A DATABANK OF THE STABILITY CONSTANTS OF COMPLEX COMPOUNDS OF RARE-EARTH ELEMENTS IN A WIDE RANGE OF TEMPERATURES, PRESSURES, AND SOLUTION COMPOSITIONS
G. R. Kolonin, K. G. Morgunov, and G. P. Shironosova
Keywords: Rare-earth elements, dissolved particles, complex formation, hydroxocomplexes, carbonate complexes, fluorocomplexes, databank, hydrothermal solutions, thermodynamic modeling
Pages: 881-890
Abstract
The paper presents the structure and peculiarities of the software for processing the thermodynamic information stored in the REETHERM databank. The databank stores initial data for thermodynamic calculations modeling geochemical fractionation of rare-earth elements (REE) which involves hot fluids. The software establishes relations between the following databases: BASE1 (equations of formation of REE complexes), BASE2 (indices of the HKF equation, which provides the base for the algorithm for calculating the thermodynamic indices of dissolved REE compounds), and BASE3 (references). The software is written in the Delphi Client/Server language, and the data are presented as dBase files. They allow operations with information networks, including data export-import. The thermodynamic data stored in REETHERM include indices of the HKF equation for major geochemically important types of inorganic REE complexes, as well as data on ligands and background components of natural fluids. The article contains tables and figures illustrating the effect of temperature on the stability of hydroxyl, carbonate, and bicarbonate monoligand REE complexes in the range from 25 to 350 oC. The potential of the bank for correction of stability constants with regard to changes in fluid's dielectric constant caused by the presence of significant concentrations of carbon dioxide and other nonpolar gases is illustrated by the example of carbonate complexes.
|
