Utilization of Coal Slurry Waste as an Alternative Raw...

Mustafa Ziypak, Zeki Olgun, Mustafa Turan, Julide Erdogan, Yasemin Kilic, Aylin Sahin, Mustafa Kara

5th International Conference on Sustainable Solid Waste Management, 21–24 June 2017, Athens

Utilization of Coal Slurry Waste as an Alternative Raw Material in Portland

Cement Clinker Production

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Outline

2

Coal Slurry Waste

Cement Manufacturing

Raw Material Characterization

Laboratory Scale Clinker Production

Industrial Scale Clinker Production

Results & Discussion

Objective

The aim of this study is investigate the potential usage of Turkish

Coal Enterprises (TCE) coal slurry waste as an alternative raw

material in laboratory and industrial scale Portland cement clinker

production.

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Coal slurry waste Portland cement clinker

Coal Slurry Waste

4

• Coal is produced from underground

and open pit mines and then it is

washed in the coal washing plant.

• After washing process, the obtained

liquid coal waste is named as

“coal slurry”

• Coal slurry contains clay minerals

(~70%) together with coal.

• Coal slurry wastes usually stored at

the waste dams.

TCE Omerler Coal Washing Plant

Coal slurry waste stored at the waste dams

Cement

Cement is a hydraulic binder.

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Cement Raw Materials• Limestone• Clay• Shale• Sand• Bauxite• Iron ore

clay

limestone

iron ore

bauxite

shale

Sand

Cement

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Cement Manufacturing Process

1. Blasting: The raw materials are blasted from the quarry.

2. Raw Material Transport: The raw materials are loaded into a dumper.

3. Crushing, Transportation and Homogenization: The raw materials are crushed, transported to

the plant and then homogenized.

4. Raw Grinding: The raw materials are very finely ground in order to produce the raw meal.

5. Burning: The raw meal is burnt at 1450°C to produce clinker (basic material to make cement).

6. Grinding: The clinker and gypsum are very finely ground to obtain a ‘pure cement’.

7. Storage, Packing, Dispatch

Experimental Study

Coal Slurry Waste

• Coal slurry waste samples were taken

from the upper stream of multi gravity

seperator at coal washing plant.

• It was determined that coal slurry waste

contains 80 % moisture.

• These samples were dried at drying oven

to remove the moisture .

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Turkish Coal Enterprises : Coal Slurry Waste

Laboratory Scale Clinker Production Studies

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• Determination of Moisture• Calorific Analysis• Wet Chemical Analysis• Mineralogical Analysis• Grain Size Distribution• Burnability Index Test

Raw Material Characterization


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% MoistureCoal Slurry Waste (dried sample) 2.20

Raw Meal 0.5

• Max 20% moisture content is more suitable for cement production process.

• Thus, coal slurry was dried for cement production.


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Analysis Unit

Analysis Results

MethodOriginalbased

(obtainedspecimen)

At dry basisin air

(moistureremoved at

35ºC)

At dry basis(moisture

completelyremoved)

Moisture wt. % 71.73 1.87 - ASTM D 7582-15

Ash wt. % 20.56 71.37 73.00 ASTM E 1755-15

Volatile Matter wt. % 5.44 18.88 19.23 ASTM D 7582-15

Fixed Carbon wt. % 2.27 7.88 17.00 ASTM D 3172-13

Total Sulphur wt. % 0.19 0.66 0.67 ASTM D 4239-14

Lower CalorificValue kcal/kg Negative

value 1102 1134ASTM D 5865-13

ISO 1928-09Higher CalorificValue kcal/kg 340 1180 1203 ASTM D 5865-13

Calorific Analysis for Laboratory Scale Studies


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Chemical composition of raw materials (wt. %)

Compound Raw Meal (%) Coal Slurry Waste (%)

SiO2 12.96 42.7

Al2O3 3.38 12.8

Fe2O3 2.13 5.2

CaO 42.90 1.5

MgO 1.22 3.1

Na2O 0.26 0.2

K2O 0.45 1.4

TiO2 0.25 0.5

SO3 0.03 1.4

P2O5 0.07 0.5

MnO 0.0395 0.08

Cr2O3 0.024 0.07

Cl 0.011 0.02

Loss on ignition (LOI) 35.5 30.3

Humidity (%) 0.5 2.20

CaCO3 (%) 77.2 2.79


Mineralogical composition of raw materials

Raw Meal Coal Slurry Waste

Calcite, CaCO3 Magnesite, MgCO3

Quartz, SiO2 Quartz, SiO2

Dolomite, CaMg(CO3)2 Dolomite, CaMg(CO3)2

Feldspar, (K,Na)AlSiO3O8 Kaolinite, Al2Si2O5(OH)4

Chlorite, (Mg,Al,Fe)6(Si,Al)4O10(OH)8 Clinochlore, (Mg,Fe)6(Si,Al)4O10(OH)8

Muskovite, (K,Na)Al2(Si,Al)4O10(OH)2 Illite, (K,H3O)Al2Si3AlO10(OH)2

Anhydrite, CaSO4

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13

In order to see the effect of coal slurry waste addition,

the burnability index of 3 mixtures were compared at

laboratory scale study:

1st mixture Reference raw meal of CIMSA Cement Factory

2nd mixture 2 wt. % coal slurry waste addition to the reference raw meal

3rd mixture 3 wt. % coal slurry waste addition to the reference raw meal


Burnability Index

B.I. ≤ 83 Easy burnability

83 ≤ B.I. < 120 Normal burnability

B.I. ≥ 120 Hard burnability

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RawMeal

CoalSlurryWaste

1400oC 1450oC 1500oC BurnabilityIndex RESULT

% % Free CaO FreeCaO

FreeCaO B.I.

Raw Meal 100.00 -- 3.70 2.97 2.16 117.34 Normal Burnability

Coal SlurryWaste

98 2 1.84 1.70 1.44 68.83 EasyBurnability

97 3 1.55 1.43 0.83 49.98 EasyBurnability

BURNABILITY INDEX (B.I.)= 100*(F.CaO1400°C/3.6 + F.CaO1450°C/2.6 + F.CaO1500°C/1.6) / 3

2 wt. % and 3 wt. % coal slurry waste addition to the raw meal make the

burnability easier than reference raw meal.

Industrial Scale Experimental Studies

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Industrial Scale Raw Material Characterization

• Studies are carried out in CIMSA Inc. Eskişehir Cement Company

• Turkish Coal Enterprises Company sent approximately 500 tons of dried coal slurry waste to

CIMSA Inc.

The chemical composition of each raw material

Compound Limestone (%) Shale (%) Sand (%) Bauxite (%) Iron source (%) Raw Materials Mix (%)

SiO2 3.16 44.40 82.57 10.30 28.4 15.58

Al2O3 0.65 11.17 5.53 50.90 5.71 3.66

Fe2O3 0.29 9.93 5.10 24.02 54.63 1.81

CaO 53.15 15.20 0.58 3.03 0.70 42.24

MgO 0.33 6.10 0.28 0.65 0.57 1.32

SO3 0.09 0.14 0.04 0.28 0.28 0.029

Cl- 0.006 0.004 0.001 0.001 0.002 0.001

Na2O 0.014 1.46 0.032 0 0.04 0.13

K2O 0.43 0.30 0.64 0.44 0.30 0.44

LOI 41.9 10.8 5.1 10.2 9.4 34.6

TOTAL 100.02 99.504 99.873 99.821 100.032 99.81

H2O 2.4 6.5 11.5 4.7 13.6 5.6

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Industrial Scale Raw Material Characterization Studies

17

Calorific Analysis for Industrial Scale Studies

Analysis Unit

Analysis Results

MethodOriginalbased

(obtainedversion of specimen)

At dry basis in air (moistureremoved at

35°C)

At dry basis(moisture

completelyremoved)

Moisture wt.% 12.54 2.84 - ASTM D 7582-15

Ash wt.% 62.50 69.43 71.46 ASTM E 1782-15

Volatile Matter wt.% 17.20 19.11 19.67 ASTM D 7582-15

Fixed Carbon wt.% 7.76 8.62 8.87 ASTM D 3172-13

Total Sulphur wt.% 0.82 0.91 0.93 ASTM D 4239-14e2

Lower CalorificValue kcal/kg 1155 1344 1400

ASTM D 5865-13

ISO 1928-09

Higher CalorificValue kcal/kg 1293 1436 1478 ASTM D 5865-13

Industrial Scale Raw Meal Production Studies

Raw meal mix composition (wt. %)

Limestone + Clay

(Mix) (wt. %)

Limestone

(wt. %)

Feldspar

(wt. %)

Iron source

(wt. %)

Coal Slurry

Waste (wt. %)

87.17 11.83 0 0 1.00

79.20 15.58 2.40 0.72 2.10

78.84 15.24 2.31 0.56 3.05

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• In raw meal production, raw mix, limestone and coal slurry waste materials were used in the average percentages as given below:

Raw Meal Production with Using Coal Slurry Waste

Industrial Scale Raw Meal Production Studies

3 different kinds of coal slurry waste containing raw meal produced and chemically analyzed.

