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Phase equilibria studies were undertaken on the "CuO 0.5 "-PbO-CaO system in equilibrium with Cu/Pb metal as part of the integrated experimental and thermodynamic modelling study of phase equilibria in the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-O-S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co and Na) gas/oxide liquid/matte/speiss/metal/solids system in support of the development and optimisation of pyrometallurgical processes. The equilibration and quenching technique followed by the electron probe X-ray microanalysis (EPMA) was used in the present study. The primary phase fields of massicot (PbO), copper plumbite (Cu 2 PbO 2), cuprite (Cu 2 O) and lime (CaO) were experimentally characterised. The experimental data obtained in the present study, as well as available literature data on the phase equilibria and thermodynamics of the "CuO 0.5 "-PbO-CaO system in equilibrium with Cu/Pb were used for the optimisation of the model parameters of the discussed system in agreement with the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-O-S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co and Na) gas/oxide liquid/matte/speiss/metal/solids system to obtain a self-consistent set of parameters of the thermodynamic model for all phases. The predicted liquidus surface of the "CuO 0.5 "-PbO-CaO system was presented for the first time in the complete range of temperatures and compositions. [ABSTRACT FROM AUTHOR]

Adding titanium oxide has become a common practice in modern blast furnace operating procedures. The blast furnace slag is based on the CaO–MgO–Al 2 O 3 –SiO 2 –TiO 2 low titanium slag system rather than CaO–MgO–Al 2 O 3 –SiO 2 system. Phase equilibria in the CaO–SiO 2 –Al 2 O 3 –MgO–TiO 2 system in the low-TiO 2 part have been experimentally determined by means of high temperature equilibration and quenching technique followed by electron probe X-ray microanalysis. Introducing a small quantity of titanium-bearing materials can lower the liquidus temperature. The TiO 2 content in the slag should be controlled below 4.6 wt%, otherwise it will enter the perovskite phase region where the liquidus temperatures increases rapidly. The compositions of the solid solutions corresponding to the liquidus have been precisely measured and should be utilized for developing the thermodynamic database. [ABSTRACT FROM AUTHOR]

The large variability in Fe isotope ratios of sedimentary rocks (particularly those from the Archean and Proterozoic) contrasts with that of igneous rocks, which display a much more limited range in values. Notably, among igneous rocks, those inferred to form via partial melting of siliciclastic sediments – strongly peraluminous granites (SPGs) – exhibit greater variability in their Fe isotope compositions, suggesting SPGs may capture isotopic variations in the sedimentary record. However, the extent and mechanisms of iron isotope fractionation between SPGs and their source remain poorly understood. Our study integrates iron isotope analyses with petrological modeling to investigate equilibrium isotopic fractionation during generation of SPG magmas. As a case study, we focus on the Neoarchean Ghost Lake Batholith and the adjacent metasedimentary rocks in Ontario, Canada. These units represent an internally differentiated SPG batholith and metamorphosed sedimentary rocks interpreted as the source of the batholith. We measured δ56Fe compositions of SPG samples, metasedimentary rocks, and a restitic rock. Sulfide grains were also measured in four metapelite samples and a granite sample. We find no correlation between the δ56Fe composition of metasedimentary rocks and their metamorphic grade, indicating iron isotopes behave as a closed system during metamorphism. Modeling results show that iron isotopes in SPGs from the Ghost Lake batholith are consistent with equilibrium fractionation during biotite dehydration melting, with predicted δ56Fe values for melts and restitic assemblages mainly controlled by the source composition. Our results predict negligible isotopic fractionation between the residue and the source, whereas ∼0.177–0.277 ‰ is expected between SPG melts and the residue, accounting for high δ56Fe values in granite samples. Lower δ56Fe values may indicate that some granites represent mixtures of melt and cumulus material or result from assimilation of restite or source/host rock. However, despite deviations from pure equilibrium fractionation, the variability in δ56Fe values for SPGs is about one order of magnitude smaller than that seen in the sedimentary record for the Archean and Proterozoic (∼0.2 ‰ vs. >2 ‰). We posit that this narrower range of isotopic variation in SPGs results from metamorphism and partial melting, which can homogenize large isotopic variations in sedimentary protoliths. Thus, SPGs represent reliable archives for the bulk iron isotope evolution of siliciclastic sedimentary rocks through time. [ABSTRACT FROM AUTHOR]

The 1773 K phase diagram of the TiO 2 –SiO 2 –CaO-10 wt%Al 2 O 3 -7.5 wt%MgO system was constructed experimentally using the quenching method, focusing on the composition range of high TiO 2 content. The obtained isothermal section contains four phase fields: the liquid phase field, the primary phase field of pseudo-brookite, the primary phase field of perovskite, and the liquid + perovskite + pseudo-brookite phase field. The pseudo-brookite particle precipitated in its primary phase field is more suitable for the efficient selective enrichment and separation of titanium resources. The increase of MgO from 5 % to 7.5 % in the TiO 2 –CaO–SiO 2 -10 wt%Al 2 O 3 –MgO system leads to a decrease of the liquidus temperature and an expansion of the liquid + pseudo-brookite + perovskite phase field. The increase of MgO promotes the enrichment of TiO 2 into the pseudo-brookite phase and reduces the TiO 2 level in the glass phase. [ABSTRACT FROM AUTHOR]

Experimental investigation and thermodynamic modeling of the phase equilibria in the (PbO)-NiO-ZnO-SiO 2 system has been undertaken to characterize Ni behavior in high-Zn slags. Phase equilibria data at 790–1700 °C were obtained through equilibration of synthetic mixtures in sealed silica ampoules or Pt-Ir / Au foils, rapid quenching, and electron probe X-ray microanalysis. Phase equilibria and liquidus isotherms of the NiO-ZnO-SiO 2 system in the tridymite/cristobalite SiO 2 , monoxide (Ni,Zn)O, zincite (Zn,Ni)O, olivine (Ni,Zn) 2 SiO 4 and willemite (Zn,Ni) 2 SiO 4 phase fields were measured and the extent of the 2-liquid immiscibility gap over cristobalite was determined. Additional solid solutions: larsenite Pb(Zn,Ni)SiO 4 and melilite Pb 2 (Zn,Ni)Si 2 O 7 were measured in the PbO-NiO-ZnO-SiO 2 system. It was found that NiO partially substitute ZnO in larsenite and melilite and may form a complete range of solubility in barysilite Pb 8 (Zn,Ni)Si 6 O 21. New data were used for developing a thermodynamic database to describe the Pb/Cu-containing complex system for characterizing Ni behavior in Zn-containing slags. [ABSTRACT FROM AUTHOR]

