Research on the leaching characteristics of heavy metals in antimony tailings in Weishan, Yunnan

China is the world’ s largest producer of antimony, and the ecological risks it brings cannot be ignored. Taking a certain antimony tailings in Weishan, Yunnan as the research object, the heavy metal content is tested, and the toxicity leaching method of synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP) is used to conduct leaching experiments on the tailings. The pH-sequencing batch experiment is conducted to explore the influence of pH on the leaching concentration of antimony in tailings. The experimental results show that the tailings contain excessive amounts of heavy metals Sb, As, and Cd, with Sb being 13 times higher than the maximum allowable concentration of soil antimony in the World Health Organization (36 mg·kg^-1), As being about 14 times higher than the limit value in the Soil Environmental Quality Standards (25 mg·kg^-1), and Cd being about 9 times higher. The two toxicity leaching methods (SPLP and TCLP) show that only Sb leaching exceeds the standard, while other heavy metals do not exceed the standard. The SPLP leaching concentration is higher than that of TCLP, indicating that SPLP is more suitable for Sb leaching, consistent with previous results. The leaching concentration of Sb exceeds the industrial pollutant discharge standard limit, but the risk level is not high. The leaching concentration of As in both methods is far below the limit value of 5 mg·L^-1. The results of the pH-sequencing batch experiment show that the pH of the tailings has a significant impact on the leaching of antimony, with a V-shaped pattern. The leaching concentration of Sb begins to increase significantly at pH < 1. 3 and pH > 11. 5.