A novel method for extracting metal Ag and Cu from high value-added secondary resources by vacuum distillation

Abstract The Cu-Ag-Sb alloy produced by oxidation refining of noble lead has a high recovery value because of its high content of Ag and Cu. Vacuum metallurgy has been successfully used in crude metal refining and secondary resource recovery because of its clean and efficient characteristics. In this paper, vacuum distillation is used to treat Cu-Ag-Sb alloy, and the saturated vapor pressure of each metal element in the Cu-Ag-Sb alloy and the Gibbs free energy (ΔG) of the possible decomposition reaction are theoretically analyzed. The effects of temperature and time on the experimental results were investigated by controlling the pressure at 10 Pa, distillation temperature in the range of 1473∼1673 K and distillation time in the range of 4∼7 h. The experimental results show that after 300 kg of Cu-Ag-Sb alloy was subjected to vacuum distillation under the optimized conditions (1573 K, 6 h, and 10 Pa), Ag and Cu were recovered as volatiles and residues, respectively, and their recovery efficiency reached 99.25% and 98.11%; Ag and Cu were effectively separated. This process provides theoretical guidance for the industrial treatment of Cu-Ag-Sb alloys with no waste gas or water, which meets the needs for cleaner production in the metallurgical industry.