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

Transcription

1 Utilization of Coal Slurry Waste as an Alternative Raw Material in Portland Cement Clinker Production Mustafa Ziypak, Zeki Olgun, Mustafa Turan, Julide Erdogan, Yasemin Kilic, Aylin Sahin, Mustafa Kara 5th International Conference on Sustainable Solid Waste Management, June 2017, Athens 1

2 Outline Coal Slurry Waste Cement Manufacturing Raw Material Characterization Laboratory Scale Clinker Production Industrial Scale Clinker Production Results & Discussion 2

3 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. Coal slurry waste Portland cement clinker 3

4 Coal Slurry Waste 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 TCE Omerler Coal Washing Plant Coal slurry contains clay minerals (~70%) together with coal. Coal slurry wastes usually stored at the waste dams. Coal slurry waste stored at the waste dams 4

5 Cement bauxite Cement is a hydraulic binder. clay limestone iron ore Cement Raw Materials Limestone Clay Shale Sand Bauxite Iron ore Sand shale 5

6 Cement 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 6

7 Experimental Study Turkish Coal Enterprises : 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. Coal Slurry Waste 7

8 Laboratory Scale Clinker Production Studies Raw Material Characterization Determination of Moisture Calorific Analysis Wet Chemical Analysis Mineralogical Analysis Grain Size Distribution Burnability Index Test 8

9 Laboratory Scale Clinker Production Studies Max 20% moisture content is more suitable for cement production process. Thus, coal slurry was dried for cement production. % Moisture Coal Slurry Waste (dried sample) 2.20 Raw Meal 0.5 9

10 Laboratory Scale Clinker Production Studies Calorific Analysis for Laboratory Scale Studies Analysis Results Analysis Unit Original based (obtained specimen) At dry basis in air (moisture removed at 35ºC) At dry basis (moisture completely removed) Method Moisture wt. % ASTM D Ash wt. % ASTM E Volatile Matter wt. % ASTM D Fixed Carbon wt. % ASTM D Total Sulphur wt. % ASTM D Lower Calorific Value Higher Calorific Value kcal/kg Negative value ASTM D ISO kcal/kg ASTM D

11 Laboratory Scale Clinker Production Studies Chemical composition of raw materials (wt. %) Compound Raw Meal (%) Coal Slurry Waste (%) SiO Al 2 O Fe 2 O CaO MgO Na 2 O K 2 O TiO SO P 2 O MnO Cr 2 O Cl Loss on ignition (LOI) Humidity (%) CaCO 3 (%)

12 Laboratory Scale Clinker Production Studies Mineralogical composition of raw materials Raw Meal Coal Slurry Waste Calcite, CaCO 3 Magnesite, MgCO 3 Quartz, SiO 2 Quartz, SiO 2 Dolomite, CaMg(CO 3 ) 2 Dolomite, CaMg(CO 3 ) 2 Feldspar, (K,Na)AlSiO 3 O 8 Kaolinite, Al 2 Si 2 O 5 (OH) 4 Chlorite, (Mg,Al,Fe) 6 (Si,Al)4O 10 (OH) 8 Clinochlore, (Mg,Fe) 6 (Si,Al) 4 O 10 (OH) 8 Muskovite, (K,Na)Al 2 (Si,Al) 4 O 10 (OH) 2 Illite, (K,H 3 O)Al 2 Si 3 AlO 10 (OH) 2 Anhydrite, CaSO 4 12

13 Laboratory Scale Clinker Production Studies In order to see the effect of coal slurry waste addition, the burnability index of 3 mixtures were compared at laboratory scale study: 1 st mixture Reference raw meal of CIMSA Cement Factory 2 nd mixture 2 wt. % coal slurry waste addition to the reference raw meal 3 rd mixture 3wt. %coal slurry waste addition to the reference raw meal 13

14 Laboratory Scale Clinker Production Studies Burnability Index BURNABILITY INDEX (B.I.)= 100*(F.CaO 1400 C /3.6 + F.CaO 1450 C /2.6 + F.CaO 1500 C /1.6) / 3 B.I. 83 Easy burnability 83 B.I. < 120 Normal burnability B.I. 120 Hard burnability Raw Meal Coal Slurry Waste % % Free CaO 1400 o C 1450 o C 1500 o C Burnability Index Free CaO Free CaO Raw Meal Coal Slurry Waste B.I wt. % and 3 wt. % coal slurry waste addition to the raw meal make the burnability easier than reference raw meal. RESULT Normal Burnability Easy Burnability Easy Burnability 14

