Process optimization for vacuum distillation of Sn–Sb alloy by response surface methodology

Abstract

Based on the molecular interaction volume model (MIVM), the vapor–liquid phase equilibrium of Sn–Sb alloy was calculated, which was used to predict the element distribution of Sn–Sb alloy between vapor and liquid phase during vacuum distillation. A central composite design (CCD) was used to optimize the process parameters influencing the content of Sn in liquid phase and the direct yield of Sn. The studied parameters were distillation temperature, feeding materials and soaking time. Two quadratic mathematical model equations were derived for predicting the content of Sn in liquid phase and the direct yield of Sn. The analysis of variance (ANOVA) shown that distillation temperature was the most significant factor affecting the separation of Sn–Sb alloy. In the process optimization, while the direct yield of Sn equal to 92%, the maximum content of Sn in liquid phase should be 99.66 wt.% under the conditions of 1531 K, 137 g and 46 min. The confirmation test values of 91.22% and 99.43 wt.% were fair agreement with the predicted data, which demonstrated that these models were very good and can be used for parameter optimization in vacuum distillation.