Kinetics of the reaction of half calcined dolomite with sulfur dioxide

Kinetics of the reaction of sulfur dioxide with half calcined dolomite were studied using gravimetric techniques. The reaction rate depends significantly on the presence of water in the reactant gas mixture. With water, the reaction is first order with respect to the sulfur dioxide concentration. Without water, the reaction rate is slower, and the reaction is 0.76 order with respect to sulfur dioxide concentration. This suggests that the rate determining step differs depending on whether or not water is present. The reaction has an apparent activation energy of 7.3 kcal/mole with water present in the reactant gas.