GB930831A - Improvements in or relating to electrolytic cells for the production of aluminium - Google Patents

Abstract

930,831. Electrolytic apparatus. BRITISH ALUMINIUM CO. Ltd. June 22, 1959 [June 24, 1958], No. 21367/59. Drawings to Specification. Class 41. An electrolytic cell for the production of aluminium comprises refractory side and end walls and a floor of refractory material defining a chamber adapted to contain a pool of molten aluminium in the lower part thereof and a body of molten electrolyte above and in contact with the pool of molten aluminium, the side walls being longer than the end walls, at least one anode member disposed at least partially within the chamber and adapted to be in contact with the molten electrolyte and a plurality of cathodic current-conducting elements arranged in a row connected to a common cathode bus-bar and extending across the shortest horizontal dimension of the cell, one extremity of each cathodic current-conducting element extending into said lower part of the chamber to contact the pool of molten aluminium, at least the surface of said extremity adapted to contact the molten aluminium consisting essentially of a refractory hard metal. The expression " refractory hard metal " is defined as a material possessing a low electrical resistivity, a low solubility in molten aluminium and molten electrolyte under cell operating conditions, good stability under conditions existing at the cathode of a reduction cell, and which is wettable by molten aluminium under cell operating conditions. Preferred refractory hard metals are the carbides and borides of titanium, zirconium, tantalum and niobium, and mixtures thereof. The cells may be constructed with a metal shell, e.g. steel within which is an insulating lining such as alumina, bauxite, clay or aluminium silicate bricks and within that lining may be the refractory lining of for instance carbon, alumina, fused alumina, silicon carbide or silicon nitritebonded silicon carbide. The subject-matter of Specification 930,832 is disclaimed. Specification 917,350 also is referred to. Reference has been directed by the Comptroller to Specification 802,905.