short note of cement chemistry

1

Short Note of Cement Chemistry Indian Standard Code use in cement Chemistry

Cement IS 269:1989 – Specification for ordinary Portland cement, 33 grade

IS 455:1989- Specification for Portland slag cement

IS 1489(Part 1):1991 Specification for Portland pozzolana cement Part 1 Flyash based

IS 1489(Part 2):1991 Specification for Portland-pozzolana cement: Part 2 Calcined clay based

IS 3466:1988 Specification for masonry cement

IS 6452:1989- Specification for high alumina cement for structural use.

IS 6909:1990 Specification for super sulphated cement

IS 8041:1990 Specification for rapid hardening Portland cement

IS 8042:1989 Specification for white Portland cement

IS 8043:1991 Specification for hydrophobic Portland cement

IS 8112:1989 Specification for 43 grade ordinary Portland

IS 8229:1986 Specification for oil-well cement.

IS 12269:1987 Specification for 53 grade ordinary Portland

IS 12269:535 Specification for TRS-T40 grade ordinary Portland

IS 12330:1988 Specification for sulphate resisting Portland

IS 12600:1989 Specification for low heat Portland cement Instrument use in cement analysis IS 12803:1989 Methods of analysis of hydraulic cement by X-ray fluorescence spectrometer

IS 12813:1989 Method of analysis of hydraulic cement by atomic absorption spectrophotometer Apparatus use in cement analysis IS 5512:1983 Specification for flow table for use in tests of hydraulic cements and pozzolanic

materials

IS 5513:1996 Specification for vicat apparatus.

IS 5514:1996 Specification for apparatus used in Le-Chatelier test

IS 5515:1983 Specification for compaction factor apparatus

IS 5516:1996 Specification for variable flow type air-permeability apparatus (Blaine type)

IS 14345:1996 Specification for autoclave apparatus

Physical & Chemical Analysis of Cement IS 4031(Part 1):1996 Methods of physical tests for hydraulic cement: Part 1 Determination of

fineness by dry sieving

IS 4031(Part 2):1999 Methods of physical tests for hydraulic cement: Part 2 Determination of

fineness by specific surface by Blaine air permeability method


soundness


consistency of standard cement paste

IS 4031(Part 5):1988 Methods of physical tests for hydraulic cement: Part 5 Determination of initial

and final setting times


compressive strength of hydraulic cement (other than masonry cement)


compressive strength of masonry cement


transverse and compressive strength of plastic mortar using prism

IS 4031(Part 9):1988 Methods of physical tests for hydraulic cement: Part 9 Determination of heat of

hydration


drying shrinkage

2


density

IS 4031(Part 12):1988 Methods of physical tests for hydraulic cement: Part 12 Determination of air

content of hydraulic cement mortar

IS 4031(Part 13):1988 Methods of physical tests for hydraulic cement: Part 13 Measurement of water

retentivity of masonry cement

IS 4031(Part 14):1989 Methods of physical tests for hydraulic cement: Part 14 Determination of false

set

IS 4031(Part 15):1991 Methods of physical test for hydraulic cement: Part 15 Determination of

fineness by wet sieving

IS 4032:1985 Method of chemical analysis of hydraulic cement

IS 3535:1986 Methods of sampling hydraulic cement

IS 12423:1988 Method for colorimetric analysis of hydraulic

IS 4845:1968 Definitions and terminology relating to hydraulic cement. Use sand in cement IS 650:1991 Specification for standard sand for testing of cement.

IS 456:2000 Code of practice plain and reinforced concrete

Pozzolana material IS 1727:1967 Methods of test for pozzolana materials.

IS 12870:1989 Methods of sampling calcined clay pozzolana.

IS 3812(Part 1):2003 Specification for pulverized fuel ash Part 1 For use as pozzolana in cement,

cement mortar and concrete

IS 3812(Part 2):2003 Specification for pulverized fuel ash Part 2 For use as admixture in cement

mortar and concrete

IS 6491:1972 Method of sampling fly ash

IS 12089:1987 Specification for granulated slag for manufacture of Portland slag cement.

