A thermodynamic model of aqueous electrolyte solution behavior and solid-liquid equilibrium in the Li-H-Na-K-Cl-OH-H2O system to very high concentrations (40 molal) and from 0 to 250  C

Abstract

This paper describes a chemical model that calculates solute and solvent activities and solid-liquid equilibria in the Li-H-Na-K-Cl-OH-H 2 O system from dilute to high solution concentration within the 0 to 250°C temperature range. The model coherently extends to Li the temperature-variable H-Na-K-OH-Cl-H 2 O model of Christov and Møller (2004b, p. 1309). The solubility modeling approach based on Pitzer's (1973, p. 268) specific interaction equations is used. All binary (LiCl-H 2 O and LiOH-H 2 O) and ternary (LiCl-HCl-H 2 O, LiCl-NaCl-H 2 O, LiCl-KCl-H 2 O, LiOH-NaOH-H 2 O, LiOH-KOH-H 2 O, and LiOH-LiCl-H 2 O) lithium subsystems are included in the model parameterization. The model for the LiCl-H 2 O system is parameterized using two different approaches: (1) with 4 ion interaction binary parameters (␤ (0) , ␤ (1) , ␤ (2) , and C ), and (2) with 3 ion interaction binary parameters (␤ (0) , ␤ (1) , and C ) and including neutral aqueous LiCl 0 (aq) species. Approach (2) provides a better fit of activity data in unsaturated binary solutions and accurately predicts solid solubilities up to 40 mol.kg ؊1 and up to 250°C. Therefore, this approach was used to parameterize lithium chloride mixed systems. Temperature functions for the thermodynamic solubility product (as log K o sp ) of 5 simple lithium salts (LiCl.2H 2 O(cr), LiCl. H 2 O(cr), LiCl(cr), LiOH. H 2 O(cr), and LiOH(cr)) are determined. The log K o sp values of 3 double lithium basic salts precipitating in the LiOH-LiCl-H 2 O system at 50°C (3LiOH. LiCl(cr), LiOH.LiCl(cr), and LiOH.3LiCl(cr)) are also estimated using solubility data.

A New Pitzer Parameterization for the Binary NaOH–H2O and Ternary NaOH–NaCl–H2O and NaOH–LiOH–H2O Systems up to NaOH Solid Salt Saturation, from 273.15 to 523.15 K and at Saturated Vapor Pressure

“…This system was studied by Lassin et al [28] using the interaction parameters provided by Christov and Møller [16] for the NaOH-H 2 O system. Because of the concentration limits of this set of parameters, we reconsidered the system and used the NaOH parameterization determined in this study.…”

“…Indeed, rather than high order virial coefficients, Pitzer and Silvester [24] introduced a neutral species that comes from the partial dissociation of phosphoric acid. Later, several authors successfully included the HPO 4 0 (aq) species [25][26][27] to describe the behavior of the phosphoric acid system up to 24 molÁkg -1 using either the original Pitzer's model or the modified Pitzer's model [28]. In our model for NaOH-H 2 O at high temperature and high salinity, it was necessary to introduce the neutral species NaOH 0 (aq).…”

“…Because of the concentration limits of this set of parameters, we reconsidered the system and used the NaOH parameterization determined in this study. The interaction parameters of the binary system LiOH-H 2 O come from Lassin et al [28] who considered dissolved LiOH to be completely dissociated (additional data are given in Electronic Supplementary Material). Few experimental data exist on this system [41,62] and these authors published inconsistent values.…”

Thermodynamic model for solution behavior and solid-liquid equilibrium in Na-Al(III)-Fe(III)-Cr(III)-Cl-H2O system at 25°C

“…The system Na-Al(III)-Cr(III)-Fe(III)-Cl-H2O have been investigated according to the following scheme [5,8,9,19] evaluation of not-concentration restricted (β 0 , β 1 , (β 2 ) and C φ ) parameters for binary systems NaCl-H2O, AlCl3-H2O, FeCl3-H2O, and CrCl3-H2O, and determination of the chemical potential of solids precipitating from saturated binary solutions; determination of mixing parameters, i.e. evaluation of the following parameters: A) θ(Na,Al), and ψ(Na,Al,Cl) for ternary system NaCl-AlCl3-H2O; B) θ(Na,Fe), and ψ(Na,Fe,Cl) for ternary system NaCl-FeCl3-H2O; C) θ(Na,Cr), and ψ(Na,Cr,Cl) for ternary system NaCl-CrCl3-H2O; D) θ(Al,Fe), and ψ(Al,Fe,Cl) for ternary system AlCl3-FeCl3-H2O; E) θ(Al,Cr), and ψ(Al,Cr,Cl) for ternary system AlCl3-CrCl3-H2O, and F) θ (Cr,Fe), and ψ(Cr,Fe,Cl) for ternary system CrCl3-FeCl3-H2O.…”

“…The specific interaction approach for describing electrolyte solutions to high concentration introduced by Pitzer [1,2] represents a significant advance in physical chemistry that has facilitated the construction of accurate thermodynamic models. It was showed that the Pitzer approach could be expanded to accurately calculate solubilities in complex brines and to predict the behavior of natural fluids at standard temeperature [3][4][5], as well as at wide range of temperatures from 0 o to 300 o C [6][7][8][9] , and from extremely low [10][11][12] to very high concentration of solutions [8,9,35]. However, the existing Pitzer's databases have different limitations as the number of implemented solution species and precipitating solids, the temperature and concentration ranges of application.…”