GB881452A - Quick starting of closed multi-cell furnace for electrolytic aluminium production - Google Patents

Abstract

881,452. Fused electrolyte apparatus. MONTECATINI SOC. GENERALE PER L'INDUSTRIA MINERARIA E CHIMICA, and DE VARDA, G. Jan. 27, 1958 [Jan. 31, 1957], No. 2612/58. Class 41. [Also in Group XI] A method of operating a multi-cell furnace for producing aluminium by electrolysis comprises heating the cells while they are empty to about 700‹ C. by electric resistances located in channels 18, 33, 35 in the bottom and side walls of each cell, introducing enough molten aluminium into each cell via the channels 35, those resistors having been removed, to short circuit adjacent electrodes, and passing an electrolysis current to raise the temperature to about 950‹ C. and introducing fused bath into the cells and increasing the applied electrolysis voltage, the resistances being disconnected. Each electrode comprises superposed graphite members 23, 24, 2, 3 located by co-operating recesses 25 and projections 26 and a restoring anode layer 1. The electrode parts are located laterally by projections engaging grooves 12 in dividing walls 13 and in the refractory lining 39 of side walls 31, Fig. 2. The furnace is of the necklace type, e.g. as described in Specification 814,754 in which the fused bath passes by gravity through the cells, via channels 10, a suitable device being provided to raise the bath to its starting point, e.g. as described in Specifications 846,305 and 846,331. Internal cell surfaces, apart from electrodes, are lined with magnesium oxide, e.g. at 22, which may be treated, e.g. as described in Specification 847,970 to render it impermeable to the bath. All the electric resistances are removable. Suitable means for introducing the bath are provided at one end of the necklace. The pockets 35 which are in a wall 44 dividing two parallel rows of cells, are topping pockets connected by conduits 17 with each cell. Specifications 852,899 and 881,453 also are referred to.