Coal IS 1350:1984 (Part-I) Methods of test Proximate analysis

IS 1350:1970 (Part-II) Methods of test Calorific value.

IS 1350:1969 (Part-III) Methods of test Sulphur analysis

IS 1350:1974 (Part-IV) Methods of test Ultimate analysis.

IS 1350:1979 (Part-V) Methods of test Special Impurity. Lime stone IS 1760:1991 (Part- I to V) Methods of Chemical Analysis of Limestone.

IS 1760 (Part 3):1992 Methods of chemical analysis of limestone, dolomite and allied materials:

Part 3 Determination of iron oxide, alumina, calcium oxide and magnesia

Gypsum IS 1288:1982 Methods of test mineral gypsum.

IS 1289:1960 Methods of sampling mineral gypsum

IS 1290:1982 Mmineral gypsum.

Bag IS 12154:1987 Methods of Light weight jute bags for packing cement

IS 2580:1995 Methods of Jute sacking bags for packing cement

IS 11652:1986 High density polyethylene (HDPE) woven sacks for packing cement

IS 12174:1987 Jute synthetic union bags for packing cement

IS 11653:1986 Polypropylene (PP) woven sacks for packing cement

3

Formula use in cement analysis.

Hydraulic Modulus: HM = CaO

SiO2 + Al2O3 +Fe2O3 (Typical Range: 1.7 to 2.3)

Silica Ratio: SM = SiO2

Al2O3 +Fe2O3 (Typical Range: 1.8 to 2.7)

Alumina Ratio: AM = Al2O3

Or Iron Modulus Fe2O3 (Typical Range: 1.0 to 1.7)

Lime saturation Factor: (For OPC Cement)

LSF = CaO- 0.7 SO3

2.8 SiO2 + 1.2Al2O3 +0.65Fe2O3 (Typical Range: 0.66 to 1.02)

Lime saturation Factor:

LSF = CaO X 100

2.8 SiO2 + 1.2Al2O3 +0.65Fe2O3 (Typical Range: 95 to 110)

Lime saturation Factor: (if Alumina modulus >0.64) -

LSF = CaO


Lime saturation Factor: (if Alumina modulus <0.64)

LSF = CaO


Bogus’ formula for Clinker Constituent (if Alumina modulus >0.64)

C3S = 4.071 CaO – (7.602 SiO2 + 6.718 Al2O3 +1.43Fe2O3 ) Note: CaO = CaO - F/CaO

C2S = 2.867 SiO2 - 0.7544 C3S

C3A = 2.65 Al2O3 - 1.692 Fe2O3

C4AF = 3.043 Fe2O3

C3S = Tri Calcium Silicate. (Molecular weight = 228 g/g mol)

C2S = Di Calcium Silicate. (Molecular weight = 172 g/g mol)

C3A = Tri Calcium Aluminate. (Molecular weight =270 g/g mol)

C4AF = Tetra Calcium Aluminate Ferate. (Molecular weight = 486 g/g mol)

(if Alumina modulus <0.64)

C3S = 4.071 CaO – (7.602 SiO2 + 4.479 Al2O3 +2.86Fe2O3) Note: CaO = CaO - F/CaO

C2S = 2.867 SiO2 - 0.7544 C3S

C3A = 0

C4AF+ C2F =2.1 Al2O3 +1.702Fe2O3

Bogus’ formula for Cement Constituent (if Alumina modulus >0.64)

Note: CaO = CaO - F/CaO

C3S = 4.071 CaO – (7.602 SiO2 + 6.718 Al2O3 +1.43Fe2O3+2.85 SO3)

C2S = 2.867 SiO2 - 0.7544 C3S

C3A = 2.65 Al2O3 - 1.692 Fe2O3

C4AF = 3.043 Fe2O3

4

Liquid Value:

LV= 1.13 C3A +1.35 C4AF + MgO +Alkalies

Burnability Index:

