Distribution and material balances of trace elements during coal cleaning
- Consol Inc., Library, PA (United States). Research and Development
A material balance was performed around a coal preparation plant as part of a trace element assessment program being conducted by CONSOL Inc. (CONSOL). The purpose of this program is to follow the fate of selected elements during mining, cleaning, combustion and waste disposal. The material balance reported here was performed at a time when the plant was operating entirely on freshly mined (as opposed to stockpiled) coal . All major inlet and outlet streams were sampled and analyzed. Using the design plant flows, closures of balances of the major components (ash, carbon, hydrogen, nitrogen and sulfur) were between 81 and 107%. Balance closures for the major coal ash elements (Na, K, Mg, Ca, Fe, Ti, P, Si, and Al) ranged from 73 to 82% based on the design flows, while balance closures for the trace elements (As, Be, Cd, Cr, F, Hg, Mn, Ni, Pb, Sb and Se) averaged 89 {+-} 20%, excluding Be, which was below the detection limits in three of the five streams. Most of the balance closures were significantly improved by adjusting the flow rates based on a least-squares fit of the ash, carbon, total sulfur, pyritic sulfur, Fe{sub 2}O{sub 3}, Al{sub 2}O{sub 3} and SiO{sub 2} data. Based on the adjusted flow rates, the major component balance closures were between 94 and 100%, the major inorganic element balance closures were 90 to 100%, and the trace element balance closures, excluding Be, averaged 103 {+-} 23%. Most of the trace elements are associated with the mineral components and are removed from the raw coal in approximately the same proportion as the ash. The only trace elements that are present in the waste water at concentrations more than double those in the feed water are As, Pb, and Sb, and these are discharged at levels 5--20 times lower than those allowed by Federal primary drinking water standards.
- OSTI ID:
- 143764
- Report Number(s):
- CONF-9305264-; TRN: IM9413%%274
- Resource Relation:
- Conference: COAL PREP `93: 10th international coal preparation exhibition and conference, Lexington, KY (United States), 4-6 May 1993; Other Information: PBD: 1993; Related Information: Is Part Of Coal prep `93: 10th international coal preparation exhibition and conference; PB: 298 p.
- Country of Publication:
- United States
- Language:
- English
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