Abstract:Based on wet zinc smelting atmospheric leaching slag and oxygen pressure leaching slag (both of hazardous waste) of high-sulfur mixing slag, effects of thermal roasting reaction factors (temperature, sulfur content, etc.) on curing effect of heavy metals in the slag were studied. BCR continuous extraction method was used to study the chemical speciation distribution of heavy metals in slag before and after roasting. The results show that toxic leaching results of Zn, Pb, As, and Cd in slag can meet the national standard, and the slag rate can be reduced to about 70% under the conditions including roasting temperature of 1 000 ℃, sulfur mass fraction in mixed material of 20%, air flow rate of 1.6 m3/h, and roasting time of 7 h. The main chemical forms of Zn, Pb, As and Cd in slag after roasting and heat treatment are relatively stable residue form. It can provide a theoretical basis for low-cost harmless and reduction treatment of zinc wet smelting slag.