Investigation of the characteristics of stibnite (Sb₂S₃) flotation tailings and extraction of critical metals (Sb and As): Optimization and scale-up

The supply of metals is increasingly challenged by high demand for raw materials and the depletion of high-grade ore deposits. In addition, the management of tailings from metal processing remains a persistent problem in the mining sector. This study aims to characterize stibnite tailings and develop a hydrometallurgical process for the recovery of antimony, arsenic, and iron and the removal of sulfide minerals from these tailings. The main minerals identified were stibnite, pyrite, and a small amount of arsenopyrite, together with associated gangue minerals such as quartz and muscovite. Optimum conditions were set as follows: 4.4 M HCl, 0.5 M NaNO₃, 25 % pulp density, 70 °C temperature, and 1-hour leach time. Under these conditions, flask leaching tests achieved remarkable leaching efficiencies of 99.88 % for Sb, 99.90 % for As, and 99.95 % for Fe. Bench scale experiments (1L reactor) showed high leaching efficiencies of 99.70 % for Sb, 97.50 % for As, and 97.00 % for Fe. Finally, leaching efficiencies of 98.30 % for Sb, 92.00 % for As, and 98.00 % for Fe were successfully achieved in semi-pilot tests (10 L reactor).