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

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. © 2005 American Institute of Physics. @DOI: 10.1063/1.1872292#