The recycling of tailings wastewater leads to the introduction of inevitable ions in the flotation environment, changes the physical and chemical properties of mineral surface, and affects the mineral flotation index.In order to explore the influence of Ca²⁺and Mg²⁺on galena flotation, the influence rule and mechanism of Ca²⁺and Mg²⁺on galena flotation are studied by single mineral flotation experiment, calculation of flotation solution chemistry, Zeta potential analysis of galena surface, XPS detection analysis and other methods.The results of single mineral flotation experiment show that both Ca²⁺and Mg²⁺can inhibit the flotation effect of galena.When Ca²⁺concentration increases from 0 mg/L to 250 mg/L, the recovery rate of galena decreases by 6.5%.Under the same conditions, the recovery rate of galena decreases by 9% when Mg²⁺exists.Calcium is mainly adsorbed on the surface of galena in the form of Ca²⁺and CaOH⁺, and CaOH⁺will bind with some S atoms on the surface of galena to enhance its surface hydrophobicity, thus reducing the floating rate of galena.The reason why Mg²⁺in the strong alkaline pulp reduces the recovery rate of galena is that Mg²⁺is adsorbed on the surface of galena in the form of magnesium hydroxide precipitation to enhance its hydrophobicity, and Ca²⁺and Mg²⁺are both chemically adsorbed on the surface of galena.