The variability of the composition of recycled copper-containing materials requires enhanced control and understanding of slag chemistry in the secondary pyrometallurgical processing, when compared to primary copper smelting. In the black copper route for recycling waste electronic and electrical equipment (WEEE), slags exhibit high concentrations of alumina and zinc oxide. The simplest system governing phase equilibria at the reducing smelting stage of the black copper process is "CuO 0.5 "-ZnO-FeO-FeO 1.5 -CaO-SiO 2 -AlO 1.5. In the present study, slags within this system were equilibrated with liquid copper Cu and solid Fe metallic alloys, quenched and characterized by the Electron Probe X-ray Microanalysis (EPMA). The range of compositions was selected based on the information about the process available in literature. The study focused on the liquidus and proportion of solid spinel in the temperature range from 1100 to 1300 °C. Precise control of the proportion of solids can enhance the stability of refractory materials against corrosive slags while maintaining entrained metal droplets at reasonably low level. Additionally, experimental correlations between the solubility of copper in the oxide liquid and the partial pressure of oxygen were developed for the Zn-free slags in equilibrium with metallic copper at 1200 and 1300 °C. All experimental results were compared to thermodynamic predictions using recent models and FactSage® software. Uncertainties were identified to be used in further model improvement. [ABSTRACT FROM AUTHOR]

The phase relationships of Eu 2 O 3 - Gd 2 O 3 – ZrO 2 system at 1873 K and 1673 K were investigated. To experimentally determine the phase relationships, the scanning electron microscopy, X-ray diffraction, and electron probe microanalyzer with wavelength dispersive spectrometer were employed. Our findings indicated that there were no ternary compounds. However, the binary pyrochlore phases (Eu 2 Zr 2 O 7 and Gd 2 Zr 2 O 7) formed a continuous solid solution, denotated as (Eu 2-x Gd x)Zr 2 O 7 at 1673 K. Moreover, the solubility of Gd 2 O 3 was observed to reach at least 28.0 mol.% along Eu 2 Zr 2 O 7 - Gd 2 O 3 composition line at 1873 K. Additionally, a continuous cubic solid solution was formed between C–Gd 2 O 3 and C–Eu 2 O 3 at 1673 K. The obtained experimental data were utilized to optimize the thermodynamic parameters for the Eu 2 O 3 - Gd 2 O 3 – ZrO 2 system. Thermodynamic modeling was carried out to reproduce the present phase diagram experimental results and isothermal phase diagrams of this ternary system at 1673 and 1873 K were calculated. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the performance of the Perturbed Hard-Sphere-Chain (PHSC) equation of state (EoS) for the calculation of methane hydrate formation in the presence of ionic liquids (ILs). The van der Waals and Platteeuw model is utilized to calculate the hydrate dissociation pressure. The performance of the PHSC model is compared to cubic EoSs and the Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT) model. Two activity coefficient models are used to estimate the water activity in the presence of ILs. The results show that PHSC EoS with an activity coefficient model provides lower average error values (lower than 2%) and changing the activity coefficient models does not have a great effect on reducing the error. Also, the results of cubic-based EoSs are quite remarkable considering their simplicity. The PHSC model can be utilized as a robust and efficient thermodynamic model for hydrate dissociation pressure calculation in the presence of IL. [Display omitted] • The hydrate dissociation pressure modeling in the presence of ionic liquids is studied. • The effect of the activity coefficient model on hydrate dissociation conditions is addressed. • A simple approach based on the cubic EoS shows acceptable results. • The PHSC model can be used if the minimum error is desired. [ABSTRACT FROM AUTHOR]

Thermodynamic investigation of the Na 2 O–Al 2 O 3 –CaO system plays an important role in the applications of HACs and refractory. However, the phase relationships in the Al 2 O 3 -rich corner of the isothermal section at 1473 K for this system are uncertain. Key experimental investigation was performed and an improved method was developed to prepare the samples. Four three-phase regions of NC3A8+CA2+β-Al 2 O 3 , CA2+CA6+β-Al 2 O 3 , CA6+β-Al 2 O 3 +Al 2 O 3 and NC3A8+NA6+β-Al 2 O 3 were confirmed by X-ray diffraction. The Na 2 O–Al 2 O 3 system was reassessed by CALPHAD method and the Na 2 O–Al 2 O 3 –CaO system was optimized by using the ionic two-sublattice liquid model (Na+1,Al+3,Ca+2) P (AlO 2 −1,O−2) Q to describe the liquid phase and a sublattice compound energy formalism model (Na+1) 2 (Ca+2,Na+1) 1 (Al+3) 4 (O−2) 8 (Va,Na+1) 1 to describe the ternary compound NCA2. A set of self-consistent thermodynamic parameters was finally obtained, satisfactorily reproducing the experimental data and predicting the liquidus projection and primary phase regions. The present thermodynamic investigation of the Na 2 O–Al 2 O 3 –CaO system contributes to compositional design in HACs and refractory. [ABSTRACT FROM AUTHOR]

Phase equilibria in the ZrO 2 -GdO 1.5 -TaO 2.5 (ZGTO) system are experimentally investigated, and the differences between ZGTO and the existing ZrO 2 -YO 1.5 -TaO 2.5 (ZYTO) are discussed. On Gd:Ta> 1 side, binary fluorite Gd 3 TaO 7 is measured to be stable at 1500 °C, and ternary fluorite phase forms continuous solid solution from binary ZrO 2 -GdO 1.5 to GdO 1.5 -TaO 2.5. On Gd:Ta< 1 side, there is a large difference between ZGTO and ZYTO. Firstly, GdTa 7 O 19 is unstable at 1500 °C, and GdTa 3 O 9 shows large ZrO 2 solubility and extends along Gd 1/4 Ta 3/4 O 9/4 -ZrO 2 connecting line without introducing vacancies. Secondly, non-transformable tetragonal ZrO 2 and GdTaO 4 are in equilibrium with GdTa 3 O 9 in ZGTO. Thirdly, the tetragonal ZrO 2 in equilibrium with Ta 2 Zr 6 O 17 and GdTa 3 O 9 is transformable and has lower stabilizer content. For ZrO 2 -GdTaO 4 section, tetragonal ZrO 2 and GdTaO 4 extend nearly along with Gd:Ta= 1 and exhibit smaller solubilities. This study is useful for thermodynamic assessment of ZGTO, and can help guide the design of novel thermal barrier coatings materials. [ABSTRACT FROM AUTHOR]

