Thermodynamics of Phosphorus in CaO-CaF₂-SiO₂ and CaO-CaF₂-CaCl₂ Melts Saturated with CaO

Abstract

The phosphate capacities of CaO-CaF₂-SiO₂ melts saturated with CaO were reexamined by measuring the phosphorus partition ratio between the slag and carbon saturated iron at 1300°C, because the previous data were not compatible with their sulfide capacity values which have been recently measured. New results show a good correlation between the two capacities as the theory predicts.
The influence of replacement of CaF₂ by CaCl₂ on the phosphate capacity of the CaO saturated CaO-CaF₂ melts was also studied by equilibrating the slag and silver at 1400°C. It was confirmed that thermodynamically CaF₂ is more effective for dephosphorization than CaCl₂.