area.

Nomographs relating the above variables are included i n the paper. (101

2.5.8 Operating Variables Affecting HTU

Soboti k (lo') carried out studies w i t h the acet ic acid:methyl isobutyl ketone:water system i n a 3-in. diameter pulse column. The column internals were s ta in less s teel plates having a 1.5-in. spacing, 0.125-in. diameter holes, and 18.7% f ree area. He found tha t HTU values were in the range of 5 to 7 i n . and tha t HTU values:

decrease as pulse velocity increases until jus t pr ior to flooding and then increase, were lower with the organic phase continuous, were lower when t ransfer was ketone t o water and the organic was the continuous phase, decrease w i t h decreasing A / O r a t io , and decrease when plate material changed from stainless s teel t o polyethylene for ketone to water transfer.

2.5.9 Effect of Operating and Design .Variables on Flooding Capacity and Efficiency

In an overview a r t i c l e of pulse column performance ~ a i l l e ( ~ ) concluded

that : colunin diameter had no ef fec t on flooding character is t ics ,

HTU values increased w i t h hole s ize and free area, HTU values were proportional to column diameter i n f ee t divided

by two,

an increased plate spacing increases both capacity and HTU, * as the product of the pulse frequency times pulse amplitude increases,

HTU values decrease sharply and then increase s l ightly , the pulse wave form has no ef fec t on column efficiency, a t a given value of pulse frequency times pulse amplitude HTU

increases as the total flow ra te increases, and HTU values increase w i t h increasing temperature,

Effect of Operating Variables on Holdup

Sehmel (97) determined the e f fec t of pulse column variables on hold-up, which i s defined as the average percent of to ta l volume between sieve plates

occupied by the dispersed phase a t steady-state conditions. A 1.97-in. diameter column containing a cartridge of plates having 0.125-in. diameter holes, 23% f ree area, and a 1.98-in. spacing was used with the water:hexane or benzene or methyl isobutyl ketone system. He found that :

hold-up i s independent of the continuous phase volume veiocity , hold-up decreases as pulse amplitude increases, and hold-up a t low pulse frequencies i s high, decreases to a minimum and then increases until flooding occurs.

2.5.11 A Review of Previous Flooding Correlations

A review of previously generated pulse columns flooding correlations i s presented by McCallister and Ryon (74) who define flooding as: "The

volume fraction of the dispersed phase, i . e . , the holdup, as measured a t

a given s e t of operating conditions." Hold-up measurements are made a f t e r 30 m i n of steady-state operation. This measurement i s then repeated a f t e r 60 m i n of operation. If the two hold-up readings agree, the flooding region has not ye t been reached. If the 60-min reading gives a s ignif icant ly higher reading, then the flooding point has been passed. If one plots hold-up versus pulse frequency (holding flow rates and pulse amplitude constant), the flooding point will be defined as the pulse frequency a t

which the 30-min hold-up curve diverges from the 60-min hold-up curve.

A review of ex i s t ing cor re la t ions follows:

Thornton's Correlat ion

Thornton's corre la t ion f o r flooding uses the cha r ac t e r i s t i c drople t . *

ve loc i ty , V o , derived from a consideration of the theory of hindered

s e t t l ing, .- .

Smoot and Babb's Correlation

Smoot and Babb combined the data of others i n to another equation

derived from dimensional analys is as fo l lows :

Notice t h a t nearly a l l of the dimensionless groups on the right-hand s ide

of the equation a r e ident ica l w i t h those Thornton used.

B a i l l i e ' s Correlat ion

B a i l l i e determined emulsion flooding data over a wide range of proper-

t i e s of the two phases. For a 1.00-in. column using a 1.94-in. spacing,

70 cycles/min pulse, w i t h p la tes having a hole diameter of 0.111 i n . and

f r e e area of 0.230, Ba i l l i e derived the following equation:

Baillie's characteristic of flooding, the left-hand side of the equation,

i s the same as Smoot and Babb's. Baillie also used the pC in the denominator

of the fourth term on the right-hand side instead of ap.

The range of variables used in the three correlations are compared

i.n Table 23 while the net exponents of the physical properties are shown

in Table 24.

TABLE 23. Range of Variables Used by Baillie, Smoot and Babb and Thornton

Variable B a i l l i e (1961 Smoot and Babb (1959) Thornton (1 958)

" c 1.9 - 10.6 cp 1.00 cp 1.06 cp

'' D 1.1 - 5 . 6 ~ ~ 0.486 - 1 . 3 2 ~ ~ 0.486 - 0.928 cp

1.13 - 1.37 g/cm3 1.00 glcm 3 '=c 0.996 - 0.998 g/cm3

0.773 - 0.887 g/cm3 0.772 - 0.905 g/cm3 0.772 - 0.905 g/cm 3

D Ap 0.302 - 0.593 g/cm3 0.0903 -. 0.0307 g/cm3 0.0903 - 0.307 g/cm3

Y 8.9 - 15.8 dyn/cm 8 .5 - 40 dyn/cm 8 .5 - 40.0 dyn/cm

A 0.500 in . 0.104 - 0.500 in . 0.14 - 0.87 in .

F 70 cpm 14.5 - 4 2 0 c p m 9 0 - 420 cpm

D 1.000 i n . 1.92 - 12 in . 2.78 - 12 i n .

d 0.111 in . 0.0625 - 0.125 0.0625 - 0.125

L 12 f t 3 - 9 f t 3 - 9 f t

E 0.230 0.081 - 0.62 0.131 - 0.621

S 1.94 i n . 0.500 - 3.00 in . 0.500 - 3.00 in .

TABLE 24. Net Exponents Used by Bai 1 l i e , Smoot and Babb, and Thornton

N e t Expanent

Var iab le B a i l l i e Smoot and Babb Thornton Comment

t o . 79

-0.66

-0.26

+O. 30

-0.1 7

-0.72

-0.72 - (VC, VD i n f l o o d i n g capac i t y )

The comparison does i l l u s t r a t e t he dilemma one faces i n t r y i n g t o choose

a s u i t a b l e equat ion t o p r e d i c t f lood ing .

M c A l l i s t e r and Ryon suggest t he fo l l ow ing as a c o r r e l a t i n g method.

Th i s equat ion cou ld be compared q u a n t i t a t i v e l y w i t h t h e ones above. The

dens i t y term u s i n g pave, which i s a f unc t i on o f t h e hold-up, x, cou ld probably

n o t be used s ince the re i s l i t t l e experimental da ta repo r ted which g ives

values f o r x a t f l ood ing . See Table 25 fo r nomenclature. Thornton g ives

an equat ion which r e l a t e s x a t f l o o d i n g t o the f low r a t e r a t i o VD/VC, b u t

t he re i s evidence t h a t t he equat ion may n o t be u n i v e r s a l l y t r u e .

2.5.12 Long i tud ina l M ix ing of t he Continuous Phase

Long i tud ina l mix ing of t he cont inuous phase a t several pu lse f requencies

and volume v e l o c i t i e s were measured by Sehmel. The t e s t s were c a r r i e d

i n t h e same column descr ibed i n Sect ion 2.5.11. It was determined t h a t :

t h e maximum l o n g i t u d i n a l mix ing occurred a t t he t r a n s i t i o n pu lse f r e -

quency, i .e. , t he pu lse frequency a t which column opera t ion changes

from m i x e r - s e t t l e r t o emulsion-type operat ion,

t h e e f f e c t o f d iscont inuous phase f l o w r a t e was unclear,

t h e t r a n s i t i o n frequency, hundredth value stage, was i n v e r s e l y

p ropo r t i ona l t o t h e cont inuous phase v e l o c i t y .

Back-mixing equat ions were bo th mixer s e t t l e r and emulsion type

operat ion. These were:

M i x e r - s e t t l e r opera t ion

Emulsion opera t ion

3 2 E = 6.97 - 9.08 x lo- ' Vc ( f - f n ) + 0.166 Ap - 4.8a + 2.49a 2

where:

Vc = continuous phase v e l o c i t y , f t l h r

f = pu lse frequency, cyc lmin

IT = pulse frequency a t t r a n s i t i o n p o i n t , cyclmin

Ap = d i f f e r e n c e i n phase dens i ty , 1 b / f t 3

a = pu lse ampli tude, i n .

TABLE 25. Nomenclature for Ryons Connotation

a,, al, a2 . . . etc. = constants

A = pulse amplitude i n the colurm from the bottom of

the st roke t o the top of the st roke ( f t )

d = diameter o f per forat ions ( f t )

ds = outs ide diameter of the spacer ( s ) between the

p la tes ( f t )

D = ins ide diameter o f colunm ( f t )

F = pulse frequency (cyclmin)

g = the loca l accelerat ion o f g r a v i t y ( f t / h r z )

n = number of per forat ions per p l a t e

S - p l a t e spacing, the d istance from the top face o f

a given p l a t e t o the bottom face o f the p l a t e

above ( in . o r f t ) .

Vc = v e l o c i t y o f the continuous phase ( f t 3 / h r ) ( f t z

colunm cross-section less cross-sectional area

o f spacers) ( n e t u n i t s f t l h r )

VD = v e l o c i t y o f the disperse phase ( f t l h r )

y = i n t e r f a c i a l tension between the continuous and the discontinuous

phase (dynlcm)

AD = same flow quan t i t y as for TID. bu t averaged as a r a t e over the

e n t i r e pulse cycle, as i n f t l h r . For a s ine wave pulse

= FAe(A) + Vp(A)

uc = absolute v i s c o s i t y o f the continuous phase ( l b l f t h r )

uD = absolute v i s c o s i t y o f the disperse phase ( l b l f t h r )

vC = kinematic v i scos i t y of the continuous phase =

VD = kinematic v i scos i t y o f the discontinuous phase = uD/oC

n = 3.14.16 ... TIave = average flow r a t e of both phases i n both d i rect ions, i.e., an

average of nD and IIC over the appropr iate time i n t e r v a l s BD and

Bc

nc = average f low r a t e o f the t o t a l mater ia l past the p la tes i n the

d i r e c t i o n of the continuous phase flow, averaged over the actual

t ime o f f l ow i n tha t d i rec t ion . as i n f t l h r = r = T - A V

fo r a s ine wave pulse

'ID = average f low r a t e of t o t a l mater ia l past the p lates i n the

d i r e c t i o n o f the discontinuous phase flow, averaged over the

actual t ime of f l ow i n tha t d i rec t ion , as i n :t/hr =

% + LV for a s ine wave pulse

l o - 1 % - oDI, the absolute value of the densi ty d i f ference of the

phases (1 b / f t 3 )

nave = average densi ty o f both phases = pC + (pD - pC) x, where hold-up

i s uni form throughout

= densi ty o f the continuous phase ( l b / f t 3 )

3 OD = densi ty of the discontinuous phase ( l b l f t )

if = maximum f r i c t i o n a l power absorbed per u n i t mass of f l u i d i n

the perforat ions i n the sieve plates, f t Z / h r 3 =

f o r a s ine wave pulse. ZE CO L

2.5.13 E f f e c t o f Operat ing and Design Parameters on Column Throughput

A study cons ider ing 20 chemical systems and 2200 data p o i n t s f a i l e d t o

produce a s i n g l e unique equat ion t h a t i s b e t t e r than any o the r equat ion.

The equat ion below was p r e f e r r e d by ~ r o n i e r ( ~ ~ ) t o p r e d i c t f l o w capac i t i es

w i t h an average e r r o r o f 8.56% (p red i c ted value h igh by t h i s amount). I t

g ives approximately t he proper shape over t he e n t i r e range o f f 1 ooding.

where

A = pu lse amp1 i tude ( i n . ) , o v e r a l l f o r e n t i r e pulse s t roke

d = pu lse-p la te ho le o r p e r f o r a t i o n diameter ( i n . )

S = pulse p l a t e spacing ( i n . )

y = i n t e r f a c i a l tens ion (dynlcm)

A, = average f l o w r a t e o f a l l ma te r i a l pas t the pu lse p la tes

i n the d i r e c t i o n o f t h e continuous-phase f low, averaged

over t h e e n t i r e pulse cyc le ( f t / h r )

AD = average f l o w r a t e o f a l l ma te r i a l pas t the pu lse p la tes

i n the d i r e c t i o n o f t he dispersed-phase f low, averaged

over t h e e n t i r e pu lse cyc le ( f t / h r ) 3 Ap = abso lu te dens i ty d i f f e rence between phases ( l b m / f t )

E = f r a c t i o n a l f r e e area o f t h e pu lse p l a t e s

'-' c = v i s c o s i t y o f continuous phase (cP)

5.l = RMS o f rc and nDY nM = \I- ( f t / h r )

IT,, = average o f n and ITD, IT,, = 0 .5( rD + IT^) ( f t / h r ) C

pc = d e n s i t y o f continuous phase ( g l c c ) .

2.5.14 Flooding Def in i t ion

A pu lse column was opera ted by McNamee ( 7 6 ) t o i n v e s t i g a t e f looding .

He developed a method f o r determining t h e f looding r a t e of a pulsed column

by p l o t t i n g measured so lven t hold-up a s a funct ion of aqueous feed r a t e .

The c o r r e l a t i o n i s a l i n e a r func t ion through the o r i g i n . Thus, a p o s i t i v e

dev ia t ion from t h e s t r a i g h t l i n e c o r r e l a t i o n i s one c r i t e r i o n of f looding .

The second c r i t e r i o n of f looding i s so lven t hold-up; s t e a d y - s t a t e hold-

u p i s l i n e a r w i t h t ime. When f looding occurs hold-up inc reases with t ime.

The r a t e of accumulation o f f e r s a means of back c a l c u l a t i n g from t h e

uns teady-s ta te ( f l ood ing ) opera t ion t o t h e r a t e and corresponding hold-up

a t which f looding began.

2.5.15 Dispersed-Phase Hold-up Cor re l a t ion

Based on t h e r e s u l t s obtained i n a 2-in. diameter column conta in ing

s t a i n l e s s s t e e l p l a t e s having 0.125-in. diameter ho le s , 23% f r e e a r e a , and

2.2- in. spac ing , Bell found t h a t a x i a l d i s t r i b u t i o n of hold-up ac ros s a

column was e s s e n t i a l l y cons t an t with r e s p e c t t o column he ight . However,

t o t a l f r a c t i o n a l hold-up increased from l e s s than 0.1 a t low pulse f r e -

quencies t o 0.4 a t pu lse f requencies of 160 t o 180 cycleslmin. (10)

Hold-up can be c o r r e l a t e d a s fol lows:

VY E = - [E + (1.25 x + 2.42 x 1 0 ' ~ V X ) ( a f - 28.2

where

VY = s u p e r f i c i a l water v e l o c i t y , f t l h r

VX = supe r f i c ia1 hexane o r methyl i sobutyl ketone v e l o c i t y , f t / h r

a f = pulse amplitude times pulse frequency, in./min

E = 0.03 and G = 64 f o r hexane

E = 0.05 and G = 38 f o r methyl i sobuty l ketone.

2.5.16 Dispersed - Phase Holdup C o r r e l a t i o n

The to1uene:water system was used by ~ i s h r a ( ~ ' ) i n a pu lse column

having the f o l l o w i n g c h a r a c t e r i s t i c s :

i n s i d e diameter of column: 7.62 cm

p l a t e spacing: 5 cm, 10 cm

p l a t e ho le diameter: 0.476 cm, 0.635 cm

f r e e area o f pe r fo ra ted p l a t e : 22.6%, 36%

p l a t e th ickness: 1/16 x 2.54 cm

dispersed-phase fl ow-rate: 0.08 t o 0.25 cm/sec

continuous-phase f l o w ra te : 0.08 t o 0.27 cm/sec

pu lse v e l d c i t y : 0.834 t o 3.03 cm/sec

He made the f o l l o w i n g conclusions.

Dispersed phase hold-up increases w i t h t h e increase of d iscont inuous

phase f l o w r a t e and i s independent o f t he f l o w r a t e o f continuous

phase.

A t a g iven value o f o t h e r va r i ab les , hold-up i s increased w i t h the

increase o f pu l se v e l o c i t y .

Hold-up decreases w i t h t h e increase o f t he hole-diameter, percent

f r e e area, and p l a t e spacing.

* Wi th in the range o f va r i ab les studied, t h e present hold-up data has

been c o r r e l a t e d by an emp i r i ca l equat ion:

where the constant K i s equal t o 3.66 f o r t h e toluene-water system

and

Vp = pu lse v e l o c i t y , cm/sec

L = p l a t e spacing, cm

R = f r a c t i o n a l f r e e area

FD = s u p e r f i c i a l v e l o c i t y of d ispersed phase, cmlsec

d = hole diameter, cm.

2.5.17 Parameters Important to Extraction Efficiency

spaay(lo3) presents data from 2 , 4, and 9-in. diameter column t e s t s t o demonstrate that d r o p diameter, hold-up of the dispersed phase, axial mix ing , coeff ic ients , and mass t ransfer i n pulse packed column are of essen- t i a l importance to extraction efficiency.

2.5.18 Effects of Operating and Design Parameters on Column Capacity and Efficiency

Rouyer (") tested loo-, 300-, and 600-mm diameter pulse columns and made the following conclusions.

The flooding curves for each diameter were nearly identical.

W i t h a fixed plate f ree area and hole size,the throughput increased

w i t h an increase in plate spacing.

Plate f ree area did not have a large ef fec t on column efficiency. Plate spacing has a greater e f fec t on column efficiency than plate

f ree area. HTU values vary considerably along the column height. For example, an HTU between the aqueous feed point and 0.5 m below was 27.5 cm, b u t

between the feed point and 1.5 m below the HTU was 60 cm.

An equation relating column capacity to s l i p velocity ( the re la t ive drop velocity w i t h respect to the continuous phase) was developed.

2.6 VALVE ACTUATED PULSE COLUMN

A valve-actuated pulse column as described by Burger (18919) i s a

counter current extraction column which employs timed solenoid valves and pressurized feeds to provide a pulsing action to disperse the phases. The steps i n the pulsing cycle are independent and, thus, provide greater separation of the operating variable than i s possible w i t h a conventional pulse column.

HETS values of 7 t o 8 i n . were obtained from t e s t s carried out in a 1-in. diameter column under Purex extraction conditions with dual faced plates (fluorothene--stainless s teel having the plast ic side down) which had 0.026-in. diameter holes, 15.5% f ree area and 2-in. spacing. Using the

same p la tes and configuration, HETS values of from 8 t o 8.5 i n . were obtained

f o r s t r ipping. I t can be concluded t h a t the pulsing was producing a good

dispersion.

Burger conducted a more de ta i l ed study of the valve-actuated column

under Purex s t r ipp ing column conditions. (20) The organic phase consisted

of 30% TBP i n AMSCOy and contained 200 g / ~ uranyl n i t r a t e and 6 t o

8 g la n i t r i c acid. D i s t i l l ed water was used as the s t r ipp ing phase. Four

type p la tes were used a s shown i n Table 25a.

TABLE 25a. P la te Design Data

Hole Diameter , Open

i n . Area, % Facing Type

0.039 9 Double, f l uorothene-- 0.026 15.5 s t a i n l e s s s t e e l 0.020 2 3 Sta in less s t e e l , Kel-F

S lo t s 3/16 x 0.014 9 coated on one s i de

The p la tes were oriented i n the column so t h a t the r i s i ng organic phase

s t r i k e s the organic-wetted fluorothene and the f a l l i n g aqueous phase s t r i k e s

the water-wetted s t a i n l e s s s t e e l surface. Burger used 1/2-, I - , and 2-in.

p l a t e spacings and a column temperature t h a t varied between 25 and 65°C.

Pla tes having 0.02-in. diameter holes, 112-in. spacing, and 23% f r e e area (Kel-F) gave the lowest HETS values ( 2 t o 4 i n . ) . He concluded t ha t :

By increasing the operating temperature, a g r ea t e r ext ract ion eff ic iency

i s achieved. T h i s i s t r ue even when accompanied by an adverse equi l ib-

rium s h i f t . '

A decrease i n p l a t e spacing improves extract ion e f f i c iency , b u t a l so

lowers t he maximum flow r a t e through the column.

A decrease i n p l a t e hole s i z e increases ef f ic iency by producing a

be t t e r dispersion of smaller drops. High flow r a t e s can be maintained

even with 0.020 in. diameter holes.

E x t r a c t i o n e f f i c i ency increases w i t h frequency. With t h e apparatus

descr ibed the upper frequency i s l i m i t e d t y t h e i n t e r f a c e c o n t r o l .

Increased temperature f a c i l i t a t e s ope ra t i ona l c o n t r o l o f t h e column

and a t the same t ime permi ts opera t ion a t h ighe r frequencies and f l o w

r a t e s due t o more r a p i d d i spe rs ion and coalescence.

2.7 PHASE REDISTRIBUTION

Uranium e x t r a c t i o n s tud ies were being c a r r i e d o u t i n a 23.5-in. d iameter

column con ta in ing 23% f r e e area s ieve p l a t e s , having 0.125-in. diameter holes

and a 2 - in . spacing. R e d i s t r i b u t o r p l a t e s were i n s e r t e d a t 14, 40, 80 and

120 i n . below the t o p of t h e 13 .5- f t p l a t e sec t ion . A 6- in . p l a t e - f r e e

space was l oca ted above and below each d i s t r i b u t o r . The r e d i s t r i b u t o r

p l a t e s had 2- x 7 - in . ba f f led openings l oca ted 2 i n . from t h e o u t e r edge o f

t he p l a t e s and spaced a t 0, 90, 180, and 270" around the circumference.

Baff led openings 2 x 2 i n . were l oca ted between t h e l a r g e r openings. A f t e r

i n s e r t i o n , t h e column waste losses dropped from 6 t o 0.001%. (129)

AUTOMATIC CONTROL OF A PULSE COLUMN

A c o n t r o l system t o min imize p lutonium l o s s from a nuc lea r separat ions

p l a n t s o l v e n t e x t r a c t i o n column i s descr ibed by Atwood. ( 3 ) 1 t uses magnetic

f l o w meters f o r t h e aqueous streams, e l e c t r o n i c d i f f e r e n t i a l pressure

c e l l s f o r mon i to r i ng t h e organic streams, and neutron count ing devices f o r

measuring p lu ton ium concent ra t ion . I n d i v i d u a l components o f t h e systeni have

been demonstrated on a p i l o t - p l a n t bas is .

2.9 REVIEW PAPERS

The r e s u l t s obta ined f rom t e s t i n g pu lse column i n t e r n a l s i n a 3- in .

d iameter column under Purex p l a n t cond i t i ons a re g iven by Sege. (96)

The p l a t e s t e s t e d had t h e fo l l ow ing geometry:

Hole diameter: 0.06 t o 0.1875 i n .

Free area: 10 t o 40%

P l a t e spacing: 1.4 t o 4 i n .

Both fluorothene and s ta in less s teel plates a re included, and the direction of t ransfer was from aqueous to organic and vice versa.

- . HTU values were found to be i n the range of 0.7 to 1.5 f t and 1. were unaffected by wall clearance when i t was between 0.015 t o

. . 0.124 in. , 2. decreased w i t h increasing pulse amp1 i tude times pulse frequency

product near the flooding point, 3. were insensit ive to throughput rate during emulsion type operation, 4. increased with increasing continuous-to-dispersed phase flow r a t i o , 5. were higher when the plates a re wetted by the dispersed phase, 6. were generally unaffected by plate spacing, 7. were very sensi t ive to plate geometry, i . e . , hole s ize and/or f ree

area, 8. were generally higher a t the d i lu t e end of a column, and 9. were unaffected by column diameter between 3 and 8 in.

A variety of pulse column internals and the i r operating character is t ics are described by ~ e i e r ( ~ ~ ) with respect t o the i r u t i l i t y i n the principal contactors of a Purex solvent extraction battery. The column internals discussed include:

s ta inless s tee l sieve plates of the geometry equally spaced, s ta in less s teel sieve plates of different geometries and unequal spaci ng , f 1 uorothene sieve plates , mixed fluorothene and s ta in less s teel sieve plates , fluorothene Raschig rings, and s ta in less s teel Raschig rings.

The examples described demonstrate tha t 4 pulsed solvent extraction column can be ta i lored, by proper design of the column internals , t o pro-

duce the desired capacity, efficiency, choice of continuous phase, and rangeabil i t y for a given system.

The s ieve p la te geometry, HTU, pulse power, and back-mixing a r e

included i n a paper by Richardson. (87) I t i s shown i n t h i s paper t h a t the capacity of a pulse column i s proportional t o . .

where

AP = density difference between the phases

y = i n t e r f ac i a l tension

pC = viscos i ty of the continuous phase.

Also mentioned i s t he f a c t t h a t Mistron (a f i n a l l y divided t a l c ) in a con-

centra t ion of 50 pprn g rea t ly increases the coalescing tendency of the d i s -

persed phase and reduces the disengaging time of an equal volume of water

and 30 vol% TBP in kerosene from 60 t o 15 sec.

Duc kworth (46) presents an overview of Purex reprocessing plant tech-

nology i n which pulse columns, pumps, and in te r face control devices a r e

discussed.

2.10 OTHER PULSE COLUMN APPLICATIONS AND DESIGNS

2.10.1 Pulse Column f o r Removal of Hafnium from Zirconium

Jasny (64 ) used a 1.5-in. diameter pulse column, 9.5 f t high, t o remove hafnium from zirconium. Platinum p la tes having 19% f r ee a rea , 0.043-in.

diameter holes and a 1-in. spacing comprised the column in te rna l s . The

colunin was shown to be equivalent t o six mixer-se t t ler s tages. I t was

a l so found t h a t

increasing t he pulse frequency from 55 t o 90 cycles/min increases

product pur i ty , increasing the pulse amplitude t o a point where the surge carr ied

through two pla tes ra the r than one increases e f f i c iency , and

increasing the t o t a l throughput decreases ef f ic iency.

The b e s t r e s u l t s (HETS = 2.5 f t ) were ob ta ined with a pu l se frequency of 55 cycles/min, a pu l se ampli tude of 1.25 i n . , and a volume v e l o c i t y of 660 g a l / h r / f t 2 .

2.10.2 Rotat ing Paddle Ex t r ac t i on Column

. . An e x t r a c t i o n column having a r o t a t i n g paddle between s o l i d p l a t e s of f l uo ro thene o r s t a i n l e s s s tee l , which provide free a rea a t a1 t e r n a t e s i d e s

of the column,had a pu ls ing a c t i o n imposed on the column con ten t s . The column s p e c i f i c a t i o n s and the r e s u l t s ob ta ined by ~ i ~ ~ , ( ~ ~ ) from tests using Purex e x t r a c t i o n and s t r i p p i n g column ope ra t i ons a r e shown i n Table 26.

TABLE 26. Purex 1A Column and 1C Column Rota t ing Paddle T e s t s ( a )

Run Data 1A Column 1 C Column

, Run Number Feed conc. , g , UNH/1 (uni rradi ated) Waste conc. , g , UNH/1 Volume velocity, gal/(hr) ( f t Z ) Pulse frequency, cyc/mi n Pulse amp1 i tude, in. Agitator speed, rpm Aqueous--organic volume ratio, L / V Number of transfer units HTU, in. umber of theoretical stages HETS, in. stage efficiency , percent Duration, h r

Column Specifications

Overall column length, in. 12 12 Cartridge 1 ength, in. 5.75 6.75 Column . ., in. 1 .O 1 . O Agitator section length, in. 0.5 0.5 Settling section length, in. 0.5 1.0 Number of mechanical stages 6 5

(a) Notes: 1. Impellers in Run 1 .did not have the radial holes. 2. Plates in Run 1 were al l fluorothene; in Run 2 the bottom plate was

fluorothene and alternate plates were stainless steel. 3. The f i r s t half hr of Run 1 was made w i t h the column inclined 30 degrees

from the vertical ; the la t te r with the column 15 degrees from the horizontal. 4. Run 2 was made with the column mounted vertically. 5. Column condi t i ons--Purex Flowsheet.

Pulse Column for Processing STR and SIR Fuels

Tests on the processing of STR and SIR fuel with 10 vol% TBP in AMSCO

were carried out in a 2-in. diameter column by Friederichs. The extrac- . . tion column internals consisted of 23% free area stainless steel plates having 0.125-in. diameter holes, spaced 2 in. apart. Uranium concentration in

the feed ranged from 0.01 to 0.0016M. - High concentrations of other salts particularly aluminum and fluoride were also present. At a pulse frequency

of 85 cycles/min, an aqueous-to-organic flow ratio of 4.5, and a volume 2 velocity of 800 gal/hr/ft HTU val-ues as a function pulse amplitude are

listed in Table 27.

TABLE 27. HTU Values

Pulse Amplitude, in. HTU, ft

2.10.4 Pulse Columns - General Observations The methyl isobutyl ketone:acetic acid:water and 10% methylene

dichloride in ethyl acetate:acetic acid:water systems were used by Chantry (26) for testing both pulsed packed and pulsed sieve plate columns.

In a 27-in. high, 1.57-in. diameter column packed with 1/4 by 1/4-in. Raschig rings, HETS values were between 3.5 and 8.4 in. When sieve plates

(3/64-in. diameter holes and 6% free area or 5/64-in. diameter holes and

10% free area) were used in the same column on a 1-in. spacing, HETS values

from 4 to 19 in. were obtained.

He concluded for pulsed packed columns that:

The application of pulsation to a packed column is a practical way to

improve efficiency. Packed height may be reduced by a factor of three

and give the same resul ts.

O p t i m u m operating conditions can be obtained by varying e i t h e r pulse

amplitude o r pulse frequency.

Greater ef f ic iency can be obtained with low pulse amplitude and high

pulse frequency than vice versa. The maximum throughput is reduced s l i g h t l y when the column i s pulsed.

Changes i n feed r a t e s have l e s s e f f ec t on column eff ic iency when

pulsing i s used.

For ' ~ u l s e d s ieve p la te columns i t was concluded t ha t :

Sta es Average p la te e f f i c ienc ies (Number o; Plates ) as high as 70% can be

obtained. Pulsed p la te columns have high throughput r a t e s compared t o packed

col umns. Smaller p la te perforat ions a r e more e f f i c i e n t , b u t they have lower

capacity and may e i t h e r erode o r clog.

2.10.5 Column f o r Recovery of Uranium from Dilute Waste Solutions

The use of a 15 f t high by 1.25-in. diameter pulse column t o recover

uranium from waste solut ions (60 t o 80 ppm uranium) is disccused by

Webb. The p la tes contained 0.045-in. diameter holes and were spaced

1 i n . apar t . The r e su l t s showed:

HETS values of 5.5 t o 12.5 f t were obtained.

No systematic va r ia t ion of HETS values with flow r a t e were obtained.

A concentration of uranium in the waste stream as low as 0.04 ppm

was obtained.

2.10.6 Effects of Operating and Design Variables on Pulse Columns

Using a pulsed column having a 1.57-in. diameter and the uranyl

n i t r a t e : n i t r i c acid system 40 vol% TBP i n kerosene, Durandet (47) inves t i -

gated the e f f e c t of perforated p l a t e hole s i z e during the re-extraction

s tep . The pla tes had 23% f r e e area , 1.96 in. spacing, and e i t h e r

0.079-in. o r 0.118-in. holes. He found t h a t w i t h the organic phase d i s -

persed 0.118-in. diameter holes gave HETS values of 6 in . a t a pulse ampli- . . tude frequency product of 60 in . m i n . HETS values about 50% lower were

. .

obtained with the smaller holes. For an aqueous dispersed system with a

0.118-in. hole diameter the efficiency was not a function of volume velocity,

the capacity of the column was about half that obtained with the organic . -

phase dispersed, and the lowest HETS values were obtained a t a pulse ampli-

tude times frequency product of 60 in./min.

Using the same column with plates having the larger hole s ize , extrac-

tion studies showed that when the organic phase i s dispersed the product

of pulse frequency times amplitude does not provide a useful comparative

tool , HETS values do not appear to be a function of pulse amplitude, and the lowest HETS value (13 in . ) occurs a t a pulse amplitude times frequency

product of 100 in./min. If the aqueous phase i s dispersed during extraction

the column capacity i s reduced by 50%.

2.10.7 Column Capacity in a Radiochemical Plant

Redon (84) concludes that the pulse columns in a radiochemical plant

should be designed t o process the anticipated natural uranium throughput

when operating a t 50% of capacity. Thus, the plant processing limitations

imposed when handling enriched uranium will not unduly r e s t r i c t processing

capacity.

2.10.8 Removal of Thorium from Uranium in the Scrub Section

Tests were carried out by ~ehmoiras(') in a 2.16-in. diameter pulse

column to determine the degree that thorium could be removed from uranium

in a scrub section. The column internals consisted of 23% f ree area s tain-

less s teel sieve plates having 0.11-in. diameter holes and a 1.97-in. spacing. A pulse amplitude of 0.79 in. and a pulse frequency of 150 cycles/

min were used. .

The efficiency of thorium removal was found to be equivalent to

theoretical u p t o uranium concentrations of 116 g / a . A t higher concentra-

t ions a dramatic reduction in thorium decontamination occurs. Probable

causes of the decontamination behavior are theorized to be:

High uranium concentration in the organic phase increases the viscosi- t ies of bo th phases which may decrease the diffusion velocities involved. A decrease in the degree of dispersion occurs with a decreasing

concentration of free TBP.

The concentration of free TBP interferes with thorium re-extraction t o a greater degree than in the case of uranium re-extraction.

The concentration of free TBP interferes with thorium re-extraction

t o a greater degree than in the case of uranium re-extraction.

2.10.9 Eurochemi c Pulse Column Battery

The pulse column battery for the Eurochemic separations plant a t Mo1 , Belgium i s defined by de ~ i t t e ( ~ O ) and Joseph. (69) The pertinent

features of the columns are given in Table 28.

TABLE 28. Pertinent Column Features

Pu1 s e Pulse Flood Continuous Diam. Cartridge k p l i tude, ~ r e ~ u e n c y . ~ a p a c i t3 HETS.

Column Purpose Phase . .

in . - Type in . cycles/min g a l / h r / f t ft HA Extract Organic 5.9 Nozzle 0.98

HS Scrub . Organic 5.2 Nozzle 0.98 60 580 2.3

1BX P a r t i t i o n Aqueous 3.95 Sieve 0.79

1BS Scrub Aqueous 1.96 Sieve 0.98 60 780 2.3 plates(')

1C S t r i p Aqueous 5.9 Nozzle(,) 0.49 P la tes

2D Extract Organic 5.2 Sieve 0.98 PI a t e s ( a )

2E S t r i p Aqueous 5.2 Nozzle ' 0.49 PI a tes (a )

(a) Hole Diameter = 0.138 in . , Free Area = 22.5%, P la te Spacing = 1.96 in . Hole Diameter = 0.138 in . , Free Area = 11.0%, P la te Spacing = 1.96 i n . Hole Diameter = 0.118 in . , Free Area = 22.5%, P la te Spacing = 1.96 in .

( d ) Hole Diameter = 0.189 i n . , Free Area = 32.5%, P la te Spacing = 3.92 i n .

2.10.10 Eurochemic Pulse Column Operating Characteristics

Several pulse column cartridge configurations were evaluated for use

in the Eurochemic plant HA-HS columns and the resu l t s are reported by . . de ~ i t t e . (42) The evaluation led to the selection described above. Data were accumulated on several off-standard f i r s t cycle pulse column operat-

ing conditions and the time required fo r detection through plant performance.

The sa l ien t observations are l i s t ed in Table 29.

TABLE 29. de Witte Observations

Inc iden t

Sudden increase o f 15% i n HA column feed r a t e

Sudden decrease o f 10% i n HA column ex t rac tan t r a t e

Sudden decrease o f 20% i n HS column scrub f low

Sudden 25% decrease i n pulse ampl i tude

Sudden 50% decrease i n pulse ampl i tude

Temperature increase 50 t o 70°C

Time t o Detect, m i n

D i f f i c u l t t o detect

2.10.11 Re-extraction of Uranium from TBP

~ a v e n d i s h ( ~ ~ ) investiga-ted the re-extraction of uranium from 33.5 vol%

TBP in kerosene containing 100 g uraniumla. Stainless s teel sieve plates ,

stain1 ess s teel nozzle plates , and dual faced plates (fluorothene/stainless

s teel ) were tested. Capaci ty-efficiency resul ts obtained with the organic

phase continuous are given in Table 30. Other observations drawn from the

data include;

throughput i s a d i rec t function of pulse power,

t ransfer efficiency was improved by increasing the temperature to

150°F,

uranium t r a s n f e r was improved by adding ammonium hydroxide a t t he

p o i n t where the uranium concentrat ion was 40 g la, and

t h e best c a r t r i d g e would cons is t o f s ieve p l a t e s i n the bottom two-

t h i r d s and nozzle p la tes i n t h e top one-th i rd.

TABLE 30. Cavendi s h Resul t s

Maxi mum uranium Conc. Stage Throughput, in Raffinate, Efficiency,

Plate Type gallhr-ft2 sla %

Sieve 1550 0.02 79 to 91 Nozzle 1880 0.3 75 to 83 Dual -Faced 1510 0 .2 82 to 91

3.0 MIXER-SETTLERS

MIXER-SETTLERS

The mixer-settler i s a countercurrent contacting device consisting of a ser ies of stages in which mixing i s accomplished by the mechanical action

of a variable speed impeller and the phases a re separated by gravity. There

a re many variations possible in the design of mixer-sett lers, b u t the prin-

cipal difference i s the method by which hydraulic s t a b i l i t y i s achieved.

Some methods tha t have been used are:

1. vertical arrangement of the stages,

2. horizontal arrangement, b u t varying the levels of the stages,

3. regulating flow between stages by valves or adjustable s l o t s , and

4. horizontal arrangement, using a pump-mix impeller to provide the

required flow for the heavy phase.

3.1 SAVANNAH RIVER CONTACTORS

3.1.1 Mixing Capabilities

A heat balance was used by Mottel (79) t o measure the mixing capabili ty

of a mixer-settl e r unit . An aqueous-to-organic (water-to-kerosene) f l ow

ra t io of 1.66 was used in a l l t e s t s . Impellers tested were composed of

a shroud having a 1-1/8 in. diameter and 2 , 4 , or 6 blades tha t were 1-in.

diameter, 1/8 to 3/8 in. high. ' He found that :

Mixing efficiency increased with paddle speed. The efficiency was

best with a four-bladed paddle and when a r a t i o of shroud height to paddle height of two was maintained.

The suction head increased with an increase in the number of blades

or an increase in blade height.

The following correlation could be made:

A a L ~ * ~ N

where

A = interfacial area generated by a f l a t paddle

N = paddle speed

L = paddle diameter

Stage eff ic iencies as h i g h as 99%

3.1.2 Hydraulic Characteristics of Mixer-Settler Impellers

In a study of the hydraul i c character is t ics of mixer-settl e r impellers,

Webster 25) found tha t the impeller behaved 1 ike a low-head pump, and was

not affected by recirculation from the mixing to the suction sections.

In the range of 250 to 450 rpm the variables could be correlated by:

where

H = head, in .

q t = flow through impeller, gpm

N = impeller speed, rpm

I t can then be observed that : 1 ) with no head, capacity i s proportional to

impeller speed, and 2 ) with no flow, head i s proportional to the impeller

speed squared. Other observations included:

The discharge coefficient fo r flow through the recirculation annulus

decreased with increased annulus area. The relationship a t an impel1 er

speed of 345 rpm i s shown in Table 31.

Head and flow increase with impeller speed fo r a given s ize recircula-

t i on hol e.

Head-capacity character is t ics of the impeller are independent of rec i r -

culation r a t io .

TABLE 31. Relationship a t an Impeller Speed of 345 rpm

D i scharge Annul us Coefficient Area, in.2

0.8 0.64

3.1.3 Operating Characteristics - Three-Stage Mixer Se t t l e r

Using the uranium n i t r a t e - 30 vol% TBP i n Ultrasene system, Colvin (27 1 tested a three-stage mixer-settler. Each stage had a 13.5-in. mixing length

and a 9-ft s e t t l i ng length. The units were 1 f t wide by 1 f t deep. A t an

aqueous-to-organic flow ra t io of 1.5, extraction was increased from 35 t o 90% by increasing the impeller speed from 200 t o 500 rpm. The pressure

drop of the 1 ight phase was found t o be 1.3 in. per stage a t a flow r a t e of

45 gpm. I t was observed tha t the pressure drop increased w i t h flow ra t e

and impel l e r speed. Operating character is t ics could be changed by varying

impeller design, i . e . , using an impeller w i t h a greater width or with

blades on the periphery, improved extraction a t the same throughput.

3.1.4 Critically-Safe Mixer Se t t l e r

The design of a c r i t i c a l l y safe mixer-settler 3 in. high by 8 in. wide

by 5 f t long i s described by Colvin. The uni t , which used a 4-112 in.

diameter f l a t impeller paddle capable of speeds u p to 700 rpm, had s ix stages and showed an extraction efficiency of 80%. The document also

describes a c r i t ica l ly-safe shrouded paddle ag i ta tor for use in a 7.5-in.

diameter vessel . 3.1 .5 Mixing Efficiency in a Three-Stage Mixer Se t t le r

Heat t ransfer between water and ultrasene was used in a three-stage

mixer-settler uni t in which each stage had a 3-in. wide by 1- f t high mixing

zone t o determine mixing efficiency. A number of paddle and shroud con-

figurations ( a l l 1 -in. diameter) were tested by Mottel . (801 Paddle speed

was varied by a factor of two.

The heat t ransfer could be correlated by the following equation:

in which

UA = heat flow, B t u l m i n - O F

L = paddle diameter, f t

N = paddle speed, rpm

Vm = mixing volume, i n . 3

3.1.6 Mixer Devices - Pump-Mix Mixer-Settler

The testing of mixer designs was continued by ~ a v i s ' ~ ' ) who tested the

mixing devices in a single stage of a pump-mix mixer-settler. The stage was a long rectangular box, 15 in. h i g h and 8 i n . wide that was divided into two parts: an 8-in. long mixing section and a 48-in. long settling

section.

The mixing efficiency of the various impellers was determined by a

heat transfer technique. The difference in temperature of the two phases af ter mixing compared with the temperature difference before mixing was used as a measure o f how efficiently the two phases had been contacted.

The effectiveness of various impellers was compared a t constant t i p speed in a single stage of a mixer-settler. Rather than use power i n p u t

a heat conductance was determined from a heat-balance model w i t h para1 1 el flow assumed. A comparison of impellers shows that higher efficiencies were produced by open impellers (paddles and propellers) than by closed impellers (centrifugal and disk impellers) a t the same t i p speeds, a t which speeds approximately the same amount of dispersion was produced by a l l types. The paddles tested and the conditions used are summarized in Table 32 and the following subsections.

TABLE 32. Impel 1 er Efficiency Tests

Mixer Type

Open paddlesCa)

Simple Paddle

Pitched Paddle

Marine Prope l le rs

Turbine

Closed Prope l le rs

Diam, Height, Speed, Total low!^) i n . i n . -- Des i qn revlmi n gPm

2 7 1 8 , 1.2 S o l i d a n d p e r - 8 0 t 0 2 5 0 4 t o 1 7 . 5 5 fora ted blades

4 2 Two opposi te- 100 t o 300 13.4 30' t h rus t paddles,

P i t ch 1 i n . apar t

5 1 Two opposite- 150 t o 450 4 t o 16 t h rus t paddles, back t o back

5 1-112 (See Figure 3) 170 t o 260 15.4

Cent r i fuga l Impel l e r 5 1/2.1 S ing le suct ion, 130 t o 400 4 t o 16

w i t h and wi thout blades o r caps

1 Double suct ion

Disk 3.5 1.1, S i n g l e s u c t i o n 1 5 0 t o 8 0 0 13.4 Impel le r 1 /4

1-314

( a ) ~ h e marine prope l le rs have three blades; a l l o ther mixing devices have four ( b ; ~ l o w r a t i o s between 0.25 t o 1 and 0.45 t o 1 except f o r cen t r i f uga l

contactors where the r a t i o was var ied between 0.25 t o 1 and 4 t o 1

Mixing Speed and Flow Variables

Simple Paddles. For the same speed the paddle with the largest facial area gave the highest efficiency as was expected. The efficiency was lower for smaller paddles, for paddles w i t h perforated vanes, and fo r the turbine paddle. About the same amount of dispersion was observed in the se t t l i ng section a t the same t i p veloci t ies . Typical dispersion thicknesses were: 1-112 in. a t 250 revlmin, 1 in. a t 200 revlmin, 112 in. a t 150 revlmin, and less than 112 in. below 150 revlmin. The 2.9-in. diameter paddle gave

112 in. dispersion a t 250 revlmin.

Pitched Paddles and Marine Propellers. Two pitched bladed paddles with opposite thrust were noticeably more e f f i c i en t than the two marine propel- l e r s a t the same t i p velocity. In both cases the efficiency increased with speed. Two propellers spaced 1 i n . apar t on the same shaf t were not as e f f i c i en t as two propel 1 e rs touching. The combination of two propel 1 e rs with a paddle in between was only s l ight ly more e f f i c i en t than the paddle alone. Four propellers on one shaft were no more e f f i c i en t than two. Dis- persion thicknesses a t 13.4 gpm were as high as 3-112 i n . a t 450 revlmin, b u t l e s s than 112 i n . a t 150 revlmin.

Centrifugal and Disk Impellers. In general the closed impellers were less e f f i c i en t than the open impellers a t the same t i p speed. The larger disk impeller was more e f f i c i en t than the centrifugal impeller of the same diameter a t the same flow and mixing speed, as was expected because of i t s greater axial length. - The efficiency of the centrifugal impeller decreased when an o r i f i ce cap was attached to the i n l e t of the suction tube. There was an increase i n efficiency when m i x i n g blades were placed on top of the centrifugal impel 1 e r . The efficiency of a double-suction centrifugal impeller was higher than the single-suction impeller of the same diameter and width presumably because the two phases were forced to mix inside the impeller. Dispersion thicknesses varied between 112 and 1 in. a t 200 rev/

min and between 3 and 3-112 in. a t 430 revlmin.

Correlation of Mixing Efficiency

Effect of Mixer Variables a t Constant Flow. In accordance with the parallel flow equation the mixing efficiency and flow can be represented by UA. The most effective impeller i s the one t h a t produces the highest UA; therefore, the effect of impeller design and speed on UA should be determined. This was done, f i r s t a t constant flow, f o r some of the mixers discussed in preceding sections.

The values of UA for centrifugal and disk type of impellers were correlated against the term llnL

2.5 b0.25 Y

where n = rotational velocity, revlmin L = effective impeller diameter, f t which i s 64% of the actual

diameter for the turbine, and 100% of the actual diameter for a l l other impellers

b = impeller width, f t UA = heat conductance, Btulmin-OF

Effect of Flow on the Correlation. For the closed (centrifugal ) impeller the UA increased in proportion t o the cube r o o t of the flow. For

the open impel lers (paddles and propellers) UA was directly proportional t o the flow. The increase of UA with flow a t constant speed i s most likely due t o the increase in interfacial area which was evident during the runs from a proportional increase in the amount of dispersion.

These flow effects were incorporated into the correlations. The following equations represent the straight-line portions of the curves:

Closed im~el 1 ers :

Open impel 1 ers :

where W = cVp = mass heat flow, Btulmin-OF.

As correlating techniques the effect ive diameter of the turbine paddle was assumed to be 80% of the actual diameter because the vanes did not extend from the axis of the paddle. The effect ive diameter of the propel-

l e r s was assumed t o be 64% of the actual diameter, and 80% reduction because of the rounded blades, and another 80% because the propeller had only three blades whereas a l l the other impellers had four.

