dta + ir + bet characterisation of the album samples · dta + ir + bet characterisation of the...

DTA + IR + BET Characterisation of theALBUM samples

Stephan Kaufhold & Reiner Dohrmann

Analyses performed

Kaufhold & Dohrmann: DTA and IR of ALBUM samples

XRF, XRD (powder), CEC (Cu-Triene), DTA, IR, BET, LECO Missing:

XRD coarse fractionsXRD clay fraction (texture slides)XRD Rietveld calculation (AQ®)CEC (AgTu, BaCl2)LCD (alkylammonium)

XRD powder


Some minerals questionable…What might help ?

JNB Album CAN Album ROK Album CAL Album COB Album IBE Album LOT Album ASH Album FRI Album FEB Album IKO Album´Kunigel V1´ ´Deponit Ca N´ ´Rokle´ Ćalcigel´ Ćallovo Oxf.´ ÍBECO Seal´ ´MX 80´ Ásha 505´ ´Friedland´ ´Febex´ Íkosorb´

Bentonite Bentonite Bentonite Bentonite Clay Bentonite Bentonite Bentonite Clay Bentonite BentoniteJapan Milos? CzechRepl. Bavaria? Bure, F ?? Wyoming, US India Germany Almeria, Sp. Milos, Gr

XRDMontmorillonite + + + + ? + + + + +Mixed layers ? +-Musc/Illite - +- +- - - +-Quartz +- - +- + - +- + -Feldspar - - -Clinoptilolite -Calcite - - - + - - -Dolomite - - -Aragonite -Kaolinite -- - +- +-Chlorite - -Cristobalite - -Gypsum -- -Goethite -Siderite -Rutile/Anatase - --Apatite --Pyrite - - - -- --

Of course: LECO, IR, DTA

Infrared-spectroscopy


Weigh 1 mg sample and 200 mg KBr: Mixing by mortar

Press a pellet out of the mixture

Measure background(200 mg KBr only)

Measure sample

VakuumIR

-sou

rce

dete

ctor



Advantage 1low detection limitkaolinite, organic matter, carbonates, quartz, (sulphates)

7007508008509009501000

rela

tive

abso

rban

ce

wavenumber [cm-1]

AlA

lOH

(!k

aolin

ite!)

JNB

ROK AlF

eOH

(c

arbo

nate

)

AlM

gOH

Qua

rtz

Advantage 2octahedral layer compositionof smectites can be estimated(e.g. Fe-rich or not)



Disadvantage 1a lot of minerals cannot bedetected being present as minor component

Disadvantage 2quantitative information canbe obscured by microstructure

IR

no quartz

Differential thermal analysis


Weigh appr. 200 mg in Pt-cruciple

sample is heated and investigated with respect to

weight loss

energy (exo-, endo-thermal reaction)

CO2, H2O, SO2by massspectrometry

ovenoven++balancebalance

MSMS

0.00

0.00

0.00

0.00

0.00

0.00

50 150 250 350 450 550 650 750 850 950 1050

T [K]

H2OH2O

dehydroxylationcis vacant mont

/ low Fe

dehydroxylationtrans vacant mont

/ high Fe

JNB

ROK

Differential thermal analysis


Advantage 1low detection limitsulphides, sulphates, organicmatter, carbonates

Advantage 2information about octahedrallayer vacancy and/or Fe content can be gained

Some scientists claimthat peak positiondepends on vacancy. However, a strongcorrelation of FeVI-content withdehydroxylation at 500°C is known !!

JNB


XRD: montm., quartz, clinopt., calcite

Where is S ?

LECOCtotal [wt.%] 0.43Corg [wt.%] 0.07Cinorg [wt.%] 0.36

Stotal [wt.%] 0.34

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

50 150 250 350 450 550 650 750 850 950 1050

T [K]

H2OCO2SO2DSC

MS small SO2 peakDSC: exothermal=> some sulphide

dehydroxylation

CO3 decomposition

0.00

0.00

0.00

0.00

0.00

0.00

0.00

50 150 250 350 450 550 650 750 850 950 1050

T [K]

CO2SO2

MS small SO2 peakDSC: exothermal=> some sulphide

CO3 decomposition

Decomposition of organic matter

pyrite0.5-1 wt.%(difficult tosee with XRD)

ROK


XRD: montm., muscov., quartz, rutile/anatase?, apatite?


