97/04407 Fine coal circuitry using advanced physical cleaning processes: Honaker, R. Q. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1996, 13, (2), 1375–1380

Abstract

Recent investigations have found that enhanced gravity separators (EGS) and flotation columns are highly efficient for cleaning fine coal. The test results presented in this publication show that a circuit comprised of two advanced gravity separators, i.e., a hindered-bed classifier and an EGS, and a flotation column provides an enhanced cleaning efficiency for the treatment of {minus}16 mesh coal. From in-plant experiments, the hindered-bed classifier was found to be a more efficient separation device (E{sub p} = 0.12) than coal spirals (E{sub p} = 0.18) for the treatment of a nominally 16 x 100 mesh coal. Since its efficiency declines for particle sizes less than 48 mesh, the hindered-bed classifier overflow was screened to produce a final +48 mesh concentrate and a {minus}48 mesh fraction that was subsequently treated by circuits incorporating the EGS and flotation column in combination and separately. The best overall circuits in terms of both ash and total sulfur reductions for treating the -16 mesh coal was found to be the Hindered Bed-EGS-EGS and Hindered Bed-EGS-Column circuits. Both circuits rejected over 70% of the ash and over 60% of the pyritic sulfur while recovering over 85% of the combustible material.