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Separation of thorium and rare earth salts by solvent extraction

Journal Article · · J. Phys. Colloid Chem.; (United States)
DOI:https://doi.org/10.1021/j150479a006· OSTI ID:5869758

Rare earth chlorides are extracted very slightly from aqueous solutions by 1-butanol and no separation is feasible under these conditions. Rare earth and thorium nitrates are extracted to a significant extent from aqueous solutions by 1-butanol. The order of decreasing extractability is given by neodymium through ytterbium and then thorium. Rare earths are extracted to a reasonable extent by 1-pentanol from aqueous solutions containing ammonium thiocyanate. Thorium is so much more extractable than any of the rare earths that a simple, very effective means of separating thorium from the rare earths is thereby afforded. Cerium usually present in natural thorium ores must be reduced to the trivalent state prior to the addition of thiocyanate. The more basic rare earths are the most difficult to separate from thorium in the preceding process. Single-step extractions of synthetic neodymium-thorium mixtures were carried out at two fixed thiocyanate concentrations and very good separations were obtained. No marked difference in selectivity for one thiocyanate concentration over the other was found to exist. The equilibrium distribution of thorium between water and 1-pentanol is influenced by the presence of neodymium and vice versa. Therefore, distribution curves for the pure materials cannot be used to predict accurately the behavior of mixtures, although they may be used as first approximations.

OSTI ID:
5869758
Journal Information:
J. Phys. Colloid Chem.; (United States), Journal Name: J. Phys. Colloid Chem.; (United States) Vol. 54; ISSN JPCCA
Country of Publication:
United States
Language:
English