Comparative study of the interaction mechanisms between galena, cerussite and anglesite with benzohydroxamate and octanohydroxamate in aqueous solution

Abstract

• The interaction mechanisms between lead ores with hydroxamate anions were suggested. • The identity of the formed metal complexes was determined by FTIR . • A lower BHA adsorption density on the lead active sites was found compared to OHA. • The collector anions are chemically adsorbed in most of the studied conditions. • Both anionic collectors are physisorbed onto anglesite conditioned at pH 5. Chelating agents have currently received particular attention in the search for reagents to improve the separation of oxidized minerals by froth flotation. Among chelating reagents, the hydroxamic acids outstand because they have shown a higher performance without the health, safety and environmental (HSE) concerns associated with the xanthates. In this study, the chemical adsorption of benzohydroxamic acid (BHA) and octanohydroxamic acid (OHA) onto galena (PbS), cerussite (PbCO 3 ) and anglesite (PbSO 4 ) surfaces was evaluated making use of infrared spectroscopy. Likewise, zeta potential measurements were carried out to determine the surface charge of the mineral particles before and after conditioning with the surfactant. Finally, the interaction mechanisms between galena, cerussite and anglesite with hydroxamate anions in aqueous solution were suggested; these mechanisms present the global reactions and help to understand the interaction of BHA and OHA with lead ores. It is suggested that the bezohydroxamate and octanohydroxamate anions are chemically adsorbed on the lead mineral surface in most of the studied conditions, except on the anglesite conditioned at pH 5, where the referred anions are physisorbed. The results obtained from infrared spectroscopy and zeta potential measurements suggest that P b 2 + dissolves from the crystal lattice and reacts with the anions to precipitate Pb–benzohydroxamate or Pb–octanohydroxamate, which are physically readsorbed on the anglesite surface vicinity. Additionally, the identity of the formed metal complexes was determined.