Flotation of Galena and Chalcocite of Near-colloidal Size with Potassium Amyl Xanthate and Amyl Dixanthogen

Abstract

In the beneficiation of ores by ore-dressing processes the treatment of the finest portion of an ore has always been a problem difficult, if not sometimes impossible, of solution. Flotation has proved no exception to this rule. In the "near-colloidal" size-range of mineral particles embracing the entire scale from 5 microns to the size of the truly colloidal particles recovery by flotation has been found to be very unsatisfactory (1, 5).A study directed to improve the flotation behavior of these particles has been carried on at the Montana School of Mines since 1931. It resulted in the discovery of a successful experimental solution of the problem of flotation of near-colloidal pulps (6). By adding the collector into the pebble mill, so that it is present while the minerals are being ground, satisfactory flotation results can be obtained. This holds true for a number of collectors that comprise a group of the most common ones and of some of their less common derivatives (6).The present paper deals with the investigation of the effect of some arbitrary variables on the flotation behavior of two mineral mixtures (galenaaplite and chalcocite-aplite) when the collector is present during the grinding.The variables investigated are: (a) the effect of increasing amount of collector; (b) the effect of some alkaline pH-modifying agents; and (c) the effect of substituting a "neutral" grinding atmosphere for g,ir atmosphere. The study of the effect of the three variables was confined to two collectors: potassium «-amyl xanthate and its oxidation derivative, «amyl dixanthogen («-amyl thioformate disulfide).