BI = C3S

C4AF + C3A

Burnability Factor:

BF = LSF + 10 SM – 3(MgO + Alkalies)

Coal Analysis:

NCV = 8455 – 114 (M% + Ash %) Cal/gm

UHV = 8900 – 138 (M % + Ash %) Cal/gm

GCV = PC X 86.5 – (60*M %)

PC = 100- (1.1*Ash + M %)

CV = % C*8000 + % H*32000

100 100

Coal Consumption: = Coal feed X 100

Clinker Production

Ash absorption: = % of ash in fuel X coal consumption/ 100

Raw meal to clinker factor: = 100-ash absorption

100-LOI

Specific Heat: V = NCV X % of coal Consumption

100

Insoluble Residue:

IR (max %) = X+4 (100-X) (Note: X= % of Fly ash)

100

(Note: In PPC Cement Fly ash use not less than 15% and not more than 35%)

(Note: In PSC Cement Slag use not less than 25% and not more than 70%)

Blain :

Blain = √Time X Factor

Factor = √Time

STD Blain

CYCLONE LOSS: = 100 (KF loss – Cyclone loss ) (100 – Cyclone loss) X KF loss Clinker to cement factor: = Clink. + Fly ash/Slag + additives (kg) Clinker consumed (kg) X-ray: = nʎ= 2d sin θ

(n= number of wave, ʎ= wave length, d= distance two layer, sin θ= angle of wave)

When bombarding of cathode ray on high melting point metal than reflected ray is called X ray.

Bulk Density : Cilnker = 1360 Kg/M3, Gypsum = 1.38 Mt/M3, Iron = 2700 Kg/M3, Lime stone = 1400 Kg/M3 Fly ash = 550 Kg/M3, Coal = 850 Kg/M3, Sand = 1600 Kg/M3, Cock = 480-640 Kg/M3, Cement = 1500 Kg/M3, Raw meal = 1250 Kg/M3,

X 100

5

Coal Grading: Coal is the combination of Organic (Carbon) and Inorganic (Si02, R2O3 etc) material. It is use for

heating porpoise. Grade A+M % UHV cal/g A <19.5 >6200 B 19.5-24.0 6200-5600 C 24.0-28.7 5600-4940 D 28.7-34.1 4940-4200 E 34.1-40.2 4200-3360 F 40.2-47.1 3360-2400 G 47.1-55.1 2400-1300 Un-grade >55.1 <1300 Type of Coal: 1. Anthracite 2.Buteminus 3. Lignite 4. Pith

Physical Analysis of PPC: TEST- Residue (sieve), Blain, Normal consistence, Setting time, Compressive strength, Soundness-(AC&LC) Blain (IS -4031 part-2) = 300 M2/kg minimum

NC Setting time Strength Auto clave Le-chate

IS- 4031 Part-4 Part-5 Part-6 Part-3 Part-3

Lab Tempture 270C ± 20C 270C ± 20C 270C ± 20C 270C ± 20C 270C ± 20C

Lab/Chamber R-Humidity

65% ± 5, Not less than

90%


90%

65% ± 5, Not less than 90%


90%


90%

Sample weight

300/400 gm 300/400 gm 200gm-cm, 600gm-1s+2s+3s

300/400 gm 100 gm

Water Requirement

Req.waterX100 sample weight

NC*0.85*S.Wt 100

(NC+3) *800 4 100

=NC NC*0.78*S.wt 100

Apparatus Vicat apparatus

Vicat apparatus

Vibrating & CSTm AC machine 2150C,

21 kg/cm2

Water Bath 100oC

Expend Time As possible vicat Reading

5-7 cm

As possible vicat Reading

5-7 cm

72 ±1hour- 16mpa 168 ±2hour-22mpa

672 ±4hour- 33mpa

RH-C-24hour ACM-3 Hour

RH-C-24hour WB-3 Hour

Other

Use needle 5mm

Use needle 2mm

Gaugeing 1min dry, 4 min wet

Gaugeing 5 min

IS Requirement

Initial – 30 min minimum

Final-600 min maximum

3 day- 16mpa 7 day- 22mpa

28 day- 33mpa

0.8 % max 10 mm max

STI (Scheme of testing & inspection) Form-1: FORMAT FOR MAINTENANCE OF TEST RECORDS WEIGHMENT CONTROL AT PACKING STAGE (Clause 6.2)

