Leaching Characteristics of Selected Elements from Indian Coal Ash
Long-term leaching experiments have been conducted to determine release of different ions and heavy metals from different coal ashes obtained from Ramagundam Super Thermal Power Plant, Andhra Pradesh and Chandrapura Thermal Power Plant, Jharkhand. Four columns of Ramagundam fly ash, bottom ash, pond ash, and weathered ash and three columns of Chandrapura bottom ash, pond ash, and weathered ash have been prepared. Leaching experiment has been conducted for one year. The leachates obtained have been monitored for levels of dissolved constituents and heavy metals. Results for leachates indicate that initially maximum concentrations of dissolved inorganic constituents, who have been admixed, with the surface of fly ash particles have been leached out. Irregular pattern of heavy metals released have been obtained in leachates. The leaching behaviour indicated slow and long-term leaching of heavy metals, which have been associated with the ash particles.
Cox, J.A., Lundquist, G.L., Przyjazny, A. and C.D. Schmulbach (1978). Leaching of boron from coal ash. Environmental Science and Technology, 12: 722-723.
Fleming, L.N., Abinteh, H.N. and H.I. Inyang (1996). Leachant pH effects on the leachability of metals from fly ash. Journal of Soil Contamination, 5(1): 53-59.
Gregory, R.M. and F. Roy (1985). Trace elements concentration as a function of particle size in fly ash from a pulverized coal utility boiler. Envi. Science. Technology, 19(9): 796-803.
Liem, H., Sandstrom, M., Wallin, T., Carne, A., Rydevik, U., Thurenius, B. and P. Moberg (1983). Studies on the Leaching and Weathering Processes of Coal ashes. Water Science Technology, 15: 163-191.
Prasad, B., Benerjee, N.N. and B.B. Dhar (1996). Environmental Assessment of Coal Ash Disposal: A review. Journal of Scientific & Industrial Research, 55: 772-780.
Prasad, B. and K.C. Jaiprakas (2000). Studies of Selected Coal Fly Ash leachates for Environmentally Safe Disposal. Indian J. Environ. Prot., 20(4): 275-279.
Prasad, B., Mondal, K.K. and A. Gupta (2004). Impact on water Environment due to Leaching of Heavy metals from Indian fly ash. Proceedings of International Seminar on Mineral Processing Technology 2004, Regional Research Laboratory, Bhubaneswar.
Querol, X., Umana, J.C., Alastuey, A., Ayora, C., Lopez- Soler, A. and F. Plana (2001). Extraction of soluble major and trace elements from fly ash in open and closed leaching systems. Fuel, 80: 801-813.
Theis, T.L. and K.H. Gardner (1990). Environmental Assessment of Ash Disposal. Critical Reviews in Environmental Control, 20(1): 21-42.
Vander Hoek, E.E., Van Elteren, J.T. and R.N.J. Comans (1996). Determination of As, Sb and Se Speciation in fly ash leachates. International Journal of Environmental Analytical Chemistry, 63: 67-79.
Vander Hoek, E.E. and R.N.J. Comans (1994). Speciation of As and Se during leaching of fly ash. In: Gaumans, J.J.J.M., Vander Sloot, H.A. and Aalbers, ThG. (Eds). Environmental aspects of Construction with Waste Materials. Elsevier Science, New York.
Wadge, A. and M. Hutton (1987). The Leachability and Chemical Speciation of Selected Trace elements in fly ash from Coal combustion and Refuse Incineration. Environmental Pollution, 48: 85-99.
Wasay, S.A. (1992). Leaching behavior of trace toxic metals from fly ash, their seepage control to ground water and utilization of fly ash. Journal of Environmental Science and Health, A27(1): 25-39.