Review: Removal of Thiosalt/Sulfate from Mining Effluents by Adsorption and Ion Exchange

Thiosalts are generated as intermediate products in the oxidation of sulfide ores. Thiosalts have relatively low toxicity, however sulfate formed from the degradation of thiosalts, leads to pH depression in receiving water bodies creating toxic conditions for aquatic organisms. Therefore, proper management and treatment of mining effluent water containing thiosalts is critical. This article briefly discusses Acid Mine Drainage (AMD), different sulfur species present in AMD, behavior of thiosalts as a function of pH and temperature, and thiosalt treatment methods including natural degradation, chemical, and biological oxidation. Carbonaceous adsorbents, ion-exchange resins and other adsorbent approaches are discussed in detail.