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The present study focused on the phase equilibria in the PbO‐CaO‐AlO1.5 and PbO‐CaO systems in air. The high‐temperature phase equilibria in these systems were studied using the high‐temperature equilibration and quenching technique. The compositions of phases present in the quenched samples were then measured using the electron probe X‐ray microanalysis. The liquidus of the PbO‐CaO‐AlO1.5 system in air, including Ca3Al2O6, Ca12Al14O33, (Ca,Pb)Al2O4, CaAl4O7, (Ca,Pb)Al12O19, Ca2PbO4, corundum (Al2O3), lime (CaO), massicot (PbO), Pb9Al8O21, PbAl2O4, and PbCa2Al8O15 primary phase fields as well as the immiscibility gap in the liquidi of Ca3Al2O6, Ca12Al14O33, and (Ca,Pb)Al2O4 have been experimentally characterized. The experimental data obtained were used for the thermodynamic optimization of a self‐consistent set of parameters of the thermodynamic model for all phases of the PbO‐CaO‐AlO1.5 system in air, 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 in support of the development and optimization of pyrometallurgical processes. The predicted liquidus projection of the PbO‐CaO‐AlO1.5 system was presented for the first time in the complete range of temperatures and compositions. [ABSTRACT FROM AUTHOR]

The system BaO–TiO2 is technically important because it contains multiple dielectric and ferroelectric phases, including the important BaTiO3, which is one of the most widely studied dielectric perovskites owing to its dual piezoelectric and ferroelectric properties. The present work revises the subsolidus phase equilibria data by synthesizing previous phase equilibria data and new experimental results using high‐temperature (600°–1300°C) and long‐term (≤336 h) equilibration, coupled with analytical work based principally on room‐temperature X‐ray diffraction. The resultant phase diagram is given in both mole and weight percents, extending from the liquidus surface (not investigated) to absolute zero temperature (for inclusion of the previously excluded crystallographic and ferroelectric phase transformations). The major features include (1) correction of four eutectoid and three peritectoid reactions and corresponding temperatures, (2) indication of inferred partial solid solubilities, (3) clarification of the BaTiO3 solid solubility homogeneity regions, and (4) specification of some invariant point compositions on the liquidus surface. [ABSTRACT FROM AUTHOR]

The reservoir fluid PVT model is necessary to all types of hydrodynamic modelling (field development, well flow, well test, basin modelling, etc.). The PVT model, when not properly tuned, can result in significant inaccuracies in calculating PVT properties and field production of volatile oil and gas-condensate systems. The process of tuning the reservoir fluid PVT model is a complex and time-consuming task. Various methods, such as regression and machine learning (ML), have been employed for reservoir oil PVT model tuning; however, a definitive approach has not yet been identified. This paper introduces a novel and efficient step-by-step approach for developing and tuning reservoir fluid PVT which enables engineers to tune PVT models much faster than before. The new proposed approach can assist in the initialisation of a PVT model by employing effective methods for initial data pre-processing. Furthermore, it can accurately reproduce the results obtained from field measurements and basic laboratory studies conducted on representative samples, in a model using a cubic equation of state. Tuning the PVT model enables the reliable modelling of the PVT properties of all five types of reservoir fluids (black oil, volatile oil, gas condensate, wet gas, dry gas) in various applications; the applications include the design and monitoring of field development, multiphase flow calculations in wells and field pipelines, and basin modelling. It is possible to algorithmise and automate the application of this approach in specialised software. This study considered eight Russian reservoir oil and gas-condensate systems, for which the PVT models were tuned, using the proposed approach. The comparison between proposed approach and other tuning methods in modern PVT simulators (PVTi, PVTsim, Multiflash, PVT Designer) is shown in the article. These examples show the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

The system BaO–TiO2 is technically important because it contains multiple dielectric and ferroelectric phases, including the important BaTiO3, which is one of the most widely studied dielectric perovskites owing to its dual piezoelectric and ferroelectric properties. The present work revises the subsolidus phase equilibria data by synthesizing previous phase equilibria data and new experimental results using high‐temperature (600°–1300°C) and long‐term (≤336 h) equilibration, coupled with analytical work based principally on room‐temperature X‐ray diffraction. The resultant phase diagram is given in both mole and weight percents, extending from the liquidus surface (not investigated) to absolute zero temperature (for inclusion of the previously excluded crystallographic and ferroelectric phase transformations). The major features include (1) correction of four eutectoid and three peritectoid reactions and corresponding temperatures, (2) indication of inferred partial solid solubilities, (3) clarification of the BaTiO3 solid solubility homogeneity regions, and (4) specification of some invariant point compositions on the liquidus surface. [ABSTRACT FROM AUTHOR]

