Thermodynamic modeling of the NiO–SiO2, MgO–NiO, CaO–NiO–SiO2, MgO–NiO–SiO2, CaO–MgO–NiO and CaO–MgO–NiO–SiO2 systems

A complete literature review, critical evaluation and thermodynamic optimization of phase equilibrium and thermodynamic properties of all available oxide phases in the NiO–SiO2, MgO–NiO, CaO–NiO–SiO2, MgO–NiO–SiO2, CaO–MgO–NiO and CaO–MgO–NiO–SiO2 systems at 1 bar pressure are presented. The molten oxide phase is described by the modified quasichemical model, and the Gibbs energies of solid olivine and pyroxene solutions were modeled using the compound energy formalism. A set of optimized model parameters of all phases is obtained which reproduces all available and reliable thermodynamic and phase equilibrium data within experimental error limits from 25 °C to above the liquidus temperatures over the entire composition range. The unexplored ternaries and quaternary phase diagrams and activity of liquid phase in the CaO–MgO–NiO–SiO2 system have been predicted for the first time. The database of the model parameters can be used along with software for Gibbs energy minimization to calculate all thermodynamic properties and any phase diagram section of interest.