Physicochemical modeling as applied to study of sulfoarsenide complexes in hydrothermal solutions
N.V. Vilor a , L.A. Kaz'minb
a Institute of Geochemistry, Siberian Branch of the RAS, 1a ul. Favorskogo, Irkutsk, 664033, Russia
b Research Geotechnological Center, Far Eastern Branch of the RAS, 30 Severo-Vostochnoe shosse, Petropavlovsk-Kamchatsky, 683002, Russia
Keywords: Thermodynamic constants; solubility; orpiment; inverse problem; arsenic; sulfoarsenides
Pages: 457-467
Abstract
System As-Na-S-Cl-H-O was studied. The research was carried out in three stages: (1) selection of the most likely complexes resulting from arsenic sulfide dissolution, (2) calculation of their thermodynamic constants, and (3) comparison of calculated data with thermodynamic database obtained in tests with the solution of inverse thermodynamic problems using the Selektor program complex. The system As-Na-S-Cl-H-O included more than 230 dependent components, which were divided into two groups, base and functional. The former group includes components of the solution (NaCl, NaOH, Na2S, NaHS, HCl, H2S, H2SO4, sulfates, H2SO3, sulfites, thiosulfates, Na+, Cl-, HS-, S2-), gas phase (43 components), and solid phase (orpiment, red arsenic, arsenolite, claudetite, arsenic, sulfur, sodium salts). Thermodynamic constants of the base components are contained in the Selektor database (they were borrowed from reference-books). The latter group includes 77 complexes labile in the solution but determining the solubility of arsenic and stability of its solid phases. Physicochemical modeling was performed in H2S (≤0.01 m, pH = 1-10), Na2S, and NaHS solutions at 25-250
|
