The dehydration and decomposition bauxite mixed with alkaline compounds were investigated under dynamic and isothermal conditions. Alkaline compounds (CaO or/and Na2CO3) were added to bauxite samples in various mole fractions (0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 of CaO). To determine the effect of alkaline additives on the thermal properties of bauxite, TG, DTG and DTA techniques were used simultaneously under atmospheric conditions.