Date Shift No. Of Bag Net mass of bags from nozzles No.1, No. 2, Remark

Form-2: RAW MATERIAL TESTING (CL.7 of STI)

Date of receipt of material

Date of testing Name of the

Material Source of supply and

consignment No. Details of analysis for Specified requirements

Form-3: PRODUCTION DATA (POST GRINDING DETAILS OF PRODUCTION ACCEPTED & REJECTED FOR ISI MARK)

Shift Quantity Passed for ISI Marking Rejected Remarks

6

Form-4-A: POZZOLANA (One sample per week) Column 6 of Table 1A (A) Calcined clay pozzolana

Date Fitness Lime Reactivity Compressive Strength at 28 Days Drying Shrinkage Max

Form-4-B : FLY ASH POZZOLANA (See Column 6 of Table 1 A)

SO2+ A1203 +Fe203

SiO2 MgO SO3

sulphur Na2O LOI Fineness

Lime reactivity

Compressive Strength

Drying Shrikage

Soundness Auto clave

Form-5: CLINKER (DAILY COMPOSITE SAMPLE) (See Column 6 of Table 1A)

Laboratory Ball-Mill Testing is required to be done when there is change in the source of Raw Material or change in design

Date of manuacture

Total loss of

Ignition

Insoluble Residue

SiO2 CaO AlO FeO SO MgO LSF Lime Saturation

Factor

Alunina Factor

Sample Pass/Fails

Disposal/ Action

taken if sample fails

Form-6-A: CLINKER GROUND WITH GYPSUM (Daily composite sample) (Note under Column 6 of Table 1 A)

Date of Grinding

Fineness Soundness AC - LC

Setting time IST - FST

Compressive Strength 3day- 7day- 28day

Sample Pass//fail

Disposal/Actio n taken if sample fails

Form-6-B: CLINKER GROUND WITH GYPSUM & POZZOLANA (Column 6 of Table I A)

Date of

Grinding

Fineness Soundness AC - LC

Setting time IST - FST

Compressive Strength 3day- 7day- 28day

Dry shrinkage

(Weekly)

Sample

Pass/fail

Disposal/Actio

n taken if

sample fails

Form-7: PORTLAND POZZOLANA CEMENT GRINDING/ BLENDING (Daily/Weekly Composite sample) (Column 5 of Table 1B)

Date of Grinding

Loss on Ignition

MgO Insoluble Material

SO3 Fineness Soundness Le-ch Auto Clave

Setting Time IST /FST

Compressive Strength 3 7 28 days

Drying Shrinkage (Weekly)

Sample Pass/Fail

Action taken if sample fails

Form-8: PORTLAND POZZOLANA CEMENT CRINDING (For Alternate hourly Samples) (Column 5 of Table 1B)

Date of

Grinding

Time at Fineness Setting Time

(IST)-(FST)

Sample

fail/pass

Mode of disposal/Action

taken if sample fails

Form-9: PORTLAND POZZOLANA CEMENT PACKING STAGE (Daily/Weekly Composite Samples) (Column 6 of Table 1B)

Date

of

Pcking

Loss

On

Igniti

on

MgO Insoluble

Materia

SO3 Chloride

Content

(Weekly

Fine

ness

Soundness

Le Auto

Ch Clav

Setting

time

IST-

FST

Compressive

Strength

3 7 28

days

Drying

Shrinkage

(Weekly)

Sample

Pass

/Fail

Mode of

disposal/Action

taken if

sample fails

Form-10: (See Clause 3 of STI)

S.No. Date Calibration Result of Calibration (Test records indicating details of standard values and observed values for

each equipment to be kept in proforma for which various columns be devised; as required)

Name of Equipment Action taken if equipment

found defective

Sl. No. (If any) Remarks

FREQUENCY OF CALIBRATION:

Blaine’s apparatus- Daily with licensee’ sown Standard cement sampleand once in a month with standard

cement samples supplied by NCCBM.

