2005 年 46 巻 6 号 p. 1348-1353
Thermodynamic knowledge of metal chlorides, such as vapor pressure and activity in salt/slag, are of remarkable industrial interest, particularly in fields related to the recovery/recycle/reuse of metal materials. In this study, a new apparatus for measuring the vapor pressure of metal chlorides from molten salt/slag was designed and tested with reference compounds. The results are in a good agreement with the available literature data. Using the developed apparatus, vapor pressure measurements for a KCl–NaCl–CaCl2 system have been performed. Using the measured data the activities of components were obtained. Simultaneously, the activities of components were calculated using a thermodynamic code, Factsage 5.2 wherein the Modified Quasi-chemical Model was employed to obtain the necessary thermodynamic parameters. The both data agree reasonably well with each other. The results suggested that the KCl–NaCl system exhibits similar behavior with ideal solution; while in the KCl–CaCl2 and NaCl–CaCl2 systems there are possible interactions between CaCl2 and KCl/NaCl. For the ternary system KCl–NaCl–CaCl2, in some concentration range (mole fraction of NaCl 0.25–0.50) NaCl behaves as in an ideal solution, suggesting a larger affinity between KCl and CaCl2 than that between NaCl and CaCl2.
