Effect of cation species on solubilities of metal chlorides in water vapor at high temperatures and pressures

A flow type apparatus was used for the measurements of the solubilities of lithium chloride and calcium chloride in water vapor from 623 to 673 K and from 6.0 to 14.0 MPa. The solubilities of both metal chlorides increase with temperatures at the constant pressure. This behavior implies that the systems form the vapor-liquid equilibria at the conditions focused in this work unlike the case of sodium chloride and potassium chloride reported previously. A correlation model was developed for the solubilities of the metal chlorides in water vapor. The ionizations and hydrations of the metal chlorides were considered in the correlation model. The solubility data for the sodium chloride, potassium chloride, lithium chloride and calcium chloride in water vapor were correlated. The correlated results are in good agreement with the experimental data. The hydration numbers of metal chlorides were obtained from the correlations. It was found that the hydration numbers for the metal chlorides with monovalent cations increase with the radii of cations. For calcium chloride, the value of the hydration number is larger than those for metal chlorides with monovalent cations. (C) 2009 Elsevier B.V. All rights reserved.