Reversibility of Thermal Dissociation of Magnesium Carbonate in a Closed System.

The reversibility of thermal dissociation of magnesium carbonate in an evacuated sealed vial during repeated heating and cooling cycles was studied by the method of differential scanning calorimetry. It was established that the thermal effects of the dehydration and dissociation reaction decrease with an increase in the holding time above the dissociation temperature. The decrease in heat absorption is attributed to recrystallization of 'active' magnesium oxide forming at high temperatures.