Surface oxidation modification mechanism of sodium persulfate on arsenopyrite and its impact on the flotation separation of bornite and arsenopyrite

Bornite and arsenopyrite are common sulfide minerals in copper ores. The similar physicochemical properties of these minerals pose challenges for their effective separation through traditional flotation methods. This study systematically investigated the impact of sodium persulfate (Na 2 S 2 O 8 ) treatment on the flotation performance of both bornite and arsenopyrite through single-mineral and artificially mixed mineral flotation tests. The artificially mixed flotation experiment revealed that at an initial pH of 4, a Na 2 S 2 O 8 concentration of 5 × 10 −3 mol/L and NaBX (5 × 10 −5 mol/L), bornite and arsenopyrite exhibited recoveries of 80.01 % and 24.04 %, respectively. The effects of Na 2 S 2 O 8 on mineral surfaces were analyzed through contact angle measurement, atomic force microscopy, scanning electron microscopy–energy dispersive spectroscopy, zeta potential measurement, and local electrochemical impedance spectroscopy. The results confirmed that Na 2 S 2 O 8 treatment significantly altered the arsenopyrite surface but had a small impact on the bornite surface. X-ray photoelectron spectroscopy analysis revealed that Na 2 S 2 O 8 treatment generated numerous hydrophilic oxides on the arsenopyrite surface, such as sulfates and arsenates, which increased its hydrophilicity and reduced floatability. This study provides theoretical insights into the separation of copper and arsenic in copper ores to reduce environmental pollution.