An integrated experimental and thermodynamic modelling investigation of the phase equilibria in the ZnO-MgO-SiO 2 and PbO-ZnO-MgO-SiO 2 systems in air has been undertaken for characterizing the effect of Zn on MgO-based refractory – slag interactions in the lead processing reactors. New experimental phase equilibria and liquidus data at 725–1740 °C were obtained using high-temperature equilibration of oxide powder mixtures followed by rapid quenching of the samples. Electron probe X-ray microanalysis was used to determine the compositions of the phases present at equilibrium conditions. Wide ranges of solid solutions were identified for periclase (Mg,Zn)O, zincite (Zn,Mg)O, olivine (Mg,Zn) 2 SiO 4 , willemite (Zn,Mg) 2 SiO 4 , pyroxene (Mg,Zn)SiO 3 , larsenite Pb(Zn,Mg)SiO 4 , barysilite Pb 8 (Zn,Mg)Si 6 O 21 and melilite Pb 2 (Zn,Mg)Si 2 O 7 phases, indicating possible stabilization of refractories in the presence of ZnO in slag. The experimental results were used for optimization of the parameters in a thermodynamic database that is subsequently used to describe the Pb/Cu-containing multi-component multi-phase system for characterizing slag-refractory interactions. [ABSTRACT FROM AUTHOR]

Phase equilibria in the ZrO 2 -Ta 2 O 5 system were studied in the temperature range from 1673 K to 1973 K using equilibration technique and in the temperature range up to 2473 K using differential thermal analysis (DTA). Phase and chemical composition of the samples was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-Ray analysis (EDX). Melting relations were studied using DTA followed by microstructure investigation by means of SEM/EDX. The eutectic reaction was determined at 1994 K and composition of 51 ± 2 mol% Ta 2 O 5. It was found that the intermediate compound Zr 6 Ta 2 O 17 melts by peritectic reaction at 2166 K. The heat capacity of this compound was measured using differential scanning calorimetry (DSC) in three temperature ranges from 100 K to 230 K, from 220 K to 570 K and from 330 K to 1295 K. Based on the obtained results and literature data thermodynamic parameters of the quasibinary ZrO 2 -Ta 2 O 5 system were optimized using the CALPHAD approach. [ABSTRACT FROM AUTHOR]

CaO solubility in the FeO t -SiO 2 -CaO-Al 2 O 3 -(ZnO, Cr 2 O 3) system has been experimentally investigated at 1200 and 1250 °C under pO 2 of 10−10 atm. Synthetic slags rich in CaO were equilibrated at desired temperatures, followed by water quenching, and analyzed using electron probe X-ray microanalysis (EPMA). In the quaternary FeO t -SiO 2 -CaO-(6 to 10 wt%) Al 2 O 3 system, CaO solubility exhibits a linear increase from 27.5 to 36.9 wt% with decreasing the FeO/SiO 2 (F/S) ratio from 1.66 to 0.62 at 1250 °C. Similarly, at 1200 °C, the CaO solubility increases from 24.9 to 30.8 wt% as the F/S ratio drops from 1.25 to 0.56. Excessive CaO addition to the slags results in the precipitation of melilite phase. Wustite is observed in the F/S ratio range of 1.66 to 1.0, and the size of wustite particles decreases as the F/S ratio decreases. At both 1200 and 1250 °C, the liquid phase with an F/S ratio below 0.42 is in equilibrium with wollastonite (CaSiO 3) in the FeO t -SiO 2 -CaO-Al 2 O 3 system. The addition of a small amount of ZnO (0.4–1.1 wt%) in the slags leads to a slight decrease in CaO solubility by 1–3 wt%, while the presence of 3.3–8.1 wt% of ZnO in the slags results in a decrease of 5–11 wt% in CaO solubility. Similar to the FeO t -SiO 2 -CaO-Al 2 O 3 system, the equilibrated CaO-containing solid phase is also melilite in the FeO t -SiO 2 -CaO-Al 2 O 3 -ZnO system. With the addition of a small amount of Cr 2 O 3 (1.0 wt%) to the FeO t -SiO 2 -CaO-Al 2 O 3 -ZnO system, spinel and dicalcium silicate (Ca 2 SiO 4) precipitate from the liquid slag, and the dissolved CaO concentration in liquid slag increases by 1–3.6 wt% in the F/S ratio range of 1.58 to 0.84, compared to the Cr 2 O 3 -free system. [ABSTRACT FROM AUTHOR]

Phase equilibria in the TiO 2 –Nb 2 O 5 system has been investigated by using the high-speed pyrometer, scanning electron microscopy and X-ray powder diffraction. The liquidus temperatures in the whole composition region are determined by cooling trace tests. Combining with the observation of solidification structure, liquidus at the TiO 2 -rich corner are clarified and the eutectic composition of Liquid→TiO 2 +TiNb 2 O 7 is revised to be 62.3 mol % TiO 2. TiNb 2 O 7 has been measured to have some solid solubility, and the existence of Ti 2 Nb 6 O 19 at high temperature is confirmed. It would probably form through the peritectic reaction of Liquid + TiNb 2 O 7 →Ti 2 Nb 6 O 19. Moreover, congruent reactions of Liquid→TiNb 2 O 7 and Liquid→TiNb 5 O 14.5 are measured as 1491 °C and ∼1478 °C, respectively. Subsequently, thermodynamic assessment of TiO 2 –Nb 2 O 5 system has been carried out by means of the CALPHAD method, and a set of self-consistent thermodynamic parameters is obtained. Calculated TiO 2 –Nb 2 O 5 phase diagram can reasonably reproduce the available experimental data. The provided TiO 2 –Nb 2 O 5 phase diagram and thermodynamic parameters may be useful to the development of titanium niobates and further multicomponent thermodynamic database. [ABSTRACT FROM AUTHOR]

In this work we evaluate the technical feasibility of using liquefied CO 2 + propane as a solvent for the purification of lubricant oils. A model lubricant made of a silicone oil (polydimethylsiloxane, MW ≈6000) and Decamethylcyclopentasiloxane (D5, MW: ≈371) is prepared to study the extraction process. The phase behavior of the CO 2 +propane+silicone oil system is evaluated in a high-pressure view cell to set the window of operating conditions where the system exhibits partial liquid miscibility (298–323 K). Then, we add D5 monomer (2 mass % in the silicone oil) to the previous ternary mixture, and we assess the effect of solvent composition (CO 2 /propane: 60/40–90/10) over the fractionation process by means of new equilibrium measurements. The solvent-free distribution coefficient of D5 between the liquid phases is determined from experimental determinations. Results evidence that liquefied gases with propane concentrations between 10 and 26 mass % are suitable to remove the monomers from the raw lubricant oils with good selectivity and extraction yields. Conceptual engineering designs of the liquid-liquid fractionation process are performed to determine the suitable solvent composition that completely removes the monomer present in the lubricant oil and to assess the recovery of the lubricant oil. [Display omitted] • Synthetic lubricant purification assessment through liquefied CO2 +propane mixtures. • High CO 2 concentrations in the solvent favors the liquid partial miscibility with the lubricant. • Liquid-liquid-vapor phase equilibrium and phase composition measurements. • Fractionation of Polydimethylsiloxane and Decamethylcyclopentasiloxane model lubricant. • Conceptual engineering design of the liquid-liquid fractionation process using liquefied gases. [ABSTRACT FROM AUTHOR]

