Activation Mechanism of Lead Ions in Perovskite Flotation with Octyl Hydroxamic Acid Collector

Abstract

The activation mechanism of lead ions (Pb2+) in perovskite flotation with an octyl hydroxamic acid collector was systematically investigated using microflotation experiments, zeta-potential measurements, adsorption tests, Fourier transform infrared (FT-IR) analysis, and X-ray photoelectron spectroscopy (XPS) analysis. The results of microflotation experiments and adsorption tests indicate that the presence of Pb2+ can promote the adsorption of octyl hydroxamic acid (OHA) on the perovskite surface and enhance the flotability of perovskite under weakly acidic conditions. The maximum recovery of 79.62% was obtained at pH 6.5 in the presence of Pb2+, and the maximum recovery of 57.93% was obtained at pH 5.7 without Pb2+. At pHs below 7, lead species are mainly present as Pb2+ and PbOH+ in the solution; besides this, the relative content of titanium increases on the perovskite surface. The adsorption of Pb2+ and PbOH+ on the perovskite surface makes the zeta-potential of perovskite shift positively, and increases the number of activated sites on the perovskite surface. FT-IR and XPS analyses confirm that OHA chemisorbs on the surface of Pb2+-activated perovskite and forms hydrophobic Pb-OHA complexes, which improve the flotability of perovskite.