Simple Eutectic Type Research Articles

Physicochemical and thermoelectric properties of alloys of the CoSb0.82–Sn system

The [Formula: see text]–Sn section of the Co–Sb–Sn ternary system was studied by methods of physicochemical analysis. It is shown that the section is quasi-binary, its phase diagram is of a simple eutectic type, with a limited region of solid solutions based on [Formula: see text], the boundary of which at room-temperature reaches [Formula: see text] mol% Sn. The temperature dependences of some thermoelectric parameters of ([Formula: see text])[Formula: see text][Formula: see text] solid solutions have been studied. The thermodynamic functions of a pure [Formula: see text] and a solid solution alloy of composition (CoSb[Formula: see text])[Formula: see text]Sn[Formula: see text] are calculated.

Ternary SLE Measurements for the Systems H2O+ZnCl2+Zn(H2PO2)2 at T= (298, 313 and 333) K

The solid-liquid equilibrium (SLE) of H2O+ZnCl2+Zn(H2PO2)2 ternary system at 298, 313 and 333 K have been studied with the use of isothermal method. Solid phase compositions have been determined with Schreinemaker’s method. H2O+ZnCl2+Zn(H2PO2)2 ternary systems have simple eutectic type in 298, 333K. One invariant point, two invariant curves and two crystallization region have been observed in the phase diagrams at 298, 333K. Otherwise, One invariant point, three invariant curves and two crystallization region have been observed in the phase diagrams in 313K. In the crystallization regions; (i) Zn(H2PO2).H2O and ZnCl2, (ii) Zn(H2PO2)2, Zn(H2PO2).H2O and ZnCl2, (iii) Zn(H2PO2)2 and ZnCl2 salts have been observed at 298 K, 313K, and 333 K, respectively. In H2O+ZnCl2+Zn(H2PO2)2 ternary system, the increasing salting-out effect of Zn(H2PO2)2 on ZnCl2 with temperature.

Solid-Liquid Equilibrium and Phase Diagram of Organic System Forming Simple Eutectic

The study of phase diagram guided with solid-liquid equilibrium (SLE) data at different molar composition in two component systems serve as a basic roadmap for the material synthesis, and also provide in-depth study of physicochemical and thermochemical properties of synthesized materials. The solid-liquid equilibrium data of binary organic system, acetanilide – acetamide (ACN-ACT) is determined by thaw melt method. The system exhibits simple eutectic type phase diagram at 0.20 molar composition of ACN with congruent melting temperature 52oC.

Solid–Liquid Phase Equilibria of the Aqueous Ternary System (Li2CO3 + Na2CO3 + H2O) at (278.15 to 308.15) K

The phase equilibria of the ternary system (Li2CO3–Na2CO3–H2O) at 278.15 ≤ T/K ≤ 308.15 K were investigated by isothermal dissolution equilibrium. On the basis of the experimental data, the phase diagrams and densities versus mass fraction (100w) of sodium carbonate were plotted. For the ternary system, there is one invariant point, two univariant curves, and two crystallization regions corresponding to lithium carbonate (Li2CO3, LC) and sodium carbonate decahydrate (Na2CO3·10H2O, NC10) or thermonatrite (Na2CO3·H2O, NC). No solid solution or double salt was found in the ternary system at the experimental temperature; the ternary system was a simple eutectic type. In a comparison of the phase diagrams from 278.15 to 308.15 K in the system, the crystallization region of NC10 existed at 278.15, 288.15, and 298.15 K, and the equilibrium solid phase corresponding to sodium carbonate was dehydrated and transformed to thermonatrite at 308.15 K. The crystallized area of lithium carbonate expands with increasing temperature, while the crystallized areas of sodium carbonate demonstrate an opposite trend. The components of Na2CO3 in solution have a common ion and salting-in effect to Li2CO3, and the salting-in effect increases with increasing concentration. This indicates that a large amount of excess sodium carbonate could not improve the yield of lithium in the carbonated precipitated lithium process. The density of this ternary system changes regularly with the changing concentration of sodium carbonate, and it was represented by empirical equations as functions of concentration.

Solid-liquid phase equilibrium determination and correlation of ternary systems NH4Cl+AlCl3+H2O, MgCl2+AlCl3+H2O and SrCl2+AlCl3+H2O at 298 K

The equilibrium data (solubility, density and refractive index) of three aqueous ternary systems NH4Cl + AlCl3+H2O, MgCl2+AlCl3+H2O, and SrCl2+AlCl3+H2O at 298 K were measured by isothermal dissolution method, and the corresponding diagrams were plotted. The phase diagram shows that these three systems are simple eutectic type, and neither double salt nor solid solution formed. Three ternary systems all have one ternary invariant point, two isothermal dissolution curves and two crystallization fields. The equilibrium thermodynamics data of three aqueous ternary systems at 298 K were correlated by using the Pitzer thermodynamic model. Result shows that the calculated values are consistent well with the experimental ones.

