Long term leaching studies on Coal Combustion Residues from Balco Captive Power Plant, Korba

Centre of Mining Environment, Indian School of Mines, Dhanbad-826 004, Jharkhand, India E-mail : sumit_ism@yahoo.com Department of Applied Chemistry, Birla Institute of Technology, Mesra, Ranchi-835 215, Jharkhand, India Manuscript received 8 August 2007, revised 7 January 2008, accepted 10 January 2008 The study was conducted to assess the leaching of coal combustion residues (CCRs) from Balco Captive Power Plant, Korba, India through five different standard techniques. The leaching procedures included acid digestion, short term (24-hour shake test, TCLP) and long term leaching (Open column percolation experiments, ASTM column experiments) studies for a period of more than three years. The physico-chemical characteristics (pH, conductivity and TDS) were observed within the permissible limits. The leachates were analysed for twenty-three elements like Na, K, Mg, Ca, Fe, Ni, Cu, Zn, Pb, Mn, Cr, Co, Cd, Se, AI, Ag, As, B, Ba, V, Sb, Mo, W and compared with their compositional analysis. Among these elements, only Na, K, Mg and Ca were found to be leaching throughout the study period and were within permissible limits of the prescribed standards (IS : 2490). However, Fe, Pb, Ni, Cu and Mn were observed at significant concentration levels on a few occasions. Overall, this study establishes the CCRs of Balco Captive Power Plant as environmentally benign material and encourages its large-scale utilisation