Effects of seawater on the adsorption of xanthate onto galena and sphalerite

Abstract Seawater contains divalent calcium and magnesium cations. Under alkaline conditions, calcium and magnesium ions react with hydroxide ions to form insoluble hydroxyl complexes or hydroxide precipitates. The hydrophilic substances that may be adsorbed on the mineral surface during the flotation process hinder the adsorption of the collector, affecting mineral hydrophobicity, and thus reducing the floatability of the mineral. In this study, the effects of seawater on the adsorption of xanthate onto galena and sphalerite were investigated. The results show that under strong alkaline conditions, seawater has significant and slight adverse effects on sphalerite and galena, respectively. Flotation regulators such as ethylenediamine tetraacetic acid, sodium hexametaphosphate, and sodium silicate can eliminate the adverse effect on galena and sphalerite flotation to a certain extent. The mechanisms were revealed through microflotation experiments, contact angle measurements, bubble-particle attachment tests, zeta potential measurements, and XPS analysis.