Phase Equilibria and Phase Diagrams for the Ternary Aqueous System Containing Lithium, Sodium, and Pentaborate Ions at 298.15 and 323.15 K and 101.325 kPa

Phase equilibria and phase diagrams for the ternary aqueous system containing lithium, sodium, and pentaborate ions at 298.15 and 323.15 K and 101.325 kPa were investigated by the methods of isothermal dissolution equilibrium. From the experimental data, the phase diagrams and the diagrams of physicochemical properties versus composition of lithium pentaborate in the equilibrium systems were plotted, respectively. The phase diagrams of the ternary system LiB5O8 + NaB5O8 + H2O at two temperatures contain one invariant point, two univariant curves, and two crystallization regions corresponding to sodium pentaborate pentahydrate (NaB5O8·5H2O) and lithium pentaborate pentahydrate (LiB5O8·5H2O). Due to the different dissolution behaviors of pentaborate salts in the aqueous systems, the component of LiB5O8 has a relatively strong effect on the solubility of NaB5O8. It was found that this system belongs to a simple eutectic type at two temperatures, and neither double salts nor solid solutions were formed. The densities and refractive indices in the ternary system at 298.15 and 323.15 K are as similar as changing regularly with the increase of LiB5O8 concentration. On the basis of empirical equations of the density and refractive index in electrolytes, the calculated values of density and refractive index agreed well with the experimental values at two temperatures.

Solid–Liquid Phase Equilibria in the Ternary Aqueous Systems (NaB5O8 + KB5O8 + H2O) and (LiB5O8 + KB5O8 + H2O) at 298.15 K and 101.325 kPa

Solid–liquid phase equilibria of the ternary systems (NaB5O8 + KB5O8 + H2O) and (LiB5O8 + KB5O8 + H2O) at T = 298.15 K and p = 101.325 kPa were investigated, using a combination of the methods of isothermal dissolution equilibrium and the wet-residue solid phase (Schreinemarker’s rule). From the experimental results, the phase diagrams and the diagrams of physicochemical properties versus composition were drawn for each system. The phase diagrams of the systems (NaB5O8 + KB5O8 + H2O) and (LiB5O8 + KB5O8 + H2O) at 298.15 K contain one invariant point, two univariant curves and two crystallization regions. The area of the crystallization region of KB5O8·4H2O is much larger than that of NaB5O8·5H2O in the former system and that of LiB5O8·5H2O in the later system. Owing to the different solubilities of the salts in the aqueous systems, the solubility of KB5O8 in the solution decreased obviously with increasing concentration of NaB5O8 or LiB5O8 in either ternary system, indicating that both NaB5O8 or LiB5O8 have a relatively strong effect on the solubility of KB5O8. It was found that both systems belong to the simple eutectic type, and neither double salts nor solid solutions were formed. The distribution behaviors of densities and refractive indices in the two ternary systems at 298.15 K are similar and change regularly with increasing KB5O8 concentration in each system. The density and refractive index calculated on the basis of empirical equations of salt–water electrolytes agree well with the experimental values.

Solid-liquid Equilibria in the Ternary Systems (NaCl+SrCl2+H2O) and (KCl+SrCl2+H2O) at 288.15 K and 0.1 MPa

Solid-liquid phase equilibria of the two ternary systems (NaCl+SrCl2+H2O) and (KCl+SrCl2+H2O) at T=288.15 K and p=0.1 MPa were studied using the isothermal dissolution equilibrium method. Solubilities of the equilibrium liquid phase were determined, and the solids were also investigated by the Schreinemaker method of wet residues. In the ternary system (NaCl+SrCl2+H2O) at 288.15 K, there is one invariant point corresponding to (NaCl+SrCl2·6H2O) and two crystallization regions corresponding to NaCl and SrCl2·6H2O. The crystallized area of SrCl2·6H2O decreased with the increasing temperature, while that of NaCl increased slightly. In the ternary system (KCl+SrCl2+H2O) at 288.15 K, there is one invariant point(KCl+SrCl2·6H2O) and two crystallization regions cor-responding to KCl and SrCl2·6H2O. Both systems belong to a simple eutectic type, and neither double salts nor solid solutions were formed. On the basis of Pitzer-Harvie-Weare model, the solubilities of the two systems at 288.15 K were demonstrated. A comparison showed that the calculated solubilities agreed well with the experimental data.

