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http://dx.doi.org/10.7844/kirr.2022.31.3.81

Heat Balance during the Electrowinning of Neodymium Metal in Molten Salt  

Cho, Sung-Wook (Resources Utilization Division, Korea Institute of Geoscience and Mineral Resources)
Yu, Jeong-Hyun (Resources Utilization Division, Korea Institute of Geoscience and Mineral Resources)
Choi, Ho-Gil (Department of Materials Science and Engineering, Seoul National University)
Publication Information
Resources Recycling / v.31, no.3, 2022 , pp. 81-87 More about this Journal
Abstract
Energy consumption per unit weight of metal (kwh/kg of metal) is one of the most important economic indicators in the process of molten salt electrolysis. It is related to the heat loss of salt bath and the current efficiency of the process. The current efficiency is highly dependent on electrolysis temperature. On the other hand, the temperature of salt bath may increase significantly due to the difference (larger energy input than consumption) in heat balance at the beginning of electrolysis, which may cause different electrolysis temperature from an initially targeted value. This results in a bad effect on current efficiency. Therefore, it will be helpful to the reduction of energy consumption to compare the calculated and measured values of the temperature change of salt bath through the heat balance review at the early stage of electrolysis and to evaluate the energy loss to outside. In this study, based on the authors' experimental data, the heat balance was reviewed at the beginning of the electrolysis, and it was possible to evaluate the energy loss to the outside and the increase of the temperature of the salt bath quantitatively. Through such a method, heat loss reduction plan can be derived and current efficiency can be improved so that energy consumption can be reduced.
Keywords
molten salt electrolysis; neodymium; heat balance; energy consumption; electrolysis temperature; current efficiency;
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Times Cited By KSCI : 1  (Citation Analysis)
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1 S. Yan, Z. Li, B. Zhao, et al., 2005 : Status and development prospects of China's rare earth metal industry, Chinese Rare Earths, 26(2), pp.81-86.
2 X. Yin, Z. Liu and Y. Cao, 2002 : Thermal equilibrium calculation of rare earth molten salt electrolyzer, J. Baotou Univ. Iron and Steel Technology, 21(1), pp.19-22.
3 S. Pang, S. Yan, Z. Li, et al., 2011 : Advances in manufacturing technology of rare earth metals and their alloys by molten salt electrolysis in China, Chinese J. Rare Met., 35(3), pp.440-450.
4 J. Wang, C. Wang, G. Tu, et al., 2008 : Thermal equilibrium calculation of rare earth molten salt electrolyzer with 10kA bottom cathode, Chinese Rare Earths, 29(5), pp.61-63.
5 Ram A. Sharma, 1987 : Neodymium production processes, JOM, 39(2), pp.33-37.   DOI
6 T. Shimada, N. Tedzuka, Y. Shimizu, et al., 1994 : Electrochemical reduction of uranium oxide in molten fluoride mixture, JALCOM, 204, pp.1-4.
7 T. Shimada, N. Tedzuka, Y. Shimizu, et al., 1993 : Dissolution of lanthanide metals into molten lithium fluoride, Proceedings of the International Symposium on Molten Salt Chemistry and Technology, Marie-Louise Saboungi and Hirano Kojima, pp.220-230, The electrochemical society, Honolulu/Hawaii-USA, 16-21 May 1993, Printed in the USA.
8 S.-W. Cho and J.-H. Yu, 2022 : Electrowinning of neodymium metal using FLiNdBa molten salt, KJMM, 60(2), pp.124-131.   DOI
9 D. Chen, S. Yan, Z. Li, et al., 2008 : Investigation on the dissolution of neodymium metal into molten salt and the formation of sludge, Chinese J. Rare Met., 32(4), pp.482-484.
10 H. Lin, 2003 : Production and application of metallic neodymium, Powder Metallurgy Industry, 13(1), pp.34-39.
11 O. Knacke, O. Kubaschewski, K. Hesselmann, 1991 : Thermochemical properties of inorganic substances, pp.47, 170, 264, 307, 309, 1052, 1416, 1426, and 2260, 2nd Edition, Springer-Verlag Berlin, Heidelberg.
12 T. Shimada, 1996 : State of activated complex of dissolved lanthanide metals into molten lithium fluoride, JALCOM, 245, pp.142-145.
13 E.T. Turkdogan, 1980 : Selected thermodynamic functions, Physical Chemistry of High Temperature Technology, pp.5-24, Academic Press, New York.
14 C.W. Bale, E. Belisle, P. Chartrand, et al., 2016 : Factsage thermochemical software and database 2010-2016, Calphad, 55, pp.1-19.   DOI
15 R.G. Reddy and S.G. Kumar, 1994 : Solubility and thermodynamic properties of Y2O3 in LiF-YF3 melts, Metall. Mater. Trans. B, 25B, pp.91-96.