Non-Isothermal Kinetic Analysis of the Dehydroxylation of Kaolinite in Dynamic Air Atmosphere

A non-isothermal kinetic analysis of kaolinite dehydroxylation was carried out using thermogravimetric analysis on powder samples with heating rates from 1 to 30 °C・min^-1 in a dynamic air atmosphere. The mechanism of the reaction, values of overall activation energy and pre-exponential factor were determined from a series of thermogravimetric experiments by the Coats- Redfern method. The results show that the dehydroxylation of kaolinite is controlled by the rate of the third-order reaction (F3) with the mean values of overall activation energy (E_A) 255 kJ・mol^-1 and pre-exponential factor (A) 25.56 × 10¹⁴ s^-1.