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APPLICATION OF OIL AGGLOMERATION FOR EFFLUENT CONTROL FROM COAL CLEANING PLANTS
Citation:
Mezey, E., T. Hayes, R. Mayer, AND D. Dunn. APPLICATION OF OIL AGGLOMERATION FOR EFFLUENT CONTROL FROM COAL CLEANING PLANTS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/7-85/042.
Description:
The report discusses the potential applicability of oil agglomeration for the control of black water effluents from coal cleaning plants processing four different coals. Removal and recovery of the coal from each of the black waters produced aqueous suspensions of mineral matter that settled more rapidly than the original black water. The sediment recovered from the agglomeration appears to be less prone to acid generation during aeration than the total black water sediment. The ash and sulfur content of the coal recovered by agglomeration is less than that of the cleaned coal. The quality of the recovered coal can be improved by chemical treatment of the sediment before agglomeration. Sodium sulfide appears to be one of the better agents to use because of the simplicity of the treatment process. Such pretreatment of the sediment can reduce the pyrites by up to 50% in the recovered coal over that without pretreatment. Even greater reductions in pyrite and ash are realized after pretreatment when the amount of oil used for agglomeration is reduced from 10 to about 2% and a two-stage air-float separation is used to recover the agglomerated coal. The cost of the oil-agglomeration recovery of fine coal from coal preparation effluent streams is about $18 to $22 per ton of coal recovered, assuming an oil price of $0.90 per gal.