Metal release from fly ash upon leaching with sulfuric acid or acid mine drainage
- West Virginia Univ., Morgantown, WV (United States)
Generation of electricity by coal-fired power plants produces large quantities of bottom ash and fly ash. New power plants commonly use fluidized bed combustion (FBC) boilers, which create ashes with high neutralization potential (NP). These ashes, due to their alkaline nature, are often used in surface mine reclamation to neutralize acidity and reduce hydraulic conductivity of disturbed overburdens. Conventional fly ashes from older power plants exhibit a range of pH and NP, with some ashes having neutral or acidic pH and low NP values, and may not be good candidates for supplying alkalinity in reclamation projects. In this study, the authors used two acidic solutions to leach a low NP fly ash (LNP ash) and two FBC ashes (FBC1 and FBC2). After passing 78 pore volumes of sulfuric acid and 129 pore volumes of acid mine drainage (AMD) through these ash materials several trace elements were found at high levels in the leachates. LNP fly ash leachates had high arsenic and selenium concentrations with sulfuric acid leaching, but showed low arsenic and selenium concentrations after leaching with AMD. Leaching with AMD caused the iron and aluminum inherent in AMD to complex these elements and make them unavailable for leaching. Lead, cadmium, and barium concentrations in fly ash leachates were not high enough to cause water pollution problems with either leaching solution. For both leaching solutions, manganese was released from LNP ash at a constant level, FBC1 ash did not release manganese, and FBC2 ash released manganese only after the NP had been exhausted by >60 pore volumes of leaching.
- OSTI ID:
- 361694
- Report Number(s):
- CONF-9805185-; TRN: IM9933%%75
- Resource Relation:
- Conference: 15. American Society for Surface Mining and Reclamation (ASSMR) annual national meeting, St. Louis, MO (United States), 17-21 May 1998; Other Information: PBD: [1998]; Related Information: Is Part Of Proceedings of the 15. annual national meeting of the American Society for Surface Mining and Reclamation. Mining -- Gateway to the future; Throgmorton, D.; Nawrot, J.; Mead, J.; Galetovic, J.; Joseph, W. [eds.]; PB: 801 p.
- Country of Publication:
- United States
- Language:
- English
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