Comparative studies of flotation and adsorption of Pb(II)/benzohydroxamic acid collector complexes on ilmenite and titanaugite

Abstract

In this study, the flotation and adsorption of Pb(II)/benzohydroxamic acid (BHA) complexes on the surfaces of ilmenite and titanaugite were compared to achieve their separation flotation. Single and synthetic mixed mineral flotation tests, zeta potential measurements, Fourier-transform infrared (FTIR) spectroscopy, as well as microcalorimetry analyses were carried out. The results of the flotation tests indicated that the separation of the minerals is feasible by using complexes with the molar ratio of Pb(II):BHA = 1:3 at pH = 6.0. Moreover, the Pb/BHA complexes exhibited better performance than sequentially added Pb(II) and BHA species. The zeta potentials indicated that Pb/BHA complexes might selectively adsorb on the surface of ilmenite in the mixed system. The FTIR results demonstrated that the Pb/BHA complexes exhibited higher adsorption capacity on the surface of ilmenite than by sequential dosing of Pb(II) and BHA. In contrast, on the titanaugite surface the adsorption ability of Pb/BHA complexes was similar to that of BHA, indicating that titanaugite could not be activated by Pb(II) ions. The microcalorimetric results revealed that the adsorption heats on the surfaces of ilmenite and titanaugite were ranked as Pb/BHA > BHA > Pb(II) ions, indicating that Pb/BHA complexes interacted most strongly with the two mineral surfaces, and chemisorption occurred on both surfaces by using BHA and Pb/BHA collectors. Thermodynamic analysis revealed that complexes with BHA are easier to generate when using Pb(II) than Ca2+ and Fe2+ ions, and the Pb/BHA complexes preferred to adsorb on the active sites of ilmenite (e.g. Fe2+ or Fe3+) rather than titanaugite (e.g. Ca2+), indicating that selective separation is feasible.