Fundamental electrochemical and Raman spectroscopic investigations of the flotation behaviour of PtAs2

Platinum arsenide minerals are important platinum carriers in altered platinum reserves such as the Great Dyke of Zimbabwe and the Platreef (in the Bushveld Complex of South Africa). Industrial mineralogical investigations suggest these minerals to be poorly recovered during froth flotation and are believed to be slow floating. In this work, electrochemical investigations, electrochemical contact angle measurements and Raman spectroscopy have been employed to investigate the interaction of ethyl xanthate with synthetic PtAs2. The electrochemical investigations suggest a strong interaction of the xanthate with the mineral at potentials higher than the reversible potential of the xanthate–dixanthogen couple. Raman spectroscopy has confirmed the presence of dixanthogen on the mineral surface when the surfaces are anodically polarized. Contact angle investigations indicated the surface to be hydrophobic; possible mechanisms of the slow floating behaviour are discussed.