Mechanism of thermal decomposition of magnesium hydroxide

The kinetic characteristics (the rates of decomposition J and activation energies E-a) of thermal dehydroxylation of Mg(OH)(2), reported in a number of available publications, have been analysed with the supposition of dissociative evaporation of Mg(OH)(2) in the form of MgO and H2O molecules. Despite the considerable differences in the measurement conditions, the experimental values of J and E-a have been found to be in agreement with theoretical calculations. The calculations took into account the self-cooling effect, the depressing effect of external water vapor on the decomposition rate, and partial transfer of the energy released in the condensation of MgO(g) to the reactant. The agreement between the calculated and experimental data confirms the proposed mechanism of decomposition. (C) 1998 Elsevier Science B.V.