The kinetics of thermal decomposition of four synthetic alkaline earth metal carbonates (MgCO3, CaCO3, SrCO3, and BaCO3) was studied under non-isothermal conditions using thermo-gravimetry. The activation energy and the pre-exponential factor for the decomposition reactions were determined using the Agarwal and Sivasubramanium integral approximation method. A new method was developed using a Turbo-C-based computer program to evaluate the integral of the kinetic equation. It was observed that the decomposition reaction of MgCO3 and CaCO3 followed two-dimensional diffusion-controlled kinetics and the decomposition reaction of SrCO3 and BaCO3 followed a Ginstling-Brounshtein model-based diffusion-controlled kinetics.