High-temperature reaction between sulphur dioxide and limestone-IV. A discussion of chemical reaction mechanisms and kinetics

A model describing the chemical kinetics of the sulphation of calcium oxide has been developed in terms of elementary chemical reaction mechanisms. The model predicts that the rate-determining reaction at low tempeatures is the disproportionation of calcium sulphite and that the rate-determining reaction at high temperatures is the direct oxidation of calcium sulphite and/or the reaction between calcium oxide and sulphur trioxide. The model is in good agreement with the limited amount of experimental measurements of initial rates of the sulphation reaction available in the literature.