Phase equilibria relations in the V_(2)O_(5)-rich part of the Fe_(2)O_(3-)TiO_(2)-V_(2)O_(5) system at 1200℃ related to converter vanadium-bearing slag

The efficient recycling of vanadium from converter vanadium-bearing slag is highly significant for sustainable development and circular economy.The key to developing novel processes and improving traditional routes lies in the thermodynamic data.In this study,the equilibrium phase relations for the Fe_(2)O_(3)-TiO_(2)-V_(2)O_(5)system at 1200℃in air were investigated using a high-temperature equilibrium-quenching technique,followed by analysis using scanning electron microscopy-energy dispersive X-ray spectrometer and X-ray photoelectron spectroscopy.One liquid-phase region,two two-phase regions(liquid-rutile and liquid-ferropseudobrookite),and one three-phase region(liquid-rutile-ferropseudobrookite)were determined.The variation in the TiO_(2)and V_(2)O_(5)contents with the Fe_(2)O_(3)content was examined for rutile and ferropseudobrookite solid solutions.However,on further comparison with the predictions of FactSage 8.1,significant discrepancies were identified,highlighting that greater attention must be paid to updating the current thermodynamic database related to vanadium-bearing slag systems.

Measurement and Correlation of Liquid-liquid Equilibria for 1-Hexene-n-Hexane-3-Methysulfolane

Utilizing solvent extraction to separate alkanes and olefins from catalytic light gasoline is an effective method for maximizing the utility of gasoline fractions.This study presents the determination of liquid-liquid equilibrium data for the ternary system of 1-hexene-n-hexane-3-methylsulfolane at 30℃,40℃,and 50℃under atmospheric pressure.The obtained data facilitated the construction of a ternary phase diagram for the system.The results showed that the extraction selectivity of 1-hexene/n-hexane exceeded 1.5 when using 3-methylsulfolane as the extraction solvent.Furthermore,the thermodynamic consistency of the experimental data was examined using Hand’s equation and the Othmer-Tobias method.The correlation coefficient,R^(2)≥0.9578,indicated the acceptable reliability of the phase equilibrium data.Subsequently,the NRTL(non-random two liquid)model was used to correlate the liquid-liquid phase equilibrium data and derive the binary interaction parameter.Notably,the results demonstrated that the root mean square deviation of the NRTL model correlation values from the experimental values did not exceed 2.5%.

Solid-state NMR studies of proteins in condensed phases

Some proteins perform their biological functions by changing their material states through liquid-liquid phase separation.Upon phase separation,the protein condenses into a concentrated liquid phase and sometimes into a gel phase,changing its dynamic properties and intermolecular interactions,thereby regulating cellular functions.Although the biological significance of this phenomenon has been widely recognized by researchers,there is still a lack of a comprehensive understanding of the structural and dynamic properties of the protein in the condensed phase.In this phase,molecules usually contain domains with varied dynamic properties and undergo intermediate exchanges.Magic angle spinning(MAS)solid-state NMR(SSNMR)experiments are very powerful in studying rigid protein polymers such as amyloid.The incorporation of solution-like experiments into SSNMR and the development of J-coupling based MAS SSNMR techniques extend its ability to study partially mobile segments of proteins in a condensed liquid or gel phase which are not visible by solution NMR or dipolar-coupling based SSNMR.Therefore,it has been applied in studying protein condensation and has provided very important information that is hard to obtain by other techniques.

Effect of the interaction between the chemical and the magnetic ordering on the phase equilibria of iron base alloys

It is well known that the magnetic properties such as the Curie temperature Tmag <sub>C and the mean magnetic moment β of ordered compounds have different values from those of the disordered solutions. For instance, both Tmag c and β of the Ni3Pt （L12） and NiPt （L10） and Tmag <sub>c of the CoPt （L10） and CoPt3 （L12） ordered compounds are strongly depressed due to the ordering compared with those of the metastable disordered Ni-Pt and Co-Pt alloys. On the other hand, the γ’-FeNi3 （L12） and the α’-FeCo （B2） ordered compounds have higher Tmag <sub>c and β values comparing with the disordered solution phases, γ （A1） and α （A2）, respectively. In consequence, the stability of the ordered phase is depressed or enhanced due to the interaction between the chemical and magnetic ordering caused by the decrease or increase of Tmag <sub>c and β values. The purpose of this study is to investigate the effect of the interaction between the chemical and the magnetic ordering on the phase equilibria in the Fe-X（X=Al, Co, Ni, Rh, Si） binary systems.The Gibbs energy of the α（A2）, γ（A1） and liquid phases is described by a sub-regular solution approximation. The ordering contribution to the Gibbs energy ,ΔGorder <sub>m, and deviations of magnetic properties, ΔTmag <sub>c and Δβ, of the ordered compounds, FeAl （B2）, Fe3Al （D03）, FeCo （B2）, FeRh （B2）, FeSi （B2）, Fe3Si （D03） and FeNi3 （L12） is introduced by the split compound energy formalism. Effect of the interaction between the chemical ordering, B2, D03 and L12 and the magnetic ordering on the phase equilibria will be discussed according to the calculated phase diagrams of the Fe-X binary systems.

