GB429998A - Improvements in or relating to the treatment of mineral sand for the separation of one constituent from another - Google Patents

Abstract

To separate the constituents of a mineral sand the sand is (a) washed with acid and then with water, (b) washed with a dilute soap solution or an emulsion of a fatty acid, and (c) agitated in water to give a floating concentrate which is removed. The sand is generally washed with water after the treatment with soap or fatty acid and before the agitation in order to remove any excess of the reagent. In a modification of the process the step (b) is performed before the step (a). When treating a sand containing zircon, rutile and monazite and using soap solution, if the acid used for washing is dilute, e.g. 1-10 per cent hydrochloric, the concentrate contains zircon and monazite, whereas if more concentrated acid, e.g. 10-20 per cent, is used the zircon alone floats, the monazite remaining in the sink portion with rutile and other constituents of the sand. The zircon-monazite float obtained when dilute acid is used may be washed with 10-20 per cent acid, washed with water, and again agitated with water to produce a zircon floating concentrate and monazite tailings. Sands free from zircon and monazite, e.g. tailings from a previous separation, may be treated by washing with acid and then with water, and then by agitating the treated sand with an emulsion of fatty acid, e.g. oleic acid, the rutile is obtained as a floating concentrate. Alternatively the tailings from a zircon-monazite separation may be agitated directly with fatty acid emulsion to recover the rutile. The water used is preferably free from calcium and magnesium salts and salts of the heavy metals; preferably distilled water or rain water is employed. The washing with acid, soap, water, &c. may be effected by placing the sand on a porous earthenware or fibre filter and allowing the acid &c. to percolate through the sand by gravity or by means of a suction pump. The agitation is preferably gentle and may be carried out in a machine having a slowly rotating paddle which projects the sand upwards towards the surface of the water, a small amount of air being admitted below the paddle to prevent silting. Specification 406,018 is referred to.