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Recovery of uranium from carbonaceous radioactive waste of the UF6 production line in a uranium conversion plant: Laboratory and pilot plant studies

Sadeghi, M. H ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1016/j.hydromet.2021.105747
  3. Publisher: Elsevier B.V , 2021
  4. Abstract:
  5. Carbonaceous radioactive waste is produced by adsorption of effluent gases of UF6 production line, on a bed of charcoal. Current research was aimed at developing a process for recovery of uranium from this waste in a laboratory and at pilot scale. As a first step, leaching of uranium from carbonaceous radioactive waste was undertaken by successive steps using Al(NO3)3 and nitric acid, the former used to eliminate corrosivity of the F− ions. The stoichiometry of reaction between F− and Al3+ ions form complexes ranging from AlF2+, AlF2+ to AlF3 depending upon their molar ratio. The results showed that the increase of NO3−/U ratio increased the uranium leaching efficiency. Presence of some impurities especially silica in leach liquor caused formation of crud during solvent extraction. In order to remove such impurities, first uranium was precipitated as ammonium diuranate, and then it was dissolved in nitric acid to produce uranyl nitrate solution. This solution was purified by extraction with TBP (30 vol%) /Kerosene, followed by stripping with dilute nitric acid. The pilot scale data confirmed the results of the lab scale with minor variations. The purity of the obtained uranyl nitrate solution was acceptable for returning it as a feed to UF6 production plants. © 2021 Elsevier B.V
  6. Keywords:
  7. Aluminum compounds ; Effluents ; Fluorine compounds ; Leaching ; Nitrates ; Nitric acid ; Radioactive wastes ; Radioactivity ; Recovery ; Silica ; Solvent extraction ; Uranium ; Uranium compounds ; Carbonaceous radioactive waste ; Conversion plants ; Fluoride complexation ; Pilot scale ; Plant laboratories ; Plant study ; Production line ; Urania recovery ; Uranium conversion ; Uranyl nitrate solution ; Pilot plants
  8. Source: Hydrometallurgy ; Volume 205 , 2021 ; 0304386X (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0304386X21001961