Dynamic chromatographic systems for the determination of rare earths and thorium in samples from uranium ore refining processes

Dynamic ion exchange has been used for the rapid separation (16 min) and determination of rare earths and Y in samples from hydrometallurgical processes used to recover, U, Th, Y, and the rare earths from uranium ore. Optimization of the effective capacity of the dynamic ion exchanger and the selectivity of postcolumn reaction detection permitted analysis down to 0.1 ..mu..g-mL/sup -1/ of the rare earths and yttrium in the presence of U, Th, and a number of other metal ions. A comparison with X-ray fluorescence results showed good agreement, and the chromatographic procedure offered considerable savings in analysis time. Studies with Th(IV) and U(VI) showed that both metal ions exhibited selective sorption of their ..cap alpha..-hydroxyisobutyric complexes, formed in situ in the eluent, onto reversed phases. The analytical results obtained showed that this dynamic separation process could be used for the determination of Th, and its potential for the determination of U was demonstrated.