A multi-stage volatilization and condensation process for green and efficient recovery of valuable metals from High-Sb crude Sn

Abstract

Circulation of Sb in an Sn refining system strongly affects the production process. In this study, an innovative multi-stage vacuum separation process was developed and successfully applied on an industrial scale. Our results indicate that Sn–Sb alloys can be completely separated by vacuum evaporation. In this study, we used single-factor experiments to investigate the effects of distillation temperature and time on several factors, such as the Sn content in the residue, Sb content in the volatile matter, separation rate, and direct recovery rate of Sb from high-Sb crude Sn. The purity of the obtained Sn and Sb products was above 99%, and the recovery rate of the metal was above 99% under the optimal distillation conditions of 1673 K and 150 min. In addition, we suggest that Sn volatilization occurs due to the presence of SbSn intermetallic compounds. A two-stage vacuum-separation process for high-Sb crude Sn was developed for industrial production. Continuous production data showed that the direct yields of Sn and Sb were 72.99% and 71.15%, respectively. The total power consumption of this process was as low as 1086 kWh/t, which is better than the corresponding parameters of other treatment processes.

Keywords

• High-Sb crude Sn
• Vacuum separation
• Cleaner production
• Environmentally friendly