GB1145157A - An improved process for the separation of a mixture of substances having different specific gravities - Google Patents

Abstract

1,145,157. Wet separation of granular materials. R. O. STOKES & CO. Ltd. 21 March, 1967 [29 March, 1966], No. 13777/66. Heading B2H. In a plant for separating for example, coal from shale, a mixture of the latter and water is fed from a distributing box 1 on to a screen 3 for separation of the fines which are fed with the water by a pump 35 through a cyclone 37 from which the water and slime pass into an effluent pond. 39 and the dewatered fines pass into a hydraulic classifier 43 in which the teetering medium: is water. The fine shale settles down and is discharged at 48 into a sump 49 from which it is pumped to a dewatering cyclone 39. The rejected slime and water is then pumped to the pond 39 and the dewatered shale drops on to a waste shale conveyor 19. The fine coal is floated off the classifier at 45 and passes into a sump 27. The oversize coal and shale mixture from the screen 3 is fed to another hydraulic classifier 7 in which the teetering medium is a mixture of sand, introduced from a thickening cyclone 9, and water. The coarse shale together with a certain amount of sand passes out from the bottom of the classifier on to a screen 13 from which the oversize shale is discharged on to the conveyor 19 while the undersize sand is led to a sump 31. The coarse coal with some sand is floated off at 21 and led to a screen 23 from which the coarse coal is discharged to join the fine coal at 25 in its passage to the sump 27 while the undersize sand is led to the sump 31. The mixture of fine and coarse coal is pumped from the sump 27 through a centrifuge or other dewaterer before use. The sand in sump 31, which may also contain fresh sand from a hopper 17, is pumped to the cyclone 9. Water is pumped to the bottom of each hydraulic classifier from a supply 55. The plant may also be used to separate coke and clinker or a mixture of metalliferous ores. The teetering medium in the latter case being a mixture of barytes and water.