Adsorption mechanism of a new depressant on pyrite surfaces and its application to the selective separation of chalcopyrite from pyrite

Abstract Selecting a suitable depressant that strongly depresses the pyrite flotation but has little effect on the floatability of chalcopyrite is of great significance for selectively separate chalcopyrite from pyrite. In this study, galactomannan (GM) was used to replace traditional depressants for depression of pyrite. The depression performance and adsorption mechanism of it on the pyrite surface were investigated by micro-flotation tests, zeta potential measurements, Fourier transform infrared spectroscopy (FTIR) measurements, and X-ray photoelectron spectroscopy (XPS) analyses. The results showed that, compared with guar gum, polyacrylamide (PAM), dextrin, carboxymethylcellulose (CMC), sodium hexametaphosphate (SHMP), GM had the optimum depression effect on pyrite, but had a negligible effect on chalcopyrite. A satisfactory separation of chalcopyrite and pyrite was achieved at weakly alkaline condition (pH 8), at which the flotation recovery of chalcopyrite was 86.11% and that of pyrite was only 13.85%. The results of surface analyses confirmed that GM could be selectively chemisorbed on pyrite surface through the Fe sites and impede the further adsorption of sodium butyl xanthate (SBX). The use of GM as a depressant, therefore, enabled the effective separation of chalcopyrite from pyrite.