Reference Correlations for the Density and Viscosity of Molten Alkali and Alkaline Earth Fluoride Salts

Journal Article · Wed May 07 00:00:00 EDT 2025 · Journal of Physical and Chemical Reference Data

DOI:https://doi.org/10.1063/5.0264576· OSTI ID:3002723

Birri, A. ^[1]; Chesser, Ryan ^[1]; Termini, Nick ^[1]; Numbers, Jacob C. ^[2]; Garland, Kevin ^[3]; Rose, Melissa A. ^[4]

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1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
2. Brigham Young Univ., Provo, UT (United States)
3. Michigan Technological Univ., Houghton, MI (United States)
4. Argonne National Laboratory (ANL), Argonne, IL (United States)

While there is a significant body of literature pertaining to thermophysical property measurements of molten salts, there is often a wide degree of variability among independent measurements of the same compounds. As such, the scientific community benefits greatly from an unbiased, independent assessment of duplicate datasets, so that reference correlations which describe these thermophysical properties as functions of temperature can be determined and then commonly used by researchers, scientists, and engineers. With regard to molten fluoride compounds, a significant time has elapsed since density and viscosity reference correlations have been determined; Janz conducted the most recent effort, in 1988, to provide reference correlations for the densities and viscosities of molten fluoride compounds via the National Standard Reference Data System coordinated by the National Bureau of Standards. Since then, new data have been published for molten fluoride compounds, and a new precedent has surfaced for putting forth reference correlations that involve fitting to multiple primary datasets. In this work, reference correlations are put forth for molten alkali and alkaline earth fluoride compounds in an effort to provide updated, improved correlations for general use. For molten alkali fluoride densities, estimated uncertainties with a 95% confidence interval are summarized as follows: LiF (0.63%), NaF (0.48%), KF (0.76%), RbF (0.93%), and CsF (0.75%). For molten alkaline earth fluoride densities, an estimated uncertainty was not able to be quantified for BeF₂ because of limited data; however, estimated uncertainties with a 95% confidence interval are summarized as follows for the remaining alkaline earth fluorides: MgF₂ (1.5%), CaF₂ (0.92%), SrF₂ (1.6%), and BaF₂ (0.23%). For molten alkali fluoride viscosities, uncertainty was not able to be quantified for RbF and CsF because of limited data; however, estimated uncertainties with a 95% confidence interval are summarized as follows for the remaining alkali fluorides: LiF (4.4%), NaF (3.0%), and KF (4.0%). For molten alkaline earth fluoride viscosities, limited consistent data resulted in the recommendation of single datasets (from literature) that are deemed to be the most trustworthy based on the quality of the underlying experimental studies.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 3002723
• Journal Information: Journal of Physical and Chemical Reference Data, Journal Name: Journal of Physical and Chemical Reference Data Journal Issue: 2 Vol. 54; ISSN 0047-2689; ISSN 1529-7845
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English