Separation of rare earths by an ion-exchange method

Establishment of a generalized method of separating and analyzing trace impurities of high-purity rare earth oxides was attempted by neutron irradiation. The amount of the target materials and the size of the ion-exchange columns used for the analysis were made uniform. The element with atomic number lower by one was added to the irradiated target solution, prior to the cation-exchange separation, in an amount comparable to that of the carrier. α-Hydroxyisobutyrate solutions of various concentrations were used as eluent, the pH value always being kept constant at 3. 77. By this method, impurities of Gd, Dy, Ho and Er in Tb₄O₇, Dy, Er and Yb in Ho₂O₃, and Sc, Eu, Tb and Tm in Yb₂O₃ were determined.