Vapour Pressure of Ternary LiClNaClAlCl<sub>3</sub> Melts

Knapstad, B.; Linga, Hogne; Øye, H. A.

doi:10.1002/bbpc.19810851211

Cited by 7 publications

(2 citation statements)

References 8 publications

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“…In some of the experiments, corrections of the measured vapor pressure had to be done due to changes of the composition during a run. The correction method applied by Knapstad, Linga, and Øye was used with some modifications.…”

Section: Methodsmentioning

confidence: 99%

Structure and Thermodynamics of NaF−AlF₃ Melts with Addition of CaF₂ and MgF₂

et al. 1996

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The NaF-AlF(3) system with additions of CaF(2) and MgF(2) has been studied with Raman and vapor pressure measurements for 3 >/= CR (NaF/AlF(3) molar ratio) >/= 1 and up to 50 mol % additive. The results show that the binary melt can be described using the two equilibria AlF(6)(3)(-) = AlF(6)(2)(-) + F(-) and AlF(5)(2)(-) = AlF(4)(-) + F(-) with equilibrium constants 0.25 and 0.05, respectively, at 1293 K. Both reactions have positive reaction enthalpies. The first equilibrium is strongly shifted to the right resulting in a melt mixture with very low AlF(6)(3)(-) concentrations even at the Na(3)AlF(6) composition. Evidence for nonideal mixing of anions was found. For the ternaries, models based on Raman data are presented and compared with vapor pressure measurements. Good agreement is observed when association between the additives, CaF(2) or MgF(2), with the AlF(5)(2)(-) ions in the melt was considered. This association could be experimentally observed through a band broadening and a slight shift in the AlF(5)(2)(-) band frequency. Our vapor pressures and Raman data both indicate that MgF(2) clearly acts as an acid when added to NaF-AlF(3) melts of any composition. When CaF(2) is added, a slight decrease of vapor pressure occurs. Raman data indicate a decrease of AlF(4)(-) concentration, corresponding to a dissociation of CaF(2) with liberation of F(-) ions. All these results are, however, very much dependent on the initial melt composition. These data are explained in terms of acid-base, dilution, and association reactions of the solute with the solvent.

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Section: Methodsmentioning

confidence: 99%

Structure and Thermodynamics of NaF−AlF₃ Melts with Addition of CaF₂ and MgF₂

et al. 1996

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“…Figures 9 and 10 give the total pressure and composition of the vapor phase. [19] corresponding EMF values from the present model with [19] earlier models for the binary systems and using a FloodMuan type model. lnKϭ X LiCl X LiCl ϩX NaCl lnK Li ϩ X NaCl X LiCl ϩX NaCl lnK Na [23] for the equilibrium…”

Section: Alkcl-alcl 3 (Basic Melts)mentioning

confidence: 99%

The power of thermodynamic modeling; examples from molten halide mixtures

Øye

2000

Metall Mater Trans B

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Although thermodynamics is the science of energy transformations, structural models have often been very useful to describe and predict thermodynamic properties. An early example is Flood and Urnes' description of the KCl-MgCl 2 phase diagram on the KCl side by assuming the presence of MgCl 2Ϫ 4 . Examples will be given from aluminium chloride-alkali chloride systems where total vapor pressure of binary systems was determined. Through modeling, it was possible to describe the liquid phase, composition of the gas phase, and phase diagrams for binary and ternary systems. Determination of thermodynamic properties, which was nearly inaccessible for experimental determination, was also accomplished through modeling.

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Vapour Pressure of Molten Acidic Potassium Chloride‐Aluminium Chloride‐Aluminium Chloride Monoammine Mixtures

Nakamura¹,

Østvold²,

Øye³

1986

Ber Bunsenges Phys Chem

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The acidic KCl‐AlCl3NH3AlCl3 melt has been studied by vapour pressure measurements, vapour condensation measurements and mass spectrometry. ‐ Vapour pressures were measured by the boiling point method. The total vapour pressure above AlCl3NH3(1) is given by the expression: ln(P/atm) = ‐8660 (T/K)−1 + 12.69. The partial pressure may be expressed by ln (P AlCl 3NH3/atm) ∼ ‐8589 (T/K)−1 + 12.53. ‐ Together with mass spectrometric experiments the composition of the equilibrium vapour was determined by direct condensation of the boiled‐off vapour above the KCl‐AlCl3NH3‐AlCl3 melts. The existence of the species Al2Cl6, AlCl3, AlCl3NH3 and Al2Cl6NH3 were confirmed. ‐ Thermodynamic properties of the ternary melts were described through thermodynamic model calculations based on the following equilibria. The activities of Al2Cl6 calculated at a given temperature were in good agreement with experimental data (SD in the fit was ± 2.1%). The calculated total pressures agreed fairly well with experimental pressures (SD = ± 8.5%) taking also into account data which was not used for modelling.

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Vapour Pressure of Ternary LiClNaClAlCl₃ Melts

Cited by 7 publications

References 8 publications

Structure and Thermodynamics of NaF−AlF₃ Melts with Addition of CaF₂ and MgF₂

Structure and Thermodynamics of NaF−AlF₃ Melts with Addition of CaF₂ and MgF₂

The power of thermodynamic modeling; examples from molten halide mixtures

Vapour Pressure of Molten Acidic Potassium Chloride‐Aluminium Chloride‐Aluminium Chloride Monoammine Mixtures

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Vapour Pressure of Ternary LiClNaClAlCl3 Melts

Cited by 7 publications

References 8 publications

Structure and Thermodynamics of NaF−AlF3 Melts with Addition of CaF2 and MgF2

Structure and Thermodynamics of NaF−AlF3 Melts with Addition of CaF2 and MgF2

The power of thermodynamic modeling; examples from molten halide mixtures

Vapour Pressure of Molten Acidic Potassium Chloride‐Aluminium Chloride‐Aluminium Chloride Monoammine Mixtures

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Vapour Pressure of Ternary LiClNaClAlCl₃ Melts

Structure and Thermodynamics of NaF−AlF₃ Melts with Addition of CaF₂ and MgF₂

Structure and Thermodynamics of NaF−AlF₃ Melts with Addition of CaF₂ and MgF₂