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Solid–liquid phase equilibria for the two aqueous systems (LiBO2 + NaBO2 + H2O) and (LiBO2 + KBO2 + H2O) at T = 288.15 K and p = 0.1 MPa were determined using the isothermal dissolution equilibrium method. The experimental results show that the phase diagrams consist of one two-salt co-saturated invariant point, two univariant solubility isotherms, and three crystallization fields. The two systems belong to simple co-saturated type, and neither double salt nor solid solution were found. The densities change regularly as the sodium metaborate (potassium metaborate) concentration increases in solution, and reach their maximum values at the invariant point. Based on the Pitzer and its extended Harvie–Møller–Weare (HMW) model, the solubilities for the ternary systems at 288.15 K were represented, and the calculated results agree well with the experimental values. [ABSTRACT FROM AUTHOR]

Experimental studies on the metastable solubilities and the physicochemical properties including density, refractive index, conductivity, and pH values in the reciprocal quaternary system containing lithium, sodium, chloride, and sulfate at 273.15 K were determined with the method of isothermal evaporation. According to the experimental results, the dry-salt phase diagram, the water phase diagram, and the physicochemical properties versus composition were plotted. In the dry-salt phase diagram, there are three invariant points, seven solubility isotherm curves, and five crystallization fields corresponding to sodium chloride, mirabilite, lithium chloride dehydrate (LiCl·2H2O), lithium sulfate monohydrate, and a double salt (Li2SO4·3Na2SO4·12H2O). There were no solid solutions formed in the reciprocal quaternary system. The crystallizing region of mirabilite is the largest, while the region of LiCl·2H2O is the smallest with the highest concentration and a strong salting-out effect to NaCl and Li2SO4·H2O. When compared with the stable phase diagram at 273.15 K, the area of the phase region of mirabilite is enlarged significantly, while the areas of the phase regions of NaCl, Li2SO4·H2O, and Li2SO4·3Na2SO4·12H2O are decreased. The calculated values of densities and refractive index in the quaternary system with empirical equations are in good agreement with the experimental values. [ABSTRACT FROM AUTHOR]

Abstract: The solubility and the density in the aqueous ternary system (Li2SO4 +MgSO4 +H2O) at T =308.15K were determined by the isothermal evaporation. Our experimental results permitted the construction of the phase diagram and the plot of density against composition. It was found that there is one eutectic point for (Li2SO4 ·H2O+MgSO4 ·7H2O), two univariant curves, and two crystallization regions corresponding to lithium sulphate monohydrate (Li2SO4 ·H2O) and epsomite (MgSO4 ·7H2O). The system belongs to a simple co-saturated type, and neither double salts nor solid solution was found. Based on the Pitzer ion-interaction model and its extended HW models of aqueous electrolyte solution, the solubility of the ternary system at T =308.15K has been calculated. The predicted solubility agrees well with the experimental values. [Copyright &y& Elsevier]

[Display omitted] • Solubility data of the aqueous system (Li+, Na+, Mg2+//Cl−, SO 4 2−-H 2 O) at T = 273.15 K were determined. • Two kinds of double salts of Li 2 SO 4 ·3Na 2 SO 4 ·12H 2 O and LiCl·MgCl 2 ·7H 2 O were found. • The Pitzer-Harvie-Weare thermodynamic model of the quinary system was constructed. • The solubilities of the quinary system were calculated, and the calculated and experimental results are in good agreement. The solubilities of the quinary system (Li+, Na+, Mg2+//Cl−, SO 4 2−-H 2 O) at 273.15 K were investigated using the isothermal dissolution method. The diagrams of dry-salt-phase, sodium-phase and water-phase were plotted accurately. The dry-salt-phase diagram of this quinary system includes five invariant points, eleven univariant solubility curves, and seven crystallization zones all saturated with sodium chloride. Two double salts of Li 2 SO 4 ·3Na 2 SO 4 ·12H 2 O and LiCl·MgCl 2 ·7H 2 O were found, and no solid solution was formed. Pitzer model and its extended Harvie-Møller-Weare (HMW) model were used to fit the solubility equilibrium constants of LiCl·2H 2 O, Li 2 SO 4 ·H 2 O and the two double salts, and the mixing ion-interaction parameters of θ Li,Na , θ Li,Mg , ψ Li,Na,Cl , ψ Li,Mg,Cl , ψ Li,Na,SO4 and ψ Li,Mg,SO4 of this system at 273.15 K, which are not reported in the literature. In addition, the calculated solubilities of the quinary system at 273.15 K were demonstrated, and the comparison between the calculated and experimental data shows that the predicted solubilities obtained by the extended HW model are basically consistent with experimental data. [ABSTRACT FROM AUTHOR]