CaO–Al 2 O 3 -CeO x slag system is of great significance for designing a new type of metallurgical slag system suitable for rare earth steel. In this paper, the phase equilibria of CaO–Al 2 O 3 -CeO x system were experimentally studied. Isothermal sections of CaO–Al 2 O 3 –Ce 2 O 3 system and CaO–Al 2 O 3 –CeO 2 system at 1600 °C were constructed, respectively. 4 three-phase fields, 5 two-phase fields and a single liquid phase field in CaO–Al 2 O 3 –Ce 2 O 3 system were determined; 2 three-phase fields, 3 two-phase fields and a single liquid phase field in CaO–Al 2 O 3 –CeO 2 system were determined. On this basis, the dissolution process of three typical inclusions (viz. Al 2 O 3 , CeAl 11 O 18 and CeAlO 3) in CaO–Al 2 O 3 –Ce 2 O 3 slag system was discussed. [ABSTRACT FROM AUTHOR]

Phase equilibria in the CaO-TaO 2.5 -YO 1.5 system were experimentally investigated and the isothermal section at 1400 °C was constructed. Ten three-phase equilibrium fields were determined, and the solid solution regions of the binary compounds were analyzed. The Ca 4 Ta 2 O 9 in the ternary system is marked as (YO 3/2) x (Ca 2/3 Ta 1/3 O 3/2) 1−x. Its maximum solubility is the formula of Ca 2 YTaO 6. The solubilities of CaO in the M′-YTaO 4 and fluorite phases reach up to about 2.0 mol% and 8.9 mol%, respectively. A ternary pyrochlore-type phase was found, which was expressed as the chemical formula of Ca 0.5–0.5x Y 0.75x Ta 0.5–0.25x O 1.75. The morphology of pyrochlore was polygonal, and it was the only reaction product when the YTaO 4 oxides were corroded by the molten silicate (CMAS). Since the CaO is the main reactant, the CaO-TaO 2.5 -YO 1.5 phase diagram was used to successfully explain the corrosion behavior of YTaO 4. The current experimental phase diagram is important to understand the CMAS degradation of the thermal barrier coatings. [ABSTRACT FROM AUTHOR]

The binary MgO–ZnO and CaO–ZnO systems and the ternary CaO–MgO–ZnO system were thermodynamically optimized with phase equilibria studies in this study. Bragg-Williams random mixing model was used for solid solutions, while Modified Quasichemical Model was used for liquid solution. The thermodynamic optimization was conducted using Factsage 8.1 thermochemical software. The optimized phase diagrams fit well with phase equilibria experimental results. The phase equilibria studies were performed for the MgO–ZnO systems at 600 °C, 650 °C, 700 °C, and 1000 °C, and for CaO–MgO–ZnO systems at 1500 °C, 1550 °C, and 1600 °C. Quenched samples were analyzed by SEM/EDS to confirm equilibrium phases. Liquid phases were newly observed in the CaO–MgO–ZnO systems at 1550 °C and 1600 °C. [ABSTRACT FROM AUTHOR]

Phase equilibria studies were undertaken on the "CuO 0.5 "-AlO 1.5 -SiO 2 system in equilibrium with metallic copper using equilibration and quenching technique followed by the electron probe X-ray microanalysis (EPMA). The liquidus of the "CuO 0.5 "-AlO 1.5 -SiO 2 system, including the two 2-liquid miscibility gaps in the system as well as the cuprite (Cu 2 O), corundum (Al 2 O 3), delafossite (CuAlO 2), tridymite and cristobalite (Si 1-x (CuAl) x O 2), and mullite (Al 6+2x Si 2-2x O 13-x) primary phase fields has been characterized. New experimental results together with phase equilibria and thermodynamic literature data were used to obtain a self-consistent set of parameters of the thermodynamic model for all phases. The liquidus projection of the "CuO 0.5 "-AlO 1.5 -SiO 2 system was presented for the first time in the full range of temperatures and compositions. It was found that the simultaneous dissolution of a small amount of alumina and copper oxide (CuAlO 2) in SiO 2 phases stabilize cristobalite over tridymite at low temperatures. [ABSTRACT FROM AUTHOR]

Sustainable utilization of Sc 2 O 3 in the bauxite ore residues has recently attracted significant interest in industries and research community. However, few thermodynamic and experimental data has been reported for Sc 2 O 3 systems, which greatly limits the sustainable utilization of Sc 2 O 3 in the bauxite ore residues. This study was carried out to develop an understanding of the phase equilibria of the Al 2 O 3 -SiO 2 -Sc 2 O 3 ternary system and furnish essential information for the recovery of Sc 2 O 3 from the bauxite ore residues. Therefore, a combined thermodynamic assessment and experimental investigation were performed for the Al 2 O 3 -SiO 2 -Sc 2 O 3 ternary system. The phase equilibria of the ternary system based on Al 2 O 3 -SiO 2 -Sc 2 O 3 was established at 1773 K and 1873 K using a thermodynamic equilibrium experiment. The obtained experimental results and findings from a systemic literature survey were utilized for the thermodynamic assessment to arrive at a thermodynamic data set pertaining to the Al 2 O 3 -SiO 2 -Sc 2 O 3 system. Based on the thermodynamic data obtained in the study, isothermal sections at 1773 K and 1873 K were computed, and subsequently, a comparison was made with the available experimental data. The theoretical calculations corroborated quite well with the experimental findings, thereby demonstrating that the current thermodynamic data is credible and self-consistent. [ABSTRACT FROM AUTHOR]

The phase diagram of CaO-Al 2 O 3 -Ti 2 O 3 system has significant implications for the metallurgical slag design of Al-Ti alloy steel. In this work, the high-temperature equilibrium experiments were conducted at 1500 °C and 1600 °C in C/CO equilibrium atmosphere, respectively. The types and compositions of the equilibrium phases were determined by Electron Probe Micro Analysis (EPMA) and X-ray diffraction (XRD). The isothermal section of CaO-Al 2 O 3 -Ti 2 O 3 system in the low w (TiO x) region at 1500 °C was constructed for the first time, in which there are 6 three-phase fields, 7 two-phase fields, and a liquid phase field. The isothermal section of CaO-Al 2 O 3 -Ti 2 O 3 system in the low w (TiO x) region at 1600 °C was constructed and revised, including 3 three-phase fields, 6 two-phase fields, and a liquid phase field. Additionally, under the current experimental condition, the reasons for the formation of TiC in the high w (TiO x) region of this slag system were analyzed, further discussing the effect of carbon on the phase equilibria of CaO-Al 2 O 3 -Ti 2 O 3 system. [ABSTRACT FROM AUTHOR]

