skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C

Abstract

We conducted reversed deliquescence experiments in saturated NaCl-NaNO{sub 3}-H{sub 2}O, KNO{sub 3}-NaNO{sub 3}-H{sub 2}O, and NaCl-KNO{sub 3}-H{sub 2}O systems from 90 to 120 C as a function of relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Discrepancy between model prediction and experimental code can be as high as 8% for relative humidity and 50% for dissolved ion concentration. The discrepancy is attributed primarily to the use of 25 C models for Cl-NO{sub 3} and K-NO{sub 3} ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the non-ideal behavior of these highly concentrated solutions.

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
936468
Report Number(s):
UCRL-JRNL-207414
TRN: US0805526
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geochemical Transactions, vol. 6, N/A, April 11, 2005, pp. 1-19; Journal Volume: 6
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BRINES; DUSTS; FORECASTING; HIGH-LEVEL RADIOACTIVE WASTES; HUMIDITY; MIXTURES; YUCCA MOUNTAIN

Citation Formats

Carroll, S A, Craig, L, and Wolery, T J. Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C. United States: N. p., 2004. Web.
Carroll, S A, Craig, L, & Wolery, T J. Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C. United States.
Carroll, S A, Craig, L, and Wolery, T J. Wed . "Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C". United States. doi:. https://www.osti.gov/servlets/purl/936468.
@article{osti_936468,
title = {Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C},
author = {Carroll, S A and Craig, L and Wolery, T J},
abstractNote = {We conducted reversed deliquescence experiments in saturated NaCl-NaNO{sub 3}-H{sub 2}O, KNO{sub 3}-NaNO{sub 3}-H{sub 2}O, and NaCl-KNO{sub 3}-H{sub 2}O systems from 90 to 120 C as a function of relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Discrepancy between model prediction and experimental code can be as high as 8% for relative humidity and 50% for dissolved ion concentration. The discrepancy is attributed primarily to the use of 25 C models for Cl-NO{sub 3} and K-NO{sub 3} ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the non-ideal behavior of these highly concentrated solutions.},
doi = {},
journal = {Geochemical Transactions, vol. 6, N/A, April 11, 2005, pp. 1-19},
number = ,
volume = 6,
place = {United States},
year = {Wed Oct 20 00:00:00 EDT 2004},
month = {Wed Oct 20 00:00:00 EDT 2004}
}
  • We conducted reversed deliquescence experiments in saturated NaCl-NaNO3-H2O and KNO{sub 3}-NaNO{sub 3}-H{sub 2}O systems at 90 C to determine relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Model predictions agree with experimental results for the NaCl-NaNO{sub 3}-H{sub 2}O system, but underestimate relative humidity by as much as 8% and solution composition by as much as 50% in the KNO{sub 3}-NaNO{sub 3}-H{sub 2}O system.
  • Boiling temperature measurements have been made at ambient pressure for saturated ternary solutions of NaCl + KNO{sub 3} + H{sub 2}O, NaNO{sub 3} + KNO{sub 3} + H{sub 2}O, and NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O over the full composition range, along with those of the single salt systems. Boiling temperatures were also measured for the four component NaCl + NaNO{sub 3} + KNO{sub 3} + H{sub 2}O and five component NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2} + H{sub 2}O mixtures, where the solute mole fraction of Ca(NO{sub 3}){sub 2}, x(Ca(NO{sub 3}){sub 2}),more » was varied between 0 and 0.25. The maximum boiling temperature found for the NaCl + KNO{sub 3} + H{sub 2}O system is {approx} 134.9 C; for the NaNO{sub 3} + KNO{sub 3} + H{sub 2}O system is {approx} 165.1 C at x(NaNO{sub 3}) {approx} 0.46 and x(KNO{sub 3}) {approx} 0.54; and for the NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O system is 164.7 {+-} 0.6 C at x(NaCl) {approx} 0.25 and x(Ca(NO{sub 3}){sub 2}) {approx} 0.75. The NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2} + H{sub 2}O system forms molten salts below