scholarly journals A New Density Model of Quartz Solubility in H2O-CO2-NaCl Ternary Systems up to High Temperatures and High Pressures

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Weiping Deng ◽  
Qing Wei ◽  
Xuan Liu
Keyword(s):  
Experimental Data ◽  
Molar Volume ◽  
Partial Molar Volume ◽  
High Pressures ◽  
Pure Water ◽  
Molar Fraction ◽  
Density Model ◽  
Liquid Region ◽  
Lower Accuracy ◽  
Quartz Solubility

A novel density model for computing quartz solubility in H2O-CO2-NaCl hydrothermal fluids applicable to wide ranges of temperature and pressure is proposed. Based on the models of Akinfiev and Diamond (2009) and Wei et al. (2012), the effective partial molar volume of water ( V H 2 O ∗ ) is replaced by the partial molar volume of water ( V ¯ H 2 O ) by implementing an empirical correction, and water molar fraction ( x H 2 O ) is modified with water activity ( a H 2 O ), in addition to a series of changes to the model coefficient forms. The absolute values of averaged relative deviation of this model compared to the experimental data sets in pure water, H2O-CO2, and H2O-NaCl solutions are 5.74%, 6.69%, and 7.09%, respectively, which are better than existing models in the literature. The model can be reliably used for computing quartz solubilities in pure water from 0°C to 1000°C, from 0 bar to 20,000 bar, and in CO2- and/or NaCl-bearing solutions from 0°C to 1000°C, from 0 bar to 10,000 bar (with slightly lower accuracy at 5000-10,000 bar in H2O-NaCl systems) in the single liquid region. Moreover, the trends and overall ranges of this model may probably be more accurate in the H2O-CO2-NaCl fluid mixtures compared to the limited experimental data. In addition, a bisection algorithm for deriving the isopleths of quartz solubilities based on this new model is first proposed, and application perspectives are discussed for various geologic settings including subduction zone, lower crust-upper mantle, migmatite, pegmatite, porphyry, and orogenic deposits.

High Pressure Carbon Behavior Induced from Carbide Hugoniots

1997 ◽  
Vol 499 ◽  
Author(s):  
T. Sekine ◽  
E. Takazawa ◽  
T. Kobayashi
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Molar Volume ◽  
Partial Molar Volume ◽  
High Pressures ◽  
Diamond Structure ◽  
Structural Variations ◽  
Diamond Phase ◽  
Type Carbide ◽  
Diamond Type

ABSTRACTInvestigations of Hugoniots the diamond-type carbides(various SiC) and NaCl-type carbides such as TiC give some insights into the high-pressure carbon behaviors. The experimental results of phase transitions of a-SiC and β-SiC, together with those of diamond-structure Si, imply that the candidate as post-diamond phase has sixfold coordination and that a possible transition pressure is about 1–2 TPa. The NaCl-type carbide Hugoniots indicate that sixfold coordinated C is very stable at high pressures. The partial molar volume of carbon in the NaCl-type carbides ranges between 1.4 to 2.6 cnvVg-atom C at 1 atm and reaches about 2.8 cm3/g-atom C at 100 GPa. Taking into account structural variations of the corresponding metals, the volume of the sixfold coordinated C is estimated to be 1.7 cm3/g-atom C, about half of that of diamond, and the post-diamond phase appears to be extremely hard.

Propriétés volumiques du nitrate d'éthylammonium fondu à 298 K et de ses mélanges avec l'eau

1985 ◽  
Vol 63 (3) ◽  
pp. 565-570 ◽  
Author(s):  
M. Hadded ◽  
M. Biquard ◽  
P. Letellier ◽  
R. Schaal
Keyword(s):  
Molar Volume ◽  
Salt Water ◽  
Pure Water ◽  
Molar Fraction ◽  
Partial Molar Volumes ◽  
Intrinsic Volume ◽  
Ethylammonium Nitrate ◽  
Actual Volume ◽  
Concentrated Solution ◽  
Fused Salt