Solid-liquid phase equilibria of ternary system Na2S2O3-Na2SO4-H2O in a wide range of temperatures: Measurement and application

Abstract In order to provide a fundamental basis for treatment of wastewater from desulfurization of coke oven gas to recover pure salt, solid-liquid equilibrium data of Na2S2O3-Na2SO4-H2O system at T = (278.15, 283.15, 291.15, 333.15 or 353.15) K were measured. The experimental data was obtained using the isothermal solution saturation method and Schreinemaker’s wet residue method. The solid-liquid phase diagrams of the ternary system were constructed. The ternary phase diagrams turned out to be simple eutectic type containing one invariant point, two univariant curves, and two single-salt crystallization regions. It was found that the crystallization region of Na2SO4 is larger than that of Na2S2O3 and expands with the increasing of temperature. But the crystallization region of Na2S2O3 decreases with the increasing of temperature. Through analyzing the thermodynamic characteristics of Na2S2O3 and Na2SO4, two crystallization methods for separating the mixture of Na2S2O3-Na2SO4 were put forward. A simple comparison of the two crystallization methods was carried out.

Crystallization and Simulation Studies in m-Dinitrobenzene–p-Chloroaniline Eutectic System

Thaw-melt method showed that the phase diagram of m-dinitrobenzene (m-DNB)–p-chloroaniline (p-CA) system belongs to simple eutectic type. The kinetics of solidification followed Hillig and Turnbull’s equation. Excess thermodynamic functions and FT-IR spectral studies indicated some weak interaction between the component molecules in the eutectic. The mechanical strength of the eutectic was found to be higher than those of its components. Molecular stability was predicted on the basis of frontier molecular orbital analysis. The value was found to be 0.06073 a.u. for eutectic, indicating. the possibility of charge transfer interaction during the eutectic formation. Results showed that the eutectic is stabilized by hydrogen-bond formation. Calculated interaction energy of reactants and eutectic was found to be–17.4 kJ mol–1.

Experimental and thermodynamic modeling study of solid-liquid equilibrium in ternary systems NaBr–SrBr2–H2O and KBr–SrBr2–H2O at 288.15 K and 0.1 MPa

The solubilities and refractive indices of the NaBr–SrBr2–H2O and KBr–SrBr2–H2O systems at 288.15K were investigated with the isothermal dissolution method. The phase diagrams and refractive index diagrams were plotted for the two systems at 288.15K. The phase diagrams consist of one two-salt cosaturated invariant point, two univariant solubility isotherms, and two stable crystallization fields. The two systems belong to the simple eutectic type, and neither double salt nor solid solution was found. The refractive indices change regularly with the strontium bromide concentration increasing in solution, and reach the maximum value at the eutectic point. On the basis of Pitzer and Harvie-Weare (HW) model, the binary and mixing Pitzer parameters and solubility equilibrium constants of equilibrium solid salts for the two ternary systems at 288.15K were acquired. And then, the solubilities for the ternary systems at 288.15K were demonstrated. A comparison shows that the calculated solubilities agree well with the experimental data.

Measurement and correlation of solid–liquid phase equilibria for binary and ternary systems consisting of N -vinylpyrrolidone, 2-pyrrolidone and water

The solid–liquid equilibria (SLE) for binary and ternary systems consisting of N-Vinylpyrrolidone (NVP), 2-Pyrrolidone (2-P) and water are measured. The phase diagrams of NVP (1) + 2-P (2), NVP (1) + water (2), NVP (1) + 2-P (2) + 1 wt% water (3) and NVP (1) + 2-P (2) + 2 wt% water (3) are identified as simple eutectic type with the eutectic points at 263.75 K (x1E = 0.5427), 251.65 K (x1E = 0.3722), 260.25 K (x1E = 0.5031) and 256.55 K (x1E = 0.4684), respectively. The phase diagram of 2-P (1) + water (2) has two eutectic points (x1E = 0.1236, T E= 259.15 K and x1E = 0.7831, T E= 286.15 K) and one congruent melting point (x1C = 0.4997, TC = 303.55 K) because of the generation of a congruently melting addition compound: 2-P·H2O. The ideal solubility and the UNIFAC models were applied to predict the SLE, while the Wilson and NRTL models were employed in correlating the experimental data. The best correlation of the SLE data has been obtained by the Wilson model for the binary system of NVP + 2-P. The UNIFAC model gives more satisfactory predictions than the ideal solubility model.

