A method for the production of uranium oxide, compositions of uranium hexafluoride

摘要

1426159 Uranium dioxide compositions GENERAL ELECTRIC CO 14 May 1974 [10 Aug 1973] 21385/74 Heading C1A A uranium dioxide-rich composition is prepared from uranium hexafluoride in a reaction zone in the presence of an active flame by: (a) introducing into the rection zone a gaseous mixture of uranium hexafluoride and a reducing carrier gas (b) separately introducing an oxygencontaining gas and (c) separately introducing between (a) and (b), a shielding gas which temporarily prevents substantial mixing and reaction between (a) and (b) until sufficient cross diffusion of (a) and (b) with the shielding gas occurs as they pass through the reaction zone. The reaction may be initiated by introducing (a) reducing carrier gas (b) shielding gas (c) oxygen-containing gas and (d) uranium hexafluoride in sequential steps into the reaction zone (optionally the reducing carrier gas and uranium hexafluoride may be introduced simultaneously). The reaction may also be initiated by introducing (a) oxygen-containing gas (b) shielding gas (c) reducing carrier gas and (d) uranium hexafluoride in sequential steps into the reaction zone. The reaction zone may be purged with inert gas before the gaseous reactants are introduced. The mixture of uranium hexafluoride and reducing carrier gas may be introduced into the reaction zone as a plurality of individual adjacent streams each surrounded by shielding gas. The reducing carrier gas may be hydrogen, dissociated ammonia or a mixture thereof or the above mixed with an inert gas. The oxygen-containing gas may be oxygen, air or a mixture thereof. The shielding gas may be hydrogen, dissociated ammonia, an inert gas or a mixture thereof. The molar ratio of the reducing carrier gas to uranium hexafluoride may be at least 4À0 and that of oxygen to uranium hexafluoride at least 1À2. The reaction may occur in a flame of at least 750‹ C. The reaction zone may be preheated to at least 100‹ C. The reaction zone may be maintained under a reduced pressure of 1-25 inches of mercury to draw the reaction products from the reaction gas and the gas stream withdrawn may be treated to collect hydrogen fluoride and water vapour in the form of hydrofluoric acid. The uranium dioxide formed by the above method may be converted to a higher oxide of uranium by converting the residual reducing gas in the reaction zone into an oxidized form.