<i>In-situ</i> Stability and Remediation of Typical Antimony (Sb) Tailings by Combined Solid Waste in Southwest China

Abstract

To explore the feasibility of reusing solid waste to stabilize high-content arsenic (As) and antimony (Sb) tailings, red mud, fly ash, dried sludge, ferrous sulfate (FeSO 4 ), and rice husk ash (RHA) were used as the stabilizer to stabilize the Sb tailings in Qing Long and Du Shan. The combined treatment with 5% red mud, 10% fly ash, 5% dried sludge, 1% FeSO 4 , and 1% rice husk ash had the best stabilization effects on As and Sb, the leaching concentrations of As and Sb decreased considerably under neutral conditions, this indicates that the leaching behavior of As and Sb is controlled by the alkaline and acid-retarding capacity of the materials. In addition, the leaching of heavy metals decreases with the formation of (C-S-H) and calcite (CaCO 3 ), indicating that heavy metals exist in the form of metal hydration or hydroxide and precipitate on the surface of calcium silicate hydrate (C-S-H) and calcite particles. Leaching of heavy metals in stabilized materials can be considered as a pH-dependent and control process of stabilization products.