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Zeng Y.,Chengdu University of Technology | Zeng Y.,Sichuan Higher Education Institutions | Lin X.,China Steel Corporation | Yu X.,Chengdu University of Technology
Journal of Chemical and Engineering Data | Year: 2012

The aqueous quaternary system Li2SO4 + Na 2SO4 + K2SO4 + H2O is one of the most important subsystems of the sulfate-type salt lake brine located in the Qinghai-Tibet Plateau. The phase equilibria of the aqueous quaternary system Li2SO4 + Na2SO4 + K 2SO4 + H2O were investigated at 273.15 K using an isothermal evaporation method. A sodium and lithium sulfate double salt (3Na2SO4·Li2SO4· 12H2O) and a potassium and lithium sulfate double salt (KLiSO 4) are formed in this quaternary system at 273.15 K. There are three invariant points, seven univariant curves, and five crystallization fields in the phase diagram of this system. The five crystallization fields correspond to sodium sulfate decahydrate (Na2SO4·10H 2O), potassium sulfate (K2SO4), lithium sulfate monohydrate (Li2SO4·H2O), and two double salts KLiSO4 and 3Na2SO4·Li 2SO4·12H2O. The double-salt glaserite (3K2SO4·Na2SO4) is not formed in this system at research temperature. The three invariant points have different attributes, which invariants E1 and E2 are of incommensurate points, whereas invariant E3 is of a commensurate point. The water content and the density of the equilibrated solution change regularly with the mass fraction composition of potassium sulfate. © 2012 American Chemical Society.

Yu X.,Chengdu University of Technology | Zeng Y.,Chengdu University of Technology | Zeng Y.,Sichuan Higher Education Institutions | Zhang Z.,Chengdu University of Technology
Journal of Chemical and Engineering Data | Year: 2012

The metastable phase equilibria in the ternary systems KCl + NH 4Cl + H 2O and NH 4Cl + MgCl 2 + H 2O were investigated at 298.15 K using an isothermal evaporation method. The metastable phase diagrams and the physicochemical properties versus composition diagrams were constructed on the basis of the experimental data. In the phase diagram of the ternary system KCl + NH 4Cl + H 2O, there are three invariant points and five crystallization fields, corresponding to potassium chloride (KCl), ammonium chloride (NH 4Cl), a solid solution based on potassium chloride [(K, NH 4)Cl], a solid solution based on ammonium chloride [(NH 4, K)Cl], and a crystallization field of two kinds of solid solution [(K, NH 4)Cl + (NH 4, K)Cl] precipitation. Comparisons between the metastable and stable phase diagrams at 298.15 K show that the crystallization forms of salts are all the same, whereas the size of crystallization regions has slight changes. The ternary system NH 4Cl + MgCl 2 + H 2O is a complex type system with a double salt ammonium carnallite (NH 4Cl·MgCl 2·6H 2O) formed at 298.15 K. Comparisons between the metastable and the stable phase diagrams at 298.15 K and 323.15 K show that the crystallization forms have not changed, while the crystallization fields have slight changes. The density coefficient A i and refractive index coefficient B i of salts KCl, NH 4Cl, and MgCl 2 at 298.15 K were obtained by fitting. The calculated values of densities and refractive indices agree well with the experimental values, with a maximum relative error better than 0.010. © 2012 American Chemical Society.

Fu C.,Chengdu University of Technology | Sang S.-H.,Chengdu University of Technology | Sang S.-H.,Sichuan Higher Education Institutions | Zhou M.-F.,Chengdu University of Technology | And 2 more authors.
Journal of Chemical and Engineering Data | Year: 2016

Phase equilibria and phase diagram always play an important role to utilize the salt lake brine resources. In this paper, the phase equilibria in two ternary systems Li2B4O7-MgB4O7-H2O and K2B4O7-MgB4O7-H2O at 273 K were studied using the isothermal solubility equilibrium method. The densities and solubilities of the components in these systems listed above were measured. Based on the determined equilibrium data and the corresponding equilibrium solid phase, the phase diagram of the ternary systems were shown, respectively. The results show that the two ternary systems at 273 K are simple total saturated type and there are no complex salt and solid solution found. Besides, the phase diagrams of the two ternary systems are both constituted of a eutectic point, two univariant solubility curves, and two solid crystalline phase regions. The two equilibrium solid phases corresponding to the eutectic point of the Li2B4O7-MgB4O7-H2O ternary system are Li2B4O7·3H2O and MgB4O7·9H2O. In the K2B4O7-MgB4O7-H2O ternary system, K2B4O7·4H2O and MgB4O7·9H2O are the two equilibrium solid phases relevant to the eutectic point. Furthermore, the experimental results of densities were simply discussed, and the phase diagrams at different temperatures were compared. © 2016 American Chemical Society.

Chen S.-H.,Chengdu University of Technology | Chen S.-H.,Sichuan Higher Education Institutions | Zhang D.-F.,Chengdu University of Technology | Sun G.,Chengdu University of Technology
Materials Letters | Year: 2014

New porous ceramics with a framework structure of magnesium borate (Mg 2B2O5) whiskers with the diameter of 0.3-0.4 μm and length of 2-5 μm were synthesized in situ by use of [(MgCO 3)4·Mg (OH)2·5H2O] (BMC)-H3BO3 mixture at 900 C. With the addition of Ni(NO3)2, the diameter and length of Mg2B 2O5 whiskers decreased to 0.2-0.3 μm and increased to 4-8 μm, respectively, while the strength of porous ceramics increased from 4.72 to 15.72 MPa. The formation mechanism of the Mg2B 2O5 whiskers is considered to be the solution-liquid-solid (SLS) growth. © 2014 Elsevier B.V.

Shu C.,Sichuan Higher Education Institutions | Shu C.,Chengdu University of Technology | Long J.,Chengdu University of Technology | Li S.,Chengdu University of Technology | Yang W.,Chengdu University of Technology
Journal of Alloys and Compounds | Year: 2015

The lattice parameters, electronic structures, elastic constants, Vicker's hardness and thermodynamics properties of SrAuSi3 were systematically investigated by using first-principles and the quasi-harmonic Debye model. The calculated lattice parameters are in excellent agreement with the experimental data. The calculated elastic constants Cij reveal that SrAuSi3 is mechanically stable but anisotropic. The elastic anisotropy is further illustrated by the three-dimensional (3D) of bulk modulus and Young's modulus. The polycrystalline elastic modulus: shear modulus, Young's modulus, Poisson's ratio are derived from the obtained single-crystal elastic constants. In addition, the temperature dependence of the expansion coefficient, specific heat and Debye temperature are investigated through the quasiharmonic Debye model. Finally, Using the McMillan formula the Tc ∼ 9.94 K, which is conflicts with the experimental data (1.54 K). Presumably, the Tc suppression phenomenon due to the presence of an antisymmetric spin-orbit coupling (ASOC) as a consequence of the lack of inversion symmetry. © 2015 Elsevier B.V.

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