Stotal [wt.%] 0.02

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

50 150 250 350 450 550 650 750 850 950 1050

T [K]

H2OCO2SO2DSC

recrystallization

water (oxidation of OM) dehydroxylation

Cis + trans vacant mont

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

50 150 250 350 450 550 650 750 850 950 1050

T [K]

CO2SO2

organic matter

carbonates

A closer look to IR

ROK


XRD: montm., muscov., quartz, rutile/anatase?, apatite?


Stotal [wt.%] 0.02IR: tracekaolinite

carbonate at detection limit

F-rich mont. (0.7 FeVI/EC)

muscovitequestionable

400900140019002400290034003900

wavenumber [cm-1]

rela

tive

abso

rban

ce

ROKROK 150°C

SiO

Qua

rtz/C

TO

Kaol

inie

t/Hal

loys

ite

dioc

tahe

dral

sm

ectit

e

wat

er

wat

er

carb

onat

e

Apat

ite?

Mus

covi

te?

20002200240026002800300032003400360038004000

rela

tive

abso

rban

ce

wavenumber [cm-1]

Kao

linie

t/Hal

loys

ite

dioc

tahe

dral

sm

ectit

e wat

er

C-C

org

anic

mat

ter

400600800100012001400160018002000

rela

tive

abso

rban

ce

wavenumber [cm-1]

Qua

rtz/

CTO

wat

er

carb

onat

e

Apa

tite?

Mus

covi

te?

Fe-r

ich

mon

tmor

illon

ite

750770790810830850870890910930950970

Wellenzahl [cm-1]

rela

tive

Abs

orpt

ion

AlA

lOH

- FeA

lOH

+ Fe

AlO

H

AlM

gOH

Bei

delli

t

SiO

(Qz)

/FeF

eOH

Bei

delli

t

MgVI

0,30

0,66

0,60

0,75

FeVI

0,81

0,82

0,61

0,45

887

882

877

879

K-F

sp

M

RB

UA

FE

y = -24,05x + 897,42R2 = 0,9588

876

878

880

882

884

886

888

0,4 0,5 0,6 0,7 0,8 0,9

Fe-Atome/EZ

Pos

ition

der

FeA

lOH

-Ban

de [c

m-1

]

FE

ROK

Conculsions


DTA and IR complement XRD results

DTA and IR are consistent with LECO analysis(no discrepancies between IR, DTA, LECO detected)

LECO provides accurate figures related to the abundance of important minerals as sulphides & sulphates, carbonates –even small changes (before and after) can be detected !

Detection limits (ca.)Cinorg Sulphides Sulphates Kaolinite

Infrared 0.2 wt.% / > 1 wt.% 0.1 wt.%DTA-MS 0.1 wt.% 0.1 wt.% 0.2 wt.% > 1 wt.%

What do we learn from BET ?


N2 adsorption ⇒ microporosity rather than real surface areaLeaching creates micropores ⇒ changes can be observedBET SSA depends on Ca / Na occupation… why ?

y = 1,0x + 7,2R2 = 0,3

0

20

40

60

80

100

120

140

0 10 20 30 40 50 60 70 80

Ca2+ [meq/100g]

BE

T S

SA

[m2 /g

]

PhD Ms. Klinkenberg (microstructure and physical propertiesof clays) provides some insight !



Bentonite moroccoCa and Na saturateddispersed & dried

CaCa NaNa

BET SSA depends on micro- and mesoporosity and henceon microstructure (arrangement of minerals to each other)

dense & lamellarmicrostructure

loose & ´card-house´ relatedmicrostructure

96 m96 m22/g/g 51 m51 m22/g/g



In case of LOT A2 experiment BET reflects gypsumprecipitation (in pores)

0

2

4

6

8

10

12

14

16

18

0 10 20 30 40 50 60 70 80 90 100

distance from Cu tube [mm]

spec

ific

surfa

ce a

rea

[m2 /g

]

BET SSA is suitable to detect ´changes´ of the clay, however, the physical meaning might be different

DTA + IR + BET Characterisation of theALBUM samples

Stephan Kaufhold & Reiner Dohrmann

…

LECOCtotal [wt.%] 3.94Corg [wt.%] 0.65Cinorg [wt.%] 3.29Stotal [wt.%] 0.68

COB


XRD: montm/ML, muscov., quartz, fsp., calcite/dolomite, kaolinite, chlorite, pyrite?

400600800100012001400160018002000

rela

tive

wavenumber [cm-1]

Car

bona

te

dta + ir + bet characterisation of the album samples · dta + ir + bet characterisation of the...

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