Phase relations in the system NaCl-KCl-H/sub 2/O. III. Solubilities of halite in vapor-saturated liquids above 445/sup 0/C and redetermination of phase equilibrium properties in the system NaCl-H/sub 2/O to 1000/sup 0/C and 1500 bars

Journal Article · Wed Jul 01 00:00:00 EDT 1987 · Geochim. Cosmochim. Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(87)90185-2· OSTI ID:7252235

Chou, I

Halite solubilities along the three-phase curve in the binary system NaCl-H/sub 2/O determined by differential thermal analysis (DTA) experiment can be represented by the discussed equation where 447 less than or equal to T less than or equal to 800/sup 0/C. Even though these halite solubilities are up to approx. 7 wt.% higher than those reported in literature, extrapolated values at temperatures below 447/sup 0/C merge with the literature values. It is considered that the equation adequately describes halite solubilities between 382 and 800/sup 0/C. The newly established solubility data are believed to be more reliable because they are compatible with data obtained by using synthetic fluid inclusions and with the observed DTA signals and also because they were measured in a relatively corrosion-free system. In an earlier publication the authors were puzzled greatly by multiple and rather unreproducible DTA peaks appearing during isobaric cooling at pressures below about 500 bars. These DTA signals apparently suggested that the halite liquidus swung sharply upward in temperature as pressure decreased from about 500 bars to that of the halite-saturated boiling curve. Further analysis of the data and helpful discussions with several individuals have revealed that the behavior is a consequence of the initial separation of the fluid into NaCl-poor gas and NaCl-rich liquid that failed to homogenize in the short time encompassed by the DTA experiments. The present analysis is based on extrapolations of the dP/dT slopes from pressures above 500 bars.

• Research Organization: Geological Survey, Reston, VA (USA)
• OSTI ID: 7252235
• Journal Information: Geochim. Cosmochim. Acta; (United States), Vol. 51:7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
HALITE
EQUILIBRIUM
PHASE STUDIES
SOLUBILITY
THERMODYNAMIC ACTIVITY
DIFFERENTIAL THERMAL ANALYSIS
GEOCHEMISTRY
INCLUSIONS
PHASE TRANSFORMATIONS
POTASSIUM CHLORIDES
SODIUM CHLORIDES
TEMPERATURE EFFECTS
WATER
ALKALI METAL COMPOUNDS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
HALIDE MINERALS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
MINERALS
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
SODIUM COMPOUNDS
THERMAL ANALYSIS
580400* - Geochemistry- (-1989)