The study of dissolution reaction mechanism of chromium(III) oxide particles was carried out in a stirred batch-type dissolver under the constant bulk phase conditions by using relatively small amount of $Cr_2O_3$ particles.
The dissolution reaction rate, being relatively show chemical controlled reaction, was inversely proportional to the bulk phase $KMnO_4$ concentration, which is understood as the effect of the production of the solid by-product, $MnO_2$ which take a role to block the internal pores of the particles, so that the deactivation of the active sites occurs during the reaction.
The particle structures were analysed by porosimeter, SEM, and EDAX. And the overall reaction rate was measured by taking time samples.
The following kinetic model for the oxidative dissolution of chromium(III) oxide particles was proposed through the experimental results and the model satisfactorily predicted the experimental results within the experimental error range :
$r=2.29 exp(-4050/RT) Sp (1-x) (\phi_o+\phi) [MnO_4]_o^{-0.7} [H^+]_o^{0.4}-\frac{d\phi}{dt}=k_{\phi}{\cdot}{\phi}^{1.1}$
