Abstract
The heat of mixing of silica(β-cristobalite) with liquid wustite melted in an iron vessel has been directly measured at 1420°C by the modified isoperibol calorimeter(iso-thermal jacket type). Mixing of solid silica with liquid wustite is an exothermic reaction and the measured heat, ΔHFetO(l)-SiO2(β-cristobalite), is about-900cal/mol at the fayalite composition. Heats of mixing of liquid silica with liquid wustite, ΔHMFetO(l)-SiO2(l), are obtained by the combination of this direct measured results and heat of fusion of SiO2 in the reference. This result is discussed in comparison with the estimated values by the thermochemical data and by the assumption of the regular solution.
