Flotation separation of bastnaesite and fluorite using styrylphosphonic acid and cinnamohydroxamic acid as collectors

Light rare earth elements (LREEs) with atomic numbers 57 to 60 (lanthanum (La), cerium (Ce), praseody-mium (Pr) and neodymium (Nd)) have diverse applications in many fields. Bastnaesite is an important LREE-containing mineral and flotation is a most important method to recover fine grained bastnaesite and to separate bastnaesite and its associated gangue minerals such as fluorite. This study firstly employed styrylphosphonic acid (SPA) and cinnamohydroxamic acid (CHA) with the same nonpolar group (i.e., styryl group) as SPA as the collectors in the flotation separation of bastnaesite and fluorite. Flotation experiments show certain selectivities of SPA and CHA. And CHA has the stronger collecting ability and the poorer selectivity than SPA. The adsorption mechanisms of SPA and CHA on the surfaces of bastnaesite and fluorite were investigated by zeta potential measurements, infrared spectroscopic and X-ray photoelectron spectroscopic tests as well as first-principles calculations. Zeta potential measure-ments show the greater shift in the zeta potential of bastnaesite caused by the addition of CHA than SPA, which indicates the stronger affinity of CHA on the surface of bastnaesite than SPA, as confirmed by the higher adsorption energy of CHA on the surface of bastnaesite obtained from first-principles calculations.(c) 2022 Elsevier B.V. All rights reserved.