3.2 OTHER MIXER-SETTLERS USED FOR RADIOACTIVE SERVICE

3.2.1 KAPL Type

Operating Characteristics - Pump-Mix - Mixer-Settler

Based on the assumptions tha t the mixed phase is uniform in composi-

tion and tha t a l l the aqueous in the mixture leaving a stage s e t t l e s out, avids son(^^) developed an analytical description fo r the hydraulics, impeller operation, and operating character is t ics fo r a pump-mix mixer- s e t t l e r .

Correlation of Operating Characteri s t i c s - Pump-Mi x - Mi xer-Settl e r

Tests were conducted by Coplan (32) i n a 16-s tage mini -mi xer-sett l e r i n which each stage was 3 i n . wide by 11 in. long by 5 in. high using the acidic acid - methylisobutyl ketone - water system. The throughput of the

u n i t was 0.2 to 0.5 gpm which resulted in a residence time of 1 to 2 min. Using an 1 7/8-in. impeller w i t h four 1/4-in. long and 3/16-in. high blades

fastened to the top disk, an extraction stage efficiency of 83% was obtained. When a l i g h t phase baffle was incorporated into the design, stage e f f i - c ies increased to 99%.

The size-capacity character is t ic i s one of the bases for comparison of the relat ive effectiveness of d i f fe rent types of extraction equipment. The volume occupied by the apparatus i s important since space requirements and extractor cost (including packing i f any) would be approximately in proportion to the volume; i f volume i s considered the important s i ze variable, a quantitative measure of the effectiveness of the equipment would be

where Ef = contac tor ef fect iveness

N = number o f t h e o r e t i c a l stages 3 F = t o t a l f low ra te , f t / h r

V = t o t a l contac tor volume, f t 3

t = holdup ' t ime/ theore t ica l contac t ing , h r

tm = holdup t ime i n t h e mix ing sect ion, h r

ts = holdup t ime i n the s e t t l i n g sect ion, h r

K i s a dimensional constant depending upon the so l ven t -ex t rac t i on f lowsheet.

Stage E f f i c i e n c y - 16-Stage Mixer S e t t l e r

Hol mes (601 discusses an extension o f t h e work described above which

was c a r r i e d ou t i n a 16-stage mixer s e t t l e r u n i t . He found t h a t t r a n s f e r

e f f i c i e n c y was a f u n c t i o n o f both r o t o r speed and d i r e c t i o n o f t r a n s f e r

(see Table 33 ) . Above a f low r a t e of 0.3 gpm t h e e f f i c i e n c y decreases i n

a l l cases.

TABLE 33. Trans fer E f f i c i ency

Total Flow, Direction of Rotor Speed, Efficiency, q pm Transfer rpm %

0 - 0.3 A + O 550 100

0 - 0.3 . O + A 550 95

0 - 0.3 A - t O 450 90

0 - 0.3 O + A 450 87

Development of a M in i - M i xe r -Se t t l e r n

Development of t he m i n i -m ixe r -se t t l e r was cont inued by Davidson. (34)

A scale-up procedure f o r the pump-mix m i x e r - s e t t l e r was f i n a l l y developed . . which i s summarized i n the f o l l o w i n g subsect ion.

Settl i ng Section. Scale-up i s general ly effected by maintaining the settling-zone residence-time constant fo r a given system. The min imum

se t t l i ng time i s determined by t e s t s using a pilot-scale u n i t since no simple bench t e s t has correlated with the se t t l i ng time noted under operating conditions. The general shape of the se t t l i ng section i s kept similar t o the p i lo t u n i t . (In actual practice, the height i s usually somewhat less than would resul t from s t r i c t l y geometric simi l a r i ty. )

and i n the larger units, h may equal w. The width i s chosen to be

Mixing Section. The mixing section horizontal cross section remains square w i t h the dimension s e t by the w i d t h chosen above. The impeller

diameter i s the same ra t io of width as in the p i lo t u n i t

The impeller speed i s calculated from the equation

3 where Q = capacity of the u n i t , cm /sec w = impel 1 e r speed, rev01 utions/sec r = radius of impeller, cm L = length of impeller suction tube, cm

Ap = difference i n density of l i gh t and heavy phases, g/cm 3 3

p = average density, g/cm A = area of i n l e t tube

2 . . g = 980 cm/sec Subscripts 1 and 2 re fer to the p i lo t unit and the scaled u n i t , respectively. ,

Finally, blades a re attached to the impeller i n order to give similar . . visual mixing as was observed in the p i lo t u n i t . ( I t has been found that

geometrically similar blades a re a good f i r s t t r y . )

3.3 THE EFFECT OF ENTRAINMENT

Entrainment i n a mixer-settl e r contactor was modeled. by Schl eicher (100)

usi ng the fo l l owi ng assumptions.

The amount of entrainment in a given phase i s the same from each

s e t t l e r . The solvent and solute-free ra f f ina te are immiscible (or the i r solu-

bil i t y does not vary w i t h solute concentration and hence stage number). The volume ra tes of solvent and feed phases do not change from stage

to stage. The dis t r ibut ion coefficient (equilibrium r a t i o ) i s constant; tha t i s

i t i s not a function of concentration. Coalescence and redispersion of the dispersed phase and mixing of the continuous phase in the mixer i s so rapid tha t the solute concentra- t ion i s uniform throughout each phase. The ra te of mass transfer in the mixer i s given by Kav (xn - myn).

Kav i s assumed to be the same for every mixer. All mass t ransfer takes place i n the mixer.

Throughout most of the studied range of parameters the s e t t l e r e f f i - ciency i s correlated within 5% by the following empirical equation:

E e = log F + (N - 1 ) log A '

N log F

where

For F = 1 t h i s simplifies to

Here,Em i s the efficiency of a single mixer, Ft / ( l + F t ) . I t i s easi ly shown tha t t h i s expression for the mixer efficiency i s equivalent to the

Murphree plate efficiency of a d i s t i l l a t i o n column equation (page 3-10) i s exact for the case of t = -.

For the overall efficiency i t was found tha t multiplying the s e t t l e r efficiency by an overall mixer efficiency gives an adequate correlation.

The overall efficiency of an extractor w i t h no entrainment i s equal to the mixer efficiency only when the extraction factor i s unity. In general

This equation mu1 t i pl ied by the s e t t l e r efficiency correlates the overall efficiency within 10% throughout most of the range of parameters investigated; tha t i s

- Eo - E,E, .

The l a s t three equations afford a means of calculating the number of actual stages of a mixer-settler extractor from the entrainment and mass t ransfer ra tes ,

where E, = entrainment or s e t t l e r efficiency, N o / N

Em = Murphree efficiency i n d i s t i l l a t i o n or mixer efficiency in extraction, F t / ( l + F t )

Emo = overall efficiency of a column w i t h no entrainment

Eo = overall efficiency, N 1 / N

F = extraction factor , mQt/Qs

f = fraction of Qt entrained i n the solvent phase from a s e t t l e r Kav = product of a mass t ransfer coefficient and the interfacial

area per mixer

N = number of actual stages No = number of stages to e f fec t a given extraction w i t h no

entrainment . . N1 = number of theoretical stages Qt = flow ra te of feed phase to extractor

. . Qs = flow ra t e of solvent phase t o extractor s = fraction of QS entrained i n the feed phase from a s e t t l e r

t = Kav/Qs

Representative resul ts obtained from using th i s calculational method to determine the effects of some of the individual variables on s e t t l e r efficiency are l i s t ed in Table 34. This analysis can be applied to the design of s e t t l e r s , since i t suggests that s e t t l e r s , other than a f t e r s e t t l e r s , are sometimes overdesigned. If there are no complicating con- sequences of entrainment, such as the formation of s table emulsions, entrainment rates as high as 10% are rarely consequential. The resu l t s will also be useful fo r interpreting experimental data. In particular i f an extractor has low efficiency, measurements of entrainment from the s e t t l e r s will es tabl ish whether the low flow efficiency i s caused by the entrainment or by poor mass transfer i n the mixers.

TABLE 34. Results of Calculational Method

The major conclusion to be drawn from t h i s work i s tha t high entrainment rates have relat ively l i t t l e e f fec t on the efficiency of mixer-settler extractors. When such extractors have poor efficiency, i t i s therefore more l ike ly t o be caused by a low mass t ransfer r a t e than by entrainment from the s e t t l e r s . This suggests that efficiency of some mixer s e t t l e r s might be improved by operating the mixers a t higher ra tes provided that : 1 ) no deleterious effects occur such as the formation of s table emulsions, and 2 ) the capacity of the a f t e r s e t t l e r s i s adequate. If a f t e r s e t t l e r s a re not used, then improvement might be obtained without excessive entrainment in the effluents by increasing the mixing rates i n a l l b u t the f i r s t and l a s t mixers.

SOLVENT EXTRACTION ECONOMICS

The economic factors to be considered in solvent extraction and other

factors are considered by Treybal. ( ' l 6 ) The total annual cost of extracting a solute from a feed solution may be considered to be the sum of s ix cost quant i t ies , as outlined i n Table 35. I f a flow ra te of feed solution, the concentration of contained solute , and the ident i ty of the solvent to be used are s t ipulated, the quantit ies which may be s e t to produce an optimum arrangement are those l i s t ed i n the lower part of Table 35, together w i t h the cost items which each influences. Treybal also presents equations f o r determining extractor cost , cost of solute in the raff inate , cost of recovered solvent, and cost of l o s t solvent. A method for calcu- la t ing an economic scale-up index i s a lso described as well as a short-cut method to f i n d the most economic value of volumetric flow ra te .

3.5 DESIGN CONSIDERATIONS FOR MIXER-SETTLERS EXTRACTORS

3.5.1 Mixer-Settl e r Design Parameters

A state-of-the-art comparison, as i t was known in 1951, of mixer- s e t t l e r extraction types i s presented by Davis. (38339) A discussion of

s t i r r ing motors and shaft sea ls , ag i ta tor flow and design, and accessory . . equipment i s a lso included. Within the mixer-settler type of extraction

equipment many variations in design are possible. One of the major factors

TABLE 35. To ta l Annual Cost o f E x t r a c t i n g a So lu te from a Feed S o l u t i o n

EXTRACTION COSTS

C t = annual total cost of extraction process

I = annual cost of multistage extractor

I1 = annual value of unextracted solute

I11 = annual cost of solvent recovery from the extract IV = annual cost of solvent recovery from the raff inate

V = annual cost of los t solvent VI = annual labor cost

QUANTITIES TO BE OPTIMIZED

Quantity Cost Term Affected

Design of extractor stages I Concentration of solute i n raff inate I , 11, I11

Concentration of solute in recycled solvent I , I11

Solvent-to-feed ra t io I , 111, V

Concentration of solvent l e f t in product 111, V

Concentration of solvent in stripped raff inate IV, V

Reflux r a t i o for solvent recovery fran extract by d i s i 1 la- t ion, or similar item i f another operation i s used I I I Reflux ra t io fo r solvent recovery from raff inate by d i s t i l l a t i on I V

MAJOR ASSUMPTIONS

1 . Insolubil i ty of solvent and feed. 2. One solute extracted in a countercurrent multistage extractor. 3 . Mixer s e t t l e r scale-up factors,

Geometrically similar, baffled mixers, height - diameter. Agitation with flat-blade turbine impel lers .

Equal agi ta tor power to liquids per unit volume flow rate of liquids.

4. Constant Murphree stage efficiency of a l l stages i n any one multistage cascade. Relative vo la t i l i ty of solvent and extracted solute

Annular labor costs Loss of solvent i n d i s t i 1 led product and stripped raffinate negligible.

Solvent loss proportional to number of extraction stages and solvent circu- lation rate.

i s i n the design of a common shaft for a l l s t i r r e r s , versus an individual shaft fo r each stage. Davis found tha t the use of a common shaft evidently requires. a more d i rec t interconnection between the stages ; however, t h i s type appears less expensive both to construct and to maintain.

Another major factor i s the vertical versus horizontal arrangement of the stages. In general, the vertical units possess a comnon shaft and the horizontal units do n o t . Also, the t ransfer between stages almost always occurs by gravity in the vertical type, while i t may occur e i ther by gravity or by pumping one or both streams in a horizontal u n i t .

A t h i r d major design factor i s the cocurrent versus countercurrent se t t l i ng w i t h i n each stage. In cocurrent se t t l i ng , the emulsion produced in the mixing chamber passes to a single se t t l i ng chamber, from which the separated phases move to the adjacent stages. In countercurrent se t t l i ng , the emulsion spreads into two se t t l i ng chambers, one above and one below the mixing chamber. From the upper s e t t l e r , the 1 ight phase i s carried to the next higher stage, while the heavy phase i s returned to the mixing chamber; from the lower s e t t l e r , the heavy phase i s withdrawn and the l igh t phase i s returned to the mixer.

The final major factor i s the control of the r a t io of phases i n the mixing chamber, independently of the flow ra t e s , which i s permitted by some

designs. This will allow the residence time to be increased for the phase i n which the slow transfer step occurs. This phase control can take place only i f the pressure dis t r ibut ion i n the mixing chamber i s uniform enough to permit the density of f lu ids to cause an equalization of densit ies between mixing and se t t l i ng chamber; then the control of the heavy phase level i n the se t t l i ng chamber will control i t s volume i n the mixing section. I f the emulsion entering the se t t l i ng chamber i s uniform w i t h that i n the mixing chamber, then back flow of one phase must occur from the se t t l i ng chamber to the mixing chamber, t o permit the phase r a t i o to be independent of flow ra te . Therefore, i f the organic-to-aqueous phase-ratio i s greater

than the organic-to-aqueous flow ra t io , a certain amount of countercurrent se t t l ing o r recycling of the organic phase must be postulated, even though

the overall flow to each se t t l i ng chamber i s cocurrent. Twelve industrial

designs fo r mixer-settlers a re compared in Table 36.

TABLE 36. Comparison o f Twelve I n d u s t r i a l Mi x e r - S e t t l e r Designs

R e l a t i o n o f Phase R a t i o ( i n M ix ing

Type o f D r i v i n g Force Chamber) t o Ove ra l l I n ven to r Type o f S t i r r i n g S e t t l i n g Arrangement f o r Flow Flow R a t i o

McKi t t r i c k Common s h a f t Cocurren t V e r t i c a l G r a v i t y Independent

Schoeneborn Comnon s h a f t Cocurrent V e r t i c a l G r a v i t y Dependent

McConnell Comnon s h a f t Cocurren t V e r t i c a l Heavy phase i s Independent pumped, 1 i g h t phase by g r a v i t y

Schei be1 Comnon s h a f t Countercurrent V e r t i c a l G r a v i t y Dependent

B o t t a r o Comnon sha f t Countercurrent Nea r - ve r t i ca l G r a v i t y Dependent

Othmer Common sha f t Countercurrent V e r t i c a l G r a v i t y Independent W I -1

Van D i j c k Common sha f t Countercurrent Near-hor izonta l m o r i n d i v i d u a l

s t i r r e r s

Hol 1 ey I n d i v i d u a l s t i r r e r s Countercurrent Near-hor izonta l

Mensing I n d i v i d u a l s t i r r e r s Countercurrent Ho r i zon ta l

Ed1 eanu I n d i v i d u a l s t i r r e r s Cocurrent Ho r i zon ta l

Standard Oi 1 I n d i v i d u a l s t i r r e r s Cocurrent Near-hor izon t a l Devel opment

G r a v i t y E i t h e r dependent o r independent

G r a v i t y Independent

Both phases pumped Independent by m ixer

L i g h t phase i s Dependent pumped, heavy phase by g r a v i t y

G r a v i t y Independent

Gordon I n d i v i d u a l s t i r r e r s Cocurrent Hor i zon ta l Both phases pumped Dependent by m i xe r

3 . 5 . 2 Review of Mixer-Settler Design

A review has been made of mixer design, s e t t l e r design, mixer-settler

scale-up, and a comparison of pump mix and gravity flow mixer s e t t l e r s by Roys ten. (91 ) These a re sumnarized in the fol lowing subsections.

Mixer Desi gn

The design of a mixer follows the principles used for a continuously- s t i r r ed tank reactor. Usually, for a given mixer design, the residence time i n the mixer determines the efficiency of mixing and, fo r a given efficiency and throughput, the volume of the mixing chamber i s obtained. The chamber may be cyl indrical (requiring baff les) or rectangular (usual ly

unbaffled) with a f l a t turbine or similar impeller. The mixer dimensions usually follow those generally accepted for batch mixers.

Secondary haze i s a very f ine suspension of one phase in the other. I t resu l t s i n poor s e t t l e r performance and high solvent losses,and may be created by unsatisfactory impel 1 e r design. Shrouded impel 1 ers with 1 ow shear character is t ics operated a t low speeds minimize t h i s problem.

The sca t t e r of residence times of the droplets in the mixer lowers the extraction efficiency. This may be improved by introducing both incoming phases into the eye of the impeller. In systems in which there i s the r isk of a change of the continuous phase or i n which one phase has a much lower flow ra t e than the other , mixing efficiency and s t a b i l i t y of the mixer-settler may be improved by recycling material of the relevant phase from the s e t t l e r to the mixer.

Se t t l e r Design

The s e t t l e r may be a simple cylinder or rectangular box. The s ize and shape of the unit a re determined by the depth of the emulsion band, and by the depth of liquid above and below the band required to minimize the carryover of entrained liquid. In the processing of nuclear materials, c r i t i - ca l i ty considerations may also a f fec t the shape of the s e t t l e r and the mixer.

The r a t e of coalescence of the emulsion af fec ts the depth of the emulsion band and determines to a large extent the residence time in the s e t t l e r

and, for a given flow ra te , the plan area of the s e t t l e r interface. The ra te of coalescence may be increased by heating the emulsion or adjusting

i t s acidi ty or by placing baffles in the s e t t l e r . Electric f i e lds may also !

be used t o promote coalescence. I t has been shown tha t i n the extraction of uranium the ra te of coalescence doubled with a temperature increase from 10 to 25OC.

The presence of "picket-fence" baffles i n the s e t t l e r has been found to enhance coalescence. Similar schemes used mesh although th i s approach may increase the r i sk of blockages by crud. Baffles which are wetted by the dispersed phase promote coalescence. Flow ra te and concentration variations and sol ids accumulations also a f fec t the depth of the emulsion. By contrast , i t was found tha t when using a uranium-tributyl phosphate- . _

n i t r i c acid system, baffles and also different diluents had l i t t l e e f fec t on improving the ra tes of coalescence.

Having established a sui table depth and plan area of the emulsion band, the length/width r a t io i n rectangular s e t t l e r s must be considered. The l inear velocity of the phases down the s e t t l e r i s a major design cr i te r ion . The l inear velocity of the l ight phase determined the c res t height of th i s phase over the ou t l e t weir and, consequently, the pressure head loss of th i s phase. In addition, the l inear velocity of th i s phase determined the ra te of re-entrainment of the heavy phase from the emulsion band. The length/width ra t io of the s e t t l e r should decrease w i t h increase in through- p u t i f the depth of solution remained constant. I t has been postulated that for cocurrent se t t l i ng proposed that the l inear axial velocity of the phases in the s e t t l e r should not exceed 10 mn s-' t o avoid the carryover of secondary haze.

The r e l i a b i l i t y of the s e t t l e r i s affected by the accumulation of crud a t the interface. This may be minimized by using feed materials; however, devices have been used which clean the interface mechanically. A sweeping arm or a moving mesh screen or pumping off the interface or chemical t r ea t - ment of the solvents to reduce accumulation of crud have been proposed.

Despite the problems associated w i t h crud, a mixer-settler can operate with solids which are maintained i n suspension and do not accumulate a t the

..I . interface.

Mixer-Settl e r Scal e-Up

I t has been found tha t in some instances mixers may be scaled-up by geometric similitude a t constant power per u n i t volume and s e t t l e r s on the

basis of constant flow ra t e per u n i t horizontal cross-sectional area; t h i s approach has wide support. For geometrically similar mixers a more s a t i s - factory basis of scale-up i s by equal torque per u n i t volume. This approach resu l t s in similar velocity r a t io dis t r ibut ion in both prototype and production mixers. This i s advantageous i n shear sensit ive mixing where, fo r example, secondary haze generation may be important. The dis t r ibut ion of f lu id shear was examined and constant power per u n i t volume was suggested as the basis for scale-up. For shear sensi t ive mixing, the maximum shear can be reduced by changing the geometry of the system during scale-up. Using th i s technique, the impel l e r diameter-to-tank r a t io and the impel l e r diameter-to-width r a t i o are increased,and the speed of rotation of the

impeller i s decreased as the tank i s scaled up . This method preserves

constant impeller t i p speed and thus maximum shear ra te .

Comparison of the Pump-Mix and Gravity-Flow Mixer-Settlers

The maximum throughput of the pump-mix units was lower than that of

the similarly sized gravity-flow units fo r the kerosene: water system. This difference was mainly due to the smaller ports and more tortuous flow paths i n the pump-mix units giving a relat ively larger res t r ic t ion to flow. Note that a small 5% increase in the s ize of the ports in the pump-mix u n i t increased the maximum throughput by 20%. The interface levels in the pump-mix unit increased rapidly w i t h the increase in flow ra te , whereas the gravity-flow unit maintained fixed levels approximately independent of flow rate . The character is t ics of the gravity-flow unit r e f l ec t the use

of large open ports with no other res t r ic t ions to flow.

With pump-mix mixer-settlers, the impeller has to be designed to give a certain pumping rate . If the flow i s below that r a t e , the aqueous phase

i s pumped too strongly resulting in low interface levels in the se t t lers which can lead to back-mixing from stage to stage. A t flow rates above the design rate, the pumping capacity of the impellers i s corroded and the impeller offers a restriction to the flow of the aqueous phase causing the interface to r i se rapidly. Thus, there i s a limited range of flow rates for satisfactory performance and this range i s a function of the design of the impeller. This analysis assumes that the impeller pumps only the aqueous phase and that the organic phase i s continuous and able to bypass the impel 1 er.

Conclusions

The pump-mix mixer-settler concept gives independent control of each se t t l e r interface and reduces the nee'd for interstage pumps in large units.

However, these units are usually designed t o operate over a limited range of flow rates.

The gravity flow design allows each stage t o be hydraulically independent, the mixer can be designed t o give the minimum generation of secondary haze, a bank of units can continue t o operate with one or more mixers defective, the design can deal with large ranges of flow rates, and the overall construction of a unit i s relatively simple.

The throughput of pump-mix mixer-settlers can be improved by:

enlarging the area of the ports used t o admit aqueous material from

the antechamber into the mixing chamber, enlarging the mixed phase port into a full width baffled s lo t , and increasing the size of the organic and aqueous outlet ports in the

se t t l e r .

3.5.3 Additional Mixer-Settler Types

Many other mixer-settler types have been devised and tested. Several of these studies are summarized in the following subsections.

The Effect of Design Parameters on Mixer-Settler Efficiency

Using a four-stage mixer-settler unit a t mixer speeds between 1200 and

2500 rpm and throughputs between 10 and 150 ml/min, Bloom 5, discusses

baffling, pumping, paddle arrangement, and their effect on efficiency. I t

was concluded that a 75% stage efficiency i s possible.

Connecti on of Mi xing-Settl i ng Chambers

A mixer-settler having a unique interconnection of mixing and settling

chambers by means of weir tubes i s described by Whately. (lZ8) NO operating

data are given.

Mixer-Settler Bank for Thorium Purification

The use of three ten-stage mixer-settler units in series t o simulate

extraction-scrub-stri p cycles for thorium purification with 30% TBP in

di 1 uent was described by Burkhardt. (23) Each stage had a mixing section

3 1 / 2 in. wide, 4 in. long and 6 in. deep. The settling section was

3 1 /2 in. wide, 16 in. long, and 6 in. deep. A t an aqueous feed concen-

tration of 450 g thorium/a, impeller speeds from 350 to 450 rpm, and

organic-to-aqueous phase ratios of 7.5 t o 1 for extraction, 23 to 1 for

scrubbing, and 1.75 to 1 for stripping, as well as the stage efficiencies

listed in Table 37.

TABLE 37. Stage Efficiencies

Operation Stage Efficiency, %

Extraction 80

Scrubbing 80 near feed point to 20 a t product end

Stripping 50 to 60

Design Considerations

The fol 1 owing

Baille: (5)

des i gn recommendations for mixer-settler units are made

mixed phase port height - 114 to 112 in. above interface, mixed phase baffle - 1 112 i n . wide and.not less than 1 in. high, mode of heavy phase - entry to mixing compartment - f a l se bottom

with a 314-in. diameter hole, effect of paddle type impeller - best mixing w i t h tube

112-in. above mixer base and impeller 118-in. above tube.

effect of flow ra te on impeller type - not clear.

effect of blades - for blades 114-in. wide by 112-in. high on a

114-in. diameter shaft , the optimum speed i s 400 rpm. If the blade

width i s increased to 318-in. the best speed i s 290 rpm.

I t was concluded that a 10 stage bank of 27 x 9 x 3.5 i n . unit would

be suitable i f the depth in the s e t t l e r i s maintained a t 3 in .

Mixer-Settl er Operating Variables

A 10-stage c r i t i c a l l y safe mixer-settler was tested by ~ a i l l e ' ~ ) who

found the effects of operating variables to be:

Flow-rate - an increase i n the aqueous flow ra te from 25 to 85 mllrnin

caused a r i s e in interface height of less than 0.4 i n . for each stage. Impeller speed - speeds between 250 and 350 rpm had no effect on

interface level. A t speeds above 350 rpm there was a spillover of

phases, and a t speeds below 250 rpm mixing was poor. Impeller heights - i f the height of the impeller i s decreased 314 to

518 in. above the base, the interface in the preceding stage f e l l

0.4 i n . b u t the capacity of the unit was increased. A further decrease

to 112-in. above the base produced pumping so ef f ic ient that an inter-

face could not be maintained. A flow ra te of three times normal was

required to prevent the interface from fa l l ing out of the operating

range.

With a feed containing 3.7 g uraniumla and 44.5 g aluminurnla to the

5th stage and 1M - ANN to the f i r s t stage, a stage efficiency of 80% was

obtained. When a n i t ra te deficient flowsheet was used, stage efficiency

increased to 95%.

One-Stage Mixer E f f i c i ency

Ryo n (94) d e s c r i b e s t h e t e s t i n g o f a 6-in. diameter mixer i n a ba r r e l

t o determine t h e e f f e c t i v e n e s s of t h e e x t r a c t i o n of uranium from a 1 g / ~ s o l u t i o n by a 0.1M - s o l u t i o n of a long cha in amine. Grea te r than 90% s t a g e

e f f i c i e n c y was ob ta ined wi th a power i n p u t of 6 Hp/1000 gal and a r e s idence

time of up t o 1 .5 min. The u n i t showed g r e a t e r than 90% s t a g e e f f i c i e n c y

when c h l o r i d e , n i t r a t e , o r carbonate was t h e s t r i p p i n g agen t a t 50 Hp/

1000 gal power i n p u t and a r e s i d e n c e time of 0.25 min.

Minia ture Mixer -Se t t le r f o r Purex and Thorex Flowsheets

A number o f r a d i o a c t i v e runs made i n a m i n i a t u r e m i x e r - s e t t l e r u n i t

using both t h e Purex and Thorex f lowshee t a r e desc r ibed by Kl i tguard . (71 )

The u n i t c o n s i s t e d of e i g h t e x t r a c t i o n s t a g e s , e i g h t s c rub s t a g e s , f i v e

p a r t i t i o n i n g s t a g e s , e i g h t back e x t r a c t i o n s t a g e s , and 16 s t r i p p i n g s t a g e s .

The Purex runs showed a uranium l o s s of 0.007%. S tage e f f i c i e n c i e s o f 65%

f o r e x t r a c t i o n and 77% f o r s t r i p p i n g were obta ined . The waste l o s s e s i n

t h e Thorex runs were 0.19% f o r uranium and 0.073% f o r thorium. Decontamina-

t i o n f a c t o r s f o r thorium from uranium and uranium from thorium were 360 and

550, r e s p e c t i v e l y .

The l i m i t i n g f low of t h e u n i t was found t o be 3 a /hr f o r the Purex

runs and 2 a l h r f o r t h e Thorex runs. This i s equ iva l en t t o 85 g of uranium

o r 30 g o f thor iumlhr .

Mixer -Se t t le r S tage E f f i c i ency a s a Function of Impel ler C h a r a c t e r i s t i c s

A convent ional m i x e r - s e t t l e r u n i t was t e s t e d t o determine i t s e f f e c t i v e -

ness i n recover ing copper from a 0.05 t o 0.1 g copper/R s o l u t i o n by ex t r ac - t i o n with 5 t o 11% ion exchange r e s i n d i s so lved i n kerosene; the r e s u l t s

a r e repor ted by warwick. ( l An impel l e r o f double-shrouded backward-

swept vane des ign was l oca t ed i n t h e c e n t e r of t h e mixing compartment. 3 2 A c o r r e l a t i o n o f N D where N i s t h e impe l l e r speed i n r e v o l u t i o n s per

second and D i s t h e impe l l e r d iameter i n f e e t showed t h a t s t a g e e f f i c i e n c i e s 3 2 approached 95% a t N D values above 80. The d a t a a l s o showed t h a t t h e d i s -

pers ion band width increased i n an asymptot ical manner above a mixed phase

2 flow r a t e of 2.0 g a l l h r l f t . Stripping e f f i c ienc ies of 95% were obtained

w i t h a s t r i p se lec t ion containing 30 g copper plus 170 g s u l f u r i c ac id la .

Performance of a One-Stage Mixer-Settler . A small , glass air-pul sed mixer-set t l e r has countercurrent flow

between stages and cocurrent flow w i t h i n a s tage. As discussed by

Srinivarsen ( l o4 ) mixing energy, provided by a regulated a i r and vacuum

supply, i s applied t o a mixing chamber i n a pulsing manner. The frequency

of the pulsat ions t es ted w i t h 80 and 110 cycles/sec, and the pulse amp1 i -

tude ranged between 7 and 12 i n . When t e s t s were ca r r i ed out w i t h 30% TBP

i n kerosene a s the organic phase and 50 g uraniumla i n 3M - n i t r i c ac id , the

u n i t demonstrated a s tage e f f i c iency of 90 t o 100%.

Effect of Operating Conditions on Mixer-Settl e r Efficiency

Single and mult istage experiments ca r r i ed out using mixer-se t t lers

having 10 x 10 x 10 cm mixer boxes,and s e t t l e r dimensions of 8 cm wide,

20 cm deep and 12.5 cm long a r e described by Rowden. The pump-mix

impeller used i n the experiments was a t a t i p speed of 2.61 Mlsec.

The s ingle-s tage experiments were ca r r i ed out using an aqueous phase

containing 0.1 g copperla plus 3.5 g su l fu r i c a c id l a , and on organic phase

containing 18 vol% LIX 64 N (an ion exchange r e s in ) i n Napoleum. W i t h

organic-to-aqueous phase r a t i o s between 311 and 114, a s tage eff ic iency of

85 t o 95% was obtained f o r ext ract ion. Str ipping t he organic a t an O / A

r a t i o of 3 showed s tage e f f i c i enc i e s between 85 and 100%.

The system used i n t he mult istage experiments was aqueous, 45 g

copperla plus 0.5 g su l fu r i c ac idla-40~01% LIX 73 i n Napoleum. Organic-

to-aqueous flow r a t i o s were 11.25 f o r ext ract ion and 3.0 f o r s t r ipp ing .

Under these condi t ions , ext ract ion and s t r ipp ing e f f i c i enc i e s were 75 t o

85, and 85 t o 95%, respect ively .

Under organic continuous mixer condit ions, the re i s an increase i n

e f f i c iency on decreasing the organic/aqueous r a t i o from 1:1 t o 1:4. Under

aqueous continuous mixer condit ions, the l a rge s t increase i n e f f ic iency i s shown when t he proportion of organic dispersed is increased by increasing

t he operating organic/aqueous r a t i o from 1 :1 t o 3:1.

Entrainment. Under organic continuous mixer conditions, the values of organic entrainment i n the aqueous phase appear t o be v i r tua l ly independent of the operating organic-to-aqueous (0 :A) r a t io . However, under aqueous phase continuous operation organic entrainment i n the aqueous phase i s constant from an 0:A value of 4:1 to an 0:A value of 1 : I , b u t then increases sharply.

By contrast , aqueous entrainment in the organic phase under organic phase continuous operation i s very high a t an 0:A r a t i o of 4:1, but drops to a negligible value when an 0:A r a t i o of 1 :I i s reached. Under aqueous phase continuous conditions, aqueous entrainment i n the organic phase i s essent ial ly constant.

The ef fec t of changes i n the operating organic-to-aqueous r a t io on

the performance of laboratory-scale mixer-settler systems have been s igni f i - cant. A t commercial plant-scale, disregard of the e f fec t of th i s parameter could lead to serious operational problems. Thus, the operating organic- to-aqueous r a t io i s t o be considered as a major design parameter.

4.0 CENTRIFUGAL CONTACTORS

4.0 CENTRIFUGAL CONTACTORS

The centrifugal extractor i s a horizontal countercurrent liquid-

liquid contacting device consisting of a series of concentric stages in

which bo th mixing and settling are accelerated by a variable centrifugal

force f ield.

4.1 SAVANNAH RIVER DEVELOPMENT

4.1 .1 Centrifugal Contactor Performance

The performance characteristics of a 5-in. centrifugal extractor are

described by Webster. ( lZ6) For the 1.2M - Al(N03)3 - 6% TBP system in ultrasene Webster f i r s t found that:

the volume of entrained a i r in the liquid increases with liquid dis-

charge rate up t o values of 40% a i r . The a i r has l i t t l e effect on

efficiency, b u t must be considered in sizing the units. between 600 and 1800 rpm the capacity of the unit varies with the

0.8 power of the rotor speed. the re1 a t i onshi p between rotor speed, capacity and aqueous-to-organic

flow rat io ( l is ted in Table 38) .

TABLE 38. Re1 a t i onshi p Between Rotor Speed, Capacity and Aqueous-to-Organic Flow Ratio

Rotor Speed, Capacity , Aqueous-to- rpm gpm Organic Ratio

1800 6.5 1.5

When the 0.5M - ni t r i c acid:6% TBP system in ultrasene was used, flow

rates were 15 t o 30% higher when other variables were held constant. I t

was also shown that interface solids had no effect upon capacity.

4.1.2 Centrifugal Contactor Performance - 16 Stage Unit

A 16-stage centrifugal contactor i s described by Schlea. (95) The unit had access points fo r introducing solutions to any stage, f o r removing samples, and for inserting in-line instrumentation into flowing streams into flowing streams w i t h i n the contactor. Themcoupl e we1 1 s and internal ducts fo r circulating heating or cooling water were available also.

Operating Characteristics

The major operating character is t ics a re residence time, mixing inten-

s i t y , and centrifugal force in the s e t t l e r . The residence time varies with throughput and organic-to-aqueous flow ra t io , since the dynamic holdup of each phase i s fixed by the position of the overflow weirs. Mixing intensi ty varies w i t h the agi ta tor speed, throughput, and flow ra t io . Uranium extraction efficiency, which i s controlled by diffusion and mixing intensi ty , was used as the indicator of mixing intensi ty .

Results

The f i r s t solvent extraction cycle of the Purex process was s a t i s - factor i ly adapted to short-residence contactors. Process performance w i t h

an organic phase residence time of four seconds per stage was equivalent to performance normally obtained w i t h conventional mixer-settlers. With normal levels of saturation i n the 1A bank, purification of uranium and

4 plutonium was excel1 ent (gamma decontamination factor greater than 10 ) , and cross-contamination of uranium and plutonium was negliglble. The t e s t s included a demonstration of sat isfactory performance w i t h solvent tha t had been exposed t o typical levels of radiation for about 300 hr.

Two necessary process modifications were:

elevation of temperatures i n the 1A bank to emphasize plutonium decontamination. destruction of excess nitrous acid in the feed solution (1AF) t o

preserve the 1 B bank fo r parti t ioning.

The following characteristics of the process were also observed:

zirconium-niobium decontamination increased almost 1 inearly w i t h

increases in the irradiation level of the fuel, indicating the possible presence of a "carrier" t h a t retained a fixed amount of activity through the process.

a excessive dibutyl phosphate did n o t form a t elevated temperatures, a maximum solvent saturation a t the feed stage of the 1 A bank gave

the highest decontamination, and decontamination with solvent that had been exposed 300 hr to radio-

ly t ic degradation in conventional mixer-settlers was satisfactory.

Factors Affectina Decontamination of the Products

Irradiation Level. Decontamination from zirconium-niobium increased almost linearly, as the irradiation level of the uranium increased; decontamination from ruthenium was independent of the irradiation level. The linear variation of zirconium-niobium decontamination suggests the presence of an organophilic ligand that carries a fixed quantity of zirconium- niobium through the process.

Temperature. The marked effect of elevated temperatures on ruthenium

decontamination i s consistent with previous studies using miniature mixer- set t lers . Removal of zirconium-niobium was also sl ightly better a t elevated temperatures, confirming that DBP does n o t form t o a harmful extent when residence times are short.

Improved ruthenium decontamination a t elevated temperatures i s a t t r i - buted to a lower ruthenium distribution coefficient in the scrub section of the 1 A bank. All increased ruthenium decontamination a t the higher temperatures occurs in the scrub section.

Solvent Saturation. Decontamination with two to three saturated stages was as good as that with more than three saturated stages, b u t

decontamination was poor when only the feed stage was saturated. In most

runs, two t o three saturated stages (containing a relatively high concentration of uranium) were maintained in the extraction section of the 1A bank.

Solvent Q u a l i t y . Decontamination was s a t i s f a c t o r y w i t h s o l v e n t t h a t

had been exposed about 300 h r t o a c i d and r a d i a t i o n f i e l d s t y p i c a l of t he

1A bank and an a d d i t i o n a l 600 h r t o a c i d alone. I .

4.1.3 C e n t r i f u g a l Contactor Performance - Five-Stage U n i t

K i s hbaugh (70) descr ibed the capac i t y and mass t r a n s f e r ob ta ined i n a

f i ve-s tage bank of 10- in. diameter c e n t r i f u g a l con tac to rs having a r o t o r

speed of 1745 rpm. Using t h e system 0.5 - M n i t r i c acid-30.5 v o l % TBP i n

u l t rasene, i t was shown t h a t a t a throughput o f 70 gpm entra inment was

e s s e n t i a l l y constant a t 2% between an A/O o f 0.2 t o 2 and then increases.

S i m i l a r l y , a t a throughput o f 60 gpm entra inment was i n t h e range o f 0.05%

between an A/O o f 0.1 t o 2 and then increased.

The con tac to r was a l s o tes ted f o r e x t r a c t i o n and s t r i p p i n g e f f i c i ency

w i t h t h e systems 177 g uranium/a, 2.5 M n i t r i c a c i d aqueous - 30.5 vo l%

TBP i n u l t r asene organ ic and 0.05 - M n i t r i c a c i d aqueous - 60 g uraniumla

organic , r espec t i ve l y . Under e x t r a c t i o n cond i t i ons the uranium loss was

0.0008%, and under s t r i p p i n g cond i t i ons 89 t o 94% stage e f f i c i e n c y was

obta ined.

Kishbaugh a l s o determined t h a t t h e a d d i t i o n o f 5000 ppm manganese

d i o x i d e t o t h e feed showed no de tec tab le e f f e c t on t h e ope ra t i ng charac-

t e r i s t i c s o f t h e u n i t and t h a t a a throughput of 50 gpm the power r e q u i r e -

ment was 10 kW.

4.1.4 C e n t r i f u g a l Contactor Capacity Tests

Capacity t e s t s descr ibed by Good1 e t t (54) were made w i t h s imu la ted

2 4 4 ~ m process cond i t i ons f o r batch e x t r a c t i o n , s t r i p p i n g , and so l ven t wash-

ing . I n each t e s t , t h e two l i q u i d phases were mixed f o r 30 min i n the feed

tank w i t h a g i t a t i o n s i m i l a r t o t h e maximum i n t he p l a n t . The a g i t a t i o n was

then stopped, and the mixed-phase feed (Table 39) was j e t t e d immediately t o

t he c e n t r i f u g a l separator .

The mixed s o l u t i o n s i n t he feed tank were mainta ined between the

expected maximum and minimum p l a n t temperature (45 and 25"CO. With

TABLE 39. Cen t r i f uga l Contactor Feeds 244~m Separat ion

Phase Volume Organic Rat io,

Aqueous Phase Phase 'A10

Ext ract ion 1.36 sp g r A1 (N03)3 50% TBP i n 1 0 .5y HMO3 "Ul trasene"

St r ipp ing 0.2M HN03 I1 112

Washi ng 2.5% Na2C03 II 114 0.8% NaOH

t o t a l f lows o f 40 t o 50 gpm f o r t he four so lu t i ons , t he feed temperature

had on l y a small e f f e c t on feed f low. Feed t e s t s w i t h a pump showed t h a t

t he capac i ty of the c e n t r i f u g e e x i t l i n e t o the waste tank i s about 60 gpm.

The capac i ty o f t he e x i t l i n e t o the product tank i s more than 65 gpm.

D e l i v e r y o f t he separated organic l i q u i d t o the c o l l e c t i o n tank was

equa l l y s a t i s f a c t o r y through e i t h e r the open l i n e o r t he sealed d i p l e g

w i t h a 1/4- in . diameter vent ho le above the s o l u t i o n l e v e l .

The e x t r a c t i o n , s t r i p p i n g , and so lvent washing s o l u t i o n s were c e n t r i -

fuged as thoroughly mixed (>4.2 hp/1000 ga l ) emulsions t o determine the

l i q u i d entrainment i n each endstream a t d i f f e r e n t w e i r a i r pressures. To

main ta in <0.5% l i q u i d entrainment i n both endstreams the feed r a t e should

be <25 gpm a t 25C and <30 gpm a t 456. A c l e a r stream a t h igher r a t e s can

be obta ined by increas ing a i r pressure on the c e n t r i f u g e we i r .

4.1.5 Cen t r i f uga l Contactor Performance - 18-Stage U n i t

The performance o f an 18-stage bank o f c e n t r i f u g a l m i x e r - s e t t l e r s

has been discussed i n comprehensive rev iew-type document by Webster. (1 24)

The u n i t s were expected t o have the f o l l o w i n g advantages over pump-mix

m i x e r - s e t t l e rs :

reduced exposure of solvent to radiation

reduced aqueous and sol vent inventories

reduced space requirements easier flushing fo r process changes greater safety in handling fissionable materials accommodation to a wide variety of process solutions with varying

densi t ies and viscosi t ies .

Each stage of the centifugal mixer-settler has 5 HP, 1745 rpm rotor w i t h a ver t ica l , overhung shaft t o which i s attached to a 10-in. diameter

separating bowl and, a t the bottom, a mixing paddle-pump. Both the heavy (aqueous) and l igh t (organic) phases flow by gravity from adjacent stages and enter the pumping-mixing chamber through the tee a t the bottom. The phases a re mixed by the paddle and ejected a t the periphery of the m i x i n g

chamber into an upper chamber where the mixture moves inward along ant i - vortex vanes. The liquids a re quickly accelerated to fu l l rotational speed by eight radial vanes tha t extend the fu l l length of the bowl, and the mixed phases separate very rapidly i n the high centrifugal f i e ld (300

to 500 g ) , the heavy (aqueous) phase collecting near the wall , and the l i g h t (organic) phase near the center. The organic phase flows inward and over a c ircular weir i n the center of a baffle located a t the top of the separating section, and thrown outward through four, straight-sided, radial ducts to a col lector r i n g i n the stationary casing. A t the bowl wall, the aqueous phase i s discharged radial ly into i t s col lector r i n g . When a i r pressure i s increased, the emulsion moves inward and the surface of liquid in the jack-leg moves outward, on compensation.

The two phases flow counter-current between stages. The hold-up of each stage i s approximately 4 gallons (3 gallons in the bowl ) .

Important features previously established w i t h the five-stage prototype also apply to the 18 stage u n i t as l i s t ed below:

The hydraulic capacity of centrifugal mixer-settlers i s not adversely affected by aqueous-phase acid concentrations as low as 0.01M - HN03, i n contrast t o the behavior of pump-mix mixer-settlers. The method fo r detecting a rotor f a i lu re and the procedure for flush-

ing a u n i t containing an inoperable stage are sat isfactory. The air-weir pressures required t o control the location of the emulsion can be predicted f o r any system. The centrifugal mixer-settler performance i s not impaired by 5000 ppm

of solids (Mn02, Si02, or mercuric sulfamate) in feed solutions. Sol ids a re centrifuged out of solution and accumulate as a t h i n layer i n each stage until the ra te of deposition i s equalled by the r a t e of resuspension into the aqueous phase a t the underpass baffle; thereaf ter , the solids follow the aqueous phase through the bank.

Hydraulic and Mass Transfer Characteristics

The hydraulic and mass t ransfer character is t ics of the 18-stage bank were evaluated a t the semiworks w i t h nonradioactive solutions tha t simulated those used in the Purex extraction-scrub service. The f i r s t t e s t reproduced the low uranium conditions of the waste end of the bank: 30% tr ibutyl phosphate in "Ultrasene" contacted with 0.55 times i t s flow ra te of 1.6 M HN03

a t 60°C. The flows ranged from rates equivalent to processing 8 tons/day

of uranium to 27 tons/day. A t ra tes equivalent to 8 tons/day, sat isfactory performance (<0.5% entrainment) i s obtained throughout a span of a i r w i t h

pressure of 10 i n . of mercury; the span narrows to 4 i n . of mercury a t ra tes equivalent t o 27 tcns/day.

Tests more t ru ly simulating the Purex extraction-scrub conditions were +67 made by introducing a feed of unirradiated natural uranium (1 .lM - U ,

2.OM - HN03) a t Stage 10. The resulting change i n re la t ive phase densit ies required higher a i r pressures on the weirs for sat isfactory performance than did the solution without uranium. The mass t ransfer performance of the 18-stage bank was measured during the t e s t s w i t h unirradiated uranium, a t processing rates equivalent to 8 t o 16 tons/day. The cocurrent stage efficiencies fo r extraction approached 100%; l e s s than 0.03% of the uranium remained i n the waste stream, and less than 0.3% entrainment occurred i n

each endstream. Each mass t ransfer t e s t was followed by a Purex 1C-bank operation of the centrifugal mixer-settlers a t a r a t e equivalent to 10 tons/

day to back-extract the uranium from the organic phase; the overall mass t ransfer efficiency was approximately 95%.

The 18-stage bank of centrifugal mixer-settlers has been operating for

1 yr on radioactive feed w i t h f iss ion product gama ac t iv i ty ranging from 50 to 200 Cila. Mechanical re1 iabi l i ty has been excel l ent so f a r . The automatic control system has also performed well; the only required change was damping of the fluctuating signal from the specific gravity probe. The total shutdown time of the pump-mix, mixer-settler was 5 to 6 hr. In

contrast , the centrifugal mixer-settlers are purged by 15 to 30 min of solvent and scrub flow, and shutdown i s accomplished i n less than 1 hr.

Complete flushing of the centrifugal bank, required to obtain product purity when the equipment i s used occasionally for processes other than Purex, takes 1 or 2 hr which i s a marked improvement over the 8 to 16 hr involved i n complete flushing of the pump-mix mixer-settlers. When the

previous bank was started a f t e r a shutdown, a steady-state operation was attained i n about 16 hr; as well as can be determined, the centrifugal

bank reaches equilibrium i n about 20 m i n .

