Beneficial effects and mechanism of lead ions for bastnaesite flotation with octyl hydroxamic acid collector

The beneficial effects and mechanism of Pb ions (Pb2+) for bastnaesite flotation were systematically investigated. The results of micro-flotation tests indicated that the Pb2+ effectively enhanced the floatability of bastnaesite with octyl hydroxamic acid (OHA) collector. Maximum recovery of 67% was obtained at pH 8-9. Adsorption of the hydrolyzing species of Pb occurred at this pH, which provided more active sites on the bastnaesite surface for OHA absorption. Furthermore, lead species interacted with active Ce sites to form lead containing complexes (Ce-O-Pb) on the bastnaesite surface, and the hydrophobic Pb-OHA chelates were formed via chemical adsorption between Pb2+-activated bastnaesite and OHA. These findings were confirmed by adsorption measurements, zeta-potential measurements, Fourier transform infrared analysis (FT-IR), and X-ray photoelectron spectroscopy (XPS).