| Vacuum distillation technology are widely used in separation and purification of metals,due to its shout flow,pollution-free,simple,high metal recovery advantages.The Traditional theory of vacuum distillation is rough to judge the degree of separation of alloys by calculating the separation factor.Recently,it is reported that the vapor-liquid equilibrium theory can be used to guide vacuum distillation operation of alloys,VLE diagrams can also be applied to predict the composition of distillation products.A further study on vapor-liquid equilibrium of alloy has a great significance to design vacuum distillation experiment and guide practical vacuum distillation process.However,the experimental VLE data of binary and ternary alloys have rarely reported.VLE data,the foundation data in vacuum distillation process,is essential in the vapor-liquid equilibrium theory research and practice.,In this Paper,based on the Vapor-Liquid Equilibrium theory,an experimental investigation about vapor-liquid equilibrium of Bi-Sn?Sb-Sn,Pb-Sn binary alloys and Bi-Sb-Sn ternary alloy system,under vacuum conditions was carried out,and the corresponding VLE data was measured.According to vapor-liquid equilibrium theory,VLE data under different temperatures were calculated and the corresponding VLE phase diagrams(T-x-y diagram)were drawn by associating with Wilson equation.At the pressure of 5?10 Pa,VLE experimental and calculated data of Tin-based binary and ternary alloys were obtained by experimental investigation and theoretical calculation.A thermodynamic consistency of experimental VLE data and calculated values were tested by Herington test and Van Ness test,respectively.The test results indicated that the experimental and calculated VLE data are essentially thermodynamic consistent.It is indicated that the experimental VLE data are accurate and reliable,can be used to investigate the vapor-liquid equilibrium of the alloys.Compared VLE experimental data with calculated values,the result indicated that experimental data are consistent with calculated values within allowed range of error.The experimental points are agreement well with the behavior of each component described by calculated T-x-y diagram when the vacuum distillation under different temperatures,which implied that VLE diagrams can describe the behavior of each component exactly in the process of vacuum distillation.The best distillation conditions of Tin-based alloys shows by VLE diagrams are consistent well with experiment and practical industrial operations.These findings confirm that Vapor-liquid equilibrium diagrams can be used to guide the vacuum distillation experiment and production. |
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