Thermal decomposition of inorganic solids with reversible nature exhibits complex behavior because of physicogeometrical constraints. Moreover, its kinetics are significantly influenced by atmospheric and self-generated gaseous products due to the contribution of reverse reactions. Therefore, for universal kinetic analysis for such reactions under various temperature(T) and atmospheric conditions, the fundamental kinetic equation as a function of T and degree of reaction must be extended to consider the effect of partial pressure of gaseous products. To extend the kinetic equation, an accommodation function to explain the changes of kinetic behavior due to the gaseous product, which is expressed as a function of the partial pressure of the gas and the equilibrium partial pressure of the reaction, is introduced. The extended kinetic equation with an accommodation function enables to analyze the kinetic behavior of the reaction universally over different T and partial pressures of the gas. In this paper, the universal kinetic approach to the thermal decomposition of solids with reversible nature, based on the extended kinetic equation, is demonstrated as exemplified by the thermal decomposition of inorganic carbonates, hydroxides, and hydrates. Furthermore, the physicochemical significance of the obtained kinetic parameters is discussed.

Keywords:thermal decomposition, inorganic solids, kinetics, effect of gaseous product, physico-geometrical kinetic modeling, intrinsic kinetic parameters
Publication Date: 2025-01-25