Inhibition of galena flotation by humic acid: Identification of the adsorption site for humic acid on moderately oxidized galena surface

The influence of humic acid on the flotation of galena under different redox conditions was studied based on micro-flotation experiment. The results showed that the humic acid was an effective inhibitor for moderately oxidized galena. Adsorption tests indicated that the surface oxidation played an incredibly important role in the adsorption of humic acid on galena surface. Explorations on identifying the mechanism for the selective adsorption of humic acid on the surface of oxidized galena were carried out by Zeta potential, XPS and FT-IR analysis. The results indicated that the oxidation of galena caused significant changes in surface components, which was beneficial to the adsorption of humic acid. The elemental sulfur formed by the oxidation of galena is one of the adsorption sites for humic acid besides lead sulfate.