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]

By the example of the Tigrinoe tin–tungsten greisen deposit, Primorye (Russia), and based on the literature data on the composition of melt and fluid inclusions in minerals, conditions that are favorable for the formation of tin-bearing granites, mobilization of tin from them, and subsequent deposition of cassiterite are considered. It is shown that the factors favoring the formation of tin deposits related to granitoid magmatism include the following: (1) relatively low-temperature and shallow granites (720‒770°С/0.7‒2 kbar, 3‒6 km) formed under reducing conditions (fugacity of oxygen fO2 below the fayalite–magnetite–quartz buffer, QFM), which is indicated by the absence of magnetite/presence of ilmenite, and by a reduced Ce anomaly in granite zircon; (2) low-salinity single-phase or two-phase fluid inclusions in magmatic quartz (vapor dominating the brine); and (3) fluid inclusions with the СН4/СО2 ratio of 0.1‒0.3 in the ore-vein minerals. A number of problems related to the formation of tin–tungsten deposits require further studies. First of all, this concerns the appraisal of the role of fluorine in magmatic accumulation and hydrothermal transport of tin. The partitioning of Sn and W between the granite melt and the fluids under strongly reducing conditions (at fO2 below the QFM buffer) also has to be evaluated experimentally. [ABSTRACT FROM AUTHOR]

Mineral chemistry records the pressure and temperature conditions of lithospheric processes. Active tectonic margins, however, are subjected to non‐hydrostatic stresses wherein stress magnitudes vary directionally, and the impact of non‐hydrostatic stress on mineral chemistry is uncertain. The work of materials scientists F. Larché and J. Cahn provides a framework for quantifying how stress affects mineral chemistry. Crystallographically and mechanically anisotropic, multicomponent minerals will have different compositions as a function of their orientation under a fixed stress meaning that grain‐to‐grain compositional variation can be used to estimate stress. We develop two "orientation piezometry" methods that use the chemistry and orientations of multicomponent, anisotropic minerals to estimate stress. The first method uses chemistry and orientation ("coupled orientation piezometry") whereas the second method uses composition alone ("decoupled orientation piezometry"). We apply the methods to clinopyroxene and feldspar solid solutions using synthetic data sets. The first method determines the full stress tensor whereas the second method can only determine the differential stress magnitude unless additional a priori information is specified. Plausible scenarios for orientation piezometry include minerals undergoing diffusion creep, recrystallized grains formed during dislocation creep, and minerals grown statically under stress. Preliminary application of the decoupled piezometer to the famous eclogite facies shear zones on Holsnøy, Norway, suggests differential stresses in the range of 300–900 MPa, broadly consistent with previous estimates from the area. Thus, orientation piezometry techniques may provide valuable constraints on geodynamic processes and insights into long‐standing geological problems such as the relationship between pressure and depth. Plain Language Summary: The chemical compositions of minerals are a function of the pressure and temperature conditions at which they form. But minerals formed in many of the most geologically important regions such as subduction zones and mountain belts are subjected to stresses that are not equal in all directions. Unequal stresses pose a problem for existing techniques that use mineral compositions to estimate pressures and temperatures because these techniques implicitly assume minerals form under a uniform pressure where stresses are equal in all directions. Recent theoretical developments have allowed us to calculate the expected chemistry of minerals for the case of unequal stresses and have revealed that mineral chemistry depends on the orientation of a crystal's lattice relative to the direction of the stresses. This is because the strength and size of the crystal lattice differs directionally. Here, we have developed statistical methods that use the chemical differences among minerals with different orientations to calculate the stresses under which they formed. This is an exciting development because the magnitudes of stresses in Earth are generally challenging to determine but very important for understanding Earth processes. Key Points: The equilibrium compositions of multicomponent minerals vary as a function of crystallographic orientation in a fixed stress fieldOrientation piezometry uses composition and orientation data from many mineral grains to determine paleo‐stressesOrientation piezometry may be applied to grains in diffusion creep or to recrystallized grains formed during dislocation creep as examples [ABSTRACT FROM AUTHOR]