A fundamental understanding of the interfacial properties at elevated pressure is essential for processes in the context of the energy transition, such as the storage of CO 2 , H 2 or CH 4. Systems in such processes have traces of impurities. This work aims to systematically investigate these multi-component systems through simplified vapor-liquid-liquid systems comprising H 2 O, (n-butanol or n-dodecane), and (CO 2 or CH 4). The model systems are theoretically investigated using the density gradient theory and the PCP-SAFT. The interfacial tension and saturated phase density of the model systems are experimentally measured by the pendant drop and the oscillating tube method, respectively. Good agreement between the theoretical and experimental results is found. It was found that the pure and binary systems of these mixtures can be described well by the introduced model, delivering high quality predictions. [Display omitted] • Predicted & measured IFT and density. • Competitive- and co-adsorption are observed. • Interfacial behavior was theoretically predicted and experimentally validated. • Interfacial tensions are well estimated by the framework based on binary interactions parameters. • Competitive adsorption, as well as co-adsorption is observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Viable responses to environmental issues related to fossil fuel usage are essential. • Biodiesel, vis-à-vis biomass, is now a sustainable alternative for renewable energy. • The development of renewable energy sources is a tool for sustainability. • The ternary system approach assists in processing constituents for biodiesel. • Scaling up of the ternary system approach for biodiesel fuel processing is necessary. Application of a ternary system (TS) approach involving ternary phase diagrams from liquid-–liquid equilibrium (LLE) data can assist in highlighting constituent components in biodiesel (BD) systems at investigated conditions, thereby improving the purification process. The LLE system is a mass transfer operation in which a liquid solution is contacted with a second immiscible or nearly immiscible liquid selected preferentially to remove desired components based on the solubilities of the components and their chemical differences. Different sources of feedstock for BD production are presented, as well as highlighting the necessity for enhanced feedstock quality to obtain high-quality BD. Different TS studies and approaches over the last few decades are enumerated and discussed. Furthermore, different local composition modelling approaches to the study of TS in BD are presented, highlighting the importance of component phase distribution within the ternary BD system for optimisation of the purification process and validation of experimental results based on simulated models. The ternary approach method can serve as a potential means for designing efficient separation systems that optimise BD purification after the transesterification reaction, thereby improving efficiency, material and operational cost reduction, and the elimination of wastewater generation. In this regard, this paper precisely reviews the separation and purification of BD using TS approaches. [ABSTRACT FROM AUTHOR]

• Phase behaviour associated with SA-SAGD operation is studied. • The thermodynamic model deploys CPA EoS to calculate equilibrium properties. • CPA EoS is parametrized using solvent/bitumen and water/bitumen data. • The model constructs phase diagrams of water/solvent and water/solvent/bitumen. Various fluid phase equilibria happen in solvent-aided steam-assisted gravity drainage (SA-SAGD). An appropriate fluid model is a prerequisite for reservoir simulation, SA-SAGD operation analysis, and the design of various phase behavior experiments. Computational thermodynamics is a powerful tool for phase behavior studies in this application. We used the Cubic Plus Association Equation of State (CPA EoS) to predict equilibrium properties due to the presence of molecules with highly directional attractive forces. Calibration of the thermodynamic model is performed by parametrizing its unknown parameters versus two-phase equilibrium data. The model's prediction capability of three-phase experimental data is evaluated, and it is used to construct the phase diagram of water/multicomponent solvent and water/multicomponent solvent/bitumen systems. For the water/multicomponent solvent system, the T xy diagram is obtained at 25 bar, and various phase equilibria regions are specified. These phase regions are presented on ternary diagrams for water/multicomponent solvent/bitumen systems at 25 bar and 475 K, 480 K, and 485 K. The steam/solvent coinjection analysis shows that at the same pressure, temperature, and steam/solvent composition, the multicomponent solvent/steam coinjection yields more aqueous phase compared to pure solvent/steam. This results in the transfer of more latent heat to bitumen, significantly contributing to its viscosity reduction. Analysis of the SA-SAGD operating conditions shows that a multicomponent solvent outperforms pure solvents in promoting steam condensation. The results aids in designing experiments, reducing the risk of failure of experiments, and saving time and resources in phase behavior studies. [ABSTRACT FROM AUTHOR]

The sub-solidus phase relations in the ternary Nd-Dy-Cu system were determined for an isothermal section at 550 °C. The samples were prepared by arc-melting and subsequent annealing in a protective atmosphere for 120 h. The phases in the prepared samples were characterized by X-ray powder diffraction and scanning electron microscopy, and their composition was determined by energy-dispersive spectroscopy. The intermetallic compounds based on the Dy-Cu system are compatible with compounds based on Nd-Cu-based and exhibit a high degree of solid-state solubility. The crystal structures of the solid solutions and their transformations were determined in detail. In the Cu-rich part of the system, the compound DyCu 7 , which is stable above 700 °C according to literature data, was confirmed under the applied experimental conditions and is connected to NdCu 6 by a tie line. [Display omitted] • Subsolidus phase relations in ternary Nd-Dy-Cu system were determined and a phase diagram was constructed. • Phase assemblage in microstructures was determined using XRD and SEM/EDS analysis. • A series of new intermetallic solid solutions were identified. • The extension of solid solutions was determined by means of XRD and SEM/EDS analysis. [ABSTRACT FROM AUTHOR]

The phase relations of the Al-Cr-Pd ternary system above 1100 °C and the thermodynamic description were lacking to guide the compositional design of the Cr and Pd co-modified aluminide coating. Herein, the isothermal section of the Al-Cr-Pd ternary system at 1150 °C was experimentally determined through scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction. In addition, a thermodynamic description of the ternary system was established by the application of CALPHAD (CALculation of PHAse Diagrams) technique based on the experimental results of the isothermal section at 930, 970, 990, 1020 and 1150 °C. The solidification paths of typical alloys determined in the previous literature were also fitted. A set of self–consistent thermodynamic parameters for the Al-Cr-Pd ternary system was obtained with a reasonable agreement between the experimental and calculated results. The results provide a basis for the compositional design of aluminide coatings and enrich the Al-based database. • A new study of isothermal sections at 1150 °C for the Al-Cr-Pd system has been carried out based on SEM-EDS and XRD analyses. • The thermodynamic description of the Al-Cr-Pd system was carried out using the CALPHAD technique. • A set of self-consistent thermodynamic parameters for the Al-Cr-Pd system was obtained. [ABSTRACT FROM AUTHOR]

