| Separation of zirconium and hafnium from zircon caustic frit in TBP-nitric acid system has been studied. Zirconium nitrate solution is prepared by dissolving the zircon caustic frit directly in the concentrated nitric acid. Silicic acid in the solution is removed as precipitate by the addition of fluorine ion and gelatin. Unless otherwise, the presence of a small amount of silica in the solution appears to be the source of hindering the hafnium separation from zirconium. The experimental result shows that pure zirconium (more than 99.99% Zr) is obtained at 3rd stage organic phase in the counter-current extraction process, indicating that this investigation presents very similar result to that of the previously developed method. It is, therefore, clear that the direct dissolution of caustic frit in nitric acid and the subsequent extraction with TBP is simpler and cheaper method of separating zirconium and hafnium from zircon caustic frit, while the previous method involves rather complicated process to produce suitable feed solution for TBP solvent extraction. |
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