During his time at Royal Institute of Technology (Kungliga Tekniska högskolan) in Sweden, the present author learned nonequilibrium thermodynamics from Mats Hillert. The key concepts are the separation of internal and external variables of a system and the definitions of potentials and molar quantities. In equilibrium thermodynamics derived by Gibbs, the internal variables are not independent and can be fully evaluated from given external variables. While irreversible thermodynamics led by Onsager focuses on internal variables though often mixed with external variables. Hillert integrated them together by first emphasizing their differences and then examining their connections. His philosophy was reflected by the title of his book "Phase Equilibria, Phase Diagrams and Phase Transformations" that puts equilibrium, nonequilibrium, and internal processes on equal footing. In the present paper honoring Hillert, the present author reflects his experiences with Hillert and his work in last 40 years and expresses his gratitude for all the wisdom and support from him in terms of "Hillert nonequilibrium thermodynamics" and discusses some recent topics that the present author has been working on. [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]

Cyclic alcohols are commonly found in natural and synthetic products and are involved in many biological processes. An ability to model their thermodynamic properties is of interest in food, flavouring, and pharmaceutical manufacturing, particularly for mixtures for which available experimental data are limited. Good examples are mixtures including menthol, a naturally occurring cyclic alcohol widely used in the food and pharmaceutical industries, well-known for its cooling-sensation properties and its role in the discovery of the TRPM8 receptor. Here, we extend the SAFT-γ Mie group-contribution method to model cyclic alcohols, by introducing a new cCHOH group (c for cyclic) composed of two identical Mie segments. Three association sites (two electronic sites of type e and one hydrogen site of type H) are also included to mediate hydrogen bonding. New parameters that characterise the group interactions (one new like interaction and 26 new unlike interactions) are developed and are employed to determine the thermophysical properties (vapour pressure, saturation density, vaporisation enthalpy, and second-order thermodynamic derivative properties) of pure cyclic alcohols, and mixture properties (vapour–liquid equilibria, liquid–liquid equilibria, solid–liquid equilibria, density, and excess enthalpy) of cyclic alcohols in several solvents. The quality of the model is evaluated by comparing predictive calculations with experimental data of 76 systems: six pure fluids and 70 binary mixtures, selected from a large range of solvent families: cyclic, linear, and branched alkanes, 1-alcohols, 2-alcohols, 2-ketones, esters, aromatic compounds, water, and carbon dioxide. Very good overall agreement is found, including for the prediction of solid–liquid solubility, which confirms the transferability of the new group parameters. Together with previously developed parameters, these open the way for the prediction of the thermodynamic properties of further complex mixtures. [ABSTRACT FROM AUTHOR]

Bimodal magmatism is characteristic of the geodynamic evolution of the Main Ethiopian Rift (MER), which is a reference area for the study of the processes leading to continental break-up before seafloor spreading. There are abundant emissions of basalts and rhyolites, which are in possible parent–daughter relationships. However, the P – T –H2O conditions of production and storage of the basaltic end member remain unclear. Crystallization experiments have been conducted on an alkali basalt from the MER to define its pre-eruptive conditions and shed light on the compositional evolution of derivative liquids and source conditions. The experiments were performed at 100 to 200 MPa, 975°C to 1080°C, varying H2O/CO2 ratios, corresponding to melt water contents of 1 to 5 wt %, at f O2 slightly lower than the Fayalite-Magnetite-Quartz (FMQ) solid buffer. Comparison between the petrological attributes of the starting rock and the experiments shows that the basaltic magma was stored at 150 to 200 MPa, 1050 ± 10°C, with 1 to 2 wt % H2O in melt, with f O2 near FMQ prior to eruption. Geochemical modelling shows that the corresponding mantle source contained about 0.1 wt % H2O, reflecting a metasomatized source. Extensive crystallization of such basalts produces SiO2-rich liquids, which are not yet peralkaline, however. This underscores that extreme fractionation (>90 wt %) is required in order to produce peralkaline derivatives from mildly alkaline basalts. This extreme fractionation and the water-rich nature of the starting basalt readily explain the H2O-rich condition of peralkaline rhyolites that have fueled caldera forming eruptions in the Rift. [ABSTRACT FROM AUTHOR]

