Thermodynamics of concentrated electrolyte mixtures and the prediction of mineral solubilities to high temperatures for mixtures in the system Na-K-Mg-Cl-SO/sub 4/-OH-H/sub 2/O

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

DOI:https://doi.org/10.1016/0016-7037(87)90295-X· OSTI ID:5064873

Pabalan, R T; Pitzer, K S

Mineral solubilities in binary and ternary electrolyte mixtures in the system Na-K-Mg-Cl-SO/sub 4/-OH-H/sub 2/O are calculated to high temperatures using available thermodynamic data for solids and for aqueous electrolyte solutions. Activity and osmotic coefficients are derived from the ion-interaction model of Pitzer (1973, 1979) and co-workers, the parameters of which are evaluated from experimentally determined solution properties or from solubility data in binary and ternary mixtures. Excellent to good agreement with experimental solubilities for binary and ternary mixtures indicate that the model can be successfully used to predict mineral-solution equilibria to high temperatures. Although there are currently no theoretical forms for the temperature dependencies of the various model parameters, the solubility data in ternary mixtures can be adequately represented by constant values of the mixing term Phi/sub ij/ and values of Phi/sub ijk/ which are either constant or have a simple temperature dependence. Since no additional parameters are needed to describe the thermodynamic properties of more complex electrolyte mixtures, the calculations can be extended to equilibrium studies relevant to natural systems. Examples of predicted solubilities are given for the quaternary system NaCl-KCl-MgCl/sub 2/-H/sub 2/-O.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5064873
• Journal Information: Geochim. Cosmochim. Acta; (United States), Vol. 51:9
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ELECTROLYTES
GEOCHEMISTRY
THERMODYNAMIC PROPERTIES
MINERALS
DISSOLUTION
SOLUBILITY
CHLORINE
FORECASTING
MAGNESIUM
MATHEMATICAL MODELS
MIXTURES
POTASSIUM
SODIUM
SULFATES
ALKALI METALS
ALKALINE EARTH METALS
CHEMISTRY
DISPERSIONS
ELEMENTS
HALOGENS
METALS
NONMETALS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SULFUR COMPOUNDS
580400* - Geochemistry- (-1989)