Dental amalgam, known for its biocompatibility and ductility, is widely used in restorative materials. In dental crown restorations, studying the interactions between amalgam fillings and crown tissues, particularly the roles of calcium (Ca) and strontium (Sr), is essential for improving function stability and biocompatibility. This study conducts critical literature evaluation and thermodynamic optimization of binary systems involving mercury (Hg) with Ca and Sr, focusing specifically on their suitability for dental amalgam restoration. Using first-principles calculations (FPC), the enthalpies of formation for compounds within the Hg-Ca and Hg-Sr binary systems were calculated in this work. Thermodynamic modeling of the liquid solution employed the modified quasichemical model in the pair approximation (MQM), uncovering significant short-range ordering. Conversely, solid phases were modeled using the compound energy formalism (CEF). The incorporation of FPC proves to be a valuable and effective method, providing essential insights to complement the calculation of phase diagrams (CALPHAD) modeling approach. Ultimately, this research significantly enhances our understanding of the thermodynamic characteristics of Hg-X alloys, with notable implications for their potential application in dental amalgam restoration. [ABSTRACT FROM AUTHOR]

As a core of the high entropy alloys, the Co-Cr-Fe-Ni system has been widely investigated. In the present work, the thermodynamics of the Co-Cr-Fe-Ni system and the atomic mobilities of its fcc phase have been evaluated by means of the CALPHAD approach. First-principles calculations were performed to obtain the total energies for the end-member compounds of the σ phase in the Co-Cr-Fe-Ni system. Combining with the experimental data and thermodynamic modeling of the sub-systems from the literature, a set of self-consistent thermodynamic parameters were derived and extrapolated to obtain a thermodynamic description of the Co-Cr-Fe-Ni quaternary system. In order to verify the accuracy of the model parameters, the phase equilibria of a series of the CoCr x FeNi alloys with different Cr contents were determined using DSC, BSE and XRD analysis. Subsequently, based on the diffusion experimental data, the atomic mobilities of the fcc Cr-Fe-Ni alloys were reassessed using the DICTRA software. A mobility database for the fcc Co-Cr-Fe-Ni quaternary system was constructed by directly extrapolating the atomic mobilities of all sub-systems, and comprehensive comparisons prove the consistency between the present assessments and the experiments. In addition to the direct extrapolation approach, extra four-body interaction parameters concerning all four components were added and assessed. The results demonstrate that the extra interaction contributions are ignorable, so that the direct extrapolation from the sub-systems to the quaternary system is feasible in the fcc Co-Cr-Fe-Ni quaternary system. [ABSTRACT FROM AUTHOR]

Nickel-based superalloys are extensively utilized in aerospace engines, marine gas turbines, and other environments with severe operating conditions. The phase relations of the Ni-Mo-Y ternary system were experimentally studied across the entire composition range at 800 °C and 1000 °C using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Thirteen three-phase regions were confirmed at 800 °C, and eleven three-phase regions were observed at 1000 °C. No ternary compound was observed at these temperatures. In addition, the experimental results indicate that molybdenum (Mo) has almost no solubility in the binary compounds found in the Ni-Y binary system. Furthermore, the primary solidification phases and the solidification process of typical alloys were investigated, and three different primary solidification phases were found. Based on the experimental results, thermodynamic calculations for the Ni-Mo-Y system were performed through the CALPHAD technique. The experimental results agree well with the calculated, a set of self-consistent thermodynamic parameters for the Ni-Mo-Y ternary system was obtained in the present work. [ABSTRACT FROM AUTHOR]

[Display omitted] • The stability and structural characteristics of Xe + LMGS hydrates were investigated. • The equilibrium curves of Xe + MCH and Xe + NH hydrates deviated from that of pure Xe hydrate. • Xe + MCH + water and Xe + NH + water systems formed sH hydrates under low pressure conditions. • MCP did not participate in sH hydrate formation with Xe throughout the pressure range. • MD simulations indicated the instability of the sH (Xe + MCP) hydrate. In this study, the influence of different types of large-molecule liquid substances (LMGSs) and formation conditions on the stability and structural transformation of Xe + LMGS hydrates was investigated using phase equilibria, powder X-ray diffraction (PXRD), 129Xe NMR spectroscopy, and molecular dynamics (MD) simulations. The phase equilibria of Xe hydrates in the presence of three different LMGS types (neohexane [NH], methylcyclopentane [MCP], and methylcyclohexane [MCH]) were measured in the pressure range of 0.1–1.0 MPa. The equilibrium curves of Xe + MCH and Xe + NH hydrates shifted away from that of pure Xe hydrate under low pressure, whereas they coincided with that of pure Xe hydrate under high pressure. Interestingly, the equilibrium curve of Xe + MCP hydrate aligned with that of pure Xe hydrate throughout the pressure range. PXRD and 129Xe NMR analyses demonstrated that the equilibrium curve shift under low pressure was caused by the formation of sH (Xe + LMGS) hydrates, which was attributed to the inclusion of NH or MCH. However, MCP did not participate in sH hydrate formation with Xe. MD simulations revealed that MCP in the large cages did not contribute to the thermodynamic or dynamic stability of sH hydrates. The findings of this study provide valuable insights into the development of hydrate-based noble gas capture and storage. [ABSTRACT FROM AUTHOR]

Phase equilibria in the RbCl–CoCl 2 ·2H 2 O–H 2 O system were investigated, single crystals of double rubidium–cobalt chloride dihydrate were obtained, and its structure and optical properties were studied. The regions of crystallization of compounds in the three-component system under study were delimited. Rb 2 CoCl 4 ·2H 2 O crystals were grown by controlled decrease in the temperature of a saturated aqueous solution. Using X-ray diffraction analysis, the crystal lattice parameters of Rb 2 CoCl 4 ·2H 2 O were obtained and the structure of the crystals was refined. The spectral characteristics of the obtained crystals and the corresponding aqueous solution were studied in the λ range 200–800 nm. • Phase equilibria in the RbCl–CoCl 2 ·2H 2 O–H 2 O system were studied. The crystallization regions of RbCl, Rb 2 CoCl 4 ·2H 2 O, RbCoCl 3 ·2H 2 O and CoCl 2 ⋅6H 2 O phases are delineated. • Rb 2 CoCl 4 ·2H 2 O crystals were grown for the first time, suitable for clarifying the crystal structure and investigating its optical properties. • Differences in the optical transmission spectra of the Rb 2 CoCl 4 ·2H 2 O crystal and its mother solution were revealed. • A change in the short-range coordination environment of the Co2+ ion was shown to lead to a shift in the crystal transmission band compared to KCSH. [ABSTRACT FROM AUTHOR]

