Microscale exploration of the sulfidization flotation theory in malachite

[Display omitted] •The surface changes during the malachite sulfidization process at the microscale were explored using various advanced techniques.•The in-situ change in malachite surface morphology after reagents adsorption was directly observed using AFM.•The effect of sulfide film formation on the interaction force between malachite particles and bubbles was determined. With the gradual depletion of copper sulfide resources, efficient flotation technologies for the recovery of copper oxide minerals, such as malachite, have received significant attention. Although sulfidization plays a critical role in malachite flotation, the fundamental theory of sulfidization flotation remains uncertain in the context of practical industrial applications. In this study, evolution of the sulfide product morphology on the malachite surface was observed after treatment with various concentrations of sodium sulfide. In addition, the valence states and phase compositions of the sulfide products were investigated using different X-ray techniques. Furthermore, the evolution of the malachite surface morphology after the formation of a sulfide film was investigated, as were the interaction forces between the malachite and bubbles under the action of butyl xanthate. As a result, it was possible to directly observe the growth process of the sulfide film on the malachite surface, and the presence of Cu(I) was confirmed in the sulfide products. Moreover, the compositions of the sulfide products were investigated using X-ray techniques. The obtained results demonstrated that the sulfide film facilitated the formation of butyl xanthate product layers on the malachite surface, whilst also enhancing the interfacial interaction forces between the malachite and the bubbles.