Thermodynamic analysis and process optimization of zinc and lead recovery from copper smelting slag with chlorination roasting

An efficient chlorination roasting process for recovering zinc(Zn)and lead(Pb)from copper smelting slag was proposed.Thermodynamic models were established,illustrating that Zn and Pb in copper smelting slag can be efficiently recycled during the chlorination roasting process.By decreasing the partial pressure of the gaseous products,chlorination was promoted.The Box−Behnken design was applied to assessing the interactive effects of the process variables and optimizing the chlorination roasting process.CaCl_(2) dosage and roasting temperature and time were used as variables,and metal recovery efficiencies were used as responses.When the roasting temperature was 1172℃ with a CaCl_(2) addition amount of 30 wt.%and a roasting time of 100 min,the predicted optimal recovery efficiencies of Zn and Pb were 87.85%and 99.26%,respectively,and the results were validated by experiments under the same conditions.The residual Zn-and Pb-containing phases in the roasting slags were ZnFe_(2)O_(4),Zn_(2)SiO_(4),and PbS.

Smelting chlorination method applied to removal of copper from copper slags

In order to reasonably utilize the iron resources of copper slags, the smelting chlorination process was used to remove copper from copper slags. Higher holding temperature and O2 flow rate are beneficial to increasing copper removal rate. However,the Cu2O mode is formed by the reaction of surplus O2 and CuCl with O2 flow rate increasing over 0.4 L/min, causing CuCl volatilization rate and copper removal rate to decrease. The resulting copper removal rate of 84.34% is obtained under the optimum conditions of holding temperature of 1573 K, residence time of 10 min, Ca Cl2 addition amount of 0.1(mass ratio of CaCl2 and the copper slag) and oxygen flow rate of 0.4 L/min. The efficient removal of copper from copper slags through chlorination is feasible.

Green leaching and predictive model for copper recovery from waste smelting slag with choline chloride-based deep eutectic solvent

This research was performed to investigate the optimization of copper recovery from copper smelting slag(CSS)with a deep eutectic solvent as a green reagent.The effect of important parameters on the leaching efficiency of copper and zinc(as well as dissolution of iron),such as leaching time,leaching temperature,solid/liquid ratio,and particle size was studied.In order to model the copper recovery,an optimization method was used.According to the chemical analysis of CSS,the slag contains 0.9%copper,3.3%zinc,and 36.7%iron.Also,it was found that the CSS is mainly composed of Fe2SiO4,Fe3O4 and SiO2.Copper-containing structures were determined as CuO and CuS.As a result of leaching experiments,80%copper and 61%zinc recoveries were obtained at 48 h,95℃,1/25 g·ml^(-1),and-33 mm.It is noted that the iron and silicon dissolution remained negligible under the selected conditions.According to the mathematical model,the highest copper leaching efficiency(up to 100%)could be under optimum working conditions as 48.5℃leaching temperature,40.1 h leaching duration,and 62.3 ml·g^(-1)solid/liquid ratio.Also,the proposed model revealed that a wide range of experimental levels can be used as leaching parameter to get desired metal leaching efficiency.