Compressive strength - Once in a month with licensee’s own proving ring and the proving ring shall be calibrated once

Testing machine in two years from the recognized calibrating agency like NPL/NABL accredited Lab or proving ring manufacturer having NPL certified calibrator.

Autoclave pressure gauge - Once in a six months either by licensee’s own dead weight Pressure gauge or from

approved independent agency /NABL accredited Lab or manufacturer of such

gauge having NPL certified calibrator. Vibration machine - Once in a month by licensee’s own tachometer. The tachometer shall be Calibrated once

in three Years from approved out Side agency /NABL accredited Lab having NPL

certified calibrator.

7

FLY ASH TESTING (physical- IS-1727) Lime reactivity Test Specimen: 50mm Age at testing: 10 day’s Temperature: 500C ± 20C Humidity (RH): 90 -100%

Material for mortar : = 1-hydrate lime : 2M*- pozzolana : 9- sand(3type)

M* = Specific gravity of pozzolana / Specific gravity of Lime Water requirement = Flow-70mm ± 5mm, 10 drop in 6 second.

IS require compressive St. = 4.5 N/mm2, min

Pozzolana Specific gravity = weight of pozzolana in gm / displaced volume in ml. Pozzolana min Blain = 320 Drying Shrinkage % max (IS) = 0.15 Molecular weight: CaCO3 =100, SiO2=60, Al2O3=102, Fe2O3 =160, MgO= 40, Na2O= 62, K2O = 94

C3S=228, C2S= 172, C3A= 270, C4AF= 486, CaSO4.2H2O =145

Chemical Composition: General IS-

code LOI SiO2 Al2O3 Fe2O3 CaO MgO Na2O

+K2O SO3 F /

CaO C3S C2S C3A C4AF

PPC 1489 5.0 31.0 4.5 3.5 43.0 5.0 1.4 -

Clinker 4032 0.5 21-22 5-6 3-5 62-65 3-6 .5-1.0 .2-.5 .5-2

Limestone 1760 34 12 2.4 1.6 43.0 3.8

Iron Ore

Gypsum 1288

Fly ash 3812 2-14 50-60 20-33 2-7 2-10 Min min

Rate of Clinker Phase on Properties of Cement:

C3A C3S C2S C4AF

Setting time Rapid Quick Slow -

Hydration Rapid Fast Slow Rapid

Early strength High-1day High-14 day Low -

Late strength - Less High -

Heat of

Hydration(cal/g)

207 120 62 100

Resistance to

Chemical attack

Poor Moderate High High

Dying Shrinkage - - low -

Alite C3S = Responsible for early Strength.

Belite C2S = Give ultimate (late) Strength along with alite.

Aluminate C3A = Contributes to early strength, Help faster setting, Liberates more heat in concrete

C4AF = Not contribution to Strength, Requited to reduce the burning Temperature for clinkerisation

Mostly occurs as a glassy interstitial phase.

Chemical analysis Type of analysis : 1 Gravimetric- IR,SO3,SiO2,R2O3 (Residual Oxide/3

rd group)

2 Volumetric- CaO, MgO (Fe2O3, Al2O3)

3 Spectroscopy 1.Flame Photo metter-K2O, Na2O (Uncoloured element)

2. UV-Spectro metter –TiO2, P2O5, MnO2, (Coloured & miner)

4 X-ray Method

Solution Prepare:

Normality: Equivalent weight / volume in letter.

Molaritiey: gm mole number / Volume in letter.

8

Lime Stone- TC & MC

Q.1 why multiply 1.786 for CaO?

Q.2 why multiply 2.09 for MgO?

