INFLUENCE OF ZIRCONIUM AND NIOBIUM ON CATHODIC DEPOSITION OF URANIUM-DIOXIDE FROM ALKALI CHLORIDE MELTS

Electrocrystallization of uranium dioxide from molten chloride electro lytes in the presence of zirconium(IV) and niobium(V) was studied by v oltammetry. Zirconium(IV) was found to react with uranium dioxide acco rding to exchange mechanism to form (1 - x) UO2 . xZrO(2) solid soluti ons. Niobium(IV), a product of cathodic reduction of niobium(V), enter s into the exchange reaction with uranium dioxide to yield (1-y) UO2 . yNbO(2) solid solutions. In the case of simultaneous presence of Nb(V ) and Zr(IV) in electrolyte, ternary (1-x-y) UO2 . xZrO(2) . yNbO(2) s olid solutions are obtained at the cathode surface. Nucleation of the solid solutions phase was shown to occurs at the most active sites of the crystalline precipitate of uranium dioxide.