Chemical equilibrium algorithm for highly non-ideal multiphase systems: free energy minimization
Journal Article
·
· Geochim. Cosmochim. Acta; (United States)
A method is presented for calculating equilibrium phase assemblages in very nonideal systems. It may be applied to any system for which a thermodynamically consistent model of the free energy which satisfies the usual Maxwell relations and convexity criterion is available. The algorithm minimizes the Gibbs free energy by independently choosing stable reaction directions. The procedure is described in detail and various numerical problems encountered and strategies for dealing with them are discussed. It will be shown that the necessary and sufficient conditions for solution phase selection may be derived from the values of the Lagrange multipliers corresponding to constraints on phases that are not present in the system. The method for evaluating the solution phase Lagrangian multipliers and choosing the optimum composition with which to bring the new solution phase into the system involves a separate constrained minimization problem. This method is sufficiently general so that the correct phase assemblage is chosen free from external control. Special procedures for adding and removing phases including solution phases are also described.
- Research Organization:
- Univ. of California, San Diego, La Jolla (USA)
- DOE Contract Number:
- AC03-85SF15522
- OSTI ID:
- 6992563
- Journal Information:
- Geochim. Cosmochim. Acta; (United States), Journal Name: Geochim. Cosmochim. Acta; (United States) Vol. 51:5; ISSN GCACA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
580400* -- Geochemistry-- (-1989)
ALGORITHMS
BRINES
CHEMISTRY
DIFFERENTIAL EQUATIONS
ENERGY
EQUATIONS
EQUATIONS OF STATE
EQUILIBRIUM
FREE ENERGY
GEOCHEMISTRY
LAGRANGE EQUATIONS
MAGMA
MATHEMATICAL LOGIC
MATHEMATICAL MODELS
MAXWELL EQUATIONS
PARTIAL DIFFERENTIAL EQUATIONS
PARTICLE MODELS
PHASE SHIFT
PHASE STUDIES
PHYSICAL PROPERTIES
STATISTICAL MODELS
THERMODYNAMIC ACTIVITY
THERMODYNAMIC MODEL
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
580400* -- Geochemistry-- (-1989)
ALGORITHMS
BRINES
CHEMISTRY
DIFFERENTIAL EQUATIONS
ENERGY
EQUATIONS
EQUATIONS OF STATE
EQUILIBRIUM
FREE ENERGY
GEOCHEMISTRY
LAGRANGE EQUATIONS
MAGMA
MATHEMATICAL LOGIC
MATHEMATICAL MODELS
MAXWELL EQUATIONS
PARTIAL DIFFERENTIAL EQUATIONS
PARTICLE MODELS
PHASE SHIFT
PHASE STUDIES
PHYSICAL PROPERTIES
STATISTICAL MODELS
THERMODYNAMIC ACTIVITY
THERMODYNAMIC MODEL
THERMODYNAMIC PROPERTIES
THERMODYNAMICS