Decontami nati on by the new 18-stage bank has been roughly equivalent to tha t by the old 24-stage bank (factors of 3000 to 5000 on gama ac t iv i ty ) a t the same level of feed ac t iv i ty .

The short residence time and consequent lower exposure of solvent to radiation in the centrifugal mixer-settler has markedly reduced the retention of f iss ion products by the solvent. Although solvent from the previous operation was used w i t h the new centrifugal bank, gross gama ac t iv i ty of the solvent, both before and a f t e r washing, f e l l t o about 115 of the former values for the same feed ac t iv i t i e s . This reduction permits processing of more act ive feeds. Whereas feeds of 100 Ci/a to the pump-mix mixer-settlers caused excessive f iss ion product retention by the solvent, and dras t ica l ly reduced decontamination through the f i r s t cycle, the centrifugal bank has processed feeds of 200 C i l a w i t h no adverse affects .

The f i r s t y e a r o f exper ience wi th the c e n t r i f u g a l m i x e r - s e t t l e r s i n

r a d i o a c t i v e service has demonstrated t h e expected e a s e o f ope ra t i on and

r educ t ion of s o l v e n t damage, and has made a s t a r t on demonstrat ing mechani-

ca l r e l i a b i l i t y .

. . 4.2 ARGONNE NATIONAL LABORATORY DEVELOPMENT

4.2.1 Long Rotor Cent r i fuga l Contac tor

ern stein(") performed tests on a long r o t o r c e n t r i f u g a l c o n t a c t o r

with t h e fo l lowing dimensions:

r o t o r : 4.2 i n . i n d iameter

r o t o r s h a f t : 1.25 i n . i n d iameter

length- to-diameter r a t i o i n s e t t l i n g zone: 3.

The c a p a c i t y o f t h e u n i t could be c o r r e l a t e d by the equa t ion :

N; DEL Capaci ty a

10 Nm Dm

where N C = r o t o r speed, rpm

Nm = mixing speed, rpm

Db = r o t o r I.D., i n .

Dm = mixing paddle d iameter , i n .

L = s e t t l i n g l eng th i n r o t o r , i n .

Throughput tests were c a r r i e d o u t wi th an aqueous phase o f 0.5M - n i t r i c a c i d

and i n o rgan ic phase of e i t h e r 15 o r 30 vol% TBP i n Ul t rasene . With either o rgan ic phase t h e c a p a c i t y was 5 gprn a t 2000 rpm and 8 gpm a t 3500 rprn,

whi le a t an A/O r a t i o of 4 t h e c a p a c i t y increased t o 9 gpm a t 2000 rpm

and 17 gpm a t 3500 rpm. Entrainment was 1% o r l e s s throughout .

Manganese d iox ide was added t o t h e system dur ing one test a t a concen-

t r a t i o n o f 2500 ppm. None was found i n t h e organic phase and l i t t l e c o l -

l e c t e d i n the r o t o r .

Extraction eff ic iency was determined using 0.46M - uranium and 0.68M n i t r i c

acid i n the aqueous feed and 30 vol% TBP in ul t rasene as the organic feed. A t .

an A/O = 1 , a ro to r speed of 3000 t o 3500 rpm, and a feed r a t e of 4 t o 7 gpm

(sum of phases), a staged eff ic iency of 96 t o 100% was obtained. The mechanical performance of the u n i t was excel lent .

4.2.2 Centrifugal Contactor t o Operate i n the Annular Mixing Mode

A Savannah River model centr i fugal contactor was modified t o operate

in the annular mixing mode by:

1. removing the mixing chamber, paddle, radial ba f f l e and nozzle p l a t e ,

2. a t taching a bottom section having a baffled p la te , and

3. a t taching the organic and aqueous por ts t o s i de i n l e t .

These changes r e s u l t i n mixing occurring a s the solut ions flow downward

through the annulus between the ro to r and the casing. The modifications

and t e s t i ng a r e descri bed by Bernstei n . (13)

Capacity t e s t s using the 0.5M - n i t r i c acid:30 Vol% TBP system i n

u l t rasene were conducted a t A / O r a t i o s of 0.25 t o 4 and ro to r speeds of

2500 t o 3500. The capacity was about the same a s f o r the unmodified un i t

except t h a t the m i n i m u m capacity of 5 t o 8 gpm occurs a t a higher A / O

r a t i o , i . e . , 2 v ice 1 .

Testing w i t h Mn02 showed t h a t a l l of i t stayed i n the aqueous phase

o r i n the ro to r . Only about one-half a s much was found i n the r o to r a s had been found p r i o r t o modification.

Efficiency t e s t s w i t h a ro to r speed of 2000 t o 3500 gpm, an A / O of 1 ,

and a flow r a t e of 4 t o 7 gpm showed a s tage e f f i c iency between 97 and 100%.

The operating t e s t s of the annular centrifugal contactor have demon-

s t r a t ed t h a t i t i s a highly e f f ec t i ve u n i t with respect t o mechanical and

extract ion performance. The unique design represents a s i gn i f i c an t improve-

ment i n t h e construction of centr i fugal contactors.

I t i s apparent t h a t the annular design i s niuch more read i ly adaptable

t o remote maintenance than i s the Savannah River design. In the annular

design, a more simpler ro tary seal f o r in te r face control can be used

( s i m i l a r t o t h e one used i n t h e ANL experimental u n i t ) , and t h e motor,

s p i n d l e , and r o t o r assembly can be removed d i r e c t l y a s an i n t e g r a l u n i t .

This would permit ea sy replacement o f the only movable p a r t s o f a bank o f

c o n t a c t o r s without d i s t u r b i n g the c a s i n g assembl ies o r i n t e r s t a g e p ip ing .

The annu la r design r e t a i n s a l l o f t h e d e s i r a b l e f e a t u r e s o f t h e Savannah

River design - small holdup, s h o r t r e s idence time (and thus reduced s o l v e n t

damage a s a r e s u l t of i r r a d i a t i o n ) , r ap id a t t a inmen t of s t e a d y - s t a t e oper-

a t i n g cond i t i ons , and r ap id f l u s h o u t a t t h e end o f a processing campaign.

Additional advantages o f the annu la r design a r e der ived from t h e f a c t

t h a t t h e c e n t e r s h a f t and overhung paddle a r e e l imina t ed . As a r e s u l t ,

the r o t o r has a l i g h t e r weight and s h o r t e r o v e r a l l l e n g t h than does a r o t o r

o f the Savannah River design and e q u i v a l e n t s i z e .

4 .3 MULTISTAGE CENTRIFUGAL CONTACTORS

The Robatel c o n t a c t o r c o n s i s t s o f a series o f f i x e d , c i r c u l a r p l a t e s

t h a t a r e f i t t e d perpendicu la r t o the a x i s t o form a v e r t i c a l t r a i n o f com-

partments. Bernard ( I 1 ) t e s t e d an e i g h t - s t a g e device which had a maximum

r o t a t i o n a l speed of 5000 rpm, a bowl d iameter o f 160 mm, a l i q u i d holdup

of 950 m l , and a maximum flow r a t e of 100 a /h r . In runs with co ld uranium

t h e u n i t demonstrated about seven t h e o r e t i c a l s t a g e s f o r e x t r a c t i o n and

f i v e t o s i x s t a g e s f o r s t r i p p i n g . A t r o t o r speeds above 2500 rpm ope ra t i on

was g e n e r a l l y poor. During e x t r a c t i o n - t y p e ope ra t i on about 0.1% aqueous

entrainment was p re sen t i n t h e o rgan ic phase between r o t o r speeds o f 1500

t o 4000 rpm, and waste l o s s e s ranged between 0.1 t o 0 .5 mg uraniumla i n

t h e r a f f i n a t e when t h e f eed conta ined 90 t o 180 g uranium/a. Waste l o s s e s during the s t r i p p i n g runs were 4 t o 16 mg uranium/a.

Radioac t ive runs c a r r i e d o u t using t h e e i g h t - s t a g e bank w i t h a r o t o r

speed of 1500 rpm gave t h e fo l lowing r e s u l t s when us ing a feed con ta in ing

50 g uraniumla, and 290 mg plutoniumla:

e x t r a c t i o n waste l o s s : 0.2 mg uraniumla, 0.05 mg plutoniumla

( A / O - 1 .3 )

e x t r a c t i o n s t ages : 6 f o r uranium, 7 f o r plutonium

s t r i p p i n g waste l o s s : 1 mg uranium12 (A10 = 1 ) . o v e r a l l decontamination ( B , ~ ) - e x t r a c t i on p lus sc rub: 5000

An i n d u s t r i a l s c a l e u n i t , 5500 l b / h r t o t a l throughput which i s equiva-

l e n t t o 8 tons of uranium processed per day was a l s o t e s t e d . I t was found

t h a t e f f i c i e n c y is r e l a t i v e l y i n s e n s i t i v e t o f low r a t e but t h a t i t i s dependent on t h e uranium con ten t of t h e feed . Uranium l o s s e s ranged from

2 t o 8 mg uraniumlk from t h e e x t r a c t i o n c y c l e and 0.1 t o 1.1 mg uraniumla

from t h e s t r i p p i n g cyc le .

The a u t h o r s conclude t h a t the r e s u l t s obtained wi th c e n t r i f u g a l

e x t r a c t o r s were q u i t e s a t i s f a c t o r y and t h e i r use may be taken i n t o con-

s i d e r a t i o n i n t h e i r r a d i a t e d f u e l p rocess ing f i e l d . The t echn ica l advan-

t ages a r e s h o r t r e s idence time r e s u l t i n g i n s h o r t e r s t a r t - u p and shutdown

t imes ( t h i s f a c t enables ope ra t i on wi th weekend shutdowns) ; and small

space r equ i r ed i n a c t i v e c e l l .

4.4 MISCELLANEOUS CENTRIFUGAL CONTACTOR DEVELOPMENT

4.4.1 Cent r i fuqal Contactor Overview

The phys ica l c h a r a c t e r i s t i c s of a LuWesta c o n t a c t o r , a DeLaval con-

t r a c t o r , and a Podbi e l ni ak c o n t a c t o r a r e presented by Todd and Podbi e l - niak . ( '13) Cur ren t ly , t h e s e u n i t s vary i n s i z e from a 17- t o 60-in.

d iameter and can handle throughputs o f from 0.06 t o 600 gpm. Although a

temperature g r a d i e n t i s d i f f i c u l t t o impose, t h e u n i t s a r e extremely com-

pac t and can o p e r a t e on a very small d e n s i t y d i f f e r e n c e between the phases.

4 .4 .2 Feed and Discharge Method

Doyle (44) has patented a method whereby feed can be introduced t o and

a product d i scharged from a c e n t r i f u g a l c o n t a c t o r by the use of s leeved

tubes , t hus enhancing t h e f l exi bi 1 i t y of the c o n t a c t o r .

4.4.3 Quadronic Cent r i fuge

Doyle e t a1 . (45) d i s c u s s a ho r i zon ta l s h a f t c e n t r i f u g a l dev ice capabl e

of ope ra t i on with f eeds of 250 t o 365 gpm, flow r a t i o s (AIO) from 100/1 t o

1/100, r o t o r speeds from 500 t o 5000 rpm, and temperatures from -25' t o 350°F

He observed that: 1 ) orifices should be sized to sui t the combined through- p u t , and accomnodate both rich and lean ends without causing emulsions, and 2 ) that the radius of the unit determines the number of stages obtained while the width determines the capacity. In order for the unit to accommodate varying feed conditions, adjustments can be made to the unit to com- pensate for them (see Table 40).

TABLE 40. Adjustments for Varying Feed Compositions

Feed V a r i a b l e Operational V a r i a b l e

A S p e c i f i c g r a v i t y Rotor speed

V iscos i ty O r i f i c e adjustment

Surface tension O r i f i c e adjustment

Emuls i f iab le l i q u i d s Use o f grad ient o r i f i c e s

Capacity Change i n r o t o r speed; o r i f i c e s o r c l a r i f i c a t i o n zone

4.4.4 Pressure Balance

Some general characteristics of centrifugal contactors are described by Todd. ( '14) An equation i s developed to define the in le t pressure requirements.

2 2 'LLI = 'HLO = (0.5) ~ o - ~ ( R , , , ) N ( A G )

where PLLI = pressure of l ight liquid in

P~~~ = pressure of heavy liquid o u t RLLI = radius from shaft centerline, in.

N = rotor speed, rpm

AG = a specific gravity.

He also suggested that for optimum operation the major phase should be dispersed into the minor phase.

4.4.5 Podbi e l n iak Ex t rac tors

Purex I C System

The Podbie ln iak "Pup" u n i t was tes ted as a Pyrex I C con tac to r by

Conway. (") The l abo ra to ry -s i ze u n i t was 20 i n . long by 20 i n . wide by

20 i n . high. He found t h a t t he uranium l o s s was very s e n s i t i v e t o f l o w

r a t e a t 25OC g i v i n g waste losses o f 1% a t 50 ml/min and 8% a t 400 ml/min.

There appeared t o be no e f fec t o f f l o w r a t e a t 50 o r 60°C w i t h waste

losses being constant a t 0.7 and 0.1%, respec t i ve l y . He a l so found t h a t

both capac i t y and e f f i c i e n c y were a s t rong f u n c t i o n o f r o t o r speed as

shown i n Table 41. When the u n i t was operated w i t h t h e aqueous phase

continuous, t h e uranium l o s s was tw ice as h igh as when the organic phase

was cont inuous. When the aqueous-phase-to-organic-phase f l o w r a t i o was

decreased from 1.5 t o 1.0, t he uranium l o s s increased from 0.1 t o 2.0%.

TABLE 41. The E f f e c t o f Rotor Speed on Waste Loss - Podbiel n iak E x t r a c t o r

Rotor Speed, Maximum Capacity, Waste Loss, RPM ml /mi n a/

/o

5000 450 0.1

3000 300 1.3

Purex F i r s t Cycle Ex t rac t i on Condi t ions

A Podbie ln iak Model 5000 "Pup" e x t r a c t o r having the o v e r a l l dimen-

sions o f 54 by 24 by 30 i n . h igh was tes ted by Morgenthaler (78) under

Purex F i r s t Cycle e x t r a c t i o n cond i t ions . The opera t ion was c a r r i e d ou t a t

feed ra tes o f up t o 400 gpm and r o t o r speeds up t o 5000 rpm. Uranium i n 2 the r a f f i n a t e was found t o be a f u n c t i o n o f ~ p / w where ap i s t he pressure

drop across t h e motor and w i s t he r o t o r speed. I n a d d i t i o n , holdup was 2 a1 so a f u n c t i o n o f ~ p / w . A t values o f ap/w2 = ( 2 x 1 o - ~ t o 5 x

2 2 [ l b f o r c e l i n . ] [min/sec] no f l o o d i n g occurred. The u n i t showed 0.5

t r a n s f e r u n i t s (1 .5 t h e o r e t i c a l s tages) .

2 E x t r a c t i o n was found t o improve as: 1 ) ~ p / w decreases, 2) f l o w r a t e

decreases, and 3 ) r o t o r speed decreases.

The lowest uranium loss was 0.05% a t a flow ra t e of 200 ml/min, 3500 rpm rotor speed and a A ~ / W ' = 2.5 x 1 o - ~ .

Pressure Drop Correlation

-. Beyer ( I4 ) conducted t e s t s on the system boric acid-isoamyl a1 coho1 - * _ water using a Podbielniak "Pup" centrifugal extractor. The u n i t was 54 i n .

by 24 i n . by 30 i n . high, and had a rotor holdup of 529 cm3, an extractor 3 holdup of 638 cm3, and a capacity u p t o 450 cm /min sum -of the phases.

3 With a heavy phase flow of 100 cm /min, and a l igh t phase flow of 3 100 cm / m i n , 2.5 stages were obtained, and there was no dependence on rotor

3 speed in the range of 3000 to 5000 rpm. W i t h a heavy phase flow of 100 cm / 3 m i n and a l i gh t phase flow of 200 cm Imin, 4.5 stages were obtained a t

the above rotor speeds.

The l i g h t l iquid out pressure drop agreed with the following correlation:

where ~p = phase density difference, g/cm 3

w = rotor speed, rev/min r = rotor radius, i n .

VRHL = rotor holdup of heavy l iquid, cm 3

Centrifugal Contactors - Operating Characteristics

In a l a t e r paper, Jacobsen and Beyer (61 ) expanded on the i r original work. The advantages of centrifugal contactors are tha t they can operate with a low specif ic gravity difference, have a low holdup and a high throughput. These combine to permit a very rapid approach to equilibrium.

Centrifugal contactors a re different from column contactors in that . . the se t t l ing ef fec t of density difference i s multiplied by centrifugal

force and liquids accelerate and decelerate radial ly and e i ther process creates turbulence. Jacobsen and Beyer point out that flooding of centr i - fugal contactors can occur when the throughput i s excessive or by movement

of the principal interface to e i ther the i n l e t or the out le t points.

For t h e c o n t a c t o r and chemical system used i n t h e s tud ies , t h e f l o o d -

i n g l i m i t s can be p r e d i c t e d by t h e f o l l o w i n g equat ions:

= 4.86 x w2 l b f o r c e / i n . 2 ( P ~ o ) h e a v y phase f l o o d i n g

= 0.447 x w2 l b / i n . 2 ( P ~ o ) l i gh t phase f l o o d i n g

E x t r a c t i o n s tud ies demonstrated t h a t f o r PLo = 20 t o 80 ps ig , a f l o w 3 r a t i o O/A = 1.5 t o 2 and a t o t a l f low equal t o 250 t o 300 cm /min, two t o

t h r e e t h e o r e t i c a l stages were achieved i n t h e con tac to r . For f l o w r a t i o s

(O/A) i n t h e range of 48 t o 66 and t o t a l f low r a t e s between 275 and 345 3 cm /min, two stages a r e ob ta ined a t PLo 100 p s i and f i v e s tages a t PLo =

20 p s i .

5.0 MISCELLANEOUS CONTACTORS

MISCELLANEOUS CONTACTORS

A wide variety of contacting devices a re available i n addition to those mentioned i n the preceding sections. Examples of these include: packed columns, spray columns, baffle columns, perforated plate columns and rotating disc contactors as typified by the Sheibel and Oldshue- Rushton Column. Studies involving these devices will be summarized i n the fo l l owing subsections.

5.1 COMPARTMENTED, AGITATED COLUMN

01 dshue (83) descri bes an extraction column compartmented by horizontal plates, agitated by mixing impellers on a vertical shaft , and baffled by vertical members. The u n i t consisted of a 6-in. I.D. column which contained a 2 - i n . diameter impeller between plates spaced 3 to 6 in. apart having centered holes 2 118-in. diameter or 3 1/4-in. diameter. Impeller speeds ranged between 200 and 750 rpm.

Acetic acid was extracted from water to methyl-isobutyl ketone, and also from the ketone to water i n a counter-current manner using the column with different-sized compartments, impellers, impeller positions, impeller speeds, acid concentrations, and feed rates . Set t l ing zones were provided above and below the mixing-extracting compartments, and no coalescence was allowed between compartments.

2 Throughputs as h i g h as 4400 1 b / ( f t ) ( h r ) were investigated. The best stage efficiency showed a m i n i m u m height for a theoretical contact stage

2 of 37 i n . f o r a throughput of 2140 I b / ( f t )(hr) using eight compartments, each 3 in. high. This corresponds to a stage efficiency of 81%.

A comparison of the HETS values obtained i n t h i s work as well as w i t h

a Shei be1 column and a packed tower a re shown i n Table 42. A suff ic ient number of runs were made to define the effects of changes i n a number of column parameters :

TABLE 42. Comparison o f Typical Results o f High Capacity Ex t rac t i on Towers Using the System Methyl Isobuty l Ketone, Water and Acet ic Acid

The d e t a i l s o f column performance l i s t e d below are the best r esu l t s repor ted under the operat ing cond i t ions invest igated.

Type o f Column

M u l t i p l e mix ing compartments t h i s work




Schei be1

Schei be1

Packed

Diameter o f

Column, in .

6

De ta i l s o f Column

4 stages, 3- in . high, 2-118 i n . opening, 2 i n . turb ines, centered i n conpartment.

8 stages, 3-in. high, 2-1/8 i n . opening, 2-in. turbines, centered i n compartment.

8 stages, 3- in. high, 2-118 i n . opening, 2-in. turbines, centered i n compartment.

6 stages, 3-in. high, 3-114 i n . opening, 2 i n . turb ines, centered i n con~partment.

13 stages, 112-in. mixing section, 2-in. packing height

3 stages, 3-in. mix ing section, 9-in. packing height

66 in . h igh

Approx. Conc. o f

I n l e t Water Streams, %

3

Minimum HETS

f o r W + K

3.9

Throughput To ta l

Streams 1 b / f t2-hr

21400

( a ) Optimum. Higher throughputs can be obtained bu t stage e f f i c i e n c i e s a re lower.

plate f ree area - higher f ree area resulted i n lower efficiency, impeller diameter - a 3-in. diameter impeller was no bet ter than one 2 - i n . i n diameter, and plate spacing - a 3 in. spacing had higher resu l t s i n lower HETS

val ues than 1 arger spacing . These observations appeared to be indifferent to the direction of solute t ransfer , i . e . , and from water to ketone or vice versa.

A correlation was established to re la te power requirements t o operating variables:

k 3 5 P = - p N D . 9

where D = turbine diameter, f t

N = rotor speed, rpm p = average density of mixed liquids, I b / f t 2

g = gravity constant k = 4.4 from four-bladed impellers

5.2 PERFORATED PLATE CONTACTOR

A unique extraction column i s described by Garner. (51) The 4-in. I.D. column had eight s ta in less steel or polyethylene plates. Each plate had

59 1/8-in. diameter holes which gave a f ree area of 6%. An upcomer, extending ei ther 2 or 4 1/2 in. above the plate , accounts for an additional 5% f ree area. Tests were carried out using the water-toluene- diethylamine system. The resu l t s of the t e s t s are summarized in Table 43.

I t i s apparent tha t the stage efficiency ranged from 2 to 15%. HTUoe were found to range from 2 t o 50 f t . Garner found tha t :

a t the same flow ra t e , the efficiency was 25 to 30% higher w i t h

polyethylene plates , both types of plates showed a higher Rca value fo r transfer from the

continuous to the dispersed phase, and the best performance was obtained when operating w i t h the aqueous phase

dispersed i n the t ransfer of solute from organic to aqueous, and w i t h

polyethylene plates.

TABLE 43. Tests Perforwed i n 4- in . Dia Column

Average Continuous

No. Phase ra te , o f Runs Upcomer Phase Transfer f t 3 /

Performed P la te Type Height, in. Dispersed D i rec t ion ( f t 2 ) ( h r ) Comments on Ef f i c iency

3 Metal 4 1/2 Water W ;t T 56.5 2-3% poor d i spersi on.

4 Metal 4 1/2 Water W + T 21.0 7-8% poor d i spers i on. Low so lu te t ransfer , but extreme turbulence.

5 Me t a 1 4 1/2 Water T -t W 21.0 8-1 1 % poor dispersion. Extreme turbulence o f dispersed phase.

4 ~ o l y e t h y l e n e 4 1/2 Water W + T {: :: z:::) 2-3% low solute t rans fer

4 Polyethylene 4 1/2 Water T + W 21.0 7-1 5% good drop1 e t re1 ease

1 Polyethylene 4 1/2 Water T - t W 75.4 Good drop1 e t re1 ease

15 Polyethylene 2 Water W + T 21.0 3-7% low so lu te t rans fer

7 Polyethylene 2 Water T W 21.0 7-1 5% good drop1 e t re1 ease

5.3 COMPARISON OF EXTRACTION COLUMN PACKING

Jacques (62) conducted t e s t s using: extraction column packi ngs of 1/2 and 3/4-in. diameter spheres, 0.25-in. Raschig rings, 0.25-in. polyethylene pe l le t s , 0.75-in. spheres randomly packed i n an orthorhombic

arrangement and i n a rhombohedra1 arrangement. His conclusions f o r two phase flow were:

Flooding occurs a t a continuous phase velocity (Vc) which i s a t the

high end of the laminar flow range. Longitudinal Peclet numbers [(y) (?)I a re always smaller than or equal to the laminar value for one phase flow. Axial Peclet numbers of the continuous phase decrease w i t h decreasing

V C and w i t h increasing discontinuous phase velocity ( V D ) .

Axial Peclet numbers of the discontinuous phase increase w i t h increas-

i n g V D b u t decrease w i t h decreasing V c .

Radial Peclet numbers follow the same behavior as above b u t the varia- t ions a re smaller.

2 The resul ts can be correlated by NPe/(NPe)o s ( U o ) D / ( U o ) c

NPe = observed Peclet number. (NP,), = corresponding Peclet number for laminar region single phase

flow. (Uo)D, (U,), = flow ra te of continuous and discontinuous phases.

The low values obtained [(NP,), = 0.21 indicate tha t eddy diffusion

phenomena have a f a r reaching ef fec t on extraction.

5.4 PACKED COLUMN HOLDUP

Using a 2-ft length of 4-in. diameter pipe with the systems carbon tetrachloride-water and ethylene dichromide-water, column holdup was determined and correlated fo r Raschig Ring and Intalox saddle packings. Johnson (68) correlated the data t o produce the equation below:

where x = fractional holdup Uc = superficial velocity of continuous phase, ft/hr U D = superficial velocity of discontinuous phase, f t / h r .

The constants A and B i n the equation are l i s t ed i n Tables 44 for values of r of 0.62 for Raschig Rings and 0.12 for Intalox saddles.

TABLE 44. Values of Constants in Johnson's Holdup Equation

1/2 in . Raschig r i n g packinq

Systems A I3

Carbon t e t r ach l o r i de - water 0.023 0.00003 1

Ethylene d i ch l o r i de - water 0.0093 0.0001 52

Carbon t e t r ach l o r i de naphtha - water 0.01 14 0.000030

1/2 in . I n t a l ox saddle packinq

Carbon te t rach l .or ide - water 0.343 0.0000026

Ethylene d i ch l o r i de - water 0.248 0.00001 23

Carbon t e t r ach l o r i de naphtha - water 0.244 0.0000073

x X 3 For spray towers the equation suggested a correlation of (-) . This has been tested using data previously published by one of the authors and found to have only 1 imited use.

5.5 COLUMN WITH HORIZONTAL TUBULAR JETS

A column ut i l iz ing uniformly spaced, horizontal tubular je t t ing and intake rings a t the center and periphery of several cross-sections i s described by Vermnel en. This uni t involves a large amount of rotating equipment and i t s value in radioactive service i s questionable.

5.6 PULSED ROTATING DISC CONTACTOR

The ef fec t of pulsing on a rotating disc contactor i s presented by Angel i no. He s ta tes tha t the maximum efficiency i s greater than for

pulsing alone. However, the data are very scattered. The device appears

to be complicated from a mechanical point of view.

6.0 COMPARISON OF CONTACTORS

COMPARISON OF CONTACTORS

Many types of liquid-liquid extraction contactors are used indus- t r i a l l y and many additional types have been tested i n the laboratory and proposed for large-scal e use. Since contactor use in radioactive service imposes severe res t r ic t ions on the complexities of the units t o be used, a large segment of the contactor population can be eliminated readily prior t o selecting a sui table candidate.

A number of studies have been made on viable contacting devices. These are compared in the following subsections. These studies indicate tha t pulse columns, mixer-sett lers, and centrifugal contactors a re the contactor types to be considered in the design of a nuclear separations plant based on solvent extraction technology. Each type may be considered proven, and each type has some advantages and disadvantages w i t h respect t o the other. Therefore, the choice to be made i s by no means clear-cut. I t must be made with a high degree of dependence on the background and particular needs of the user.

6.1 OPERATION, MAINTENANCE AND DESIGN CONSIDERATIONS

6.1.1 Packed Columns, Pulse Columns, Mixer Se t t le rs and Centrifugal Contactors

Jealous and Stewart (67) made an in-depth comparison of packed columns, pulse columns, mixer s e t t l e r s and centrifugal contactors as the contactor for the f i r s t cycle in the Purex Process. As shown i n Table 45, contactor operation, maintenance and design considerations were addressed. In the opinion of the authors, columns appear to be favored i n several categories, b u t mixer-settlers o r centrifugal contactors are favored in others. Thus, no clear-cut choice i s indicated.

6.2 OPERATION AND MAINTENANCE - PULSE COLUMNS VERSUS MIXER SETTLERS

During considerations of the contactor type t o be used i n the Hanford Purex Plant, two internal memoranda were prepared. The f i r s t by Webster (127)

reported tha t a mixer-settler type contactor i s slower to recover from an operating upset. Therefore, producing 1 arger quantit ies of off -specification

TABLE 45. Comparison o f L iqu id-L iqu id Ex t rac t i on Contactor Types

A. OPERATION

Operation

1. Start-up - Shut Down

Packed Column Pulsed Colu~nn !!E C-C - , 4 Volunie Changes

Pulse Columns S l i g h t l y Favored

2. Mechanical 1 In ter face 1 I F Columns Favored

M u l t i p l e I F Rotor speed and back pressure con t ro l l ed

3. D i f f i c u l t y o f s tar t -up a f t e r shut-down o f shor t dura t ion

Procedures adequate, no waste 4 l o ss increase. Equ i l ib r ium +

eas i l y recovered

Rapid start-up, no waste l oss

4. Extended Shut-Down Radiat ion Damage Radiat ion damage may be ., Minimal b appreciable Minimal r ad ia t i on damage

Columns Favored

Steady-State Operation

1. Types o f Maladjustment no t comnon t o a l l

Var ia t ion o f i n te r f ace Var ia t ion o f i n te r f ace Va r i a t i on o f i n te r f ace pos i t i on pos i t ion . Loss o f pulse pos i t i on and a g i t a t o r

genera t o r speed

Va r i a t i on o f r o t o r speed and back pressure

2. Mechanical cont ro l and adjustment requ i red

One IF cont ro l One I F cont ro l and simple Several IF pos i t ions. instrumentat ion f o r pulse Simple instrumentat ion generator requ i red f o r a g i t a t o r

Simple instrumentat ion f o r r o t o r d r i v e and back pressure

Packed Column S l i g h t l y Favored

B. MAINTENANCE

1. Plugging No problem ? ? May requ i re f l ush ing

Comparison Incomplete

2. Moving Par ts None Pulse generator M u l t i p l e a g i t a t o r and seals

Seals r o t o r bearings

3. E l e c t r i c a l serv ice

4. Total Replacement

None Pulse generator M u l t i p l e c i r c u i t s f o r ag i t a to r mechanism

Simple c i r c u i t f o r prime mover

50'H. Replacenient poss ib ly Maximum he ight 27'. No Bulk and number o f con- by ex i s t i ng technology problem t rac tors . M u l t i p l e c l .

and instrument connections

Simple and easy

Packed co lu~ l~n expendable. Column expendable p la tes Un i t not expendable. Package hard t o decon. easy t o decontamir~ate f lush ing d i f f i c u l t , t o r -

turous

Low volume f l ush ing adequate. Un i t inexpensive

5. Ease o f decontaminat ion

TABLE 45. (contd)

Packed Column Pulsed Col untn

Rating: 1 Pulse Column. 2 Packed Column. 3 MIS

C. DESIGN CONSIOEW\TION

1. Lower l i m i t s o f dens1 t y 4 0.1 <0.05 r difference I n The Pures Process, The Chemical Condition For The Optimum Are Met By A l l

2. Size and geometry 16 in . 0 x 50 f t H 16 in . 0 x 27 f t H 10 f t x 4 f t x 16 f t 6 f t x Z f t x 2 f t (20 stages)

MS Do Not Require Deep Canyon

3. Holdup volume. gal 500 280 425

Small Holdup Advantageous For Short Downtimes

4. End section design + Methods Demonstrated + None Seals demonstrated

5. Capacity Demonstrated a t Not demonstrated a t 1.5 Capacity to 10,000 gpn + 1.5 TU/day TUlday avai lab le

6. Phase separation Satisfactory enulsion Pulsing enhanser phase set. Possible loss o f phase Centrifugal source w i l l a t small density e f f . and minimizes f looding from separation i s a serious break emulsion

foreign material problem

7. Pressure requirements 25 ps i

8. F l e x i b i l i t y

Unknown due t o f low Low reversal

75 ps i

Limited by Flooding Rates. Number Of Stages Stages can be added o r re- Variat ion o f motor speed

t And Stage Height. Column Length Can Be moved. Limited by f looding and pack pressure w i l l Modified Readily. Flow Below 15% of Flood- rates a t ag i ta tor spped accmodate 10 f o l d change ing I s I n e f f i c i e n t i n density d i f f e r e n t i a l

m a t e r i a l f o r a g iven upset. He a l s o repo r ted t h a t t h e r e a r e c e r t a i n con-

d i t i o n s under which a m ixe r s e t t l e r cou ld be operated from which c r i t i -

c a l i ty problems would a r i s e . A1 though s u f f i c i e n t i n f o r m a t i o n i s a v a i l a b l e

t o s p e c i f y t h e c e l l space requ i red f o r a m i x e r - s e t t l e r t ype contac to r ,

a d d i t i o n a l t e s t work would be requ i red t o f u r n i s h f u l l process i n f o r m a t i o n

on a u n i t s i zed f o r our proposed p l a n t . . . The second i n t e r n a l memorandum by Hollenbach (59 ) presented a compari-

son o f m i x e r - s e t t l e r s and pu lse columns f rom t h e s tandpo in t o f o p e r a b i l i t y

and maintenance. These cons idera t ions are g iven i n Table 46.

6.3 EFFICIENCY AND CAPACITY STUDIES - PACKED COLUMNS, PULSED AND UNPULSED

. E f f i c i e n c y and capac i t y s tud ies were c a r r i e d o u t by Russel l (93) in a

4- in . diameter pu l se column. The column was packed w i t h 112-in. ceramic

Raschig r i n g s f o r e f f i c i e n c y s tud ies , and the system:uranyl n i t r a t e : 20% TBP

i n Turpolene was used. HTU values from 6 t o 23 i n . were obta ined. He

concluded t h a t p u l s i n g improved t h e e f f i c i e n c y o f t he column by about

5 f o l d .

Capaci ty s tud ies u t i l i z e d the water-20% TBP systems i n Turpolene i n

a 4 - in . I D column packed w i t h s t a i n l e s s s t e e l Raschig r i n g s . It was found

t h a t t h e column had 140% o f t he capac i t y o f an unpulsed column a t an

ampl i tude-frequency product o f 30 in./min. However, t h e capac i t y decreased

t o 50% o f t h a t o f an unpulsed column a t an ampl i tude frequency product o f

75 in . /min. The d i f f e r e n c e cou ld n o t be explained.

6.4 HEAD ROOM VERSUS FLOOR AREA COMPARISON - MIXER SETTLERS VERSUS PULSE COLUMNS

Thornton ("O) compared 25 con tac to r types. F i r s t he d i v i d e d t h e

u n i t s i n t o t he f o l l o w i n g ca tegor ies :

Class 1A - V e r t i c a l column s h e l l s . Phases f l o w counter -cur ren t , one d i s - persed i n t h e o t h e r by a concen t r i c r o t a t i n g device.

Class 1B - D ispers ion produced by r e c i p r o c a t i n g o r p u l s i n g device.

Class I I A - Var ian ts o f m i x e r - s e t t l e r s except DeLeval and Luwesta which are c e n t r i f u g a l con tac to rs .

Class I I B - M i x e r - s e t t l e r s except t h a t mechanica l ly d r i v e n impe l l e r s a r e rep laced by e j e c t o r s .

TABLE 46. Comparison of Pulse Columns and Mixer-Settlers - The Effect on Operability and Maintenance

1. R e l i a b i l i t y o f Equipment

l a . Pulse Mechanism versus As many as 15-20 f r a c t i o n a l H.P. a g i t a t o r s per Only one mechanical u n i t per contactor , however, a g i t a t o r s (mechanical ) contactor. These a re d i r e c t d r i v e and over- u n i t conta ins wearing p a r t s such as reduc t ion gear

powered several times. Spare stages provided box, qear and rack, and rec ip roca t ing p i s t o n w i t h so t h a t loss o f a g i t a t o r s would n o t cause r ings . Unless pulse generator i s spared i n place. process d i f f i c u l t y and would a l low f o r a planned which involves remote va lv ing problems, f a i l u r e of shutdown f o r r e p a i r o r replacement. A l l ag i - u n i t causes imnediate shutdown f o r replacement. t a t o r s w i l l be i n "not" zone. Locat ion i n a co ld zone would a l low f o r a preventat ive

maintenance program. Ag i ta to rs a r e simple mechanical ly w i t h bearings and r o t a t i n g s h i f t being the on ly r e v o l v i n g parts.

Comnent: There has as y e t been no operat ing experience a t Hanford t o de te~mine the l i f e and r e l i a b i l i t y o f pulse generators, although several thousand t rouble- f ree hours have been accumulated on an experimental u n i t . S i m i l a r l y the re i s l i t t l e l i f e experience on pump mix a g i t a t o r un i t s . However, they a re made from standard designs which have been proven t o be r e l i a b l e i n indus t ry f o r many years.

M ixer -se t t le rs are more simple and rugged mechanical ly and should prove more r e l i a b l e based on the above points .

l b . Pulse mechanism versus Ag i ta to r meter speed con t ro l i s achieved by use o f Pulse generator frequency i s c o n t r o l l e d by a va r iab le a g i t a t o r s ( e l e c t r i c a l ) va r iab le frequency AC current . The speed o f a l l frequency AC cur ren t suppl ied by a s u i t a b l e generator.

a g i t a t o r s o f any one contactor can be varied.

Comnent: No appreciable d i f fe rence i s apparent.

l c . Columns versus mixer- M ixer -se t t le r i s a b a f f l e d box about 20 ft long Pulse column i s a maximum o f 20 i n . i n diameter s e t l e r boxes (mechanical ) x 6 ft long wide x 1 f t deep. No d i f f i c u l t i e s x 40 f t h igh w i t h per forated p lates. Mechanical ly

a re an t i c ipa ted . no d i f f i c u l t i e s are an t i c ipa ted .

C m e n t : No d i f fe rence i s apparent here.

Id. Rangeabil i t y o f throughput No data a re a v a i l a b l e regarding the range over which t h i s equipment may be operated; however, o ther fac to rs o f the contactor being equal, reasonably wide (2 o r 3 t o 1 ) operat ing ranges a r e required. No appreciable d i f fe rences a re

an t i c ipa ted between the mixer -se t t le r and pulse column contactors.

le . Ease o f s ta r t -up and Mixer -se t t le r has about 1/3 g rea te r volume; thus. Pulse columns have l e s s ho ld up. shut-down longer s ta r t -up and shut-down periods a re

ant ic ipated.

Comnent: Smaller hold-up i s of advantage on extended shut-downs and a lso f o r changes i n process condi t ions. Pulse columns a re s l i g h t l y favored here.

If. Columns versus mixer -se t t le r Each m i x e r - s e t t l e r contactor i s an i n t e g r a l u n i t . 18 pulse column i s s p l i t i n t o two sections, because o f (quan t i t y o f equipment) he igh t considerations, w i t h a d d i t i o n a l pump tank

required.

Cannent: M ixer -se t t le r favored by t h i s considerat ion.

TABLE 46. (contd)

2. Maintenance

2a. E f f e c t o f canyon height M ixer -se t t le rs a re low u n i t s and w i l l have no Pulse columns a re long u n i t s r e q u i r i n g c e l l depth e f f e c t as such on canyon he igh t and m y r e s u l t t o accomnodate them and a h igh crane f o r placement i n canyon he igh t reductions. and removal. C e l l bottom t o crane r a i l d is tances

i n excess o f 60 f e e t a r e regarded unfavorably.

Comnent: Unfavorable canyon heights i n case o f pulse columns i s a b i g p o i n t favor ing mixer s e t t l e r s . Excessive c e l l f loow t o crane' r a i l distance cannot be accepted.

2b. Accessab i l i t y and rep laceab i l i t y

Re la t i ve ly compact u n i t - because o f l eng th must Compact u n i t main problem i n height as above. Pulse be we l l braced however. Removal o f contactor box generator must be removed f i r s t . Removal expected t o expected t o be very in f requent . be very in f requent .

2c. E f f e c t o f pulse mechanism Not applicable. on a co ld zone.

Advantages: Allows contact and preventat ive maintenance t o prolong l i f e and enhance r e l i a b i l i t y o f operations.

Disadvanta es: A) Without i n s t a l l e d spare, f a i l u r e o f * pulser wou d s t i l l cause shut-dwon t i l l repai red o r replaced. B ) l o c a t i o n i n a "cold" zone would subject t h a t zone t o SUP condi t ions dur ing maintenance. and1 such a zone would probably end up contaminated.

Comnent: Unless a l l pulsed streams were "cold" streams, the removal o f the pulsers from the canyon t o a "cold SUP" g a l l e r y loses some of i t s at t ract iveness.

2d. B u i l d up o f s o l i d s i n As cur ren t l y conceived, m ixer -se t t le r u n i t s a re These u n i t s a re f lushable and dra inable. Plugging contactor u n i t . no t f lushable o r drainable. While t h e presence o f the s ieve p l a t e holes i s not an t i c ipa ted i n l i g h t

o f appreciable q u a n t i t i e s o f s o l i d s i n the system o f experimental operations. i s questionable a t present, f l u s h i n g and clean-out p e r i o d i c a l l y wi 11 be requ i red f o r accountabi 1 i t y reasons.

Comnent: Pulse columns are favored by t h i s point .

2c. F lushing and decontamination.

Not f lushable and drainable, thus no t r e a d i l y Flushable and dra inable bu t quest ion how successful subject t o decontamination espec ia l l y w i t h many decontamination would be beyond t h i s . Corners of corners. pockets. etc. p la tes and s e t t l i n g chambers would be impossible t o

c lea r .

Cormlent: S l i g h t advantage t o pulse columns; however, i n general, de~on tamina t ion and contact maintenance fo r repa i rs i s n o t contemplated fo r any type o f contactor. Vessel f a i l u r e n i l t o date. Replacement cos t would be on ly comparison basis.

These c o n t a c t o r s be1 i eved appl i cab1 e t o r a d i o a c t i v e s e r v i c e a r e shown i n Table 47 and a r e r a t e d according t o their s u i t a b i l i t y . On t h e b a s i s o f

this comparison, the more important c o n t a c t o r s were judged t o be pulsed and r o t a r y col umns and KAPL-type mixe r - se t t l e r s .

TABLE 47. Contactors f o r Radioact ive Serv i c e

Type of ~ y s t e m ' ~ ) a 6 Activity Only y Activity

Design/Geometrical Moderate Number Large Number Moderate Number Large Number Requirements Stages Required States Required Stages Required Staqes Required

Types 11A or 11B Type 11B Types l lAor l lB Type11B ~ W / O mech. seals)

Headroom 1 imi ted (1 ) Air pulsed (1)Airpulsed (1)Airpulsed (1 ) Air pulsed mixer-settl er mixer-settler. mixer-settl er mixer-settl er

(2) Mechanically (2) Mechanically (2) K.A.P.L. pul sed pulsed mixer-settl er mixer-settler mixer-settl er

(3) K.A.P.L. mixer-settl er Several column internal configurations

Types 1A or 1 B Type 1 B Type 1B Type 18 Floor area 1 imi ted (1 ) Air pulsed (1) Air pulsed (1) Air pulsed (1) Air pulsed

col umn co 1 umn column col umn (2) Mechanically ( 2 ) Mechanical ly

pul sed column pulsed column

(3) Rotary disc 01 dshue-Rushton Rotary annular

(a) (1) Refers to the most suitable type of contactor for a given duty. ( 2 ) Refers to a1 ternative contactors. (3) Refers to other possible alternatives which might prove to be

suitable subject to experimental confirmation.

6.5 CONTACTOR EFFECTIVENESS

C avid son(^^) has addressed c o n t a c t o r comparisons i n terms o f a s i z e - c a p a c i t y r e l a t i o n s h i p and w i t h regard t o c o n t a c t o r a d a p t a b i l i t y .

6.5.1 Size-Capaci t y Re la t i onsh ip

One o f t h e bases f o r comparison o f the e f f e c t i v e n e s s of var ious types o f con tac t ing dev ices i s the s ize-capac i t y r e l a t i o n s h i p . The volume

occupied by the equipment i s an impor tan t v a r i a b l e s ince space requirements

and f a b r i c a t i o n cos ts a re approximately p ropo r t i ona l t o t he volume. There-

fo re , i f the volume i s taken as the s i z e va r iab le , then a q u a n t i t a t i v e

measure o f t h e ef fect iveness cou ld be expressed as fo l lows:

where

CE = contac tor e f fec t iveness , throughput/volume, h r -

N = number o f t h e o r e t i c a l stages

F = t o t a l f l owra te , f t 3 1 h r .

V = To ta l contac tor volume

K = A dimensionless constant depending on the so l ven t -ex t rac t i on f l owsheet

Tm = residence t ime i n mix ing sec t ion , h r

TS = residence t ime i n s e t t l i n g sect ion, h r

I n terms o f t he va r iab les u s u a l l y considered i n packed-tower design,

t he above equat ion becomes

where

G =- mass f l owra te /un i t area, 1 b/ ( h r ) ( € t 2 )

Pave = average dens i ty , 1 b / f t 3

HETS = he igh t equ iva len t t o a t h e o r e t i c a l stage, f t

V i n = volume o f t he i n l e t sect ion, f t 3

VOut= volume o f disengaging sect ion, ft3

A = t o t a l cross-sect ional area o f t he column, ft2

h = he igh t o f packed sect ion, f t

A comparison of contactors, insofar as i s possible w i t h limited data, i s presented i n Tab1 e 48.

TABLE 48. Comparison of Contactors fo r the System Acetic Acid - Methylisobutyl Ketone - Water

Contactor Effectiveness,

Contactor hr-1 P U ~ D mixer-settl e r ( a ) 43 - 54

Vertical -stacked extractor ( b ) (Fenske) Turbine contactor (c

Packed towers 1 ) Pulsed 2 ) Not pulsed

Pul se col umns (perforated pl a t e ) Schei be1 col umn

( a ) Second f igure based on hydraulic data only. Efficiency data taken only a t lower flowrates ( f i r s t f igure) .

( b ) P i lo t plant u n i t ( c ) Estimated

6 . 5 . 2 Contactor Adaptabil i t y

The ideal contactor requires a minimum investment for both associated equipment and building. I t maintains a high efficiency over a wide range

of operating conditions, has a high capacity with low holdup, i s re l iab le i n operation w i t h simple controls and minimum maintenance requirements, and i s f lex ib le for process variations. The choice of a contactor for a particular process i s governed by the desire to include as many of these character is t ics as possible.

The investment requirement for the contactor and i t s auxi l ia r ies i s usually not a controlling item since the cost of the building, shielding,

instruments, and other process equipment i s f a r greater than the cost of the contactors. In many cases, however, the choice of a contactor influences the building design and indirect ly exerts an ef fec t on the overall investment.

6.6 DECONTAMINATION PARTITIONING AND WASTE LOSSES - MIXER SETTLERS VERSUS PULSE COLUMNS

A comparison of pulse columns and KAPL-type mixer-settl e r s has been

made by Darby (33) on radioact ive feed t o determine t h e i r r e l a t i v e perfor-

mance w i t h respect t o decontamination, pa r t i t ion ing and waste losses . The

dimensions of the pulse columns comprising the 1A Extraction, 1A Scrub,

1B Par t i t ion ing , 1B Scrub and 1C Stripping columns and t he s tage require-

nients f o r mixer-se t t lers having the same functions a r e l i s t e d i n Table 49.

