A novel method for the efficient recovery of copper and tin from waste tin-coated copper wires by controlled sulfuration-vacuum distillation

Waste tin-coated copper wire is the copper-tin waste produced when new products replace old products in the electronic and electrical fields. The current technology for recovering copper-tin waste has issues such as low tin removal and waste liquid polluting the environment. The controlled sulfuration-vacuum distillation process for treating waste tin-coated copper wire is presented in this study. In theory, the difference in sulfuration and volatilization properties of the tin-copper-sulfur system is obtained by thermodynamic analysis. In terms of method, it realizes the complete separation of tin and copper through only two steps, and no three wastes are produced in the whole process. Thermodynamic analysis shows that under the condition of pressure of 10 Pa, stannous sulfide starts to volatilize when the temperature is higher than 941 K, and the volatilization temperature of copper is much higher than that of stannous sulfide. Under the optimal conditions of controlled sulfuration process pressure of 90000 Pa, molar ratio of sulfur to tin of 7, temperature of 823 K, holding time of 2 h, vacuum distillation process pressure of 10 Pa, temperature of 1623 K, and holding time of 3 h, the tin removal rate is 97.50 %, and the copper recovery rate is 99.70 %. • The reaction is more complete when sulfur is converted into sulfur vapor. • In the sulfuration process, tin is sulfurized, but copper is not. • The tin in waste tin-coated copper wire is converted to stannous sulfide. • The copper element in the raw material is recovered as copper metal. • The copper recovery rate was 99.70 %, and the tin removal rate was 97.50 %.