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Solid–liquid phase equilibria of the quaternary system (Li+,K+// , –H2O) and its subsystem are very important for the separation of lithium and potassium salts from the salt lake brines. In this paper, the solubilities, densities, refractive indices and pH values of the reciprocal quaternary system (Li+,K+// , –H2O) at 308.15 K were determined experimentally using the isothermal dissolution method. The dry-salt diagram and water-phase diagram were plotted based on the experimental data. The stable phase diagram contains four invariant points, nine univariant curves and six crystallization regions corresponding to Li2CO3, Li2CO3⋅K2CO3, K2CO3⋅1.5H2O, Li2SO4⋅H2O, K2SO4, and Li2SO4⋅K2SO4. Li2CO3 has the largest crystallization field, whereas the Li2CO3⋅K2CO3 crystallization field is the smallest one. [ABSTRACT FROM AUTHOR]

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]

The solubilities and physicochemical properties, including density and pH, in the ternary system (LiBO + CaBO + HO) at (288.15 and 298.15) K were investigated using the isothermal dissolution equilibrium method. According to the experimental results of the ternary system at (288.15 and 298.15) K, the stable phase diagrams and the diagrams of physicochemical properties were plotted versus composition. In the phase diagrams of the ternary system at (288.15 and 298.15) K, there is one invariant point (LiBO·8HO + CaBO·6HO), two univariant isotherm dissolution curves, and two crystallization regions corresponding to lithium metaborate octahydrate (LiBO·8HO) and calcium metaborate hexahydrate (CaBO·6HO), respectively. This system at both temperatures belongs to hydrate type I classification and neither double salt nor solid solution were found. A comparison of the phase diagrams for the ternary system at (288.15 and 298.15) K shows that the numbers of solid phase and the minerals present are the same; the crystallized area of CaBO·6HO increased at the higher temperature, while that of LiBO·8HO decreased. The physicochemical properties (density and pH values) of the ternary system at the two temperatures change regularly with increasing lithium metaborate concentration. The calculated values of density using empirical equations of the ternary system are in good agreement with the experimental values. [ABSTRACT FROM AUTHOR]

The solubility and density in the thermodynamic phase equilibria ternary system (Li 2 SO 4 + K 2 SO 4 + H 2 O) at 288.15 K and 0.1 MPa were investigated experimentally with the method of isothermal dissolution equilibrium. This system at 288.15 K consists of two invariant points, three univariant isothermal dissolution curves; and three crystallization regions. The salt Li 2 SO 4 ·K 2 SO 4 belongs to the incongruent double salt, and no solid solution was found. Based on the Pitzer model and its extended Harvie–Weare (HW) model, the mixing ion-interaction parameters of θ Li,K , ψ Li,K,SO4 at 288.15 K and the solubility equilibrium constants K sp of solid phases Li 2 SO 4 ·H 2 O and Li 2 SO 4 ·K 2 SO 4 , which are not reported in the literature were acquired. A comparison between the calculated and experimental results at 288.15 K for the ternary system shows that the calculated solubilities obtained with the extended HW model agree well with experimental data. [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]

Schizophrenia, a psychiatric disorder, requires long-term treatment; however, large fluctuations in blood drug concentration increase the risk of adverse reactions. We prepared a long-term risperidone (RIS) implantation system that can stabilize RIS release and established in-vitro and in-vivo evaluation systems. Cumulative release, drug loading, and entrapment efficiency were used as evaluation indicators to evaluate the effects of different pore formers, polymer ratios, porogen concentrations, and oil–water ratios on a RIS implant (RIS-IM). We also built a mathematical model to identify the optimized formulation by stepwise regression. We also assessed the crystalline changes, residual solvents, solubility and stability after sterilization, in-vivo polymer degradation, pharmacokinetics, and tissue inflammation in the case of the optimized formulation. The surface of the optimized RIS microspheres was small and hollow with 134.4 ± 3.5 µm particle size, 1.60 SPAN, 46.7% ± 2.3% implant drug loading, and 93.4% entrapment efficiency. The in-vitro dissolution behavior of RIS-IM had zero-order kinetics and stable blood concentration; no lag time was released for over three months. Furthermore, the RIS-IM was not only non-irritating to tissues but also had good biocompatibility and product stability. Long-acting RIS-IMs with microspheres and film coatings can provide a new avenue for treating schizophrenia. [ABSTRACT FROM AUTHOR]

[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]