Effect of fluoride roasting on copper species transformation on chrysocolla surfaces and its role in enhanced sulfidation flotation

It is difficult for chrysocolla to achieve the recovery effect of sulfidation flotation, which is closely related to its mineral surface composition. The paper systematically studied the effects of fluoride roasting on the surface composition of chrysocolla, explored the impact of fluoride-roasted chrysocolla on sulfidation flotation, and discussed the mechanisms involved in both fluoride roasting and sulfidation flotation. With CaF2 as the roasting reagent, Na2S·9H2O as the sulfidation reagent, and sodium butyl xanthate (NaBX) as the collector. The results from the flotation experiments showed that fluoride roasting could improve the floatability of chrysocolla, and the recovery rate increased from 16.87% to 82.74%. X-ray diffraction analysis revealed that after fluoride roasting, almost all of the Cu on the surface of the chrysocolla was exposed in the form of CuO, which could provide a basis for subsequent sulfidation flotation. The microscopy and elemental analyses revealed that large quantities of "pagoda-like" grains were observed on the sulfidation surface of the fluoride-roasted chrysocolla, indicating high crystallinity particles of copper sulfide. This suggested that the effect of sulfide formation on the chrysocolla surface was more pronounced. X-ray photoelectron spectroscopy analysis revealed that fluoride roasting increased the relative contents of sulfur and copper on the surface, and both the Cu+ and polysulfide fractions on the surface of the minerals increased. It enhanced the effect of sulfidation, which was conducive to flotation recovery. Therefore, fluoride roasting improves the effect of copper species transformation and sulfidation on the surface of chrysocolla, promotes the adsorption of collectors, and improves the recovery of chrysocolla from sulfidation flotation.