National University of Science and Technology “MISiS”, Moscow, Russia

A. P. Lysenko, Associate Professor of the Department of Non-Ferrous Metals and Gold, e-mail: reikis@yandex.ru
S. Yu. Shilovskiy, Researcher of the Department of Non-Ferrous Metals and Gold
E. S. Kondrateva, Post-Graduate Student of the Department of Non-Ferrous Metals and Gold

The possibility of obtaining ligatures from aluminum, copper and zinc oxides in aluminum electrolyzers is considered. This solution allows to combine two processes in one device: electrochemical and thermal. Thermodynamic analysis showed that almost all alloying additives can be reduced from oxides by thermal method, and alumina and alkaline earth metals — by electrochemical method. The ligature additive can be introduced into Soderberg’s electrolyzers with self-igniting anodes not only through the electrolyte, but also through the anode mass. Previously, it was thought that the reason for the low current anode yield is the interaction of the carbon anode with oxygen to form CO₂ and CO. Our experiments have confirmed that the anode material and structure are not responsible for additional carbon losses of the anode gas. The chemical activity of the binder is higher than that of the coke filler and therefore the binder burns out faster than the filler. Particles of coke-filler are separated from the anode and form a “coal foam”, which violates the technological process of electrolysis. We have made a number of experiments to identify the inhibitory capabilities of copper and zinc oxides on the structure of self-igniting anodes. Copper or zinc inhibitors block the active centers of the binder. The inhibitor, adsorbed on the surface of the coal, makes its potential more positive, thereby slowing down the oxidation process. As a result, there is inhibition of the activity of the binder and the alignment of the anode sole. The proposed technical solution allows to reduce the consumption of anode mass, improve the quality of the anode by reducing the reactivity the CO₂current and improve the technical and economic performance of the aluminum production technology. Offered several options for the supply of the alloying elements in the Soderberg’s electrolyzers and in electrolytic cells with baked anodes, equipped with automatic alumina point feeders. As a result of laboratory studies, aluminum alloys Al – Cu, Al – Zn containing 4.3% copper and 4.9% zinc were obtained.

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