Behaviors of Sn, Ti and Fe in Liquid-Liquid Extraction of Nb and Ta

抄録

The behaviors of the impurities, Sn, Ti and Fe in the liquid-liquid solvent extraction of Ta and Nb with organic solvents are very important in the production of high purity Nb and Ta. The authors investigated the behaviors of impurities mentioned above in four solvent extraction systems of Ta and Nb, namely HF-hexone, HF-HCl-hexone and HF-H₂SO₄-hexone and HF-HNO₃-hexone systems: The results obtained can be summarized as follows: (1) By measuring the distribution ratios of Sn, Ti, Fe, Ta and Nb in each extractive system, it was found that Sn, Ti and Fe can be separated sufficiently from Nb and Ta. (2) The extractabilities of Sn, Ti and Fe increase with the mineral acid concentration at a constant HF acidity. (3) At a constant high HF acidity, 12.75 N, they decrease in the following order: HF-HCl system > HF-H₂SO₄ system > HF-HNO₃ system. (4) Sn % and Ti % of the total organic extract augment with the frequency of extraction in the HF-H₂SO₄, HF-HCl and HF-HNO₃ systems. (5) The separation ef each of Sn, Ti and Fe from Ta is easier than those from Nb. (6) In the HF-mineral acid-hexone system one can obtain an extract of higher purity than that in the HF-hexone system by selecting some suitable mineral acid concentrations and moreover by utilizing an advantage of larger coextractability of Nb and Ta.