their maximum boiling temperatures, and the temperatures corresponding to the cessation of boiling (dry out temperatures) of these liquid mixtures were determined. These dry out temperatures range from {approx} 300 C when x(Ca(NO{sub 3}){sub 2}) = 0 to {ge} 400 C when x(Ca(NO{sub 3}){sub 2}) = 0.20 and 0.25. Mutual deliquescence/efflorescence relative humidity (MDRH/MERH) measurements were also made for the NaNO{sub 3} + KNO{sub 3} and NaCl + NaNO{sub 3} + KNO{sub 3} salt mixture from 120 to 180 C at ambient pressure. The NaNO{sub 3} and NaCl + NaNO{sub 3} + KNO{sub 3} salt mixture has a MDRH of 26.4% at 120 C and 20.0% at 150 C. This salt mixture also absorbs water at 180 C, which is higher than expected from the boiling temperature experiments. The NaCl + NaNO{sub 3} + KNO{sub 3} salt mixture was found to have a MDRH of 25.9% at 120 C and 10.5% at 180 C. The investigated mixture compositions correspond to some of the major mineral assemblages that are predicted to control brine composition due to the deliquescence of salts formed in dust deposited on waste canisters in the proposed nuclear repository at Yucca Mountain, Nevada.« less
  • Boiling temperature measurements have been made for saturated ternary solutions of NaCl + KNO{sub 3} + H{sub 2}O and NaNO{sub 3} + KNO{sub 3} + H{sub 2}O at three selected salt ratios and for NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O over the full composition range. The maximum boiling temperature found for the NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O system is 164.7 {+-} 0.6 C, and the composition is estimated to occur at x(Ca(NO{sub 3}){sub 2}) {approx} 0.25. Experiments were also performed for the five component NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2}more » + H{sub 2}O mixtures with the molar ratio of NaCl:NaNO{sub 3}:KNO{sub 3} held essentially constant at 1:0.9780:1.1468 as the solute mole fraction of Ca(NO{sub 3}){sub 2}, x(Ca(NO{sub 3}){sub 2}), was varied between 0 and 0.25. The NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2} + H{sub 2}O system forms low melting mixtures and thus boiling temperatures for saturated were not determined. Instead, the temperatures corresponding to the cessation of boiling (i.e., dry out temperatures) of these liquid mixtures were determined. These dry out temperatures range from {approx} 300 C when x(Ca(NO{sub 3}){sub 2}) = 0 to {ge} 400 C when x(Ca(NO{sub 3}){sub 2}) = 0.20 and 0.25. The investigated mixture compositions correspond to some of the major mineral assemblages that are predicted to control the deliquescence relative humidity of salts formed by leaching dust samples from the proposed nuclear repository at Yucca Mountain, Nevada.« less
  • The influence of an oxidizing molten nitrate salt environment (60 pct NaNO/sub 3/-40 pct KNO/sub 3/) on the mechanical properties of INCOLOY Alloy 800 has been examined through a series of slow strain rate tensile tests. Fracture strain, reduction in area and ultimate tensile strength were monitored as parameters indicative of alloy susceptibility to environmental degradation. For strain rates between 2 X 10/sup -7/ sec/sup -1/ and 3.34 X 10/sup -5/ sec/sup -1/ no appreciable loss in ductility as measured by the above parameters was observed at 600/sup 0/C relative to control specimens tested in air at the same strainmore » rates and temperature. Similarly, the load-bearing capability of the alloy was unaffected by exposure to the environment. The structure of the oxide film formed by contact of the alloy with the molten salt was affected by the imposed continuous deformation. Deformation resulted in an oxide which was thicker than that formed on undeformed salt-exposed surfaces. While this difference in oxide thickness was a measurable phenomenon, the increased rate of oxidation was not great enough to alter appreciably alloy mechanical behavior in the salt compared to that measured in air over the time limits considered. In addition, fine subsurface cracks were observed in those oxides formed on deformed surfaces.« less