An investigation into the electrochemical interactions between platinum group minerals and sodium ethyl xanthate and sodium diethyl dithiophosphate collectors: Mixed potential study

Abstract

In the flotation of platinum group minerals (PGMs) occurring in the Platreef ore body, it is often assumed that the interactions between thiol collectors and tellurides of Pt and Pd are similar to those occurring with the equivalent sulphides. In order to gain a greater insight into this assumption a rest(mixed) potential study was conducted to investigate the interactions occurring between two thiol collectors, viz. sodium ethyl xanthate (SEX) and sodium diethyl dithiophosphate (SEDTP), and selected PGMs, viz. moncheite (PtTe2), merenskyite (PdTe2), cooperite (PtS) and vysotskite (PdS) as well as pure platinum and palladium. The results have shown that all these minerals reacted with the collectors in question but that the rest potential of the Pt minerals are more anodic than those of the Pd minerals. Moreover when SEX was used, dixanthogen is more likely to form on PtS than PtTe2 but the reverse is the case for PdTe2 and PdS. In the case of SEDTP it was found that the dithiolate (SEDTP2) did not form on any of the mineral surfaces. The results were compared to those already reported in a previous investigation of the same systems using cyclic voltammetry. The information obtained in these two investigations complement each other and may provide a more fundamental understanding of the role of these collectors in recovering the respective minerals.