Utilization of lead ions to improve surface hydrophobicity and flotation recovery of sulfidized smithsonite

Abstract

Zinc oxide minerals often coexist with lead minerals in ores, and lead ions (Pb2+) dissolve from lead minerals during grinding and slurry stirring. These dissolved Pb2+ ions affect the surface properties of zinc oxide minerals and the interaction between the mineral surface and flotation reagents, causing a change of the flotation behavior of the zinc oxide minerals. In this study, we systematically investigated the effect of Pb2+ on the surface hydrophobicity and flotation behavior of sulfidized smithsonite in xanthate flotation. The smithsonite floatability was enhanced when Pb2+ was present in the pulp after sulfidization, and the flotation recovery increased from 50.05% to 82.88%. Surface measurements indicated that the sulfide content on the smithsonite surfaces was higher for the smithsonite–Na2S–Pb2+ system than for the smithsonite–Na2S system, and the distribution of the sulfidization products was more compact. Furthermore, by addition of Pb2+ after sulfidization, the characteristic peak of xanthate appeared in the infrared spectrum of smithsonite, and the smithsonite contact angle increased from 36.38° to 60.35°. Therefore, interaction of Pb2+ with the sulfidized smithsonite surfaces enhanced the surface reactivity and promoted xanthate adsorption, thus improving the surface hydrophobicity, and creating favorable conditions to obtain an ideal flotation index.