Release characteristics and stabilization of heavy metals in antimony tailings in Yunnan Province, China

The pollution caused by the mining and smelting of heavy metals is becoming an increasingly severe environmental problem. In this study, the environmental risks of mine tailings were explored using typical antimony tailings (the depth of the sample taken from the ground to the deepest position of 120 cm) from the Zuoxiguo mine in Yunnan Province, Southwest China. The tailings were examined to explore the geological background, distribution characteristics, and release characteristics of heavy metals. Additionally, stabilizer treatments for heavy metals were investigated in consideration of waste treatment. The results showed that the contents of Sb and As (8.93x103 and 425 mg/kg, respectively) in the tailings were considerably higher than the local soil background values, suggesting that these metals pose a considerable threat to the surrounding environment. The geological background values of Cr, Cd, Pb, Cu, and Zn were relatively low. The results of static release showed that Sb, As, Cd, and Cr leached from the tailings more easily than Cu, Zn, and Pb under acidic conditions (pH=2.98). Geo-accumulation indices and potential ecological risk indices showed that Sb, As, Cd, and Pb were highly enriched in the tailings, whereas Cu, Cr, and Zn contents were relatively low. The single factor ecological risk index of the mining area showed that Sb and As are high ecological risk factors, whereas Cr, Cu, Zn, Cd, and Pb are not. The results of the orthogonal test results showed that by adding 15.0% (m/m) fly ash and 15.0% (m/m) zeolite powder to the quicklime and curing for 28 d, a significant stabilization effect was observed for Sb, As, and Pb. This study helps determine the priority control components for characteristic heavy metals in antimony tailings, and provides valuable insights regarding the formulation of appropriate mitigation strategies.