Fundamental thermodynamic aspects of the CaO-Al2O3-SiO2system

The most important metallurgical effects of ladle treatment of aluminium-killed steels with calcium, are associated with the modification of alumina inclusion. For the development of the deoxidation-control model for inclusions, the thermodynamic slag model, based on the Gibbs energy minimization and modelling approaches postulated from J. Hastie et al., was used to calculate component oxide activities in the system CaO–Al2O3 and part of systems 3CaO · Al2O3 – SiO2, 12 CaO · 7Al2O3 – SiO2 and CaO · Al2O3 – SiO2 at 1600°C.