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US 4,290,897 AGranted
Dewatering fine coal slurries using two types of organopolysiloxanes
AssigneeDow Corning Corporation
InventorTerence J. Swihart
Life of this patent
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Abstract
Aqueous slurries of fine coal are dewatered by a process which comprises mixing a mixture of a water-soluble organopolysiloxane and a water-emulsifiable organopolysiloxane with the slurry, separating the slurry to recover the fine coal and further drying the fine coal, if desired. The use of a mixture of a water-soluble organopolysiloxane and a water-emulsifiable organopolysiloxane unexpectedly provides improved separating and/or improved drying of fine coal compared to a dewatering process that uses only one of the organopolysiloxanes.
Claims10
A process for dewatering an aqueous slurry of fine coal, said process comprising
- (I) mixing a dewatering-improving amount of a water-soluble organopolysiloxane plus a water-emulsifiable organopolysiloxane with the aqueous slurry of fine coal, said water-soluble organopolysiloxane and said water-emulsifiable organopolysiloxane having the formula R.sub.a H.sub.b SiO.sub.(4-a-b)/2 wherein a and b are numbers, the sum of which has an average value of from greater than zero to less than four, b has an average value of from zero to a and R denotes an organic radical bonded to a silicon atom by a silicon-carbon bond, the weight ratio of the water-soluble organopolysiloxane to the water-emulsifiable organopolysiloxane having a value of from 1/99 to 99/1,
- (II) separating the organopolysiloxanes-containing aqueous slurry of fine coal into an aqueous portion and a fine coal portion, said fine coal portion having a water content of less than 20 percent by weight.
Dependencies are inferred from the claim text.