Kinetics of the preparation of Mn_3O_4 by decomposition of MnO_2

In order to obtain the decomposition kinetics of MnO2,its decomposition processes were investigated by TG/DTA and XRD.The kinetics equation is(T625℃)and(T≥625℃)for 4MnO2=2Mn2O3+O2↑,and its activation energy is 90.239kJ/mol.The kinetics equation is for 6Mn2O3=4Mn3O4+O2↑,and its activation energy is 204.67kJ/mol.Two reactions were controlled by the nucleation and growth.