Determination of the phase boundaries of the wustite solid solution within the context of reduction tests

Oxygen reduction measurements performed isothermally on Fe 2 O 3 with CO/CO 2 gas mixtures make it possible, in combination with a system of equations describing the homogeneous wustite phase FeO n , to describe also the boundaries of this solid solution mathematically. Compared with corresponding data determined by Giddings and Gordon on the basis of a literature evaluation, the boundaries of the wustite field are found to shift to a much lower reduction potential. The developed system of equations makes it possible to plot the curves of the same oxygen concentration in the homogeneous wustite phase field of the Bauer-Glaessner diagram. When comparing the reduction equilibria of the left- and right-hand wustite solid solution boundary with the appropriate literature data there is a good agreement particularly with the measurements of Darken and Gurry