Cement Energy and Environment

.. " , Clinker Mineralization Using By-Product 'Jarosite' S K Agatwal, S Harsh, S K Chaturvedi, Ashwani Pahuja National Council for Cement and Building Materials, Ballabgarh, Haryana, India Key Words: Jarosite, free lime, clinker phases, microstructure, mineralizing effect compressive strength Abstract Many of the industrial by-products contain significant amount of elements which can substantially affect the clinkerization reaction and behave as mineralizer leading to production of energy effective clinker. Jarosite, a by-product of zinc industry contains iron, sulphur, alkalis and zinc bearing mineral phases, and can therefore be a useful additive in the manufacture of cement particularly for hard burnt raw mix. Different cement raw mixes were designed incorporating 0.25 to 2.0 wt.% jarosite, maintaining clinker parameters for OPC and fired at the temperature of 1400 and 1450°C. The addition of jarosite improves its burnability with increase in alite formation associated with development of fine grained alite and belite. The compressive strength of OPC prepared using optimized 1.5 wt.% dose of jarosite showed marginal increase in strength development as compared to control counterpart. 1.0 Introduction Many of the industrial wastes and by-products contain significant amount of elements other than usual oxides of calcium, silica, alumina, iron etc, which can substantially affect the clinkerization reaction and behave as mineralizer leading to conservation of natural resources and energy. Only small amount of these elements can extensively change the properties of the melt in terms of reactivity and burnability of cement raw mix, clinker phase development, microstructure and properties of cement thus prepared. [Moir and Glasser, 1992] reported the mineralizing effect of addition of fly ash, BF slag , iron oxide, silica sand etc in cement manufacturing. Studies showed the mineralizing effect of industrial by-products such as copper slag [Ali et al. 2013; Agarwal et.al. , 2009; Alp et.al 2008; Medina et.al. 2006], jarosite [Agarwal et.al 2015, Agarwal et.al 2014, Ali et. al., 2014; Agarwal et.al . , 2011], LD slag [Sahu et.al 2015], oil based mud (OBM) cutting waste [Hilal AI-Dhamri et.al 2015], by-products from aluminium industry [Menendez et al 2015, Zimmermann et al 2015, Konik et.al . 1997], low grade fluorspar [Ghosh and Mohan, 1997], waste ammunition material (WAM) containing Cu , Pb, Sn and Zn [Kolovos,2006] , phosphogypsum [Kacimi et.al .,2006], barium containing by-product [Rajczyk and Nocun, 1992], barite and fluorspar [Mullick et al., 1997]. [Helmy, 2003] reported the beneficial effect of adding as high as 15% phosphogypsum, granulated pig iron slag and cement kiln dust to the cement raw mix. The iron slag was found to be the most suitable mineralizer. The present study highlights the use of jarosite, which contains oxides of iron, sulphur, alkalis and zinc as mineralizer in the manufacture of ordinary Portland cement. 2.0 Experimentation Chemical analysis of jarosite and other raw materials such as limestone, iron ore, bauxite, gypsum and coal used in the study was carried out according to the procedures described in Indian standard IS:4032. Heavy and toxic elements present in jarosite was determined by Inductive Coupled Plasma-Optical Emission Spectrophotometer {ICP-OES) [Modei:VISTA– MPX, Varian Make]. The leaching study of heavy elements present in jarosite was carried out as per the procedure described in ASTM-D-5233 (1992), an agitated extraction test method and very similar to Toxicity Characteristics Leaching Procedure (TCLP). The mineralogy of samples was studied by X-ray diffraction (XRD) [Rigaku International, Japan, 0-MAX 2200V/PC] using CuKa radiation (A=1.5405A). To investigate the role of jarosite addition on the burnability of cement raw mixes, different raw II