TABLE 49. Pulse Column Versus Mixer S e t t l e r Comparison - Purex Process

Conditions : ( a

Pulse Columns: Throughput - 75 kg metal/day

Dia., Contacting ga l , Co 1 umn i n . Height h r / f t 2

1 A (Extract ion) 3 12 555 1A (Scrub) 3 18 460 1B (Pa r t i t i on ing ) 2.5 18 390 1B (Scrub) 2 8 190 1 C 4 12 31 0

Mixer S e t t l e r : Throughput - 7.4 kg metal/day

Bank Actual Stages

1 A (Extract ion) 12 1A (Scrub) 8 1 B (Par t i t ion ing ) 10 10 (Scrub) 10 1 C 10

Pulse Ampl. ,

i n .

0.98 0.98 0.75 1.08 0.56

Pul s e Frequency,

cprn

58 58 5 8 58 7 3

( a ) All pulse p la tes on 2-in. w i t h 1/8-in. diameter holes, 23% f r e e area per p la te .

I t was found t h a t the waste losses from the mixer-se t t ler banks was

lower and the decontamination was s l i g h t l y higher than provided by the

pulse columns. However, the pulse columns produced lower uranium contami-

nation i n plutonium and plutonium in uranium.

6.7 DESCRIPTION OF A VARIETY OF CONTACTORS

A description of 3/4-, I - , and 5-in. diameter pulse columns, a 1 -in. diameter profi 1 e pul se col umn, a concatenated pul se column, a midi-mixer- s e t t l e r , a mini-mixer-settl'er and a vertical ly safe mixer s e t t l e r i s given by Davidson. (36) Only a small amount of data i s included.

~ h i e l e ( ' 09) a1 so descri bed film type extractors, spray towers, baffle towers, perforated plate towers, packed towers and mixer-settl e rs . Direct comparisons fo r similar operations a re not given.

6.8 OVERVIEW - SOLVENT EXTRACTION CONTACTORS

A generalized treatment of several contacting devices including pulse columns i s presented by Treybal. ( I 1 5, No conclusions regarding the rela- t i ve merits of the contactors i s given.

6.9 EFFICIENCY, ENERGY INPUT, HOLD-UP TIME, AND OPERATING RANGE - MECHANICAL INPUT COLUMN VERSUS MIXER SETTLERS

Cool ey (30) collected scattered data to give a very rough comparison of the general character is t ics of some of the contacting devices and drew the following generalizations:

From the efficiency standpoint most of the columns tha t use mechanical

energy i n p u t t o a t t a in dispersion can achieve similar eff ic iencies under cer tain operating conditions peculiar to each individual u n i t .

Efficiency increases (reductions i n overall column heights) approaching a factor of 3 over nonmechanical input units such as packed columns can be obtained.

Mechanical i n p u t columns such as pulse, sieve and rotating disc can approach a capacity advantage of a t l eas t 2 , while maintaining efficiency.

Although dependent on the particular design, the hold-up or contact

times (sum of b o t h phases) a re generally under 1 min/stage for

. I

mechanical energy i n p u t columns w h i l e nonmechanical i n p u t columns I

approach 2 m i d s t a g e w i t h some as h igh as 5 t o 10 min. Mechanical I

m ix ing u n i t s o f m i x e r - s e t t l e r s genera l l y cover t he range above 1 min . I I

. . I

depending on the design. S e t t l e r s genera l l y have 1 t o 5 min holdup l

and te rmina l disengaging sect ions a r e designed f o r 5 t o 20 min holdup. ? I

The holdup o f t he d ispersed phase w i l l range from 30 t o 80% of phase 1

summation v a l ues . The wider e f f i c i e n t opera t ing range, approaching a f a c t o r o f 2 o f a . I

pu lse and c e r t a i n a g i t a t e d columns o f f e r some advantage as w e l l as I

mechanical simp1 i c i t y over mixer s e t t l e r s . I

' I

Other comparisons and choices a r e apparent ly made on the bases o f s o l i d s

content, holdup and k i n e t i c s . The f i n a l choice, t o a l a r g e ex ten t ,

appears t o be c o n t r o l l e d by f a m i l i a r i t y and i n d i v i d u a l preference.

6.10 ADVANTAGES AND DISADVANTAGES - MIXER SETTLERS, PACKED COLUMNS, PULSED

COLUMNS AND CENTRIFUGAL EXTRACTORS

A survey o f t he advantages and disadvantages o f a v a r i e t y of contac t -

i n g u n i t s by Ake l l ( ' ) produced the f o l l o w i n g r e s u l t s :

M i xe r -Se t t l e rs

Advantages Disadvantages

1. Good con tac t i ng 1. Large holdup 2 . Handles wide f l o w r a t i o 2. High power cos ts 3. Low headroom 3. High investment 4. High e f f i c i e n c y 4. Large f l o o r space 5. Many stages 5 . I n te rs tage pumping may be 6. Re1 i a b l e scale-up requ i r e d

D i f f e r e n t i a l Contactors ( a ) (Not mechanical l y a ided)


1. Low i n i t i a l cos t 1 . Limi t ed throughput w i t h small 2. Low opera t ing cos t dens i t y d i f f e rence 3. Simp1 e s t cons t ruc t i on 2 . Cannot handle wide f l o w r a t i o

3. High headroom 4. Sometimes low e f f i c i e n c y 5. D i f f i c u l t scal e-up

(a ) Packed o r s ieve p l a t e columns.

Differential ~ o n t a c t o r s ( ~ ) (Mechanical ly aided) Advantages Disadvantages

1. Good dispersion 1. Limited throughput with small 2. Reasonable cost gravity difference 3. Many stages possible 2 . Cannot hand1 e emu1 sifying 4. Relatively easy scale-up systems

3 . Cannot handle high flow r a t i o

Centrifugal Extractors


1. Handle 1 ow gravity 1. High i n i t i a l costs difference 2. High operating cost

2. Low holdup volume 3 . High maintenance cost 3 . Short holdup time 4. Limited number of stages in 4. Low space requirements single u n i t 5. Small inventory of solvent

6.11 GENERALIZED COMPARISON - MIXER SETTLERS, PACKED COLUMNS AND

PERFORATED PLATE COLUMNS

In a l a t e r treatment of the subject mixer-sett lers, packed towers and perforated plate towers, Treybal ( ' I 7 ) concl udes tha t :

Mixer s e t t l e r s a re f ree of back-mixing and can produce stage

eff ic iencies of greater than 90%.

Packed towers are intractable devices which suffer from end effects

and back-mixing, Perforated plate columns are not subject t o back-mixing. Extraction occurs during drop formation, the passage of the drops through the continuous phase, and drop coalescence. For best resu l t s , neither the trays or the column wall should be wetted by the continuous phase.

6.12 THE EFFECTS OF AXIAL DISPERSION ON COLUMNAR-TYPE CONTACTORS

The influence of axial dispersion, defined as a group of local effects which occur uniformly along the path of counter-flowing l iquids, on the

separating efficiency of a variety of columnar contacting devices was

studied by Vermeulen e t a l . 20) The experimental data and correlations

( a ) Pulsed columns - rotating disc contactors or Schei be1 columns.

made by a number of investigators has been compiled and are compared. Con-

tactors considered included rotating disc , spray towers, packed towers and

pulsed columns. I t was concluded tha t axial dispersion i n one or both of

the counter-flowing phases can reduce performance of contactors by a sub-

s tant ia l amount.

6.13 COMPARISON OF OPERATING A N D DESIGN VARIABLES AND COST - MIXER SETTLERS PULSE COLUMN AND CENTRIFUGAL CONTACTOR

Bernard ) compared the fol 1 owi ng contactor types :

a mixer-settler which can be easi ly sized and accepts high flow ra tes .

Liquid holdup i s high and one mechanical unit per stage i s required. pulse columns which are easi ly bu i l t , have a low holdup and reach

equilibrium rapidly. The extrapol ation from laboratory data t o large

scale i s d i f f i c u l t .

a centrifugal contactor which has a short residence time, low holdup

and can be s tar ted up or shut down rapidly.

Estimated re la t ive construction costs for a plant to process 5 tons of

uraniumlday would be:

Mixer-settler: 1.10

Pulse column: 1.05

Centrifugal contactor: 1 . O

Insofar as operating costs a re concerned: 1 ) labor costs are about the same for each, 2 ) higher e lec t r ica l costs for a centrifugal contactor i s

counterbalanced by a reduction in plant ventilation costs , 3) a i r consump-

tion i s higher f o r pulse columns; maintenance costs were not estimated.

6.14 COMPARISON OF RESIDENCE TIME - MIXER SETTLERS, PULSE COLUMNS AND CENTRIFUGAL CONTACTORS

Warner e t a l . ( l 2 ' ) performed irradiat ion t e s t s on TBP and concluded

tha t because of the re1 at ively long residence time, mi xer-sett l e r units

were not sui table for irradiated fuel processing due to degradation of the

TBP. On the other hand, the shorter residence time in pulse columns and

centrifugal contactors make such contactors a more favorable choice. Tests

carr ied out i n a minature pulse column (about 0.5-in. diameter w i t h p la tes

spaced 1 inch apa r t ) gave a f i r s t cycle uranium decontamination f ac to r of 5 3 2 . 3 x 10 and a f i r s t cycle plutonium decontamination f ac to r of 7.5 x 10 .

7 . 9 AIiN3TATE;I ZIBLIOGRAPIiY

FOR THE LITERATURE REVIEW OF SOLVENT EXTRACTION CONTACTORS

7.0 ANNOTATED BIBLIOGRAPHY

FOR THE LITERATURE REVIEW OF SOLVENT EXTRACTION CONTACTORS

by Bob Geier

1. Ake l l , R. S., "Solvent Ex t rac t ion : Ex t rac t i on Equipment Ava i l ab le i n t h e U.S." Chem. Eng. Prog., g:50-55, September 1966.

A survey was made of t he advantages and disadvantages o f a v a r i e t y o f contac t ing un i t s . Contactors i nves t iga ted were m ixe r -se t t l e rs , nonmechanically aided d i f f e r e n t i a l contactors and cen t r i f uca l contactors.

2 . Angel ino H. and J. ~ o l i n e r , "Study o f Back Mix ing E f f e c t i n a Pulsed Rota t ing Disc Contactor." ISECi71, - 1:688.

The e f f e c t o f pu l s ing on a r o t a t i n g d i s k contactor i s determined. Scat tered data i s presented t o show t h a t e f f i c i e n c y i s h igher than f o r pu l s ing alone. Mechanically, the device appears t o be very complicated.

3. Atwoody J. M. and 0. H. Koski, Automatic Contro l o f a Pulsed Column Bat tery. HW-SA-3237, Northwest Regional Meeting o f AIChE, Port land, OR. October 10, 1963.

An automatic c o n t r o l system f o r pulse columns i s described t h a t would minimize losses o f p lutonium from e x t r a c t i o n columns. Magnetic f l o w meters, e l e c t r o n i c d i f f e r e n t i a l pressure c e l l s , and neutron count ing devices are employed.

4. B a i l l i e M. G. and R. C. Cairns, Development of a Ten-Stage Mixer S e t t l e r f o r ~ 2 3 5 Solut ions. P a r t I I. AAECIE-56, Atomic Energy Cormissi on Research Establishment, Lucas Heights, New South Wales, Aust ra l ia , December 1960.

The e f f e c t s o f operat ing va r iab les ( f l o w ra te , impe l l e r speed and i m p e l l e r he ight ) i n a 10-stage mixer s e t t l e r a re reported. Stage e f f i c i e n c i e s ranged from 80 t o 95%.

5. B a i l l i e , M. G . and R. C. Cairns, Development o f a Ten-Stage Mixer- S e t t l e r f o r u~~~ So lu t i ons P a r t I . AAEC/E-56, Atomic Energy Commission Research Establishment, Lucas Heights, New South Wales, A u s t r a l i a , December 1960.

The development o f a 10-stage mixer s e t t l e r i s presented. Experimental work i s repo r ted and design recommendations f o r m i x e r - s e t t l e r s a r e given.

I

6. B a i l l i e , M. G., Pulse Columns i n Nuclear Fuel Reprocessing. P a r t 1. L i t e r a t u r e Survey. AAEC/E-50, Atomic Energy Commission Research Establ ishment, Lucas Heights, New South Wales, A u s t r a l i a , May 1959.

A l i t e r a t u r e survey and general overview on pu lse columns i s g iven a long w i t h the e f f e c t s o f design and opera t ing va r iab les on f l o o d i n g and mass t rans fer . Various c o r r e l a t i o n methods a r e a l so discussed.

7. Baird, M. H. I. and G. M. R i tcey, "Proceedings I n t e r n a t i o n a l Solvent E x t r a c t i o n Conference." ISEC174, 2:1571, Proceedings o f t he Soc ie ty o f Chemical Indus t ry , London, 19747

A i r d r i v e n pu lsers f o r e x t r a c t i o n columns a r e discussed and several a p p l i c a t i o n s given, i n c l u d i n g t h e i r use i n uranium p u r i f i c a t i o n .

8. Behmoiras, J., e t a l . , "Performance o f Pulsed Sieve-Plate E x t r a c t i o n Columns Dur ing the Separat ion o f Uranium from Thorium." Ind. Eng. Chem., Process Design Develop., 1(1):64-68, January 1962.

Tes t were conducted t o determine t o what degree thor ium cou ld be removed f rom uranium i n a scrub sect ion. It was found t h a t w i t h uranium concentrat ions above 116 g / i the removal dropped dramat i - c a l l y . Probable causes f o r t h i s a re given.

9. Belaga, M. W. and J. E. Bigelow, E f f e c t o f Pulse Column Operat ing Var iab les on H.T.U. (KT-133; EPS-K-181) , Thesis, Massachusetts I n s t . o f Tech. Engineering P rac t i ce School, Oak Ridge, TN, - - January 11 , 1952.

The e f f e c t o f pu lse he igh t and frequency v a r i a t i o n s on HTU values were s tud ied and i t was determined t h a t these opera t ing va r iab les i n d i r e c t l y a f f e c t e d the HTU.

10. B e l l , R. L . and A . L . Babb, "Holdup and Axial D i s t r i b u t i o n of Holdup i n a Pulsed S i eve -P la t e Solvent Ex t r ac t i on Column." I&EC Process Design and Develop., g ( 3 ) : 392-400, J u l y 1969.

Based on r e s u l t s ob ta ined i n a 2-i n. d iameter pu l se col umn with s t a i n l e s s s t e e l p l a t e s , a x i a l d i s t r i b u t i o n a c r o s s t h e column was shown t o be e s s e n t i a l l y cons t an t with r e s p e c t t o he ight . A holdup c o r r e l a t i o n i s included.

11. Bernard, C . , e t a1 . , "Experience wi th Cont r i fuga l Ex t r ac to r s : Comparison wi th Other Types of Ex t r ac to r s . " ISECt71, 2:1282. - The des ign and ope ra t i on of a Robatel c e n t r i f u g a l c o n t a c t o r is descr ibed . A comparison of t h e s e con tac to r types is given and i t i s concluded t h a t c e n t r i f u g a l con tac to r s can be s a t i s f a c t o r i l y use 1 i n nuc l ea r f u e l s reprocess ing . Overal l decontamination was 5 x 10 .

12. Berns te in , G . J . , e t a l . , Development and Performance of a High Speed, Long-Rotor Cent r i fuga l Contactor f o r Appl ica t ion t o Reprocessing LMFBR Fuels . ANL-7968, Argonne National Laboratory, Argonne, IL, January 1973.

Performance t e s t s were run on a long r o t o r c e n t r i f u g a l c o n t a c t o r t o determine t h e c a p a c i t y and e f f e c t s of ope ra t i ng v a r i a b l e s . In one t es t Mn02 added t o t h e s o l u t i o n a l l came through wi th t h e aqueous phase of s t ayed on t h e r o t o r . S tage e f f i c i e n c i e s of 95 t o 100% were obtained.

13. Be r s t e in , G. J . , e t a l . , Development and Performance of a High-Speed Annular Cent r i fuga l Contactor . ANL-7969, Argonne National Laboratory, Argonne, IL, January 1973.

A Savannah River c e n t r i f u g a l c o n t a c t o r was modified t o o p e r a t e wi th annu la r mixing. T e s t s were run on t h e u n i t t o determine i t s c a p a b i l i t i e s and l i m i t s . The annular design e a s i l y lends i t s e l f t o remote maintenance. S u f f i c i e n t mixing was ob ta ined wi thout a paddle o r s h a f t .

14. Beyer, G. H. and F. M. Jacobsen, Operating C h a r a c t e r i s t i c s of a Cent r i fuga l Ex t r ac to r . (ISC548), Ames Laboratory, Arnes, IA, November 26, 1954.

The ope ra t i ng c h a r a c t e r i s t i c s of a Podbielniak "Pup" e x t r a c t o r a r e i n v e s t i g a t e d . The v a r i a b l e s s t u d i e d were d e n s i t y d i f f e r e n c e , r o t o r speed, l i g h t - l i q u i d - o u t p r e s su re flow r a t e s , holdup and number of s t a g e s . The d a t a was c o r r e l a t e d i n an equa t ion .

15. Bloom, J . L . and L. D. Christensen, "A Four-Stage Prototype Mixer- Se t t le r . " (LRL-52), Cal ifornia Research and Development Co. Livermore Research Laboratory, Livermore, CAY Contract AT(11-1)-74, September 1 953.

The ef fec t of baffling and pumping paddle arrangement,or efficiency i s determined in a 4-stage mixer-settler with rotor speeds between 1200 and 2500 rpm and throughputs between 10 and 150 ml/min. Sug- gestions are made for design of purex process mixer-settlers.

16. Bruns, L . E . , Air Pulser fo r H-1 Column. HW-68636, General Electric Co. Hanford Atomic Products Operation, Richland, WA, March 1 , 1961.

isc cuss ion and diagrams of possible a i r pulser systems for a plutonium recovery solvent extraction column are given. Advantages and disadvantages of a i r pulsers fo r plutonium extraction are discussed.

17. Bruns, L . E . , Recuplex Stage Height, Transfer-Unit Height, and Stage Efficiency Calculations. HM-22742, Hanford Works, Richland, W A Y November 16, 1951.

The method used to calculate height equivalent to a theoretical stage (HETS), the height of a t ransfer unit (HTU), overall stage efficiency ( E o ) and average Murphree stage efficiency ( E m ) i s presented.

18. Burger, L . L . , Solvent Extractor fo r Aqueous Solutions of Metal Sal ts . U.S. Patent 2,743,170, U.S. Patent Office, Washington, D C , April 24,

A countercurrent extraction column which employs timed solenoid values and pressurized feeds i s described. The rapid coalescence and redispersion of phases are said to lead to greater extraction e f f i - ciencies.

19. Burger, L . L . and L . H . Clark, The Valve-Actuated Pulse Column Design and Operation. HW-23141, Hanford Works, Richland, WAY December 3. 1951 .

A countercurrent extraction column which employs timed solenoid valves and pressurized feeds i s described. The rapid coalescence and redispersion of phases a re said to lead t o greater extraction e f f i - c i enci es.

20. Burger, L. L. and L. H . Clark, The Valve-Actuated Pulse Column-11. A Study of the Temperature Effect and Design Variables. HW-26459, Hanford Works, Richland, WAY February 16, 1953.

A detailed study of a valve actuated column under Purex conditions was carried out. The ef fec ts of operating and design variables on the efficiency of the column are reported.

21. Burger, L. L . , Effect of Temperature on Urani um Recovery Column Operation. HU-29001, Hanford Works, Richland, WA, August 12, 1953.

Temperature effects on the dispersion, coalescence, and net ra te of extraction in a pulse column are discussed. Supporting data are included.

22. Burkart, C . A . , e t a l . , Purification of Thorium Nitrate by Solvent Extraction w i t h Tributyl Phosphate. 11. Mixer-Settler Pi l o t Plant Investiqations. BMI-262, Battelle Memorial Ins t i tu te , Columbus, OH, July 31, 1952.

The construction and operation of three 10-stage mixer s e t t l e r units t o simulate the extraction-scrub-strip cycles for thori um purification with 30% TBP in kerosene i s described. Stage efficiences were 50% in the stripping section and 80% i n the extraction and scrub sections.

23. Burkhart, L. E. and R . W . Fahien, Extraction Efficiency of a Pulsed Column of Varied Geometry. ISC-860, Ames Laboratory, Arnes, IAy June 1956.

An investigation was made of the effects of plate spacing, hole diameter, precent-free area, pulse amp. and frequency on the extraction efficiency in a 1-in. diameter pulse column.

24. Burns, W . A . , e t a l . , The Design and Operation of the Pulse Column. HW-14728, Hanford Works, Richland, WA, October 1 2 , 1949.

A study demostrated the design, operation and performance of an experimental pulse column for the Redox Process.

25. Cavendi shy J . H . , "Reextraction of Uranium from Tri-n-Butyl Phosphate- Kerosene Solvent." NLCO-883, National Lead Co. of Ohio, Cincinnati , O H , August 30, 1963.

The re-extraction of uranium from 33.5 vol% TBP i n kerosene was investigated in a pulse column. The e f fec t s of operating and design var iables on colunln performance were discussed. I t was concluded t h a t s ieve pla tes should be used near the bottom and nozzle pla tes on top.

26. Chantry, W. A . , e t a l . , "Application of Pulsation to Liquid-Liquid Extraction." Ind. & Eng. Chem., 47:1153, June 1955. - A comparison of pulsing e f f ec t s on packed and sieve p l a t e columns i s given. Pulsing improved eff ic iency in both cases. Higher throughout b u t lower eff ic iency was obtainable in sieve p la te columns.

A 3-stage mixer s e t t l e r was operated to show the e f f ec t s of impeller speed on pressure drop, flow r a t e and efficiency. The overall ef f ic iency was over 90% a t 45 gal/min through the 10.5 foot long by 1 foo t square uni t .

28. Colven, T. J . , Equipment f o r Nuclear Fuel Reprocessing, DP-239, E. I . Du Pont de Nemours & Co., Savannah River Laboratory, Augusta, GA, October 1957.

Design information and preliminary operating cha rac t e r i s t i c s a r e given f o r a c r i t i c a l l y safe mixer s e t t l e r . The u n i t consisted of s i x stages with f l a t impellers capable of 700 rpm. Extraction eff ic iency was near 80%.

29. Conaway, J . E., "Solvent Extraction Studies: Evaluation of Podbielniak Centrifugal Contactor. " Quarter ly Report f o r May through July 1951 . CF-51-8-237, Oak Ridge National Laboratory, Oak Ridge, TN, August 24, 1951.

- .

A Podbielniak "Pup" extractor was operated to determine i t s useful- t

ness as a Purex 1-C contactor. The t e s t s were made on cold feed, and the r e su l t s were assumed t o be applicable to radioactive feeds. The need f o r fu tu re research on the subject i s shown. ..

30. Cooley, C. R a y Liquid-Liquid Solvent Extraction Contactors - A L i te ra tu re Survey, HW-74532, April 6, 1962.

A review of the s ta te-of- the-ar t i n solvent ext ract ion contactors i s given. The sca t t e red data gives rough comparisons of the contactors. I t appears t h a t t he author favors pulse-columns.

31. Co~pe r , V . R. and C. Groot, "Design Considerations f o r a Pulse Column System," March 9, 195Q, Solvent Extraction Equipment Evaluation Study. BNWL-2186; P t 1 , Battel l e Pac i f i c Northwest Laboratories, Richland, WAY January 1977.

An equation t o ca lcu la te the m i n i m u m value of the accelera t ion pressure i n the pulse leg of a pulsed extract ion column i s developed. I f the sum of the absolute pressures i s l e s s than the vapor pressure, cavi ta t ion wil l occur.

32. Coplan, B. V . , e t a l . , The "Pump-Mix" Mixer S e t t l e r . A New Liquid- Liquid Extractor, AECU-2639, Knolls Atomic Power Laboratory, Schenectady, N Y , 1953.

The design and operation of a mini mixer-se t t ler i s described. Throughout was 0.2 t o 0.5 gpm w i t h holdup times of 1 t o 2 m i n . Stage eff ic iency was 99% when l i g h t phase baffles were used.

33. Darby, D. O . , Comparison of Purex Process Results i n Mixer S e t t l e r s and Pul s e Col umns. CF-51-8-67-Del ., Oak Ridge National Laboratory, Oak Ridge, TN, August 13, 1951.

A comparison of pulsed columns and KAPL type mixer s e t t l e r i s given, and the r e l a t i v e performance w i t h respect t o decontamination, pa r t i - t ioning and waste losses was determined. No c l ea r cu t choice i s imp1 ied.

34. Davidson, J . K . , e t a l . , Application of Mixer-Settlers t o the Purex Process, TID-7534, Book 1 , p. 130-151, 1957.

A pump-mix mixer-se t t ler is described, and r e s u l t s of p i l o t p lant f i r s t cycle Purex runs a r e given. Effects of i n su f f i c i en t mixing, backmixing and by-passing a r e discussed.

Davidson, J . K., Theory of the Pump-Mix Mixer S e t t l e r . KAPL-130, Knoll s Atomic Power Laboratory, Schenectady, N Y , March 11 , 1949.

An analyt ica l descript ion f o r the hydraulics, impeller operation, and operating cha rac t e r i s t i c s i s developed f o r a pump-mix mixer s e t t l e r w i t h the assumptions t h a t the mixed phase is uniform and a l l the aqueous phase s e t t l e s out i n each stage.

36. Davidson, J. K., 1 Engineering of Radiochemical Plants Contactors and Auxiliaries. KAPL-1808, Knolls Atomic Power Laboratory, Schenectady, NY, June 17, 1957.

Several variations of pulsed-columns and mixer-settlers were compared. Details of auxiliaries are discussed. Size-capacity relationships are developed with emphasis on total volume occupied.

37. Davis, A. T. and T. J. Colven, "The Effect of Mixer Design on the Efficiency of a Pump Mixer-Settler." AIChEJy - 7:72-77, March 1961.

The efficiency of simple and pitched paddles, marine propellers, and centrifugal and disk impeller was determined. Efficiency was correlated against impeller design and speed. Open impellers appeared I

superior to closed impellers.

38. Davis, M., "Mixer-Settler Extraction Equipment." Chem. Eng. Progr., 50:188-197, April 1954. -

A 1951 state-of-the-art comparison of mixer-settlers is given. The effects of operation and design variables are described. A detailed description of 12 types of mixer-settlers is included.

39. Davis, M. W., et al., Liquid-Liquid Extraction, AECD-3545; URCL-1013, Radiation Laboratory, University of California, Berkeley, CAY May 1953.

A 1951 state-of the-art comparison of mixer-settlers is given. The effects of operation and design variables are described. A detailed description of 12 types of mixer-settlers is included.

40. DeWitte, R., The Eurochemic Pulse Columns for Countercurrent Liquid- Liquid Extraction. Eurochemic Co., Mol, Belgium, 12:42-46, January 1966.

The pulse column battery for the Eurochemic process is described. An overview is given on pulse column performance, and control systems are discussed.

41. DeWitte, R. and L. Greens, The Influence of Purge Air Introduction on the Behaviour of a Pulsed, Perforated Plate Column. NP-14005, European Company for the Chemical Processing of Irradiated Fuels, Moly Belgium,

The effect of bottom interface detection purge air in a pulse column was studied. Pulse amplitude was decreased markedly in a membrane pulsed unit but no change occurred in an air pulsed unit. The air purge broke up the interface accumulation.

42. DeWitt, R . , e t a l . , Experiments Carried O u t i n the Eurochemic Extrac- t ion Column P i l o t Plant Concerning the Co-Decontamination Cycle Flowsheet. NP-13091, European Company fo r the Chemical Processing of I r radia ted Fuels, Mol, Belgium, October 1962.

Several pulse column car t r idge configurations were evaluated f o r use i n Eurochemic plant HA-HS columns. Data was given on several f i r s t cycle off-standard operating conditions and the time required t o de tec t a change in performance was noted.

43. Dierks, R. D. and N . P. Wilburn, Purex IC Column Cartridge Studies- Thin Fluorothene Versus Thick Linear Polyethylene f o r Sandwich Cartridge Use. H61-79717, November 25, 1963.

The e f f ec t s of t h i n (5132 i n . ) fluorothene and thick (3/4 i n . ) polyethylene s ieve p la tes sandwiched between some of the s t a in l e s s s t e e l nozzle p la tes i n a Hanford Purex IC column were studied.

44. Doyle, C. M . , Centrifugal Countercurrent Exchanger. U.S. Patent 3,292,850, U.S. Patent Office, Washington, DC, April 25, 1966.

A method i s explained whereby feed can be introduced to and a product discharged from a centrifugal contactor by the use of sleeve tubes. Use of t h i s method i s sa id to enhance the f l e x i b i l i t y of the con- t a c t o r .

45. Doyle, C. M . , "Centrifugal-type Contactors. " Chem. Eng. Progr., 64: 68-74, 1968. -

A horizontal sha f t centrifugal contactor capable of operating w i t h high feed r a t e s , a wide range of A/O flow r a t i o s , w i t h ro to r speeds of 500 t o 5000 rpm, and over a wide range of temperatures i s described and t e s t r e su l t s given.

46. Duckworth, J . P . , Applied Development of the Pulse Column, ISO-SA-6, Isochem Inc., Richland, WA, February 25, 1966.

An overview of the Purex reprocessing plant technology is given in which pulse columns, pumps, and in te r face control devices a r e d i s - cussed.

47. Durandet, J . , e t a l . , "Study of Pulsed Columns i n Solvent Extraction." Proceeding of the Second International Conference on the Peaceful Uses of Atomic Energy, 1959. Geneva, 1958, United Nations, New York, N Y , 17:180-191, 1959. -

The performance of pulsed columns f o r extraction of uranium from the HNO3 solut ion and re-extraction back i n to the aqueous phase were studied. The e f f e c t s of pulse amplitude and frequency, t o t a l flow r a t e w i t h A/O constant , hole diameter and choice of dispersed phase were evaluated.

48. Eugenio, M. R . , The Effect of Pulsation on Liquid-Liquid Mass-Transfer Resistances. ANL-5874, Argonne National Laboratory, Lemont, IL, July 1958.

Equations r e l a t i ng NTU values t o flow r a t e s and pulse frequency were developed in a 2 - f t high pulsed column w i t h a s ing le s t a i n l e s s s t e e l perforated pla te . . .

49. Figg, W . S . , Laboratory Studies of Two Pulsed Mixer-Settler Solvent Extractors. HW-28442, Hanford Works, Richland, WAY June 23, 1953.

A pulsed extract ion column having a mixing paddle between the p la tes i s described. Data from cold Purex t e s t s w i t h the column a r e given.

50. Friederichs, S. L . , e t a l . , Pulse Column Studies Using STR and SIR Feed Solutions. IDO-14312, Phil 1 ips Petroleum Co. Atomic Energy Div., Idaho Fa l l s , ID, September 27, 1954.

P i l o t p lant s tud ies were made t o determine operating cha rac t e r i s t i c s of pulsed columns proposed f o r reprocessing STR and SIR f u e l . Varia- t ions in the operating var iables resul ted in HTU values from 1 .5 t o 12 f t .

51. Garner, F. H . 9 e t a l . , "Perforated-Plate Extraction-Column Performance and Wetting Character is t ics . " AIChEJ, - 1 : 185-1 92, June 1955.

Results of t e s t s on a perforated p l a t e ext ract ion column w i t h upcomers extending above the p la tes a r e reported. Polyethylene and s t a i n l e s s s t e e l p la tes were investigated.

52. Geier, R . G . , Appl ica t ion of t h e Pulse Column t o t h e Purex Process . TID-7534, - 1:107-129, 1957. (HW-49542).

The e f f e c t of ope ra t i ng and design v a r i a b l e s a r e descr ibed f o r pu l se columns i n t h e Hanfod Purex process .

53. Geier, R. G. , "Improved Pul se Ext rac t ion Column Car t r i dges . " Proeeed- i ngs of t h e Second I n t e r n a t i o n a l Conference on t h e Peaceful Uses of Atomic Energy, Geneva, 1958. United Nations, New York, NY, 17~194-195, 1959. -

A v a r i e t y of pu l se column i n t e r n a l s and t h e i r ope ra t i ng c h a r a c t e r i s t i c s a r e descr ibed wi th r e s p e c t t o t h e i r u t i l i t y a s t h e p r inc ipa l c o n t a c t o r s o f a Purex s o l v e n t e x t r a c t i o n b a t t e r y . The a d a p t a b i l i t y o f pu l se columns t o a wide range o f a p p l i c a t i o n s i s d iscussed .

54. Goodle t t , C . B. , Performance of a Cent r i fuga l Mixer -Se t t le r a s a Phase Sepa ra to r . DP-1140, E. I . DuPont de Nemours and Co., Savannah River Laboratory, Aiken, SC, June 1968.

T e s t were run t o determine t h e capac i ty and e f f i c i e n c y of a cen- t r i f u g a l s e p a r a t o r . I t was found t h a t an i n c r e a s e i n ope ra t i ng tempera ture was needed a t h igher f low r a t e s t o maintain ~ 5 % entrainment .

55. Groenier , W. S. , e t a l . , Flooding i n Pe r fo ra t ed -P la t e Pulsed Ex t r ac t i on Columns: A Survey o f Reported Experimental Data and Cor re l a t i ons , and t h e P re sen t a t i on of New Cor re l a t i ons With Physical P rope r t i e s , Opera t i nq Var iab les , and Column Geometry. ORNL-3890, Oak Ridge National Labora- t o r y , Oak Ridge, TN, March 1966.

Data from many d i f f e r e n t pe r fo ra t ed p l a t e columns was compiled and c o r r e l a t i o n s made. No s i n g l e equa t ion gave no t i ceab ly b e t t e r success i n p r e d i c t i n g f low capac i ty . The equa t ion chosen by t h e au tho r p red i c t ed an average capac i ty 8.6% higher than experimental w i t h a s t anda rd dev ia t i on of 45.

56. Hami 1 t on , W. R . , Coalescence i n Pul se Col umns. HW-56281, General E l e c t r i c Co. Hanford Atomic Products Operat ion, Richland, WA, June 24, 1959.

The e f f e c t s of ope ra t i ng and design v a r i a b l e s on coa lescence were s t u d i e d wi th p a r t i c u l a r focus given t o con t ro l of t h e cont inuous phase by using polye thylene and s t a i n l e s s s t e e l s i e v e p l a t e s . P l a s t i c coa ted p l a t e d a r e a1 s o i n v e s t i g a t e d .

57. Hammond, V. L . , e t a l . , Pulse Generators for Solvent Extraction Columns. For presentation a t Regional Meeting of American Ins t i tu t e of Chemical Engineers, Ri chl and, MA, November 8 , 1962, October, 26, 1962. (HW-SA-2817)

A review of the operation of various types of pulsers (mechanical, electromagnetic, be1 lows and a i r pulsers) presents the re la t ive merits of each.

58. Hesson, G. M . , e t a l . , Organic Continuous Pulse Column Cartridqe fo r Purex A-Type Columns. HW-49181, March 22, 1957.

Tests were carried out to determine the optimum pulse-column cartr idge for organic phase continuous operation. Stainless s tee l and fluorothene plates were compared.

59. Hollenbach, F. A . , "Equipment Study," February 26, 1952, Solvent Extrac- t ion Equipment Evaluation Study. BNWL-2186; P t 1 , Bat tel le Pacific Northwest Laboratories, Richland, WA, January 1977.

A comparison of mixer s e t t l e r and pulse columns from a standpoint of operabi l i ty and maintenance i s given. A comprehensive table compar- ing the contactors i s included.

60. Holmes, J . H . and A. C . Schafer, "Some Operating Characteristics of the Pump-Mix Mixer Se t t le r . " Chem. Eng. Progr., z:201-204, May 1956.

Design principles of a 16-stage mixer-settler a re br ief ly described and some of i t s operating charac ter i s i t ics a re presented. I t was found tha t t ransfer efficiency was a function of both rotor speed and direction of t ransfer .

61. Jacobson, F. M. and G . H . Beyer, "Operating Characteristics of a Centrifugal Extractor. " AIChEJ, - 2:283-289, September 1956.

An i n depth examination of the operating character is t ics of a Podbielniak model 500 "Pup" extractor i s given. Variables studied were density difference, rotor speed, l ight-l iquid-out pressure, flow ra tes , holdup and number of stages. A holdup determination technique i s descri bed.

Tests were conducted on d i f fe rent packing materials fo r a solvent extraction column. The resu l t s a re correlated by an equation.

63. Jansen, G . and G. L . Richardson, Purex Pulse Column Studies-1960. HW-68846, February 22, 1961 . Many pulse column cartridges having varying plate spacing and f ree area as well as some having discrete packed sections were tested.

64. Jasny, G. R . , e t a l . , The Design, Construction, and Operation of a Pulse Column fo r the Purification of Zirconium, KT-69, Massachusetts Ins t i tu t e of Tech., Oak Ridge, TN, May 3, 1950.

A 1.5-in. diameter pulse column was bui l t and tested for removal of hafnium from zirconium. The 9.5 f t column was equivalent to s ix mixer-settler stages and had an HETS of 2.5 f t .

65. Jealous, A. C. and H . F. Johnson, "Power Requirements for Pulse Generation in Pulse Columns." Ind. Eng. Chem., 47:1159, 1955. - A n empirical correlation i s developed to determine the power i n p u t t o a pulse generator. Actual data i s compared to the resul ts obtained from the theoretical equation.

66. Jealous, A. C. and E. Lieberman, "The Concatenated Pulse Column." Chem. Eng. Progr., - 52 (9): 366-370, September 1956.

A detailed description of a concatenated pulse column and a comparison of concatenated versus t a l l columns i s given.

67. Jealous, A. C . and E. C. Stewart, A Review of the Relative Merits of Packed Columns, Pulse Columns, Mixer-Settler Mechanism, and Centrifugal Contactors. CF-51-1-10, Oak Ridge National Laboratory, Oak Ridge, TN, January 8 , 1951.

An indepth comparison of contactors was made for the f i r s t cycle in the Purex Process. Contactor operation, maintenance and design considerations were investigated. Columns appeared favorable in many categories, b u t mixer s e t t l e r s and centrifugal contactors were favored in others. No c lear cut choice i s indicated.

68. Johnson, A. I . and E. A . L . Levergue, "Holdup in Liquid-Liquid Extrac- t ion Columns." Can. J . Chem. Engr . , - 39:3741, 1961.

A theoretical approach to holdup below flooding i s proposed, b u t in practice an empirical equation must be used. Data on packed columns using the proposed correlations are presented.

69. Joseph, C . J . , e t a l . , "Technological Experience wi th Ex t r ac t i on Equipment a t Eurochemic." Proceedings of t h e I n t e r n a t i o n a l So lven t Ex t r ac t i on Conference, Vol. I and 11. S o c i e t y o f Chemical I n d u s t ~ y , London, England, 1971 . The Eurochemic process and equipment i s descr ibed . Data from f o u r y e a r s of ope ra t i on i s presen ted wi th t h e e f f e c t s o f o p e r a t i n g and des ign v a r i a b l e changes over t h a t per iod.

70. Kishbaugh, A . A . , Perfomlance of a Mult i -Stage Cen t r i fuga l Contac tor . DP-841, E . I . du Pont de Nemours & Co., I nc . , October 1963.

The c a p a c i t y and mass t r a n s f e r ob ta ined i n a 5-s tage bank of 10-in. c e n t r i f u g a l c o n t a c t o r s having a r o t o r speed of 1745 rpm i s desc r ibed . Eighty-nine t o 94% s t a g e e f f i c i e n c y with uranium l o s s e s of 0.0008% was ob t a ined when t h e u n i t was t e s t e d f o r e s t r a c t i o n and s t r i p p i n g e f f i c i e n c y .

71. K l i t gua rd , J . and J . H. Goode, Evaluat ion of Small Modified Cen Mixer- S e t t l e r s f o r t h e Ex t r ac t i on of Uranium and Thorium i n a Hot Cel l F a c i l i t y . ORNL-TM-1256, Oak Ridge National Laboratory, Oak Ridge, TN, August 30, 1965.

Experiments were made i n a modified min i -mixe r - se t t l e r on Purex and Thorex s imula ted f eeds . S t age e f f i c i e n c i e s of 65 and 77% f o r the e x t r a c t i o n and s t r i p p i n g s e c t i o n s were ob ta ined wi th uranium l o s s e s o f 0.007% i n t h e Purex runs. Uranium l o s s e s f o r t h e Thorex process were 0.19%.

72. Koski , 0 . H . , Invent ion Descr ipt ion-Devises f o r Improving t h e E f f i - c i ency of Sepa ra t i on i n Pulsed Liquid-Liquid Ex t r ac t i on Columns. HW-39938, General E l e c t r i c Co. Hanford Atomic Products Operat ion Richland, WA, November 15, 1955.

The effects of packing i n t e r p l a t e spaces i n a pu l se column a r e d i s cus sed . The packing causes a r e v e r s a l o f t h e cont inuous phase w i th in t h e o rgan ic phase wet ted packing which effects many o f the o p e r a t i n g v a r i a b l e s .

73. Ludlow, 0. J . , A New Approach t o Concatenation of Pulsed Columns. HW-38667, Hanford Atomic Products Opera t ions , Rich1 and, WA, August 16, 1955.

A conca tena ted column i s descr ibed i n which one pu l se g e n e r a t o r p rovides f low f o r t h e o rgan ic phase and puls ing f o r the e n t i r e b a t t e r y .

74. McAl l i s te r , R . A . and A. D . Ryon, A Review of Pulse-Column Flooding Data and C o r r e l a t i o n s wi th Proposed Methods of C o r r e l a t i o n , ORNL-TM-634 Oak Ridge National Laboratory, Oak Ridge, TN, June 6 , 1963.

Progress i s r epo r t ed i n assembling avai 1 a b l e f 1 oodi ng d a t a i n pe r fo ra t ed p l a t e pulsed e x t r a c t i o n columns. Exi s t i n g c o r r e l a t i o n s were c r i t i ca1 l y reviewed and r ec - ommendations f o r developing a b e t t e r c o r r e l a t i o n a r e given .

75. McCarthy, P. B . , Purex Pulse Generator Operat ion. HW-36836, General E l e c t r i c Co., Hanford Atomic Products O ~ e r a t i o n . Richland. WA, - -

May 11 , 1955;

The causes and e f f e c t s of leakage p a s t t h e p u l s e r p i s ton a r e determined. A i r p r e s s u r e behind t h e p i s t o n was found t o s t o p t h e leakage.

76. McNamee, R . J . , Re l a t i onsh ip Between Holdup and Flooding i n a Pulsed , S ieve P l a t e Ex t r ac t i on Column. ORNL-TM-1229, Oak Ridge National Laboratory, Oak Ridge, TN, p. 110, March 1968.

A method f o r determining t h e f looding r a t e based on d ispersed phase holdup a s a func t ion o f throughput r a t e and time i s presented. Holdup was determined t o be nea r ly a l i n e a r func t ion of throughput .

77. Mishra, J . C . and D. K. D u t t , "Engineering Study of Hold-up i n a Per fora ted P l a t e Pulse Column f o r t h e Countercur ren t Flow of Two Immiscible Liquids . " Chem. Age I n d i a , - 20(10) :845-852, 1969.

The e f f e c t s of pu l se v e l o c i t y , d i spe r sed and continuous-phase flow r a t e , hold d iameter , pe rcen t f r e e a r e a and p l a t e spacing on holdup were i nves t i ga ted and a c o r r e l a t i o n obta ined .

78. Morgenthal ter , J . H. , e t a1 . , Operat ing C h a r a c t e r i s t i c s of a Podielniak Cent r i fuga l Ex t r ac to r . TID-5463, Massachusetts I n s t . of Tech., Oak Ridge, TN, August 25, 1951 . The e f f e c t o f r o t o r speed, t o t a l f low r a t e , and holdup i n t h e r o t o r was s t u d i e d i n a Podbielniak "Pup" e x t r a c t o r .

79. Mottel , W. S. , Mixer-Se t t le r Devel opment--Use o f Shrouded Paddle. DP-130, E . I . du Pont de Nemours & Co., I nc . , August 1955.

The e f f e c t s o f paddle des ign and speed on t h e performance of a shrouded-paddle c o n t a c t o r a r e d i scussed . E f f i c i ency was measured by hea t t r a n s f e r between t h e phases.

80. Mottel , W . J . and T. J . Colven, Mixing E f f i c i e n c y i n Mixer -Se t t le rs - - The Effect o f Flow and Paddle Var i ab l e s . DP-254, E. I . du Pont de Nemours & Co., I n c . , December 1957.

The t r a n s f e r of hea t was used a s a measure o f the mixing e f f i c i e n c y o f a 1 - in . shrouded paddle i n a mixer se t t ler . The e f f e c t of paddle speed , t o t a l f low, f low r a t i o and mixer c o n f i g u r a t i o n on mixing e f f i c i e n c y were measured on more than 100 runs .

81 . Nichol son , G . A. , Purex Pulse Column S tud ie s w i t h Hydrocarbon D i l u e n t . HW-40550, - 2:109, J u l y 24, 1956.

The s o l v e n t e x t r a c t i o n s t u d i e s which provided the b a s i s f o r the des ign o f Hanford Purex p l a n t a r e presen ted . S p e c i f i c a t i o n s f o r a 16 ton U/day s o l v e n t e x t r a c t i o n p l a n t , and the e f f e c t s of ope ra t i ng and d e s i gn v a r i a b l e s a r e i ncl uded.

82. Nicholson, G . A. , Purex Pu l se Column S tud ie s wi th Hydrocarbon Di luen t . HW-40550, - 1 :79, J u l y 24, 1956.

The s o l v e n t e x t r a c t i o n s t u d i e s which provided t h e b a s i s f o r t h e des ign o f Hanford Purex p l a n t a r e presen ted . S p e c i f i c a t i o n s f o r a 16 ton U/day s o l v e n t e x t r a c t i o n p l a n t , and t h e effects o f ope ra t i ng and des ign v a r i a b l e s a r e inc luded .

83. Oldshue, J . Y., "Mixing Equipment i n Liquid-Liquid Ex t r ac t i on . " So lven t Ex t r . Rev. 1 , - 2:185-213, 1971.

An e x t r a c t i o n column i s de sc r ibed t h a t i s compartmented by ho r i zon ta l p l a t e s , a g i t a t e d by mixing impe l l e r s on a v e r t i c a l s h a f t and b a f f l e d by v e r t i c a l members. The e f f e c t s o f opera- t i ng v a r i a b l e s were determi ned.

84. Redon, A . , e t a1 . , Considera t ions on t h e Determinat ion of t h e Dai ly Ex t r ac t i on Capac i ty and the Working Capaci ty of the Columns o of the Eurochemic P l a n t . NP-7682, European Company f o r t h e Chemical Process ing o f I r r a d i a t e d Fuels , Mol , Belgi urn, January 9 , 1959.

The d a i l y e x t r a c t i o n c a p a c i t y and working c a p a c i t y of t h e Eurochemic columns a r e examined. I t i s concluded t h a t i t is d e s i r a b l e t o des ign e x t r a c t i o n columns t o f u n c t i o n a t 50% of the f lood ing c a p a c i t y f o r na tu ra l uranium and a t 80% f o r s l i g h t l y enr iched ma te r i a l .

85. Richardson, G. L . , Purex 1BX-IBS Column S t u d i e s , HW-84473, October 12 , 1964.

A niixed p l a t e c a r t r i d g e con ta in ing 2-i n. spaced s t a i nl e s s s t e e l nozz le p l a t e s w i t h f l uo ro thene s i e v e p l a t e s i n s e r t e d a t 8- t o 12- in . i n t e r v a l s was demonstrated i n a Hanford IBX column under both Purex

and Thorex f low cond i t i ons . The new c a r t r i d g e had much h igher c a p a c i t y and lower HTU va lues .

