Manganese carbonate is stable in dry air, its heating decomposition process and principle of MnCO3 is :

heated in air to 300 or 500℃, 300 after began to accelerate decomposition, decomposition of manganese oxide Mn0, at the same time, if the air is enough, manganese oxide further oxidation reaction to generate MnO. 500-500 is the best manganese carbonate decomposition temperature is relative, of course, also by air, oxygen content, conditions of the furnace。