Modern thermodynamic models, such as the PC-SAFT equation of state, are very accurate but also computationally intensive, which limits their applicability to process design optimization, for example. Surrogate models, which can be evaluated quickly, can be used to approximate the thermodynamic equilibria. However, this requires many data points from the flash calculation routine. In this paper, we investigate three approaches to reduce the number of samples and thus the effort needed to train the surrogate models. First, Sobolev training is used, where the surrogate model is trained not only on the output values, but also on derivative information. Second, data augmentation along the tie lines in LLE systems is proposed to generate samples without additional flash calculations. Third, adaptive sampling is revisited with a novel quality criterion. It is shown that the combination of these techniques can be used to significantly reduce the number of samples required. • An extensive neural network hyperparameter screening for pT-flash surrogate modeling is conducted. • Sobolev training and data augmentation are introduced to reduce the necessary number of samples. • Adaptive sampling is revisited and combined with Sobolev training and data augmentation for improved accuracy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Literature is reviewed on Laves-phase polymorphism of NbCr 2. • A recent work proposing existence of a C14 high-temperature phase is refuted. • C14-NbCr 2 is metastable at all temperatures in the Cr–Nb system. • C15-NbCr 2 Laves phase is the only stable Laves phase in the Cr–Nb system. • Possible directions of future research on the polymorphism are described. This work comments on a recent publication by Hajra et al. (Mater. Design 236 (2023) 112483), which claims to have presented compelling experimental and theoretical evidence in favour of the existence of an equilibrium C14-NbCr 2 high-temperature Laves phase in the Cr-Nb system. In the present comment, evidence and conclusions reported in the paper of Hajra et al. are critically put into context of insight from previous works. From this it is concluded here, that the evidence in favour of an equilibrium C14-NbCr 2 high-temperature Laves phase is, by far, not that compelling as claimed by Hajra et al.. Instead, the most direct evidence presented in the literature does not support the existence of an equilibrium C14-NbCr 2 high-temperature Laves phase. Alternative interpretations of Hajra et al.'s evidence and conclusions are offered, and it is elaborated, which true gaps in knowledge exist concerning the Laves phases in the Cr-Nb system. [ABSTRACT FROM AUTHOR]

The article describes how substitution of chromium by copper affects phase equilibria in Fe–Ni–Co–Cr high-entropy alloy. The alloys with copper content ranging from 0 to 20 % (at.) of Cu were prepared. The alloys were equilibrated at 900, 800, 700, and 650 °C. The samples were investigated by electron microscopy, EDX spectroscopy, and EBSD method. The face-centred cubic phases have only occurred in equilibrated alloys: austenite matrix, copper-rich FCC(Cu) phase, and regions containing these phases. The compositions of equilibrated samples at annealing temperatures are given. Fine microstructures including a semicoherent FCC phase rich in Cu and an FCC phase including the main magnetic elements (Fe, Co, Ni) were formed. The experimental results were compared with the calculated phase equilibria obtained by the CALPHAD method. [Display omitted] • The high entropy alloys (HEAs) prepared at high and slow cooling rates. • Equilibrium states of HEAs: (FeCoNi) 0.75 Cr 0.25-x Cu x (x = 0 to 0.2) studied. • Influence of Cr/Cu substitution on phase equilibria. • Microstructural study of equilibrium phases and technological impurities. • Spinodal decomposition by CALPHAD approach. • New information on the experimental study of the spinodal decomposition. [ABSTRACT FROM AUTHOR]

[Display omitted] Stimuli-responsive lyogels are considered to be smart materials due to their capability of undergoing significant macroscopic changes in response to external triggers. Due to their versatile and unique properties, smart lyogels exhibit great potential in various applications such as drug delivery or actuation processes. While Poly-N-isopropylacrylamide (pNIPAM) is widely known as a thermo-responsive material, it also shows significant solvent-responsive swelling behavior. For the systems tested, polar solvents induce strong swelling due to hydrogen bonding with the amide group, nonpolar solvents lead to significant shrinkage of the lyogels. The aim of this study is to investigate and to model this behavior for future application in chemical or biochemical reactors. As a current area of research, incorporating smart lyogel technology into (bio-)chemical reactors facilitates the development of smart reactor systems. Applying thermodynamic modelling with the gE model COSMO-RS on the monomer or oligomers of pNIPAM, the correlation between solvent-polymer interactions and the degree of swelling can be observed. pNIPAM derivatives exhibit low infinite dilution activity coefficients (IDACs) in polar solvents with large degrees of swelling, while displaying an increase of IDACs in nonpolar solvents. Hydrogen bonds dominate the swelling behavior of lyogels not only in pure solvents but also in mixtures of solvents with varying polarity. Even in mixtures containing high amounts of nonpolar solvents, large degrees of swelling were observed due to the uptake of the polar solvent in the lyogel matrix. This effect can be observed in binary solvent mixtures but also in representative mixtures along an esterification reaction with varying carboxylic chain length of alcohol and carboxylic acids. [ABSTRACT FROM AUTHOR]

Decarbonising the global energy system involves several critical aspects, such as enhancing energy efficiency, expanding electrification, adopting alternative fuels, and leveraging hydrogen, among other strategies. Cold and cryogenic energy have substantial potential sources, extending beyond liquefied natural gas, as the demand for several alternative fuels and substances continues to grow. This study explores various techniques for harnessing cold energy to generate power, ranging from simple to complex technologies. It conducts a comparative analysis of promising technologies suitable for converting cold and cryogenic energy into power. Furthermore, it provides a detailed performance comparison for each technology and outlines prospects for future development. In the end, the study discusses the potential direction of further research and underscores the increasing significance of integrating cold and cryogenic energy into existing business models and value chains, not only as a means of transportation but also as a source of power generation. Harnessing cold and cryogenic energy as a seasonal Carnot battery presents a compelling and innovative solution. This advanced system offers significant potential, especially when integrated with variable renewable energy sources or waste heat, providing a promising option for enhancing energy efficiency and sustainability. [Display omitted] • Several alternative fuels and substances in large industries are discussed. • Several promising thermodynamic cycles and thermoelectric have been reported. • The performance of the selected cold energy-to-power conversion is compared. • The challenges and future trends of cold energy-to-power conversion are discussed. [ABSTRACT FROM AUTHOR]

The lack of thermodynamic data such as the phase diagram of CaO–SiO 2 –Nb 2 O 5 –Fe 2 O 3 –TiO 2 system has seriously hampered the comprehensive utilization of niobium, titanium and other resources in the Bayan Obo tailing. In this study, phase equilibria of the CaO–SiO 2 –Nb 2 O 5 –Fe 2 O 3 –TiO 2 system at 1200 °C were investigated using high temperature equilibrium experiment for the first time, and the CaTiO 3 –Ca 10 Nb 2 Si 6 O 27 –Ca 2 SiO 4 –Ca 2 Nb 2 O 7 solid phase coexistence region was determined. Afterwards, based on the high temperature equilibrium experiments, the liquidus surfaces of the liquid + CaTiO 3 and liquid + SiO 2 equilibrium coexistence regions in CaO–SiO 2 –Nb 2 O 5 -5 wt % Fe 2 O 3 –TiO 2 system at 1200 °C were calculated using mathematical methods of interpolation and fitting. Finally, the 1200 °C isothermal phase diagrams of CaO–SiO 2 –Nb 2 O 5 -5 wt %Fe 2 O 3 –TiO 2 system were plotted. The results of the study can provide theoretical guidance for the enrichment and extraction processes of niobium and titanium resources in the Bayan Obo tailing. [ABSTRACT FROM AUTHOR]

