| 摘要 |
A process for enhancing coal by removing the gangue (rock, shale, iron pyrites and the like) associated with the mined coal as it comes from the crushers before further treatment. The process described slurries the crushed run of the mine (ROM) coal with a heavy medium, such as perchloroethylene, for a short period of time at ambient or below temperatures, (i.e. slurry times of 5-30 minutes and temperatures of 90 DEG C. to below -10 DEG C.); thereafter allowing, in a substantially quiescent environment, the solids to settle or float as their inherent densities are greater or lesser respectively than the density of the heavy medium. After settling the float solids (mostly coal of lower sulfur and ash content) are separated from the heavy medium as one stream and the sink solids (mostly the gangue) as a second stream. These solids are each washed with hot (90 DEG C.-100 DEG C.) water and the vapor azeotrope which forms from the water and heavy medium mixture (azeotrope) removed. The now water wet solids are separated from the body of hot water and sent for further processing or loading. The solids, both the coal and the gangue, have a heavy medium content of less than about 400 parts heavy medium per million parts solids.
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