Phase diagrams and thermodynamic modeling of solid-liquid equilibria in the system NaCl–KCl–SrCl2–H2O and its application in industry. (September 2019)

• Record Type: Journal Article
• Authors: Li, Dan; Liu, Yuanhui; Meng, Lingzong; Guo, Yafei; Deng, Tianlong; Yang, Lan
• Is Part Of: Journal of chemical thermodynamics. Volume 136(2019)
• Page Start: 1
• Page End: 7
• Publication Date: 2019-09
• Subjects: Pitzer thermodynamic model -- Solid–liquid phase equilibrium -- Strontium chloride -- Computer simulation of brine separation -- Brine system; Thermodynamics -- Periodicals; Thermochemistry -- Periodicals; Thermodynamique -- Périodiques; Thermochimie -- Périodiques; Thermochemistry; Thermodynamics; Periodicals; 541.369
• DOI: 10.1016/j.jct.2019.04.013
• Languages: English
• ISSNs: 0021-9614

Abstract

Graphical abstract: Highlights: The Pitzer thermodynamic model for the system NaCl–KCl–SrCl2 –H2 O was constructed. The thermodynamic properties in the system were calculated with the Pitzer model. The phase diagram and Pitzer model were used for simulation of brine separation. Abstract: Combining of the determined solubilities of two ternary systems NaCl–SrCl2 –H2 O and KCl–SrCl2 –H2 O and Pitzer binary parameters obtained in the literature at different temperatures, the lacking Pitzer mixing parameters θ Na, Sr, θ K, Sr, Ψ Na, Sr, Cl, and Ψ K, Sr, Cl were fitted on the basis of the Pitzer model. The variable temperature chemical model for Pitzer mixing parameters including Sr 2+ ion was built. The model was then used to calculate thermodynamic properties such as the solubilities, osmotic coefficients, ionic activity coefficients and dilution enthalpy of the quaternary system NaCl–KCl–SrCl2 –H2 O in the wider temperature range. The theoretical results using the model coincide with the experimental values. The phase diagrams and Pitzer model for the quaternary system were then used to conduct computer simulation of isothermal evaporation and brine separation. The evaporation-crystallization route and the order of salt crystallization were obtained using the model at 298.15 K. The pure salts KCl, NaCl and SrCl2 ·6H2 O were separated from the solution with the model at 273.15 K and 323.15 K.