Arrangement of current supply to furnaces for production of aluminium by melt electrolysis

摘要

In an electrolytic aluminium furnace having a continuous self-baking anode and a molten aluminium pool cathode on the furnace bottom connection is made to the cathode pool by contact rods which pass through the anode into the molten aluminium, the rods being insulated from the anode and the electrolyte. As shown, a cathode rode 4 of material resistant to liquid aluminium, such as a boride or carbide of titanium or zirconium, provided with an insulating sleeve 7 of nitride-bonded silicon carbide is located by a distance piece 8 of non-conductive refractory material from a tube 5 of aluminium which is adhered to the baked zone of the anode and is progressively extended at its upper end as its lower end is melted on lowering of the anode. The space between the tube and the rod may be used to exhaust furnace gas or to supply alumina. Instead of the insulating sleeve between the tube and rod the space may be packed with granular alumina or the alumina may be mixed with fluorides when the furnace heat effects sintering. A row of cathode contact rods may be disposed between two rows of iron anode supporting and contacting rods, which may be coated with titanium carbide, to form a quincunx array, or the tubes 5 may themselves be of the carbidecoated iron and serve as anode supporting connections. In either case the anode connections have conical ends or are screwed into the baked part of the anode so that they may be raised as the anode is consumed, and the electrode connections are connected to parallel alternate anode and cathode bus-bars. Instead of providing a separate tube for each cathode connection several may be disposed within one tube or channel, e.g. as in the embodiment of Fig. 3 (not shown) in which aluminium sheets drawn from rolls are passed downwardly through the anode and located in position to form a rectangular section channel by fixed shaping and reinforcing members supported from above the anode.