Q.3 why multiply 0.84 for MC?

Take 50 ml HCL (0.4N)

in conical Flask

Add 1.0 gm lime stone

sample

Boil minimum 2min

Add Indicator-

Phynopthleen C20H14O4

Mwt-318.33,pH-8.2-9.8

Cool

Titrate with NaOH

(0.2N) slow titration

Take NaOH Burette

reading TC = 100-Burette reading

Add exis 10/20ml

NaOH (0.2N)

Boil about 1min.

Add Indicator-

Thymopthleen

Cool

Titrate with HCL (0.4N)

Fast titration

Take HCL Burette

reading MC = [Ex.NaOH-{2*HCL-BR}] X0.84

End point white to pink

colour

End point purple to white-

pink colour

Solution use:

= NaOH (0.2N)

40(Mwt)*0.2(N)*1000(ml)/1000= 8gm/L

= HCL(0.4N)

36.46(Mwt)*100/35.4(Purity)=87.28ml/L-1N =87.28ml/L-1N * 0.4 (Req.N)=34.91 ml/L

= Indicator dissolved in Alcohol

Calculation

CC = TC – MC

CaO = CC / 1.786

MgO = MC / 2.09

9

Cement- IR & SO3

Q.1 what is IR?

Material which is not reacts (dissolved) with Acid and basis.

Q.2 why multiply 34.3 for SO3?

Because So3 is found in BaSO4 Form

=(SO3/BaSO4)*100 = (80/137+32+64)*100 =(80/233)100 =0.3433*100 = 34.33

IR (max %) = X+4 (100-X) (Note: X= % of Fly ash)

100

1.0 gm cement sample

Dissolved 1:1 HCL

Only Heat 800C

Filter- 40 N. paper

Wash Hot water

Filtrate

Residue

Boil + add BaCl2 Wash with Na2CO3

Wash Hot water

Wash Hot water

Dryad in Oven

Ignited at 1000oC

Minim 30 min

Weight IR

Slowly Cool for ppt

form

Filter 42 N paper

Dryad in Oven

Ignited at 1000oC

Weight

Weight X 34.3 = SO3

Solution use: = 2N- Na2CO3= 10.6 gm sodium carbonate

dissolved in 100 ml distilled water

(Eq.wt = 53, Mwt 105.99 g/mol)

= 1:1 HCL = 50 ml HCL dissolved in 50 ml Distil water. (Mwt 36.46 g/mol)

= BaCl2 = 10 gm BaCl2 dissolved in 100 ml

distilled water.

For Acid reaction

For Basis reaction

IR=

Final weight-Initial weight

10

Clinker, Cement & Raw material (SiO2, R2O3)

All Raw materials & Cement Clinker Sample

Bake on Hot plate & cool it

Wash Crucible with H2O Filter with 40N paper

Add HCL (1:1), 20-30 ml

+Heat

0.5 gm sample in beaker

Add NH4Cl 2-3gm(mix well)

0.5 gm sample + Fusion mix.

In Platinum crucible

Fuse 1000oC for 1 hour

Add HCL (1:1), 20-30 ml

Add Con. HCL- 5ml,

Bake on Hot plate & cool it

Add HCL (1:1), 10-20 ml +

Distilled water + Heat

Filtrate Residue

Heat it +Add NH4Cl, 2-3gm

Heat it +Add NH4Cl 2-3gm

Wash with hot Distilled water

Boil it + Add HNO3 (1:1), 0.5ml

Add NH4OH (1:1)-ppt form

Dry (oven) + Ignite at 1000oC

Filter with 41N paper

SiO2= (F wt – I wt)*200

2 drop H2SO4 + 2 drop H2O

Add 20 ml HF

Put on Hot plate & dry

SiO2= (F wt – I wt)*200

Filtrate in 500ml

flask

paper

Residue

paper

R2O3= (F wt – I wt)*200

Dry (oven) + Ignite at 1000oC

CaO & MgO Process

next page

Use Solution: NH4OH(1:1) – 250 ml NH3 + 250 ml H2O HNO3 (1:1)- Fusion mix.= (Na2CO3+K2CO3)

