2022-Sustainable Industrial Processing Summit
SIPS2022 Volume 4 Kipouros Intl. Symp. Molten Salt, Ionic & Glass-forming Liquids & Powdered Materials
| Editors: | F. Kongoli, R. Fehrmann, V. Papangelakis, I.Paspaliaris, G. Saevarsdottir. |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2022 |
| Pages: | 100 pages |
| ISBN: | 978-1-989820-40-7(CD) |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Continuous monitoring and control of the AlF3 content of the cryolitic melt in aluminium electrolysis
Vicky Vassiliadou1; Antonis Peppas2; Maria Taxiarchou3; Ioannis Paspaliaris3;1MYTILINEOS HOLDINGS S.A, Agios Nikolaos, Greece; 2NATIONAL TECHNICAL UNIVERSITY OF ATHENS, Zografos Campus, Greece; 3NATIONAL TECHNICAL UNIVERSITY OF ATHENS, Athens, Greece;
Type of Paper: Regular
Id Paper: 378
Topic: 13
Abstract:
The aim of this paper is to summarize the mathematical equations applied to the modelling of the physicochemical properties of the aluminium electrolysis cryolite melts and the study of the effect on the properties of its aluminium fluoride content and the development of a methodology for the direct determination of its concentration in the electrolysis bath that can be applied in industrial scale electrolysis cells.
The AlF3 content of the electrolyte melt is one of the most important parameters affecting the physicochemical properties of the electrolysis bath. In the current industrial practice, the determination of AlF3 concentration in the bath is performed through periodic sampling, chemical analysis of the selected samples and, based on the chemical analysis results, the appropriate quantity of AlF3 addition is determined. This procedure is time consuming, and its major disadvantage is that between the time of sampling and analysis until the addition of the corrective AlF3 quantity, the AlF3 content of the bath has changed. This creates a serious problem in the proper control of the AlF3 concentration in the electrolysis bath and the stable operation of the electrolysis cell.
A methodology for the real time determination of the AlF3 content of the electrolysis bath has been developed based on the measurement of the bath resistance. According to the proposed methodology, a given change in the anode cathode distance is applied and the corresponding change in the bath resistance is measured and, from its value, the bath electrical resistivity is determined. The value of the electrical resistivity is correlated to the value of the theoretical electrical resistivity of the bath and through an appropriate algorithm the AlF3 content of the bath is determined in real time with sufficient accuracy.
Keywords:
Electrolysis; Moltensalt; Technology;References:
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