Kinetic study of non-isothermal decomposition of a composite diasporic-boehmitic bauxite

In the current study, the kinetic of the thermal decomposition of a composite diasporic-boehmitic bauxite is investigated under non-isothermal heating conditions by means of thermogravimetric analysis. The calculation of activation energy (Ea) has been performed by various methods and the attained values range from 185000 to 190000 J.mol-1 for conversion rate of 0.5. The first-order kinetic model can adequately be used to describe thermal decomposition of bauxite composite, while the pre-exponential factor value was found to be 2.088*1011 min-1. The calculated activation energy value together with pre-exponential factor and the solid state kinetic model factors enable the simulation of the thermal decomposition under various heating conditions by the implementation of an ordinary differential equation. The calculated values are in satisfactory agreement with the experimental ones.