Ceramics-Silikáty 31, (1) 17 - 25 (1987)

A general mathematical model of firing a ceramic body in the dehydroxylation region allows the time development of concentration and temperature fields in the body to be calculated. The model is based on the assumption that kaolinite is a binary mixture of incompressible components, i.e. water bound in the form of OH- groups in the structure of kaolinite and anhydrous kaolinite, that dehydroxylation is a first-order chemical reaction, and that firing the body in the dehydroxylation region is a combined process of mass and heat transfer. Mass transfer is regarded as diffusion involving a chemical reaction, and heat transfer as conduction of heat with a source. Using the general model, a solution for firing a body in the form of an infinite cylinder in the dehydroxylation region is suggested.