EXTRACTION REFINEMENT OF SCANDIUM

A possibility of exhaustive removal of minor (approximate to 1%) impur ities from scandium by extraction from nitric acid solutions with neat tributyl phosphate is examined. Impurity elements are modeled by Yb a nd Zr. Isotherms of scandium extraction are obtained at initial acidit ies X(HNO3) = 8 and 11.5 M in the presence of impurity elements, for w hich the distribution factors are determined. On the basis of these da ta, a two-cascade extraction refinement process is designed, and proce ss parameters are calculated. These parameters are presented for one o f the cascades.