Study on Impurity Separation and Purification of Scandium Metal by Vacuum Distillation AITranslate

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Chinese Library Classification Number:TF845.1[冶金工程—有色金属冶金]

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By thermodynamic calculation using Miedema mixing enthalpy model,the saturated vapor pressure of each element in scandium metal,the separation coefficient of impurity elements from Sc,and the distillation volatilization rate were obtained.The separation characteristics and rules of Fe and Al impurities in the process of scandium metal purification by vacuum distillation were analyzed.According to the results of theoretical analysis,the vacuum distillation and purification experiment of scandium metal was carried out under the conditions of distillation temperature of 1550~1700℃and vacuum degree less than 10^-3Pa.The calculation results show that the saturated vapor pressure difference between the impurities Mg,Ca,Mn,and Ni and the main element Sc is large,and they are easy to separate by vacuum distillation,while Fe and Al impurities with saturated vapor pressure close to Sc are difficult to separate.The separation coefficient of Al and Fe impurities from Sc at 1550~1700℃is far less than 1 and gradually increases with the increase of distillation temperature,which is not conducive to the separation of Sc from Fe and Al.With the increase of distillation temperature,the volatilization rate of Sc and impurity Fe and Al gradually increases,and the volatilization rate of the impurities further increases with the increase of their content.The experimental results show that vacuum distillation can effectively remove Fe and Al impurities in scandium metal,so that they remain in the slag phase.