The utilization of rare earth resources, especially secondary resources (e.g., RE-oxide system slag), has been limited by the lack of thermodynamic information. In order to supplement and improve the thermodynamic data related to rare earth, the equilibrium experiments of SiO 2 –Ce 2 O 3 –CaO-25 wt %Al 2 O 3 system phase diagram was carried out at 1673 K and 1773 K by the high-temperature isothermal equilibration/quenching technique in current paper. The composition of seven phase regions were determined by FE-SEM, XRD, EPMA and XRF analysis on the samples obtained by high temperature equilibrium technology at 1673 K and 1773 K, including the primary crystal regions of three compounds (C 2 AS, 2CaO·SiO 2 , CaO·2Ce 2 O 3 ·3SiO 2) and three three-phase coexistence regions (L + C 2 AS + 2CaO·SiO 2 , L + C 2 AS + CaO·2Ce 2 O 3 ·3SiO 2 , L + CaO·2Ce 2 O 3 ·3SiO 2 +CeAl 11 O 18) and a liquid region. The phase relations and isotherms of SiO 2 –Ce 2 O 3 –CaO-25 wt %Al 2 O 3 system obtained in current work are beneficial to the recycling of rare earth resources containing cerium. [ABSTRACT FROM AUTHOR]

• The phase equilibria around LPSOs in Mg-Ni-Y system are experimentally determined. • The thermodynamic stability of LPSOs is discussed based on DFT calculations. • A distort 12R structure is observed through SEAD and HRTEM. • The phase diagram of Mg-Ni-Y system is optimized considering the new 12R LPSO. The long-period stacking ordered phases (LPSOs) in Mg−Ni−Y system have been attracting great interest as effective strengthening components because of their unique structural characteristics and deformation mechanism. However, the phase relationships in LPSOs are complicated and unclear, which restricts the design of advanced magnesium-based alloys. The aim of the present work is to experimentally determine the phase equilibria relationships focusing on LPSOs and establish the thermodynamic description for Mg−Ni−Y system. Four types of LPSOs, that is, 14H, 12R, 18R and 10H, are confirmed through equilibrated alloys and high-resolution transmission electron microscopy (HR-TEM). The formation enthalpies of LPSOs (14H, 12R, 18R and 10H) are calculated based on density functional theories (DFT) calculations. A new ternary compound, termed as τ phase, is observed for the first time which is likely to be the distorted structure of 12R as determined from the TEM image which shows a 12-layer closed packing plane distance of 3.252 nm and a shear angle of 83.2° between (0002) and (10 1 ¯ 0) planes. Based on the determined phase equilibria relationship, the Mg−Ni−Y system is assessed and a self-consistent description is obtained where the LPSOs are modeled as the stoichiometric compounds. The comparison between the calculation result and experimental data suggests the accuracy of the present thermodynamic database in the Mg-rich corner. [ABSTRACT FROM AUTHOR]

Cerium oxide doped with oxides of rare earth elements is a multifunctional material, a wide range of uses which is associated with its unique physicochemical properties. Phase diagrams of multicomponent systems are the physicochemical basis for the creation of new materials with improved characteristics. In this work, phase equilibria in ternary CeO 2 –La 2 O 3 –Dy 2 O 3 and binary La 2 O 3 –Dy 2 O 3 systems in the whole concentration range were studied. No new phases have been identified in these systems. An isothermal section of the phase diagram of the CeO 2 –La 2 O 3 –Dy 2 O 3 system at a temperature of 1500 °С is constructed. No new phases have been detected in the system. It was found that in the studied ternary system solid solutions are formed on the basis of (F) modification of CeO 2 with structure of fluorite type, monoclinic (B), cubic (C) and hexagonal (A) modifications of Ln 2 O 3. In the La 2 O 3 –Dy 2 O 3 binary system (1500–1100 °С) three types of solid solutions are formed: based on hexagonal modification A-La 2 O 3 , monoclinic modification B-Dy 2 O 3 and cubic modification C-Dy 2 O 3 separated by two-phase fields (A+B) and (B+C), respectively. The boundaries of the regions of homogeneity of solid solutions based on A-La 2 O 3 are determined by compositions containing 35–40, 20–25, 15–20 mol% Dy 2 O 3 at 1500, 1250, 1100 °C, respectively. From the obtained data it follows that the solubility of Dy 2 O 3 in the hexagonal modification of lanthanum oxide is 39 mol% at 1500 °C, 23 mol. % at 1250 °C and 16 mol% at 1100 °C. The limits of existence of solid solutions based on monoclinic B-modification are determined by compositions containing 30–35, 65–60 (1250 °С), 35–40, 55–60 (1100 °С) 40–45, 70–75 (1500 °C) mol% Dy 2 O 3. In the studied system, with a decrease in temperature from 1500° to 1100°C, there is a decrease in the solubility of La 2 O 3 in the crystal lattice of cubic solid solutions of C-type from 16 to 10 mol%. [ABSTRACT FROM AUTHOR]

Hydrate-based gas separation (HBGS) needs a kinetic promoter to increase its economic value. The kinetic promoters for HBGS should have low foaming ability, high performance on increasing the conversion rate of the water into hydrate (R WH) and little thermodynamic inhibition on hydrate formation. However, no reported kinetic promoter meets all above requirements at same time. According to the experimental results in this work, n-octyl-β- d -glucopyranoside (OGP) met all those requirements of HBGS. For that reason, OGP was proposed as a new kinetic promoter for HBGS, and its effects on HBGS were revealed by investigating the HBGS of hydrogen and ethylene from fluid catalytic cracking dry gas in presence of OGP in this work. OGP enhanced the HBGS performance by increasing R WH from less than 64% to higher than 84%. By one-step separation, the hydrogen concentration was increased from 26.0 mol% to about 46.8 mol% while the ethylene concentration was increased from 52.0 mol% to about 74.4 mol%. The effect of the initial OGP concentration in liquid phase (w p,0) on HBGS increased with the increase in R WH , and the optimum w p,0 was 0.20 mass%. The processing capacity of the OGP solution in the HBGS was about 350 NL feed gas/L. OGP enhanced the promotion of increasing pressure on the HBGS performance. A new model was proposed to predict the thermodynamic equilibrium hydrate formation pressures of the experimental systems: the maximum relative deviation is 5.08% and the average relative deviation is 2.61%. [Display omitted] • OGP increased R WH from less than 64% to higher than 84%. • The hydrogen concentration was increased from 26.0 mol% to about 46.8 mol%. • The ethylene concentration was increased from 52.0 mol% to about 74.4 mol%. • The processing capacity of the OGP solution in the HBGS was 350 NL feed gas/L. • A new model was proposed to quantitatively analyze the effect of OGP on HBGS. [ABSTRACT FROM AUTHOR]