Phase Equilibrium Diagram CaO—CaF 2 —2CaO.SiO 2

Differential thermal analysis and quenching experiments were used to establish the ternary phase diagram CaO‐CaF 2 ‐2CaO.SiO 2 . Hermetically‐closed platinum capsules were used to prevent fluorine loss in the form of HF, SiF 4 , and CaF 2 by reaction of the CaF 2 with water vapor or SiO 2 , or by evaporation. The melting point of pure CaF 2 was 1419°± 1°C. There is one binary eutectic in the system CaO‐CaF 2 and there are two ternary eutectics in the system CaO‐CaF 2 ‐2CaO.SiO 2 . The results of the present study were combined with literature data to construct the phase diagram CaO‐CaF 2 ‐SiO 2 .