The solidification behavior and phase equilibrium of o-Nitroaniline-β-Naphthol binary eutectic system

ABSTRACTPhase diagram studies of o-nitroaniline-β-naphthol system have been made by the thaw melt method. Simple eutectic type phase diagram was formed. Formation of eutectic mixture occurred at 0.7222 mole fractions of o-nitroaniline and melted at 326.85 K. The heat of fusion of components and eutectic mixtures were determined with the help of DSC technique and excess thermodynamic functions were calculated. Experiments were performed to study the undercooling, microstructure and linear velocities of crystallization. Flexural strength measurements were also made. Eutectic mixture showed higher flexural strength as compared to the components.

Solid–Liquid Equilibrium in the Aqueous System Containing the Borates of Potassium, Rubidium, and Magnesium at 348 K

The stable phase equilibrium and phase diagram of the quaternary system K+, Rb+, Mg2+ // borate·H2O at 348 K were determined by isothermal dissolution method. The densities, refractive indices, and solubility values of the equilibrated solution in the quaternary system were measured. The crystalloid forms of the solid phase of invariant point were identified by X-ray diffraction method. The stable phase diagram, water content diagram, and the diagrams of the densities/refractive indices versus composition were plotted based on the measured data. Results show that this quaternary system at 348 K without double salt or solid solution formed belongs to a simple eutectic type. The invariant point E saturated with three salts corresponding to potassium tetraborate tetrahydrate (K2B4O5(OH)4·2H2O), rubidium pentaborate tetrahydrate (RbB5O6(OH)4·2H2O), and hungchaoite (MgB4O5(OH)4·7H2O). The crystallization field of RbB5O6(OH)4·2H2O is the maximum, meaning that it has the smallest solubility among the coexisting salts. On the solubility curves AE (cosaturated with salts MgB4O5(OH)4·7H2O and RbB5O6(OH)4·2H2O) and BE (cosaturated with salts K2B4O5(OH)4·2H2O and RbB5O6(OH)4·2H2O), the water content decreases, the densities and refractive indices increase with the increase of J(K2B4O7); on the curve CE (cosaturated with salts MgB4O5(OH)4·7H2O and K2B4O5(OH)4·2H2O), the water content and the densities increase, the refractive indices decrease with the increase of J(K2B4O7).

Measurement and Application of a Solid–Liquid Equilibrium for the Ternary NaCl + Na2S2O3 + H2O System

Solid–liquid equilibrium data for the NaCl + Na2S2O3 + H2O system at 283.15 and 303.15 K were measured using the method of isothermal solution saturation combined with a moist residue method of Schreinemaker, the equilibrium solid phase was identified by powder X-ray diffraction, and finally the solid–liquid phase diagrams of the ternary system were constructed. The ternary NaCl + Na2S2O3 + H2O phase diagrams at 283.15 and 303.15 K turned out to be of the simple eutectic type. One invariant point, two univariant curves, and two crystallization regions exist in each of the phase diagrams. The crystallization region of NaCl is larger than that of Na2S2O3·5H2O at 283.15 K, and the crystallization region of NaCl expands while that of Na2S2O3·5H2O decreases when the temperature rises to 303.15 K. Consequently, the invariant point at 303.15 K is located in the Na2S2O3·5H2O single-salt crystallization region of the phase diagram at 283.15 K. On the basis of this thermodynamic characteristic, a method for separation of the NaCl + Na2S2O3 mixture was proposed, from which both of the pure salts could be obtained.

Phase Equilibrium for the Ternary System K2SO4 + KCl + H2O in Aqueous Solution at 303.15 K

The ternary system of K2SO4 + KCl + H2O at 303.15 K was studied by the method of isothermal solution saturation and wet residues. The solubility and density of the system were determined and the equilibrium solids were also investigated by the Schreinemaker’s method and verified by X-ray diffraction. On the basis of the experimental data, the phase diagram and the diagram of density versus composition were plotted. The ternary system had two uninvariant curves, one cosaturated point (K2SO4 + KCl), and two crystalline regions corresponding to K2SO4 and KCl. The crystallization region of K2SO4 was much larger than that of KCl. The system was a simple eutectic type, in which neither double salt nor solid solution was formed. The research can offer meaningful data support for industry and a forthcoming study. These data could be conducive to the processes of separation and crystallization in the chemical industry.

