Research article

Deliquescence of NaCl–NaNO₃, KNO₃–NaNO₃, and NaCl–KNO₃ salt mixtures from 90 to 120°C

Susan Carroll^*, Laura Craig and Thomas J Wolery

• * Corresponding author: Susan Carroll carroll6@llnl.gov

Author Affiliations

Energy and Environment Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550

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Geochemical Transactions 2005, 6:19 doi:10.1186/1467-4866-6-19

Published: 11 April 2005

Abstract

We conducted reversed deliquescence experiments in saturated NaCl–NaNO₃–H₂O, KNO₃–NaNO₃–H₂O, and NaCl–KNO₃–H₂O systems from 90 to 120°C as a function of relative humidity and solution composition. NaCl, NaNO₃, and KNO₃ 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. Discrepancy between model prediction and experiment 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–NO₃ and K–NO₃ ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the nonideal behavior of these highly concentrated solutions.