<Original Papers>Reduction Equilibria of Iron Oxides. (I) : Measurement of Equilibrium of the Reaction, Fe_3O_4 (in wustit)+CO=3FeO (in wustit)+CO_2

The equilibrium of the following reaction was measured, with flow method at 700-1200℃, [chemical formula] According to the experiments, wustit cannot be accepted as an ideal solid solution. The relation between % of O_2 in wustit and % of CO in gas at a definite tomperature was expressed by the following empirical formula, [chemical formula] where N_ and N_ were the mol. fractions of FeO and Fe_3O_4 in wustit respectively, a and b were constants. Consequently, denoting the activities of FeO and Fe_3O_4,by a_ and α_, the activity coefficients of FeO and Fe_3O_4,by γ_ and γ_ respectively, and taking γ_ and γ_ equal to unity for a standard state, where N_ is in infinite dilution and the activities concide with molar fraction, the equilibrium constant K and the temperature function of Log K were given in the following equations (3) and (4). [chemical formula] The equilibrium relation between wustit and H_2-H_2O mixed gas was calculated from equation (3) and the equilibrium constant of water-gas reaction ; the temperature function of Log K was calculated as follows : [chemical formula] Furthermore, as the temperature function of dissociation constant of wustit, the following equation was obtained from equation (3) and the dissociation constant of CO_2 : [chemical formula