GB562215A - Improvements in or relating to the washing of coal - Google Patents

Abstract

562,215. Wet separating. BERK & CO., Ltd., F. W., and SLACKE, R. L. R. Dec. 21, 1942, No. 18120. [Class 82 (ii)] In the washing of coal slurries from coal washers in which the slurry is treated by a sink-and-float process using as the heavy liquid a suspension in water of the shale present in the coal, two vessels containing water are connected by a syphon, the water in the first vessel being maintained at a substantially constant level and above the level of the water in the second vessel, the leg of the syphon dipping into the first vessel having a constriction above which coal slurry containing shale particles are supplied to that leg at a substantially constant pressure, so that a teetering suspension containing coal and shale particles is maintained above the constriction from which the coal particles are preferentially removed by the syphon. The syphon pipe 11 connects the second vessel 12 with a washer 7 having a constriction in the form of a spigot 8, above which is a sorting column 9, the latter and the washer 7 forming one leg of the syphon which dips into the first vessel 21. The discharge of the vessel 12 passes into a funnel 13 and a pipe 14 and the washer 7 is provided with a jigging diaphragm 15, and evacuating pipe 17 and a filling pipe 18 controlled by a pipe 19. The vessel 21 is connected to a dust elevator casing 22 for removing the shale and has water standing at a substantially constant level. A constant feed tank 1, fed by a valvecontrolled pipe 2, is provided with an overflow pipe 4, a slurry pipe 5 and connected by a feed pipe 6, itself connected tangentially to a water chamber 10 in the washer 7. In operation, the valve 20 is closed and the pipe 6 plugged. The washer is filled with water through the pipe 18 and as soon as water overflows through the pipe 11, the plug is removed from the pipe 6 and the valve 19 closed. When the vacuum indicated by the gauge 16 corresponds to the total height of the water above the level in the vessel 21, the valve 20 is opened fully. The slurry supply in the pipe 5 is now turned on which stops the supply through the pipe 2 and any excess overflows through the pipe 4 so that slurry is supplied at substantially constant pressure. A preliminary sorting of the coal and coarser shale is effected in the vicinity of the chamber 10, the coarse shale gravitating directly to the column 9 and the fine shale is prevented from rising and remains to form the heavy suspension. The coal is preferentially removed by the syphon pipe 11, a pipe 17 evacuating the large quantity of air contained in the slurry.