Experimental and molecular dynamics simulation insights into enhanced flotation of sulfidized smithsonite in a Cu–Pb dual activation system

Abstract

The limited active sites on the smithsonite surface pose significant challenges to the interaction between collectors and the mineral surface, resulting in suboptimal flotation recovery. This study investigates the influences of Pb 2+ and Cu 2+ on the reactivity, sulfidized components, and collector adsorption on the sulfidized smithsonite surface. Flotation results demonstrated that metal ions significantly improved the flotation behavior of sulfidized smithsonite. With Cu 2+ or Pb 2+ activation, the flotation recovery of sulfidized smithsonite reached 80.42% and 84.52%, respectively. Notably, surface activation was further enhanced in the Cu–Pb co-activation system, achieving a flotation recovery of 97.69%. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) confirmed an increase in sulfidization products on the smithsonite surface following activation with either Pb 2+ or Cu 2+ , with further enhancement observed in the Cu–Pb co-activation system. Atomic force microscope (AFM) and scanning electron microscope (SEM) revealed morphological changes and variations in elemental content, demonstrating the formation of substantial Cu and Pb sulfidized components on the smithsonite surface in the Cu−Pb co-activation system. Molecular dynamics simulations indicated that the relative concentrations of HS − and metal ions were higher near the smithsonite in the Cu–Pb co-activation system than in the single metal ion activation system. The improved adsorption behavior of the collector on the sulfidized smithsonite surface following Cu–Pb co-activation was confirmed through Fourier transform infrared (FTIR) analysis, adsorption measurements, and contact angle tests. Results reveal that Cu–Pb co-activation remarkably enhances potassium pentyl xanthate (KAX) adsorption on the sulfidized smithsonite surface, providing an innovative approach for improving smithsonite flotation.