Electrochemical control of metallic copper and chalcopyrite-xanthate flotation

The surface oxidation of copper dipped in xanthate-free and xanthate-containing borate solutions of pH 9.2 was analysed by small amplitude cyclic voltammetry. The influence of the electrochemical potential on the floatability of copper and chalcopyrite particles was investigated. It was demonstrated that the formation of copper-xanthate species derives not only from the direct reaction between copper and xanthate ions but also from the one between xanthate ions and chalcopyrite. Evidence was found that the species responsible for the hydrophobization of copper and chalcopyrite particles are copper-xanthate species and dixanthogen. Flotation tests carried out in a microflotation-electrochemical cell and in an electrochemical Denver cell demonstrated that maximum floatability is obtained when both species are present on the surface. A potential decay measurement was conducted in order to analyse the stability of the species responsible for hydrophobization.