The decomposition and sintering of calcium carbonate were examined in a combined dilatometer and mass spectrometer apparatus. Carbon dioxide from the decomposition reaction is evolved from 600-1000oC for heating rates of 1-15 K minute-1. During the decomposition reaction, an initial period of shrinkage of 2-4% was observed. Above 1100oC, a second period of shrinkage of 2-4% occurred, which is attributed to the sintering of the calcium oxide produced from the decomposition reaction. Kinetic rate parameters for the decomposition, initial stage of shrinkage, and relative density were analyzed by reaction and sintering models using integral methods of analysis. Both the decomposition and relative density were reasonably well described with an activation energy of 115-120 kJ mol-1 for the full range of conversion over a wide range of temperature. The initial stage of shrinkage was described by a diffusion mechanism with an activation energy of 225 kJ mol-1.

Keywords: Calcium Carbonate, Decomposition, Sintering, Kinetic Analysis