JPS6433189A - Method for coarse grain separation from high concentration coal-water slurry - Google Patents

Abstract

PURPOSE:To increase product yield and improve product quality in a coarse grain separation using a screen, by adding a dehydration inhibitor to a high- concn. coal-water slurry prior to the coarse grain separation. CONSTITUTION:A high-concn. coal-water slurry is produced by feeding in appropriate amts. a charge coal from a hopper 1, water from a first tank 2 and a dispersant from a second tank 3 into a wet mill 4, and operating the mill. Added to the high-concn. coal-water slurry (coal concn. : about 60-75%) obtd. in the wet mill 4 is a dehydration inhibitor from a third tank 5 in an appropriate amt. From the high-concn. coal-water slurry, coarse coal grains are separated using a screen 6. A high-quality product which has passed through the screen 6 is collected in a storage tank 7, and the separated coarse coal grains are returned to the wet mill 4 for re-pulverization. At this time, the trouble that fine coal grains do not pass the screen 6 due to the dehydration of the high- concn. coal-water slurry on the screen 6 can be avoided by the action of the dehydration inhibitor. Thus, product yield can be sufficiently enhanced.