86. Richardson, G. L. and G . Sege, Purex Process Pulse Column S tud ie s With CC14 a s Diluent . HW-27171, September 7, 1954.

Development of t e n t a t i v e s p e c i f i c a t i o n s f o r a Purex pu l se column b a t t e r y capable o f processing 10 s h o r t t ons o f thorium per day w i t h a s o l v e n t con ta in ing 30 vol% TBP i n ~ ~ 1 4 i s presented. Tes t s were c a r r i e d o u t t o determine t h e optimum ope ra t i ng and design cond i t i ons .

87. Richardson, G . L. and A. M. P l a t t , "The Design and Operation of I n d u s t r i a l S c a l e Pu l se Columns f o r Purex Serv ice ." Progress i n Nuclear Energy, S e r i e s IV Technology, Engineering and S a f e t y , HW-SA-2037, Pergamon Press, New York, N Y , - 4:279-307, 1961.

The e f f e c t s of s i e v e p l a t e geometry, pu l se power, HTU and back mixing a r e d i scussed . The e f f e c t s of Mistron ( a f i n e t a l c ) on coa l e sc ing i s a l s o mentioned.

88. Richardson, G. L . , "Purex Pulse Column S t u d i e s wi th Zirf lex-Derived Feeds" J u l y 10, 1967, Solvent Ext rac t ion Equipment Eva1 ua t ion Study. BNWL-2186; P t 1 , B a t t e l l e P a c i f i c Northwest Labora to r i e s , Richland, WAY January 1977.

A pu l se column b a t t e r y c o n s i s t i n g of a 21 - f t high e x t r a c t i o n column, an 1 8 - f t high sc rub column and a 1 5 - f t high s t r i p p i n g column was t e s t e d .

89. Rouyer, H . 9 e t a l . , "Proceedings I n t e r n a t i o n a l Solvent Ext rac t ion conference. " ISEC174, proceedings of t h e Soc i e ty of Chemical Indus t ry . CEA-CONF-2907, London, 3:2339, 1974.

Pul sed column hydraul i c s and e f f e c t s of ope ra t i ng va r i ab l es on column e f f i c i e n c y i s given along w i t h a comparative equipment c o s t e s t ima te .

90. Rowden, G. A m , e t a l . , "Proceedings I n t e r n a t i o n a l Solvent Ext rac t ion Conference." ISEC174, 1:81, Proceedings of t h e Soc i e ty of Chemical Indus t ry , London, ~ n g l aFd, 1974.

The e f f e c t s o f changes i n t h e ope ra t i ng organic/aqueous r a t i o under both o rgan ic and aqueous cont inuous mixer cond i t i ons were s tud i ed a t l a b o r a t o r y s c a l e . I t was found t h a t t h e r a t i o s i g n i f i - c a n t l y i n f luences parameters such a s s p e c i f i c f l ow/d i spe r s ion , mass t r a n s f e r e f f i c i e n c y , and entrainment values .

91. Royston, D . and A. Burwell, Design and Performance of Pump-Mix and Gravity-Flow Mixer-Settlers. AAEC/E-274, Australian Atomic Energy Commission Research Establ ishment, Lucas Heights , New South Wales , Australia, Apr i 1 1973.

The his tor ical development of pump-mix and gravi ty f 1 ow mixer- s e t t l e r s i s reviewed. Operating design features , including scale-up are discussed. Experiments on two units are docu- mented and i t i s determined tha t increased port s i ze will increase throughput.

92. Rubin , B. and H. R . Lehman, Performance of Liquid-Liquid Extraction Equip- ment. UCRL-718, University of California, Radiation Lab., Berkeley, CA. , May 24, 1950.

Effects of design and operating variables on column efficiency i s given with an equation correlating HTU values to flow through the column, slope of the equilibrium curve and several constants.

93. Russel 1 , S. H. , Pulse Amp1 i tude and Frequency Effects i n a Pulsed Packed Column. CEI-69, Atomic Energy of Canada Ltd., Chalk River Project, Chalk River, Ontario, Apri 1 1954.

The ef fec ts on pulse column efficiency and capacity of applying pulses of varying amplitude and frequency were studied. Data from experiments a re included.

94. Ryon , A . D . , e t a1 . , Experimental Basis fo r the Design of Mixer-Settl e r s

A 6-in. diameter mixer i n a barrel was used to determine the effectiveness of the extraction of uranium from solution by a long chain amine. Greater than 90% stage efficiency was obtained .

95. Schlea, C . S . , e t a l . , Purex Process Performance w i t h Short-Residence Contactors. DP-809, E . I . du Pont de Nemours & Co., Inc., September 1963.

The operation of a 16-stage centrifugal contactor i s described. Decontamination factors of 104 were achieved for zirconium-niobium and ruthenium. The ef fec ts of i r rad ia t ion 1 eve1 of the fuel , operating temperature, sol vent saturat ion, nitrous acid, ferrous sulfamate versus U(IV) as a reductant fo r Pu(1V) on decontamination, and plutonium part i t ioning are discussed.

96. Sege, G . and F. W . Woodfield, Pulse Column Variables - Solvent Extraction of Uranyl Nitrate w i t h ~ r i b u t y u Column. HW-27365, April 20, 1953.

General performance character is t ics of a pulsed column are discussed. The ef fec ts of operating conditions and sieve plate section design on column efficiency are descri bed. The application of t e s t s in a 3-in. diameter column t o larger columns i s discussed.

97. Sehmel , A: and A . L. Babb, "Holdup Studies in a Pulsed-Sieve Plate Column." Ind. & Eng. Chem. Process Desiqn, - 2:38-42, June 1963.

The effects of pulse amplitude, phase flow ra t e s , and pulsation frequency on dispersed phase holdup were studied i n a 2-in. di ameter pul se col umn.

98. Sehmel, G . A . and A. L . Babb, "Longitudinal Mixing Studies in a Pulsed Extraction Column." Ind. & - ~ n g . Chem. process Design, 3:210-214, July 1964. - Longitudinal mixing of the continuous phase a t several pulse frequencies was measured. Two mathematical models were derived t o predict the extent of longitudinal mixing. Experiments agreed with the predictions to within 10%.

99. Seyfr i t , K . V . , Purex 2A Column Capacity Studies. HW-51757, General Electric Co. , Hanford Atomic Products Operation, Richland, WAY July

Cold t e s t s were run in a 6-in. diameter packed pulse column to simulate the Hanford Purex process 2A column using the Purex Process Phase I1 flowsheet.

100. Sleicher, C . A . , J r . , "Entrainment and Extraction Efficiency of Mixer Se t t le rs . I 1 AIChEJ , - 6: 529-530, September 1960.

An analytical method fo r determining extraction efficiency in a multistage mixer-settler i s developed. The equations can be used t o design mixer-settlers and indicate tha t many mixer-settlers are overdesi gned. Resul ts show t h a t high entrainment rates have 1 i t t l e e f fec t on mixer-settler efficiency.

101. Smoot, L . D . , e t a1 . , "Flooding Characteristics and Separation Efficiencies of Pulsed Sieve Plate Extraction Columns. " Ind. Eng. Chem., 51:1005-1010, 1959. - Data from 751 pulse column flooding experiments using a wide range of systems was. compi led and correlated. Nomographs re1 a t i ng the operating and design variables are included.

102. Sobotik, R . H. and D . M. Himmelblau, "Effect of Plate Netting Characteristics of Pulse Col umn Extraction Efficiency. " AIChEJ, 6 : 61 9-624, December 1960. (ISC-900) -

Studies were carried out i n a 3-i n . diameter pulse column w i t h s t a in l e s s s tee l plates spaced 1 .5-in. apart w i t h 0.125-in. hole diameters and 18.7% f r e e area. HTU values were related t o operating variables.

103. Spaay, N . M. , e t a1 . , "Proceedings International Solvent Extraction Conference." ISEC171 , - 1 :281, Proceedings of the Society of Chemical Industry, London, 1974.

Data from 2-, 4- and 9-in. column t e s t s a re presented t o demonstrate tha t drop diameter, hold-up of dispersed phase, axial mixing and mass t ransfer in a pulsed packed column are of essential importance to extraction efficiency.

104. Srinivasan, N . , e t a1 , Development of Air Pulsed Mixer Se t t l e r Equipments fo r Solvent Extraction Studies. BARC-672, Bhabha Atomic Research Centre, Bombay, India, 1973.

A small glass air-pulsed mixer s e t t l e r i s described. Tests with pulse frequencies of 80 and 110 cycles/sec and ampli tudes of 7-and 12-in. resulted i n stage eff ic iencies to 90 to 100%.

105. Stevenson, R . L . and J . G. Bradley, TBP Plant Solvent-Extraction Pulse Col umns. HW-19170, General Electr ic Co. , Rich1 and, WA, November 6 , 1951 . Sol vent extraction studies 1 eadi ng to the development of pul se column specifications for TBP Waste Metal Recovery Plant a t Hanford are included a1 ong w i t h a tab1 e showing the e f fec ts of operating and design variables.

106. Swift, W . H., Back-Mixing in Pulse Columns w i t h Particular Reference to Scale-up. HW-28867, July 20, 1953.

Coalescence in pulse columns was studied by introducing colored drops into the organic and aqueous phase respectively. I t was determi ned t h a t no backmi xi ng occurred i n the organi c (di spersed ) phase b u t considerable backmixing occurred in the aqueous (continuous) phase.

107. Swift, W. H . and L. L . Burger, Backmixing In Pulse Columns, 11. Experi- mental Values and Effect of Several Variables. HW-29010, Hanford Atomic Products Operation, August 11 , 1953.

An in-depth discussion of the causes and ef fec ts of backmixing i n pulse columns i s given. The e f fec t of operation and design variables on backmixing i s also discussed.

108. Swi f t , W . H . , Limit ing Flow Capaci ty i n So lven t Ext rac t ion Pulsed Columns. P a r t 1: The E f f e c t of Pulse and Ca r t r i dge Geomety Var iab le . HW-33953, Hanford Atomic Products Operat ion, November, 30, 1954.

A p re l iminary c o r r e l a t i on o f the e f f e c t of c a r t r i d g e geometry, pu l se , and volume f low r a t i o v a r i a b l e s i s developed, f o r s i e v e p l a t e pu l se columns i n t h e reg ion of emulsion type f l ood ing wi th a noncoalescing system wi thout a d i s t r i b u t e d s o l u t e . The c o r r e l a t i o n agreed wi th experimental d a t a t o w i t h i n 10% on 180 runs.

109. T h e i l e , E. W . , "Absorption and Ex t r ac t i on . " Ind. Eng. Chem., p. 1021 , June 1960.

Film type e x t r a c t o r s , sp ray towers , b a f f l e towers , pe r fo ra t ed p l a t e towers , packed towers and mixer s e t t l e r s a r e desc r ibed . No d i r e c t compari sons under s imi 1 a r ope ra t i ng condi t i o n s a r e given.

110. Thorton, J . D . , "Mechanical Contactors f o r Liquid-Liquid Ext rac t ion ." Nuclear Eng., 1:156-160, 1956.

A comparison of 25 c o n t a c t o r types i s given. The more important t ype c o n t a c t o r s f o r r a d i o a c t i v e use were determined t o be pulsed and r o t a r y columns and KAPL-type mixer s e t t l e r s .

11 1 . Thorton, J . D . , "Liquid-Liquid Ex t r ac t i on . P a r t XIII : The Effect of Pulsed Wave Form and P l a t e Geometry on t h e Performance and Throughput of a Pulsed Column." Trans. I n s t . Chem. Eng., 35-:316-330, 1957.

Experiments were conducted i n a 3-i n. d iameter column wi t h varying p l a t e spac ings and f r e e a r ea s t o determine t h e effect of pu l se wave shape on column ope ra t i on .

112. Thornton, J . D . , "Recent Developments i n Pulsed-Column Techniques." Chem. Eng. Progr . Symp Ser. 50, - 13:39-52, 1954.

An overview of t h e progress i n pu l se column technology, a f looding co r r e l a t i on, and appa ren t e f f e c t s of o p e r a t i ng v a r i a b l e s i s given.

113. Todd, D. B and W. J . Podbie ln iak , "Advances i n Cent r i fuga l Ex t r ac t i on . " Chem. Eng. Progr . , - 61:69-73, May 1965.

An overview o f t h e c h a r a c t e r i s t i c s of Lu Westa, De Lava1 and Podbielniak con tac to r s i s presen ted . Capac i t i e s va r i ed from 0.06 t o 600 gal/min and d iameters from 16 t o 60 i n . were compared.

11 4. Todd, D . B. , "Improving Performance of Centrifugal Extractors. " Chem. Eng. Progr., s : 1 5 2 , July 24, 1972.

General characteri s t i cs of centrifugal contactors a re descri bed. An equation i s developed to predict the i n i t i a l pressure requirements. I t i s suggested tha t the major phase should be dispersed in to the minor phase.

11 5. Treybal , R. E . , "Liquid Extracti on Techniques and Practi ce. " Ind. Eng. Chem, - 54:55-60, 62-63, 1962.

A general ized treatment of several contacting devi ces including pulse columns i s presented. No concl usi ons regarding the re la t ive merits of the contactor i s given.

11 6. Treybal , R . E . , "Economic Design of Mixer-Settl e r Extractors. " AIChEJ, - 5~474-482, 1959.

Equations are developed for establishing the most economic values of the major variables of a l iquid extraction process, including solute i n recycled sol vent and rejected ra f ina te , the solvent to feed r a t io , and some of the design features of mixer s e t t l e r s .

117. Treybal, R . E . 9 "Liquid Extractor Performance." Chem. Eng. Progr., 62(a):67, 1966. -

A comparison of mixer s e t t l e r s , packed towers and perforated plate towers was made. Backmixing was found to be a problem only i n the packed towers.

118. Troutman, P. H. and J . A. Consiglio, Simulation of a Solvent Extraction Pulsed Column. TID-12472, General Electr ic Co. , General Engineering Laboratory, Schenectady , NY, October 1 , 1958.

Preliminary data on pulsed columns i s reviewed and an analog computer model was developed f o r simulating the steady-state operation of a pulsed column. Due to the low degree of accuracy of the data correlation the model was never tested.

119. Vermeulen, T . and D . R . Kahn, Jet-Mixed Liquid-Liquid Extraction Column. U.S. Patent 3,574,558, U.S. Patent Office, Washington, D C , April

A column ut i l iz ing uniformly spaced, horizontal tubular j e t t i ngs and intake, rings a t the center and periphery of several cross sections i s descri bed.

120. Vermeulen, T. , e t a1 . , "Axial Dispers ion i n Ex t r ac t i on Columns. " Chem. Eng. Progr . , - 6:95-102, September 1966.

The in f luence o f a x i a l d i s p e r s i o n on t h e s e p a r a t i n g e f f i c i e n c y o f a v a r i e t y o f columnar c o n t a c t o r s was s t u d i e d . The experimental d a t a and c o r r e l a t i o n made by a number of i n v e s t i g a t o r s i s compiled and compared.

121. Warner, B . F . , e t a l . , A Review of t h e S u i t a b i l i t y o f Solvent Ext rac t ion f o r t h e Reprocessing o f F a s t Reactor Fuels . BNWL 178(W).

I r r a d i a t i o n tests on TBP were made and i t was concluded t h a t t h e long r e s idence t ime i n mixer settlers p roh ib i t ed t h e i r use w i t h i r r a d i a t e d f u e l .

122. Warwick, G. C . I . , e t a1 . , "Proceedings I n t e r n a t i o n a l Solvent Ex t r ac t i on Conference." ISEC'71, - 2: 1373, ~ o c i e t y of Chemical Indus t ry , London, England, 1971 . A convent ional mixer se t t le r uni t was t e s t e d t o detemi ne i ts e f f e c t i v e n e s s i n recover ing copper. Ex t r ac t i on and s t r i p p i n g ef f i ci enci e s of 95% were r epo r t ed .

123. Webb, R. P. , e t a1 . , Appl i ca t i on of Pulse Column t o Recovery of Uranium i n Waste So lu t ions . KT-79. Massachusetts I n s t . of Tech.. Oak Ridae. TN.

The use of a 1 5 - f t high by 1.25-in. d iameter column f o r recovery of uranium from waste s o l u t i o n s i s d iscussed . HETS va lues ranged from 5.5 t o 12.5 f t uranium concen t r a t i on i n waste was a s low a s 0.05 ppm.

124. Webster, D . S . , e t a l . , Performance of Cent r i fuga l Mixer -Se t t le r i n Reprocessing Nuclear Fuel . E. I . du Pont de Nemours & Co., Inc . , Aiken, SC.

An 18-stage c e n t r i f u g a l con tac to r t h a t had been i n use f o r 1 y e a r i s desc r ibed . The advantages of the s h o r t r e s idence time c o n t a c t o r a r e d i s cus sed . Data from t h e ope ra t i on of the c o n t a c t o r i s presen ted and d i scus sed .

125. Webster, D . S . , Mixer S e t t l e r Development--Characteristics of the Pump-Mix Impel le r . DP-137, E . I . du Pont de Nemours & Co., Inc . , October 1955.

A s t udy of t h e hyd rau l i c s of m i x e r - s e t t l e r impe l l e r s was conducted. I t was found t h a t the impe l l e r behaved l i k e a low-head pump and was n o t a f f e c t e d by r e c i r c u l a t i o n from the mixing t o the s u c t i o n s e c t i o n s .

126. Webster, D. S., e t a l . , Hyd rau l i c Performance of a 5-Inch C e n t r i f u g a l Con- t a c t o r . DP-370. E. I. du Pont de Nemours & Co., Inc., August 1962.

A 5- in. c e n t r i f u g a l con tac to r f o r so l ven t e x t r a c t i o n was operated t o determine t h e capac i t y and e f f i c i e n c y as a f u n c t i o n o f bowl speed, w e i r pos i t i ons , a i r entra inment and f l o w r a t i o s .

127. Webster, W. B., "Minutes o f Meeting--RDA No. DC-4 Working Committee, February 1952." So lvent E x t r a c t i o n Equipment Eva lua t i on Study. BNWL-2186; P t 1, B a t t e l l e P a c i f i c Northwest Laborator ies, Richland, WAY January 1977.

A comparison o f con tac to r types i s g iven i n which i t i s s t a t e d t h a t m i x e r - s e t t l e r s a r e slower t o recover from opera t i ng upsets and t h a t c r i t i c a l i t y problems cou ld a r i s e i n mixer s e t t l e r s . Tests a r e necessary before a mixer s e t t l e r system can be s p e c i f i e d f o r any g iven process and work space.

128. Whatley, M. E., Mu1 t i s t a g e M ixe r -Se t t l e r Arrangement f o r L i q u i d - L i q u i d Ex t rac- t i o n . U.S. Patent 2,754,179, U.S. Patent O f f i c e , Washington, DC, J u l y 10, 1956.

A m ixe r s e t t l e r having a unique i n te rconnec t i on o f m i x i n g and s e t t l i n g chambers by means o f w i e r tubes i s descr ibed b u t no data i s given.

129. Woodfield, F. W. and G. Sege, "A Louver-Plate R e d i s t r i b u t o r f o r Large Diameter Pulse Columns." Chem. Eng. Progr. Symp. Ser., 50(13) ;14, 1954.

R e d i s t r i b u t o r p l a t e s were i n s e r t e d between the s ieve p l a t e s i n a 23.5 i n . diameter pu lse column t o prevent channel ing. This dropped t h e waste losses from 6% t o 0.001%.

8.0 LISTING OF ALL THE CITATIONS SCREENED FOR THE LITERATURE REVIEW

8.0 LISTING OF ALL THE CITATIONS SCREENED

, . FOR THE LITERATURE REVIEW

Abi t a , M . , e t a1 . , S c a l e Representat ion of Banks of Liquid-Liquid Ext rac t ion . . Processes . RT/CHI-(70)46, Comi t a t 0 Nazionale per 1 ' Energia Nucleare, Rome, I t a l y ,

November 26, 1970.

Ager, D. W . and E. R. Dement, "Solvent Ex t r ac t i on i n Me ta l l u r s i ca l Processes ." - -

Proceedings I n t e r n a t i o n a l ~ f i p o s i um, Technologic I n s t i t u t e K: VIV, Antwerp, p. 27, 1972.

Ahnoff, M. and B. Josefsson , "Simple Apparatus f o r On-si te Continuous Liquid- Liquid Ext rac t ion o f Organic Compounds from Natural Waters." Anal. Chem. 46 : 658-663, May 1974. - Akel l , R. S . , "Solvent Ext rac t ion : Ext rac t ion Equipment Avai lab le i n t h e U.S." Chem. Eng. Prog. g : 5 0 - 5 5 , September 1966.

Alders , L . , Liqui'd-Liquid Ex t r ac t i on . 2nd ed. , E l sev i e r Pub1 i s h i n g Company, Amsterdam, 1959.

Alfredson, P. G . , e t a1 . , Development of Processes f o r P i l o t P l a n t Production o f P u r i f i e d Uranyl N i t r a t e So lu t ions . (AAEC/E-344), Aus t r a l i an Atomic Energy Commission Research Establ ishment , Ph.ysics Div is ion , Lucas Heiqhts, New New South Wales, A u s t r a l i a . ~ a n u a r y 1975.

-

Almond, J . N. and P. M. J . Gray, The Ext rac t ion of Uranium from T i t a n i f e r o u s Uranium Ore, Radium H i l l , South A u s t r a l i a , P a r t VII. CS/RO/UI/14, Commonwealth S c i e n t i f i c and I n d u s t r i a l Research Organiza t ion , Divis ion of I n d u s t r i a l Chemi s t r y , November 1951.

Alter, A. W . , e t a l . , A Minia ture Mixer S e t t l e r f o r Continuous Countercurrent Solvent Ex t r ac t i on . (KAPL-961) , Knoll s Atomic Power Laboratory, Schenectady, N Y , November 25, 1953.

A l tho f f , R. F., "Iso tope-Ext rac t ion Process Copes with Radioact ive Waste." Chem. Eng. - 75:150-152, March 11, 1968.

Aly, G. S. , "Dynamic Behavior of Mixer S e t t l e r s . " ISECt74, - 1:189.

Andersson, C. , e t a1 . , "Sol vent Ex t r ac t i on S t u d i e s by the AKUFVE Method. I1 I . Experimental Technique f o r Equi l ibr ium S t u d i e s Using Radioact ive Tracers . " Acta, Chem. Scand. , - 23(8) : 2781 -2796, 1969.

Angelino, H. and J . Moliner, "Study o f Back Mixing E f f e c t i n a Pulsed Rota t ing Disc Contactor ." ISEC171, - 1 :688.

Angelo, J . B . , "L igh t foo t , E . N . , Mass T rans fe r Across Mobile I n t e r f a c e s . " AIChEJ , - 14: 531-540, J u l y 1968.

Anwar, M. M . , e t a l . , "A Continuous, Bench-Scale, Mul t i s tage , Countercur ren t , Liquid-Liquid Contactor . " Chem. Ind. p. 1090, 1969.

Arnold, D. S., et al., "Metal Refining by Solvent Extraction of Leach Slurries." Chem. Eng. Prog. - 54:90-95, October 1958.

Arnold, D. Ray et al., "Droplet Size Distribution and Interfacial Area in Agitated Contactors." ISEC174, p 1619.

Ashton, N., et al., "Proceedings International Solvent Extraction Conference." ISEC'74, - 2:1813, Proceedings of the Society of Chemical Industry. London, 1974.

Astarita, G. "Experiments on Liquid-Liquid Extraction in a Spray Column." Chim. e ind. - 43:lO-16, 1961.

Atwoody J. M. and 0. H. Koski, Automatic Control of a Pulsed Column Battery. HW-SA-3237, Northwest Regional Meeting of AIChE, Portland, OR. October 10, 1963. . Auchapt, P., et al., "Applications of Solvent Extraction to Concentration and Purification of Plutonium. I. Marcoule: Utilization of Tributyl Phosphate." Energ. Nucl . - 10: 181 -186, May 1968.

Ayers, A. L. and F. M. Warzel, "Comparison of Design and Operating Performance at the I.C.P.P." Chem. Eng. Progr., 56-:1-11, Symposium Series No. 28, 1960.

Babb, A. L., et al., Dynamics of Solvent Extraction Systems. 111. Progress Report No. 3, October 1969-September 30, 1970. RLO-2225-7-11-1, Washington University , Department of Nuclear Engineering, Seattle, WA. October 1970.

Babb, A. L., Separation Efficiency of Solvent Extraction Systems. Progress Re~ort No. 10. October 1. 1965-Se~tember 30. 1966. RLO-1053-3. Washinaton ~niversi ty, ~e~artment of ~uclear' ~ n ~ i n e e r i n ~ , Seattle, WA. 0;tober 1; 1966.

Bailes, P. J., et al., "Liquid-Liquid Extraction: The Process, the Equipment." Chem. Eng. - 83:86-100, January 19, 1976.

Baillie, M. G. and R. C. Cairns, Development of a Ten-Stage Mixer Settler for $35 Solutions. Part I. AAECIE-40, Atomic Energy Commission Research Establishment, Lucas Heights, New South Wales, Australia, November 1958.

B$Qlie, M. G. and R. C. Cairns, Development of a Ten-Stage Mixer-Settler for U Solutions Part 11. AAECIE-56, Atomic Energy Commission Research Establishment, Lucas Heights, New South Wales, Australia, December 1960.

Baillie, M. G. Pulse Columns in Nuclear Fuel Reprocessing. Part 1. Literature Survey. AAECIE-50, Atomic Energy Commission Research Establishment, Lucas Heights, New South Wales, Australia, May 1959.

- . Baird, M. H. I. and G. M. Ritcey, "Proceedings International Solvent Extraction Conference." ISEC174, - 2:1571, Proceedings of the Society of Chemical Industry, London, 1974.

Baird, M . H. I . , e t a1 . , "Solvent Ext rac t ion i n an Air-Pulsed Packed Column." Can. J . Chem. Eng., g :249 -252 , August 1968.

. - Baird, M. H. I . , e t a l . , "Flooding Condit ions i n a Reciprocat ing P l a t e Extrac- t i o n Column." ISEC'71, - 1 :251.

Balasubramanian, G. R. and N. Sr invasan, P i l o t P l a n t S t u d i e s wi th Mixer S e t t l e r s . BARC/I-253, Bhabha Atomic Research Centre , Bombay, Ind i a , 1973.

Bal l a r d , J . H. L i m i t i n g Flow Phenomena i n Packed Liquid-Liquid Ex t r ac t i on Columns. Thes i s , Un ive r s i t y o f Minnesota, Minneapolis, M N y August 1949.

Barame, S., e t a l . , " In f luence d 'une Ag i t a t i on Ro ta t i ve Sur l e Me'lange En Rotour Dans Une Colonne Pulsee a P la teaux Pe r to re s . " Can. J . Chem. Eng., 51:156-161, Apr i l 1973. - Barnea, E. and J . Mizarhi , Trans. I n t . Chem. Engr., - 53:61, 70, 75 and 83, 1975.

Barson, N . and G. H . Beyer, " C h a r a c t e r i s t i c s o f a Padbielniak Cent r i fuga l Ext rac tor . " Chem. Eng. Proq., fi:243, 1953.

Becker, K. W . , "Solvent Ext rac t ion Engineering and Design." Am. Oil Chem. Soc. J . , 4 1 ( 8 ) , October 1964.

Behmoiras, J . , e t a l . . "Performance of Pulsed S ieve-Pla te Ext rac t ion Columns During t h e s e p a r a t i o n - o f Uranium from Thorium. " Ind. Eng. Chem., Process Design Develop., L ( 1 ) : 64-68, January 1962.

Belaga, M. W. and J . E . Bigelow, E f f e c t of Pulse Column Operating Var iab les on H.T.U. (KT-133; EPS-K-181) , Thes is , Massachusetts I n s t . o f Tech. Engineering P r a c t i c e School, Oak Ridge, TN, January 11, 1952.

B e l l , R . L . and A. L. Babb, "Holdup and Axial D i s t r i b u t i o n of Holdup i n a Pulsed Sieve-Pl a t e So lven t ~ x t r a c t i o n Column. " I&EC Process Design and Develop., g ( 3 ) : 392-400, J u l y 1969.

B e l t e r , P. H . , "Simulat ion o f F rac t iona l Liquid-Liqui-d Ext rac t ion Processes ." Ind. & Eng. Chem., - 59:14-21, March 1967.

Bernard, C. , e t a1 . , "Experience wi th Contr i fuga l Ex t r ac to r s : Comparison w i t h Other Types o f Ex t r ac to r s . " ISEC171, 2:1282.

Berns te in , G. J a y e t a l . , Development and Performance of a High Speed, Long- Rotor Cent r i fuga l Contactor f o r Appl i c a t i on t o Reprocessing LMFBR Fuel s . ANL-7968, Argonne National Laboratory, Argonne, IL, January 1973.

Beyer, G . H. and F. M. Jacobsen, Operat ing C h a r a c t e r i s t i c s o f a Cen t r i f uga l Ex t rac to r . (ISC-548), Ames Laboratory, Ames, IA, November 26, 1954.

Bibaud, R. E. and R. E. Treybal, "Ax ia l M ix ing and E x t r a c t i o n i n a Mechanical ly Ag i ta ted L i q u i d E x t r a c t i o n Tower. " AIChEJ, - 12(3):472-477, 1966. ..

Bloom, J. L. and L. D. Christensen, "A Four-Stage Prototype M ixe r -Se t t l e r . " (LRL-52), Cal i f o r n i a Research and Development Co. Livermore Research Laboratory, Livermore, CAY Contract AT(l1-1)-74, LRL-52, September 1953.

Bochinski, J. H., Separat ion o f I n a i v i d u a l Rare Earths by L i q u i d - L i q u i d E x t r a c t i o n f rom Multicomponent Monazite Rare-Earth N i t r a t e s . Ph. D. Thesis, Iowa S t a t e College, Ames, IA, 1954.

Bo lo tn ikov , F. S. and P. G. Romankov, " L i q u i d Ex t rac t i on . I V . Mass Trans fer i n an Inc l i ned , V i b r a t i n g Ex t rac to r . " Zh. P r i k l . Khim., - 37(1):46-50, 1964.

B o r r e l l , A., e t a l . , "Con t r i bu t i on o f t he Dispersed Phase t o the Long i tud ina l M ix ing i n a Ro ta t i ng Disc Contactor. " ISEC174, - 2: 1341.

Bourns, W. T., The Design, Const ruc t ion and Operat ion of an Apparatus f o r E x t r a c t i o n o f Uranium f rom F i s s i o n Product So lu t ion . Atomic Enerav o f ~ - - - - - - - - - ~~ - - ~- 4"

Canada Ltd., Chalk R iver - p r o j e c t , Chalk River , ~ n t . , May 1953.

Bradley, J. G. and G. Sege, Report o f Invent ion : R e d i s t r i b u t o r f o r Pulsed L iqu id -L iqu id E x t r a c t i o n Columns. September 24, 1953.

Breschet, C. and P. Miquel, "Improvement of t h e Procedure Used t o T rea t H igh l y I r r a d i a t e d Fuels. (Example o f t he U t i l i s a t i o n o f Complexins and Redox Aqents i n a Sol vent ~ x t r a c t i on process. " Proceedings o f the ' ~ n t e r n a t i o n a l s o l vent E x t r a c t i o n Conference. Vol. I and 11. Soc ie ty o f Chemical I ndus t r y , London, England. 1971.

Bresse, J. C., Ore Processing: Resin Test Loop Studies--Problem Statement. CF-55-2-146, Oak Ridge Nat iona l Laboratory, Oak Ridge, TN, February 18, 1955.

Bresse, J. C. and C. V. Chester, "The Use o f Radioisotopes f o r t h e Measure- ment o f I n t e r f a c i a l Area. " I n : Proceedings o f t h e second I n t e r n a t i o n a l Conference on t h e Peaceful Uses o f Atomic Energy, Geneva, 1958. Un i ted Nations, - New York, NY, - 20:168-172, 1959.

Bril, K. J . and E. C . Costa , Technology of Pulsed S i eve -P la t e Ex t r ac t i on Columns. P a r t I . Ca r t r i dge Design. P a r t 11. I n t e r f a c e Level Control . I n s t i t u t o de Energia Atomica, Sao Paulo, Brazi 1 , November 1964.

Brown, A. H. and C . Hanson, "Drop Coalescence i n Liquid-Liquid Systems." Nature, - 21 4(5083) : 76-77, 1967.

Brown, A. H. and C. Hanson, " E f f e c t o f O s c i l l a t i n g Electric F ie ld s on t h e Coalescence of Liquid Drops." Chem. Eng. Sc i . , - 23:841, 1968.

Bruce, F. R e , e t a l . , "Operating Experience with Two Radiochemical Processing Pi l o t P l an t s . " In: proceedings o f ' t he . Second I n t e r n a t i o n a l Conference on - t h e Peaceful Uses of Atomic Energy, Geneva, 1958, United Nations, New York, N Y , - 17:49-72, 1959.

Bruns, L. E . , Recuplex S tage Height, Transfer-Unit Height, and S tage Effi- c iency Ca lcu l a t i ons . HW-22742, Hanford Works, Richland, WAY November 16 , 1951.

Bruns, L. E . , Air Pu l se r f o r H-1 Column. HW-68636, General E l e c t r i c Co. Hanford Atomic Products Operat ion, Rich1 and, WAY March 1 , 1961.

Buck, C . , e t a l . , "Chemical Process a t U.K. Atomic Energy Author i ty Works, Dounreay." In: Proceedings of the Second I n t e r n a t i o n a l Conference on t h e Peaceful Uses o f Atomic Energy, Geneva, 1958. United Nations, New York, N Y , 17: 25-45, 1959. - Burger, L . L . , e t a l . , Liquid-Liquid Dispers ions and t h e S i g n i f i c a n c e of the Disengaginu Tes t . HW-24989, Hanford Atomic Products Operat ion, Richland, WA, J u l y 10, 1952.

Burger, L. L. and L. H. Clark, The Valve-Actuated Pulse Column-11. A Study of the Temperature E f f e c t and Design Var iab les . HW-26459, Hanford Works, Richland, WAY February 16 , 1953.

Burger, L. L . and L. H. C la rk , The Valve-Actuated Pulse Column Design and Operation. HW-23141, Hanford Works, Richland, WA, December 3 , 1951.

Burger, L. L . , Effect o f Temperature on Uranium Recovery Column Operation. HW-29001, Hanford Works, Richland, WAY August 12, 1953.

Burger, L . L . , So lvent Ex t r ac to r f o r Aqueous So lu t ions of Metal S a l t s . U.S. Pa t en t 2,743,170, U.S. Pa t en t Off ice , Washington, D C , Apri l 24, 1956.

Burkart , C. A . , e t a l . , P u r i f i c a t i o n of Thorium N i t r a t e by Solvent Ext rac t ion with Tr ibu ty l Phosphate. 11. Mixer -Se t t le r P i l o t P l a n t Inves t i ga t ions . BMI-262, B a t t e l l e Menlorial I n s t i t u t e , Columbus, O H , J u l y 31, 1952.

Burkhart , L . E. and R. W. Fahien, Ex t r ac t i on E f f i c i ency of a Pulsed Column of Varied Geometry. ISC-860, Ames Laboratory, Arnes,..IA, June 1956.

Burns, W. A . , S tepwise Ca lcu l a t i on f o r t h e Determination o f t h e Number o f T r a n s f e r Units i n Countercur ren t Ex t r ac t i on Columns. HW-14445, Hanford Works, Richland, WA, September 12 , 1949.

Burns, W. A . , e t a l . , The Design and Operat ion of t h e Pulse Column. HW-14728, Hanford Works, Richland, W A Y October 12, 1949.

Busso lu r i , R . , e t a l . , "Flow o f Liquids Through Pe r fo ra t ed -P la t e Liquid Ex t r ac t i on Towers. " Ind. Eng. Chem. , - 45: 241 3-241 7, 1953.

B u t t e r s , P . A . , "Sepa ra t i on o f Tantalum and Niobium by Solvent E x t r a c t i o n . " Chem. & Ind . , pp. 613-618, Apr i l 15, 1967. . Byerlee, H. W . , "The Solvent Ex t r ac t i on o f Uranium from S l u r r i e s . " Conf- 690815-4, Mineral Bene f i c i a t i on Paper No. 5, p resen ted a t t h e Conference o f t h e A u s t r a l i a n I n s t i t u t e o f Mining and Metal lurgy, Sydney, A u s t r a l i a , Apr i l 14 , 1969.

Byersmith, R . B . , e t a l . , I ron Removal from Beryllium S o l u t i o n s by So lven t Ex t r ac t i on Methods. NY0116, Brush Beryllium Co. June 25, 1953.

Casto, M. G . , e t a l . , "Some Dynamic Cons idera t ions of a Mul t i s t age Mixer- S e t t l e r E x t r a c t o r and S t r i p p e r . " Ind. Eng. Chem. Process Design, - 12:432-437, October 1973.

Cavendish, J . H . , "Reext rac t ion o f Uranium from Tri-n-Butyl Phosphate-Kerosene Solvent . " NLCO-883, National Lead Co. of Ohio, C i n c i n n a t i , O H , August 30, 1963.

Cermak, A . , Horizontal Pu l sa t i on E x t r a c t i o n Column wi th Reduced Length. March 1970.

Cerny, J.9 Hydroclone Performance i n t h e Solvent Recovery System o f t h e Thorex P i l o t P l a n t . Oak Ridge National Laboratory, Oak Ridge, TN, March 31, 1958.

Chakloz, T. , e t a l . , "Mass T rans fe r S t u d i e s i n a Hel ica l So lven t E x t r a c t o r . " ISEC171, 2:1277.

-. - .

Chantry, W. A * , e t a l . , "Appl ica t ion o f Pu l sa t i on t o Liquid-Liquid E x t r a c t i o n . " . . Ind. & Eng. Chem., - 47:1153; June 1955.

Chazel, G. and D . Hoclet , "Hybrid Simulat ion of the Dynamics o f a Bat te ry of Mixer -Se t t le rs . " CEA-CONF-1579, Presented a t t h e Conference on Hybrid Computation, Munich, Germany, 1970.

Chazel , G . , "Simulat ion, Regulat ion, and Optimizat ion o f the Dynamics of a Mixer-Decanter Bank by a Hybrid (Analogue-Digi t a l ) Method. " Commissariat a 1 ' Energi e Atomi que, Centre d ' Etudes Nucl e a i res , Sac1 ay , France, December 1971 . Chen, B. H., "Determination of Residence-Time D i s t r i b u t i o n i n End Sec t ions o f I n t e r f a c i a l Contact ing Devices." Can. J Chem. Eng., z :420-423 , June 1974.

Chen, B. H . , "Performance o f Screen-Packed Liquid-Liquid Ext rac t ion Tower." Ind. & Eng. Chem. Process Design, January 1973.

Chien, H. H . Y . , "Optimizat ion o f Recycle Problem." Ind. & Eng. Chem. Fundamentals , 5: 66-68, February 1 966.

Chi lenskas, A . , " Induc t ive Heating and Mixing." In: Argonne National Labora- t o r y Chemical Engineering Divis ion Summary Report, Oct., Nov., Dec. 1972, ANL-6048, Argonne National Laboratory, Argonne, IL, pp. 11 3-1 15, May 1963.

Choffe, B. and Y . L. Gladel , "E f f i c i ency o f a Pe r fo ra t ed -P la t e Pulsed Column." J . Appl. Chem., 8:580-586, 1958.

C lage t t , F., Contact Anqles on Fenske Ex t r ac to r and Disengaginq Time S tud ie s of Recopl ex Process Sol u t i o n s , HW-23011, November 21 , 1951.

Clark, A. T., J r . , Performance of a 10-inch Cent r i fuqa l Contactor . DP-752, E. I . du Pont de Nemours & Co. , Inc. , Ai ken, SC, September 1962.

Claybaugh, B. E . , Limit ing Flow Capac i t i e s i n a Pulse Column. M . S. Thesis, Okl ahoma S t a t e Un ive r s i t y , S t i 1 lwa te r , OK, August 1959.

Clemons, C. W . , Liquid-Liquid Ext rac t ion Processes . TID-6424, Michigan Chemical Corp., S t . Louis, MO, August 13, 1957.

Clerk, J . , "Costs f o r Rota t ing Disk Contac tors . " Chem. Eng., f l :232, October 12, 1964.

Cloe te , F. L. D . , "A Simple Air Puls ing Technique f o r Liquid Ext rac t ion Columns." J . B r i t . Nucl. Energy Soc., - 4:296-8, October 1965.

Cohen, R. M. and G. H . Beyer, Performance of a Pulse Ex t r ac t i on Column, ISC-294, Ames Laboratory, Ames, IA, p. 43, December 1952.

Col burn, A. P . , "The Simp1 i f i e d Ca lcu l a t i on of ~ i f f u s i o n a l Processes , General Cons idera t ion o f . Two-Fi lm Res is tances . " Trans. Am. I n s t . hem. . . Engs., - 35:211-236, 1939.

L

Coleby, J . , British P a t e n t 860,880; 972,035 and 1.037,573. - .

C o l l i n s , S. B. and L. E . Burkhart , A F i n i t e Di f fe rence Model of the Pu l se Column, Ames Labora tory , Ames, IA, J u l y 1963.

Colven, T. J.9 J r . and W . J . Mot te l , Mixinq Eff ic iency i n Mixe r -Se t t l e r s . The Effec t of Flow and Paddle Var i ab l e s . DP254, E. I . du Pont d e Nemours & Co., Savannah River Laboratory, Aiken, SC, December 1957.

Colven, T. J . , J r . , Mixer -Se t t le r Development-Operating C h a r a c t e r i s t i c s o f a Large-Scale Mixe r -Se t t l e r , DP-140, E. I . du Pont de Nemours & Co., Inc. , Savannah River Laboratory, Aiken, SC, October 1956.

Colven, T. J . , " C r i t i c a l l y Sa fe Equipment f o r Agueous Sepa ra t i ons Processes . " Proceedings o f t h e Second I n t e r n a t i o n a l Conference on t h e Peaceful Uses o f Atomic Energy, - 17:555-563, United Nat ions, New York, N Y , 1959.

Colven, T. J.9 Equipment f o r Nuclear Fuel Reprocessinq, DP-239, E . I . Du Pont de Nemours & Co., Savannah River Laboratory, Augusta, GA, October 1957.

Conaway, J . E., "Solvent Ex t r ac t i on S t u d i e s : Evaluat ion of Podbielniak ~ e n t r i f ugal c o n t a c t o r . " Q u a r t e r l y Report f o r May through J u l y 1951 . NF-51-8-237, Oak Ridge National Laboratory, Oak Ridge, TN, August 24, 1951.

Cool ey , Survey,

C. R . , Liquid-Liquid Solvent Ex t r ac t i on Contac tors - A L i t u r a t u r e HW-74532, Apri 1 6 , 1962.

Cooper, V. R . and C . Groot, Design Cons idera t ions f o r a Pulse Column System. BNWL-2186, P a r t 1 , Appendix A , B a t t e l l e , P a c i f i c Northwest Labora to r i e s , Richland, WA, March 9 , 1950.

Coplan, B. V. and E. L . Zebroski , Mul t i s t age Mixer -Se t t le r . U.S. P a t e n t Office, Washington D C , J u l y 21, 1953.

U.S. 2,646,346,

Coplan, 0 . V . and J . K. Davidson, "A Review of Contact ing Equipment f o r Continuous Countercur ren t Solvent -Ext rac t ion Process ." Reactor Sc ience and Technology, TID-2008, pp. 89-1 02, March 1953.

Coplan, B. V . , Operat ion of t h e "June 9 th" Type Mixer -Se t t le r . KAPL-99, Knoll s Atomic Power Laboratory, Schenectady, N Y , November 5, 1948.

Coplan, B. V . , e t a l . , "The Pump-Mix Mixer-Settler--A New Liquid-Contactor." Chem. Eng. Progr . , 50-:403-408, 1954.

Coplan, B. V . , e t a l . , The Mul t i s t age Pump-Mix Mixer S e t t l e r , Knolls Atomic Power Laboratory, Schenectady, N Y , Apri 1 21, 1951.

Coplan, B. V . , e t a l . , The "Pump-Mix" Mixer S e t t l e r . A New Liquid-Liquid Ex t r ac to r , AECU-2639, Knoll s Atomic Power Laboratory, Schenectady , N Y , 1953.

Coplan, B. V . , and J . W. Codeing, A Miniature P i l o t P l a n t f o r High Level Sepa- r a t i o n s Processes . Knolls Atomic Power Laboratory, Schenectady, N Y , 1954.

Cramer , T. L. , "NFS F i r s t Fuel Reprocessor. " Nucl eonics , - 24: 48-52, December 1966.

Damiani, L . , e t a l . , "The Pulsed Column i n Liquid-Liquid Ext rac t ion . I . Descr ip t ion and Operation. " Engergia Nucl e a r e (Mil a n ) , 1_: 323-332, 1960.

Darby, D. O. , Comparison of Purex Process Resul t s i n Mixer S e t t l e r s and Pul se Col umns. CF-51-8-67-Del . , Oak Ridge National Laboratory, Oak Ridge, TN, August 13, 1951.

Dars i , C. R . and J . E. Feick, "Cont ro l led Cycling Ext rac t ion : Performance of an Experiment Column." Can. J . Eng., e : 9 5 - 1 0 0 , February 1971.

Davidson, J. K e y Theory of the Pump-Mix Mixer S e t t l e r . KAPL-130, Knolls Atomic Power Laboratory, Schenectady, N Y y March 11, 1949.

Davidson, J . K . 9 Belgian Symposium on Chemical Processing, I Sess ion : E g i n e e r i n g of Radiochemical P l a n t s Contactors and A u x i l i a r i e s . KAPL-1808, Knolls Atomic Power Laboratory, Schenectady, N Y y June 17, 1957.

Davidson, J . K . , Contactors and A u x i l i a r i e s . TID-7534, - 1:848-868, 1957.

Davidson, J . K . , e t a l . , Appl ica t ion o f Mixer -Se t t le rs t o the Purex Process , TID-7534, Book 1 , p. 130-151, 1957.

Dauies, G. A . , e t a l . , "Coalescence of Liquid Droplets . Cor re l a t i on o f Coalescence Times," Solvent Extr . Proc. I n t . So lvent Extr . Conf., 1:385-399, 1971.

Davies, J. T., "Interfacial Renewal." Chem. Eng. Progr., - 62:89-94, September 1 966.

Davis, A. T. and T. J. Colven, "The Effect of Mixer Design on the Efficiency of a Pump Mixer-Settler." AIChEJ, - 7:72-77, March 1961. Davis, M. W., Jr. and A. S. Jennings, "Equipment for Processing by Solvent Extraction. " In: Chemical Processing of Reactor Fuels, pp. 271-303, Academic Press, Inc. New York, NYy 1961.

Davis, M. W., Jr. and E. J. Weber, "Liquid-Liquid Extraction Between Rotating Concentric Cylinders." Ind. Eng: Chem., - 52:929-934, 1960.

Davis, M. W., et al., Liquid-Liquid Extraction, AECD-3545; UCRL-1013, Radiation Laboratory, University of California, Berkeley, CAY May 1953.

