Process and apparatus for production of aluminum

A process for the production of aluminum comprising the steps of:

• forming in a cell body an electrolytic bath in which alumina is dissolved in a fused fluoride salt bath mainly composed of cryolite;
• conducting a current from a self-baking type carbon anode, which is located above said cell body, to said cell body serving also as a cathode, thereby simultaneously conducting the baking of unbaked carbonaceous raw material in the carbon anode and the electrolytic reduction of alumina;
• maintaining the immersion of said carbon anode in the electrolytic bath above the molten aluminum which is formed on the cell body as a result of electrolysis;
• feeding alumina in accordance with the decrease in the alumina concentration of the electrolytic bath;
• introducing a gas to the lower surface of said carbon anode which is in contact with the electrolytic bath via at least one aperture passing in an essentially vertical direction through the carbon anode;
• and
• intermittently introducing the gas from said at least one aperture to the lower surface of the carbon anode during normal operation of the cell when the alumina concentration is higher than a critical alumina concentration so that an anode effect is not generated, thereby reducing the cell voltage or increasing the inter-electrode distance of an aluminum electrolytic cell.