CEE April-June 2012

1. Introduction: Cement manufacturing is an energy-intensive process. The global cement industry consumed about 9 exajoules (EJ) of fuels and electricity for cement producticn. Cement manufacturing consumes a variety of naturally occurring raw materials such as limestone, clay, shale, sand, iron ore, and gypsum as the main ingredients. In order to conserve non-renewable raw materials, cement companies are using alternative materials as a replacement for traditional materials. Alternative materials such as industrial wastes/ by-products are being generated in abundance as a result of growing industrialization across the globe. This paper discusses the alternative raw materials which can be utilized advantageously for cost– effectiveness as well as for reduction in carbon dioxide (C0 2 ) emissions in cement manufacturing process. More specifically, this paper highlights the successful exploitation of Copper slag, Flue Dust, and Spent Pot-liners in place of conventional corrective materials such as bauxite & laterite in Cement manufacture. The potential uses of Jarosite, a by-product of Zinc manufacture, are also discussed. 2. Materials Used: 2.1: Copper Slag: While producing Copper Anode, a Slag rich in Iron and fair amount of Sili ca is generated. For every ton of copper produced approximately 2.5 tons of copper slag is generated. In India the amount of Copper slag produced is reported to be about 1.3 MT per annum with an accumulated stock of about 4 MT.[1,2]. In the present work Copper Slag was obtained from Sterlite Industries, Tuticorin. 2.2: Flue Dust: Flue dust is a fine powder generated in the Blast Furnace while making pig iron from iron ore. This material was collected from M/S. Jindal Steel Works, near Salem, Tamil Nadu. Flue dust was evaluated as a substitute for conventional iron ore. 2.3: Spent Pot Liner: Spent Pot Liner (SPL) is a waste product generated in Aluminium industry. This is the conductive carbon used to line the pots in the electrolytic process that separates elemental aluminium from alumina raw material. SPL is usually made up of two layers, a conductive carbon layer and a non-conductive insulation layer. A sample of this SPL and associated brick liner was collected and examined for use as Alternate Fuel & Raw material in cement manufacture. 2.4 Jarosite: . During the metallic zinc extraction step, zinc industries are producing significant quantities of solid fine residues as a waste in the form of jarosite. This waste consists mainly of iron, sulphur, zinc, with minor amounts lead , cadmium and other metallic and non-metallic oxides. Jarosite was obtained from the Hindustan Zinc limited (HZL), Debari Rajasthan, 3. Methodology: All the samples were subjected to chemical analysis by both conventional wet chemical methods as well as by XRF technique . Mineralogy of the samples was examined with Philips X'Pert Pro XRD using High Score+ software. Thermal analysis was carried out using Netzsch Simultaneous Thermal Analyzer Model STA 400. Particle size distribution was analysed using Malvern Particle Size Analyzer Model 2000S. Microstructural examination was carried out with Leica Optical Microscope fitted with image analyser. Burnability studies were conducted following standard procedures and Cement testing was carried out as per BIS-4031. 4. Results & Discussions: 4.1: Copper Slag & Flue Dust as Iron Ore substitutes in Cement Making: Both Copper Slag and Flue Dust are intended for use as replacement materials in place of conventional iron ore in the cement raw mix composition. The chemical analysis of the Copper slag & Flue Dust are given in Table-1 and the XRD of the same are presented in Fig-1 &2. For comparison, the composition of Iron ore is also given Table:1 Chemical composition of Granulated Copper Slag. Material SiOz Ab03 Fc20 3 CaO MgO LOt Na20 K20 Iron Ore 18.1 9.5 65.2 0.4 0.3 5.8 0.5 0.2 Copper Slag 28.7 3.6 64.1 1.1 0.6 6.1* 0.3 0.6 Flue Dust 12.4 8.0 64.5 1.9 1.2 9.2 0.6 0.4 • Gain On Ignition 6