THERMAL CHARACTERIZATION OF DOLOMITE: KINETIC STUDY AND EFFECT OF PROCEDURAL VARIABLES

Abstract

Dolomite decomposes via a 2-stage mechanism in an atmosphere of CO2. The first stage of the decomposition was analyzed in depth using both isothermal and rising temperature kinetics. It was found that the first stage of decomposition follows the Avrami-Erofeev A2 mechanism for the isothermal experiments. However, for the rising temperature experiment, the reaction follows the Avrami-Erofeev A4 mechanism. The energy of activation (Ea) obtained for the isothermal experiments was determined to be 424.97 kJ/mol, while the value for the rising temperature experiment was 647.20 kJ/mol. Similarly, the ln A-value for the isothermal experiments was found to be 49.22, while the ln A-value for the rising temperature experiment was 74.20. The effect of procedural variables on the thermal behavior of dolomite in a nitrogen atmosphere is investigated. The program design variables include alterations in the flow rate, heating rate, grain size, and sample size. Out of these variables, heating rate, flow rate, and grain size affect the shapes of the curves. However, the flow rate of the purge gas has no effect on the thermal behavior of dolomite.