China Nonferrous Metallurgy

The waste acid emitted from copper smelting flue gas treatment has the characteristics of large emissions, high arsenic content, and complex composition. At present, calcium carbide slag is widely used as an arsenic removal agent, and the arsenic removal rate can reach about 60%, but there are problems such as large consumption of calcium carbide slag and high cost of waste acid treatment. In order to reduce the cost of waste acid treatment and reduce inventory pressure of self-produced copper slag, a copper smelter plans to use self-produced copper slag instead of purchased calcium carbide slag to remove arsenic from waste acid, and conduct exploratory experiments. The results showed that the arsenic removal rate was only 18.03% under the conditions of pH=2.19, reaction temperature 40℃, and stirring for 30 minutes, indicating that the direct arsenic removal effect of copper slag was not good; under optimized conditions, when the dosage of copper slag is 80kg/m³, the amount of hydrogen peroxide is 50L/m³, the reaction time is 6h, and the initial pH of the solution is 11, the copper slag achieves the best arsenic removal effect and the arsenic removal rate up to 99.5%. The smelter will continue to explore the process of synergistic removal of arsenic from calcium carbide slag and copper slag according to a certain ratio, and explore a technical route for arsenic removal with both technical and economic advantages.