Sulfate-type salt lakes constitute over half of the total salt lakes in China and are rich in rare elements, such as rubidium and cesium. However, the complex interactions between ions make the separation and extraction process quite challenging. To address this, phase equilibrium studies were conducted on the sulfate system containing rubidium, cesium, and magnesium. Specifically, the phase equilibria of the aqueous quaternary system Rb+, Cs+, Mg2+//SO42− - H2O at 323.2 K were investigated using the isothermal dissolution method. The solubility, density, and refractive index of the system were experimentally measured. The results indicate that the system at 323.2 K belongs to a complex type with the formation of one solid solution (Rb, Cs)2SO4 and two double salts (Rb2SO4·MgSO4·6H2O, Cs2SO4·MgSO4·6H2O). The corresponding phase diagram consists of four quaternary invariant points, nine univariate curves, and six crystallization regions. Among these, the crystalline region for Cs2SO4·MgSO4·6H2O is the largest, while that for the single salt Cs2SO4 is the smallest. Moreover, the crystalline regions for the double salt and solid solutions are significantly larger than those for the single salt, highlighting the difficulty in separation of valuable single salts. A comparison of multi-temperature phase diagrams from 298.2 K to 323.2 K reveals that the crystalline form of MgSO4 changes from MgSO4·7H2O (298.2 K) to MgSO4·6H2O (323.2 K). As the temperature increases, the phase regions for Rb2SO4, Cs2SO4, (Rb, Cs)2SO4, and Cs2SO4·MgSO4·6H2O expand, while the phase region of Rb2SO4·MgSO4·6H2O contracts, indicating that the single salts (Rb2SO4, Cs2SO4) are more readily precipitated at higher temperature, which provides theoretical guidance for the future production and separation of Rb, Cs, and Mg from sulfate-type salt lakes. [ABSTRACT FROM AUTHOR]

Elements with a high affinity for O and S in molten steel are desirable as deoxidizing and desulfurizing agents in the steel refining process, and Ce has attracted attention. In this study, the thermodynamic properties of sulfur in a CaO–AlO1.5–CeO1.5 slag system at 1873 K are investigated. A chemical equilibrium method using Cu is employed for these measurements. Sulfide capacities are determined in the CaO–AlO1.5–CeO1.5 system to show desulfurization ability; the precipitated phases are identified when large amounts of sulfur are added to the CaO–AlO1.5–CeO1.5 system; the solubility of CaS in the CaO–AlO1.5–CeO1.5 system is determined. It is suggested that the slag of this system can improve sulfur distribution while reducing the Al concentration in the steel. [ABSTRACT FROM AUTHOR]

Phase equilibria in the ZrO2–YO1.5–NbO2.5 system were experimentally studied at 1300°C, and a comparison with the existing ZrO2–YO1.5–TaO2.5 (ZYTO) was conducted. Ternary fluorite phases on the Y:Nb > 1 side extend from binary ZrO2‐YO1.5 to YO1.5–NbO2.5 system, generating a continuous solid solution region. Furthermore, it was observed that three phases of M‐YNbO4, fluorite, and m‐ZrO2 were in equilibrium. On the Y:Nb < 1 side, two three‐phase equilibrium regions were measured, namely M‐YNbO4+m‐ZrO2+O‐Nb2Zr6O17 and h‐Nb2O5+O‐Nb2Zr6O17+M‐YNbO4. The tetragonal YNbO4 and ZrO2 phases both extend nearly along with Y:Nb = 1. The t‐ZrO2 phases with slightly lower stabilizer content were found to transform into their monoclinic polymorph during the cooling process. However, in the ZrO2–YNbO4 subsystem, the tetragonal ZrO2 was nontransformable due to larger YO1.5 and NbO2.5 co‐dopants, and the maximum solubility is about 18.1 mol%. Upon cooling, the tetragonal YNbO4 phase, even with the maximum ZrO2 content, is transformable to monoclinic form. The maximum solubility of ZrO2 in YNbO4 is determined to be about 20.7 mol%. Finally, the high‐temperature liquidus in the ZrO2–YNbO4 system was first determined based on the cooling traces, and a vertical section diagram was proposed for further speculation. A eutectic reaction of Liquid→YNbO4+ZrO2 was discovered, and the eutectic composition and temperature were measured as 39.2ZrO2–29.2YO1.5–31.6NbO2.5 and 1813°C. This study provides the basis for thermodynamic assessment of ZrO2–YO1.5–NbO2.5 and is valuable for the design and development of the ZrO2–YO1.5–NbO2.5‐based ceramic materials. [ABSTRACT FROM AUTHOR]

