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Title: Solubility behavior of quartz and corundum in supercritical water: A quantitative thermodynamic interpretation

Abstract

Dissolution reaction equilibria for {alpha}-quartz (SiO{sub 2}) and corundum ({alpha}-Al{sub 2}0{sub 3}) in pure, supercritical water are quantified using a density-dependent thermodynamic model. The database of existing solubility literature for {alpha}-quartz (0.2-10 kb, 200--575{degrees}C) is shown to be consistent with the presence of two hydrolyzed SI(IV) ion forms: Si(OH){sub 4}(aq) and Si{sub 2}O(OH){sub 6}(aq); the corundum database (1-20 kb, 400--700{degrees}C) is consistent with Al(OH){sub 3}(aq) and Al(OH){sub 4}{sup {minus}}. A third Si(IV) ion hydroxocomplex, Si{sub 2}O{sub 2}(OH){sub 5}{sup {minus}}, is indicated at lower pressures (0.03-0.10 kb). The characteristic sigmoidal nature of the solubility isobars is explained by dimerization of Si(OH){sub 4}(aq) (at high densities) or the formation of anionic hydrolysis products, Si{sub 2}0{sub 2}(OH){sub 5}{sup {minus}} and Al(OH){sub 4}{sup {minus}}, in the low density region (p < 0.01 gm/cc). By means of the evaluated equilibria, thermochemical properties of Si{sub 2}O(OH){sub 6}(aq) and Si{sub 2}O{sub 2}(OH){sub 5}{sup {minus}} are made available for the first time.

Authors:
Publication Date:
Research Org.:
Knolls Atomic Power Lab. (KAPL), Niskayuna, NY (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
69332
Report Number(s):
KAPL-4790
ON: DE95012294; TRN: 95:015473
DOE Contract Number:  
AC12-76SN00052
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: May 1995
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 15 GEOTHERMAL ENERGY; 36 MATERIALS SCIENCE; SILICON OXIDES; SOLUBILITY; CORUNDUM; QUARTZ; ALUMINIUM OXIDES; SUPERCRITICAL STATE; WATER; DISSOLUTION; THERMODYNAMICS; EQUILIBRIUM; Geothermal Legacy

Citation Formats

Ziemniak, S E. Solubility behavior of quartz and corundum in supercritical water: A quantitative thermodynamic interpretation. United States: N. p., 1995. Web. doi:10.2172/69332.
Ziemniak, S E. Solubility behavior of quartz and corundum in supercritical water: A quantitative thermodynamic interpretation. United States. https://doi.org/10.2172/69332
Ziemniak, S E. 1995. "Solubility behavior of quartz and corundum in supercritical water: A quantitative thermodynamic interpretation". United States. https://doi.org/10.2172/69332. https://www.osti.gov/servlets/purl/69332.
@article{osti_69332,
title = {Solubility behavior of quartz and corundum in supercritical water: A quantitative thermodynamic interpretation},
author = {Ziemniak, S E},
abstractNote = {Dissolution reaction equilibria for {alpha}-quartz (SiO{sub 2}) and corundum ({alpha}-Al{sub 2}0{sub 3}) in pure, supercritical water are quantified using a density-dependent thermodynamic model. The database of existing solubility literature for {alpha}-quartz (0.2-10 kb, 200--575{degrees}C) is shown to be consistent with the presence of two hydrolyzed SI(IV) ion forms: Si(OH){sub 4}(aq) and Si{sub 2}O(OH){sub 6}(aq); the corundum database (1-20 kb, 400--700{degrees}C) is consistent with Al(OH){sub 3}(aq) and Al(OH){sub 4}{sup {minus}}. A third Si(IV) ion hydroxocomplex, Si{sub 2}O{sub 2}(OH){sub 5}{sup {minus}}, is indicated at lower pressures (0.03-0.10 kb). The characteristic sigmoidal nature of the solubility isobars is explained by dimerization of Si(OH){sub 4}(aq) (at high densities) or the formation of anionic hydrolysis products, Si{sub 2}0{sub 2}(OH){sub 5}{sup {minus}} and Al(OH){sub 4}{sup {minus}}, in the low density region (p < 0.01 gm/cc). By means of the evaluated equilibria, thermochemical properties of Si{sub 2}O(OH){sub 6}(aq) and Si{sub 2}O{sub 2}(OH){sub 5}{sup {minus}} are made available for the first time.},
doi = {10.2172/69332},
url = {https://www.osti.gov/biblio/69332}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 1995},
month = {Mon May 01 00:00:00 EDT 1995}
}