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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ELECTRICAL CONDUCTIVITY OF MOLTEN MIXTURES OF ZrCl4 WITH ALKALI METAL CHLORIDES
Alexander Salyulev1; Alexei Potapov2;1INSTITUTE OF HIGH TEMPERATURE ELECTROCHEMISTRY, URAL BRANCH OF RUSSIAN ACADEMY OF SCIENCE, Ekaterinburg, Russian Federation; 2INSTITUTE OF HIGH TEMPERATURE ELECTROCHEMISTRY, Ekaterinburg, Russian Federation;
Type of Paper: Regular
Id Paper: 138
Topic: 13
Abstract:
Molten salts containing ZrCl4 generally have a high vapor pressure. However, there are concentration ranges with a relatively low vapor pressure. And such melts are quite suitable for industrial use. In this work we have considered molten of MCl – ZrCl4 mixtures (where M is an alkali metal) with a relatively low saturated vapor pressure (P ⩽ 1 atm) of highly volatile ZrCl4. These mixtures can be divided into high-temperature regions with a ZrCl4 concentration of 0–30 mol. % and low-temperature regions with a ZrCl4 concentration of 50–75 mol. %.
The aim of this work is to review the available experimental data on the electrical conductivity of ZrCl4-containing salt melts with vapor pressures below atmospheric ones [1–6].
It was found that the electrical conductivity of all molten ZrCl4 - containing mixtures increases as the temperature increases, zirconium tetrachloride concentration decreases, and the molten salt-solvent is replaced in a series from CsCl to LiCl.
As the concentration of zirconium tetrachloride in melts increases, the concentration of its relatively low-mobility complex anion groups, 
(in solutions with ZrCl4 concentrations up to 33 mol.%) or 
and 
(in solutions with higher ZrCl4 concentrations) also increases. This leads to a decrease in the concentration of the main current carriers: alkaline cations and mobile Cl- ions, which are gradually replaced by bulky complex Zr(IV) groups that make a small contribution to the transfer of electricity. As a result, the electrical conductivity of molten mixtures decreases as the ZrCl4 concentration increases.
The electrical conductivity of all studied molten mixtures decreases not only with an increase in the concentration of ZrCl4, but also with a decrease in temperature as a result of a decrease in the mobility of ions (both simple and complex) and an increase in the viscosity of the melt. As a result, the electrical conductivity of high-temperature MCl - ZrCl4 melts (M is an alkali metal, with 0 - 30 mol. % ZrCl4) is in the range of 0.6 - 3.1 S/cm, is significantly higher than that of low-melting molten mixtures of the same chlorides (0.1 - 0.5 S/cm) with a high ZrCl4 content (55 - 75 mol. %).
It was found that the use of low-melting salt solvents such as the LiCl - KCl eutectic allows for a significant (by hundreds of degrees) expansion of the existence range of ZrCl4 - containing melts towards lower temperatures and saturated vapor pressures at sufficiently high electrical conductivity values (0.9 - 2.8 S/cm), which provides additional advantages for various technological processes.