2017-Sustainable Industrial Processing Summit
SIPS 2017 Volume 3. Gaune-Escard Intl. Symp. / Molten Salt and Ionic Liquid
| Editors: | Kongoli F, Fehrmann R, Gadzuric S, Gong W, Seddon KR, Malyshev V, Iwata S |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2017 |
| Pages: | 151 pages |
| ISBN: | 978-1-987820-65-2 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
CD shopping page
Maximum on Molten TeCl4 Electrical Conductivity Polytherm
Alexander Salyulev1; Alexei Potapov1;1INSTITUTE OF HIGH TEMPERATURE ELECTROCHEMISTRY, Ekaterinburg, Russian Federation;
Type of Paper: Regular
Id Paper: 44
Topic: 13
Abstract:
It is assumed that electrical conductivity polytherms of molten salts should pass through a maximum if the measurements were carried out up to sufficiently high temperatures. However, due to the experimental difficulties, the maxima were found only in a limited number of molten salts. The high vapor pressures over the salts (tens atmospheres) at high temperatures are the main obstacle at measurements.
In this work, we constructed a quartz cell of capillary type, specifically designed to measure electrical conductivity at high temperatures and pressures. Using the cell we measured the electrical conductivity of molten TeCl4 through a temperature range from 536 K to 761 K, i.e. 106 degrees above the normal boiling point of the salt and 93 degrees above the maximum temperature reported in previous studies.
The experimental points were approximated by the following equation:
κ = 1.5946�10-2 - 2.1901�10-3T + 7.5740�10-6T2 - 5.6833�10-9T3, S/cm
For the first time the maximum on the conductivity polytherm of molten TeCl4 was experimentally found. κmax = 0.245 S/cm. Both at heating and at cooling, the maximum was recorded at 705 K.
The activation energy of electrical conductivity of molten TeCl4 decreases from 20.5 kJ/mol at 536 K to zero near 705 K and then to -7.5 kJ/mol at 761 K.
The reasons for the appearance of maxima on the conductivity polytherms of molten tellurium tetrachloride are discussed. In general, the appearance of conductivity maxima probably is connected to the different temperature dependence of ions mobility, density and ionization degree of the salt molecules.