GB500043A - Improvements in or relating to the method of and apparatus for separating materials - Google Patents

Abstract

500,043. Wet-sepaxating. JACKSON, L. MELLERSH-.(Jeffrey Manufacturing Co.) July 27, 1937, No. 20785. [Class 82 (ii)] Materials of different specific gravities, e.g. coal and shale, are separated by the float and sink process in an aqueous suspension of argillaceous material such as clay, silt, shale, &c., with or without a granular material such as sand or crushed ganister, the constituents being maintained in suspension by the addition of a deflocculating agent such as sodium silicate or aluminate, as described in Specification 500,190. The medium is mixed and allowed to age, preferably for about 24 hours, before being introduced into the separating tank ; the float and sink are removed by conveyer, and the float is subjected to a plurality of successive washing operations to remove any adhering separating medium The dry coal may be introduced directly into the separating tank 12 through a hopper 16 with slidable gate 17, as shown in Fig. 1, or it may be first introduced into a water bath 95 as shown in Fig. 3. The separating tank has two discharge conveyers 18 and 23, which may be either as shown in Fig. I or as in Fig. 3, and the floating coal removed by the conveyer 23 is passed through a series of tanks 13, 14, 15 containing water, by means of scraper conveyers 27, 32, 33. The heights of the partitions between the washing tanks are such that water introduced into the tank 15 overflows into tank 14 and then to tank 13. The tanks are provided with discharges 43, 44, 45, and in operation only the discharge 43 of tank 13 is normally open. The sludge withdrawn from the washing tanks and any sludge from the preliminary wetting tank 95 is passed to one of two settling tanks 60, 61, Fig. 8, one tank being filled while settling is taking place in the other. Clean water is withdrawn from the latter and supplied to the end washing tank 15, the supply being preferably controlled by a pivoted float 81 in the tank 15 which on falling a certain distance operates a switch 83 to close an electric circuit containing a solenoid 86 which when energized closes a circuit containing a motor 65 working a pump 64 in the supply line between the settling tanks and the tank 15. The settled clay or clay and sand in the settling tank in which settling has taken place is withdrawn by a scraper conveyer and passed to one of two mixing, ageing, and storage tanks 73, 74, the tanks being supplied alternately one from the settling tank 60 and the other from the tank 61. One tank is used for mixing and ageing while the other, in which mixing and ageing has already taken place, is used to supply the separating tank 12, the supply being preferably controlled by a float in the tank 12. Instead of the two tanks 73, 74 supplied alternately, the medium may be mixed and allowed to age in one or more tanks and then passed to a storage tank used for supplying the separating tank.