Phase relations in the subsolidus area of the MgO–P2O5–Cr2O3 system were reinvestigated. The reactions were carried out by the method of multi-stage calcination of samples in the temperature range of 350–1150 °C. As a result of the conducted research, a new pyrophosphate with the formula Mg5Cr2 (P2O7)4 was discovered. This compound, crystallizing in the orthorhombic system, most likely exhibits the Fe52+Fe23+ (P2O7)4 structure. The infrared spectrum of the new pyrophosphate was presented. Mg5Cr2 (P2O7)4 melts incongruently at 1330 °C depositing Mg3Cr4 (PO4)6. The developed division of the MgO–P2O5–Cr2O3 system into subsidiary subsystems differs significantly from the one known from the literature. First of all, unlike in the literature, it takes into account the existence of the compound just discovered, as well as the other two phosphates, i.e. Mg3Cr4 (PO4)6 and Cr2P4O13. The melting points of mixtures of phases coexisting in the equilibrium state were estimated by the pyrometric method. All phosphates (V) with mixed cations, i.e. Mg5Cr2 (P2O7)4, Mg3Cr4 (PO4)6 and MgCr2 (P2O7)2, were tested for their use for colouring lead-free glaze fired once at 1050 °C. It turned out that the investigated phosphates act as dyes and ceramic layers of good quality and interesting colours were obtained. The optimal concentration of the applying phosphates was close to 3 mass%. [ABSTRACT FROM AUTHOR]

The phase diagram of the CaO-SiO2-Nb2O5-Fe2O3-TiO2 slag system has important significance for guiding the recycling and utilization processes of metallurgical slags containing niobium and titanium. In this paper, high-temperature equilibrium experiments were conducted at 1100 °C in air atmosphere to investigate the phase equilibria of the CaO-SiO2-Nb2O5-Fe2O3-TiO2 slag system. According to the experimental results, the liquidus surfaces of the liquid + CaTiO3 and liquid + SiO2 equilibrium coexistence regions in the CaO-SiO2-Nb2O5-5wt.% Fe2O3-TiO2 system at 1100 °C in air atmosphere were determined using interpolation and function fitting methods. Finally, the 1100 °C isothermal phase diagrams of the CaO-SiO2-Nb2O5-5 wt.% Fe2O3-TiO2 system were plotted. The composition range of liquid phase region was determined, and the positional relationships of the seven other equilibrium coexistence regions were illustrated. [ABSTRACT FROM AUTHOR]

Phase equilibria in the Al2O3–Ta2O5 system have been studied by means of CO2 laser heater, high‐speed pyrometer, X‐ray powder diffraction, and scanning electron microscopy. The liquidus and invariant reaction temperatures in the whole composition region were measured by cooling trace tests. The monotectic reaction of Liquid 1→Liquid 2 + Al2O3 was determined to be at about 1547°C, but the typical microstructures for the miscibility gap were not directly observed in our experiments. The tetragonal AlTaO4 phases formed from as‐cast samples were found to congruently melt at 1669°C, and they could maintain stability during the cooling process but would gradually transform into orthorhombic and monoclinic polymorphs after heat treatment. Two eutectic reactions of Liquid → Al2O3 + T‐AlTaO4 and Liquid → T‐AlTaO4 + β‐Ta2O5 were measured to be at 1447°C and 36.7 mol%Ta2O5 and 1513°C and 63.5 mol% Ta2O5, respectively. Due to the undercooling effect, the invariant reaction temperatures determined by this work might be preliminary and need to be verified by more accurate methods. Our experiments confirmed that doping Al2O3 in Ta2O5 phases could improve phase stability of β‐Ta2O5. Finally, thermodynamic optimization of the Al2O3–Ta2O5 system was performed based on the obtained experimental data by means of the CALPHAD method. The self‐consistent thermodynamic parameters are helpful in further efforts for construction of Al2O3–Ta2O5‐based multicomponent thermodynamic database and the development of alumina–tantala‐based materials. [ABSTRACT FROM AUTHOR]

