Thermodynamic modeling of the CoO-SiO2 and CoO-FeO-Fe2O3-Si-O2 systems

A complete critical evaluation and thermodynamic modeling of the phase diagrams and thermodynamic properties of oxide phases in the CoO-FeO-Fe2O3-SiO2 system at I bar total pressure are presented. Optimized equations for the thermodynamic properties of all phases were obtained which reproduce all available thermodynamic and phase equilibrium data within the limits of absolute experimental accuracy from 25 degrees C to above the liquidus temperatures at all compositions and oxygen partial pressures. The database of the model parameters can be used, along with software for Gibbs energy minimization, to calculate any type of phase diagram section. Unexplored phase diagram sections and activities of CoO, FeO and SiO2 in this system of industrial importance are predicted from the thermodynamic models with the optimized parameters.