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Abdulagatov, Ilmutdin M.; Dvoryanchikov, V. I.; Kamalov, A. N.; Абрамова, Е. Г.

doi:10.1023/a:1021784231509

Cited by 6 publications

(6 citation statements)

References 9 publications

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“…This paper is concerned with the high-temperature phase behavior of aqueous solutions of sodium sulfate and, to a lesser extent, sodium carbonate, as derived from recent measurements of the isochoric heat capacities of these systems by Abdulagatov et al , We interpret these features in terms of the solid−liquid−vapor phase diagram and show their consistency with earlier PVTx , phase boundary, and three-phase data from Khaibullin and Novikov. , These data are referred to as Kh 3,4 data. Aqueous sodium sulfate has a complex phase diagram.…”

Section: Introductionmentioning

confidence: 57%

“…It is the purpose of this paper to interpret the locations of the phase boundaries encountered from 350 K up to the critical end point, as they manifest themselves in peaks and jumps in the heat capacity data for aqueous sodium sulfate . We also analyze data near the critical end point of aqueous sodium carbonate . Satisfactory consistency with Khaibullin's PVTx data for the saturated liquid and for the three-phase line of aqueous sodium sulfate is demonstrated.…”

Section: Introductionmentioning

confidence: 82%

“…In attributing observed peaks or jumps in the C vx − T curve to a particular type of phase transition, use was made of existing information on the solubility curve or on the three-phase curve: namely, data on the concentration of the liquid solution saturated with salt while in equilibrium with vapor, published by Kh 3,4 and by others; see the compilation by Zdanovsky et al The data by Abdulagatov et al , analyzed here were reported on the ITS-90 temperature scale. The temperatures reported by Kh, , and in the Zdanovsky et al compilation, were mostly recorded on the IPTS-48 and IPTS-68 scales.…”

Section: Appearance Of a Solid Phase In Liquid−vapor Conditionsmentioning

confidence: 99%

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Vapor−Liquid−Solid Phase Transitions in Aqueous Sodium Sulfate and Sodium Carbonate from Heat Capacity Measurements near the First Critical End Point. 2. Phase Boundaries

2000

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The constant volume, constant composition heat capacity data for aqueous sodium sulfate show several interesting features: one peak or step when solid salt first precipitates and, on further heating, a λ-shaped peak when the vapor- or liquid-phase disappears. These features are interpreted in terms of the solid−liquid−vapor phase diagram, and their consistency is shown with earlier PVTx, phase boundary, and three-phase data from the literature. New data are presented on the density of liquid solutions saturated with respect to the vapor. New liquid compositions or densities supplement the three-phase data available in the literature, and new fluid densities are reported near the critical end point. For aqueous Na2SO4, we find T cep = (648.2 ± 0.2) K, and for aqueous Na2CO3, T cep = (649.0 ± 0.2) K. The present heat capacity data, as well as recent data for aqueous sodium carbonate, have sufficient resolution to distinguish, for the first time, the temperature of the critical end points in aqueous sodium sulfate and aqueous sodium carbonate from the critical temperature of pure water, T c = (647.1 ± 0.1) K.

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Section: Introductionmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 82%

Section: Appearance Of a Solid Phase In Liquid−vapor Conditionsmentioning

confidence: 99%

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Vapor−Liquid−Solid Phase Transitions in Aqueous Sodium Sulfate and Sodium Carbonate from Heat Capacity Measurements near the First Critical End Point. 2. Phase Boundaries

2000

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“…Those obtained in a cooling ramping mode are marked with a superscript C in Table . The data for sodium carbonate, which will be referred to in Part 2 of this series, were published in Abdulagatov et al…”

Section: Methodsmentioning

confidence: 99%

“…The solid phase extends above the critical point of water; thus, cutting off the saltwater critical line in a critical end point. This so-called Type-2 solid−liquid−vapor phase behavior, typical for sodium sulfate, sodium carbonate (Abdulagatov et al), and many other salts poorly soluble in water, will be described in more detail in Valyashko et al, Part 2 of this series.…”

