Enhancement of the Collectorless Flotation of Oxidized Chalcopyrite by Quartz Particles

The collectorless flotation of chalcopyrite has the potential to facilitate the efficient separation of Cu–Mo and Cu–Ni ores while reducing reagent consumption. This process relies on the natural hydrophobicity of the chalcopyrite surface, which can be adversely affected by surface oxidation. Quartz, a ubiquitous gangue mineral in chalcopyrite flotation systems, is widely present throughout flotation circuits. In this study, the effects of quartz particles of varying sizes on the surface properties and flotation behavior of chalcopyrite under different oxidation conditions were systematically investigated through micro-flotation experiments, contact angle measurements, X-ray photoelectron spectroscopy (XPS), and particle size analysis. The results indicate that hydrophilic iron (oxy)hydroxide species readily form on oxidized chalcopyrite surfaces, leading to reduced floatability. The presence of quartz particles was associated with a reduction in the abundance of surface iron (oxy)hydroxide species and an improvement in collectorless flotation performance. These findings suggest that interactions between quartz and chalcopyrite may mitigate the adverse effects of surface oxidation. They also highlight the potential of collectorless pre-flotation strategies for copper ore processing.