Use of Pb2+ as a Selective Activator in Selective Flotation Separation of Specularite, Aegirine, and Chlorite: A DFT Study

Abstract

Despite being one of the main sources of iron, specularite is often associated with gangue minerals such as aegirine and chlorite. Flotation separation is challenging in the mineral processing industry because of the similar surface properties of specularite, aegirine, and chlorite. This study investigates the role and selective activation mechanism of Pb2+ in the flotation separation of specularite, aegirine, and chlorite using micro-flotation experiments, solution chemistry calculations, zeta potential analysis, and the density functional theory (DFT). The results of the micro-flotation experiments show that the addition of lead ions can significantly improve the floatability of specularite, but has little impact on the floatability of aegirine and chlorite. Additionally, the solution chemistry calculations results show that PbOH+ is the main component of selectively activated specularite. The zeta potential analysis shows that Pb2+ is more inclined to adsorption on the surface of specularite, and that more collectors are adsorbed on the surface of specularite after the addition of Pb2+. Finally, the DFT calculations show that different chemical bonds are formed during the interaction between CuOH+ and the mineral surface, resulting in different adsorption energies.