Determining the lead-sulfur species formed on smithsonite surfaces during lead-ion enhanced sulfidation processing

In this study, microflotation experiments, as well as inductively coupled plasma-atomic emission spectrometry (ICP-AES), X-ray photoelectron spectroscopy (XPS), localized electrochemical impedance spectroscopy (LEIS), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were used to understand the influence of lead ions on smithsonite flotation during sulfidation processing and determine the lead sulfur species formed on the mineral surface. Lead ions significantly improve smithsonite recovery in microflotation experiments. The depletion of lead ions and the clear reduction in the concentration of sulfur ions in solution indicate that lead ions act as activators that greatly modify the smithsonite surface during sulfidation processing. XPS showed that lead-sulfide complexes and PbCO3 form on the mineral surface. These lead-sulfide complexes exist in the forms of lead monosulfide and lead polysulfide. PbS+, PbS2﹣, and PbS3﹣ species were detected on the smithsonite surface by TOF-SMIS, and the increase in the level of CO3– observed by TOF-SMIS further indicates that PbCO3 was formed after lead-ion activation of the smithsonite. The increased impedance observed by LEIS is due to the formation of PbCO3 and lead-sulfide complexes on the smithsonite surface and the formation of large amounts of lead-sulfide complexes promote smithsonite flotation.