Abstract:The effect of O₃ oxidation on the flotation recovery of chalcopyrite and molybdenite was investigated. The results of single-mineral flotation tests showed that under the conditions that O₃ concentration was about 90 g/m³ and the gas flow rate was 4 L/min, after chalcopyrite and molybdenite were oxidized for 2 min, the flotation recovery of the chalcopyrite dropped to 16%, while the flotation recovery of molybdenite did not change much. The results of flotation tests for the artificially mixed ores showed that O₃ oxidation pretreatment could replace the Na₂S reagent as a chalcopyrite depressant in the selective flotation separation of chalcopyrite and molybdenite. The contact angle measurements revealed that the O₃ oxidation treatment selectively rendered the surfaces of the chalcopyrite to be hydrophilic. The Zeta potential and X-ray photoelectron spectroscopy analyses revealed that the chalcopyrite surface most likely became hydrophilic due to the formation of water-insoluble hydrophilic oxides and hydroxides on the mineral surface after the oxidation treatment. In addition, although the surface of the molybdenite was slightly oxidized, its surface remained good hydrophobicity.

Key words: chalcopyrite; molybdenite; O₃ oxidation; selective flotation; hydrophilicity