Thermodynamic Modeling of the H2O–NaCl–KCl–AlCl3 System

The dew point approach is used for the first time to determine the activity of water in the H2O–NaCl–KCl–AlCl3 system at 298.15 K and in the constituent ternary subsystems at 298.15 and 323.15 K. A set of parameters for the Pitzer–Simonson–Clegg liquid phase model is proposed that adequately describes vapor–liquid equilibria, along with heat capacities of solutions and solubility in the H2O–AlCl3 system from 222.45 to 373.15 K; vapor–liquid equilibria and solubility in the H2O–NaCl–AlCl3 and H2O–KCl–AlCl3 systems in the range of 273.15 to 363.15 K, along with vapor-liquid equilibria in H2O–NaCl–KCl–AlCl3 at 298.15 K. The densities of solutions in the H2O–NaCl–KCl–AlCl3 system are measured at 298.15 K, and the resulting values are then compared to those calculated using the Laliberte model.