Improvements in or relating to self-baking anodes for electric furnaces

摘要

767,147. Electric furnaces with self-baking electrodes. KAISER CO., H. J. July 19, 1954 [July 20, 1953], No. 21033/54. Class 39(3) A self-baking anode in an electric furnace for melting ferro-alloys, producing calcium carbide or the electrolytic production of alumnium has a central hollow part forming a chamber 40 lying wholly below the unbaked surface of the anode, and furnace gases-including fluorine and carbon monoxide are withdrawn from the furnace through this chamber. The lower edge of the chamber 40 extending to just above the molten charge. The tar vapours at the top surface of the anode may be led away with the other furnace vapours and are burnt. In Fig. 1 in which inclined contact pins 29 supply current to the electrode in an anode casing 25, a hollow vane with side walls 45 open at the bottom 42 and converging at the top to form a thin upper edge 47 dividing the electrode mass is inserted in the anode mass parallel with the transverse sides of the anode casing 25 and extends wholly across the electrode. The walls 45 are connected by a rib 41 which rises as shown in Fig. 2 from a central low point to the sides of the electrode and guides the rising furnace gases through apertures 43 in the vane 45 into gas outlet pipes 44 in which the gases are burnt at 49 and detoxicated in pipes 50. The anode casing 25 is closed at the top by hinged flaps 27, and tar vapours from the top surface of the anode pass through apertures 48 into the outlet pipes 44. The inner ends of the inclined contact pins are nearer to the. walls 45 of the vane than to the electrode casing 25, whereby the lower electrode surface slopes upwardly towards the gas collection chamber. Vertical contact pins may be inserted from above into the anode paste instead of the inclined pins. Flexible connections 30 are made from the inclined pins 29 to a bus-bar 31 on each side of the electrode. The anode is supported from the lower contact pins 29 by suspension means 33 connected to jacking devices controlled by a wheel 34. Alumina is added to the furnace through bins 36. During operation of the furnace; the newly added croylite and alumina form a solidified crust between the bottom of the anode 24 and the vertical wall of the cavity 14 in the cathode 13 thereby forming an effective gas seal, so that furnace gases may be withdrawn by an exhaust blower through the electrode. Thin aluminium sheet may be used to obviate sticking between the anode mass and the walls of the casing or of the vane. Current is fed to the cathode by parallel rows of opposed contact rods 18 extending inwardly almost to the median line of the cathode.