Phase Compatibility in the System CaO–SiO2–Al2O3–SO3–Fe2O3 and the Effect of Partial Pressure on the Phase Stability

The compatibility of phases within the CaO–SiO 2 –Al 2 O 3 –SO 3 –Fe 2 O 3 system is revisited. The influence of the SO 2 partial pressure on the formation of phases and the stability of phase assemblages is addressed by means of new experimental methods (performed under controlled atmospheres) and thermodynamic calculations. Existing data from the literature are compiled and compared with the results obtained from this work. The results obtained are linked to real clinker formulations, and practical implications are discussed.