Kinetic analysis of non-isothermal decomposition of dolomite in nitrogen atmosphere

Abstract

In the present paper, a comparative study of five different non-isothermal kinetic analysis methods for the determination of the mechanism of the thermal decomposition of dolomite from thermogravimetric experiments, is presented. The experiments were carried out in a thermogravimetric analyser under a nitrogen atmosphere from 50 to 1100°C under non-isothermal conditions at five different heating rates, i.e. 5, 10, 20, 30 and 40 K min-1. By applying each of these methods, the kinetic parameters of the reaction were evaluated and the discrimination of the conversion function (kinetic model) that best verifies the experimental data was attempted. From a comparative study of the results of the above methods, it was concluded that the heating rate affects the activation energy values. For the model free methods, the activation energy was calculated at 242˙5 kJ mol-1 and the pre-exponential factor ln ( A, s-1 ) at 20˙6. The phase boundary reaction model of zero order was found to best represent dolomite decomposition.