GB852899A - Improvements in or relating to multi-cell electrolytic furnaces - Google Patents

Abstract

852,899. Fused - electrolyte apparatus. MONTECATINI SOC. GENERALE PER L'INDUSTRIE MINERARIA E CHIMICA, and DE VARDA, G. Dec. 31, 1957 [Jan. 5, 1957], No. 40487/57. Class 41 Ina a process for producing metals, e.g. aluminium, from a fused salt bath by electrolysis in a furnace having plane, parallel, inclined electrodes 9, e.g. of graphite, including consumable anodes, the anodes are restored by sliding members 27, e.g. of prebaked electrodic carbon or cokified Soderberg paste, from the top along a plane 29 inclined at an acute angle to the plane of the consumable face of the anode exposed to the bath. The plane 29 and the plane of the consumable face may be on opposite sides of the vertical as shown, or on the same side, Fig. 1, not shown, and the members 27 may comprise separate superposed blocks of prebaked carbon, with pitch, tar or Soderberg paste between. The plane 29 defines a narrow space filled with liquid of the bath, and channels 30 in the electrodes lead aluminium from the cathode face to the space 29. Inert, thermally insulating material 13, 15 supports and insulates the electrodes 9, except for their active faces, and forms chambers 12 for aluminium collection, and blocks 19 of the same material overlie the electrodes 9, channels 17 being provided for electrolyte flaw. Gas chambers 20 are separated from interelectrode spaces 14 by porous slabs of magnesia or asbestos, not shown, which may be apertured, and heat insulating layer 24, coated at 28 with an inert material, overlies the blocks 19. The material 28 may be electro-fused magnesite sintered or treated as described in Specification 847,970, or may be a silicon nitride or bonded silicon carbide refractory. The chambers 20 are closed by a heat insulating cover 22 having three apertures for each cell 14 each closed at 23, each aperture leading to an inclined conduit 26 of refractory material for ingress of restorable anode material 27. Where the material 27 is fused Soderberg paste, the conduit 26 may be lined with metal sheets. Material 27 is supplied periodically through the cover 22. Specifications 800,092,. 802,959 and 814,754 also are referred to.