2025 - Sustainable Industrial Processing Summit
SIPS2025 Volume 11. Intl. Symp on Iron and Steel, Non-ferrous, Metals, Bioextraction, Molten and Recycling
| Editors: | F. Kongoli, P. Assis, R. Alvarenga, J.A. de Castro, B. Deo, W.F. Santos Jr., S.L. de Andrade, GS. Mahobia, T. Usui, J. Antrekowitsch, A. Charitos, C. Oosterhof, M. Stelter, Z. Wang, A. Dmitriev, M.C. Gomez Marroquin, Y. Gordon, M. Naimanbayev, S. Prakash, V. Tsepelev |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2025 |
| Pages: | 298 pages |
| ISBN: | 978-1-998384-58-7 (CD) |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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MOLAR ELECTRICAL CONDUCTIVITY OF MOLTEN (LiCl-KCl)eut. - PbCl2 MIXTURES
Alexei Potapov1; Alexander Salyulev2;1INSTITUTE OF HIGH TEMPERATURE ELECTROCHEMISTRY, Ekaterinburg, Russian Federation; 2INSTITUTE OF HIGH TEMPERATURE ELECTROCHEMISTRY, URAL BRANCH OF RUSSIAN ACADEMY OF SCIENCE, Ekaterinburg, Russian Federation;
Type of Paper: Regular
Id Paper: 134
Topic: 13
Abstract:
The (LiCl-KCl)eut.- PbCl2 melts can be used as a reaction medium for “soft chlorination” during pyrochemical reprocessing of spent nuclear fuel, as well as for electrolytic extraction and refining of metallic lead and its alloys.
Previously, we measured the specific electrical conductivity of molten (LiCl-KCl)eut.- PbCl2 mixtures in the entire concentration range and in the temperature range from the liquidus to 994 K. In this work we calculated the density and molar volumes of the quasi-ternary (LiCl−KCl)eut. − PbCl2 system in the entire range of PbCl2 concentrations. This system may be used in a vast number of technological operations. The calculation was performed by an original method using experimental data [1]. Based on the obtained results, the molar electrical conductivity and its activation energy were also calculated.
It was found that the specific electrical conductivity of molten (LiCl-KCl)eut. – PbCl2 mixtures decreases with the addition of PbCl2, while the molar electrical conductivity, on the contrary, increases. The molar electrical conductivity (Λ) of molten PbCl2 is higher than the electrical conductivity of the LiCl-KCl eutectic by approximately 30%. For all molten mixtures, the ln Λ vs. 1/T dependence is not linear. For example, at 773 K, the molar conductivity has positive deviations from additive values (~ +1.6%). However, with increasing temperature, the deviations decrease, become negative and further increase in the negative direction with the increasing temperature (-5.3 % at 973K). This indicates different predominant mechanisms of electrical transport at different temperatures.
In general, the isotherms of molar conductivity in the (LiCl-KCl)eut. - PbCl2 system are close to linear. This indicates weak interaction in the system. The data on electrical conductivity and molar volumes of the (3LiCl-2KCl) - PbCl2 melts are compared with those earlier obtained in our studies on the (3LiCl-2KCl) - CdCl2 [2] and (3LiCl-2KCl) - SrCl2 molten mixtures [3].
When adding PbCl2, the activation energy of molar electrical conductivity decreases until the PbCl2 concentration of 30-40% is reached and then increases. The available data on the structure of the melts [4] indicate that, along with simple ions, complex chloride anion groups of various compositions are present. These groups were also considered for the analysis of the results. A relatively complex behavior of deviations of molar electrical conductivity depending on the temperature, activation energy and the PbCl2 concentration is associated with the presence of two complex-forming ions with almost equal ionic potentials (Li+ and Pb2+) in the system.
According to the obtained electrical conductivity data, the liquidus line of this system has been built. It is in good agreement with the literature data.