An overview of the use of coal cleaning to reduce air toxics

Environmental Aspects of Trace Elements in Coal

“…From 0 to 94010 of the F was removed in commercial coal cleaning tests (Akers and Dospoy, 1992). The large reductions in F content were achieved on coals having more than 500 ppm F and the small reductions were obtained on coals having less than 50 ppm F. Wide ranges of F reduction were also reported by Ford and Price (1982), Junk et al (1986), and Cavallaro et al (1978.…”

“…The wide range of Cd removal during coal cleaning (Akers and Dospoy, 1992;Cavallaro et al, 1978;Ford and Price , 1982;Junk et al, 1986) is likely due to the different modes of occurrence of sphalerite (Finkelman, 1985). In some coals sphalerite occurs as large (> 100 j.tm) crystals filling cleats and fractures.…”

“…It is conceivable that the different behaviours of Pb in coal cleaning studies (Akers and Dospoy, 1992;Cavallaro et al, 1978;Junk et al, 1986;Ford and Price, 1982) is a reflection of the different ways in which the Pb-bearing minerals occur. Lead would be effectively removed if it occurred primarily in cleat-filling galena or in galena attached to massive pyrite.…”

Reduction of Inherent Mercury Emissions in Pc Combustion

“…Thus, physical coal cleaning is capable of significantly reducing the heavy metal content. Although some mercury is associated with pyrite, coal cleaning generally has not been as effective at removing mercury (Boren and Wan, 1990;Akers andDospay, 1993, 1994;Devito et al, 1994). For example, the results of Devito et al (1994) show only 30-40 percent removal during physical coal cleaning, as compared to 75-85 percent for the other trace elements and the minerals as a whole.…”