This study examined the stability of methane hydrate at a concentration of 20 mass % in aqueous solutions of allyl and propargyl alcohols. The research determined the position of the three-phase equilibrium «alcohol solution - hydrate - gas» in the pressure range of 3.68 to 9.53 MPa. A comparison of the data revealed that the equilibrium conditions for hydrate formation for both alcohols are the same at lower pressures. However, at higher pressures, the curve for allyl alcohol deviates towards lower temperatures by 0.6°C. The study found that these alcohols act as thermodynamic inhibitors of hydrate formation. From a practical viewpoint, these systems can be used in the gas industry to prevent hydrate formation and address issues related to formed hydrates. [ABSTRACT FROM AUTHOR]

This paper conducts a computational investigation of the phase behaviour of $ \textrm{C}{\textrm{H}_4} $ C H 4 - $ \textrm{C}{\textrm{O}_2} $ C O 2 binary system, utilising the SAFT-VR Mie equation of state alongside molecular dynamics (MD) simulations. Molecular parameters for pure $ \textrm{C}{\textrm{H}_4} $ C H 4 and $ \textrm{C}{\textrm{O}_2} $ C O 2 compounds were obtained by fitting the SAFT-VR Mie EOS to vapour pressure and saturated liquid density experimental data. The research first validates the SAFT-VR Mie EOS on thermodynamic properties and vapour–liquid equilibria for different compositions, pressures, and temperatures of pure $ \textrm{C}{\textrm{H}_4} $ C H 4 , $ \textrm{C}{\textrm{O}_2} $ C O 2 , and $ \textrm{C}{\textrm{H}_4} $ C H 4 - $ \textrm{C}{\textrm{O}_2} $ C O 2 mixtures with the newly extracted parameters. The study confirms the EOS's accurate prediction of coexistence properties, including pressure, density, and phase-equilibrium curve. MD simulations were performed using the LAMMPS software package, with Mie force field parameters derived from this study for non-bonded interactions. Simulations were conducted using three other force fields (OPLS-UA, UFF, and GAFF) to compare their performance with our approach. The simulation results were compared to laboratory data, or REFPROP, in the absence of laboratory data. The results showed a relatively good agreement, indicating that combining SAFT-VR Mie EOS and MD simulations is a reliable predictive tool for designing gas processing and gas storage applications involving $ \textrm{C}{\textrm{H}_4} $ C H 4 - $ \textrm{C}{\textrm{O}_2} $ C O 2 mixtures. This approach also mitigates the need for expensive and hazardous high-pressure laboratory techniques. [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]

The phase equilibria in the Na+,K+//Cl–,NO –H2O reciprocal system in the temperature range 373–573 K were modeled using the set of parameters presented in communication I of this work. According to the results of calculations, this system has a stability region of the liquid, which boils without forming a third phase (precipitate). The change in the boiling temperature was traced for selected individual bulk compositions of the system during the gradual evaporation of water from it. In the experimental determination of the boiling points or activity of water for saturated solutions formed by the dissolution of salts with opposite cations and anions, one should take into account that the composition of such solutions will change with any changes in the total concentrations of the salts of the system if a salt other than the one used for mixing appears in the precipitate. [ABSTRACT FROM AUTHOR]

Partial reoptimization of the parameters of the Wang–Gruszkiewicz model has been performed, which made it possible to describe phase equilibria in boundary ternary systems that form a Na+,K+//Cl–,NO –H2O reciprocal system near the boiling temperatures. The regions of stability of the liquid phase, i.e., the compositions of solutions whose boiling does not lead to isolation of a solid phase were determined. At definite ratios of the amounts of sodium and potassium nitrates in the NaNO3–KNO3–H2O system, the vapor pressure of water over the saturated solutions equals the atmospheric pressure at two different temperatures. [ABSTRACT FROM AUTHOR]

