Non-isothermal kinetics study on the thermal decomposition of brucite by thermogravimetry

Abstract

The non-isothermal decomposition kinetics of brucite under nitrogen atmosphere was studied using thermogravimetry and XRD techniques. The curves of mass loss with temperature implied that the first step of thermal decomposition took place at 300–400 °C, followed by a relatively slow process up to 600 °C. The initial decomposition temperature was significantly affected by heating rate, but it had no obvious influence on the total yield of water molecules. The apparent activation energies were calculated to be 144.29 kJ mol−1 to 148.82 kJ mol−1 in the given range of conversion, and the dependence of E on the extent of conversion indicated the existence of a consecutive process. The kinetic differential equation was established as dα/dT = (1.68 × 109/β) exp(− 1.70 × 104/T) (1 − α). The thermal decomposition could be described by first-order single reaction model for the main step, whereas it was dominated by the diffusion of water molecule at the mid-late stages.