Experimental and modeling vapor-liquid equilibria: Separation of Bi from Sn by vacuum distillation

The vapor-liquid equilibria (VLE) for SnBi binary alloy at 5 Pa were carried out at distillation temperatures in the range of 1150 K-1550 K under vacuum condition. The experimental results indicate that Bi can be satisfactorily removed from crude Sn, the content of tin in liquid phase reaching more than 99.99 wt% at a temperature higher than 1300 K. The thermodynamic consistency of the experimental data was checked by Van Ness method. The Wilson equation is used to predicate VLE data. The results show good agreement with the experimental data, indicating that VLE phase diagram is feasible and practical for the process of vacuum distillation of alloys.