Using the homogenizing annealing method and X-ray powder diffraction, it was shown that in the quasi-ternary PrOx–CoO–NiO system at 1373 K in air, two series of solid solutions are formed: PrCo NixO3 (0.0 ≤ x ≤ 0.4) with the orthorhombically distorted perovskite structure and Pr4Ni CoyO (0.7 ≤ y ≤ 1.5) with the Ruddlesden–Popper type structure with n = 3. The oxygen content in both series of solid solutions is close to stoichiometric. It is assumed that Ni2+ ions are predominantly located in octahedra located in the middle of the perovskite block, while Ni3+ and Co3+ ions are in octahedra adjacent to the rock salt layers. Phase diagrams of the PrOx–CoOx and PrOx–NiO systems were constructed in "T–composition" coordinates in air using literature data. [ABSTRACT FROM AUTHOR]

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 Fe2O3-TiO2-V2O5 system at 1200°C 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 TiO2 and V2O5 contents with the Fe2O3 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. [ABSTRACT FROM AUTHOR]

Knowledge of the phase equilibria in the MgO–CaO–SiO2–Al2O3 slag system is crucial for the nickel laterite smelting process. The phase equilibria of this slag system were experimentally investigated, focusing on the olivine and tridymite/cristobalite primary phase fields, using high-temperature equilibration and quenching methods, followed by Scanning Electron Microscopy–Energy Dispersive X-Ray analysis. The phase equilibria of the MgO–CaO–SiO2 slag system at 1400 °C and 1500 °C were first determined in the absence of ferronickel alloy. The phase equilibria between 1400 °C, 1450 °C, and 1500 °C were then determined under a reducing condition, i.e., at equilibrium with ferronickel alloy and solid carbon. Finally, the effect of Al2O3 addition on the liquidus and solidus compositions in the slag system under the reducing condition was investigated at 1400 °C and 1450 °C. Comparisons between the experimentally constructed diagram, previous data, and FactSage-predicted phase diagrams have been provided and discussed. The present study identified the liquid slag both in the absence and presence of ferronickel alloy and solid carbon, as well as in the presence of Al2O3 impurity, within the formation boundaries of olivine and tridymite/cristobalite solids. Identifying the liquid slag area is essential to ensure that the nickel laterite smelting slag can be tapped from the furnace. [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]

Rhyolitic tuffs range widely in their crystal contents from nearly aphyric to crystal-rich, and their crystal cargoes inform concepts of upper crustal magma reservoirs. The Earthquake Flat pyroclastics (Okataina Volcanic Center, Taupo Volcanic Zone, New Zealand) are 10 km3 of rhyolitic tuffs with abundant (~ 40 vol.%) plagioclase and quartz, minor biotite, hornblende, and orthopyroxene, and accessory Fe-Ti oxides, apatite, and zircon, set in high-silica rhyolitic glass. Major minerals form large, euhedral phenocrysts and abundant glomerocrysts with few disequilibrium textures excepting some faintly resorbed quartz. Plagioclase phenocrysts have thick rims of nearly constant composition near An30, and hornblende is weakly zoned or unzoned. The abundant and texturally complex mineral assemblage contrasts with the nearby (~ 25 km), nearly synchronous, but more voluminous and crystal-moderate rhyolite tuffs from Rotoiti caldera. New H2O-saturated phase-equilibria results on the erupted Earthquake Flat melt (glass) determine its co-saturation with the partial phenocryst assemblage of plagioclase, quartz, biotite, and Fe-Ti oxides at: 140 MPa, 755 ºC. These closely approximate the conditions of the pre-eruptive magma body assuming it was saturated with nearly pure H2O and at an fO2 of ~ Ni–NiO. Absence of hornblende and orthopyroxene from the synthesized assemblages may result from those minerals being in a peritectic reaction relation with melt to produce biotite, so they would not grow from the liquid used as starting material. Experimental results on Rotoiti rhyolite (Nicholls et al. 1992) show that the two bodies resided at similar pressures, temperatures, and fO2s. Lower crystal abundance of the Rotoiti tuffs may result from slight compositional differences. We interpret that the Earthquake Flat pyroclastics were sourced from the crystal-rich periphery of a mushy reservoir system with the Rotoiti occupying a more melt-rich central location. Uncertain is whether this was a single intrusion zoned continuously in crystallinity, or discrete adjacent intrusions, but our results illustrate and quantify complexities of magma storage across relatively short distances. [ABSTRACT FROM AUTHOR]

