Thermodynamics of Aqueous Mixtures of Magnesium Chloride with Sodium Chloride from 298.15 to 573.15 K. New Measurements of the Enthalpies of Mixing and of Dilution

• Published in: Journal of chemical and engineering data Vol. 42; no. 6; pp. 1101 - 1110
• Main Authors: Wang, Peiming, Oakes, Charles S, Pitzer, Kenneth S
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-11-1997
• Subjects: Chemical thermodynamics; Chemistry; Exact sciences and technology; General and physical chemistry; Mixtures; Thermodynamic properties; Water; Heat of mixing; Ternary system; Enthalpy; Activity coefficient; Theoretical study; Magnesium Chlorides; Experimental study; Ionic strength; Aqueous solution; Osmotic coefficient; Thermodynamic properties; Heat of dilution; Sodium Chlorides
• ISSN: 0021-9568; 1520-5134
• DOI: 10.1021/je970114z

Heats of mixing of NaCl(aq) with MgCl2(aq) at 373.15, 423.15, 473.15, 523.15, and 573.15 K for ionic strengths 0.5−3.8 mol·kg-1 and heats of dilution of MgCl2(aq) at 523.15 and 573.15 K for ionic strengths 0.3−4.6 mol·kg-1 have been measured at a constant pressure of 20.5 MPa. These experimental data are combined with published heat of mixing data at 298 and 373 K to provide a comprehensive Pitzer ion-interaction treatment for the thermodynamic properties of the NaCl + MgCl2 + H2O system to 573 K. The treatment includes a general equation valid to 523 K, incorporating the published equations for NaCl(aq) and MgCl2(aq), and new equations for MgCl2(aq) and the mixed system at 573 K.