CHARACTERIZATION OF THE CHEMICAL-REACTIVITY OF A CACO3 POWDER FOR ITSDECOMPOSITION

The decomposition of calcium carbonate has been studied by isothermal and isobaric thermogravimetry at 700 degrees C, under various pressure s of carbon dioxide. The kinetic curves, which have a sigmoidal shape, have been interpreted with a model involving nucleation and growth pr ocesses based on the Mampel's model. It was supposed that nucleation o ccurs at the surface of all the particles and that growth proceeds iso tropically inward in each of them. This model allowed to characterise the chemical reactivity of several CaCO3 powders by means of the deter mination of both their specific nucleation frequency and their specifi c growth rate. (C) 1998 Elsevier Science Limited. All rights reserved.