Experimental study and thermodynamic optimization of the CaO-NiO, MgO-NiO and NiO-SiO2 systems

► Thermodynamic optimization of the CaO-NiO, MgO-NiO and NiO-SiO2 systems. ► Phase equilibria studied by equilibration, quenching and EPMA. ► A set of self-consistent Gibbs energy functions of all phases was obtained. ► All phase equilibrium and thermodynamic data are reproduced within experimental error limits. ► This is the basis for a thermodynamic database for simulation of nickel extraction from ores.