Phase relations in the system NaCl-KCl-H sub 2 O: V. Thermodynamic-PTX analysis of solid-liquid equilibria at high temperatures and pressures

Journal Article · Mon Jun 01 00:00:00 EDT 1992 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(92)90190-T· OSTI ID:5035752

Sterner, S M; Pitzer, K S ^[1]; Chou, Iming ^[2]; Downs, R T ^[3]

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1. Lawrence Berkeley Lab., CA (United States)
2. Geological Survey, Reston, VA (United States)
3. Virginia Polytechnic Inst. and State Univ., Blacksburg (United States)

The Gibbs energies of mixing for NaCl-KCl binary solids and liquids and solid-saturated NaCl-KCl-H{sub 2}O ternary liquids were modeled using asymmetric Margules treatments. The coefficients of the expressions were calibrated using an extensive array of binary solvus and solidus data, and both binary and ternary liquidus data. Over the PTX range considered, the system exhibits complete liquid miscibility among all three components and extensive solid solution along the anhydrous binary. Solid-liquid and solid-solid phase equilibria were calculated by using the resulting equations and invoking the equality of chemical potentials of NaCl and KCl between appropriate phases at equilibrium. The equations reproduce the ternary liquidus and predict activity coefficients for NaCl and KCl components in the aqueous liquid under solid-saturation conditions between 673 and 1,200 K from vapor saturation up to 5 kbar. In the NaCl-KCl anhydrous binary system, the equations describe phase equilibria and predict activity coefficients of the salt components for all stable compositions of solid and liquid phases between room temperature and 1,200 K and from 1 bar to 5 kbar.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5035752
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Vol. 56:6; ISSN 0016-7037
• Country of Publication: United States
• Language: English

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15 GEOTHERMAL ENERGY
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THERMODYNAMIC PROPERTIES
EQUATIONS
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FREE ENTHALPY
LIQUIDS
MIXING HEAT
MIXTURES
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POTASSIUM CHLORIDES
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TEMPERATURE RANGE 1000-4000 K
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ENERGY
ENTHALPY
FLUIDS
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HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
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152001* - Geothermal Data & Theory- Properties of Aqueous Solutions
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