| 摘要 |
Both water and carbonaceous material are reclaimed from an aqueous slurry of particles of coal that contains both carbonaceous and non-carbonaceous materials, the slurry being comprised of at least 60 percent water by weight. Preferably, the geometric mean particle size of the coal particles in the aqueous slurry is less than 150 microns. Preferably, the processed aqueous slurry is formed by mixing a low solids aqueous slurry of coal and ash fines from a coal washer with a high solids aqueous slurry of coal and ash fines from a settling pond. A fluid that is in a free-flowing liquid state at temperatures below 80 DEG C. and, preferably, at temperatures below 20 DEG C., and that is lyophobic to the water and the non-carbonaceous particles of the coal, and lyophillic to the carbonaceous fine particles of the coal is added to the aqueous slurry to form a first mixture in which less than 20 percent by weight of the fluid and the carbonaceous and non-carbonaceous coal particles is fluid. The first mixture is then agitated to preferentially agglomerate the carbonaceous particles to form carbonaceous agglomerates while the non-carbonaceous particles remain substantially dispersed in the slurry. The carbonaceous agglomerates are separated from the mixture to form a substantially non-carbonaceous aqueous slurry. A preferably high molecular weight flocculant that is lyophobic to water and lyophilic to non-carbonaceous material is thereafter added to the non-carbonaceous aqueous slurry to form a second mixture, and flocculated solids precipitated from the second mixture to form water and precipitate from the second mixture. Flocculated solids are then separated from the precipitate to provide a substantially solids-free aqueous solution. Preferably, the water separated from the second mixture is recirculated to a coal washing plant, and the solids-free aqueous solution separated from the precipitate is recirculated to the second mixture, or a coal washing plant, to form a closed water system for a coal washing plant.
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