15 Industrial Scale Experimental Studies 15

16 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 (%) SiO Al 2 O Fe 2 O CaO MgO SO Cl Na 2 O K 2 O LOI TOTAL H 2 O

17 Industrial Scale Raw Material Characterization Studies Calorific Analysis for Industrial Scale Studies Analysis Unit Original based (obtained version of specimen) Analysis Results At dry basis in air (moisture removed at 35 C) At dry basis (moisture completely removed) Method Moisture wt.% ASTM D Ash wt.% ASTM E Volatile Matter wt.% ASTM D Fixed Carbon wt.% ASTM D Total Sulphur wt.% ASTM D e2 Lower Calorific Value kcal/kg ASTM D ISO Higher Calorific Value kcal/kg ASTM D

18 Industrial Scale Raw Meal Production Studies Raw Meal Production with Using Coal Slurry Waste In raw meal production, raw mix, limestone and coal slurry waste materials were used in the average percentages as given below: Raw meal mix composition (wt. %) Limestone + Clay Limestone Feldspar Iron source Coal Slurry (Mix) (wt. %) (wt. %) (wt. %) (wt. %) Waste (wt. %)

19 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 Meals 1wt.% 2wt. % 3 wt. % Coal Slurry Waste Coal Slurry Waste Coal Slurry Waste CIMSA Raw Meal (%) Al 2 O CaO Cl Fe 2 O K 2 O MgO Na 2 O SiO SO LOI TOTAL Lime Saturation Factor (LSF) (%) Silica Ratio (SR) Alumina Ratio (AR)

20 Industrial Scale Clinker Production Studies In clinker production, the feed rate of raw meal to rotary kiln is ton/hour, calcination ratio % Clinker production in rotary kiln 20

21 Industrial Scale Clinker Production Studies Clinker produced from 1 wt.% coal slurry waste containing raw meal Region where the clinker sample is taken Clinker produced from 2 wt.% coal slurry waste containing raw meal Clinker produced from 3 wt.% coal slurry waste containing raw meal 21

22 Industrial Scale Clinker Characterization Studies Density determination: In general, density values are desired between g/l. If this value is less than 1200 g/l, it can be said that, clinker indicates free lime. CIMSA Inc. reference (original) clinker 1250 g/l 1 wt. % coal slurry waste substituted clinker 1230 g/l 2 wt. % coal slurry waste substituted clinker 1230 g/l 3 wt. % coal slurry waste substituted clinker 1210 g/l 22

23 Industrial Scale Clinker Characterization Studies Modules 1 wt.% Coal Slurry Waste 2 wt.% Coal Slurry Waste CLINKER 3 wt.% Coal Slurry Waste Desired Limit Values (%) CIMSA Inc. Average Values (%) Lime Saturation Factor (LSF) Silica Ratio (SR) Alumina Ratio (AR) Hydraulic Module (HM)

24 Industrial Scale Clinker Characterization Studies Main Compounds of Clinker Produced with Coal Slurry Waste CLINKER Main Phase 1 wt.% Coal Slurry Waste 2 wt.% Coal Slurry Waste 3 wt.% Coal Slurry Waste CIMSA Inc. Average Values (%) C 3 S C 2 S C 3 A C 4 AF Mineral Phase Chemical Formula Symbol Tricalcium silicate (Alite) 3CaO.SiO 2 C 3 S Dicalcium silicate (Belite) 2CaO.SiO 2 C 2 S Tricalcium aluminate (Celite) 3CaO.Al 2 O 3 C 3 A Tetracalcium aluminoferrite (Ferrite) 4CaO.Al 2 O 3.Fe 2 O 3 C 4 AF 24

25 Cement Production Studies At the end of the study, 95 wt. % clinker (produced with using coal slurry wastes) and 5 wt. % gypsum (CaSO 4.2H 2 O) 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 (2012) standard. 25

26 Results & Discussion 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. 26

27 Results & Discussion 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. 27

28 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. 28

29 Thank you Ph.D. Mustafa KARA TUBITAK MARMARA RESEARCH CENTER PK 21, GEBZE-KOCAELİ Tel: Faks: