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Investigation of Surface Tensions for Pure Fluids outside and inside the Critical Region

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Chinese Journal of Chemistry 2006年第10期24卷 1315-1320页

作者：付东 School of Environmental Science and Engineering North China Electric Power University Baoding Hebei 071003 China

An equation of state （EOS） applicable for both the uniform and non-uniform fluids was established by using the density-gradient expansion, in which the influence parameter x[ρ（r）,T] was obtained by the use of direct correlation function. The density functional theory （DFT） provides a framework under which both the phase equilibria and interfacial properties can be investigated within a single set of molecular parameters. The phase equilibria inside the critical region can be improved by the renormalization group theory （RGT）. However, the correction of interfacial properties by DFT and RGT is computationally difficult. In the present work, the density gradient theory （DGT） in which κ[ρ（r）,T] is treated as a constant is used to combine with the RGT for interfacial properties inside the critical region.

关键词： critical region phase equilibrium surface tension renormalization group theory density functional theory density gradient theory

Measurements and Calculations of Solid-liquid Equilibria in Quaternary System Li2SO4-Na2SO4-K2SO4-H2O at 288 K

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Chemical Research in Chinese Universities 2017年第3期33卷 460-465页

作者： CUI Ruizhi YANG Lei WANG Wei SANG Shihua College of Materials and Chemistry & Chemical Engineering Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institutions Chengdu University of Technology Chengdu 610059 P. R. China

The isothermal dissolution equilibrium method has been used to investigate the solid and liquid equilibria of quatemary system Li2SO4-Na2SO4-K2SO4-H2O at 288 K. The phase diagram and water diagram were plotted according to the experiment results. It was found that LizSO4-Na2SO4-K2SO4-H2O quaternary system contains four double salts at 288 K. There are six invariant points, twelve univariant curves and seven areas of crystallization： Li2SO4·H2O, Na2SO4·10H2O, K2SO4,LiESO4·3Na2SO4-12H2O, Li2SO4K2SO4, Na2SO4·3K2SO4, 2Li2SO4·Na2SO4- K2SO4. Using the equilibrium solubility data of the quaternary system at 288 K, the solubility product（lnKsp） of solid phase ***4, which is not reported was acquired. Based on the chemical model of Pitzer＇s electrolyte solution theory, the solubilities for the quaternary system Li2SO4-Na2SO4-K2SO4-H2O at 288 K were calculated with corresponding parameters. Compared the results of experimental measurement with those of calculation, it was shown that the calculated values had a good agreement with the experimental ones.

关键词： Salt-water system phase equilibrium Solubility Sulfate Pitzer's equation

ISOTHERMAL SECTION OF Mg-Zn-La SYSTEM IN Mg RICH CORNER AT 350℃

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Acta Metallurgica Sinica(English Letters) 2008年第5期21卷 329-335页

作者： M.L. Huang H.X. Li H. Ding Y.P. Ren S.M. Hao School of Materials and Metallurgy Northeastern University Shenyang 110004 China

Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy （SEM）, electron probe microanalysis with energy dispersive X-ray spectroscopy （EPMA-EDS）, and X-ray diffraction （XRD） have been used to identify the phase equilibrium and the composition of each phase in the alloys. As a result, the isothermal section of Mg-Zn-La system in Mg rich corner at 350℃ has been determined. The result shows that, in addition to some binary phases, there exists a linear ternary compound called T-phase in Mg-Zn-La system at 350℃, in which the La content is about 8 at. pct ±0.4 at. pct and the Zn content is 8 at. pct- 48 at. pct. The T-phase has a C-centered orthorhombic crystal structure, and the lattice parameters are a=0.965-1.020 nm, b=1.121 1.142 nm, c=0.950-0.977 nm.

关键词： Mg-Zn-La system phase equilibrium T-phase Isothermal section

phase Equilibria of Hornblende-Bearing Eclogite in the Western Dabie Mountain,Central China

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Acta Geologica Sinica(English Edition) 2009年第1期83卷 57-69页

作者： ZHANG Jingsen WEI Chunjing LOU Yuxing SU Xiangli Hebei University of Engineering Handan Hebei 056038 China Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education School of Earth and Space Sciences Peking University Beijing 100871 China

The high-pressure （HP） eclogite in the western Dabie Mountain encloses numerous hornblendes, mostly barroisite. Opinions on the peak metamorphic P-T condition, PT path and mineral paragenesis of it are still in dispute. Generally, HP eclogite involves garnet, omphacite, hornblendes and quartz, with or without glaucophane, zoisite and phengite. The garnet has compositional zoning with XMg increase, XCa and XMn decrease from core to rim, which indicates a progressive metamorphism. The phase equilibria of the HP eclogite modeled by the P-T pseudosection method developed recently showed the following：（1） the growth zonation of garnet records a progressive metamorphic PT path from pre-peak condition of 1.9-2.1 GPa at 508~C-514~C to a peak one of 2.3-2.5 GPa at 528~C-531~C for the HP eclogite; （2） the peak mineral assemblage is garnet＋omphacite＋glaucophane＋quartz_＋phengite, likely paragenetic with lawsonite; （3） the extensive hornblendes derive mainly from glaucophane, partial omphacite and even a little garnet due to the decompression with some heating during the post-peak stage, mostly representing the conditions of about 1.4-1.6 GPa and 580~C-640~C, and their growth is favored by the dehydration of lawsonite into zoisite or epidote, but most of the garnet, omphacite or phengite in the HP eclogite still preserve their compositions at peak condition, and they are not obviously equilibrious with the hornblendes.

关键词： eclogite hornblende peak P-T condition phase equilibrium PT path western Dabie Mountain

Experimental Binary phase Diagram of Bilayer Compounds [n-CnH2n＋1N（CH3）3]2CoCl4

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Chemical Research in Chinese Universities 2015年第4期31卷 611-614页

作者： WU Kezhong SUN Xiaolong RUAN Bei XIONG Yuanyuan CHEN Jing Department of Chemistry and Material Science Hebei Normal University Shijiazhuang 050024 P tL China

Compounds [n-CnH2n＋1N（CHs）3]2CoCl4（n=16, C46C3Co; n=18, C18C3Co） containing lipid-like bilayers embedded in a crystalline matrix exist in solid-solid phase transition. The low-temperature bilayer structures of the two compounds were organized by neutralizing CoCl24- with alkylammonium ions. Alkyl chains lay parallel to each other and slightly tilted with respect to the normal of the inorganic layers. The adjacent alkyl chains interacted with each other by van der Waals interaction. When the temperature increased, the two compounds underwent a reversible solid-solid phase transformation within 310-330 K. In such a case, the chains showed a large motional freedom, and a disordered phase appeared. The structures can alternatively be viewed as a double layer of alkylammonium ions between COCl24- sheets and be considered as crystalline models of lipid bilayers. The experimental subsolidus binary phase diagram of [n-C16H33N（CH3）3]2CoCl4-[n-C18H37N（CH3）3]2CoCl4 was constructed over the entire composition range by differential scanning calorimetry and X-ray diffraction technique. Experimental phase diagram indicates one stable intermediate phase [n-C16H33N（CH3）3][n-C18H37N（CH3）3]CoCl4 at wC16C3Co = 39.89% and two invariant three-phase equilibria, which shows two eutectoid temperatures： Te1 at （316±1） K for WC16C3Co=27.35% and Te2 at （313±1）K for Wc16c3co =59.76%. These three noticeable solid-solution ranges are a-phase at the left, β-phase at the right, and γ-phase in the middle of the phase diagram.

