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The underground brines are large reserves of valuable mineral resources. Aiming at the underground brines of western Sichuan Basin, the phase equilibria of quinary system KCl–KBr–K2SO4–K2B4O7–H2O and its quaternary subsystem KBr–K2SO4–K2B4O7–H2O were studied by using the method of isothermal dissolution equilibrium at 373 K. The phase diagrams, water content diagrams and density-composition relationship diagrams of above two systems were plotted by using the experimental data, respectively. The results show that the quaternary system KBr–K2SO4–K2B4O7–H2O belongs to a simple type; it consists of three univariant curves, one invariant point and three crystallization regions (K2B4O7⋅4H2O, K2SO4, and KBr). The equilibrium phase diagram (saturated with K2SO4) in the quinary system KCl–KBr–K2SO4–K2B4O7–H2O is a type of solid solution, and there are two crystallization regions (K2B4O7⋅4H2O, solid solution K(Cl,Br)) (saturated with K2SO4), one univariant curve and no invariant point.

The isothermal equilibrium method was used to study the stable phase equilibria of the quinary system Li+, K+, Mg2+//Cl‒, $${{{\text{B}}}_{{\text{4}}}}{\text{O}}_{7}^{{2 - }}$$ –H2O at 273 K. The solubility data of each component in this system were measured through experiments, and the isothermal phase diagram of this system was also drawn. For the identification of the equilibrium solid phases of the invariant points, X-ray diffraction characterization was used. The projection surface of the stable phase diagram of the quinary system Li+, K+, Mg2+//Cl‒, $${{{\text{B}}}_{{\text{4}}}}{\text{O}}_{7}^{{2 - }}$$ ‒H2O at 273 K was drawn under the saturation condition of MgB4O7. The simplified dry-salt diagram has carnallite (KCl·MgCl2·6H2O) and lithium carnallite (LiCl·MgCl2·7H2O), and it contains eleven univariate solubility curves, five invariant points and seven crystallization regions corresponding to K2B4O7·4H2O, Li2B4O7·3H2O, KCl, MgCl2·6H2O, and LiCl·2H2O and double salts carnallite (KCl·MgCl2·6H2O) and lithium carnallite (LiCl·MgCl2·7H2O). In the quinary system, by comparing the area of each crystalline phase zone, lithium chloride is a highly soluble salt, therefore, in the solubility diagram, in comparison with magnesium tetraborate, it corresponds to the smallest crystallization area.

The isothermal dissolution method was used to study the stable phase equilibria in the simple quaternary system Li+//Cl–, S $${\text{O}}_{4}^{{2 - }}$$ , B4 $${\text{O}}_{7}^{{2 - }}$$ –H2O and reciprocal quaternary system Li+, Mg2+//Cl–, B4 $${\text{O}}_{7}^{{2 - }}$$ –H2O at 273 K. The stable phase equilibrium of simple quaternary system Li+//Cl–, S $${\text{O}}_{4}^{{2 - }}$$ , B4 $${\text{O}}_{7}^{{2 - }}$$ –H2O belongs to hydrate type I, and there is no complex salt. The phase diagram is constituted of an invariant point, three univariant solubility curves, and three solid phase crystalline regions. The stable phase equilibrium of reciprocal quaternary system Li+, Mg2+//Cl–, B4 $${\text{O}}_{7}^{{2 - }}$$ –H2O belongs to complex type, and the double salt of lithium carnallite (LiCl·MgCl2·7H2O) is found. There are three invariant points, seven univariant solubility curves, and five solid phase crystalline regions.

In this work, the activity coefficients of sodium nitrate in the ternary system NaNO3–Cu(NO3)2–H2O were experimentally determined at 298.15 K in the range of total ionic strength I = 0.01 – 1.00 mo...

In the process of mineralization and the extraction, the solubilities of metal minerals are affected by chlorides of alkali and alkaline earth metals, such as NaCl, KCl, MgCl2 and CaCl2, the studies on solubilities of chloride minerals in solutions are of significance for the separation and enrichment of elements in hydrometallurgy. To study the solubility relationships of minerals (such as KCl, MgCl2 and ZnCl2) in aqueous solutions, the phase equilibria of the quaternary system KCl−MgCl2−ZnCl2−H2O at 323 K were investigated by means of the isothermal dissolution equilibrium method. These investigations were carried out and the mineral solubilities were measured. The dry salt phase diagram and water content diagram were plotted and there are three double salts formations of MgZnCl4·6H2O, KMgCl3·6H2O (Car) and 2KCl·ZnCl2. The dry salt phase diagram contains four invariant points and nine isothermal solubility curves, which divide the phase diagram into six crystallization regions, and the crystallization regions correspond to the existence of six equilibrium solid phases, namely ZnCl2, 2KCl·ZnCl2, MgZnCl4·6H2O, MgCl2·6H2O (Bis), Car and KCl. The crystallization zone of KCl is the largest, and those of ZnCl2 and MgCl2·6H2O are the smallest. In addition, the equilibrium solid phases at the invariant points of ternary subsystems at 323 K and 373 K were compared and discussed.