Partial molar volumes of water and ethylammonium nitrate EAN are determined accurately in all water–EAN mixtures, between pure water and pure fused salt at 298 K. It has been found that the partial molar volume of water decreases linearly with molar fraction of salt, x, in concentrated solution of EAN (C > 2 mol L−1, x > 0.04). The main thermodynamic relations are established to describe the volumetric behaviour of salt, water, and solution. It has been shown that the intrinsic volume of salt can be identified roughly with the molar volume of the pure fused salt and the value of apparent molar volume of water with the actual volume of water in solution.

scholarly journals Behavior and properties of water in silicate melts under deep mantle conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bijaya B. Karki ◽  
Dipta B. Ghosh ◽  
Shun-ichiro Karato
Keyword(s):  
Electrical Conductivity ◽  
Molar Volume ◽  
Water Solution ◽  
Pure Water ◽  
Electrical Conductance ◽  
Water Structure ◽  
Bulk Water ◽  
Silicate Melts ◽  
Pressure Regime ◽  
Low Pressures

AbstractWater (H2O) as one of the most abundant fluids present in Earth plays crucial role in the generation and transport of magmas in the interior. Though hydrous silicate melts have been studied extensively, the experimental data are confined to relatively low pressures and the computational results are still rare. Moreover, these studies imply large differences in the way water influences the physical properties of silicate magmas, such as density and electrical conductivity. Here, we investigate the equation of state, speciation, and transport properties of water dissolved in Mg1−xFexSiO3 and Mg2(1−x)Fe2xSiO4 melts (for x = 0 and 0.25) as well as in its bulk (pure) fluid state over the entire mantle pressure regime at 2000–4000 K using first-principles molecular dynamics. The simulation results allow us to constrain the partial molar volume of the water component in melts along with the molar volume of pure water. The predicted volume of silicate melt + water solution is negative at low pressures and becomes almost zero above 15 GPa. Consequently, the hydrous component tends to lower the melt density to similar extent over much of the mantle pressure regime irrespective of composition. Our results also show that hydrogen diffuses fast in silicate melts and enhances the melt electrical conductivity in a way that differs from electrical conduction in the bulk water. The speciation of the water component varies considerably from the bulk water structure as well. Water is dissolved in melts mostly as hydroxyls at low pressure and as –O–H–O–, –O–H–O–H– and other extended species with increasing pressure. On the other hand, the pure water behaves as a molecular fluid below 15 GPa, gradually becoming a dissociated fluid with further compression. On the basis of modeled density and conductivity results, we suggest that partial melts containing a few percent of water may be gravitationally trapped both above and below the upper mantle-transition region. Moreover, such hydrous melts can give rise to detectable electrical conductance by means of electromagnetic sounding observations.

Experimental data and thermodynamics modeling (PC-SAFT EoS) of the {CO2 + chloroform + PHBV} system at high pressures

2021 ◽  
Vol 170 ◽  
pp. 105140
Author(s):  
Rogerio Favareto ◽  
Paulo Cardozo Carvalho de Araujo ◽  
Isaac Dias Bezerra ◽  
Andreia Fátima Zanette ◽  
Pedro Felipe Arce ◽  
...  
Keyword(s):  
Experimental Data ◽  
High Pressures ◽  
Thermodynamics Modeling

Experimental and Numerical Study of Methanol-Water Mixture Single-Phase Heat Transfer in a Micro-Channel Heat Sink

2012 ◽  
Author(s):  
Chun K. Kwok ◽  
Matthew M. Asada ◽  
Jonathan R. Mita ◽  
Weilin Qu
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Sink ◽  
Single Phase ◽  
Numerical Study ◽  
Pure Water ◽  
Molar Fraction ◽  
Water Mixture ◽  
Micro Channel ◽  
Numerical Predictions

This paper presents an experimental study of single-phase heat transfer characteristics of binary methanol-water mixtures in a micro-channel heat sink containing an array of 22 microchannels with 240μm × 630μm cross-section. Pure water, pure methanol, and five methanol-water mixtures with methanol molar fraction of 16%, 36%, 50%, 63% and 82% were tested. Key parametric trends were identified and discussed. The experimental study was complemented by a three-dimensional numerical simulation. Numerical predictions and experimental data are in good agreement with a mean absolute error (MAE) of 0.87%.

Sign in / Sign up

Export Citation Format

Share Document