Flotation behaviors of chalcopyrite and galena using ferrate (VI) as a depressant

This paper investigated the effects of potassium ferrate (PF) on the flotation performances of chalcopyrite and galena. The flotation results showed that PF obviously depressed galena, but had little effects on the floatability of chalcopyrite within pH range of 4.0–12.0. Zeta potential tests showed that the addition of PF induced the formation of more amounts of hydrophilic species on the surface of galena under an alkaline environment. Industrial grade O-isopropyl-N-ethyl thionocarbamate (IPETC) chemically adsorbed on the surface of the PF-treated chalcopyrite and galena after its addition. Contact angle measurements showed that with the addition of PF, the contact angle of the galena surface significantly decreased compared with the chalcopyrite surface. Localized electrochemical impedance spectroscopy (LEIS) tests showed that the addition of PF increased the impedance of the galena surface. X-ray photoelectron spectroscopy (XPS) analyses revealed that the formation of hydrophilic species, namely lead sulfite, lead hydroxide and ferric hydroxide, on the galena surface, decreased its floatability in the presence of PF, while the formation of hydrophobic species, namely copper disulfide and elemental sulfur, on the chalcopyrite surface, maintained its floatability. Finally, a descriptive model for the reaction of PF with chalcopyrite and galena was proposed.