Decomposition Kinetics of Magnesium Oxychloride Phases

The decomposition characteristics of four magnesium oxychloride phases in the system MgO—MgCl2–H2O were studied by the thermogravimetric method. The decomposition rate curves obtained at different temperatures in the interval 100°–500°C were found to follow formal first order kinetics. The activation energy values of the decomposition reactions were calculated to compare the thermal stabilities of the phases. The 5-phase was suggested as the desirable one in magnesium oxychloride cement for high temperature application as refractory castables.