Selective Recovery of Chromium from Precipitates Containing d Elements and Actinides: II. Effect of H2O2

The oxidation of Cr(III) hydroxides of different composition and mixed Fe(III)-Cr(III) and Ni(II)-Cr(III) hydroxides has been investigated in alkaline suspensions under the action of hydrogen peroxide. The initial rate of reaction increases with increasing of Cr(III) content in the suspension and H2O2 concentration and decreases non-monotonically with NaOH concentration increase from 0.2 to 2 M. The activation energy in 0.5 M NaOH solution is 82 kJ/mole. The consumption of oxidizing agent exceeds stoichiometry