Experimental investigation and calculation of vapor–liquid equilibria for Cu–Pb binary alloy in vacuum distillation

• Vacuum distillation experiments of high-lead crude copper were performed.
• The calculation method of vapor–liquid equilibrium (VLE) in vacuum distillation is proposed.
• Experimental results were successfully correlated with the Wilson equation.

In this study, vacuum distillation experiments of high-lead crude copper were performed under the vapor pressure 5 Pa. The content of lead in crude copper was reduced from 15% to less than 0.01% in a single stage distillation process with residual vapor pressures of below 10 Pa, distillation temperatures of 1423 K and distillation times of 60 min. The vapor–liquid equilibrium (VLE) phase diagrams of Cu–Pb binary alloy in vacuum distillation were calculated using the Wilson equation. Thermodynamic experimental data taken from literature were used for calculating Wilson equation temperature dependent interaction parameters. The calculations give a satisfactory accuracy with the experimental data for separation of Cu–Pb alloy in vacuum distillation. The results indicate that VLE phase diagrams under vacuum obtained by this method are reliable for predicting the process of vacuum distillation for Cu–Pb alloy. The VLE phase diagrams of alloys will have significant benefits for the industrial production of vacuum metallurgy especially for the process of multistage distillation in the vacuum furnace.