Vacuum Distillation Separation Of Zinc Pewter

As the traditional predominate resource, zinc, lead and tin are widely used in many industry .Along with the shrink of geologic reconnaissance, the rapid improvement of exploitation degree and smelting capability, the crisis of non-ferrous metals resource has come out. The advantage of non-ferrous industry, such as abundance resource and enough raw material supply, has changed thoroughly. The available resource and supply capacity of mine has become inconsistent with the growth speed of non-ferrous industry. In order to alleviate the shortage of resource, the regeneration of metals shows more importance.In this paper, we are using vacuum distillation to regenerate metals from zinc-lead-tin alloy. By this way, it has some advantages such as short flow, low cost and easy operation. It may be a new method for the regeneration of the alloy.Studies on the feasibility of separating alloy by vacuum distillation have been carried out. According to the difference of boiling point, saturation vapor pressure of element and the separation coefficient β of zinc-based alloy , we can say the separation is easy from the thermodynamic analysis. Then the kinetics study is carried out. The four process of distillation and the influence factors of evaporation are discussed. The kinetics studies show that in order to increase the productivity of equipments and decrease cost and enhance economic efficiency, a suitable temperature and remained pressure is needed when vacuum distillation is carried out.According to the analysis of vacuum distillation, the experiment is carried out in an inner-heated vacuum furnace. The influence of time, temperature and remained pressure on separation effect is discussed. The experiment shows that the optimal conditions are 820°C, 60min and 15Pa in furnace.Based on this, the industrial experiment is carried out in horizontal vacuumfurnace. The optimal conditions are 900°C, 8h and 40Pa in furnace when the disposal capability is 1200kg per furnace. On this condition, we can obtain good recovery ratio of raw materials. The zinc content is over 99.9%, tin content is under 0.002%, lead content is under 0.001% in zinc metal. In lead-tin alloy, zinc content is under 3.9%, tin content is over 85%.