Study On Vacuum Distillation Of Lead - Copper Alloy

Nantokite, lead salts and other intermetallic compound are formed in crude copper, lead and anode mud refining traditional pyrometallurgical process, in addition to refining copper, lead and silver. Although the main metal has been refined, the impurities varies from metallic state into intermetallic compound. The current pyrometallurgyical process has the following characteristics, complicated operation, long time consumption, high energy consumption and low rates of resource utilization. According to big difference in saturated vapor pressure and interaction force for different metal component, fundamental research in Pb-Cu-Ag alloy is carried out in this thesis.Firstly, radial distribution function, mean square displacement, density of states and electron density difference for Pb-Cu alloy at 10 Pa and 1073,1223,1373 K were calculated by ab initio. The result indicates that the degree of order for Pb-Cu melt decreased with increasing distillation temperature at the condition of identical component and system pressure. The degree of order for Pb-Cu melt increasing when Pb content in alloy increasing, at the condition of identical distillation temperature and system pressure.Secondly, Pb-Cu-Ag ternary alloy was divided into Pb-Cu and Pb-Ag two binary alloy systems. Then activity coefficients for Pb-Cu and Pb-Ag in 1073-1473 K were predicted by MIVM. Pb-Cu and Pb-Ag activity coefficients were used to calculate separation coefficient and gas-liquid phase equilibrium composition, which decide whether Pb-Cu and Pb-Ag could be separated by vacuum distillation in thermodynamics. Fixed component volatilization rate equation, obtained component volatilization rate for Pb-Cu in 1223-1423 K and Pb-Ag in 1123-1373 K, which decide whether Pb-Cu and Pb-Ag could be separated by vacuum distillation in dynamics.Finally, the best parameters for Pb-Cu alloy vacuum distillation were obtained by researching distilling temperature and time in 15% lead Pb-Cu alloy. According to above results 5-95% lead Pb-Cu alloy were investigated by vacuum distillation. The best parameters for Pb-Ag alloy vacuum distillation were obtained by investigating distilling temperature and time in 10% lead Pb-Ag alloy. And then 2.5-10% lead Pb-Ag alloy separation were investigated by vacuum distillation. According to the results of Pb-Cu and Pb-Ag alloy separation,2.85% and 22.67% sliver Pb-Cu-Ag alloy were investigated by distilling temperature and time. At last, Pb-Cu-Ag multicomponent alloy was separated by vacuum distillation.