Calculation of Distillation Refining of a Substance Containing Low and Highly Volatile Impurities

This paper considers the distillation refining of a material containing highly volatile and low-volatile impurities and demonstrates the possibility of evaluating the fraction of residue, gr, during the removal of the highly volatile impurity and the degree of subsequent distillation, gc, necessary for achieving a predetermined decrease in impurity concentrations at a predetermined product yield and known separation factors. Examples are presented for the distillation in real host–impurity systems: Ga–(Pb,Al), Be–(Al,Fe), and Cr–(Si,Fe).