Effect of surface modification by lead ions on flotation behavior of columbite-tantalite

Ta and Nb are listed in the category of strategic metals. Columbite-tantalite is the most abundant Nb- and Ta-containing mineral. The flotation is a promising method for fine columbite-tantalite recovery. However, few studies have been performed on the surface modification and enhanced flotation recovery of columbite-tantalite in presence of benzohydroxamic acid (BHA). This study systematically investigates the surface modification of columbite-tantalite by Pb 2+ ions and its effect on columbite-tantalite flotation with BHA as collector. The results show that the Pb 2+ modification enhances the adsorption of BHA on the columbite-tantalite surface, increases its hydrophobicity , and consequently improves floatability. Zeta potential measurement and X-ray photoelectron spectroscopy (XPS) analysis reveal that the Pb ionic species (Pb 2+ and PbOH + ) interact with the columbite-tantalite surface via electrostatic attraction and chemical interaction, generating new active products on the mineral surface, i.e., –O–Pb complexes. The –O–Pb complexes exhibit strong reactivity toward BHA subsequently introduced into the flotation pulp. This leads to a significant improvement in the chemisorption of BHA on the Pb 2+ -modified columbite-tantalite surface. As a surface modification method, introducing Pb 2+ ions can effectively activate the columbite-tantalite surface and increase its floatability.