A novel activation method for regulating surface characteristics and flotation performance of smithsonite: XPS, SEM-EDS, AFM, ToF-SIMS and FT-IR studies

Smithsonite is a typical zinc oxide mineral, and the flotation index is not ideal for the recovery of smithsonite via sulfidization–xanthate flotation. In this study, Pb2+ was used as an activator for the stepwise activation of smithsonite in a sulfidization–xanthate flotation system. Micro-flotation tests and various surface analytical assays were employed to investigate the effects of Pb2+ stepwise activation on the flotation behavior and surface properties of smithsonite. The micro-flotation tests revealed that the flotation recovery of smithsonite reached 90.26 % after the stepwise activation of Pb2+ at an appropriate concentration. X-ray photoelectron spectroscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy, atomic force microscopy, and time-of-flight secondary ion mass spectrometry indicated that abundant active sites of Pb components appeared on the smithsonite surface after Pb2+ stepwise activation, which promoted the adsorption of S ions on the smithsonite surface. The increase in the proportion of the PbS component after sulfidization effectively enhanced the reaction activity of the mineral surface. Fourier-transform infrared spectroscopy and contact angle measurements showed that xanthate could be stably adsorbed on the smithsonite surface after Pb2+ stepwise activation, thereby enhancing the surface hydrophobicity and flotation behavior of smithsonite. Therefore, Pb2+ stepwise activation can promote sulfidization on the smithsonite surface, improve the reactivity and hydrophobicity of the mineral surface, and substantially increase the flotation index of smithsonite.