The stable phase equilibrium of the two ternary systems LiCl–MgCl2–H2O and SrCl2–MgCl2–H2O at 333 K were researched by using the isothermal dissolution equilibrium method. The solubilities of salts...

In this paper, a sodium ion selective electrode (Na-ISE) and a bromide ion selective electrode (Br-ISE) were used to form a liquid-free potential reversible battery: Na-ISE|NaBr (m1) and SrBr2 (m2)...

Mineral solubilities in the ternary system MgCl2 + SrCl2 + H2O and the quaternary system NaCl + MgCl2 + SrCl2 + H2O at 288 K were measured using the isothermal dissolution equilibrium method. Two p...

To provide theoretical data for the hydrometallurgical process of lead–zinc ores and the separation process of secondary lead recovery, the quaternary system MgCl2–PbCl2–ZnCl2–H2O at 323 K was inve...

The solubility relationships of the ternary systems KCl–PbCl2–H2O and MgCl2−PbCl2–H2O at 323 K were studied by the isothermal dissolution equilibrium method in this article. In the KCl–PbCl2–H2O sy...

The phase equilibria of the ternary system NaCl–SrCl2–H2O at 273 and 308 K and quaternary system LiCl–NaCl–SrCl2–H2O at 308 K were measured by the isothermal dissolution equilibrium method. The pha...

Currently, little is known regarding the value of quantitative parameters derived from the intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) with integrated slice-specific shimming (iShim) sequence in detecting old myocardial infarction and myocardial fibrosis. This study was to investigate the value of IVIM-MRI with iShim sequence in diagnosing old myocardial infarction and fibrosis. Thirty-five patients with both old myocardial infarction and myocardial fibrosis and 12 healthy volunteers were prospectively enrolled to undergo cardiac diffusion-weighted imaging (DWI) using seven b-values (0, 20, 60, 80, 120, 200 and 600 s/mm2). The iShim sequence was used for IVIM data acquisition, and the diffusion parameters, D, D* and f values for IVIM, and conventional apparent diffusion coefficient (ADC) were evaluated on the anterior, posterior and lateral walls of the ventricular septum using the short axis of the heart. Significant differences were found in the D, D* and f values between healthy subjects and patients with old myocardial infarction and myocardial fibrosis (P = 0.000), with the median value of the D and f significantly smaller in the myocardial infarction and fibrosis than in the normal control but the median value of D* significantly greater in the myocardial infarction and fibrosis than in the normal control. In the receiver operating curve analysis, the areas under the curve were 0.939, 0.988 and 0.959 for the D, D* and f values, respectively. The sensitivities and specificities were 84.6% and 94.4% for D, 88.9% and 84.6% for D* and 100% and 93.1% for the f values, respectively. In conclusion, the IVIM-derived parameters (D, D* and f) obtained using the iShim DWI technique showed high capacity in diagnosing old myocardial infarction and myocardial fibrosis by providing diffusion and perfusion information, which may have great importance in future clinical practice.

The mean activity coefficients of KCl in the ternary system KCl–CuCl2–H2O were experimentally determined at a temperature of 298.15 K by the EMF method (electromotive force measurement) via a batte...

The ternary system LiCl–SrCl2–H2O and the quaternary system KCl–LiCl–SrCl2–H2O at 308 K were investigated using the isothermal dissolution equilibrium method. According to the obtained experimental...

The solubility relationships of the ternary systems ZnCl2–MgCl2–H2O and ZnCl2–PbCl2–H2O at 323 K were studied by isothermal dissolution equilibrium method in this work. For the ternary system ZnCl2...

