IRON HYDROXIDE COMPLEXES AND THEIR INFLUENCE ON THE INTERACTION BETWEEN ETHYL XANTHATE AND PYRITE

The zeta potential vs pH relationship of pyrite in the presence and absence of xanthate has been analyzed in terms of a model which assumes that dissolution of iron from the pyrite surface occurs, followed by the adsorption of iron hydroxide species and iron hydroxide-xanthate complexes onto this surface. The Gouy-Chapman-Stern model has been used to calculate the resultant zeta potential. The results have been correlated with both published flotation recovery data for pyrite and thermodynamic data for the formation of iron-xanthate complexes. In addition to dixanthogen, iron hydroxide-xanthate complexes are found to contribute to the flotation of pyrite. This analysis leads to a self-consistent interpretation of all of these observations if ferric and ferrous hydroxide-xanthate species are assumed to be present on the pyrite surface. © 1992.