Geochemistry of Coal Ash in the Equatorial Wet Disposal System Environment
Kolay P. K.;
The coal utilization in thermal power plants in Malaysia has increased significantly which produces an enormous amount of coal combustion by-product (CCBP) or coal ash and poses severe disposal problem. As each coal ash is distinct, this study presents the geochemistry of the coal ash, in particular fly ash, produced from the combustion of local coal from Kuching Sarawak, Malaysia. The geochemical composition of the ash showed a high amount of silica, alumina, iron oxides and alkalies which was found to be a convenient starting material for the hydrothermal synthesis of zeolites with the higher Na2O percentage being a positive factor for its alkaline activation; while the mineral phases are mainly quartz, mullite, calcium oxide, silica, and iron oxide hydrate. The geochemical changes upon alkali activation that can be predicted in a similar type of ash have been described in this paper. The result shows that this particular ash has a good potential for a high value industrial product like zeolites upon alkali activation.
Amrhein, C., Haghnia, G.H., Kim, T.S., Mosher, P.A., Gagajena, R.C., Amanios, T., & De La Torre, L. Synthesis and properties of zeolites from coal fly ash, Environ SciTechnol, Vol. 30, pp. 735-42, 1996.
Janssen-Jurkovocova, M., Hollman, G. G., Nass, M. M., &Schuiling, R. D. Quality assessment of granular combustion residue by a standard column test: prediction verses reality, KEMA Report No. 74947-KES/BCO, 1994.
Kolay, P. K., & Singh, D. N. Effect of zeolitization on physical-chemical-mineralogical and geotechnical properties of the lagoon ash, Canadian Geotechnical Journal, Vol. 38, No. 5, pp. 1105-1112, 2001.
Lister, R. A., & Peterson, T. J. Recent developments in dry ash handling, V. S. Raju., M. Datta, V. Seshadri, V. K. Agarwal and V. Kumar, (Eds.), Ash Pond and Ash Disposal Systems, Narosa Publishing House, India, pp. 86-96, 1996.
Mohd Annas B. Mohd. Nor, Future coal utilization in Malaysia, 2005 APEC Clean Fossil Energy Technical and Policy Seminar, 2005, 26-29th January, Cebu City Marriott Hotel, The Philippines.
Sharma, R. S. Geo-environmental aspects of fly ash utilization and disposal, In: Raju, V. S., Datta, M., Seshadri, V., Agarwal, V. K.& Kumar, V. (Eds.): Ash Pond and Ash Disposal Systems, Narosa Publishing House, India, pp. 347-357, 1996.
Shih, W.H., Chang, H.L., &Shen, Z. Conversion of fly ash to zeolites, In: Advances in porous Materials Research Society Symposium proceedings, Vol. 371, Material Research Society, Pittsburgh, PA, USA, pp. 39-44, 1995.
 Wang, S. B., Soudi, M., Li, L. and Zhu, Z. H. Coal ash conversion into effective adsorbents for removal of heavy metals and dyes from wastewater, Journal of Hazardous Materials, Vol. 133, No. 1-3, pp. 243-251, 2006.
 Querol, X. N., Moreno, A. Alastuey, R. Juan, J.M. Andrés A. López-Soler C. Ayora, A. Medinaceli and A. Valero. Synthesis of high ion exchange zeolites from coal fly ash, Geologica Acta, Vol. 5, No. 1, pp. 49-57, 2007.
 Komarneni, S. Heavy metal removal from aqueous solutions by tobermites and zeolites, NuclChem Waste, Vol. 5, pp. 247-50, 1985.
 Hollman, G.G., Steenbruggen, G., & Janssen-Jurkovicova, M. A two step process for synthesis of zeolites from powder coal fly ash In: International Ash Utilization Symposium, Kentucky, U.S.A., 20-22 October, 1997.
 Breck, D.W. In: Townsend, R.P. (Ed.): Properties and application of zeolites, The Chemical Society, London, 1979.
 Chang, H.I., & Shih, W.H. General method for conversion of fly ash into zeolites as ion exchanges for cesium, IndChem Res, Vol. 37, No. 1, pp. 71-8, 1998.
 Ma, W., Brown, W., & Komarneni, S. Characterisation and cation exchange properties of zeolite synthesized from fly ashes, J. Mater Resources, Vol. 13, No. 1, pp. 3-7, 1998.
 ASTM D 854-92. Standard Test Method for Specific Gravity of Soil, Annual Book of ASTM Standards, 04.08, Philadelphia, USA, pp. 80-83, 1994.
 ASTM C 618-94. Specification for coal fly ash and raw or calcined natural pozzolanic for use as a mineral admixture in Portland cement concrete, Annual Book of ASTM Standards, 04.02, Philadelphia, USA, pp. 296-298, 1994.
 Valkovic, V. Trace Elements in Coal, CRC Press, Boca Raton, USA, 1983.
 Kolay, P.K., Singh, D.N., &Murti, M.V.R. Synthesis of zeolites from a lagoon ash, Fuel, Vol. 80, pp. 739-745, 2001.
 Singer, A., & Berkgaut, V. Cation exchange properties of hydrothermally treated coal fly ash, Environ SciTechnol, Vol. 29 No. 7, pp. 1748-53, 1995.
 Kolay, P. K. Characterization, water-Interaction and zeolitization of a lagoon ash, Ph. D Thesis, Department of Civil Engineering, IIT Bombay, India, 2001.
 Vucinic, D., Miljanovic, I., Rosic, A., &Lazic, P. Effect of Na2/SiO2 mole ratio on the crystal type of zeolite synthesized from coal fly ash, J. Seb. Chem. Soc., Vol. 68, No. 6, pp. 471-478, 2003.
 Breck, D.W. Zeolites Molecular Sieves, Wiley, New York, 1971.
Thaddeus, J. Complementary roles of natural gas and coal in Malaysia-case study. The Joint 8th APEC Coal Flow Seminar and 9th Clean Fossil Energy Technical Seminar, 2002, 4-5 March, Kuala Lumpur, Malaysia.
Theis, T.L., & Gardner, K.H. Environmental assessment of ash disposal, Critical Reviews in Environmental Control, Vol. 20, No. 1, pp. 21-42, 1990.