Overall kinetic study of non-isothermal decomposition of calcium carbonate

Abstract

The present paper is a comparative study of six different non-isothermal methods of kinetic analysis for the determination of the mechanism of the thermal decomposition of CaCO₃ from thermogravimetric experiments. The whole experiment was carried out in a thermogravimetric analyser with nitrogen atmosphere up to 1100°C and at five different heating rates, i.e. 5, 10, 20, 30 and 40 K min^–1. Applying each of these methods, the kinetic parameters of the reaction are evaluated and an assessment is made for the kinetic model that best represents the mechanism of the decomposition. The mean value of the activation energy under continuous flow of nitrogen is E=176·3–176·4 kJ mol^–1. The value of the pre-exponential factor is ln (A_mean/s^–1)=13·7 according to model dependent methods and the phase boundary controlled reaction of cylindrical geometry is the kinetic model, which describes best the calcium carbonate decomposition.