Kinetic studies on the oxidation of uranium(IV) in nitric acid solution

The kinetics of oxidation of U(IV) in nitric acid solution by nitrous acid and air oxygen have been studied. The effects of concentrations of U(IV), nitric acid, hydrogen ion and nitrous acid in aqueous solution or oxygen in gas on the oxidation rate have been examined. The oxidation rate increases with increasing temperature and the activation energies are 47 kJ mol^–1 for nitrous acid and 91 kJ mol^–1 for oxygen. The mechanisms for both oxidation reactions are discussed.