A novel approach for selective flotation separation of chalcopyrite and molybdenite – Electrocatalytic oxidation pretreatment and its mechanism

Abstract

Electrocatalytic oxidation was adopted as a novel pretreatment method for the following selective flotation separation of chalcopyrite and molybdenite. Flotation tests of single mineral and artificial mixed ores were performed after the pretreatment of electrocatalytic oxidation, and surface analysis of the both minerals before and after the pretreatment was characterized by water contact angle, zeta potential, X-ray photoelectron spectroscopy (XPS) and field emission electron probe microanalyzer (EMPA) measurements. Flotation results showed that molybdenite could be efficient separated from chalcopyrite in the artificial mixed ores regardless of the mass ratio. Surface analysis showed that chalcopyrite was strongly depressed due to the hydrophilic oxidation products (e.g., CuO, Cu(OH)2, FeOOH and Fe2(SO4)3) were formed and precipitated on its surface after the pretreatment of EO, sharply reducing its floatability. However, the water contact angles of molybdenite surface changed hardly attributed to the rapid dissolution of oxidation products (e.g., MoO42− and SO42−) into the pulp under alkaline condition, making it keep good floatability. A highly efficient flotation separation of chalcopyrite and molybdenite was obtained via the pretreatment of electrocatalytic oxidation. Therefore, electrocatalytic oxidation pretreatment can be employed as a promising alternative for the toxic depressants of copper sulfides.