Study of Adsorption of Sodium Isopropyl Xanthate on Galena

Abstract

This paper deals with a study of the oxidation processes of the PbS-sodium isopropyl xanthate system in alkaline conditions (pH 8, similar to flotation circuits Pb-Cu) by using cyclic voltammetry and Electrochemical Impedance Spectroscopy (EIS). Three oxidation peaks are identified in the voltammograms that correspond to reactions previously reported in the literature. A plot of the differential capacitance of the double layer vs. potential gives a potential of zero charge (PZC) of -0.31 V vs. SCE for the system, that coincides with an oxidation peak attributed to the adsorption of xanthate. EIS at PZC for different xanthate concentrations evidence an adsorption processes via a charge transfer mechanism under diffusional control. EIS data at potentials more positive than PZC display an inductive loop that is related to a charge transfer processes involving the reaction of the adsorbed intermediates with the consequent modification of the PbS-sodium isopropyl xanthate interface.