Solubility constants of hydroxyl sodalite at elevated temperatures evaluated from hydrothermal experiments: Applications to nuclear waste isolation
Abstract
In this study, solubility constants of hydroxyl sodalite (ideal formula, Na8[Al6Si6O24][OH]2·3H2O) from 25°C to 100°C are obtained by applying a high temperature Al—Si Pitzer model to evaluate solubility data on hydroxyl sodalite in high ionic strength solutions at elevated temperatures. A validation test comparing model-independent experimental data to model predictions demonstrates that the solubility values produced by the model are in excellent agreement with the experimental data. In addition, the equilibrium constants obtained in this study have a wide range of applications, including synthesis of hydroxyl sodalite, de-silication in the Bayer process for extraction of alumina, and the performance of proposed sodalite waste forms in geological repositories in various lithologies including salt formations. The thermodynamic calculations based on the equilibrium constants obtained in this work indicate that the solubility products in terms of mΣAl×mΣSi for hydroxyl sodalite are very low (e.g., ~10-13 [mol·kg-1]2 at 100°C) in brines characteristic of salt formations, implying that sodalite waste forms would perform very well in repositories located in salt formations. Finally, the information regarding the solubility behavior of hydroxyl sodalite obtained in this study provides guidance to investigate the performance of other pure end-members of sodalite such as chloride- and iodide-sodalite, which may bemore »
- Authors:
-
- Sandia National Laboratories, Carlsbad Programs Group, Carlsbad, NM (United States)
- Publication Date:
- Research Org.:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Org.:
- USDOE Office of Nuclear Energy (NE); USDOE National Nuclear Security Administration (NNSA)
- OSTI Identifier:
- 1338338
- Alternate Identifier(s):
- OSTI ID: 1396613
- Report Number(s):
- SAND2016-2300J
Journal ID: ISSN 0883-2927; 621958
- Grant/Contract Number:
- AC04-94AL85000; SAND2016-2300J
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Applied Geochemistry
- Additional Journal Information:
- Journal Volume: 74; Journal Issue: C; Journal ID: ISSN 0883-2927
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 58 GEOSCIENCES
Citation Formats
Xiong, Yongliang. Solubility constants of hydroxyl sodalite at elevated temperatures evaluated from hydrothermal experiments: Applications to nuclear waste isolation. United States: N. p., 2016.
Web. doi:10.1016/j.apgeochem.2016.09.009.
Xiong, Yongliang. Solubility constants of hydroxyl sodalite at elevated temperatures evaluated from hydrothermal experiments: Applications to nuclear waste isolation. United States. https://doi.org/10.1016/j.apgeochem.2016.09.009
Xiong, Yongliang. Sat .
"Solubility constants of hydroxyl sodalite at elevated temperatures evaluated from hydrothermal experiments: Applications to nuclear waste isolation". United States. https://doi.org/10.1016/j.apgeochem.2016.09.009. https://www.osti.gov/servlets/purl/1338338.
@article{osti_1338338,
title = {Solubility constants of hydroxyl sodalite at elevated temperatures evaluated from hydrothermal experiments: Applications to nuclear waste isolation},
author = {Xiong, Yongliang},
abstractNote = {In this study, solubility constants of hydroxyl sodalite (ideal formula, Na8[Al6Si6O24][OH]2·3H2O) from 25°C to 100°C are obtained by applying a high temperature Al—Si Pitzer model to evaluate solubility data on hydroxyl sodalite in high ionic strength solutions at elevated temperatures. A validation test comparing model-independent experimental data to model predictions demonstrates that the solubility values produced by the model are in excellent agreement with the experimental data. In addition, the equilibrium constants obtained in this study have a wide range of applications, including synthesis of hydroxyl sodalite, de-silication in the Bayer process for extraction of alumina, and the performance of proposed sodalite waste forms in geological repositories in various lithologies including salt formations. The thermodynamic calculations based on the equilibrium constants obtained in this work indicate that the solubility products in terms of mΣAl×mΣSi for hydroxyl sodalite are very low (e.g., ~10-13 [mol·kg-1]2 at 100°C) in brines characteristic of salt formations, implying that sodalite waste forms would perform very well in repositories located in salt formations. Finally, the information regarding the solubility behavior of hydroxyl sodalite obtained in this study provides guidance to investigate the performance of other pure end-members of sodalite such as chloride- and iodide-sodalite, which may be of interest for geological repositories in various media.},
doi = {10.1016/j.apgeochem.2016.09.009},
journal = {Applied Geochemistry},
number = C,
volume = 74,
place = {United States},
year = {Sat Sep 17 00:00:00 EDT 2016},
month = {Sat Sep 17 00:00:00 EDT 2016}
}
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