Liquid-Solid Phase Equilibria of Nb-Si-Ti Ternary Alloys

To determine the liquid-solid phase equilibria of the Nb-Si-Ti ternary system, Nb-Si-Ti alloys of different compositions are prepared. By means of scanning electron microscopy （SEM）, X-ray diffraction （XRD） and electron probe microanalysis （EPMA）, the phases in the alloys, such as Si-based solutions, Ti（Nb）Si, Ti（Nb）Si2, Nb（Ti）Si2, Ti（Nb）5Si4, Nb（Ti）5Si3, Ti（Nb）5Si3, Nb（Ti）3Si and Nb-based solutions are identified, and the phase evolution is analyzed. As a result, the microstmctural and microchemical evidence provides a clear definition of the Nb-Si-Ti liquidus surface projection and indicates that the ternary phase diagram has seven transition reactions.

Phase equilibria for the pseudo-ternary system(NaCl+Na2SO4+H2O)of coal gasification wastewater at T=(268.15 to 373.15)K

The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal solution saturation method. The equilibrium solids were also investigated by the Schreinemaker's method of wet residues and X-ray powder diffraction(XRD). According to the experimental data, the phase diagrams were determined. It was found that there was no significant solubility difference on the Na Cl-rich side between the ternary system(Na Cl + Na_2SO_4+ H_2O) in coal gasification wastewater and in pure water. However, the solubility on the Na_2SO_4-rich side of coal gasification wastewater was apparently higher than that of pure water. The increase in the solubility of Na_2SO_4 was most likely caused by the effects of other impurities apart from Na Cl and Na_2SO_4 in coal gasification wastewater. The measured data and phase equilibrium diagrams can provide fundamental basis for salt recovery in coal gasification wastewater.

Modeling phase equilibria of semiclathrate hydrates of CH_4,CO_2 and N_2 in aqueous solution of tetra-n-butyl ammonium bromide

Semiclathrate hydrates of tetra-n-butyl ammonium bromide （TBAB） offer potential solution for gas storage, transportation, separation of flue gases and CO2 sequestration. Models for phase equilibria for these systems have not yet been developed in open literatures and thus require urgent attention. In this work, the first attempt has been made to model phase equilibria of semiclathrate hydrates of CH4, CO2 and N2 in aqueous solution of TBAB. A thermodynamic model for gas hydrate system as proposed by Chen and Guo has been extended for semiclathrate hydrates of gases in aqueous solution of TBAB. A correlation for the activity of water relating to the system temperature, concentration of TBAB in the system and the nature of guest gas molecule has been proposed. The model results have been validated against available experimental data on phase equilibria of semiclathrate hydrate systems of aqueous TBAB with different gases as guest molecule. The extended Chen and Guo＇s model is found to be suitable to explain the promotion effect of TBAB for the studied gaseous system such as, methane, carbon dioxide and nitrogen as a guest molecule. Additionally, a correlation for the increase in equilibrium formation temperature （hydrate promotion temperature, ATp） of semiclathrate hydrate system with respect to pure gas hydrate system has been developed and applied to semiclathrate hydrate of TBAB with several gases as guest molecules. The developed correlation is found to predict the promotion effect satisfactorily for the system studied.