Davis, M., "Mixer-Settler Extraction Equipment." Chem. Eng. Progr., 50:188197, April 1954. -

de Amorium, H. A. L. and V . Blatt, "Operation Techinque of a Pilot Solvent Extraction Plant for the Separation of Materials of Nuclear Interest." Proceedings of I11 Interamerican Conference on Materials Technology, Buenos Aires; Centro Regional de Ayuda Tecnica, pp. 257-266, 1972.

Demarthe, J. Ma, Effect of Hydrodynamics on the Operation of the Equipment. Centre dlEtudes Nucleaire, Saclay, France, February 1973.

Demarthe, J. M.9 Liquid-Liquid Extraction: Transient Region Studies. Commissariat a llEnergie Atomique, Saclay, France, February 1973.

Detilleux, E.9 et al., Some Development Work Done at Eurochemic. European Company for the Chemical Processing of Irradiated Fuels, Moly Belgium, May 1964.

DeWitt, R., et al., Experiments Carried Out in the Eurochemic Extraction Column Pilot Plant Concerning the Co-Decontamination Cycle Flowsheet. NP-13091, European Company for the Chemical Processing of Irradiated Fuels, Mol , Belgium, October 1962.

DeWitte, Re, et al., Continuous and Automatic Holdup and Flooding Determination in Plant Extraction Columns. European Company for the Chemical Processing of b

Irradiated Fuels, Mol , Belgium, January 20, 1961.

DeWitte, R.5 The Eurochemic Pulse Columns for Countercurrent Liquid-Liquid Extraction. Eurochemic Co., Moly Belgium, 12:42-46, January 1966.

DeWitte, R. and L. Greens, The Influence of Purge Air Introduction on the Behaviour of a Pulsed, Perforated Plate Column. NP-14005, European Company for the Chemical Processing of Irradiated Fuels, Moly Belgium, April 1963.

Dierks, R. D. and N . P. Wilburn, Purex IC Column Car t r i dge Studies-Thin Fluorothene Versus Thick Linear Polyethylene f o r Sandwich Ca r t r i dge Use. HW-79717, November 25, 1963.

DiLiddo, B. A. and T. J . Walsh, "Computer S t imula t ion of Pulse Columns." Ind. & Eng. Chem., 53-:801-804, October 1961.

Doninger, J . E. and W. F. S tevens , "Dynamic Behavior of a Packed Liquid Ext rac t ion Col umn. " AIChEJ, - 14:591-599, J u l y 1969.

Doronin, V . I . and A. M. Ni kolaev, " A Study of Mass T rans fe r i n a Pulsed Ext rac t ion Column w i t h Rota t ing Flow." 1zv-Vysshykh Uchebn. Zavedenii K h i m . i K h i m . Tekhnol., 1:655668, 1964.

Doulah, M. S. and G. A. Davies, "A Queue Model t o Describe Separa t ion of Liquid Dispersions i n Ver t i ca l S e t t l e r s . " ISEC 74' , - 1 : 533.

Doyle, C. M a , Var iab le Feed and Discharge Pos i t i ons f o r Cent r i fuqa l Counter- Current Ext rac t ion Units . B r i t i s h Pa t en t 1,058,767, February 15, 1967.

Doyle, C. M e , e t a l . , "Cent r i fuga l - type Contactors ." Chem. Eng. Progr . , 64:68-74, 1968. 7

Doyle, C. M . , Adjus tab le Liquid Feed and Discharge Means f o r Cent r i fuga l Counter-Current Exchange Devices., B r i t i s h Pa t en t 1,068,680, May 10, 1967.

Doyle, C. M a , Cen t r i fuga l Countercurrent Exchanger. U.S. Pa t en t 3,292,850, U.S. P a t e n t Off ice , Washington, DC, April 25, 1966.

Duckworth, J . P. and L. R. Michels, "New Neptunium Recovery F a c i l i t y a t the Hanford Purex Plant ." Ind. & Eng. Chem. Proc. Design, - 3:302-306, October 1964.

Duckworth, J . P . , Applied Development o f t h e Pulse Column, ISO-SA-6, Isochem Inc . , Richland, WAY February 25, 1966.

Dunstan, A. E . , e t a l . , Sc ience of Petroleum, 3:9786, Oxford Un ive r s i t y Press, London, England, 1938.

Durandet, J and X. Talmont, "Liquid-Liquid Ext rac t ion . Inf luence of the Var i a t i on o f Physical P r o p e r t i e s of Sol u t i ons on Pul sedCol umn Performance. " Bull . Inform. S c i . E t Tech., g : 1 7 - 2 8 , 1960.

Durandet, J . , e t a l . , "Study o f Pulsed Columns i n Solvent Ext rac t ion ." Proceeding of the Second ~ n t e r n a t i o n a l Conference on t h e Peaceful Uses o f Atomic Energy, 1959. Geneva, 1958, United Nations, New York, N Y , 17:180-191, 1959. -

Dykstra , J . , e t a l . , "Solvent Ex t r ac t i on System f o r Enriched Uranium." Ind. Eng. Chem., - 50:161-165, 1958.

Ecc les , H. , e t a l . , "Combined Mixer -Se t t le r f o r Solvent Ex t r ac t i on Measurements." Chem. Ind. , u :616 -617 , J u l y 19, 1975.

"Economics o f Solvent Ext rac t ion ; Symposium." London, October 29: Abs t r ac t of Papers , Chem. & Ind . , pp. 393-394, April 10, 1971.

Edeleanu, L . , U.S. P a t e n t 1,651,328, U.S. P a t e n t Of f i ce , Washington DC, November 29, 1927.

Edwards, R. B. and G. H . Beyers, "Flooding C h a r a c t e r i s t i c s of a Pu l se Extrac- t i o n Column." AIChEJ, - 2:148-152, 1956.

E l i a s , E . , e t a l . , "Gamma Gauge f o r the Control of In t e r zone Layer i n an Ex t r ac t i on Tower." Nucl . Techno1 . , - 21 (1 ): 57-66, January 1974.

E l i a s , E., e t a l . , " In t e r zone Layer Control w i t h a Gamma Gauge." Trans. Amer. Nucl . Soc. , 17: 122-1 23, November 1973.

El 1 i s , E. and R. B. Beckmann, "Liquid-Liquid Ex t r ac t i on : Annual Review. " Ind. & Eng. Chem., - 57:103-106, November 1965.

E l l i s , D. A . , e t a l . , Recovery o f Uranium from Pla teau Ores by Solvent Extrac- t i o n w i t h Di -OPA. Dow Chemical Co. Western Div., P i t t s b u r g h , C A Y Apri l 4 , 1956.

E l l i s , S. R . M . , " P r e d i c t i o n o f Height Equiva len t t o a Theo re t i ca l S tage (H.E.T.S. ) i n Packed Li'quid-Liquid Ex t r ac t i on Columns. " Ind. Chemist., 28: 483-486, 1952. - E l l i s o n , C. V . , Study of Half-Inch Pu l se Column w i t h a TBP System. Oak Ridge National Laboratory, Oak Ridge, TN, May 21, 1951.

Eugenio, M. R . , The E f f e c t o f Pu l sa t i on on Liquid-Liquid Mass-Transfer Res is tances . ANL-5874, Argonne National Laboratory, Lemont, IL, J u l y 1958.

Euzen, J . P . , e t a l . , "Comparative Study o f I n d u s t r i a l Coalescing Packings Performances i n Petroleum Indus t ry . " ISEC 74' - 1:551.

Ewing, R . A . , e t a l . , P u r i f i c a t i o n of Thorium N i t r a t e by So lven t Ex t r ac t i on wi th T r ibu ty l Phosphate 1 . B a t t e l l e Memorial I n s t i t u t e , Richland, WAY s

J u l y 31, 1952. -..

"Ex t r ac t i on Unit Can be Adopted t o Many Processes . " Chem. & Eng. N . , 42-:51-52, June 22, 1964.

Fane, A. G . , e t . a l . , " E x t r a c t o r A g i t a t e s Then Sepa ra t e s . " Chem. Eng., 68:58, May 1 , 196 .

Farbu, L . , e t . a l . , "Proceedings Solvent Ex t r a t i on Conference." ISEC '74, 3:2427, Proceedings o f S o c i e t y o f Chemical Indus t ry , London, England, 1974.

Faugeras, P. and X. Talmont, Ext rac t ion Apparatus Used i n t h e Treatment of I r r a d i a t e d Fuels . Commissariat a 1-nergie Atomique, Centre d lEs tudes Nucl e a i res , Sac1 ay , France, 1960.

Feick, G. and H. M. Anderson, "Performance o f a Packed Liquid-Liquid Extrac- t i o n Column Under Control l e d Agi ta t ion . " Ind. Eng. Chem., 44:404, 1952.

Fel i x , J . R. , Countercurrent Ex t r ac t i on Tower and Ext rac t ion o f Hydro-Carbon Oi l s w i t h Phenol. U.S. P a t e n t 2,717,854, U.S. P a t e n t OfficWashington, DC, September 13, 1955.

F e l i x , J . R. and C. H. Holder, "E f f i c i ency and Capaci ty Fac tors i n Lube Ext rac t ion . " Solvent Ext rac t ion Symposium, December 12-1 5.

Fenske, M. R. and R. B. Long, "A V e r s a t i l e Mul t i s t age Ext rac t ion Unit ." Chem. Eng. Progr . , 5J:194-198, 1955.

Fenske, M. R. and B. R . Tegge, Process and Apparatus f o r Liquid-Liquid Ex t r ac t i on , U.S. P a t e n t 2,580,010, U.S. Pa t en t Of f i ce , Washington, DC, December 25, 1951.

Fenske, M. R . , e t a l . , "Ex t r ac t i on o f Petroleum Frac t ions by Ammonia Solvents . " AIChEJ, - 1 :335-341, 1955.

Fersch, K . , product ion Column Evaluat ion. Nuclear Mater ia l s and Equipment Corp., Niagra Div is ion , Lewiston, N Y , December 15, 1970.

Figg, W. S. , Laboratory S t u d i e s of Two Pul sed Mixer -Se t t le r Solvent Ex t r ac to r s . HW-28442, Hanford Works, Richland, WA, June 23, 1953.

Figg, W . S. and J . G . Bradley, Scout ing S tud ie s i n a 5.05-Inch Diameter Redox Pulse Column. HW-19023, Hanford Works, Richland, WA, January 15, 1951.

Flagg, J . F., Nuclear Engineering Program, 1947-1948. Radio-Chemistry V . TID-10174, Knolls Atomic Power Laboratory, Schenectady, N Y , April 29, 1948.

Flanary, J . R . , Purex 1A Column S t u d i e s , CF-52-4-13, Oak Ridge National Laboratory, Oak Ridge, TN, Apri l 1 , 1952.

F l e t t , D . 9 "Recent Advances i n So lvent Ext rac t ion of Metals ." Chem. Enq., 268: 465-471 , 1972. -

F l e t t , D . , e t . a l . , J . Inorg. Nucl. Chem., - 35:2471, 1973.

Flynn, A. W. and R. E. Treybal', "L iqu id -L iqu id E x t r a c t i o n i n Continuous Flow Ag i ta ted Extractors." AIChEJ, 1:324-328, 1955.

.. - Fontana, M. G. and R. W. Wol f f , V isual Observation o f L iqu id -L iqu id Spray Column Performance. Massachusetts I n s t . o f Tech., Oak Ridge, TN, November 27, 1956.

,

Foster , H. R., e t al . , "Trans ient Holdup Behavior o f a Pulsed Sieve P l a t e Solvent E x t r a c t i o n Column." Ind. & Enq. Chem. Process Design, - 9:272-278, - .

Apr i 1 1970.

Fox, J. M., "Cent i fuge Compared f o r Phenol E x t r a c t i o n o f Lube." Hydrocarbon Process & Pet Ref iner . 42: 133-1 38, September 1963.

Franca, J. M. and J. Messano, Dimensioning I n d u s t r i a l Pulsed Columns i n Uranium P u r i f i c a t i o n by t h e I n d i r e c t HTU Method. IEA-343, I n s t i t u t o de Energia Atomica, Sao Paulo, B r a z i l , May 1974.

F r i e d e r i chs, S. L. , e t a1 . , Pulse Column Studies Using STR and S I R Feed Solut ions. IDO-14312, P h i l l i p s Petroleum Co. Atomic Energy Div. , Idaho Fa1 1 s, I D , . September 27, 1954.

F r i t z , "Treatment Method i n F i ss ionab le Ma te r ia l Reprocessing." Neue. Tech., 9:21-26, February 1967. - F u j i t a , S., e t a l . , "Holdup and Flooding V e l o c i t y i n Spray Columns." Chem. Eng., E : l 64 -171 , 1951.

Gal, I. I. and A. L. Ruvarac, P re l im ina ry Experiments on t h e Separat ion o f Uranium, Plutonium and F i s s i o n Products by Solvent Ex t rac t i on . 1961.

Garner, F. H., e t a l . , "Per fora ted-P la te Extraction-Column Performance and Wett ing Charac te r i s t i cs . " AIChEJ, - l:l85-192, June 1955.

Gaska, R. A., Single-Stage Pressure Ex t rac to r . " Chem. Eng., z : 1 5 8 , J u l y 8, 1963.

Gawlowska, W., "Universal Laboratory Ex t rac to r Working Continuously." Nukleonika, - 18(8):361-368, 1973.

Gayler, R. and H. R. C. P r a t t , "Holdup and Pressure Drop i n Packed Columns." Trans. I n s t . Chem. Engrs., 29(1):110-125, 1951.

. -

Gayler, R. and H . R . C . P r a t t , "Liquid-Liquid Ext rac t ion . V . Fu r the r ~ t b d i e s o f Droplet Behavior i n packed ~ o l u m n s . " Trans. I n s t . Chem. Engr., 31 (1 ) : 69-77, 1958. -

Gayler, R . , e t a l . , "Liquid-Liquid Ext rac t ion . IV. Fu r the r Study of Holdup i n Packed Columns." Trans. I n s t . Chem. Engrs., - 31:57-68, 1953.

Geier, H. and U . V . Knorre, "Design of and Experiments with P i l o t Mixer- S e t t l e r s f o r the Karlsruhe ~ e p r o c e s s i n g p l an t ; " Kerntechnik, 2~234-235 , June 1967.

Geier,, R. G . , Appl ica t ion of the Pulse Column t o t h e Purex Process . TID-7534, 1 : 107-1 29, 1957. (HW-49542) -

Geier , R. G. and H . M. Jones , Development of I n t e r f a c e Control Systems f o r Use on Pulse Columns, May 30, 1955.

Geier , R. G . , "Improved Pu l se Ex t r ac t i on Column Car t r i dges . " Proceedings of the Second I n t e r n a t i o n a l Conference on t h e Peaceful Uses of Atomic Enerqy, Geneva, 1958. United Nations, New York, N Y , - 17:194-195, 1959.

Gerster, J . A . , "Ex t r ac t i on E q u i l i b r i a . " Chem. Enq. Progr . , - 62:62-66, September 1 966.

Goffman, P . , e t a l . , Laboratory Mixer -Se t t le r Ex t r ac to r LMOM2. I n s t i t u t e of Nuclear Research, Warsaw, Poland, 1971.

Goldacker, H . , " E l e c t r o l y t i c Pu/U Separa t ion i n t h e Purex Process; Progress w i t h Fuel of High Plutonium Content." Presented a t Kernforschungszentrum, Karlsruhe, Germany, December 1973.

Goodlet t , C. B - , Performance of a Cent r i fuga l Mixer -Se t t le r a s a Phase Separa tor . DP-1140, E. I . DuPont de Nemours and Co., Savannah River Laboratory, Aiken, SC, June 1968.

Gorbanov, A. I . , e t a l . , Thermodynamic Nature of Hyperfine Emulsion Formation a t t h e Ex t r ac t i on , ISEC '74, - 1 :517, 1974.

Goumondy, J . P . , " L a t e s t Innovat ions i n Equipment." Presented a t Cea Centre d lE tudes Nucleaires de Fontenay-aux-Roses, 92, France, 1974.

Gouroj i , I . C . , e t a l . , "Mass T rans fe r i n Rota t ing S ieve Disk Contactor ." Chem & Process Eng, - 52:67-69, May 1971.

Green, H . , "Separa t ions Using So lven t Ex t r ac t i on . " Me ta l l u rg i a , x :143-149 , 201-204, 255-256, 299-303, September-December 1964.

Greskovich, E. J . , "Spray Tower Operat ions w i t h Packed Drople t s . " Ind & Enq Chem Process Design, - 8:493-595, October 1969.

G r i f f i t h , W. L., e t a l . , The E x t r a c t i o n o f Coba l t f rom N icke l i n a Pulse Column. Thesis, Massachusetts I n s t . o f Tech., 1952.

Groenier, W. S., e t a l . , F lood ing i n Per fo ra ted-P la te Pulsed E x t r a c t i o n Columns: A Survey of Reported Experimental Data and Cor re la t i ons , and t h e

. . P resen ta t i on of New C o r r e l a t i o n s Wi th Physica l P rope r t i es , Opera t i ng Var iab les, and Col umn Geometry. ORNL-3890, Oak Ridge Nat iona l Laboratory, Oak Ridge, TN, March 1966.

Grussendorf, 0. W., "Two New Devices f o r So lvent Ex t rac t i on . " Chem & Ind, pp. 52-54, January 8, 1966.

Guccione, E., " F i r s t Chemical Route f o r Molybolenum Processing: Process Flowsheet." Chem Eng, - 74:140-142, January 16, 1967.

Guccione, E.9 "Plutonium and Uranium v i a So lvent E x t r a c t i o n f rom Nuclear .

Fuels." Chem. Eng., z :148-150, December 7, 1964. . '

Guto f f , E. B., " I n t e r s t a g e M ix ing i n an Oldshue-Ruslton L i q u i d - L i q u i d Ex t rac- t i o n Column." AIChEJ, - 11 :712-715, J u l y 1965.

Guyer, e t a l . , "An I n v e s t i g a t i o n o f an E x t r a c t i o n Column." Helv. Chim. Acta., 38:955-959, June 1955. -

Haas, P. A. and A. C. Jealous, Thorex So lvent Recovery: Development o f Ca l c i um Hydroxide S l u r r y Process. Oak Ridge Nat iona l Laboratory, Oak Ridge, TN, February 16, 1955.

Haas, P. A * , Engineer ing Development o f a Foam Column f o r Countercurrent Sur face-L iqu id E x t r a c t i o n of Surface-Act ive Solutes. Thesis, Oak Ridge Nat iona l Laboratory, Oak Ridge, TN, June 1965.

Haas, P. A. and H. F. Johnson, "Foam Columns f o r Countercurrent Surface-Liquid E x t r a c t i o n o f Sur face-Ac t ive Solutes." AIChEJ, - 11:319-324, March 1965.

Habsieger, D . 9 e t a l . , " P u r i f i c a t i o n o f I r o n by Di -n-hepty l S u l f o x i d e i n a Pulse Column." Ann. Chim., !4(2):141-147, 1974.

Hafez, M. M., e t . a l . , "Holdup and F lood ing i n Rec ip roca t ing-P la te Ex t rac to rs . " 8.

ISEC 74' , - 2:1671.

Hamil ton, W. R., Purex Packed Column Studies. HW-60806, June 19, 1959.

Hamil ton, W. R., I n f l u e n c e of Design and Operat ing Var iab les on L i q u i d Coalescence i n Pulse Columns. For p resen ta t i on a t t h e 45th Nat iona l Meet ing of t h e American I n s t i t u t e o f Chemical Engineers, Cleveland, OH, May 9, 1961, . - December 7, 1960.

Hami 1 ton, W. R. , Coalescence i n Pul se Columns . HW-56281, General E l e c t r i c Co. Hanford Atomic Products Operat ion, Richland, WA, June 24, 1959.

Harnmond, V . L . , e t a1 . , Pul se Generators f o r Sol ven t Ex t r ac t i on Columns. For p re sen t a t i on a t Regional Meeting o f American I n s t i t u t e of Chemical Engineers, Rich1 and, WAY November 8 , 1962, October, 26, 1962. (HW-SA-2817)

Hancher, C. W . , Component Study f o r a 36-In. Riggins Contactor : Problem Statement. Oak Ridge National Laboratory, Oak Ridge, TN, February 10, 1956.

Hancher, C. W . , Uranium Recovery From Ore by a Higgins Ion-Exchange Contactor a t Grand Junc t ion P i l o t P l a n t , Oak Ridge National Laboratory, Oak Ridge, Tn, J u l y 1 , 1957.

Hanson, C . , "Recent Research i n Solvent Ext rac t ion ." Chem. Eng. 75(19):135-142, 1968.

Hanson, C. , "Sol vent E x t r a c t i on--A Neglected Separa t ion Process?". Chem. Process , 14(4):6-11, 1968. -

Hanson, C . , "Solvent Ex t r ac t i on Technology." Rep. Prog. Appl. Chem. - 53:654-681, 1 968.

Hanson, C . , e t a l . , "Proceedings I n t e r n a t i o n a l Solvent Ext rac t ion Conference." Proceedings of t h e Soc i e ty o f Chemical Indus t ry , ISEC174, - 3:2401, 1974.

Hanson, C . , ed . , "Recent Advances i n Liquid-Liquid Ex t r ac t i on . " Pergamon Press, Oxford, England, 1971.

Hanson, C . , "Solvent Ex t r ac t i on . Theory, Equipment, and Commercial Operat ions." Chem. Eng., 75(18):79-98, 1968.

Hanson, C. , e t a1 . , "Di rec t Contact Heat T rans fe r Between Immiscible Liquids i n a Mixer -Se t t le r Apparatus." ISEC '71 , - 1:270.

Hanson, C. and J . Ingham, "Solvent Ex t r ac t i on . " Chem. & Ind. , pp.939-940, May 29, 1965.

Hanson, C. and M. J . S. Smith, "Ten ta t i ve Designs f o r TWO, Geometr ical ly Eversafe, Mixer -Se t t le rs f o r High Volumetric ~ h r o u g h ~ u t s . " U . K. A t . ~ n e r g ~ Author i ty , 22(R) : 10 pp., 1961.

Harmathy, T. , "Theory o f Throughput i n Ext rac t ion Spray Towers." Acta. Tech. Acad. Sc i . Hung., E:209-243, 1955.

H a r r i s , K., e t a l . , "Liquid-Liquid Ex t r ac t i on : Annual Review." Ind. & Enq. Chem., 58-:97-103, November 1966.

Har t , H. P . and T. H . f un l ey , "Pulse Columns i n Uranium Refining. Some Engineering Aspects o f The i r Operat ion i n t h e Government Meta l lu rg ica l Laboratory. " - - PEL, 121 ( 3 ) : 222-233.

Hartlage, J . A. and A. D. Cronberg, "Correlation of Kelex Copper Dis t r ibut ion Data w i t h Extraction and Str ipping Mixer S e t t l e r Performance." ISEC '74, p. 747.

Hartland, G . 9 "Counter-Current Extraction." Pergamon Press, Oxford, England, 1970. :

Hartzell , L. O . , e t a1 . , The Sol vent-Extraction Performance of Redox IC Columns (ANL June 1948 Flowsheet) Using Raschig Ring Packing, and Unirradiated Uranium. Hanford Works, Richland, WAY August 22, 1949.

Harwell , B . , e t a1 . , The Removal of Fission Products from Solution w i t h a Precipitator-Column Treatment. Par t 2. P i l o t Plant T ra i l s . Great Br i t ian Atomic Energy Research Establishment, Hawell, Berks, England, January 1957.

Harwell, B . , e t a l . , Counter-Current Liquid-Liquid Extraction i n Annulus Columns w i t h Shearing Motion. Great Br i t ian Atomic Energy Research Establishment, Harwell, Berks, England, September 22, 1952.

Hayworth, C. B. and R. E . Treybal, "Drop Formation i n Two-Liquid-Phase Systems." Ind. Eng. Chem., 42:1174, 1950.

Hazlebeck, D. E. and C. J . Geankoplis, "Axial Dispersion i n a Spray-Type Extrac- t ion Tower. " Ind. & Eng. Chem. Fundamentals , - 2: 31 0-31 5 , November 1963.

Hazen, W. C . , "Performance of the Kermac Solvent Extraction Plant ." Min. Cong. J . , %:56-59, Ju ly 1960.

Hennico, A . and T. Vermeulen, "Nonequilibrium Thermodynamics Theory f o r Con- cen t ra t ion P ro f i l e s i n Liquid Extraction." AIChEJ, - 8:394-403, July 1962.

Henton, J . E . and S. D . Cavers, "Continuous-Phase Axial Dispersion i n Liquid- Liquid Spray Towers." Ind. & Enq. Chem. Fundamentals, - 9:384-392, August 1970.

Henton, J . E . , e t a l . , " In ternal Sampling of Liquid-Liquid Spray Columns a t Steady S t a t e . Methods, Material Balances and Application t o Tracer Studies Without Mass Transfer ." ISEC '71, 2:1302.

Hesson, G. M . , e t a l . , Organic Continuous Pulse Column Cartr idge f o r Purex A-Type Col umns . HW-49181, March 22, 1957.

Hicks, T. E . , e t a l . , The Chelate Process. V . Invest igat ion i n Horizontal Extractors. University of Cal i fornia , Berkeley, C A , Ju ly 29, 1949.

Hies ter , N. K . , e t a l . , Ion Exchange of Trace Components i n a Counter-Current Equi 1 i bri urn Stage Contactor. Stanford Research I n s t i t u t e , Apri 1 1 , 1953. . - Hiester , N . K . , e t a l . , Engineering and Economic Evaluation of Counter-current and Fixed Bed Ion Exchange Processes. Stanford Research I n s t i t u t e , June 26, 1953.

Hies t e r , N. K . , e t a l . , Counter-current Ion Exchange with Gross Components. P a r t 1. In an Equi l ibr ium Stage Contactor. P a r t 2. In a Continuous Counter- c u r r e n t Column. Stanford Research I n s t i t u t e , June 25, 1953.

H i e s t e r , K . , e t a1 . , " I n t e r p r e t a t i o n and Cor re l a t i on of Ion Exchange Column Performance Under Nonlinear E q u i l i b r i a . " AIChEJ, - 2:404-411, September 1956.

Hinze, J . 0. and C. L. Mantel l , "Fundamentals of t h e Hydrodynamic Mechanism of S p l i t t i n g Up i n Dispersion Process. " Solvent ~ x t r a c t i o n - Symposium, December 12-1 5 , 1954.

Hody, D. , Chemische Rundschav, - 28:9, 1975.

Hoffing, E. H. and F. J . Lockhart , "A Cor re l a t i on of Flooding V e l o c i t i e s i n Packed Columns. " Chem. Eng. Proqr. , =:94-103, 1954.

Hoffmann, P. M . , P re l iminary Ca lcu l a t i ons of the Hydrocyclone Contactor Type M.P.H. I n s t i t u t e of Nuclear Research, Warsaw, Poland, 1969.

Holmes, J . H . and A. C. Scha fe r , "Some Operat ing C h a r a c t e r i s t i c s of the Pump- Mix Mixer S e t t l e r . " Chem. Eng. Progr . , z :201-204 , May 1956.

Honekamp, J . R. and L. E. Burkhart , "Role o f the Packing i n a Scheibel Ext rac tor . " Ind. & Enq. Chem. Process Design, - 1:176-184, Ju ly 1962.

Hopp, H a , J r . and R . B. Smith, "An Algebraic Approach t o Calcu la t ing the Sol- ven t Ext rac t ion o f Complex Mixtures." Solvent Ext rac t ion Symposium, December 12-1 5, 1954.

Howells, G. R e , e t a l . , "The Chemical Processing o f I r r a d i a t e d Fuels From Thermal Reactors ." Proceedinqs o f t h e Second I n t e r n a t i o n a l Conference on t h e Peaceful Uses of Atomic Energy, Geneva, 1958. - 17:3-24, United Nations, New York, N Y , 1959.

H u , S. and R. C. Kintner , "The F a l l of S i n g l e Liquid Drops Through Water." AIChEJ, 1:42-48, 1955.

Huck, C. E . , Densi ty Monitor f o r Purex HA Column. General E l e c t r i c Company, Hanford Atomic Products Operat ion, Richland, WA J u l y 16, 1958.

Hughs, D. J . , e t a l . , "Reactor Operat ional Problems." Proceedinqs of t h e F i r s t Nuclear Engineering and Sc ience Congress Held a t Cleveland, OH. 1957.

Hunt, C . , Capacity Fac to r s i n the Performance of Pe r fo ra t ed P l a t e Columns. Thes i s , Un ive r s i t y o f C a l i f o r n i a , Berkley, CA, October 1954.

Huppert, K. L . , "Performance of Ex t r ac t i on Equipment i n t h e Wak-Pilot P l a n t . " Proceedings of t h e I n t e r n a t i o n a l Sol ven t Ex t r ac t i on Conference, ISEC ' 74, September 1974.

Hutchins, R. P., "New S t a t i o n a r y Basket Ex t r ac to r . " Am. Oil Chem. Soc. J.9 37:674-675, December 1960. - ICPP So lven t Ex t r ac t i on System Range and O p e r a b i l i t y Using Hexone a s the E x t r a c t a n t . American Cyanamid Company, Atomic Energy Div., Idaho F a l l s , ID, November 24, 1952 (S ,ecre t ) .

Ige l s rud , I . , e t a1 . , Progress Report f o r t h e Month of August, 1949. B a t t e l l e Memorial I n s t i t u t e , Columbus, O H , 1949.

Ingham, J . , e t a l . , "Backmixing i n a KUhni Liquid-Liquid Ex t r ac t i on Column." ISEC '74 , 1_:1299.

Ingham, J . , "Chapter 8 . " Recent Advances i n Liquid-Liquid Ex t r ac t i on . C. Hanson, ed., Pergamon P re s s , Oxford, England, 1971.

Ingham, J . , "Solvent Ex t r ac t i on i n I s r a e l . " Chem. & Ind. , pp. 1863-1867, November 4 , 1967.

I r i s h , E. R . 9 Descr ip t ion of Purex P l a n t Process . Hanford Atomic Products Operat ion, Richland, WA, May 19, 1959.

I r i s h , E. R . , "Appl ica t ion o f t h e Packed Column t o t h e Redox Process . " Proceedings of Symposium on t h e Reprocessing of I r r a d i a t e d Fue l s , B rus se l s , Belgium, TID-7534, - 1:69-82, May 20-25, 1957.

I r i s h , E. R e , Appl ica t ion of the Packed Column t o t h e Redox Process . TID-7534, 1:69-82, 1957. -

I I r v i n e , A. R . , Pu lse Pumpinq: A Means f o r T rans fe r of Pulse Column F lu ids . I Oak Ridge National Laboratory, Oak Ridge, TN, November 1 , 1957.

I I s h i g o k i , S. and H. R. Ka iser , "Cen t r i fuga l E x t r a c t o r Scores a t Lube P l a n t . " I Pet Management, 35: 194-1 96, May 1963.

I I s aac , N. and R. L. DeWitte, "New Type of Countercur ren t Column f o r t h e I Zirconium-Hathium S e p a r t a t i o n . " AIChEJ, - 4:498, December 1958. I I

I Jackson, I . D . , e t a l . , "An Improved S e t t l e r Design i n Hydrometal lurgical So lven t Ex t r ac t i on Systems." ISEC ' 74 , - 1:567.

I . I Jackson, I . D. , e t . a l . , AIChE Symposium S e r i e s No. 42, Paper 15, Proceedings I o f the I n s t i t u t e o f Chemical Engineers . London, England, 1957.

I Jackson, M. L., e t a l . , "Sur face E f f e c t s i n a Pulsed Packed Column." AIChEJ, I - 8: 659-662, 1 962.

Jackson, R e , "Formation and Coalescence of Dispersions." Chem. Eng. Progr . , 62:82-88, September 1966. -

Jacobson, F. M. and G. H . Beyer, "Operating C h a r a c t e r i s t i c s of a Cent r i fuga l Ex t r ac to r . " AIChEJ, - 2:283-289, September 1956.

Jacques, G. L . , e t a l . , Lonqi tudinal Dispersion i n Packed Ext rac t ion Columns. Univers i ty of C a l i f o r n i a , Berkeley, CA, April 1959. (UCRL-8658)

Jann, P. E . and H . K. Zimmerman, J r . , "Improved Ext rac t ion Apparatus." Chemist-Analyst, - 39:72, 1950.

Jansen, G. and G. L . Richardson, Purex Pulse Column Studies-1960. HW-68846, February 22, 1961.

Jansen, G . , J r . , 2D Column Scrub Sec t ion S tud ie s . June 29, 1961.

Jasny, G; R . , e t a l . , The Design, Cons t ruc t ion , and Operation of a Pulse Column f o r the P u r i f i c a t i o n of Zirconi um. KT-69, Massachusetts I n s t i t u t e of Tech., Oak Ridge, TN, May 3, 1950.

J ea lous , A. C. and E . C. S tewar t , A Review of t h e Re la t i ve Merits of Packed Columns, Pulse Columns, Mixer -Se t t le r Mechanism, and Cent r i fuga l Contac tors . CF-51-1-10, Oak Ridge National Laboratory, Oak Ridge, TN, January 8, 1951.

J ea lous , A. C . and E. Lieberman, "The Concatenated Pulse Column." Chem. Eng. Progr . , - 52(9) : 366-370, September 1956.

J ea lous , A. C. and H. F. Johnson, "Power Requirements f o r Pulse Generation i n Pulse Columns." Ind. Eng. Chem., - 47:1159, 1955.

J e f f r e y s , G. V . , "Ex t r ac t i on Column Design." Chem. & Process Eng., 9 :111-115 , November 1 968.

J e f f r e y s , G. V . , "E f f i c i ency o f Liquid Ex t r ac t i on Processes . " Chem. & Process Eng., g :117-119 , March 1962.

J e f f r e y s , G. V. and C. J . Mumford, "Droplet-Breakup Mechanisms i n a Rotat ing Disk con tac to r . " Sol vent Extr . , Proc. 1n t . s o l v e n t Extr. Conf. , - 1 :667-679,- 1971.

J e f f r e y s , G. V . and G. A. Davies, "Chapt. 14." Recent Advances i n Liquid- Liquid Ext rac t ion . C. Hanson, ed . , Pergamon Press, Oxford, England, 1971.

Jenne, O . , "Engineer ing P r i n c i p l e s i n t h e Design of t h e Eurochemic Reprocess- ing P l a n t . " Chem. Ingr . Tech., - 33:139-145, 1961.

Jennings , A. S . , A Min i tu re Cent r i fuga l Contactor . E. I . du Pont de Nemours & Co., Inc. , March 1962.

J i c k l i ng , R. S . , e t a1 . , "Study of S t r i p p i n g Uranium Complex from an Amine . . - ~ x t r a c t ~ w i t h Aqueous S a l t ~ o l u t i o n s . " Can. J . Chem. ~ n g ; , 46-:53-56, February 1968.

Johannisbaver , W. and G. Ka iser , "Scal e-up o f Air Pulsed Mixer-Set t l ers f o r t h e Reprocessing o f Nuclear Fuels ." Proceedings of I n t e r n a t i o n a l So lven t Ex t r ac t i on Conference. Lyons, France, September 8-14, 1974, p. 243-283, S o c i e t y o f Chem. Indus t ry , 1974.

Johansson, H . and J . Rydberg, "Solvent Ex t r ac t i on S t u d i e s by t h e AKUFVE Method. IV. Spec t rophotomet r ic Determinat ion of t h e D i s t r i b u t i o n o f Ace ty lace tone ." Acta. Chem. Scand., - 23(8) :2797-2807, 1969.

Johnson, A . I . , and J . Marangozia, "Mixing S t u d i e s on a Pe r fo ra t ed D i s t i l l a t i o n P l a t e . " Can. J . Chem. Engr. , - 36:161-168, 1958.

Johnson, A. I . and E . A. L . Levergue, "Holdup i n Liquid-Liquid Ex t r ac t i on Columns." Can. J . Chem. Engr., - 39:37-41, 1961.

Johnson, H. F., Theo re t i ca l Study of S ingle -Transfer Line Concatenated Pulse Column Systems. Oak Ridge National Laboratory, Oak Ridge, TN, June 19, 1959.

Johnson, R . , "Tables f o r t h e Ca lcu l a t i on o f Operat ing Parameters f o r Compound Solvent -Ext rac t ion Columns." AIChEJ, - 13:607, May 1967.

Jones, S . , On t h e Behavior o f a Pulsed Ex t r ac t i on Column. Thes i s , Un ive r s i t y of Michigan, 1962.

Joseph, C. J . , e t a l . , "Technological Experience wi th Ex t r ac t i on Equipment a t Eurochemic." Proceedings of t h e I n t e r n a t i o n a l Solvent Ex t r ac t i on Conference, Vol. I and 11. S o c i e t y o f Chemical Indus t ry , London, England, 1971.

Josephson, P . R . and L . E . Burkhart , "A Countercur ren t Mul t i s t age , Fused Sal t-Mol t e n Metal Ex t r ac to r . " Trans. Am. Nucl . Soc. , - 4: 352, 1961 . Judson, B. F . , "Performance o f a Plutonium Reflux So lven t E x t r a c t o r System." TID-7534, 1:296-302, 1957.

Kado. T. and D. M. Himmelblau, " S t o c h a s t i c Analys i s of a Countercur ren t TWO-phase Absorpt ion o r ~ x t r a c t i o n Column. " I&. & Eng. Chem. Process Design, - 12:321-328, J u l y 1973.

Kafarov, V. V . and Y . I . D-ytnerskii , "H.ydrod.~namics and Mass T rans fe r i n Packed Absorption ~ o l umns ." Trudy ~ o s k o v . khim-~ekhnol . I n s t . i m . D . I . Mendeleeva, - 23:165-174, 1956.

Kafarov, V . and V. I . Trofimov, "Analysis o f Performance of Packed Towers Under Conditions o f Free Turbulence. " Zhur. Pri kl ad. K h i m . , a :211-221 , 1957.

Kafarov, V . V . and B. M. Babanov, " I n t e r f a c i a l Sur face o f Mutually In so lub le Liquids Produced by Mechanical Mixing w i t h an Impel 1 er. " Zhur. Pri kl ad. Khim., z :789-796 , 1959.

Kahn, D. R. and T. Vermeulen, "Development of a Jet-Mixed Ext rac t ion Column." U.S. Clearinghouse Fed. Sc i . Tech. Inform. , PB-183636:88, 1969.

Karpacheva, S. M . , e t a l . , "Pu l sa t i ona l Apparatus f o r Leaching and Dissolving Processes . " Ref. Z h . K h i m . , 206-21 2, 1974.

Karpacheva, S. M. and S. F. Medvedev, "Sorpt ion from Pulps i n Pu l sa t i ona l Countercurrent Flow Columns." Razrabotka i Primenenie Pu l sa t s ion , Apparatury, p. 189-199, 1974.

Karpacheva, S. M . , e t a l . , Pu l 'S i ruyushchie Eks t rak tory . MOSCOW, Atomizdat, 1964.

Karr, A. E . , "Performance o f a Rec iproca t ing-Pla te Ext rac t ion Column." AIChEJ, 5 : 446-452, December 1 959. -

Karr, A. E . and T. C . Lo, Proceedings I n t e r n a t i o n a l Solvent Ext rac t ion Conference, ISEC '71, 1:299, Soc i e ty o f Chemical Indus t ry , London, England, 1971.

Kato, Y . , "Control o f Pu l se Columns f o r Nuclear Fuel Processing." J . Japan Assoc. Autom. Control Enqr., - 7:525-534, September 1963.

Kehat, E. and S. Sideman, "Chap. 13." Recent Advances i n Liquid-Liquid Ex t r ac t i on , C. Hanson, ed. , Pergamon P re s s , Oxford, England, 1971.

Kehat, E . and R . Letan, "Operation o f a Spray Column w i t h a Dense Packing of Drops." Ind. Eng. Chem. Process Des. Develop. , L(3) : 385-389, 1968.

Kehat, E . and R . Letan, "Role of Wakes i n the Mechanism of Ext rac t ion i n Spray Columns." AIChEJ, - 17:984, 1971.

Keith, F. W. and A . N . Hixson, "Liquid-Liquid Ext rac t ion Spray Columns-- Drop Formation and I n t e r f a c i a l T rans fe r Area." Ind. Eng. Chem., - 47:258, 1955.

Kerimov, R. M . , "Optimum Quick-Response Control System f o r a Fractionating Column." Za Tekh. Progr., - 9:l-3, 1972.

Kertes, A. S. and Y . Marcus, ed., Solvent Extraction Research. Wiley, N Y , 1970.

Kiessl ing, R . , "The Influence of Phase Transfer Discontinuity of the Efficiency " . of In te rmi t ten t ly Pulsed Liquid-Liquid Countercurrent Extraction Columns." Kernenergie, - 6:168-172, April 1963.

Kiessl ing, R. , "Optimal Testing of Mu1 t i-Stage Countercurrent Liquid-Liquid- Extraction Columns." Kernenergie, 5:540-543, October 1963.

King, J . and E . Rhodes, "Solvent Extraction: Rotating Disc Contactor." Manuf. Chem., - 35:51-55, June 7964. . Kingsbaker, C. L . , "Methods and Results of Purging Extractors." Am. Oil Chem. Soc. J a y - 45, August 1968.

Kishbaugh, A. A . , Performance of Mixer-Settlers in the Thorex Process. E. I . du Pont de Nemours & Co., Aiken, SC, 1966.

K i shbaugh, A. A. , Performance of a Mu1 t i -Stage Centrifugal Contactor. DP-841, E. I . du Pont de Nemours & Co., Inc., October 1963.

Kisl iak, P . , e t a l . , Liquid-Liquid Extraction. Rensselaer Polytechnic In s t . , July 1 , 1952.

Klitguard, J . and J . H . Goode, Evaluation of Small Modified Cen Mixer-Settlers f o r the Extraction of Uranium and Thorium i n a Hot Cell Fac i l i t y . ORNL-TM-1256, Oak Ridge National Laboratory, Oak Ridge, TN, August 30, 1965.

Klopfenstein, R . K. and D . S. Arnold, "Recent Developments in Solvent Extrac- t ion Technology." J . Metals, - 18:1195-1197, November 1966.

Knapp, L . , e t a l . , A Polyethylene Box-Type Mixer-Settler Extractor. Iowa S t a t e College, Ames, IA, January 1958.

Koirtyohann, R. and J . W . Wen, "Cr i t i ca l Study of the APCD-MIBK Extraction System f o r Atomic Absorption." Anal. Chem. - 45:1986-1989, October 1973.

Koski, 0. H . , Invention Description-Devises f o r Improving the Efficiency of ..-

Separation i n Pulsed Liquid-Liquid Extraction Columns. HW-39938, General E l ec t r i c Co. Hanford Atomic Products Operation Richland, WA, November 15, 1955.

Krieg, N . G . , e t a l . , P i l o t Plant Development of a Su l fur ic Acid Solvent Treatment Plant Process. Mallinckrodt Chemical Works, November 30, 1959.

Kung, E . Y . and R . B. Beckman, "Dispersed-Phase Holdup i n a Rotating Disk Extraction Column." AIChEJ, 1:319-324, June 1961.

L a i t y , D. S. and R. E. Treybal, "Dynamics o f L i q u i d A g i t a t i o n i n t h e Absence of an A i r - L i q u i d I n te r face . " AIChEJ, - 3:176, 1957.

Landav, J. and R. Hovl ihan, "Thoughput of Ro ta t i ng Disc Contactors: A Review." Can. J. Chem. Eng., z :338-344, June 1974.

Langlo is , G. E., e t a l . , "Determinat ion o f I n t e r f a c i a l Area i n Unstable Emulsions by L i g h t Transmission." Rev. Sci . I n s t . , 3:360-363, 1954.

Larson, D. L., e t a1 . , Pul se-Col umn Operat ing Condi t ions f o r Uranium Recovery f rom Waste So lu t ions . Massachusetts I n s t . o f Tech., Oak Ridge, TN, September 13, 1950.

Lash, L. D., "Shrouded Mixer I m p e l l e r i n Solvent E x t r a c t i o n o f Uranium." Min. Eng., u:1161-1164, November 1958.

Laskorin, B. N., e t a l . , "Appartus f o r t he E x t r a c t i o n o f Uranium and Rare Meta ls f rom Aqueous So lu t ions . " Atomnaya Energ., c :503-513, June 1962.

Laskorin, B. N., e t a l . , " E x t r a c t i o n as a Means o f Recovering Uranium and Rare Meta ls from Water So lu t ions . " Atomnaya Energ., g:503-513, June 1962.

L a t e s t Equipment f o r U n i t Operat ions: Ex t rac t ions . " Can. Chem. Process, 43:67, February 1959. - Lawroski, S. and M. Levenson, Redox Process--A Solvent E x t r a c t i o n Reprocessing Method f o r I r r a d i a t e d Uranium. TID-7534, - 1:3-21, 1957.

Lawroski, S. and M. Levenson, Redox Process--A Solvent E x t r a c t i o n Reprocessing Method f o r I r r a d i a t e d Uranium. Symposium on t h e Reprocessing o f I r r a d i a t e d Fuels, TID-7534, - 1:45-68, Brussels, Belgium, May 20-25.

Lehman, H. R., Mechanical C h a r a c t e r i s t i c s and Performance o f L iqu id -L iqu id E x t r a c t i o n Columns. Thesis, U n i v e r s i t y o f C a l i f o r n i a , Rad ia t ion Lab. , Berkel ey , CA, November 1951.

Lentz, H., "F looding Behavior, Optimum Working Po in t , and E f f i c i e n c y o f Separat ion o f Packed Columns. " Chem. Ing. Tech. , - 41 :855-861, August 1968.

L i , N. N. and E. N. Z ieg le r , " E f f e c t o f A x i a l M ix ing on Mass Trans fer i n E x t r a c t i o n Columns." Ind. & Eng. Chem., - 59:30-36, March 1967.

L idd le , C. J. and G. S. Virdee, "Hydrodynamics o f L iqu id -L iqu id Spray Columns." Chem. & Proc. Eng. , 51: 79-81 , November 1970, 52: 57-62, January 1971 . Lieberman, E. and A. C. Jealous, A p p l i c a t i o n o f t h e Pulse Column f o r Uranium Recovery From K-25 Wastes. Oak Ridge Nat iona l Laboratory, Oak Ridge, TN, November 19, 1953.

Lindstri jm, 0. and S. F l i n k , "New Equipment f o r L i q u i d - L i q u i d Ex t rac t i on . " ASEA Research , 1, Vasteras, Sweden, 1962.

Lo, T. C. and A. E. Karr, "Development o f a Laboratory-Scale Rec ip roca t ing P l a t e E x t r a c t i o n Column. " Ind. & Enq. Chem. Process Desiqn, - 11 :495-500, October 1972.

Logsdai l , D. H., " A Note on the Use of Pulsed P l a t e Columns f o r t h e Primary Separat ion Process." Great B r i t i a n Atomic Energy Research Establ ishment, Harwel l , Berks, England, May 24, 1955.

Logsdai l , D. H., e t a l . , " L i q u i d - L i q u i d Ex t rac t i on . P a r t X I I . F lood ing Rates and Performance Data f o r a Rotary D isc Contactor." Trans. I n s t . Chem. Engrs., - 35:301-315, October 1957.

Lossda i l , D. H. and J. D. Thornton. "Develo~ments i n Ho r i zon ta l Pulsed Con- t a c t o r s f o r L i q u i d - L i q u i d ~ x t r a c t i o n ~roces;es." Reactor Techno1 . , - 1 : 15-24, A p r i l 1959.

Logsdai l , D. H. and J. D. Thornton, " L i q u i d - L i q u i d Ex t rac t i on . P a r t X I V . The E f f e c t o f Column Diameter Upon t h e Perfromance and Throughput o f Pulsed P l a t e Columns." Trans. I n s t . Chem. Engrs., - 35:331-342, October 1957.

