Cement Energy and Environment

Table 6: Chemical analysis of bulk clinkers Oxide constituents Percenta~e CL-C ' CL-5 LOI 0.87 0.97 GaO 64.60 64.44 Si02 23.51 22.50 AI20 3 4.14 4.27 Fe20 3 3.93 3.90 MgO 1.82 1.72 S03 0.37 0.79 Na20 0.32 0.37 K20 0.12 0.15 Chloride 0.018 0.01 Insoluble residue 0.52 0.39 3.7 Performance evaluation of OPC samples Ordinary Portland cement samples OPC-C and OPC-5, prepared using bulk control clinker CL-C and mineralized clinker CL-5, was investigated for physical properties such as consistency, setting time, compressive strength at 3, 7 and 28 days and soundness. The Blaine's fineness of cements OPC-C and OPC-5 were maintained at 300±20 m 2/kg (Table 7). The water requirement to prepare consistent paste of both samples was found to be 26.5%. The initial and final setting times of cement OPC-5 was found to be comparable to control cement. Compressive strength of cement OPC-5 at 3, 7 and 28 days were found to be marginally higher as compared to control cement OPC-C. An increase in compressive strength of cement OPC-5 could be attributed to improved alite formation and development of fine grained alite and belite phases resu lting in improvement in their reactivity. The results of soundness showed high dimensional stability of resultant cement. Therefore, the results of physical characteri stics of cement OPC-5 prepared with addition of 1.5% jarosite in raw mix showed marginal improvement in compressive strength at all ages as compared to the control counterpart, OPC-C and fulfilled all I Table 7: Physical performance of cement samples Physical OPC-C OPC-5 15:269- Properties 2015 Blaine's 290 294 ~225 fineness (m 2/kg) Consistency (%) 26.5 26.5 Setting time (minutes) Initial (1ST) 130 135 ~30 Final (FST) 180 190 ~600 Compressive Strength (MPa) 3 days 25 26 ~23 7 days 34 36 2:33 ·- 28 days 47 49 ~43 and ~58 Soundness Le-Chaterlier 2.0 2.0 ~10 .0 (mm) Autoclave (%) 0.05 0.04 ~0.8 CONCLUSIONS 1. The presence of iron, sulphate, alkalis and zinc etc in by-product jarosite sample showed its compatibility to influence the burning characteristics of cement raw mixes. 2. Burnability studies of cement raw mixes prepared using coarse grained calcite and quartz limestone and different doses of jarosite has shown improvement in lime assimilation and free lime content decreased with increasing doses of jarosite. 3. Clinker sample CL-5 obtained with 1.5% dose of jarosite showed formation of fine grained alite and belite phases as compared to control clinker CL-C. 4. The physical characteristics of cement sample OPC-5 prepared from mineralized clinker CL-5 showed slight improvement in compressive strength at all ages. 5. Use of jarosite in the manufacture of OPC can thus result in improved quality of clinker along with gainful utilization of industrial by-product jarosite leading to environmental sustainability. ACKNOWLEDGEMENT The work reported in this paper forms a part of study sponsored by M/s Binani Zinc Limited, Kochi , Kerala, India under the programme of waste utilization. The authors are thankful to the requirements of Indian Standard IS: 269-201 5 Director General, NCB for allowing publication of described for OPC-43 grade cement. the paper. 16 ...