Stable and metastable phase equilibria in binary Mg-Gd system: A comprehensive understanding aided by CALPHAD modeling

In this paper,a comprehensive understanding of stable and metastable phase equilibria in binary Mg-Gd system was conducted with an aid of the CALculation of PHAse Diagram(CALPHAD)modeling.Firstly,thermodynamic descriptions of all the stable phases in the Mg-Gd system were re-assessed by considering all the experimental data in the literature.The discrepancy between the phase equilibria and thermochemical properties existing in the previous assessments was eliminated,and the better agreement with the experimental data was achieved in the present assessment.Secondly,the Gibbs energies for metastable β"-Mg3Gd and β"-Mg7Gd were constructed based on the first-principles and CALPHAD computed results as well as their correlation,and then incorporated into the CALPHAD descriptions.The model-predicted solvuses of(Mg)in equilibrium with the metastable β"-Mg7Gd and β'-Mg7Gd compounds showed very good agreement with the limited experimental data.Finally,the presently obtained thermodynamic descriptions of both stable and metastable phases in the binary Mg-Gd system were further validated by realizing the quantitative Scheil-Gulliver solidification simulations of 5 as-cast Mg-Gd alloys,and the successful prediction of the precipitation sequences in Mg-15Gd and Mg-12Gd alloys during the aging process.

Phase Equilibria in Nb-Si-Mo Ternary Alloys at 1273 K and 2073 K

Phase equilibrium in Nb-Si-Mo ternary alloys （〈37.5 at.% Si） at 1 273 K and 2 073 K is investigated by using X-ray diffraction （XRD） analysis, scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）. The partial isothermal section at 1 273 K, which contains four single-phase regions, five two-phase regions and two three-phase regions, is basically the same as that at 1 973 K. However, when the temperature increases to 2 073 K, the three-phase region of Nbss＋ct-（Nb（Mo））sSi3＋13-（Nb,Mo）sSi3 obviously moves towards the Nb-rich comer. This suggests that Nb-Si-Mo ternary alloys remain stable at least up to 1 973 K.

Calculation of Phase Equilibria Based on the Levenberg-Marquardt Method

The Levenberg-Marquardt method, the best algorithm to obtain the least-square solution of nonlinear equations, is applied to calculate the stable phase equilibria. It can get the best combination between robustness and speed of the calculations. Its application to ternary AI-Si-Mg system is executed in detail. The calculated phase equilibria agree well with the experimental results. Furthermore, the Levenberg-Marquardt method is not sensitive to the initial values.

Effect of CaO/SiO_2 and Fe/SiO_2 ratios on phase equilibria in PbO-ZnO-CaO-SiO_2-“Fe_2O_3” system in air

Experimental studies on phase equilibria and liquidus temperature in the PbO-ZnO-CaO-SiO2-＂Fe2O3＂ system,with the mass ratios of CaO/SiO2=1-1.6 and Fe/SiO2= 1.3-1.7,and 40% PbO and 8% ZnO,were carried out between 1273 and 1573 K.Slags were equilibrated at 1273 to 1573 K and cooled rapidly by quenching.The XRD and SEM-EDS results showed that the slag compositions are in the franklinite primary phase field.Calcium and lead silicates are formed between 1373 and 1473 K.The Ca/Pb silicate and magnetoplumbite phases are partially formed by an incongruent reaction.The experimental and thermodynamical results showed that the liquidus increased by increasing CaO/SiO2 mass ratio and decreasing Fe/SiO2 mass ratio.

Measurement of phase equilibria in Ti-Ni-Sn system

Phase relations of the Ti-Ni-Sn ternary system were investigated via alloy sampling assisted with X-ray diffractometry(XRD)and electron probe micro-analysis(EPMA).A new binary phase with composition of TiSn4(molar fraction,%)was detected at 508 K.In addition,a supplementary phase(Ti1-x-yNixSny)Ni3(τ,AuCu3-type)was observed at 873 and 973 K.According to the characterised microscopic structure in various annealed alloys,four ternary phases were detected in Ti-Ni-Sn ternary system:TiNiSn,TiNi2Sn,Ti2Ni2Sn and(Ti1-x-yNixSny)Ni3.Additionally,isothermal sections of Ti-Ni-Sn ternary system at 508,873 and 973 K were constructed.By comparing three isothermal sections,a peri-eutectic reaction,L+TiNi2Sn→Ni3Sn4+TiNiSn,was deduced,which occurs at a temperature between 873 and 973 K.Furthermore,the solubility of Sn in TiNi and Ni in Ti5Sn3 was detected.

