The Activity Of Cao In The Cao-Cacl2 And Cao-Cacl2-Caf2 Systems

To clarify the refining ability of the CaO-CaCl2-CaF2 systems and the effect of replacement of CaF2 with CaCl2 on the CaO activity, the activities of CaO in the CaO-CaCl2 and CaO-CaCl2-CaF2 systems were measured at 1 673 K by employing a chemical equilibration technique. The activity of CaO relative to liquid CaO in the CaO-CaCl2 system was observed to have negative deviation from ideal behavior with the solubility of CaO being X(CaO)=0.32. The activity of CaO in the CaO-CaCl2-CaF2 system at 1 673 K decreases by replacing CaF2 with CaCl2 at constant CaO content. The refining ability of the CaO-CaCl2-CaF2 fluxes is discussed.The activity coefficient of calcium in silver was found to be constant up to the calcium content of 0.625 mass%. The standard Gibbs energy of the formation of CaO was determined from 1 573 to 1 773 K.