Masking/

Oxidizing

agent

Reaction: = M SiO3 + 2HCl M Cl2 + H2SiO3 = H2SiO3 + Evaporation SiO2 + (H2O) = SiO2 + Impu. + 4HF SiF4 +2H2O H2SiO3 + 2H2 SiF6 = (FeCl3 + AlCl3) + 3NH4OH {Fe(OH)3 + Al(OH)3} + 3NH4Cl = {Fe(OH)3 + Al(OH)3} + Ignition Fe2O3 + Al2O3

For

Isolate

R2O3

11

Clinker, Cement & Raw material (CaO, MgO)-EDTA method

For-CaO For- MgO

(end colour red- pink to purple) (end colour red- pink to blue)

Take 20 ml aliquot solution

After filtrate R2O3 solution make up 500 ml

Add Tri ethanol amine (TEA)

5 ml (For Isolation), C6H15NO3,

Mwt-149.19 g/m

Add Glycerol 5 ml

(For Isolation), C3H8O3,

Mwt-92.10 g/m

Add Patton & Reader (P&R)

Indicator, C21H14N2O7S

Mwt-438.42 g/m

Add 10-20 ml Sodium (4.0N)

Hydroxide NaOH (For pH-12)

Mwt-00 g/m

Titrate with EDTA

(ethylene di amine tetra

acetate) Mwt-000 g/m

{0.0005608 X V1 X Vmu X 100} D.F.

Volume taken X Sample weight

= V1- EDTA Burette reading = Vmu- Volume make up = DF -

Take 20 ml aliquot solution

Add Tri ethanol amine (TEA)

5 ml (For Isolation), C6H15NO3,

Mwt-149.19 g/m

Add Glycerol 5 ml

(For Isolation), C3H8O3,

Mwt-92.10 g/m

Add Eriochrome black T (EBT)

Indicator, C20H2N3NaO7S

Mwt-461.38 g/m

Add 10-20 ml Buffer Solution

(For pH-10)

Mwt-000 g/m

Titrate with EDTA

(ethylene di amine tetra

acetate) Mwt-000 g/m

{0.0004032 X (V2- V1)X Vmu X 100} D.F.

Volume taken X Sample weight

= V1- EDTA Burette reading = V2- Cao titration BR = Vmu- Volume make up = DF -

Solution Use: = Buffer solution- 70 gm NH4Cl dissolved in 570 ml NH4OH. = 4.0N NaOH- 160 gm dissolved in 1000 ml H2O. =EDTA- 3.7224 gm dissolved in H2O 100 ml and make up 1000 ml solution.

Reaction: = CaCl2 +(NH4)2C2O4 CaC2O4 +2NH4Cl = CaC2O4 + H2O CaC2O4.H2O CaO +CO2 +CO =

12

Iron (Raw material) -Dichromate method

Clinker sample

0.5 gm sample + Fusion mix. In

Platinum crucible

Fuse in 1000oC minimum 30

min

Cool and wash Pt. crucible with

1:1 HCl

Wash crucible with Distilled

water

0.5 gm clinker sample dissolved

in HCl -1:1

Boil & add SnCl2 Drop wise till

colourless solution

Completely cool (Room Temp.)

Add Barium di phenol Salfonate

(BDS) Indicator

Add 5-10 ml HgCl2 and Acid

mixture –Masking agent

Titrate with K2Cr2O7 Potassium

dichromate

Iron= B.R X Factor (K2Cr2O7)

Solution Preparation: =Acid mix.- 1 H2SO4+1 HCL +3 H2O = K2Cr2O7 – = BDS – = SnCl2 – = Fusion mix -

Reaction: = 2Fe3+ + Sn2+ 2Fe2+ + Sn4+ = 2Fe2+ + K2Cr2O7 2Fe3+

13

Free Lime in Clinker

Reaction Occurring in Pre heater to kiln:

1. Evaporation of free water - 100oC

2. Release of combine water from clay - 500oC

3. Dissociation of magnesium carbonate - 900oC

4. Dissociation of Calcium carbonate - above 900oC

5. Dissociation of lime and clay - 900oC-1200

oC

6. Commencement of liquid formation - 1200oC-1280

oC

7. Further formation of liquid and completion - above 1280oC

Of clinker compound

Phase of Clinker formation:

It is know that fuel economy or improved burnability in the formation of clinker can be effected

through the following stage of clinker burning.

