Study and proposal of a flotation technology for Zinc Oxide Ore from the Cho Dien deposit

Abstract

In recent years, the rapid decline in both reserves and quality of domestic zinc sulfide ores-the primary raw material for zinc metal production in Vietnam-has posed significant challenges for the industry. This has made the development of alternative processing technologies for low-grade zinc oxide ores (5÷10% Zn) increasingly urgent. The Cho Dien deposit (Thai Nguyen province) hosts such ores, which are strongly weathered, fine-grained, and mineralogically complex, containing smithsonit, hemimorphit, and chalcophanite with goethite, clays, and carbonates as major gangue minerals. This study investigates flotation performance under different processing regimes, including desliming versus non-desliming, reagent schemes, and flotation machine types. Experimental results demonstrate that a reagent combination of Na₂S_Tan-X_Sep-X, combined with non-desliming, is more effective than conventional depressants and dispersants. Moreover, a comparison between conventional mechanical flotation and forced-air flotation cells (TankCell) shows that TankCell achieves a zinc concentrate grading 21.75% Zn with a recovery of 62.7% after a single cleaning stage, whereas mechanical flotation requires two cleaning stages to obtain a concentrate of 21.18% Zn at 62.5% recovery. These findings confirm that flotation is a technically feasible route for complex low-grade zinc oxide ores in Vietnam and provide a practical basis for industrial application