Abstract:In order to screen out the composite passivation materials suitable for the remediation of arsenic (As) cadmium (Cd) contaminated soil around non-ferrous metal smelters, 2,4,6-trimine trisodium (TMT), iron salt, clay minerals and aluminum-based material were selected and the optimal compound formula for Cd and As passivation was studied. The results showed that under the same test conditions, after adding three passivation materials: C1 (clay mineral + TMT), C2 (calcium, magnesium and phosphorus fertilizer + iron salt + zeolite + TMT), C3 (iron salt + aluminum-based material + TMT),the concentrations of acid soluble As and Cd in the soils around the non-ferrous metal smelter had reached the Category IV Standard of GB 3838—2002 "Environmental Quality Standard for Surface Water". With the passage of time, adding 1.0% C3 had the best passivation effect. Among them, the reduction rates of acid soluble As and Cd concentrations could be up to 96.95% and 99.37%, respectively. Tessier five-step extraction analysis showed that C3 slowly transferred the forms of As and Cd from the exchangeable form and iron-manganese oxide combined form to the residual form, suggesting its effect of passivating As and Cd at the same time, thus could reduce the migration ability of As and Cd, and reduce the pollution risk of As and Cd in the environment around the smelter.