Thermodynamics Phase Equilibria of the Aqueous Ternary Systems LiCl + KCl (MgCl2) + H2O at 348 K

The thermodynamics phase equilibria of the aqueous ternary systems LiCl + MgCl2 + H2O and LiCl + KCl + H2O at 348 K were investigated using an isothermal evaporation method. The solubilities and physicochemical properties such as density and refractive index of the equilibrated solution were determined. The compositions of solid phases were confirmed using the Scherinemakers’ wet residue method. In accordance with the experimental data, the phase diagrams and physicochemical vs composition diagrams were constructed. The ternary system LiCl + MgCl2 + H2O is of a complex type with double salt LiCl·MgCl2·7H2O (lithium carnallite) formed at 348 K, and its phase diagram consists of two invariant points, three univariant curves, and three crystallization fields corresponding to lithium chloride monohydrate (LiCl·H2O), magnesium chloride hexahydrate (MgCl2·6H2O), and lithium carnallite (LiCl·MgCl2·7H2O). The ternary system LiCl + KCl + H2O is of a simple eutectic type at 348 K, and its phase diagram is composed of one invariant point, two univariant curves and two crystallization fields corresponding to potassium chloride (KCl) and lithium chloride monohydrate (LiCl·H2O). Lithium chloride has a salting out effect on magnesium chloride or potassium chloride. Comparisons between the metastable and stable phase diagrams at 348 K of these two ternary systems have been drawn. In the system LiCl + MgCl2 + H2O, the crystallization region of MgCl2·6H2O under the metastable equilibrium is smaller, while the crystallization region of the LiCl·MgCl2·7H2O is larger. In the system LiCl + KCl + H2O, the crystallization regions of LiCl·H2O and KCl under metastable equilibrium are both smaller. Comparisons between the metastable phase diagrams of system LiCl + KCl + H2O at (298, 323, and 348) K show that the crystallization region of LiCl·H2O increased with the rise of temperature, whereas the crystallization region of salt KCl is decreased.

Solid-liquid equilibria in the quaternary system Na+, K+//Br−, B4O7 2−-H2O at 298 K

According to the compositions of the underground gasfield brines in the west of Sichuan Basin, the solubilities and densities of the solid-liquid equilibria in the quaternary system Na+, K+//Br−, B4O72−-H2O at 298 K were determined by the method of isothermal solution saturation. From the experimental data, the phase diagram, water content diagram and density-composition diagram were obtained. This quaternary system is of simple eutectic type, without double salt and solid solution. There are two invariant points, five univariant curves, four fields of crystallization in the system. The equilibrium solid phases are Na2B4O7·10H2O, K2B4O7·4H2O, NaBr·2H2O and KBr. Na2B4O7·10H2O has a larger crystallization field, and NaBr·2H2O has a smaller crystallization field. It is also found that bromide has the salting-out effect on borate in the quaternary system Na+, K+//Br−, B4O72−-H2O at 298 K.

Phase Equilibrium for the Ternary System NaH2PO4 + Na2SO4 + H2O in Aqueous Solution at 298.15 K

The ternary system (NaH2PO4 + Na2SO4 + H2O) at 298.15 K was investigated by using an isothermal solution saturation method. The solubilities and densities of the solution were determined. According to the experimental results, the phase diagram and the diagram of densities versus composition were plotted. The phases of the equilibrium solids were analyzed by X-ray diffraction (XRD), and crystalline regions of both solid phases were determined. It was found that there were two invariant points (NaH2PO4·2H2O + Na2SO4; Na2SO4 + Na2SO4·10H2O), three univariant curves, and three crystallization regions corresponding to sodium dihydrogen phosphate dihydrate (NaH2PO4·2H2O), sodium sulfate (Na2SO4), and sodium dihydrogen phosphate decahydrate (Na2SO4·10H2O; also known as Glauber’s salt) in this ternary system. The system belonged to a simple eutectic type, and neither double salts nor solid solutions were formed. This research provided missing information of the phase diagram in this ternary system, which in turn...

Solid-Liquid Equilibria for Binary Mixture of Dichlorophenols

Differential Scanning Calorimeter (DSC) was used to investigate the thermal properties of 2,4-dichlorophenol+2,6-dichlorophenol and 2,4-dichlorophenol+2,3-dichlorophenol binary systems. The experimental results showed that The phase diagram of 2,4-dichlorophenol+2,6-dichlorophenol system was a simple eutectic type with the eutectic point at 294.99 K and 0.6200 mole fraction of 2,4dichlorophenol; The phase diagram of 2,4dichlorophenol+2,3dichlorophenol system was a simple eutectic type with the eutectic point at 291.86 K and 0.5834 mole fraction of 2,4dichlorophenol. Furthermore, the activity coefficients of components in mixtures of 2,4dichlorophenol+2,6dichlorophenol and2,4dichlorophenol+ 2,3dichlorophenol binary systems have been correlated by the Wilson model, respectively.