Patent ID: 6866767

Claim:
A method of preventing an anode effect from occurring during the production of aluminum in an electrolytic cell containing a molten electrolyte including alumina and having one or more carbon-containing anodes, wherein a crust forms over the electrolyte which crust is broken along the sides of the cells in full crust breakings at intervals of about 4 to 12 hours and between the said full crust breakings an amount of alumina is added sufficient to sustain the electrolysis for the period of time between the full crust breakings, characterized in that about 50 to 90% of the theoretical amount of alumina between the full crust breakings is added to the cell within a short time following a full crust breaking, the electrical resistance within the electrolyte is continuously monitored between crust breakings, and when the detected resistance begins to rapidly increase indicating the approach of an anode effect, the anodes are activated into a pumping action thereby breaking the crust adjacent the anodes, allowing alumina to flow into the molten electrolyte and also creating a stirring action within the molten electrolyte, whereby the resistance is lowered and any anode effect is avoided until the next full crust breaking.