GB972428A - Apparatus for the treatment of mixtures of fine granular minerals by the flotation method - Google Patents

Abstract

972,428. Centrifugal separators; flotation apparatus. BETEILIGUNGSUND PATENTVERWALTUNGSGESELLSCHAFT m.b.H. July 26, 1963 [July 28, 1962], No. 29833/63. Headings B2H and B2P. An apparatus for concentrating fine granular mineral, e.g. coal, by froth flotation of an aerated pulp of the mineral containing one or more flotation agents includes a centrifugal separator 10, Fig. 1, comprising a partly conical vessel 15, Fig. 3, provided with a supply pipe 9 for the pulp leading tangentially in its upper part, a lower discharge outlet 16 for the residue and a central discharge outlet for the froth situated at the top and constructed in the form of an overflow, the lower tubular end 18 of which, with a diameter equal to at least 60% of that of the upper end of the vessel, is extended downwards only to about the centre line of the mouth of the supply pipe 9 and is provided with baffle plates 19 only in its interior. The upper end 20 of the froth discharge outlet is in the form of a funnel provided with baffle plates 21 horizontally and/or vertically arranged. The baffle plates consist of perforated plates or of lattice screens. The coal-containing froth may be skimmed off by known devices from the top of the funnel 20 or may overflow into a froth tank 22. In a modification, the funnel 20 is surrounded by a further funnel defining an intermediate conical annular space forming a settling zone for wrongly discharged residue-containing pulp which can be drawn off through bores in the lower end of the outer funnel. Raw coal is mixed with water and floatation agents in a mixing tank 1 and conveyed to a reservoir 7 by a rotary pump 4 or one or more air injectors, the injectors also providing aeration of the pulp. The pulp then flows towards the supply pipe 9 ahead of which are provided a screw 11, Fig. 3, for setting the pulp in rotation, and an air injector in the form of a nozzle 12 fed through a pipe 13 for aerating and whirling the pulp. The pipe 9 has a portion 14 of widened cross-section in which the pulp is relieved of pressure before entering the separator. A pipe line 25 may be connected to the outlet 16 of the separator to convey the residue to one or more centrifugal separators for further treatment.