A review on the electrochemistry of galena flotation

Abstract

Galena is the most important lead-containing mineral that has semiconductor properties which can cause electrochemical reactions during flotation. This paper reviews studies of galena electrochemical flotation behavior. The electrochemical mechanisms on galena surfaces of oxidation, collector adsorption and depression are described. Collectorless flotation requires a moderate oxidizing potential, and flotation cannot be achieved under reducing conditions. The hydrophobic entity of the galena surface for collectorless flotation may be elemental sulfur, lead polysulfide or the deficiency of lead. Chemisorbed xanthate, lead dixanthate, or dixanthogen may be responsible for xanthate-induced flotation. The flotation behavior can be optimized by adjusting and controlling pulp potential, dissolved O2, and solution pH. The addition of depressants can be directly involved in redox reactions between collectors and sulfide minerals, thereby depressing galena flotation. The grinding environment also greatly influences galena flotation. Various factors such as galvanic interactions, grinding media, gas atmosphere, solution pH, and hydrogen peroxide (H2O2) formation can affect the extent of electrochemical reactions. This review proposes that research on sulfide mineral flotation should focus on the combination of theory and application of electrochemistry.