Metastable solubilities and physicochemical properties including density and refractive index of the aqueous ternary system (Li 2 SO 4 + K 2 SO 4 + H 2 O) at 288.15 and 323.15 K and p = 0.1 MPa were determined with the isothermal evaporation method. On the basis of experimental data, the metastable phase diagrams and the diagram of physicochemical properties versus composition in the ternary system at 288.15 and 323.15 K were plotted. In the metastable phase diagrams of this ternary system at 288.15 and 323.15 K, in all there are two invariant points, three univariant solubility curves, and three metastable crystallization regions, corresponding to lithium sulfate monohydrate (Ls, Li 2 SO 4 ·H 2 O), double salt (Db, K 2 SO 4 ·Li 2 SO 4 ) and arcanite (Ar, K 2 SO 4 ). The hydrates in this system at both temperatures belong to a hydrate type I, and the double salt (K 2 SO 4 ·Li 2 SO 4 ) belongs to incongruent at 288.15 K and congruent double salt at 308.15 K, respectively. A comparison of the metastable phase diagrams at 288.15 and 323.15 K shows that the area of Ar is decreased obviously whereas the areas of Db and Ls are increased with the increasing of temperature, and no solid solutions were found. The density and refractive index in the metastable ternary system at 288.15 and 323.15 K change regularly with the mass fraction of potassium sulfate concentration and reach the extreme values at the invariant points. The densities and refractive indices were correlated with empirical equations, and the calculated values at two temperatures agree well with the experimental results. [ABSTRACT FROM AUTHOR]

Themetastable equilibrium solubilities and the physicochemicalproperties including refractive index, density, viscosity, conductivity,and pH for the aqueous reciprocal five-component system (Li + Na +K + Cl + SO4+ H2O) at 308.15 K were studiedusing the isothermal evaporation method. According to the experimentaldata, the dry-salt-phase diagram, sodium-phase diagram, water-phasediagram, and the diagrams of physicochemical properties versus compositionwere plotted. The dry-salt-phase diagram of the five-component systemincludes seven four-salt cosaturated points, fourteen univariant solubilitycurves, and eight crystallization zones all saturated with sodiumchloride. Three kinds of double salts of lithium salts (Db1, Li2SO4·3Na2SO4·12H2O; Db2, Li2SO4·Na2SO4; Db3, 2Li2SO4·Na2SO4·K2SO4) were found, and no solidsolution was formed in the metastable five-component system. Becausethe Pitzer mixing ion-interaction parameters containing lithium andsodium such as θLi,Na, ΨLi,Na,Cl, and ΨLi,Na,SO4at 308.15 K are scarce,the solubilities of the five-component system at 298.15 K were calculatedon the basis of Pitzer’s ion-interaction theory and the chemicalequilibrium Harvie–Møller–Weare model (HMW model).A comparison of the calculated phase diagram at 298.15 K and the experimentalphase diagram at 308.15 K was also carried out. [ABSTRACT FROM AUTHOR]

Thesolubility and density of the thermodynamic phase equilibriaternary system (Na2SO4+ Li2SO4+ H2O) at (288 and 308) K were determined usingthe isothermal dissolution method. According to the experimental resultsof the ternary system at (288 and 308) K, the phase diagrams and thediagrams of density versus composition were plotted. In the ternarysystem at 308 K, four crystallization regions corresponding to thenardite(Na2SO4, Th), two congruent double salts ofLi2SO4·3Na2SO4·12H2O (Db1) and Li2SO4·Na2SO4(Db2), and lithium sulfate monohydrate (Li2SO4·H2O, Ls) were found, whereas onlythree crystallization regions corresponding to Ls, one incongruentdouble salt of Db1, and mirabilite (Na2SO4·10H2O, Mir) were found in the system at 288 K. No solid solutionwas found at either temperature. When the experimental phase diagramat 308 K was compared with that at 288 K, it shows that (1) a newphase region of double salt Db2 was formed and the mineral of Mirtransformed into Th with the increase of temperature from (288 to308) K and (2) the area of the crystallization region of sodium sulfatewas decreased sharply and those of the crystallized regions of Li2SO4·H2O and double salt Db1 increasedobviously. The solution densities of the ternary system both at (288and 308) K change regularly with increasing lithium sulfate concentrationin solution. Based on the Pitzer model and its extended Harvie-Weare(HW) model, the mixing triple interaction parameter of ΨLi,Na,SO4at (288 and 308) K and the solubility equilibriumconstants Kspof solid phases Ls, Db1,Db2, Th, and Mir at (288 and 308) K, which are not reported in theliterature, were acquired by fitting the experimental solubility dataof the ternary system (Li2SO4+ Na2SO4+ H2O) by the lease-square method. A comparisonbetween the calculated and experimental results at (288 and 308) Kfor the ternary system shows that the predicted solubilities obtainedwith the extended HW model agree well with experimental data. [ABSTRACT FROM AUTHOR]