The chemical compositions of coal slurry waste containing raw meal

Compound

Coal Slurry Waste Containing Raw MealsCIMSA Raw Meal

(%)1 wt. %

Coal Slurry Waste

2 wt. %

Coal Slurry Waste

3 wt. %

Coal Slurry Waste

Al2O3 3.40 3.17 3.31 3.07

CaO 43.13 42.99 43.02 42.81

Cl- 0.007 0.007 0.006 0.007

Fe2O3 2.24 2.28 2.29 2.09

K2O 0.41 0.45 0.45 0.47

MgO 1.29 1.53 1.28 1.55

Na2O 0.16 0.28 0.2 0.26

SiO2 12.76 12.38 12.56 12.72

SO3 0.34 0.29 0.32 0.14

LOI 35.3 35.8 35.7 35.90

TOTAL 99.037 99.17 99.14 99.01

Lime Saturation Factor

(LSF) (%)104.65 107.8 106.1 105.46

Silica Ratio (SR) 2.26 2.27 2.24 2.46

Alumina Ratio (AR) 1.52 1.39 1.45 1.47 19

Industrial Scale Clinker Production Studies

In clinker production,

the feed rate of raw meal to rotary kiln is 130-140 ton/hour,

calcination ratio 94-96 %

Clinker production in rotary kiln 20

Industrial Scale Clinker Production Studies

Clinker produced from2 wt.% coal slurry waste

containing raw meal


containing raw meal


containing raw meal21

Region where the clinker sample is

taken

Industrial Scale Clinker Characterization Studies

Density determination:

• In general, density values are desired between 1200-1300 g/l.• If this value is less than 1200 g/l, it can be said that, clinker indicates free

lime.

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CIMSA Inc. reference (original) clinker 1250 g/l1 wt. % coal slurry waste substituted clinker 1230 g/l2 wt. % coal slurry waste substituted clinker 1230 g/l3 wt. % coal slurry waste substituted clinker 1210 g/l


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CLINKER

Modules1 wt.%

Coal Slurry

Waste

2 wt.%

Coal Slurry

Waste

3 wt.%

Coal Slurry

Waste

Desired

Limit Values

(%)

CIMSA Inc.

Average

Values (%)Lime Saturation Factor

(LSF)95.81 97.9 96.6 92 – 96 97.40

Silica Ratio (SR) 2.35 2.39 2.39 2.3 – 2.7 2.44

Alumina Ratio (AR) 1.60 1.6 1.61 1.3 – 1.6 1.53

Hydraulic Module (HM) 2.16 2.41 2.18 1.7 – 2.2 2.20


Main Compounds of Clinker Produced with Coal Slurry Waste

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CLINKER

Main Phase1 wt.% Coal Slurry

Waste

2 wt.% Coal

Slurry Waste

3 wt.% Coal

Slurry Waste

CIMSA Inc.

Average Values (%)

C3S 57.53 57.72 64.76 55-65

C2S 19.80 16.43 11.98 11-20

C3A 8.16 8.6 8.72 7-9

C4AF 10.37 10.25 10.36 10-15

Mineral Phase Chemical Formula Symbol

Tricalcium silicate (Alite) 3CaO.SiO2 C3S

Dicalcium silicate (Belite) 2CaO.SiO2 C2S

Tricalcium aluminate (Celite) 3CaO.Al2O3 C3A

Tetracalcium aluminoferrite (Ferrite) 4CaO.Al2O3.Fe2O3 C4AF

Cement Production Studies

At the end of the study,

• 95 wt. % clinker (produced with using coal slurry wastes) and

5 wt. % gypsum (CaSO4.2H2O) were mixed and milled together.

Finally, with water addition, CEM I 42.5 R type cement was

produced.

• Physical and mechanical properties desired in the cement

products were determined according to the TS EN 197-1

(2012) standard.

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• Coal slurry waste was evaluated as raw materials for Portland

cement clinker production.

• The addition of 2 wt. % and 3 wt. % coal slurry waste to the raw meal

make the burnability easier than reference raw meal.

• In cement production, high volatile material content reduces the

capacity of clinker production because of volume decreasing during

the raw meal calcination stage. Due to the fact that coal slurry waste

contains high volatile matter ratio (30 %), carbon content within the

coal slurry waste should be reduced as possible.

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• For successfully using in the cement production, coal slurry waste

should not contain any calorific value and has lower than 20 %

moisture content as possible. So, the moisture of coal slurry waste

must be dewatering.

• According to results of all experimental studies, coal slurry waste up

to 3 wt. % addition in clinkers showed acceptable phase

compositions and the major phases which are comparable with

CIMSA Inc. Portland cement clinker.

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This study was funded by the Turkish Coal Enterprises. The authors are thankful to the

CIMSA Incorporation for the technical support in laboratory and industrial scale clinker

productions.

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Thank youPh.D. Mustafa KARA

TUBITAK MARMARA RESEARCH CENTERPK 21, 41470 GEBZE-KOCAELİ

Tel: +90-262-677 30 33Faks: +90-262-641 23 09

[email protected]://www.mam.gov.tr 29

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