Original paper

Description of vapour-liquid phase equilibria of the H2O-NaCl system between 100 and 900°C with a thermodynamic model based on the Mean Spherical Approximation

Thiéry, Régis; Dubessy, Jean

European Journal of Mineralogy Volume 10 Number 6 (1998), p. 1151 - 1166

50 references

published: Dec 1, 1998
manuscript accepted: Apr 9, 1998
manuscript received: Mar 18, 1998

DOI: 10.1127/ejm/10/6/1151

BibTeX file

ArtNo. ESP147051006007, Price: 29.00 €

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Abstract The Mean Spherical Approximation (MSA) of the ion-dipole mixture is used to describe the vapour-liquid equilibria of the H2O-NaCl system. Comparison with experimental data reveals that the H2ONaCl mixture cannot be solely modelled by the MSA ion-dipole model. Discrepancies have been significantly reduced by taking into account NaCl ion pair formation in vapours at all temperatures and in high-temperature liquids (T>387°C). A van der Waals interaction term must be included at lower temperatures (T<387°C) and is believed to describe effects of the solvation of ions by water molecules or short-range interactions between anions and cations. The model has been fitted in the 100-850°C temperature range, and represents experimental data with a good accuracy from dilute aqueous solutions to fused salts. This model provides insights on the effects of electrostatic interactions (ion-ion, ion-dipole, dipole-dipole) and stresses the importance of NaCl ion pair formation and other effects on the vapour-liquid equilibria of the H2O-NaCl system


H2O-NaCl systemequation of stateliquid-vapour equilibriaMean Spherical Approximation