The kinetics of the chlorination of zirconium dioxide in a static bed with carbon and chlorine

Abstract

The reaction between zirconium dioxide, carbon and chlorine has been studied in a modified Stanton thermobalance between 670° and 830°C. The reaction ZrO 2+2C+2Cl 2ZrCl 4+2CO has been shown to dominate over the temperature range studied. For 30–80% of the ZrO 2 consumed, the rate follows the kinetics expected for a reaction between a gas and a solid with the reaction interface advancing linearly with time. The variation in rate with temperature over the above range, for this region of ZrO 2 conversion, could be correlated by the Arrhenius equation, the activation energy for the overall process being 55·1 kcal/mole. The degree of conversion at which the rate departed from a linear correlation increased with increasing temperature. The rate depended on the partial pressure of the chlorine to a power of 0·64, and was independent of flowrate above 1200 cc/min. Dissociation of chlorine on the oxide surface is probable.