An investigation into electrochemical interactions between platinum group minerals and xanthate: Voltammetric study

• Cyclic voltammetry measurements were made on Pt, Pd, PtS, PdS, PtTe2 and PdTe2.
• SEX adsorption on telluride minerals were found to be different from sulphide minerals.
• Oxidised collector species identified were of two types, viz. dixanthogen and the metal thiolate.

In the flotation of platinum group minerals (PGMs) containing significant amounts of tellurides and arsenides it is generally assumed that these minerals will respond in the same way as sulphides to collectors such as xanthates which are typically used in sulphide flotation. This paper presents the results of a fundamental study which has been conducted to provide a greater insight into the comparative interactions between synthetic moncheite (PtTe2) and cooperite (PtS) with sodium ethyl xanthate (SEX). Cyclic voltammetry has been used to investigate these interactions in the absence and presence of sodium ethyl xanthate (SEX) in aerated and de-aerated solutions. Reduction potentials of the SEX/dixanthogen couple have been measured and compared to published data. Reduction potentials of possible reactions of the minerals have been predicted from thermodynamic calculations and used to attempt to interpret the potentials measured in the cyclic voltammetry investigations. Results have shown differences in the oxidation behaviour of the minerals as well as in the SEX interaction with the minerals. The effect of pH was investigated in the case of the Pt minerals and fractional surface coverages were calculated with a view to ultimately correlate these results with flotation behaviour. Proposals are made with respect to the various reactions occurring under the conditions studied.

Figure optionsDownload as PowerPoint slide