Section: Introductionmentioning

confidence: 99%

Vapor−Liquid−Solid Phase Transitions in Aqueous Sodium Sulfate and Sodium Carbonate from Heat Capacity Measurements near the First Critical End Point. 1. Sodium Sulfate

2000

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Heat capacities at constant volume and composition are reported for aqueous sodium sulfate for three compositions, 1 mass %, 5 mass %, and 10 mass %, respectively, and along 19 isochores, from 250 kg‚m -3 to 1073 kg‚m -3 in the temperature range from 350 K to 670 K. In the range from 630 K to 650 K, many of these isochores display two features in the heat capacity as a function of the temperature: one peak or step when solid salt first precipitates and, on further heating, a λ-shaped peak when the vapor-or liquid-phase disappears. In Part 2 of this paper, these features will be interpreted.

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One‐ and two‐phase isochoric heat capacity measurements of aqueous solution of nacl near the critical point of pure water

et al. 2000

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here is a very important theoretical aspect to near-critical and supercritical phenomena in ionic systems such as H20+NaCI T For this system, the Pc-x and Tc-x critical lines show rapid changes in slope near the critical point of pure water (Povodyrev et at., 1998). The derivatives dTc/dx and dPc/dx govern the thermodynamic (crossover) behaviour of fluid mixtures near the critical point of one component (Chang e t al., 1984;Kiselev et al., 1991; Levelt Sengers, 1993;Povodyrev et al., 1997). More precise experimental C , data are needed to confirm the basic ideas of modern crossover theory of critical phenomena in ionic systems. Therefore, our new experimental data C , for H,O+NaCI near the critical point of pure water may prove to be very important for the development of new theoretical equations of state which will more correctly predict the thermodynamic behaviour of ionic solutions near the solvent critical point (pure water) and improved existing models for aqueous electrolytes.A lot of attention has been focused on the system H20+NaCI because of its fundamental importance to the understanding of electrolyte behaviour and because of its importance in many geological and industrial processes. Thermodynamic properties of the H,O+NaCI system are required for the understanding of many hydrothermal processes. The development of an equation of state depends on experimental data, from which empirical parameters can be obtained. NaCl is a good example of a 1 :1 charge-type electrolyte. Theoretical modelling of the H,O+NaCI system will serve as an example for other ionic systems of 1 :1 charge-type electrolytes.The two-phase region of H20+NaCI solutions has been of particular interest because the phase equilibria properties are important in many hydrothermal processes Pitzer, 1985, 1989;Delany et al., 1987). Aqueous NaCl solutions at high temperatures and high pressures are encountered in deep earth, ocean and in electric power plants where an aqueous salt solution is used as the heat transfer fluid. Understanding various geochemical and industrial processes requires a thorough knowledge of thermodynamic properties of aqueous electrolyte solutions such as H20+NaCI.The main objective of the paper is to obtain new reliable experimental isochoric heat capacity data for NaCl in near subcritical and near supercritical water which can be used as a prospective medium in the new

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Cited by 6 publications

References 9 publications

Vapor−Liquid−Solid Phase Transitions in Aqueous Sodium Sulfate and Sodium Carbonate from Heat Capacity Measurements near the First Critical End Point. 2. Phase Boundaries

Vapor−Liquid−Solid Phase Transitions in Aqueous Sodium Sulfate and Sodium Carbonate from Heat Capacity Measurements near the First Critical End Point. 2. Phase Boundaries

Vapor−Liquid−Solid Phase Transitions in Aqueous Sodium Sulfate and Sodium Carbonate from Heat Capacity Measurements near the First Critical End Point. 1. Sodium Sulfate

One‐ and two‐phase isochoric heat capacity measurements of aqueous solution of nacl near the critical point of pure water

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