Enhancing monazite flotation performance with octyl hydroxamic acid collector (OHA) by introducing Pb2+ to the solution

Abstract

Though octyl hydroxamic acid (OHA) has been extensively employed as the collector for monazite flotation, the weak collecting ability that OHA exhibits calls for improvement. In this article, the researchers systematically investigated the beneficial effects and mechanism of Pb²⁺ for flotation process of monazite. We commenced with micro-flotation tests, which indicated that the presence of Pb²⁺ could effectively promote the floatability of monazite with OHA. Specifically, at pH ≈ 8, the flotation recovery of monazite could reach 72.36 % following the addition of Pb²⁺. Meanwhile the hydrolyzing species of Pb adsorbed onto monazite particle surfaces, rendering more active sites for OHA absorption. Subsequently, by means of zeta potentials, Fourier transform infrared analysis (FTIR), and X-ray photoelectron spectroscopy (XPS), the researchers revealed that OHA underwent a reaction between Pb²⁺ species and active Ce sites to form the complexes (Ce-O-Pb) on monazite particle surfaces, which further produced the hydrophobic OHA-Pb chelates.