The phase equilibria of the La-Co-Zr ternary system at 873 K and 1073 K were studied for the first time using equilibrated alloys employing scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and x-ray diffraction (XRD). The crystal structures of the formed phases in La-Co-Zr alloys annealed at 873 K and 1073 K were identified through Rietveld refinement of the XRD results. The SEM-EDS and XRD results reveal that no ternary intermetallic compounds were detected in the La-Co-Zr ternary system and the binary intermetallic compound La5Co19 was not observed in the La-Co binary system. The solid solubility of the third element in the binary La-Co and Co-Zr intermetallic compounds was measured by EDS composition measurements. It was found that the maximum solid solubility of Zr in LaCo5 and LaCo13 is 1.8 and 4.0 at.% at 1073 K and it is 2.3 and 4.7 at.% at 873 K, respectively, while the maximum solid solubility of La in Co23Zr6 and Co2Zr is 1.3 and 1.6 at.% at 873 K and it is 3.8 and 6.1 at 1073 K. Furthermore, the solid solubility of Zr and La in the other La-Co and Co-Zr intermetallic compounds is negligible. Finally, the La-Co-Zr ternary isothermal sections at 873 K and 1073 K were established. [ABSTRACT FROM AUTHOR]

The phase equilibria of the Er-Al-Zr ternary system at 500 °C were investigated using a combination of electron probe microanalyzer and x-ray diffraction. The microstructure and diffraction peaks were analyzed to determine the phases and compositions of Er-Al-Zr ternary system. Based on the experimental results, the isothermal phase diagram of the Er-Al-Zr ternary system consists of 14 three-phase equilibrium regions, 15 two-phase equilibrium regions, and 13 stable binary compounds, but no ternary compounds were detected. The solubility of Er in the Al2Zr, Al3Zr2, AlZr, Al3Zr4, Al2Zr3 is 9.9, 5.3, 9.0, 12.4, 6.7 at.%, respectively. The present work could be important for alloy design of Al-based alloys and thermodynamic analysis of the Er-Al-Zr ternary system. [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]

In the present study, the phase equilibria in the ternary system La2O3-ZrO2HfO2 have been studied in the whole concentration range. In the course of the study, isothermal sections of the phase diagram of the system were constructed at temperatures of 1500 and 1250 °C. The obtained results indicate the no new phase formation in the studied system. It was found that in the La2O3-ZrO2HfO2 ternary system at temperatures of 1500 and 1250 °C, solid solutions are formed on the basis of monoclinic (M, space group P21/C) HfO2 and tetragonal (T, space group P42/nmc) modifications of ZrO2, solid solutions based on a hexagonal modification (A, space group P3m1) of La2O3, and an ordered phase with a pyrochlore-type structure of La2Zr2О7 (La2Hf2О7) (Py, space group Fd-3 m). The system studied is characterized by the formation of a continuous series of solid solutions with a pyrоchlore-type structure. A decrease in temperature from 1500 °C to 1250 °C leads to the shift of the three-phase region, containing solid solutions based on a pyrochlore-type structure of Ln2Zr2О7 (Ln2Hf2О7), monoclinic M-HfO2, and tetragonal T-ZrO2, towards the concentration area with higher ZrO2 content and also to an increase in the extent of the solid solution based on the monoclinic modification M-HfO2.

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-NbCr2 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-NbCr2 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-NbCr2 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.

The critical unwinding field was studied theoretically using Landau-Ginzburg free energy model of pure antiferroelectric liquid crystals (AFLC), influenced by flexoelectric effect in presence of spin–spin interaction. In this study, we constructed an appropriate Landau free energy using the flexoelectric effect and spin–spin interaction in AFLC. Using the Landau-Ginzburg equation of azimuthal angles, we observed that the flexoelectric effect in AFLC did not make any difference in the critical unwinding for both the cases when elastic constant was keeping as constant or inter-layer interaction strength was keeping as constant. But for AFLC in presence of spin–spin interaction, the reverse electric field and the modified elastic constant were created a significant change in the critical unwinding field in compare to others. [ABSTRACT FROM AUTHOR]