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Title: Moist caustic leaching of coal

A process for reducing the sulfur and ash content of coal. Particulate coal is introduced into a closed heated reaction chamber having an inert atmosphere to which is added 50 mole percent NaOH and 50 mole percent KOH moist caustic having a water content in the range of from about 15% by weight to about 35% by weight and in a caustic to coal weight ratio of about 5 to 1. The coal and moist caustic are kept at a temperature of about C. Then, water is added to the coal and caustic mixture to form an aqueous slurry, which is washed with water to remove caustic from the coal and to produce an aqueous caustic solution. Water is evaporated from the aqueous caustic solution until the water is in the range of from about 15% by weight to about 35% by weight and is reintroduced to the closed reaction chamber. Sufficient acid is added to the washed coal slurry to neutralize any remaining caustic present on the coal, which is thereafter dried to produce desulfurized coal having not less than about 90% by weight of the sulfur present in the coal feed removed and having an ash contentmore » of less than about 2% by weight.« less
  1. (Elizabeth, PA)
Issue Date:
OSTI Identifier:
United States of America as represented by United States (Washington, DC) OSTI
Patent Number(s):
US 5312462
Research Org:
Pittsburgh Energy Technology Center
Country of Publication:
United States
moist; caustic; leaching; coal; process; reducing; sulfur; ash; content; particulate; introduced; closed; heated; reaction; chamber; inert; atmosphere; added; 50; mole; percent; naoh; koh; water; range; 15; weight; 35; ratio; kept; temperature; 300; degree; mixture; form; aqueous; slurry; washed; remove; produce; solution; evaporated; reintroduced; sufficient; acid; neutralize; remaining; thereafter; dried; desulfurized; 90; feed; removed; caustic solution; coal feed; reaction chamber; mole percent; inert atmosphere; coal slurry; aqueous slurry; particulate coal; weight ratio; water content; ash content; heated reaction; aqueous caustic; percent na; caustic leaching; closed reaction; closed heat; /44/