ELECTROCHEMICAL REDUCTION OF URANIUM OXIDE IN MOLTEN FLUORIDE MIXTURE

A method of producing uranium metal from its oxide by a pyrometallurgical process was examined. The present method involves electrolytic reduction of dissolved uranium oxide in a molten fluoride mixture and has the characteristic that uranium oxide is electrolyzed at a high temperature above the melting point of the metal product. The possibilities for and efficiency of electrowinning are discussed for this reduction method. Electrolysis was performed at 1200-degrees-C in two kinds of molten salts containing uranium oxide: one composition is 65 wt.% BaF2-10LiF-25UF4 as type A and the other is 45.5 wt.% BaF2-19.5CaF2-10LiF-25UF4 as type B. High purity uranium metal was electrowon in molten salts of both types A and B. The metals coalescence and current efficiency for electrolysis in molten salt B were superior to those in molten salt A. In addition, it was found that current efficiency was poor for this method, because the metal product was dissolved by the reaction 3UF4 + U --> 4UF3.