Process for concentrating mica in a mixture of sand and mica

Abstract

A process for concentrating mica in a mixture of sand and mica is disclosed, which comprises introducing the feed mixture of sand and mica into an upper part of a density separating vessel in which is provided a rising current of an aqueous medium, the velocity of the current being uniform or substantially uniform over a horizontal cross-section of the vessel and being such that all but the least buoyant particles of the mixture are held in suspension as a bed which is gently displaced upwards in the vessel by incoming feed mixture; and passing a slurry which overflows from the vessel over a screen having an aperture size in the range from 210 .mu.m to 500 .mu.m (No. 72 mesh to No. 30 mesh B.S sieve), there being retained on the screen a mixture of sand and mica having a higher percentage content of mica, as calculated in the dry state, than the feed mixture. The mica can be concentrated sufficiently to provide a suitable feed for a subsequent froth flotation process which conventionally requires a mica content of at least 25% by weight.

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