The effect of temperature on the oxychlorination of Cr2O3 and MgO using Cl-2+O-2 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 degrees C was characterized by an apparent activation energy 'E-a' of ca. 83 kJ/mol. Beyond 650 degrees C, the reaction proceeded with an E-a of ca, 51 kJ/mol. Between 850 and 1025 degrees C, the reaction of MgO with Cl-2+O-2 was strongly dependent on temperature and its E-a 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.