Pb ion Pre-Modification enhances the sulfidization and floatability of smithsonite

Abstract

Compared with copper and lead oxide, zinc oxide often requires activation for it to be effectively enriched during sulfidization–xanthate flotation. We investigated the effect of Pb ion pre-modification on the surface structure, sulfide layer properties, and floatability of smithsonite. Pb ion pre-modification facilitated the floatability. X-ray photoelectron spectroscopy indicates that Pb carbonates formed on the pre-modified surface via ion exchange with Zn ions of the mineral surface. In addition to the common Zn–S species, Pb carbonates reacted with S ions to transform into essential Pb–S species during sulfidization. Visual MINTEQ modeling and thermodynamic calculations suggest that in smithsonite pulp treated with Pb ions and S ions, the main sulfide products of the ionic interactions were PbS and ZnS, but the formation trend of PbS was much higher than ZnS. As per adsorption tests, although Pb ion pre-modification did not considerably increase the adsorption density of S ions, pre-modification can reduce desorption of S ions on the smithsonite surface. This confirms that Pb ion pre-modification can considerably strengthen the stability of the sulfide layer. Therefore, Pb ion pre-modification improves the sulfidization and flotation recovery of smithsonite.