Electrolytic Uranium Dioxide from Uranyl Halides

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Fused salt electrolysis obtaining uranium dioxide has been demonstrated to be applicable to uranyl fluoride resulting from the hydrolysis of uranium hexafluoride. The potential-pO^2- (negative logarithm of the activity of O^2- ion) diagram was referred for guidance in electrowinning of UO₂ from fused halides. Acceptors of O^2- ion were found to produce good melts with sufficient dryness for obtaining sound UO₂. Polarograms of uranyl reduction showed that uranium oxide would exist in the form of UO₂ as an intermediate species at low concentrations of UO₂(VI). Carbon anodes in molten solution containing UO₂(VI) would act as UO₂ electrodes prior to the electrolysis, so that low cell voltages such as 0.05V were sufficient at low current densities. Crystalline UO₂ particles produced in an electrolytic pilot unit with a capacity of 1kg oxide had a density of up to 10.75g/cm³ and total impurities were less than 0.1%.