The Auxiliary Effect of Copper Ions on the Depressant Effect of Sodium Thioglycolate in Chalcopyrite Flotation

Abstract

Sodium thioglycolate is a chalcopyrite depressant, but its depressant effect is weak. The paper investigated the effect of CuSO4 on the depressant performance of sodium thioglycolate towards chalcopyrite through flotation tests, Zeta potential measurements, X-ray photoelectron spectroscopy (XPS) analyses and Fourier-transform infrared (FTIR) spectra measurements. It was found that copper ions could improve the depressant effect of sodium thioglycolate on chalcopyrite. The results showed that copper ions could adsorb on the surface of chalcopyrite and form mixed copper sulfide and cupric oxides/hydroxides adsorption layers. As a result, the mineral composition on the chalcopyrite surface was changed. With sodium thioglycolate treatment, the Zeta potential and the adsorption sites of chalcopyrite surface were both increased, and the hydrophobic substance Sn2−/S0 concentration was decreased. The electrostatic repulsion of chalcopyrite surface with sodium thioglycolate was also decreased, which made the sodium thioglycolate interact with chalcopyrite more easily. The more active sites could adsorb more sodium thioglycolate, which improved the hydrophilia of chalcopyrite. At the same time, the decrease of Sn2−/S0 concentration could further improve the hydrophilia of chalcopyrite. The results show that the copper ions could exhibit auxiliary effect with sodium thioglycolate and could further enhance the depressant effect of sodium thioglycolate on the chalcopyrite flotation. This paper provides new insights into the depression of chalcopyrite flotation by sodium thioglycolate.