The stable phase equilibria of the ternary system MgCl2 + SrCl2 + H2O and the two quaternary systems NaCl + MgCl2 + SrCl2 + H2O and KCl + MgCl2 + SrCl2 + H2O at 373 K were investigated using an isothermal method. Based on the experimental results, the isothermal solubility diagram of the ternary system MgCl2 + SrCl2 + H2O, and the solubility diagrams and water content diagrams of the two quaternary systems were constructed. The results show that the ternary system MgCl2 + SrCl2 + H2O at 373 K belongs to the simple co-saturated type without complex salt or solid solution. There are two invariant points, three univariant curves and three crystallization fields corresponding to SrCl2·2H2O, SrCl2·H2O and MgCl2·6H2O. The quaternary system NaCl + MgCl2 + SrCl2 + H2O at 373 K is of the simple co-saturated type and no complex salt or solid solution are found. The phase diagram contains two invariant points, five univariant curves and four crystallization fields (where the solids are NaCl, MgCl2·6H2O, SrCl2·H2O and SrCl2·2H2O). The system KCl + MgCl2 + SrCl2 + H2O at 373 K has a double salt named carnallite (KCl·MgCl2·6H2O) without solid solution formation. The phase diagram contains three invariant points, seven univariant curves and five crystallization fields (where the solids are KCl, MgCl2·6H2O, SrCl2·H2O, SrCl2·2H2O and KCl·MgCl2·6H2O).

The stable phase equilibria of the ternary system CaCl2–SrCl2–H2O and the quaternary system KCl–CaCl2–SrCl2–H2O at 373 K were investigated by means of the isothermal dissolution equilibrium method. According to experimental results, the phase diagrams of the two systems were plotted. The results show that the ternary system CaCl2–SrCl2–H2O at 373 K belongs to the simple cosaturated type, without complex salt or solid solution. There are one invariant point, two univariant curves, and two crystallization fields (where the solids are SrCl2·H2O and CaCl2·2H2O). The quaternary system KCl–CaCl2–SrCl2–H2O at 373 K has a double salt, chlorocalcite (KCl·CaCl2). The phase diagram contains two invariant points, five univariant curves, and four crystallization fields (where the solids are KCl, CaCl2·2H2O, SrCl2·H2O, and KCl·CaCl2).

The stable phase equilibria of the quaternary systems LiCl–KCl–MgCl2–H2O and Li2B4O7–Na2B4O7–MgB4O7–H2O at 273 K were studied using isothermal stable equilibrium method and the solubilities of the salts in the systems were also determined in turn. According to the experimental data and the corresponding equilibrium solid phases, the isothermal solubility diagrams, water content diagrams about two systems at 273 K were plotted, respectively. The first system has two double salts LiCl·MgCl2·7H2O and KCl·MgCl2·6H2O at 273 K, and its isothermal phase diagram of this system includes three invariant points, seven univariate curves, and five crystalline areas, those are LiCl·2H2O, MgCl2·6H2O, KCl, LiCl·MgCl2·7H2O and KCl·MgCl2·6H2O, respectively. The second system has no complex salt or solid solution and the system belongs to a simple cosaturated type, and its stable phase diagram is constituted by an invariant point, three univariant solubility curves, and three solid phase crystalline regions, where the three...

The stable phase equilibria of LiBr–NaBr–SrBr2–H2O were studied at 323.15 K and 308.15 K by the isothermal solution equilibrium method. The isothermal phase diagram of the quaternary system was drawn by using solubilities of salts and solid phase identification. The X-ray powder diffraction method was used to identify the corresponding equilibrium solid phases of the invariant points in the quaternary system. The quaternary system LiBr–NaBr–SrBr2–H2O at 323.15 K has no double salts or solid solution. There are two invariant points, five univariant curves, and four crystallization fields corresponding to LiBr•H2O, NaBr, SrBr2•2H2O, and SrBr2•6H2O respectively, of which NaBr has the largest crystallization field, indicating that its solubility is the smallest and it is the easiest to be precipitated from the saturated solution. The phase diagram of quaternary system LiBr-NaBr-SrBr2-H2O at 308.15 K has three invariant points, seven univariant curves, and five crystallization fields corresponding to LiBr•2H2O, NaBr, NaBr•2H2O, SrBr2•2H2O, and SrBr2•6H2O, respectively. Among them, the crystallization field of LiBr•2H2O is the smallest, indicating that the solubility of LiBr•2H2O in this system is the largest.

The two quaternary systems NaBr–SrBr2–MgBr2–H2O and KBr–SrBr2–MgBr2–H2O at 323 K were constructed by the isothermal dissolution equilibrium method. The mass fraction of every component of the equilibrium liquid phase in the two systems at 323 K was calculated. The phase diagrams and water content diagrams were plotted in accordance with the Janecke indices of salts and water. The system NaBr–SrBr2–MgBr2–H2O at 323 K has two invariant points, five univariant curves, and four solid phase crystallization areas, which correspond to strontium bromide hexahydrate (SrBr2·6H2O), magnesium bromide hexahydrate (MgBr2·6H2O), sodium bromide (NaBr), and sodium bromide dihydrate (NaBr·2H2O). The system KBr–SrBr2–MgBr2–H2O at 323 K has double salt (KBr·MgBr2·6H2O) without solid solution formation. It has two invariant points, five univariant curves, and four solid phase crystallization areas corresponding to strontium bromide hexahydrate (SrBr2·6H2O), magnesium bromide hexahydrate (MgBr2·6H2O), double salt (KBr·MgBr2·6...

