Reference Correlations for the Viscosity of 13 Inorganic Molten Salts

Abstract

In 1988, reference correlations for the viscosity of a selection of molten inorganic salts were proposed by Janz and have been used extensively. During the last 31 years, many additional measurements have been published. In a very recent paper, new reference correlations for the thermal conductivity of 13 inorganic molten salts were proposed. In this paper, reference correlations for the viscosity of those same salts are proposed. All available experimental data for the viscosity of 13 inorganic molten salts have been critically examined with the intention of establishing improved or new reference viscosity correlations. All experimental data have been categorized into primary and secondary data according to the quality of measurement specified by a series of criteria. Standard reference correlations are proposed for the following molten salts (with estimated uncertainties at the 95% confidence level given in parentheses): LiNO3 (6.7%), NaNO3 (3.0%), KNO3 (3.0%), NaBr (1.6%), KBr (2.0%), RbBr (2.2%), LiCl (3.7%), NaCl (2.4%), KCl (1.6%), RbCl (3.6%), CsCl (1.1%), NaI (1.5%), and RbI (1.5%).

On the Use of the Angell–Walden Equation To Determine the “Ionicity” of Molten Salts and Ionic Liquids

“…Walden Plots for Molten Salts. Table 1 lists the data sources for the conductivity and viscosity of the high-and moderate-temperature molten salts examined, 57−78 including the recent critically examined reference correlations for the viscosity of some halides made by Tasidou et al 79 The Walden plots of the six "basic" alkali metal (Li, Na, and K) fluorides and chlorides (except KCl) that are known to have free halide ions with no cation−anion association 97 lie all or in part well above the aqueous KCl reference line and therefore should be classified as superionic by Angell's scheme. However, these salts "can be depicted by a simple picture of charged hard spheres and are thus easily described by an alternation of cationic and anionic shells around a central ion" 98 and have low, and very similar, NE deviation parameters (Table 2).…”

“…Table lists the data sources for the conductivity and viscosity of the high- and moderate-temperature molten salts examined, − including the recent critically examined reference correlations for the viscosity of some halides made by Tasidou et al (The Supporting Information lists the values employed.) Data sources for an intermediate-temperature molten salt (tetrabutylammonium tetrabutylborate, [NBu 4 ]­[BBu 4 ]); − the eutectic mixed nitrate Rb 3 Na 2 (NO 3 ) 5 ; − and three room-temperature ionic liquids, the aprotic 1-butyl-3-methylimidazolium bis­(trifluoromethylsulfonyl)­imide ([BMIM]­[Tf 2 N]) − and the protic salts 1-methyl-2-oxopyrrolidinium tetrafluoroborate ([PyrOMe]­[BF 4 ]) and 1,8-diazabicyclo-[5,4,0]-undec-7-eneium methanesulfonate ([DBUH]­[CH 3 SO 3 ]), are also listed.…”

Determination of Kinetic Properties of Ni(II) Ions in Molten LiF-NaF-KF via Voltammetry

“…Most diffusivity values for Ni(II), Fe(II), and Cr(II, III) in FLiNaK fall under 1 × 10 -5 cm 2 s −1 , indicating that diffusivities of transition metals in FLiNaK appear to be approximately an order of magnitude lower than in chloride-based salts. There are several related factors which correlate with low diffusivity of transition metal cations in FLiNaK compared to chloride-based molten salts, including (1) higher viscosity of FLiNaK (4.04 cP at 873 K) 13 than chloride-based molten salts such as LiCl (1.51 cP at 879 K) and eutectic LiCl-KCl (1.46 cP at 875 K), 29 (2) lower electrical conductivity in FLiNaK (1.26 S cm -1 at 773 K) 30 than in chloride-based salts such as eutectic LiCl-KCl (1.87 S cm -1 at 773 K), 31 and (3) the complexation and speciation of transition metals in molten salts. A combination of these related properties explains the measured low diffusivity of Ni (II) in FLiNaK, e.g., D Ni(II) = 1.05 × 10 -6 cm 2 s -1 at 798 K, in comparison to chloride-based molten salts, e.g., D Ni(II) = 1.69 × 10 -5 cm 2 s -1 at 790 K in LiCl-KCl.…”

Saline: An API for Thermophysical Properties

“…Janz et al prepared several reports on the existing thermophysical property data over the years [18]- [23]. Serrano-Lopez et al, Tasidou et al, and Magnusson et al have compiled the most recent data [11], [16], [24]. These data sets and reports have been useful for finding the original data for further details such as measurement technique and error margins.…”