GB853017A - Separation of solids - Google Patents

Abstract

853,017. Washing granular materials. MINERAL PROCESSING CORPORATION. Oct. 14, 1958 [Oct. 22, 1957], No. 32795/38. Class 82(2) In a sink and float process for separating a mixture of solids of a wide particle size range of “ in. to 6 in. a heavy medium of intermediate specific gravity is contained in a separating cone 10, the solids and some medium are fed on to the surface of the bath via 11 and 25, the floats discharging at 13 over weir 12 and the sinks are removed via a U discharge conduit 16 at a point 18 positioned below the level of the medium in the cone, and a further quantity of medium is introduced into the cone at 28 so as to maintain a uniform specific gravity in the bath and to transport the sinks into a receptacle 15 in the form of a frustrum of a circular cone where sufficient medium or fluid is injected at 30 to maintain the largest sink particles in suspension while the stream is transported hydraulically through the conduit 16 to the discharge point 18. The difference in elevation between discharge point 18 and the surface of the medium in the cone governs the flow rate in conduit 16 and the height of 18 is determined by the largest size of the sink particles. The diameter of the apex opening 14 must be at least three times the diameter of the largest particles. and the lower opening of receptacle 15 must be at least twice the diameter of the largest particle, while the length of 15 should be at least six times the diameter of the largest particle. The heavy medium is a finely divided suspension of magnetite or ferrosilicon, an aqueous salt solution of zinc chloride or calcium chloride or a heavy organic liquid should as tetrabromethane C 2 H 2 Br 4 or bromoform CHBr 3 . The process is exemplified by the separation of anthracite coal from refuse.