Logsda i l , D. H. and L. Lowes, "Chap. 5." Recent Advances i n L i q u i d - L i q u i d Ex t rac t i on . C. Hanson, ed., Pergamon Press, Oxford, England, 1971.

Long, J., "Engineer ing f o r Nuclear Fuel Reprocessing." Gordon andBreach Science Pub l ishers , Inc. , New York, NYy 1967.

Low, A. J., "So lvent E x t r a c t i o n Recovers Isotopes f rom Nuclear P l a n t Waste So lu t ions . " Chem. Eng., 75-:64-66, August 26, 1968.

Lowe, J. T., " C a l c u l a t i o n o f t h e T rans ien t Behavior o f So lvent E x t r a c t i o n Processes." Ind . & Eng. Chem. Process Desiqn, 7:362-366, 1968.

Ludlow, 0. J., A New Approach t o Concatenat ion o f Pulsed Columns. HW-38667 Hanford Atomic Products Operat ions, Richland, W A Y August 16, 1955.

Mar, B. W. and A. L. Babb, "Long i tud ina l M ix ing i n Pulsed S ieve-P la te . . E x t r a c t i o n Column." Ind. Enq. Chem. , - 51 :1011-1014, 1959.

Marinsky, J. A. and Y . Marcus, " I o n Exchange and So lvent E x t r a c t i o n . A Ser ies o f Advances, Volume 3." I o n Exch. and So lvent Ex t r . , 3:154, 1973.

Marple, S . , J r . , e t a l . , "Deasphal t ing i n a Rotat ing Disc Contactor ." Chem. Eng. Progr . , z : 4 4 - 4 8 , December 1961.

Martin, J . J., "Analyt ical So lu t ion of Equilibrium-Stage Operat ions: Applica- t i o n t o R e c t i f i c a t i o n wi th Varying Sa tu ra t ed Entha lp ies and t o Liquid-Liquid Ext rac t ion ." AIChEJ, - 9:646-653, September 1963.

"Mass T rans fe r i n Liquid-Liquid Systems." Chem. Eng. Progr . , 57-:70-72, Noverr~ber 1961 . Mathers, W. G . , "The Development o f a Large-Scale Air-Lift Contactor ." - A t . Energy Can. Ltd., AECL-193, 1959.

Mathers, W. G. and E . E . Winter, " P r i n c i p l e s of Operation of an Ai r Operated Mixer-Set t ler ." Can. J . Eng., 37:99, 1959.

M a t t i l a , T. K. , Proceedings Solvent Ext rac t ion Conference ISEC '74 , - 1:169, Soc i e ty o f Chemical Indus t ry .

Mayfield, F. D. and W. L. Church, "Liquid-Liquid Ex t r ac to r Design." Ind. Eng. Chem., 44:2253, 1952. - - Mayfield, F. D . , e t a l . , "Pe r fo ra t ed -P la t e D i s t i l l a t i o n Columns." Ind. Eng. Chem., 44:2238-2249, 1952. - -

Mayling, A. A . , "Laboratory Solvent Ext rac tor . " Chem. Eng., 67:128, January 11, 196 . McAll i s te r , R. A. and A. D. Ryon, A Review of Pulse-Column Flooding Data and Cor re l a t i ons wi th Proposed Methods o f C o r r e l a t i o n , ORNL-TM-634 Oak Ridge National Laboratory, Oak Ridge, TN, June 6, 1963.

McCarthy, P. B . , Tef lon Bellows Pu l se Generators f o r Solvent Ext rac t ion Pulse Col umns. General E l e c t r i c Co. , Hanford Atomi c Products Operat i on, Richland, WAY January 1 , 1954.

McCarthy, P. B . 9 Purex P l a n t Small Pulse Generator Operation. General E l e c t r i c Co., Hanfsrd Atomic Products Operat ion, Richland, W A Y December 7, 1955.

McCarthy, P. B., Purex Pulse Generator Operation. HW-36836, General E l e c t r i c Co., Hanford Atomic Products Operat ion, Richland, W A Y May 11 , 1955.

McCutcheon, E. B. , S imulat ion and Control Syn thes i s f o r a Pulse Column Separa t ion System f o r Plutonium-Uranium Recovery. Ames Laboratory, Ames, IA, 1975.

McDonald, C. W e and F. L . Moore, "Liquid-Liquid Ext rac t ion of Cadmium w i t h High-Molecular Weight Amines from Iodide So lu t ions . " Anal. Chem., %:983-985, May 1973.

McFerrin, A. R. and R. R. Davison, " E f f e c t o f Su r f ace Phenomena on a Solvent Ex t r ac t i on Process ." AIChEJy z:1021-1027, September 1971.

McHenry, R. E . and J . C. Posey, An Air-Pulsed Laboratory Mixe r -Se t t l e r . Oak Ridge National Laboratory, Oak Ridge, TN, September 1964.

McKay, H. A. C . , e t a l . , So lvent Ex t r ac t i on Chemistry of Metals . Macmillian, London, England, 1965.

McKay, H . A. C . , e t a l . , "Mixer -Se t t le r Runs t o Study U(1V) a s a Reductant i n U/Pu Sepa ra t i on . " A t . Energy Res. Es tab . , Great B r i t i a n , 1963.

McLean, D. A . , " A l t e r n a t e Techniques f o r Performing E x t r a c t i o n s . " Anal. Chem., 43: 623, Apri 1 1971. -

McNamee, R . J . , "Thorex." In: Chemical Technology Div is ion Unit Opera t ions Sec t ion Monthly Progress Report f o r April 1956. Oak Ridge National Laboratory, Oak Ridge, TN, pp. 65-72, 1956.

McNamee, R. J . , Re l a t i onsh ip Between Holdup and Flooding i n a Pulsed, S ieve P l a t e Ex t r ac t i on Column. ORNL-TM-1229, Oak Ridge National Laboratory, Oak Ridge, TN, p. 110, March 1968.

Mehner, W . , e t a l . , Proceedings I n t e r n a t i o n a l Solvent Ex t r ac t i on Conference, ISEC171. Proceedings o f S o c i e t y o f Chemical Indus t ry , London, England, 2:1265, 1971. -

Mehner, W . , Counterflow Liquid Contac tor , Ger. 1,252,638, October 26, 1967.

Mensing, C. E . , Mu l t i p l e Contact Countercur ren t Ex t r ac to r . U.S. P a t e n t 2,405,158, U.S. P a t e n t Of f i ce , Washington, DC, August 6 , 1946.

Miachon, J . P . , "Solvent Ex t r ac t i on Unit Reduces Residence Time." Process Eng., pp. 79-80, December 1972.

Miachon, J . P . , La Technique Moderne, March/April 1971.

Michel, P . , "Liquid-Liquid Ex t r ac t i on Processes on the I n d u s t r i a l S c a l e . " Bul l . Inform. S c i . Tech., M : 1 9 - 2 7 , September 1973.

Michot, G. and H . F . Wiegandt, "Countercurrent Liquid-Liquid Ex t r ac t i on i n Rota t ing Mu1 t i p l e el i x . "nd. & Eng. Chem. process ~ e s i ' g n , - 10:586-592. October 1971 . M i l l e r , W. E . , e t a l . , Mixer -Se t t le r Apparatus. U.S. Pa t en t 3,663,178, U.S. P a t e n t Of f i ce , Washington, D C , May 16, 1972.

Mi lwidsky, B. M . , "Laboratory Apparatus f o r Liquid-Liquid Ex t r ac t i ons . " Chem. Ind. , - 13:411-412, 1969.

Milwidsky, B. M . , "Continuous Liquid-Liquid Ex t r ac t i on . " Soap & Chem. Spec. , 45:79-80, December 1969.

Miscellaneous. Reports from Session XIV, General Information Meeting, October 24, 25, 26, 1949. Oak Ridge, TN, 1949.

Misek, T o , "Break-up of Droplets i n an Agi ta ted Liquid-Liquid Ex t r ac to r . " Kralovopol sk S t r o j i r n a , 1: 37-43, 1961.

Misek, T., "Behavior of a Polydisperse Phase i n Column-Type Apparatus. I . Hydrodynamics, entrainment , and p a r t i a l f looding ." Co l l ec t . Czech. Chem. Commun. , 32(11) : 401 8-4031 , 1967.

Misek, T. and R. Vladimir, Pu l sa t i nq Column f o r Liquid Ex t r ac t i on . 1967.

Misek, T., "Rotary Disk E x t r a c t o r s and The i r Ca lcu l a t i ons . " Methods and Chemical Technology. 1964.

Misek, T. and V . Rod, "Chap. 7." Recent Advances i n Liquid-Liquid Ex t r ac t i on . C. Hanson, ed . , Pergamon Press, Oxford, England, 1970.

Misek, T., "The Coalescence of Droplets i n Agi ta ted Liquid-Liquid Ex t r ac to r s . " Kralovopolska S t r o j i r n a , - 1-2:13-16, 1962.

Mishra, J . C. and D. K. Dut t , "Engineering Study of Hold-up i n a Per fora ted P l a t e Pulse Column f o r the Countercur ren t Flow of Two Immiscible Liquids ." Chem. Age Ind ia , - 20(10) :845-852, 1969.

Mizrahi, J .9 e t a l . , Proceedings I n t e r n a t i o n a l Solvent Ext rac t ion Conference, ISEC ' 74, - 1 : 141, Soc i e ty of Chemical Indus t ry , London, England, 1974.

Mizrahi, J . and E . Barneu, "Compact S e t t l e r Gives E f f i c i e n t Separa t ion of Liquid-Liquid Dispersions." Process Eng., pp. 60-65, January 1973.

Moore, F. L . , "Liquid-Liquid Ex t r ac t i on of Metal Ions from Aqueous So lu t ions of Organic Acids wi th High-Molecular-Weight Amines: T r i v a l e n t Act inide- Lanthanide Elements." Anal. Chem., - 37:1235-1239, September 1965.

Moore, R. H . and J . E . Mendel, The Vibra t iona l Method f o r Measuring Dispersion , and Disengaging Time and i t s Appl ica t ions t o the Study of Emusion Problems.

Hanford Atomic Products Operat ion, Richland, WAY April 21, 1953.

Moorehead, D. H . and D. M. Himmelblau, "Optimizat ion o f Opera t ins Conditions i n a packed Liquid-Liquid Ex t r ac t i on column. " Ind. & ~ n g : hem.-~undamental s , 1 : 687, February 1 962. -

C Morgenthal t e r , J . H . , e t a1 . , Operat ing C h a r a c t e r i s t i c s of a Podielniak Centr i fugal Ex t r ac to r . TID-5463, Massachusetts I n s t . of Tech., Oak Ridge, TN, August 25, 1951.

Morrison, G. H . and H. F re i se r , "Extraction." Anal. Chem. , - 34:64R-81R, April 1962.

Mottel, W. S., Mixer-Settler D velopment--Use of Shrouded Paddle. DP-130, . E. I . du Pont de Nemours & Co., Inc. , August 1955.

Mottel, W. J . and T. J . Colven, Mixing Efficiency i n Mixer-Settlers--The Effect of Flow and Paddle Variables. DP-254, E. I . du Pont de Nemours & Co., Inc. , December 1957.

Mumford, C. J . , "Liquid Extraction i n a Continuous Agitated Horizontal Con- t ac to r . " ISEC171, - 1:260.

Mumford, C. J . and A. A. A. Hemirig, "The Effect of Wetting Charac te r i s t i c s Upon the Performance of a Rotating Disc Contactor." ISEC174, 2:1591. - Murphy, N . F . , e t . a1 . , Mass Transfer i n a Horizontal Liquid-Liquid Extraction Tube. Virginia Polytechnic I n s t i t u t e , 1954.

Murty, R. K. and C. V . Rao, "Perforated-Plate Liquid-Liquid Extraction Towers: Effect of Spacing i n the Methyl Isobutyl Ketone-butyrie Acid Water System." Ind. & Eng. Chem. Process Design, - 7:166-172, April 1968.

Nelson, W. L . , "Operating Cost: Furfural o r Phenol Extraction." Oil & Gas J . , 59:138, June 12, 1961. - "New Extraction Ci rcu i t Cuts Solvent Use 95 Percent: Centrifugal Contactors." Chem. Eng., 66-:98, March 23, 1959.

Newman, J . S., The Proper t ies of a Resonant Air Cavity and Transfer Line in a Piston-Pul s e r System. Oak Ridge National Laboratory, Oak Ridge, TN, May 6, 1960.

Nichols, G. S . , Turbine Contactor f o r Solvent Extraction. E . I . du Pont de Nemours & Co., Inc . , December 1958.

Nicholson, G . A * , Purex Phase I1 Flowsheet--HA Column Studies . General E l ec t r i c Co., Hanford Atomic Products Operation, Richland, WA. May 31, 1957.

Nicholson, G. A . , Purex Pulse Column Studies with Hydrocarbon Diluent. HW-40550, - 1 :79, Ju ly 24, 1956.

Nicholson, G . A . , Purex Pulse Column Studies w i t h Hydrocarbon Diluent. HW-40550, - 2:109, July 24, 1956.

Null, H . R. and H. F. Johnson, "Drop Formation i n Liquid-Liquid Systems from a .

Single Nozzles." AIChEJ, - 4:273-281, 1958.

Oberg, A. G. and S. C . Jones, "Liquid-Liquid Extraction." Chem. Eng., 70: 11 9-1 34, July 1963. -

O'Br ien, D. C., An O r i f i c e P l a t e Pulse Column f o r L i q u i d - L i q u i d E x t r a c t i o n . Thesis, Massachusetts I n s t . o f Tech., Oak Ridge, TN, August 23, 1954.

Ochsenfeld, W. and S. Krawczynski, " M i x e r - S e t t l e r f o r E x t r a c t i o n Experiments." Kerntechni k, - 5:218-221, May 1963.

Oldshue, J. Y., e t a l . , "M ix ing E f f e c t s i n a M u l t i s t a g e Mixer Column." ISEC'74, 1:1651.

Oldshue, J. Y., "M i x i ng Equipment i n L i q u i d - L i q u i d Ex t rac t i on . " So lven t E x t r . Rev. 1, - 2:185-213, 1971.

Oldshue, J. Y. and J. H. Rushton, Chem. Enq. Progr., %:297, 1952.

Olney, R. B., "D rop le t C h a r a c t e r i s t i c s i n a Counte rcur ren t Contactor . " AIChEJy l O ( 6 ) ~827-835, 1964.

Olney, R. B., " L i q u i d - L i q u i d E x t r a c t i o n . " AIChEJ, lO(6):89-139, 1964.

Olney, R. B. and R. S. M i l l e r , " L i q u i d - L i q u i d E x t r a c t i o n i n Modern Chemical Engineer ing." Phys ica l Operat ions, 1:89-139, 1963.

Olson, E. Hay e t a l . , E x t r a c t i o n Equipment and Sampling Technique Used i n Semi-Continuous S i l ve r -Uran ium E x t r a c t i o n S tud ies . Arnes Laboratory , Iowa S t a t e U n i v e r s i t y , Ames, IAy J u l y 1959.

Orth, D. A.9 Eva lua t i on o f C e n t r i f u g a l Contactors . E. I. du Pont de Nemours & Co., Aiken, SC, June 1969.

O s t r o v s k i i , M. V., e t a l . , "Spontaneous Sur face Convect ion Dur ing E x t r a c t i o n i n a L i q u i d - L i q u i d System. " Zh. P r i k l . Khim. , - 41 (4);803-810, 1968.

Overcashier, R., e t a l . , AIChEJ, - 2:529, 1956.

Pang, K. H. and A. I. Johnson, "Opt imal Operat ing P o l i c y f o r a L i q u i d - L i q u i d E x t r a c t i o n Column." Can. J. Chem. Eng 0 9 - 49:398-406, June 1971.

Pang, K. H. and A. I. Johnson, "Mathematical Model ing of a M o d i f i e d Scheibel L i q u i d - L i q u i d E x t r a c t i o n Column i n t h e Frequency Domain." Can. J. Chem. Enq., 49:837-843, August 1971. -

Pang, K. H. and A. I. Johnson, "Minimum Time Operat ing P o l i c y For a L i q u i d - L i q u i d E x t r a c t i o n Column." Can. J . Chem. Eng., e :529-539, August 1971.

Parad iss is , G. N. and P. V . Maney, " A p p l i c a t i o n o f U l t r a s o n i c s i n E x t r a c t i o n o f Ergo t A1 ka lo i ds . " Manuf. Chem. , %:62-63, October 1965.

P a r r e t t , 0. W., The Dete rmina t ion o f Excessive E m u l s i f i c a t i o n by Coalescence Behavior Measurements. U.S. Atomic Energy Commission, ID014886, 25 pp. November 25, 1959.

Peel, D. and G. C. Coggan, "The Transurface Contactor: A New L i q u i d - L i q u i d Ex t rac to r . " ISEC ' 71 , - 2: 1251.

Peterson, H. C., " P r e d i c t i o n of Ideal-Stage Requirements i n Complex L i q u i d - L i q u i d E x t r a c t i o n Systems." AIChEJ, - 2:38-41, 1956.

Phi loon, W. C. and J. T. Krieg, De-entrainment of Organic E x t r a c t by E lec t ro - s t a t i c P r e c i p i t a t i o n . M a l l i n c k r o d t Chemical Works, November 6, 1959.

P ie te rs , W. T., Contact Apparatus w i t h Rota t ing Discs. U.S. Patent 2,729,544, U.S. Patent O f f i ce , Washington, DC, January 3, 1956.

P i key F. P. and E. E. Erickson, The Flooding Capacity o f a Pulse Column on t h e Benzene-Water System. ORO-141, Nor th Caro l ina S ta te Col lege, A p r i l 18, 1954.

Pike, F. P. and E. E. Erickson, The Development o f a Theory o f Pulse Column Flooding Behavior. 0R0-288, Nor th Caro l ina S t a t e College, A p r i l 20, 1955.

Pike, F. P., e t a l . , The Performance o f Contactors f o r L i q u i d - L i q u i d Ex t rac- t i o n Progress Report No. 3 (P re l im ina ry ) : The A p p l i c a t i o n o f S t a t i s t i c a l Procedures t o a Study o f t h e Flooding Capacity o f a Pulse Column. ORO-140, North Caro l i na S t a t e College, February 1954.

P i l g r i m , R. F. and F. J. Ke l l y , "Development o f an Empi r ica l Mathematical ~ o d e l f o r a Pulse s ieve-p la te- E x t r a c t i o n Column. " can. , Mines B r . , Tech. Bu l l . . 164:27. 1972.

" P i l o t So lvent E x t r a c t i o n U n i t Marked." Chem. & Eng. N., - 38:50, August 29, 1960.

P in to , A. F., "Improved Form o f Soxh le t Ex t rac to r . " Am. O i l Chem. Soc. J.9 44: 160, February 1 967. -

Pleasance, C. L., "Continuous Ana lys is i n Nuclear Processing: Radiochemical P i l o t P lant . " - - ISAJ, 5:39-42, June 1958.

Plummer, M. A. and G. H. Pouska, "Ty ing Two Ex t rac to rs Together." Hydrocar- bon Process, - 52:91-94, June 1973.

Ponikarov, I. I. and A. M. Nikolaev, "E f f i c i ency Factor as a C r i t e r i o n fo r Comparative Eva lua t ion o f E x t r a c t i o n Equipment." Tr. Kazansk. Khim. Tekhnol. I ns t . , 30:360-364, 1962. - -

Pope, B. J. and N. R. Shah, "An Improved Contactor f o r L i q u i d - L i q u i d Extrac- t i o n . " ISEC'71, - 1 :899.

P r a t t , H. R. C., " A x i a l Dispers ion i n D i f f e r e n t i a l E x t r a c t i o n Columns w i t h P e r f e c t Mass Trans fer . " Ind. & Eng. Chem. Fund., - 10:170-174, February 1971.

P r a t t , H . R. C . and A. S. White, " I n t e r f a c i a l Area i n Packed Liquid Ext rac t ion Columns." Chem. & Ind., pp. 382-389, 9952.

Prochazka, 9. and I . Lanclav, "Ex t r ac t i on with Back-Mixing." Chem. & Process Eng., - 74:51-55, January 1967.

Quinn, J . A. and D. B. S ig loh , "Phase Invers ion i n t h e Mixing of Immiscible Liquids. " Can. J . Chem. Engr. , 9: 15, 1963.

Rahn, R. W. and M. Smutz, "Development of a Laboratory Sca l e Continuous Mu1 t i s t a g e Ext rac tor . " Ind. & Chem. Process Design, 8:289-293, J u l y 1968.

Redon, A. , e t a l . , Cons idera t ions on the Determination o f t h e Daily Ex t r ac t i on Capacity and t h e Workinq Capaci ty of t h e Col umns o of the Eurochemic P l an t . NP-7682. E u r o ~ e a n Com~anv f o r t h e Chemical Processinq of I r r a d i a t e d Fue ls , ~ o l , el gium, Ja&ary 9, 1959.

-

Regnaut, P . , e t a l . , "The Processing of I r r a d i a t e d Uranium i n t h e Commissariat a l t E n e r g i e Atomique, Fontenay-aux-Roses P i l o t P l an t . " Proceedings o f t h e Second I n t e r n a t i o n a l Conference on t h e Peaceful Uses of Atomic Energy, Geneva 1958, - 17:90-91, United Nations, New York, N Y , 1959.

Reinhardt , H . and J . Rydberg, "Solvent Ext rac t ion S tud ie s by t h e AKUFVE Method. 11. A New Cent r i fuge f o r Absolute Phase Separa t ion ." Acta. Chem. Scand. , - 23 (8) : 2773-2780, 1969.

Reman, G. H . , "Solvent Ext rac t ion : Ext rac t ion Outside the U.S." Chem. Eng. Prog., - 62~56-61 , September 1966.

Reman, G. H. and J . G. Van d e Vusse, "Rotating-Disk Contactor ." Genie. C h i m . , 74:106-114, 1955. -

Reman, G. H . and J . G. Van de Vusse, "Applying RDC t o Lube Ex t r ac t i on . " Petroleum Ref iner , 3 4 ( 9 ) : 129-1 34, 1955.

Reman, G. H . , Liquid Contact Apparatus. U.S. Pa ten t 2,601,674, U.S. Pa ten t Off ice , Washington, D C , June 24, 1952.

Reman, G. H. and W . J . Pieters, Apparatus f o r Bringing Two o r More Phases i n t o Contact. Dutch Pa t en t 72,682, J u l y 15, 1953.

Reman, G. H. and R. B. Olney, "The R o t a t i n g - ~ i s k Contactor--A New Tool f o r Liquid-Liquid Ext rac t ion ." Chem. Eng. Prog. , a :141-146 , 1955.

Reman, G. H., " A New E f f i c i e n t E x t r a c t i o n Apparatus: The Ro ta t i nq D isk Contactor. " Proceedings o f t h e 3 r d World petro leum Congress, ~ h e - ~ a ~ u e . I I I : 122 . 1951.

Reman, G. Hay " E x t r a c t o r Equipment Outs ide t h e U.S." Chem. Eng. Progr. , 62: 56-61 , September 1966. -

Reports on t h e Progress o f App l ied Chemistry. Soc ie t y o f Chemical I n d u s t r y London, England, - 53, 1986; - 55, 1970; - 57, 1972; - 59, 1974.

"Research and Development on Aqueous Processing. " Reactor Fuel Process, 7(3):167-179, 1964. -

Richardson, G. L., N i t r a t e Cont ro l i n t h e Purex 2HF Stream - P i l o t P l a n t Studies. BNWL-CC-2066, B a t t e l l e , P a c i f i c Northwest Labora tor ies , Richland, WA, A p r i l 27, 1969.

Richardson, G. L., "Crud" Scrubbing w i t h a Purex-Type 2ebra Car t r i dge . HW-63791, Hanford Atomic Products Operat ion, Richland, WAY October 17, 1961.

Richardson, G. L. and A. M. P l a t t , "The Design and Operat ion o f I n d u s t r i a l Scale Pulse Columns f o r Purex Service." Progress i n Nuclear Energy, Ser ies I V Technology, Engineer ing and Safety, HW-SA-2037, Pergamon Press, New York, NY, - 4:279-307, 1961.

Richardson, G. L., Demonstration of Purex Process Condensate Recycle and Other Purex Pulse Column Studies. BNWL-CC-2260, B a t t e l l e , P a c i f i c Northwest Laboratory, Richland, WAY September 26, 1969.

Richardson, G. L., Operat ion o f t h e Purex P l a n t C-Type Columns With Top I n t e r f a c e . HW-40231, December 1 , 1955.

Richardson, G. L., Purex 2D and 2E Column Studies, HW-73452, A p r i l 23, 1962.

Richardson, G. L., The Design and Operat ion o f Purex Process Pulse Columns. HW-SA-2083, February 17, 1961.

Richardson, G. L., Purex Pulse Column Stud ies w i t h Z i r f l e x - D e r i v e d Feeds. BNWL-2186, P a r t 1, Appendix A, B a t t e l l e , P a c i f i c Northwest Labora tor ies , Richland, WAY J u l y 10, 1967.

Richardson, G. L., Purex 1BX-IBS Column Studies, HW-84473, October 12, 1964.

Richardson, G. L. and G. Sege, Purex Process Pulse Column Stud ies Wi th CC14 as D i 1 uent. HW-27171, Se~tember 7, 1954.

Riggs, E. F., Unba f f l ed One-Stage Fenske E x t r a c t o r Recoplex So lvent - E x t r a c t i o n Studies. HW-22938. December 21, 1951.

R i t c e . ~ , G. M . , e t a l . , "Construct ion and Operation of an Experimental Sieve- p l a t e - Pulse Column f o r Sol vent Ext rac t ion of Metal s. " can .' Mines Br. , Inform. C i r c . , 259:22, 1970.

Ri t c e y , G. M . , "Solvent-in-Pulp Processing Using S ieve P l a t e Pulse Columns. ' Chem. Ind., 5: 1294-1 299, 1971.

R i t s cha rd , W. J. and H . Tompa, " Countercurrent Ext rac t ion . 11. Ext rac t ion Research w i t h Mu1 t i s t a g e p l a t e Ex t r ac to r wi th 25 S tages . " Helv. Chim. Acta . , 46:j957-1967, 1963. - Robinson, C. G . , "Development of a Computer Proqram f o r Countercurrent Ooera- t i o n s involving-~i~uid-sol i d - s o l u t e separat ions:" Nat. I n s t . Met., ~ e ~ u b . S. Afr., - 898:21, 1970.

Robinson, C. G . , "Optimizat ion of t h e Design of a Countercurrent Liquid-Liquid Ex t r ac t i on P l a n t Using LIX-64N." Nat. I n s t . Met., Repub. S. Afr., 1085:20, 1970.

Robinson, C. G . and J . C. Paynter , "Proceedings I n t e r n a t i o n a l Solvent Extrac- t i o n Conference." ISEC '71, 2:1416, Proceedinqs of t h e Soc i e ty of Chemical Indus t ry , London, England, 1 971 . Robinson, J . B. and H. T. T u D D ~ ~ , The O ~ e r a t i o n of a Pulse Column f o r Pro-

Rod, V . and T. Misek, "Residence Time D i s t r i b u t i o n of the Dispersed Phase i n Agi ta ted Ext rac t ion Col umn. " ISEC'71, 1: 738.

Rodger, W. A . , e t a l . , " E f f e c t o f F lu id Motion on I n t e r f a c i a l Area of Dispersion." Chem. Eng. Progr . , g :515-520 , 1956.

Roth, B. V . , Development of Cent r i fuga l Ex t r ac to r s f o r the Aqueous Re- processing of Breeder Fuel Elements. Kernforschungsanlage, Karlsruhe, West Germany.

Rouyer, H . , Cont r ibu t ion t o Study of T rans i to ry Regimes i n Mixer -Se t t le rs : Ext rac t ion of Uranium. Commissariat a 1 'Ene rg i e Atomique, Fontenay-aux-Roses, - . . - - - - France, November 1971.

Rouyer, H . 9 e t a l . , "Elements f o r the Design and Operat ional Development o f Pulsed Columns." Bul l . Inform. Sc i . Tech. =:29-34, September 1973.

Rouyer, H. and J . M. Demarthe, I n v e s t i q a t i o n o f Some Nonlinear E f f e c t s i n Ext rac t ion Equipment Using Computer Simulat ion. Commissariat a 1 ' Energie Atomique, Fontenay-aux-Roses, France, Centre d lE tudes Nucleaires , June 1971.

Rouyer, H., e t a1 . , "Proceedings I n t e r n a t i o n a l Sol ven t E x t r a c t i o n Conference. " ISEC' 74, Proceedings o f t h e s o c i e t y o f Chemical I ndus t r y . CEA-CONF-2907, London, 3: 2339, 1974.

Rowden, G. A., e t a1 . , "Proceedings I n t e r n a t i o n a l Sol ven t E x t r a c t i o n Conference. " =

ISEC ' 74, 1: 81 , Proceedings o f t h e Soc ie t y o f Chemical I ndus t r y , London, England, 1974.

Royston, D. and A. Burwel l , Design and Performance o f Pump-Mix and G r a v i t y - Flow M ixe r -Se t t l e r s . AAEC/E-274, A u s t r a l i a n Atomic Energy Commission Research Establ ishment, Lucas Heights, New South Wales, A u s t r a l i a , A p r i l 1973.

Rozen, A. M., e t a l . , C e r t a i n Laws Governing Hydrau l i cs and Mass Transpor t i n Packed Pulse Columns. Gosatomizdat, MOSCOW, 1962.

Rozen, A. M., E f f i c i e n c y o f Pulse Columns ( C o n t r i b u t i o n t o t h e General Theory o f I n t e n s i f i e d Countercurrent E x t r a c t o r s ) . Gosatomizdat, Moscow, 1962.

Rozen, A. M., e t a l . , "Mathematical Modeling o f E x t r a c t i o n Processes f o r Nuclear Fuel Reprocessing. 111. Oxidat ion-Reduct ion S t r i p p i n g Using Ferrous S a l t s . " A t . Energy. (USSR), g ( 6 ) : 367-371, June 1975.

Rubin, B. and H. R. Lehman, Performance o f L i q u i d - L i q u i d E x t r a c t i o n Equip- ment. UCRL-718, U n i v e r s i t y o f C a l i f o r n i a , Rad ia t i on Lab., Berkeley, C A . 3 May 24, 1950.

Ruchy J. Bay L i m i t i n g Flow Rated i n Continuous Countercurrent E x t r a c t i o n Columns. ORNL-96, Oak Ridge Na t i ona l Laboratory, Oak Ridge, TN, J u l y 15, 1948.

Ruehle, A. E. and W. M. Leaders, Research and Development Progress Report . NYO-1352, M a l l i n c k r o d t Chemical Works, St. Louis, M O y January 15, 1958.

Rushton, J. H., "Design Trends i n M ix ing and Mixers." Ind. Eng. Chem., 54: 59-61 . - Rushton, J. H., e t al . , "Power C h a r a c t e r i s t i c s o f M ix ing Impe l le rs . " Chem. Eng. Progr., %:395-467, 1950.

Rushton, J. H. and L. H. Mahony, "Fundamentals o f M ix ing and A g i t a t i o n w i t h Appl ' icat ions t o E x t r a c t i v e Meta l lu rgy . " J. Meta ls 6, A I M E Trans., 200:1199-1206. 1954.

Rushton, J. H., "The Use o f P i l o t - P l a n t M ix ing Data." Chem. Eng. Progr. , 47:485-488. 1951.

Rushton, J. H. and J . Y . Oldshue, "Mix ing: Present Theory and P rac t i ce . " Chem. Eng. Progr., fi:161-168, 267-275, 1953.

Rushton, J. H., Paper 10.4, Presented a t AIChE-IChE Meeting, London, England, 1965.

Ruskan, R. P . , " E f f e c t s o f a S u r f a c t a n t on a Mechanically Agi ta ted Extrac- t i o n Column." Ind. & Enq. Chem. Process Design, - 13:203-208, J u l y 197 . Russe l l , S. H a , Pu lse Amplitude and Frequency Effec ts i n a Pulsed Packed Column. CEI-69, Atomic Energy of Canada Ltd.3 Chalk River P r o j e c t , Chalk River , Ontar io , Apri l 1954.

Russel 1 , S. H . , A Survey of Liquid-Liquid Contact ing Equipment. National Research Council of Canada, Atomic Energy P r o j e c t , Chalk River , Ontar io , February 15, 1952.

Ryle, B. G . , amma ma Density Contols Ext rac t ion Column." Chem. Eng. Progr . , 53: 551 -555, November 1957. - Ryon, A. D a y e t a l . , "Scale-up o f Mixer -Se t t le rs . " Chem. Eng. Progr . , 55(10):70-75, 1959. - Ryon, A. D . , e t a l . , Prevent ion o f S i l i c a S t a b i l i z e d Emulsions by Solvent- Continuous Mixing, i n Chemical Technology Div is ion , Chemical Development Sec t ion C, Monthly Progress Report f o r August 1959. CF-59-8-45, Oak Ridge National Laboratory, Oak Ridge, TN, September 8, 1959.

Ryon, A. D . , e t a l . , Experimental Basis f o r t h e Design o f Mixer -Se t t le rs f o r the Amex Solvent Ex t r ac t i on Process . ORNL-3381, Oak Ridge National Laboratory, Oak Ridge, TN, Apri l 19, 1963.

Ryon, A. D. and R. S. Lowrie, E f f i c i ency and Flow Capacity of Pulsed Columns Used f o r t h e Separa t ion o f Uranium From Thorium by Solvent Ext rac t ion With Di-sec-butyl Phenylphosphonate. Oak Ridge National Laboratory, Oak Ridge, TN, 1965.

Sa to , T., "Ex t r ac t i on o f Uranium (VI) and Thorium from N i t r i c Acid So lu t ions by Tri-n-butyl Phosphate." J . Ap. Chem., - 15:489-495, November 1965.

Sa to , T., "Ex t r ac t i on o f Uranium (VI ) from Hydrochloric Acid So lu t ions by Long Chain Alpha t ic Amines." J . Ap. Chem., - 16:133-136, J u l y 1966.

Sa to , T., "Ex t r ac t i on o f Uranium (VI) and Thorium from Hydrochloric Acid So lu t ions by Tri-n-butyl Phosphate." J . Ap. Chem., l6-:53-57, February, 1966.

Sawinsky, Jay " E f f e c t of Axial Mixing on t h e Separa t ion E f f i c i ency of a coun te rcu r r en t Ex t r ac to r w i t h - c e n t r a l Feed. " Proc. Conf. Appl .- Phys. Chem., Znd, - 2:75-80, 1971.

Sawistowski, H., Recent Advances i n Liquid-Liquid Ex t r ac t i on . C. Hanson, ed., Pergamon Press, Oxford, England, 1971.

Schei be1 , E. G. , " D i f f i c u l t Separat ions by Ex t rac t i on . " Chem. Eng. Progr. , 62: 76-81 , September 1966. -

Scheibel, E. G. and A. E. Karr, "Semicommercial M u l t i s t a g e E x t r a c t i o n Column. Performance C h a r a c t e r i s t i c s . " Ind. Eng. Chem. , 42: 1048-1 057, 1950.

Scheibel, E. G . 9 L i q u i d - L i q u i d E x t r a c t i o n Procedure. U.S. 3,177,196, U.S. Paten t Of f ice, Washington, DC, A p r i l 6, 1965.

Schei be1 , E. G., " F r a c t i o n a t i o n by L i q u i d - L i q u i d Ex t rac t i on . " Chem. Ing. Tech., 27:341-351, 1955. - - Scheibel, E. G., "Performace o f an I n t e r n a l l y B a f f l e d M u l t i s t a g e E x t r a c t i o n Column." AIChEJ, - 2:74, 1956.

Sch ind le r , H. D. and R. E. Treybal , AIChEJ, - 14:790-798, September 1968.

Schlea, C. S., e t a l . , Purex Process Performance w i t h Short-Residence Contactors. DP-809, E. I. du Pont de Nemours & Co., Inc., September 1 963.

Schmieder, H., e t a1 . , Development o f a M i x e r - S e t t l e r f o r t h e E l e c t r o l y t i c Plutonium-Uranium Separat ion i n t h e Purex Process. Reaktortagung, Bonn, 1971.

Schmieder, H., e t a l . , E l e c t r o l y t i c Methods f o r A p p l i c a t i o n i n t h e Purex Process. G e s e l l s h a f t f u e r Kernforschung, Germany, 1974.

Schmieder, H., e t a l . , Improvements i n t h e Purex Process by E l e c t r o l y t i c Methods. Kernforschungszentrum, Karlsruhe, Germany, 1973.

Schmeider, H., Proposed New Design o f L i q u i d - L i q u i d Contactor . C a l i f o r n i a Research and Development Co., Livermore, CAY March 25, 1952.

"Second Look a t U n i t Operat ions; EWxtract ion and Sedimentat ion." Can. Chem. Process, - 44:62-63, Feburary 1960.

Scot t , L. S., e t a l . , "Formation o f I n t e r f a c i a l Area i n Immisc ib le L i q u i d s by O r i f i c e Mixers." AIChEJ, - 4:346-350, 1958.

-.

Sege, G., Summary o f 20-Stage Fensk E x t r a c t o r "Recuplex Resu l ts . HW-22580, October 31. 1951.

Sege, G., E x p l o r a t i o n o f Purex 2A and 2B Packed Column Performance. HW-27335, March 6, 1953.

Sege, G. and F. W. Woodfield, Pu lse Column Var iab les - Solvent Ext rac t ion of Uranyl N i t r a t e with Tr ibu ty l Phosphate i n a 3-Inch Diameter Pulse Column. HW-27365, Apri l 20, 1953.

Sege, G. and F. W. Woodfield, "Pulse Column Variable ." Chem. Enq. Progr . , 50:396-482, 1954. -

Sehmel, A. and A. L. Babb, "Holdup S tud ie s i n a Pulsed-Sieve P l a t e Column." Ind. & Eng. Chem. Process Design, 2:38-42, June 1963.

Sehmel, G. A. and A. L . Babb, "Longitudinal Mixing S t u d i e s i n a Pulsed Extrac- t i o n Column." Ind. & Enq. Chem. Process Design, - 3:210-214, J u l y 1964.

Se id lova , 0 . and T. Misek, "Proceedings I n t e r n a t i o n a l Solvent Ext rac t ion Conference." ISEC174, 3:2365, Proceedings of t h e Soc i e ty of Chemical Indus t ry , London, ~ n g l aKd, 1974.

S e y f r i t , K. V . , Purex 2A Column Capacity S tud ie s . HW-51757, General E l e c t r i c Co., Hanford Atomic Products Operat ion, Richland, WA, J u l y 31, 1957.

Shank, E. M . , Eurochemic Company Assistance--Hanford Atomic Products Operat ion Spent Fuel Processing Technoloqy. Oak Ridge National Laboratory, Oak Ridge, TN, June 23, 1959.

Sheely, H. R . , Ca l cu l a t i on of Liquid-Liquid E q u i l i b r i a f o r Complex Solvent Ext rac t ion Systems. Solvent Ex t r ac t i on Symposium, December 12-15, 1954.

Sheikh, A. R . , e t a l . , Trans. I n s t . Chem. Engrs., - 50:199, 1972.

Shih, C. K. and R . R. K rayb i l l , "Dispersed Phase D i s t r i b u t o r s i n a Packed Countercurrent Liquid-Liquid Ex t r ac t i on Column." Ind. & Eng. Chem. Process Design, - 5:260-264, J u l y 1966.

Shinnar , R. and J . M. Church, "P red i c t i ng P a r t i c l e S i z e i n Agitated Disper- s ions ." Ind. Eng. Chem., - 52:253-256, 1960.

Shinnar , R., Turbulence-Stab i l ized Dispersion-Inf luence of Turbulent Agita- t i o n on Liquid-Liquid Disperaions i n t h e Presence of a P r o t e c t i v e Col lo id . , D i s s e r t a t i o n s Abst. , a :4614-4615, 1960.

Shi ro tsuka , T., e t a l . , "Liquid-Liquid Dispersion i n Concurrent Flow Through an O r i f i c e . " Kagaku Kogaku, - 25:109-113, 1961.

Shtrba, I., Stud ies of Reprocessing of I r r a d i a t e d Fuel . Reports o f t h e Sympo- sium He ld i n Karlovy-Vary, Czechoslovakia, February 26-March 2, 1968.

Shtrobel , V., " L i q u i d Ex t rac t i on . V. Mass Transfer i n a Ro ta t i ng D isk E x t r a c t o r . " Zh. P r i k l . Khim., x ( 1 ) : 50-58, 1969.

Sims, R. P. A. and G. A. Adams, "Improved L i q u i d - L i q u i d E x t r a c t o r . " Am. O i l Chem. Soc. J., - 35:139-140, March 1958.

S i t t e l , C. N.9 Jr. and G . T. F isher , "Trans ien t Response o f a D i s t i l l a t i o n Column P la te . 111. Model Eva lua t i on from Concentrat ion Pulse Data on a P l a t e f o r t h e Benzene-Carbon T e t r a c h l o r i d e System." Separ. Sc i . , - 8(4 ) : 457-471 , 1973.

Skel land, A. H. P. and W. L. Conger, "Rate Approach t o Design o f Pe r fo ra ted P l a t e E x t r a c t i o n Columns." Ind. & Enq. Chem. Process Design, - 12:488-454, October 1973.

Skel land, A. H. P. and C. L. Caenepeel, "E f fec ts of Sur face A c t i v e Agents on Mass Transfer Dur ing D r o p l e t Formation, Fa1 1 and Coalesence. " AIChEJ, 18:1154-1163, November 1972. -

S l a t e r , M. J., e t a l . , "Proceedings I n t e r n a t i o n a l So lvent E x t r a c t i o n Confer- ence." ISEC '74, 1:107, Proceedings o f t h e Soc ie t y o f Chemical I n d u s t r y . London, Engl and, lg74.

S le i che r , C. A * , Jr . , " A x i a l M ix ing and E x t r a c t i o n E f f i c i e n c y . " AIChEJ, 5:145-149, June 1959. -

Sle i che r , C. A., Jr., "Entrainment and E x t r a c t i o n E f f i c i e n c y o f M ixer S e t t l e r s . " AIChEJ, - 6:529-530, September 1960.

Smith, A. R e , e t a l . , "Coalescence o f Drops i n L i q u i d - L i q u i d E x t r a c t i o n Columns." Can. J. Chem. Eng., fi:150-157, August 1963.

Smith, B. D. and W. K. B r i nk ley , "Rigorous S o l u t i o n o f Mult icomponent M u l t i - s tage E x t r a c t i o n Problems." AIChEJ, - 6:451-454, September 1960.

Smith, B. D. and W. K. B r i nk ley , "General Short-Cut Equat ion f o r E q u i l i b r i u m Stage Processes." AIChEJ, - 6:446-450, September 1960. . - Smith, P. E.9 e t a l . , "Equipment Design--Process and Mechanical Considera- t i o n s , 3." E x t r a c t o r s i n Reactor Handbook 11, Fuel Reprocessing, 2nd ed., I n t e r s c i e n c e Pub l ishers , Inc., New York, NY, pp. 563-592, 1961.

Smith, P. E., P.urex HA Column Study. E f f e c t o f Sodium DiChromate. May 11, 1959.

Smoot, L. D. and A . L . Babb, "Mass Transfer S t u d i e s i n a Pulsed Ext rac t ion Column." Ind. & Eng. Chem. Fundamentals, - 1:93-103, May 1962.

Smoot, L. D m , e t a l . , "Flooding C h a r a c t e r i s t i c s and S e ~ a r a t i o n E f f i c i e n c i e s of Pulsed S ieve P l a t e ~ x t r a c t i o n Columns." Ind. Eng. hem., - 51 : 1005-1010, 1959.

Smutz, M . , P r ed i c t i on of Continuous Ex t r ac to r Performance from Simulated Ext rac t ion Column Data. Ames Laboratory, Ames, IA, September 1957.

Sobot ik , R. H . and D. M . Himmel blau, "Ef f ec t of P l a t e Wettins C h a r a c t e r i s t i c s of Pulse Column Ex t r ac t i on ~ f f i c i e n c ~ . " AIChEJ, - 6: 61 9-624, December 1960. ( ISC-900)

"Solvent Ext rac t ion and Ion Exchange Symposium. Bradford, England, December 2, Abs t r ac t of Papers ." Chem. & Ind . , pp. 478-481, May 1 , 1971.

Sood, R. K., e t a1 . , Performance Tes t s of Deaerator of 1 -Mgd C l a i r Engl e Desa l t ing P l an t . ORNL-TM-2491, Oak Ridge National Laboratory, Oak Ridge, TN, September 1969.

Spaay, N . M . , e t a l . , "Proceedings I n t e r n a t i o n a l Solvent Ext rac t ion Conference." ISEC171, - 1:281, Proceedings of the Soc ie ty of Chemical Indus t ry , London, 1974.

Spence, R . and R. J . W . S t r e e t o n , "Counter-current Liquid-Liquid Extrac- t i o n i n Rotary Annul us Columns. " Chem. Process Eng., s : 597 -610 , October 1 968.

Spence, R. and R. J . W . S t r e e t o n , Counter-Current Liquid-Liquid Ext rac t ion i n Annul us Columns w i t h Shearing Motion. AERE-R-4091, United Kingdom Atomic Energy Author i ty . Research Group. Atomic Energy Research Establ ishment , Harwel 1 , Berks, England, September 22, 1952.

S r a i e r , V . , "Counter-Current Ex t r ac t i on i n a Laboratory Mixer -Se t t le r . 111. The D i s t r i b u t i o n of Uranyl N i t r a t e and N i t r i c Acid i n t h e Ext rac t ion Appa- r a t u s by Tr ibu ty lphosphate i n t h e Purex Process ." Jad. Energ., a :336 -341 , September 1965.

S r a i e r , V . and S. Michalek, Hydrodynamic Experiments w i t h Water-Nitr ic Acid-Uranyl Ni t r a t e - 3 0 Percent Tr i butyl Phosphate System i n Horizontal Pulsed Ex t r ac to r . UIV-1665, Ceskoslovenska Akademie Ved, Rez., Ustav Jaderneho Vyzkumu, J u l y 1967.

S r in ivasan , N . , e t a l , Development o f Air Pulsed Mixer S e t t l e r Equipments f o r Solvent Ex t r ac t i on S tud ie s . BARC-672, Bhabha Atomic Research Centre , Bombay, Ind i a , 1973.

Stanew, S. and V . Kamedulski, "Continuous Countercur ren t Ex t r ac to r . " Ind. Chem., 37:303, June 1961. -- - "Steady-Sta te D i s t r i b u t i o n Machine Introduced; Programable True Counter- c u r r e n t Liquid-Liquid E x t r a c t o r Shows Promise a s V e r s a t i l e Research Tool." Chem. & Eng. N . 9 4J:79, October 29, 1962.

S t e i n e r , L. and S. Har t land , "Ca lcu l a t i on of Mass T rans fe r C o e f f i c i e n t s i n Ex t r ac t i on Column Under Non-Ideal-Flow Condi t ions ." ISEC'74, - 3:2289.

Stevenson, C. E. and 0. M . Paige, "Research and Development on Aqueous Process ing ." Reactor Fuel Process . Techno]., - 11:144-148, 1968.

Stevenson, C. E . 3 "Solvent Ex t r ac t i on Processes f o r Enriched Uranium." TID-7534, Symposium on t h e Reprocessing of I r r a d i a t e d Fue ls , B rus se l s , Belgium, May 20-25, 1957.

