The effect of temperature on the oxychlorination of Cr2O3 and MgO using Cl2+O2 was evaluated using non-isothermal conditions. A mathematical treatment of the experimental data was performed. Results were compared with those obtained using isothermal conditions. The oxychlorination of Cr2O3 up to 650°C was characterized by an apparent activation energy ‘Ea’ of ca. 83 kJ/mol. Beyond 650°C, the reaction proceeded with an Ea of ca. 51 kJ/mol. Between 850 and 1025°C, the reaction of MgO with Cl2+O2 was strongly dependent on temperature and its Ea was equal to ca. 215 kJ/mol. The values of the apparent activation energies, found for the oxychlorination of both oxides using non-isothermal conditions, were comparable to those obtained during isothermal treatment.