Selective separation of chalcopyrite and pyrite using a novel organic depressant at low alkalinity

Abstract

The selective depression effect and mechanism of the organic depressant sodium dimethyl dithiocarbamate (SDD) on pyrite in the flotation system of chalcopyrite and pyrite at low alkalinity (pH 8.5) were investigated. The results of single mineral microflotation tests indicated that the recovery efficiency of pyrite decreased from 80.23% to 39.18% after SDD was added, while the recovery efficiency of chalcopyrite decreased from 97.74% to 93.07%. This indicates that SDD has a clear selective depression effect on pyrite, but it has little depression effect on chalcopyrite. X-ray photoelectron spectroscopy (XPS) showed that at low alkalinity (pH 8.5), SDD chemical adsorbed on the surface of pyrite to form water-insoluble complexes, the flotability of pyrite surface was decreased. However, adsorption of SDD on the surface of chalcopyrite was weaker than that on pyrite, which increases the flotability difference between the two surfaces and leads to selective depression of pyrite.