Chlorination and carbochlorination of magnesium oxide

Thermogravimetric technique and boat experiments were used to study the chlorination of MgO and its reactivity with respect to Cl(2) + air, Cl(2) + N(2), and Cl(2) + CO gas mixtures at temperatures lower than 1000 degrees C. Oxychlorination of MgO occurs at temperatures higher than that of its carbochlorination. Effects of experimental parameters such as gas flow rate, temperature, and partial pressure of the carbochlorinating gas mixture on the reaction rate were examined. At 550 degrees C, the apparent reaction orders with respect to Cl(2) + CO, Cl(2), and CO were 2.37, 1.47, and 0.89, respectively. At this temperature, the maximum reaction rate was obtained using a Cl(2) + CO gas mixture having a Cl(2)/CO molar ratio equal to about 0.6. The apparent activation energy of carbochlorination of MgO was calculated as 49 kJ/mol between 425 degrees C and 600 degrees C.