1.Frumkin Institute of Physical Chemistry and Electrochemistry,Russian Academy of Sciences,Moscow,Russia
Abstract:
Decomposition of aqueous suspensions of uranium(IV) oxalate under the action of an ozone–oxygen mixture was studied. The process occurs in two steps. In the first step, the U(IV) oxidation with the formation of oxalic acid uranyl solutions prevails. The second step involves decomposition of oxalate ions and hydrolysis of uranyl ions. An increase in temperature accelerates the transformation of uranium(IV) oxalate into uranium(VI) hydroxide compounds. In solutions containing KBr or UO2Br2, the following reaction occurs: O3 + Br– → O2 + BrO–. The arising hypobromite ions and hypobromous acid oxidize uranium(IV) oxalate extremely efficiently. The possible mechanism of ozonation of aqueous uranium(IV) oxalate suspensions is discussed.