METHOD OF PREPARING COAL FOR FUEL SUSPENSION Russian patent published in 1997 - IPC

FIELD: solid fuels; enrichment of coals. SUBSTANCE: to achieve low ash level in coal concentrate (not more than 5%) with no reduction in its yield, original coal is gradually disintegrated to particle size 11.0 mm, sludge is sorted in hydrocyclone to produce sands and drain. Sands are concentrated on table, heavy fraction is removed as reject, and light-weight one is additionally crushed to 0.1 mm and subjected to floatation. Hydrocyclonation drain is electrochemically treated with electrolysis products of liquid phase of suspension for 5-25 min and floated to produce waste tails and foam product which is refloated together with additionally crushed light-weight fraction of sands. Floatation is carried out in column-type pneumopulse floatation machine with pulse frequency 30-120 min^-1 and amplitude 3-15 cm. Invention may be used in integrated process of preparing low-ash water-coal suspensions. EFFECT: enhanced efficiency of process. 4 cl, 1 dwg