Stevenson, R . L. and J . G . Bradley, TBP P l a n t Solvent -Ext rac t ion Pulse Columns. . HW-19170, General E l e c t r i c Co. , Richland, MA, November 6 , 1951.

S tonner , H . M . and F. Wohler, "AIChE Symposium S e r i e s No. 42." Proceedings o f t h e I n s t . Chem. Engr. , 1975.

S t r and , C. P . , e t a l . , "Fundamental Aspects of Rotat ing Disk Contactor Performance." AIChEJ, - 8:252-261, 1962.

S t raughn, J . L. and W . B . Tarp ley , I n v e s t i g a t i o n s t o Determine the F e a s i b i l i t y o f U l t r a s o n i c Liquid-Liquid E x t r a c t i o n , Aeropro jec t s , Inc. , February 1957.

Subbarao, 6. V . and C. Venkatarao, "Spray Tower Performance. Ex t r ac t i on of P r o ~ i o m i o Acid from Dispersed Toluene t o Water: E f f e c t of Number o f ~ o z z l e s and Flow Rates on Mass-Transfer C o e f f i c i e n t . " J . Appl . Chem. , 1 6 ( 7 ) :218220, 1966. - Subhasavasdikul , S . , e t a l . , " I n f l u e n c e of a Rota t ing S t i r r e r on t h e Operat ion o f a Pu l se Ex t r ac t i on Column." Can. J . Chem. Eng - 9 - 49:88-94, 1971.

Swi f t , W . H e y Back-Mixing i n Pulse Columns wi th P a r t i c u l a r Reference t o Scale-up. HW-28867, J u l y 20, 1953.

Swi f t , W . H . , Limit ing Flow Capaci ty i n Solvent Ex t r ac t i on Pu l se Columns.' P a r t 1: The E f f e c t o f Pu l se and C a r t r i d g e Geomety Var iab le . HW-33953, Hanford Atomic Products Operat ion, November 30, 1954.

Swift , W. H . and L . L . Burger, Backmixing In Pulse Columns, 11. Experimental Values and E f f e c t of Several Var iab les . HW-29010, Hanford Atomic Products Operation, August 11 , 1953.

Ten Brink, G. and A. Simons, Proceedings I n t e r n a t i o n a l Symposium, "Solvent Ext rac t ion i n Metal 1 u rq i ca l Processes . " Technolosisch I n s t i t u t . K. VIV, Antwerp, p. 59, 1572.

-

Terukatsu, M. and T. Vermeulen, "Longi tudinal Dispersion i n Two-Phase Continuous-Flow Operat ions. " Ind. Eng. Chem. Fundamentals , - 2: 11 3-1 26, 1963.

Thomas, W. J.9 "Performance of Rota t ing Disk Contactor Using t h e System ccly-HC2H302-H20. I' J . Ap. Chem. , =:261-273, September 1970.

Thornton, J . D m , "Liquid-Liquid Ext rac t ion . P a r t XIII : The E f f e c t o f Pulsed Wave Form and P l a t e Geomety on t h e Performance and Throughput of a Pulsed Column." Trans. I n s t . Chem. Eng., 2 :316-330 , 1957.

Thorton, J . D . , Liquid-Liquid Ex t r ac t i on Columns, U . S. Pa t en t 2,818,324, U.S. P a t e n t Of f i ce , Washington, DC, December 31, 1957.

Thornton, J . D . 9 "Drople t Behavior and Mass T rans fe r Rates i n Liquid-Liquid Ex t r ac t i on Operat ions. Ind. Chem. , - 39:632, 1963.

Thornton, J . D . , "Pulsed P l a t e Liquid-Liquid Ex t r ac t i on Columns. " Brit. Chem. Eng., - 3:247-251, 1958.

Thornton, J . D . , "Mechanical Contactors f o r Liquid-Liquid Ext rac t ion ." Nuclear Eng., 1: 156-1 60, 1956.

Thornton, J . D . , The Horizontal Air-Pulsed Column--A New Liquid-Liquid Contac- t o r f o r Radioact ive Process i np. Uni t ed Kingdom Atomic Energy Authori ty . Research Group. Atomic Energy Research Establ ishment , Harwell , Berks, England, January 1958.

Thornton, J . D . , "Fac to r s Af fec t ing t h e Performance of Liquid-Liquid Ex t r ac t i on Equipment." Chem. & Ind., p. 293, February 13, 1965.

Thornton, J . D. and B. A. Bouyut io t i s , "Liquid Ext rac t ion Operat ions i n S t i r r e d Vessels ." Ind. Chem., - 39:298-301, June 1963.

Thorton, J . D . 9 Chem. Eng. & Fuel Sc ience a t Newcastle upon Tyne, 2:25, 1966.

Thornton, J . D . , "Recent Developments i n Pulsed-Column Techniques." Chem. Eng. Progr. Symp. Ser . 50, - 13:39-52, 1954.

Thornton, J . D. and H. R . C. P r a t t , "Flooding Rates and Mass Transfer Data f o r Rotary Annular Col umns. " Trans. I n s t . Chem. Engrs. , =:289-306, 1953.

Thornton, J . D . , "Improved Wetted-Wall F rac t iona t ing Column." Nature, - 166: 484, 1950.

Thornton, J . D . , "Spray Liquid-Liquid Ex t r ac t i on Col umns : P r e d i c t i o n of Limit ing Holdup and Flooding Rates." Chem. Eng. S c i . , 2:201-208, 1956.

Thomas, W . J . and P . K. J . Weng, " O s c i l l a t i n g B a f f l e Column F i t t e d wi th S t a t o r Rings." J . Ap. Chem., - 20:21-29, January; 48-57, February 1970.

Thwaites , J . M . 3 "Pulsed Columns f o r Liquid-Liquid Ex t r ac t i on and Chemical React ion." Dechema. Monograph. , - 55(955-975): 241-250, 1964.

Todd, D. B a y "Cent r i fuga l Ex t r ac t i on o f Waste Dyes." Chem. Eng. P rog r . , 67:60-62, September 1971. -

Todd, D. B. and G . R . Davies, "Proceedings I n t e r n a t i o n a l Solvent Ex t r ac t i on Conference." ISEC174, 3:2380, Proceedings of t h e Soc i e ty of Chemical Indus- try, London, England, 1374.

Todd, D. B . , "Rat ing Chart Helps Choose the Best E x t r a c t o r . " Chem. Eng., 69:156, J u l y 9, 1962. -

Todd, D. El., "Improving Performance of Cent r i fuga l E x t r a c t o r s . " Chem. Eng. Progr . , E : 1 5 2 , J u l y 24, 1972.

Todd, D. B. and W. J . Podbie ln iak , "Advances i n Cent r i fuga l Ex t r ac t i on . " Chem. Eng. Progr . , a : 6 9 - 7 3 , May 1965.

Treyba l , R. E . , "Uni t Operat ions i n Chemical Engineering: Liquid Ex t r ac t i on . " Ind. & Eng. Chem., - 50:463-473, March 1958.

Treyba l , R. E . , "Liquid Ex t r ac to r Performance." Chem. Eng. Progr . , - 62:67-75, September 1 966.

Treyba l , R . E . , "Es t imat ion o f the Stage E f f i c i ency of Simple, Agi ta ted Vesse ls Used i n Mixer -Se t t le r Ex t r ac to r s . " AIChEJ, - 4:202-207, 1958.

Treybal , R . E . , "Liquid Ex t r ac to r Performance. " Chem. Eng. Progr . , - 6 2 ( a ) :67, 1966.

Treybal , R . E . , " V e r s a t i l e , New Liquid E x t r a c t o r . " Chem. Eng. P rog r . , g ( 5 ) : 77, 1964.

Treybal , R. E . , "Uni t Opera t ions Review: Liquid Ex t r ac t i on . " Ind. & Eng. Chem. , 52:262-266, March 1960. - -

I

Treybal , R. E . , Liquid Ex t r ac to r . U.S. Pa t en t 3,325,255, U.S. P a t e n t Of f i ce , Washington, D C , June 13, 1967.

Treyba l , R. E . , Liquid Ex t r ac t i on , 2nd ed . , McGraw - Hi1 1 , New York, N Y , 1963.

Treybal, R. E., "Mechanical ly Aided L i q u i d Ex t rac t ion . " I n : Advances i n Chemical Engineering, 1~289-329, Academic Press, Inc., New York, NY, 1956.

Treybal , R. E. , "Stage E f f i c i e n c i e s o f L i q u i d E x t r a c t i o n Col umns. " Ind. Eng. Chem. , 47~2435-2436, 1955. - -

Treybal , R. E., L i qu id -L iqu id E x t r a c t i o n Apparatus. B r i t i s h Patent 1,044,200, September 28, 1966.

Treybal, R. E., "Economic Design o f M ixe r -Se t t l e r Ex t rac tors . " AIChEJ, 5 : 474-482, 1959. -

Treybal, R. E., " U n i t Operations Review: L i q u i d Ex t rac t ion . " Ind. & Eng. Chem. , 53: 161 -1 65, February 1961.

Treybal, R. E., " S t i r r e d Tanks and Mixers f o r L i q u i d Ex t rac t ion . " Ind. & Eng. Chem., - 53:597-606, August 1961.

Treybal , R. E. , " L i q u i d E x t r a c t i o n Techniques and Prac t ice . " Ind. Eng. Chem, 54~55-60, 62-63, 1962. - Treybal, R. E., Mass Trans fer Operations, 2nd ed., McGraw-Hill Book Company, New York, NY, 1968.

Treybal, R. E., Ind. Eng. Chem. Fundamentals, 3:185, 1964.

Treybal , R. E., " U n i t Operations i n Chemical Engineering: L i q u i d Ex t rac t i on . " Ind. & Eng. Chern., 2:378-388, March 1959.

Troutman, P. H. and J. A. Consig l io , S imulat ion o f a Solvent E x t r a c t i o n Pul sed Col umn. TID-12472, General E l e c t r i c Co. , General Engineering Laboratory, Schenectady, NY, October 1, 1958.

Van Antwerpen, F. J., "Mass Transfer--Transport Proper t ies . " Chem. Eng. Progr., 51, 1955.

Vanderveen, J. H., "Coalescence and Dispers ion Rates i n Ag i ta ted L iqu id -L iqu id Systems." U. S. A t . Energy Comm., 1960.

Van Geel, J., e t a l . , "Chemical Aspects o f Solvent E x t r a c t i o n on P lan t Scale a t Eurochemiec." Proceedings o f t he I n t e r n a t i o n a l Solvent Ex t rac t i on Con- ference. Vol . I and I I. , London, England, 1971.

Varga, L. P., Eva luat ion o f t h e Chain-Driven 1/4-Inch M in ia tu re Mixer S e t t l e r - Rucplex Equi 1 i b r i um Data. February 19, 1952.

. Vashist, P. N. and R. B. Beckrnann, "L iqu id -L iqu id Ex t rac t i on : Annual Review." Ind. & Eng. Chern., - 60~43-51, November 1968.

Vashis t , P. N. and R. B. Beckmann, " L i q u i d - L i q u i d E x t r a c t i o n : Annual Review. " Ind. & Eng. Chem., - 59:71-79, November 1967.

Vaughen, V. C., e t al . , E f f i c i e n c y o f a Three Inch H igg ins Column. Massachusetts - - I n s t . o f Tech., Oak Ridge, TN, December 20, 1956,

Vedaiyan, S., e t a l . , "Some Performance C h a r a c t e r i s t i c s o f Spray Columns." AIChEJ, - 18: 161 -1 68, January 1972.

Venkataraman, G. and G. S. Laddha, " L i m i t i n g V e l o c i t i e s , Holdup, and Pressure . Drop a t F lood ing i n Packed E x t r a c t i o n Columns." AIChEJ, - 6:355-358, September 1960.

Vermeulen, T., e t a l . , " I n t e r f a c i a l Area i n L i q u i d - L i q u i d and Gas-Liquid A g i t a t i o n . " Chem. Eng. Progr., - 51 (2):85F-94F, 1955.

Vermeulen, T., " I n d u s t r i a l A p p l i c a t i o n s of Modern E x t r a c t i o n Processes." Rev. U n i v e r s e l l e Mines, - 11:183-189, 1955.

Vermeulen, T., e t a l . , " A x i a l D i spe rs ion i n E x t r a c t i o n Columns." Chem. Eng. Progr., - 6:95-102, September 1966.

Vermeulen, T. and D. R. Kahn, Jet-Mixed L i q u i d - L i q u i d E x t r a c t i o n Column. U.S. Pa ten t 3,574,558, U.S. Paten t O f f i c e , Washington, DC, A p r i l 13, 1971.

Vermijs, H. J. A. and H. Kramers, " L i q u i d - L i q u i d E x t r a c t i o n i n a Ro ta t i ng - D isk Contactor." Chem. Eng. Sci., - 3:55-64, 1954.

Vi jayan, S. and A. 6. Ponter, "Coalescence i n a Laboratory Continuous Mixer- S e t t l e r U n i t : Con t r i bu t i ons o f Drop-Drop and Drop I n t e r f a c e Coalescence Rates on t h e Separat ion Process." ISEC'74, - 1:591

V i t a l i , S. D., "Continuous Countercurrent E x t r a c t i o n i n a L i q u i d - L i q u i d Sys- tem: A p p l i c a t i o n t o t h e E x t r a c t i o n o f V i tamin A f rom Shark-L iver O i l . " Univ. Nacl. Eva Peron., - 26:85-92, 1951.

Warner, B. F., e t a l . , A Review of t h e S u i t a b i l i t y o f So lvent E x t r a c t i o n f o r t h e Reprocessing o f Fas t Reactor Fuels. BNWL 178(W).

Warwick, G. C. I., " L i q u i d - L i q u i d Contac t ing Equipment: B r i e f Review." Chem. & Ind., pp. 403-408, May 5, 197'3.

Warwick, G. C. I. and J.B. Schuffham, "Design o f M i x e r - S e t t l e r s f o r M e t a l l u r g i - c a l Dut ies." Ingen icursb lad , - 41 (1 5-16): 442-449, 1972.

Warwick, G. C. I., e t a l . , "Proceedings I n t e r n a t i o n a l So lvent E x t r a c t i o n Conference." ISEC'71, 2:1373, Soc ie ty o f Chemical I ndus t r y , London, England, I

- 1971.

Warwick, G. C. I . and J . B. Scuffham, "Solvent Extraction i n Metallurgical Processes." Proceedings Internat ional Symposium, p. 36, Technologic I n s t i - t u t e K.VIV, Antwerp, 1972.

Watjen, J . W . and R. M. Hubbard, "Dynamic Behavior of a Pulsed-Plate Extrac- t ion Column." APChEJ, 93614-619, September 1963.

Watrous, R. A. and R. D. Genham, 1A Column Specific Gravity Control Analysis By Analog Computer. General E l ec t r i c Co., Hanford Atomic Products Operation, R i chl and, WAY October 1964.

Watson, J . S. and L . E. McNeese, "Hydrodynamic Behavior of Packed Liquid- Liquid Extraction Columns w i t h ~l uids of- Different Densities. " ISEC '74 2:1371. -

Watson, J . S. and H. D. Cochran, "Simple Method f o r Estimating the Effect of Axial Back Mi xi ng on Countercurrent Col umn Performance. " Ind. & Eng. Chem. Process Design, - 10:83-85, January 1971.

Webb, R. P . , e t a l . , Application of Pulse Column t o Recovery of Uranium in Waste Solutions. KT-79, Massachusetts Ins t . of Tech., Oak Ridge, TN, June 28, 1950.

Webster, D. S., e t a l . , Flow Character is t ics of a Circular Weir i n a Centrifu- gal Field. E . I . du Ponts de Nemours & Co., Inc., June 1961.

Webster, D. S . , Mixer S e t t l e r Development--Characteristics of the Pump-Mix Impeller. DP-137, E. I . du Pont de Nemours & Co., Inc. , October 1955.

Webster, D. S., e t a l . , Performance of Centrifugal Mixer-Settler i n Reprocess- ing Nuclear Fuel. E . I . du Pont de Nemours & Co., Inc. , Aiken, SC.

Webster, D. S., e t a l . , Hydraulic Performance of a 5-Inch Centrifuqal Con- t ac to r . DP-370. E . I . du Pont de Nemours & Co., Inc. , August 1962.

Weech, M. E . , e t a l . , Direct Air Pulsing of Extraction Columns i n Chemical Processing Technology Quarterly Proqress Report. January-March 1961, Phil 1 ips Petroleum Company, August 18, 1961.

Weech, M . E . and B. E. Knight, "Design of Air Pulsers f o r Pulse Column Application." Ind. & Eng. Chem. Process Desiqn, - 7:156, January 1968.

Wellek, R. M . , e t a l . , "Liquid Extraction Column w i t h Reciprocated Wire Mesh Packing." Ind. & Eng. Chem. Process Desiqn, - 8:515-527, October 1969.

Wermer, A. E., "Continuous Liquid-Liquid Ex t r ac to r . " Anal. Chem., 34:1674-1676, - November 1962.

Whatley, M. E. , Mu1 t i s t a g e Mixer -Se t t le r Arrangement f o r Liquid-Liquid Extrac- t i o n . U.S. P a t e n t 2,754,179, U.S. P a t e n t Of f i ce , Washington, D C , J u l y 10 , 1956.

Whatley, M. E. and W . M . Woodsy Liquid Cyclone Contactor . U.S. P a t e n t 3,052,361, U.S. P a t e n t Off ice , Washington, DC, September 4 , 1962.

Whatley, M. E. and G. L. Br idger , "Solvent Ex t r ac t i on o f So lu t ions Containing Rare Ea r th s . " U . S. A t . Energy Comm., OSC-115, 1950.

Whatley, M. E . , e t a1 . , P u r i f i c a t i o n of Thorium by Solvent Ex t r ac t i on . Iowa S t a t e Col lege , J u l y 1956.

Whatley, M. E . and W . M. Woods, The Performance of an Advanced Experimental Stack-Clone Contac tor : A High Performance Solvent Ex t r ac t i on Machine w i t h P o t e n t i a l f o r Appl ica t ion t o Very Hiqh Radioac t ive S o l u t i o n s . Oak Ridge National Laboratory, Oak Ridge, TN, April 1964.

Whewell, R . W . , e t a l . , J . Inorg. Nucl. Chem., - 37:2303, 1975.

Whitten, J . L . , Bellows Type Resin Column Evaluation--0RNL Metal Recovery P l a n t . Oak Ridge National Laboratory, Oak Ridge, TN, August 12, 1958.

Wicks, C. E . and R . B . Beckman, "Dispersed-Phase Holdup i n Packed Countercur ren t Liquid-Liquid Ex t r ac t i on Columns." Solvent Ex t r ac t i on Symposium, December 12-15, 1954.

W i j f f e l s , J . B. and K. Rietema, "Axial Mixing and C l a s s i f i c a t i o n Phenomena i n Liquid-Liquid F lu id Beds." ISEC'71, 1_:711.

Wilburn, N . P . , "Mathematical Determination of Concentrat ion P r o f i l e s i n Two- Phase ~ o n t i n u o u s Countercur ren t Ex t r ac to r . " Ind. & E n q . Chem. Fundamental s , 3:2158-2162, October 1969. -

Wilhelm, H. A. and M . L. Andrews, "Liquid-Liquid,Extractor: Appl ica t ion t o Sepa ra t i on o f S t ron t ium and Barium. " .1nd. & ' ~ n g . Chem. p rocess . Design, 1 : 305-309, October 1962. -

Wilhelm, H . A . An Apparatus f o r Counter Curren t Liquid-Liquid So lven t Ex t r ac t i on . Ames Laboratory, Ames, IA, January 24, 1951.

Wilhelm, H . A. and R . A . FOOS, A Countercur ren t Liquid-Liquid Ex t r ac to r . Ames Laboratory, Ames, IA, September 3, 1954.

Wilhelm, H . A. and R . A . Foos, "Countercur ren t Liquid-Liquid E x t r a c t o r . " *

Ind. Eng. Chem., - 51 :633-636, 1959.

Williams, J . A. and D. J . L i t t l e , "Hydrodynamics of Pulsed Columns. I . Calcu- l a t i o n o f the Amplitude and Pressure Development i n a Simple System." U . K . A t . Energy Au tho r i t y , Ind. Group. 8078, 1958.

Woodfield, F . W . and G. Sege, "A Louver-Plate R e d i s t r i b u t o r f o r Large Diameter Pulse Columns." Chem. Eng. Proqr. Symp. S e r . , a ( 1 3 ) ; 1 4 , 1954.

Woodle, H. A. and F. C. v i l b r a n d t , "Mechanisms by Which Ul t r a son ic Energy Affects Trans fe r Rates i n Liquid-Liquid Ext rac t ion ." AIChEJ, 5:296-298, June 1960.

Yakovlev, G. N. , e t a1 . , "Small Cent r i fuga l Ex t r ac to r . " A t . Energ. , 28:244-245, March 1970. - Yeager, J . H . , e t a l . , So lvent Ext rac t ion Apparatus Using J e t Mixers, U.S. Pa t en t 2,759,801, U.S. Pa t en t Of f i ce , Washington, DC, August 21, 1956.

Zakanycz, S., Measurement of Dispersion and Coalescence (Disengaginq) Time. National Lead Company o f Ohio, J u l y 14, 1958.

Ze t i rov, A. P. and M. M. Senyavi n, E x t r a c t i on--Theory, Appl i c a t i o n s and Apparatus. Moscow, Gosatomizdat, 1962.

Ze i r o v , A . P. and M. M. Senyavin, Ext rac t ion : Theory, Appl ica t ions and Equipment. Number 2. , Moscow, Gesatomizdat, 1962.

Z i eh l , L . , Ex t r ac t i on Column. U.S. Pa t en t 3,318,668, U.S. Pa t en t Of f i ce , Washington, DC, May 9 , 1967.

APPENDIX A

PREVIOUSLY UNPUBLISHED DATA USED I N THE LIATERATURE REVIEW

APPENDIX A

PREVIOUSLY UNPUBLISHED DATA USED IN T H E LITERATURE REVIEW

The information contained in these citations is important enough to

be included in the literature review even though it had never been published.

Therefore, to make these citations available to the reader, they are pub-

lished in this appendix.

1 . A . B. Greninger 2. J . S. McMahon 3 . J . S. Parker 4. W.J.Dowis 5. C. A. Rohrmann 6. R . H . Beaton 7. W . K. Woods 8. W. K. MacCready 9. W. I . Petnode

10. F . W . Woodfield 11. F. A . Hollenbach 12. W. B. Webster 13. R. E . Tomlinson 14. H . D. Middel 15. J . M . Frame 16. J . B . Fecht 17. V . D . Nixon 18. J . 0. Ludlow 20. D & C F i l e s

February 2, 1952

TO: Fi 1 e

FROM: W . B . Webster

MINUTES OF MEETING-RDA N O . DC-4 WORKING COMMITTEE FEBRUARY 1 , 1952

PRESENT: F . A. Hollenbach R . E. Tomlinson C. A . Rohrmann J . 0. Ludlow F. W . Woodfield J . B. Fecht W . B. Webster

The meeting was called for the purpose of discussing the advantages and disadvantages of pulse column and mixer-settler type contactors. I t was pointed out tha t the selection of the type of contactor t o be used in any new separations f a c i l i t y should be made a t the e a r l i e s t possible date in order fo r RDA DC-4 to proceed in the most e f f i c i en t manner. The selection of the type of contactor would n o t only a f fec t the building arrangement, b u t also a large part of other development work now being done on such items as pulse mechanisms, hot feed pumps, flow control devices, instrumentation, methods of remote maintenance, e tc . I t was also pointed out tha t although additional t e s t work would be required a f t e r the selection of a contactor, the basic character is t ics of the two types under consideration, upon which a decision would probably be based, a re now known.

The members of the committee who recently vis i ted the Savannah River mixer-settler p i lo t plant described the methods being used t o operate a mixer-sett ler in tha t plant, par t icular ly the method of hot flow con- t r o l . A two hour discussion followed concerning the merits of the two types of contactors. Points l i s t ed below were brought out during the discussion.

OPERATION AND ENGINEERING

1 . A separations f a c i l i t y using a mixer-settler type contactor with a j e t type hot feed control system as now being operated a t Savannah

File - 2 - February 2 , 1952

River could be operated and maintained easier , cheaper and w i t h more assurance of continuity of production than a pulse column type plant.

2. A large amount of the advantage of the mixer-settler as stated i n (1) above i s inherent i n the hot flow control system which uses no hot pumps, valves, or rotameters. I t i s recognized tha t i t may pos- s ib l e to adapt such a flow control system t o a pulse column although i t i s believed i t would be somewhat more d i f f i cu l t .

3 . If a j e t type flow control system was used on a pulse column the operating advantage of a m i xer-sett l e r would be reduced to:

a . A decrease i n the distance from which remote maintenance i s carried on.

b. The el imi nation of the mechanical ly and el ectr ical ly complex pulse mechanism by the use of small, simple and cheap agi ta tors .

4. Although studies under way to determine the e f fec t of the use of mixer-settlers or pulse mechanisms on building s ize and cost have not progressed suff ic ient ly t o show conclusive resu l t s , i t i s i n d i - cated that the e f fec t on building costs would be small.

5. Although the estimated cost of a mixer s e t t l e r u n i t i s less than the cost of a pulse u n i t , the e f fec t on the over a l l plant cost would probably be small. A larger savings would be made from the use of the j e t feed control system rather than a hot pump valve and rotameter system, b u t again, probably would not a f fec t the overall plant cost appreciably.

TECHNICAL

1. A mixer s e t t l e r type contactor i s slower to recover from an operating upset therefore processing larger quantit ies of off-specification material for a given upset.

2. There a re certain conditions under which a mixer s e t t l e r could be operated from which c r i t i c a l i t y problems would ar i se .

3 . Although suf f ic ien t information i s available to specify the cell space required for a mixer-settler type contactor, additional t e s t work would be required t o furnish fu l l process information on a u n i t sized for o u r proposed plant.

4. Yore "on s i t e " process data and experience are available a t Hanford Works on pul se col umns than m i xer-sett l ers .

WBW: emb

File - 3 - February 2, 1952

5. The j e t flow control system would have a smaller range of through- p u t than a pump-valve-rotameter system.

6. J e t s a re l ike ly t o plug and have a low head capacity fo r breaking such plugs.

Additional discussion on the selection of the type of contactor was post- poned pending discussions t o be held with the Design Committee, Thursday, February 7 , 1952.

WBW: ernb

OFFICIAL USE ONLY

1 . R . H . Beaton 2. R . B. Richards 3. A. R . Maguire 4. J . M. Frame 5. C. E. Kent 6. R. E . Smith 7 . F. W. Woodfield 8. F. W. Albaugh

9. C . M . Slansky 10. V . R. Cooper 1 1 . J . G . Bradley 12. E . Doud 13. C. Groot 14. J . T . Stringer 15-98. Extra

March 9 , 1950

TO: R . B. Richards

FROM: V . R . Cooper C . Groot

DESIGN CONSIDERATIONS FOR A PULSE COLUMN SYSTEM

I. Introduction

The pulse column, a countercurrent flow vertical type extractor originally described by W. J . D . Van ~ i j c k , ( f ) has been investigated by the Chemical Research Section and the Chemical Development Section with respect to i t s adaptabili ty to solvent extraction systems represented by the Redox and TBP processes. The resul ts have been very favorable. The H.T.U. values have been lower than obtainable with packed columns and the capacities and flooding rates are almost as high as these obtainable with large packing. In the development of complete engineering specifications relating the performance of the solvent extraction unit to spacing of the perforated plates, s i ze of the perforations, percentage "open" area, pulse frequency, pulse amplitude, i t appears that only experimental studies will reveal the desired information. However, the design information concerned with the quantitative force or pressure effects of pulsation on the pulse transmitting system and the pulse column proper are subject t o mathematical analysis as i l lustrated in the following development:

11. Objectives

The objectives of t h i s investigation were to evaluate the hydraulic forces in the pulse column, and determine the i r effects on pulse column design.

111. Summary and Conclusions

The important pressures in the system are the hydrostatic heads and

(1) U.S. Patent 2,011,186, August 13, 1935

OFFICIAL USE ONLY

OFFICIAL USE ONLY

the acceleration pressure in the pipe l ine connecting the pulse generator t o the column. This pressure may be computed for any point of the cycle; i t reaches a high negative value a t the pulse generator when the pulse flow changes from positive to negative. The minimum value of the accelera- t ion pressure i s given by

where k = half cycle pulse volume 1 = length of pipe p = density of solution i n pipe w = cycles per unit time D = diameter of pipe g = acceleration of gravity

Since k , 1 , p , W , and D are commonly presented in the inconsistent units of cubic inches, f e e t , specif ic gravity, cycles per minute, and inches, and since g i s constant, i t i s desirable to revise the constant term, thus

2 klpwL 'mi n = -7.83 x 1bs f t - ' in-3 min -

D

where the dimensions a re now cubic inches, f e e t , specif ic gravity, cycles per minute, and inches respectively, and Pmin. i s i n pounds per square inch.

If the algebraic sum of the absolute pressures (atmospheric, hydro- s t a t i c , and acceleration) i s less than the vapor pressure of the pulse f lu id , cavitation will occur and the system will be inoperable.

From t h i s equation i t may be shown tha t a pulse d is t r ibutes i t s e l f between two connecting vessels such as a column and a jackleg, so tha t the volume entering each vessel i s proportional t o the cross-sectional area and inversely proportional to the 1 engths. - IV. Discussion

b

The pulse column system components are:

1. Pulse generator. A single or multiple piston-cylinder system with adjustable length stroke driven by a constant speed dr iver .

2. A transmitting system. This consists of a constant diameter pipe l ine joining the pulse generator to the base of the col umn.

OFFICIAL USE ONLY

OFFICIAL USE ONLY

3. A pulse column. This consists of a vertical cylinder containing fixed horizontal close f i t t ing perforated plates. The diameter i s constant within the portion of the column containing the perforated plates. A larger diameter settling chamber surmounts the mixing or extraction section.

The forces and resistances in the pulse column system have been arbi- t rar i ly divided as indicated below. They will be examined in the order l is ted.

1 . Accel eration 2. Hydrostatic 3. Fluid friction

1 . Accel erati on

The method for determining the forces resulting from the acceleration of a fluid in a conduit of constant cross sectional area apply to a l l parts of the pulse system, i .e . , column section, transmission l ine and f i t t ings . I n the following development only the force due t o acceleration of the fluid in the transmission l ine will be examined inasmuch as that i s the major one. The case for the forces in the column due t o acceleration i s identical in development.

The force required t o accelerate an object i s equal t o i t s mass times i t s acceleration ( F = ma), or i t s weight times i t s acceleration divided by the acceleration of gravity ( F = w&). The weight of the fluid in the pipe i s

where 1 = length p = density A = cross-sectional area

The acceleration i s the f i r s t derivative of the linear velocity, which we wi 11 compute by way of volume velocity from the total material that has passed a given point.

Let V = ;s in 2nwt + L t

where v = total material past a given point a t time t k = half cycle pulse vol ume w = cycles per unit time t = total elapsed time L = l ight phase flow rate. A t time t = 0 the position of the pulse generator midstroke.

piston i s

OFFICIAL USE O N L Y

OFFICIAL USE ONLY

- 4 -

The term "Lt" represents the amount of l ight phase that has passed a given point from the steady s ta te flow. The term " k sin 2rwt" represents the pulse. When w t = n , where "n" i s an integer, txe pulse term i s zero. As w t increase t o n + 114, corresponding t o & quarter turn of the pulse pump, the term 4 sin 2nwt a1 so increases to 7, the maximum value of the pulse amplitude. A t n + 112 we are back t o zero, and n + 314 we get the minimum value. A t n + 1 a new cycle s ta r t s .

i s the rate of change of volume with time, or the flow rate. If we divide th is by the cross-sectional area "A" we have the linear velocity.

dV - knw cos 2nwt + L - - Ad t A

The rate of change of the linear velocity with time i s the acceleration, or

a = -2 kn2w2 sin 2nwt A

The force necessary for such accelerations i s thus:

F = w & = (lpA) (-2kn2w2 sin Lnwt) g A g

B u t pressure is ' force per unit area so:

P = (lpA) (-2~n'w' sin 2nwt) - - -2 lpkn2w2 sin Znwt A A g A g

n ~ 2 or , since A = Twhere D i s the diameter

P = -8nlpk w2 sin 2nwt

~~g

This question i s valid in any system of units. Since i t i s accepted practice t o express pressure in terms of pounds per square inch the constant i s revised. Consolidation of the conversion f,actors necessitated by the use of the units shown below for the other terms in the equation results

-6 1 bs mi n in a constant w i t h the value of 7.83 x 10 f t i n - $ .

2 P = -(8)(3.1416)(62.4 1bs f t -3 ) l k p w sin 2nwt

-1 2 -3 2 (32.2 f t ~ e c - ~ ) ( 6 0 sec min ) (1728 in3ft ) D

OFFICIAL USE ONLY

OFFICIAL USE ONLY

P = 7.83 x 1 o - ~ 1 bs min2 klpw2 sin 2nwt f t in3

The equation above i s valid in any units, b u t more particularly, gives P in pounds per square in. when

k = half cycle pulse volume - cubic inches 1 = length of l ine - feet p = specific gravity - dimensionless w = cycle per minute D = diameter of pipe - inches

For design consideration, the only cases we are interested in are the cases where P reaches i t s minimum (most negative) pressure. A t th is point sin 2 w t = 1 , hence

- -7.83 x 1 0 ' ~ 1 bs min2 klpw 2 - 'mi n f t in3 D2

Connection in series

For units in series with different cross-sectional areas, such as a transmission l ine with different diameters and a column, the individual pressures due t o acceleration are additive.

Connection in paral 1 el

For units in paral lel , such as the pulse column and i t s jackleg, the distribution of forces may be found as follows:

The pressure in the column a t the point of attachment of the jackleg will be the same as in the bottom of the jackleg and may be determined as indicated.

P = -8nklpwL sin 2nwt - - -8nk'l 'pwL sin 2nwt ~2 D12

kl - k ' l ' or - - ~2 7

Hence, the pulse distributes i t se l f among two communicating vessels directly proportional t o the squares of the diameters and inversely as the lengths.

2. Hydrostatic head

By selecting the point of entrance of the pulse transmission line into

OFFICIAL USE ONLY

OFFICIAL USE ONLY

the column as the datum plane and calculating the individual static pressures in the transmission line and column the hydrostatic head becomes the sum of the two pressures if the generator is below the datum plane or the difference of the column pressure minus the transmission line pressure if the generator is above the datum plane.

3. Frictional forces.

The frictional forces in a pulse column system are low, and generally may be neglected in designing a pulse column system. They are included for purposes of illustration in the detailed example in the appendix.

Illustrative examples

For purposes of illustration a case approaching the conditions expected in the TBP process will be considered.

Given: Col umn diameter 20 in. Pulse amp1 itude in column 112 in. Line length (existing 1 ine through concrete) 15 ft. Line diameter ( " I I I 1

I' > 2 in. Specific gravity of fluid in line

I I I t 0.803

Vapor pressure " " 0.3 p.s.i. Pressure in vapor space above column 14.7 p.s.i. Hydrostatic head between top of column and pulse pump 0.0

To find: What is the maximum frequency at which this system can be operated?

A1 lowable acceleration pressure at pulse pump -14.7 + 0.3 = -14.4 p.s.i.

Pulse volume

OFFICIAL USE ONLY

OFFICIAL USE ONLY

Example I1

Given Col umn

Height Diameter Pul se amp1 i tude i n column Specific Gravity (average) Pul se frequency cycl es/min.

Pipe 1 ines (Section A and B ) Section A

Length Diameter Specific Gravity

Section B Two existing l ines through concrete in para1 1 e l , each Length Di ameter Specific Gravity

Hydrostatic head a t pulse pump Vapor pressure a t pulse pump Pressure a t top of column

12 f t . 20 l 'n. 0.5 in. 1.26

50.

16 f t . 4 inches 0.803

15 f t 2 inches 0.803

To find - Will i t operate?

A. Find k n

B. Find acceleration pressure in each section.

1. Column

2. Section A of pipe

3 . Section B of pipe

C. Find minimum pressure a t pulse pump

P = 14.7 - 0.11 - 2.5 - 4.6 + 0 - 7.5

P i s greater than 0.3, the vapor pressure of the pulsed f lu id , and the system wi 11 operate.

OFFICIAL USE ONLY

OFFICIAL USE ONLY

- 8 -

Appendix

A Redox system as defined below was comprehensively examined under two conditions. The results illustrate the negligible effect of factors other than hydrostatic head and pressure due to acceleration.

System Dimension and Operating Conditions

Case I Case I1

Column Diameter, Inches 8.0 8.0

Column Height, Feed 15.0 15.0

Number of Plates 60 6 0

Free Area of Plates, percentage 23 23

Length of Transmission Line, Feet 2 5 100

Diameter of Transmission Line, Inches 1.5 1.5

Pulse Frequency, CyclesIMin.

Pulse Amplitude, Cu.In./Stroke

Pulse Amplitude, In./Stroke 0.50 0.90

Elevation of Generator above Base of Column, Feet 0 2 5

Specific Gravity, In Column 1.3 1.3

Specific Gravity, Light Phase In

Light Phase Flow rate, Gals./Hr./Sq.Ft.

Heavy Phase Flow rate, Gals./Hr./Sq.Ft. 660 660

Pressure and Resistance Values of wt

Case I

Hydrostatic

Fluid Flow Friction

Accel eration +6.29 0 -6.29 0

Atmospheric 14.7 14.7 14.7 14.7

Absolute pressure at pulse 29.56 24.26 16.98 22.72 generator

OFFICIAL USE ONLY

OFFICIAL USE ONLY

- 9 -

Case I 1 Values of w t

Hydrostatic

Fluid Flow Fr ic t ion 00.42 5.68 0.42 -4.11

Acceleration " 45.36 0 -45.36 0

Atmospheric 14.7 14.7 14.7 14.7

Absolute Pressure a t Pulse 60.26 20.16 -30.46 10.37 Generator

Case I 1 i s notoperable, a s the pressure a t the pulse generator drops below the vapor pressure of t he pulsed f l u i d , and cavi ta t ion wil l occur.

OFFICIAL USE ONLY

cc: WB Webster CA Rohrmann FW Woodfield RE Tomlinson FA Hol lenbach OC Schroeder

Richland, Washington February 26, 1952

TO : F i l e

FROM: F. A. Hol lenbach

RDA-DC-4 - EQUIPMENT STUDY - ROUGH DRAFT

I. Comparison o f Pulse Columns and Mixer S e t t l e r s (D is regard ing Flow System)

D . The E f f e c t on O p e r a b i l i t y and Maintenance

ITEM

1. R e l i a b i l i t y o f equipment

MIXER-SETTLER

l a . Pulse Mechanism vs As many as 15-20 f r a c t i o n a l H.P. a g i t a t o r s a g i t a t o r s (mechani- per contactor . These a r e d i r e c t d r i v e and c a l ) overpowered several t imes. Spare stages

prov ided so t h a t l oss o f several a g i t a t o r s would no t cause process d i f f i c u l t y and would a l l ow f o r a planned shutdown f o r r e - p a i r o r replacement. A l l a g i t a t o r s w i l l be i n "hot" Zone.

A g i t a t o r s a re simp1 e mechanical l y w i t h bearings and r o t a t i n g s h a f t being the o n l y wearing pa r t s .

PULSE COLUMN

Only one mechanical u n i t per contac tor , however, u n i t conta ins wearing p a r t s such as reduc t i on gear box, gear and rack, and r e c i p r o c a t i n g p i s t o n w i t h r i n g s . Unless pu lse generator i s spared i n p lace, which i nvo l ves remote v a l v i n g problems, f a i l u r e o f u n i t causes immediate shutdown f o r replacement. Al though i t may be poss ib le and p r a c t i c a l (because o f p u l s i n g o f c o l d streams) t o l o c a t e pu lse gener- a t o r i n a "co ld" zone, f a i l u r e o f the u n i t , un less spared i n p lace, would s t i l l cause immediate shutdown. Loca- t i o n i n a c o l d zone wouTd a l l o w f o r a

preven ta t i ve maintenance program, however on a planned shutdown basis which would minimize f a i l u r e s dur ing opera t i ng per iods .

Comment: There has as y e t been no opera t ing experience a t Hanford t o determine the l i f e and r e l i a b i l i t y o f pu lse generators, al though several thousand t r o u b l e f r e e hours have been accumulated on an experimental u n i t . S i m i l a r l y t he re i s l i t t l e l i f e experience on pump mix a g i t a t o r u n i t s . How- ever, they are made from standard designs which have been proven t o be r e l i a b l e i n i n d u s t r y f o r many years.

Mixer S e t t l e r s a re more simple and rugged mechanical ly and should prove more r e l i a b l e based on the above po in ts .

l b . Pulse Mechanism vs A g i t a t o r motor speed c o n t r o l i s achieved by Pulse generator frequency i s con- a g i t a t o r s ( e l e c t r i c a l ) use o f v a r i a b l e frequency AC cu r ren t . The t r o l l e d by a v a r i a b l e frequency

speed o f a l l a g i t a t o r s o f any one contac tor AC c u r r e n t supp l ied by a s u i t a b l e can be var ied. generator.

Comment: No appreciable d i f f e r e n c e i s apparent.

l c . Columns vs mixer s e t t l e r boxes (mechanical )

Mixer S e t t l e r i s a b a f f l e d box about 20' Pulse column i s a maximum o f 20" i n long X 6 ' wide x 1 ' deep. No d i f f i c u l t i e s diameter X 40' h igh w i t h per fo ra ted are an t i c i pa ted . p la tes . Mechanical ly no d i f f i c u l t i e s

a r e an t i c i pa ted .

Comment: No d i f f e r e n c e i s apparent here.

I d . Rangeabi 1 i ty o f throughput o f the contac tor .

Manufactur ing Department has no data regarding the ranges over which t h i s equipment may be operated; however, o ther f a c t o r s being equal, reasonably wide ( 2 o r 3 t o 1 ) operat ing ranges a re requi red. No appreciable d i f f e rences a re a n t i c i p a t e d between the mixer s e t t l e r and pu lse column contactors.

l e . Ease o f s t a r t - u p and shut-down

Mixer S e t t l e r has about 1/3 g rea te r Pulse columns have l e s s ho ld up. volume; thus longer s t a r t - u p and shutdown per iods a re an t i c i pa ted .

Comment: Smal ler ho ld up i s o f advantage on extended shut-downs and a l s o f o r changes i n process cond i t ions . Pulse columns a re s l i g h t l y favored here.

If. Columns vs Mixer S e t t l e r Each mixer s e t t l e r contac tor i s an i n t e g r a l 1B pu lse column i s s p l i t i n t o two (quan t i ty o f equ i pmen t ) u n i t . sect ions, because o f he igh t consid-

e ra t i ons , w i t h a d d i t i o n a l pump tank requi red.

Comment: Mixer s e t t l e r favored by t h i s cons idera t ion .

2. Maintenance

2a. E f f e c t o f canyon he igh t Mixer s e t t l e r s a re low u n i t s and w i l l have Pulse columns a re long u n i t s r e q u i r i n g no e f fec t as such on canyon h e i g h t and c e l l depth t o accommodate them and may r e s u l t i n canyon h e i g h t reduct ions. a h igh crane f o r placement and removal.

C e l l bottom t o crane r a i l d is tances i n excess o f 60 f e e t a re regarded unfavorably. Viewing w i t h o p t i c s becomes i n c r e a s i n g l y d i f f i c u l t . Swinging o f t he crane hooks and wrench and t w i s t i n g o f cables would slow down remote maintenance immeasurably.

Comment: Unfavorable canyon heights i n case o f pu lse columns i s a b i g p o i n t f a v o r i n g mixer s e t t l e r s . Excessive c e l l f l o o r t o crane r a i l d is tances cannot be accepted.

I-C, L c a . 7 5 In C, C, V)u L U c a Q 0 aJ U P

S P I n 0 3 -r 3 U 7 7 0

OaJ3 u C, 3 L a m 3 'r E O O L Q I n 5 E

r a J c n ~ ~ + ' InaJ5mu .r- L Q) a 7

5

u 4

K a J n > n o

> a s L 0 % PI- 0

Comment: Unless a l l pulsed streams were "co ld" streams, t h e removal o f t h e pu l se rs f rom t h e canyon t o a " c o l d SWP" g a l l e r y loses some o f i t s a t t rac t i veness . Even w i t h p u l s i n g o f c o l d streams, con- t am ina t i on o f "co ld" zone cou ld r e s u l t from back up o f "ho t " s o l u t i o n s i n t o pu l se r .

2d. B u i l t up o f As c u r r e n t l y conceived mixer s e t t l e r These u n i t s a re f l u s h a b l e and s o l i d s i n con tac to r u n i t s a re no t f l u s h a b l e o r d ra inab le . Whi le d ra inab le . Plugging o f t he s ieve u n i t t he presence o f apprec iab le q u a n t i t i e s o f p l a t e holes i s n o t a n t i c i p a t e d i n

s o l i d s i n the system i s ques t ionab le a t l i g h t o f experimental operat ions. present, f l u s h i n g and c lean-out p e r i o d i c a l l y w i 11 be requ i red f o r accountabi li t y reasons.

Comment: Pulse columns are favored by t h i s p o i n t .

2e. F lush ing and decontaminat ion Not f l ushab le and dra inab le , thus n o t r e a d i l y F lushable and d ra inab le b u t quest ionable sub jec t t o decontaminat ion e s p e c i a l l y w i t h how successfu l decontaminat ion would many corners, pockets, e t c . be beyond t h i s . Corners o f p l a t e s

and s e t t l i n g chambers would be impossib le t o c lean.

Comment: S l i g h t advantage t o pulse columns; however, i n general, decontaminat ion and con tac t maintenance f o r r e p a i r s i s n o t contemplated f o r any t ype o f contac tor . Vessel f a i l u r e s n i l t o date. Replacement c o s t would be on l y comparison bas is .

11. Comparison o f Pump-Valve-Rotometer Flow System w i t h the J e t - O r i f i c e Flow Systems

J e t - O r i f i c e Pump-Valve Rotometer

1. R e l i a b i l i t y

l a . Pumps vs j e t J e t i t s e l f very r e l i a b l e . Past f a i l u r e s Pump experience i s l i m i t e d t o date due t o gasket f a i l u r e s and p lugging. b u t many wearing p a r t s a re invo lved. Welding f i t t i n g s o r use o f f l e x a t a l l i c gaskets should so lve gasket f a i l u r e s ; p lugg ing due t o broken gasket p ieces o r p r e c i p i t a t e handled. No problem here.

Comment: J e t i s i n h e r e n t l y s impler and super io r mechanical ly .

C, L .r ? .r aJ luC, 5 3 E n u >n 0 aJ C, m s u V) 0 s s s u L .r 0 5 l > U 7

a J O L O > E a J a J V ) ? sC, 5rc.r aJ 0 > O ? E t '

s 0 I .- P aJ V) .r -0 0 PC, 5

O L S E G a J L a J I

a J E L Q a J 3 3 0 U E aJ L ? aJ O L L G - r

- U a J '4- 3 m a 3 l a s s

bl .r c

A= m E: 3 0 0 -7 LC, A= a C, U .-

.r 't 7

0 'E 't Z O O

C, '4- . C, C,

C , . C, rc 't. 't 3 't

t' 't . C, C,

C , . C, 't 't 't 3 '4-

I P a J -I- s s 5 u L W 0

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