Effect of Zn²⁺ and Tannic Acid as Combination Inhibitors on the Flotation Separation of Fluorite and Calcite

Objective The co-associated fluorite ore has the characteristics of fine embedding particle size and complex associated conditions. Developing an environmentally friendly and efficient inhibitor is of great significance for fluorite sorting. Method This article focuses on the fluorite and calcite, the optimal ratio, dosage, and pH value conditions of Zn²⁺-tannic acid combination inhibitor in the sodium oleate collector system were determined through single mineral flotation experiments. The mechanism of selective inhibition of calcite by Zn²⁺-tannic acid combination inhibitors was explained through adsorption capacity testing, Zeta potential testing, UV-Vis testing, and XPS testing. Result The flotation test results show that compared to tannic acid, the Zn²⁺-tannic acid combination inhibitor has a stronger ability to selectively inhibit calcite at neutral and weakly alkaline conditions. The difference in recovery rates between the two minerals increased from 56.51% to 80.01%. The results of adsorption capacity tests, Zeta potential tests, and UV-Vis tests indicate that Zn²⁺- tannic acid complexes in combination inhibitors can selectively adsorb on the surface of calcite. The XPS results indicate that the adsorption of Zn²⁺- tannic acid complex on the surface of calcite is stronger than that of tannic acid. Conclusion This study provides a reference for the efficient separation of calcite type fluorite ores.