The flotation of auriferous pyrite with a mixture of collectors

Dithiocarbonates (xanthates) have been the most widely used collectors in sulphide mineral flotation. More recently, research has resulted in the use of trithiocarbonate (TTC) collectors. The present study focuses on the effect of mixtures of C12 trithiocarbonate (C12 TTC) and sodium iso-butyl xanthate (SIBX) in the flotation of auriferous pyrite and the associated gold and uranium from cyanidation tailings. Improved gold and uranium flotation responses were observed with collector mixtures than with SIBX alone. Sulphur recoveries were not affected. Mineralogical analysis of flotation concentrates showed that gold and uranium were also hosted by kerogen. It was therefore proposed that the improved recoveries could have been mostly due to higher kerogen recovery rather than synergism in pyrite flotation. This mechanism opens possibilities into maximising uranium recoveries in auriferous flotation circuits where low recoveries are common.