= Formation of 2CaO.Fe2O3 :- 800oC

= Formation of 2CaO.Fe2O3.CaO.Fe2O3 :-900oC

= Formation of 2CaO.SiO2+2CaO.Al2O3 :-1000oC

SiO2+Ferrite Phase

= Formation of 2CaO.SiO2, 5CaO.3(Al2O3) :-1100oC

5CaO.Al2O3, 3CaO.SiO2, Ferrite Phase

= Formation of 2CaO.SiO2, 3CaO.SiO2 :-1200oC

12CaO.7Al2O3, SiO2+2CaO.Fe2O3, 3CaO.SiO2,

Take 0.1 gm Clinker sample in

beaker

Add 10 ml Ethylene Glycol

Put for 45 min in water bath

Filter with 40N paper

Filtrate

Residue out

Add Bromocrsol Grate Green

Indicator

Titrate with 0.1N HCL

hcl

End Colour –Green to golden

Yello

hcl

F/CaO= B.R X 0.28

hcl

Solution Preparation:

14

= Formation of 3CaO.Al2O3, 3CaO.SiO2 :-1300oC

2CaO.SiO2 + Ferrite Phase

= Formation of 3CaO.Al2O3, 3CaO.SiO2 :-1400oC

2CaO.SiO2+ Ferrite Phase

Effects of Various Factors on Raw mix Burnability:

Characteristic

/Modulus

Limiting

range

Preferable

range

Effects

Silica modulus

(SM) 1.9-3.2 2.3-2.7

If SM High

Result in hard burning, high fuel consumption,

difficulty in coating formation, radiation from shell

is high, deteriorates the kiln lining

Alumina

modulus (AM) 1.5-2.5 1.3-1.6

If AM High

Impacts harder burning, high fuel consumption,

Increases C3A decreases C4AF, reduces liquid phase

& kiln output, if AM is too low and raw mix is

without free silica, clinker sticking and balling is too

high.

Lime

saturation

factor (LSF)

0.66-

1.02 0.92-0.96

A higher LSF

Make it difficult to burn raw mix, increases C3S,

reduces C2S, deteriorates refractory lining, increases

radiation from shell, increases kiln exit gas

temperature.

Free silica 0-3 As low as

possible

A higher silica

Increases fuel and power consumption, causes

difficulty in coating formation, deteriorates

refractory, increases radiation of heat kiln shell,

MgO 0-5 0-3

A higher MgO

Favours dissociation of C2S and CaO and lets C3S

form quickly, tends the balling easy in the burning

zone and affects kiln operation.

Alkalies 0-1 0.2-0.3%

A high alkali

Improves burnability at lower temperature &

deteriorates at higher, increase liquid content and

coating formation, lowers the solubility of CaO in

melt, breaks down alite & belite phases, creates

operational problem due to external & internal cycle.

Sulphur

compound 0-4 0.5-2%

A higher Sulphur compound

Acts as an effective mineraliser and modifier of

alkali cycle by forming less volatiles,

Fluorides 0-0.6 0.03-

0.08%

A higher fluorides

Leads to modify the kinetic of all burning reaction ,

lowers the temperature of C3S formation by 150-200

Chlorides 0.06 Up to

0.015%

A higher chlorides

Higher Cl forms more volatiles % causes operational

problem due to its complete volatilization in burning

zone, increases liquid formation & melting point of

the absorbed phase is drastically change.

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short note of cement chemistry

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