Patent ID: 9217204
Filing Date: 2015-12-22
Classification: C25C

Abstract:
1. A method for electrolytic production of aluminium metal, said method comprising performing electrolysis on an electrolyte comprising aluminium oxide in a molten fluoride electrolyte at a temperature in a range of 680° C. to 980° C. in an electrolysis cell containing at least one electrolysis chamber with at least one essentially inert anode aligned vertically or vertically inclined and at least one wettable cathode aligned vertically or vertically inclined, and/or at least one bipolar electrode containing both anode and cathode, where the anode evolves oxygen gas and the cathode has aluminium discharged thereonto in the electrolysis process, the oxygen gas enforcing an electrolyte flow pattern upward and the produced aluminium flowing downward due to gravity, controlling and maintaining the temperature of an electronic active surface of each of the anode and the cathode independently of each other and further at a level different from the level of the surrounding electrolyte by active or passive cooling and/or active or passive heating, and controlling a temperature of the surrounding electrolyte independently from said controlling and maintaining of the temperature of the electronic active surface of each of the anode and the cathode, so as to allow a dissolution of the aluminium oxide in the electrolyte to be optimized, while limiting a dissolution of the anode in the electrolyte and preventing a formation of solid deposits at the cathode, wherein the temperature of the active surface of the anode is colder than the temperature of the active surface of the cathode.