Thermodynamic calculations of heterogeneous equilibria in the hydrothermal systems

TitleThermodynamic calculations of heterogeneous equilibria in the hydrothermal systems
Publication TypeJournal Article
Year of Publication1993
AuthorsPingfang, S, S.K., S, Eriksson, G
JournalProceedings of the 4th International Symposium on Hydrothermal Reactions, Institut Lorrain des Geosciences
Keywordschemsage, geochemistry
Abstract

Thermodynamic calculations of the heterogeneous reactions in the multicomponent system are best done by using the technique of Gibbs free energy minimization. A review of the thermodynamic models and databases on supercritical fluids, aqueous solutions, solids and solid solutions, used for such calculations, especially for studying the geohemical processes of hydrothermal systems, is presented here. The reviewed data are used with a modified version of ChemSage, which uses the same models for aqueous and hydrothermal solutions as those used in SUPCRT92. Specific problems involved in the geochemical processes of hydrothermal and/or metamorphic systems, which can be investigated by this approach, are discussed. Some examples of thermodynamic simulations of heterogeneous phase equilibria to investigate the geochemical processes involved in the hydrothermal evolution of the Cigar Lake uranium deposit are presented.