关键词： Quaternary ammonium tetrachlorometallate Differential scanning calorimetry Eutectoid temperature phase equilibrium phase diagram

Effect of Oxygen Partial Pressure on phase Equilibria and Liquidus in CaO-Al_2O_3-FeO_x System

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Journal of Iron and Steel Research(International) 2012年第11期19卷 8-12页

作者： WANG Nan HUANG Wei-jun CHEN Shuai-chao CHEN Min School of Materials and Metallurgy Northeastern University Shenyang 110819 Liaoning China

A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pres- sure on the phase equilibria and liquidus in CaO-Al2O3- FeOx system with the intermediate oxygen partial pressures of 10.13 Pa and 1.01 × 10^-3 Pa. The equilibrated phases and their compositions of the quenched samples were analyzed by using SEM/EPMA （Scanning Electron Microscope/Electron Probe Micro Analysis） and XRD （X Ray Diffraction）. The phase equilibrium results include two cases, the two phase coexistence and the three-phase coexistence in the high Al2O3 region with oxygen partial pressure of either 10.13 Pa or 1.01 × 10^-3 Pa. Effects of oxygen partial pressure and temperature on the liquidus along the primary phase fields of CaO · Al2O3 and CaO · 2Al2O3 were nota hle. With the decrease of oxygen partial pressure, the liquid area expands and the liquidus of CaO · Al2O3 and CaO · 2Al2O3 primary fields moves to the Al2O3-FeOx region. On the other hand, the liquid area of CaO Al2O3-FeOx sys tem extends extremely to the high Al2O3 region with the temperature increasing from 1 400 to 1 500℃, especially at lower oxygen partial pressure. The present experiment results are in good agreement with the calculated ones by FactSage.

关键词： oxygen partial pressure liquidus phase equilibrium CaO-Al2O3 FeOx system

Thermodynamic Calculation of Carbide Precipitate in Niobium Microalloyed Steels

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Journal of Iron and Steel Research(International) 2006年第6期13卷 53-56页

作者： XU Yun-bo YU Yong-mei LIU Xiang-hua WANG Guo-dong State Key Lab of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

On the basis of regular solution sublattice model, thermodynamic equilibrium of austenite/carbide in Fe-Nb-C ternary system was investigated. The equilibrium volume fraction, chemical driving force of carbide precipitates and molar fraction of niobium and carbon in solution at different temperatures were evaluated respectively. The volume fraction of precipitates increases, molar fraction of niobium dissolved in austenite decreases and molar fraction of carbon increases with decreasing the niobium content. The driving force increases with the decrease of temperature, and then comes to be stable at relatively low temperatures. The predicted ratio of carbon in precipitates is in good agreement with the measured one.

关键词： microalloyed steel thermodynamic calculation phase equilibrium carbide prediction model

phase Equilibria of Quaternary System NaCl-NaBr-Na2B4O7-H2O at 348 K

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Chemical Research in Chinese Universities 2013年第2期29卷 311-313页

作者： LI Ting SANG Shi-hua CUI Rui-zhi ZHANG Kai-jie College of Materials and Chemistry & Chemical Engineering Chengdu University of Technology Chengdu 610059 P. R. China Mineral Resources Chemistry Key Laboratory of Siehuan Higher Education Institutions Chengdu 610059 P. R. China

The phase equilibria of quaternary system NaCl-NaBr-Na2B4O7-H2O at 348 K were studied by the iso- thermal equilibrium method. The solubilities and densities of the equilibrium solution were determined. According to the experimental data, the phase diagram, density-composition diagrams and water content diagram of the quaternary system at 348 K were plotted respectively. And the phase diagram consists of one univariant curve, two crystalliza- tion fields and without any invariant point of the quaternary system. The equilibrium solid phases of the two crysta- llization fields were Na（C1, Br） and Na2B4OT＇5H20, The experimental results show that the quaternary system contained solid solution. The densities of the solution decrease with increasing NaC1 concentration and increase with increasing NaBr concentration.

关键词： Solid solution phase equilibrium Solubility Salt-water system

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

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Chemical Research in Chinese Universities 2018年第5期34卷 803-807页

作者： LI Dongchan FAN Rong YANG Sennan ZHANG Ziyi College of Chemical Engineering and Technology Hebei University of Technology Tianjin 300130 P. R. China Engineering Research Center of Seawater Utilization Technology JkIinistry of Education Hebei University of Technology Tianjin 300130 R R. China

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 equilibritma 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 NaC1 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.

关键词： phase equilibrium Solubility phase diagram Oilfield brine