Abstract
Data on the density and electrical conductivity of salt melts are of interest for both the assessment of the possibility of their application for the electrolytic production and refining of beryllium and other manufacturing processes and an analysis of the possible interaction of their constituents. Data on the density of molten salt systems comprising beryllium fluoride and alkali-metal chlorides are obtained by hydrostatic weighing. A ball float and a suspension filament are made of platinum. As the crucible and thermocouple case material, beryllium oxide is used. For the BeF2–MCl (M = Li, Na, K, and Cs) and BeF2–(Li–K)eut–Cl systems, 9 to 14 molten salt mixtures containing from 0 to 100% beryllium fluoride are studied when the temperature increases by 100–200 K above the melting temperature of a mixture at an average step of 10 K. Because of the peculiarities of the behavior of individual beryllium fluoride upon heating above the melting temperature (high viscosity and active evaporation), the density of a molten salt is measured by the maximum bubble pressure method. Along with the density, the electrical conductivity of the melts is measured by the capillary method. The measuring cell material is beryllium oxide; as the measuring electrodes, platinum rods 1 mm in diameter are used. The cell constant is determined and regularly controlled using a high-purity potassium chloride melt. All procedures related to the preparation of salt mixtures, their sampling for chemical analysis, and measuring the properties are performed in an isolated dry and additionally purified argon atmosphere. The measurement results are presented in the form of first- and second-order polynomials, which indicate the temperature dependences of density and electrical conductivity for different salt mixture compositions. The values of the simultaneously measured density and electrical conductivity are used to calculate the molar volume and the molar electrical conductivity of the electrolytes. Molar volume isotherms exhibit almost linear behavior, which indicates a weak interaction between the melt constituents. The molar conductivity isotherms are characterized by a typical inflection point, which corresponds to compositions with ~30 mol % beryllium fluoride, which can be related to the formation of complex compounds in the liquid phase.
REFERENCES
Yu. K. Delimarskii and O. G. Zarubitskii, Electrolytic Refining of Heavy Metals in Ionic Melts (Metallurgiya, Moscow, 1975).
V. I. Shchegolev and O. A. Lebedev, Electrolytic Production of Magnesium (Ruda i Metally, Moscow, 2002).
P. A. Petrov and Yu. V. Sharikov, “Mathematical simulation of control subsystem of an aluminum electrolyzer with roasted anodes,” Tsvetn. Met. 10, 81–84 (2006).
P. Arkhipov and O. Tkacheva, “The electrical conductivity of molten oxide-fluoride cryolite mixtures,” Mater. 14, 7419 (2021).
A. N. Efremov, N. P. Kulik, A. A. Kataev, A. P. Apisarov, A. A. Red’kin, A. Yu. Chuikin, P. A. Arhipov, and Yu. P. Zaikov, “Electrical conductivity, density, and liquidus temperature of equimolar KCl–PbCl2 mixture with lead oxide additions,” Izv. Vyssh. Uchebn. Zaved., Tsvetn. Metall., No. 5, 10–16 (2016).
L. E. Ivanovskii, V. A. Khokhlov, and G. F. Kazantsev, Physical Chemistry and Electrochemistry of Chlorine–Aluminate Melts (Nauka, Moscow, 1993).
V. I. Minchenko and V. P. Stepanov, Ionic Melts: Elastic and Caloric Properties (IVTE UrO RAN, Yekaterinburg, 2008).
S. F. Katyshev and V. N. Desyatnik, “Density and surface tension of the NaF–NaCl–ZrF4 melts,” At. Energ. 84 (1), 61–64 (1998).
S. F. Katyshev, N. V. Shirokova, and L. M. Teslyuk, “Electrical conductivity of LiCl–KF–ZrF4 molten mixtures,” Elektrokhim. 53 (5), 618–621 (2017).
M. V. Smirnov, V. P. Stepanov, and V. A. Khokhlov, “Ionic structure and physico-chemical properties of halide melts,” Rasplavy, No. 1, 64–73 (1987).
N. V. Shirokova, “Physicochemical properties of molten mixtures of zirconium fluoride with alkaline metals halides,” Extended Abstract of Cand. Sci. (Chem.) Dissertation, Yekaterinburg, 2010.
V. N. Desyatnik, S. F. Katyshev, and S. P. Raspopin, “Physicochemical properties of melts of uranium tetrachloride with alkali metal chlorides,” At. Energ. 42 (2), 99–103 (1977).
A. A. Klimenkov, N. N. Kurbatov, S. P. Raspopin, and Yu. F. Chervinskii, “Density of molten mixtures of beryllium fluoride with alkali metal fluorides,” in Proceedings of the III Ural Scientific Seminar on Chemical Reactions and Processes in Molten Electrolytes (Perm’, 1982), pp. 112–113.
O. I. Rebrin, A. E. Mordovin, and I. F. Nichkov, “BeCl2–LiCl system,” Zh. Inorg. Khim. 30 (10), 2663–2665 (1985).
O. I. Rebrin, I. F. Nichkov, and A. E. Mordovin, “Density and electrical conductivity of molten salt mixtures of beryllium and sodium chlorides,” Zh. Fiz. Khim. LVII (3), 725–728 (1983).
O. I. Rebrin, A. E. Mordovin, and I. F. Nichkov, “The BeCl2–CsCl system,” Zh. Neorg. Khim. 31 (6), 1519–1521 (1986).
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Translated by N. Kolchugina
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Krylosov, A.V., Polovov, I.B. & Rebrin, O.I. Density and Electrical Conductivity of Molten Beryllium Fluoride–Alkali-Metal Chloride Salt Mixtures. Russ. Metall. 2023, 229–234 (2023). https://doi.org/10.1134/S003602952302012X
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DOI: https://doi.org/10.1134/S003602952302012X