The underground brine of the Sichuan Basin is rich in liquid mineral resources such as strontium and potassium. In order to realize the comprehensive utilization of resources and utilize the underg...

Solubilities of ternary system (KCl-SrCl2-H2O) were determined using the isothermal dissolution equilibrium method at 273 and 308 K. According to the obtained experimental results, the phase diagrams of the system at 273 and 308 K were plotted respectively. The results show that the ternary system has a invariant point, two univariate solubility curves and two crystallization regions corresponding to KCl and SrCl2•6H2O at 273 and 308 K, no solid solution was found in the phase diagram. Based on Pitzer and H-W model, the Pitzer single salt parameters of KCl (β(0), β(1), Cϕ) and SrCl2 (β(0), β(1), β(2), Cϕ) and the interaction parameters of mixed ions (θK, Sr, ΨK, Sr, Cl) were used to calculate the solubilities of the ternary system at 273 and 308 K, and the results show that the calculated values agree well with the experimental values in this work.

Since various mineral elements (such as sodium, potassium, strontium, bromine) are rich in underground brine in Sichuan Basin of China, to utilize the bromine resources rationally, the phase equilibria of the quaternary systems NaBr + KBr + SrBr2 + H2O, NaBr + MgBr2 + SrBr2 + H2O and their subsystems at 273.15 K were studied with the means of isothermal dissolution equilibrium method. The research systems are three ternary systems (NaBr + SrBr2 + H2O, KBr + SrBr2 + H2O and MgBr2 + SrBr2 + H2O) and two quaternary systems (NaBr + KBr + SrBr2 + H2O and NaBr + MgBr2 + SrBr2 + H2O). The corresponding solubility phase diagrams of the research systems listed above were plotted based on the measured experimental data. The experimental results indicate that there is no formation of solid solution or double salts in five systems. Five phase diagrams all belong to hydrate type I and contain one invariant point. In three ternary systems, there are two isothermal solubility curves and two crystallization fields, and the equilibrium solid phases are NaBr•2H2O and SrBr2•6H2O in the ternary system NaBr + SrBr2 + H2O, KBr and SrBr2•6H2O in the ternary system KBr + SrBr2 + H2O, and MgBr2•6H2O and SrBr2•6H2O in the ternary system MgBr2 + SrBr2 + H2O, respectively. There are three isothermal solubility curves and three crystallization fields in two quaternary systems. The equilibrium solid phases are NaBr•2H2O, KBr, and SrBr2•6H2O in the quaternary system NaBr + KBr + SrBr2 + H2O. In the quaternary system NaBr + MgBr2 + SrBr2 + H2O, the salts NaBr•2H2O, MgBr2•6H2O and SrBr2•6H2O coexist at the invariant point. The unreported mixing ion-interaction parameters of Pitzer equations θMg, Sr, ΨMg, Sr, Br, ΨNa, Sr, Br, and ΨK, Sr, Br are fitted with the solubility data at 273.15 K. The Pitzer ionic interaction model and the required parameters were employed to predict the solubilities of salts in five systems. The calculated results show that the predicted values are in accordance with the measured data, which verify the reliability of the selected parameters.

Using the method of isothermal dissolution equilibrium, stable phase equilibria of unreported strontium-containing systems LiCl–NaCl–SrCl2–H2O and LiCl–KCl–SrCl2–H2O at 298 K have been studied in accordance with the compositions of the underground brine in western Sichuan Basin. The experimental results show that there are no solid solution and complex salt in two quaternary systems. The phase diagram of quaternary system LiCl–NaCl–SrCl2–H2O consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The quaternary system LiCl–KCl–SrCl2–H2O belongs to a simple type and the phase diagram consists of two invariant points, five isothermal dissolution curves and four crystallization regions. The solubilities of salts in the above systems were accurately calculated with Pitzer electrolyte solution theory. It was found that the calculated phase diagrams coincided basically with the experimental phase diagrams by evaluated the accuracy through the experimental results. Meanwhile, the applicability of Pitzer parameters selected in this paper was validated.