Thermodynamics and Phase Equilibria for Ce,Y in the Presence of O,S in Ni-base Solutions

The deoxidation,desulfuration,deoxysulfuration constants and the standard Gibbs energies(in J mol^(-1))of formation of the following rare earth compounds as the equilibrium phases in Ni-base solutions are given: Ce_2O_3:lgK=-(6.0729×10~4/T)+16.50 △G^0=-1.162460×10~6+315.84T Ce_2O_2S:lgK=-(5.1450×10~4/T)+12.46 △G^0=-9.84850×10~5+238.50T Ce_2S_3:lgK=-(7.2232×10~4/T)+27.98 △G^0=-1.382600×10~6+535.55T Y_2O_3:lgK=-(4.2572×10~4/T)+7.74 △G^0=-8.14920×10~5+148.16T Y_2O_2S:lgK=-(3.3146×10~4/T)+3.85 △G^0=-6.34460×10~5+73.72T Y_2S_3:lgK=-(1.22487×10~5/T)+55.78 △G^0=-2.344630×10~0+1067.76T Interaction coefficients between Ce.Y and O are also given: e_o^(?)=-(3.33451×10~5/T)+149.7 e_O^(?)=-(1.63437×10~5/T)+71.8 The phase equilibria for Ni-Ce-S-O and Ni-Y-S-O solutions at 1600℃ provide the basis for pre- dicting the sequence and type of Ce and Y equilibrium phases formed in Ni-base solutions.The formulas controlling the morphology of inclusion formed in liquid Ni by Ce or Y addition are also given.

PHASE EQUILIBRIA OF α_2(α)/γ IN Ti-Al-Nb TERNARY SYSTEM

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Liquid-Liquid Equilibria of Water + Butyric Acid + Nonanol Ternary System

Liquid-liquid equilibrium (LLE) data for the water + butyric acid + nonanol system have been determined experimentally at the temperatures of 298.15 K, 308.15 K and 318.15 K. Tie-line compositions were correlated by Othmer-Tobias method. The universal quasichemical functional group activity coefficient (UNIFAC) and modified UNIFAC methods were used to predict the phase equilibrium in the system using the interaction parameters between CH3, CH2, COOH, OH and H2O functional groups. Distribution coefficients and separation factors were evaluated for the immiscibility region.

Liquid-Liquid Equilibria of the Water-Ethanol-Dimethyl Succinate Ternary System

Liquid-liquid equilibrium (LLE) data for the ternary systemwater-ethanol-dimethyl succinate have been determined experimentallyat temperatures ranging from 298.15 to 318.15 K at 5 K intervals.Complete phase diagrams were obtained by determining solubility andthe tie-line data. Tie-line compositions were correlated byOthmer-Tobias method. The universal quasichemical functional groupactivity coefficient (UNIFAC) and modified UNIFAC methods were usedto predict the phase equilibrium in the system using the interactionparameters deter- Mined from experimental data between groups CH_3,CH_2, OH, CH_3 COO and H_2O.

Phase Equilibria of the Aqueous Systems Containing Lithium and Carbonate Ions

1 Introduction Alkaline lakes are widely distributed in the area of the Qinghai-Tibet Plateau.Most of the salt lakes are famous for their high concentration of lithium,potassium,magnesium,boron(Ma,2000).In recent years,as a new energy material,lithium and its compounds are widely used in the new area,such as aerospace industry,nuclear

DETERMINATION OF PHASE EQUILIBRIA AND CRITICAL LOCUS OF CO_2-HCFC22 SYSTEM

1 INTRODUCTIONHydrochlorofluorocarbons(HCFCs)and hydrofluorocarbons(HFCs)are alternatives tochlorofluorocarbons(CFCs),such as CFC12(freon 12),which has been widely used asan aerosol agent and working fluid of domestic1:ICthdflC(CHCIFZ,HCFC22,R22)is one of the potential alternatives.It Is also one of the po-tentlal entralner for supercrltlcal fluid CO,extraction.

EXPERIMENTAL MEASUREMENT OF SUPERCRITICAL CO_2-LOW VOLATILITY LIQUID PHASE EQUILIBRIA

Extraction equilibria of three low volatility liquids （benzyl alcohol,2-phenethyl alcohol and citronellol）separately with supercritical CO2 were determined in a semi-flow apparatus at two temperatures（308.2K and318.2K）and pressures up to 20MPa.The solubility data of CO2 in methyl benzoate were also obtained at thetwo temperatures in two-phase region.The experimental data were correlated by means of the Peng-Robinsonequation of state with two characteristic parameters.

Thermodynamics Phase Equilibria for the Salt- Water System of Potassium and Rubidium Ions

1 Introduction Brines,containing a variety of useful components,such as alkali metal(IA),alkaline earth metal(type IIA),halogen elements(such as VIIA),are naturally occurring complex electrolyte solution.Although rubidium is not the main component of the brine,while in the brine exploiting process,rubidium ion is continuously enriched in the