The thermal decomposition of kaolin with high-content of the medium ordered kaolinite was studied by Effluent Gas Analysis (EGA) under non-isothermal conditions. This technique enables to distinguish two overlaying processes during the thermal decomposition of kaolin: oxidation of organic compounds and dehydroxylation. The kinetic of non-isothermal dehydroxylation of kaolinite is controlled by the rate of the third-order reaction. For the given reaction mechanism, the overall activation energy (E-A) and pre-exponential (frequency) factor (A) values are 242 kJ mol(-1) and 2.21 x 10(8) s(-1), respectively. (C) 2010 Elsevier B.V. All rights reserved.