Siberian Federal University, Krasnoyarsk, Russia:

S. G. Shakhray, Assistant Professor (Chair of Technosphere Safety of Mining and Metallurgical Production), e-mail: shahrai56@mail.ru
P. V. Polyakov, Professor-Consultant (Chair of Non-Ferrous Metals Metallurgy)

Scientific-Technical Center “Elter”, Krasnoyarsk, Russia:
A. M. Ivanova, Chief Executive Officer

LLC “RUSAL Engineering-Technical Center”, Krasnoyarsk, Russia:
E. R. Shaydulin, Manager

Anode cover is an important part of a dissipative system - a cell with prebaked anodes. Cover reduces the rate of anode oxidation by atmospheric air and stabilizes cell’s heat balance of bath, maintains the target level of the electrolyte, provides optimal ledge shape, adsorbs volatile fluorides, protects anode holder nipples from melt influence during an anode effect, extends the cell’s life, prevents excessive heat loss, reaching 153 kW, and electrical energy cost of its compensation. Hence, anode cover has a significant impact on the technical, economic and environmental performance of electrolysis. It reduces carbon materials, energy consumption and the pollutant emissions volume. The cover quality depends on raw materials characteristics, processing and mixing technologies, transportation and storage methods, algorithm of cover material loading into cell, and its operational properties, including chemical and granulometric composition, gas permeability, thermal conductivity, resistance to degradation, thickness of the layer. The research results of physical properties of aluminum cell cover material are presented in the paper. The particle size distribution and temperature impacts on the cover material properties are found. Research methods are presented. Cover materials compositions providing anode protection from oxidation, increasing or reduction of heat dissipation from anode massive that allows controlling anode-cathode distance and eliminating the cell’s MHD instability are offered. Recommendations for improving the covering material composition which provide its consumer properties increasing are developed.

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9. Blasques J. E. M., Guilherme E. da Mota, Giancarlo De Gregoriis. The importance of cover stability and cover practice on cell stability and performance. Proceedings of the 9^th Australasian Aluminium Smelting Technology Conference and Workshop. Terrigal, New South Wales, 2007. p.
10. Taylor M. P., Johnson G. L., Andrews E. W., Welch B. J. The Impact of Anode Cover Control and Anode Assembly Design on Reduction Cell Performance. Light Metals. Charlotte, North Carolina : TMS, 2004. pp. 199–206.
11. Andrews E. W., Taylor M. P., Johnson G. L., Coad I. The Impact of Anode Cover Control and Anode Assembly Design on Reduction Cell Performance. Part 2. Light Metals. San Francisco, California : TMS, 2005. pp. 357–363.
12. Perruchoud R. C., Meier M. W., Fischer W. K., Schmidt-Hatting W. H. P. Anode properties, cover materials and cell operation. Light Metals. Warrendale, Pennsylvania : TMS, 2001. pp. 695–700.
13. Halldor Gudmundsson. Improving anode cover material quality at Nordural — quality tools and measures. Light Metals. San Francisco, California : TMS, 2009. pp. 467–472.
14. Woodfield D., Picot G., Harding M. Toward optimum anode cover. Proceedings of the 8^th Australasian Aluminium Smelting Technology Conference and Workshop, Yeppon, Australia, 2004. p. 16.