A Clean and Efficient Method for Recovering Copper and Tin from Waste Tin-Coated Copper Wire by Partial Sulfuration - Vacuum Distillation

Abstract

Waste tin-coated copper wire is the copper-tin waste produced when new products replace old products in the electronic and electrical fields. At present, the existing technology for separating and recovering copper-tin waste has many problems, such as low tin removal and environmental pollution caused by waste liquid. The partial sulfurization-vacuum distillation process has been developed to treat waste tin-coated copper in response to existing process issues. Using sulfur as the sulfurizing reagent, the sulfur vapor reacts with the tin on the surface of the waste tin-coated copper wires in a closed environment to form stannous sulfide, which is volatilized under vacuum and high temperature to achieve the removal of tin from the waste tin-coated copper wires. Under the optimal conditions of partial 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 97.54%, and the copper recovery rate is 99.7%. This method recovers copper and tin elements from waste tin-coated copper wire in the form of copper metal elemental and high-purity stannous sulfide, respectively.

Keywords: Waste tin-coated copper wire, Partial sulfuration, Vacuum distillation, High efficiency separation, Metal recovery