Effect of Particle Size on the Kinetics of the Reaction Between Magnesium and Aluminum Oxides

The kinetics of the reaction MgO+A1 2O3 +MgAl 2O4 was studied using both unsized “small” (∼1 to 3 pm) and sized “large” (∼50 and 100 μm) particles of the reactants within narrow size distributions and uniform shapes. The data were fitted to various equations commonly used in kinetic analyses of isothermal reactions of solids, analyzed by graphical analysis and linear regression analysis, and compared in terms of the predictive mean square error (MSE) criterion. Graphical and linear regression analysis showed that the reaction could be described almost equally well by first‐order kinetics, the equation derived by Avrami‐Erofe'ev for the nucleation and growth model, and the equations of Jander, Carter, and Ginstling‐Brounshtein for diffusion models. The MSE method gave similar results, except that the model of Avrami‐Erofe'ev was marginally better than the other four equations. The results are compared with those of the systems BaC O3 +Fe 2O3 and MgO+Fe 2O3 studied previously.