Patent ID: 8480876

Claim:
A method of producing aluminum in an electrolytic cell containing alumina dissolved in the electrolyte, the method comprising the steps of: (a) providing a molten salt electrolyte having dissolved alumina and excess of alumina particles as a slurry therein in an electrolytic cell having an anodic liner for containing said electrolyte, said liner having an anodic bottom and walls including at least one end wall extending upwardly from said bottom, said anodic liner being substantially inert with respect to said molten electrolyte; (b) providing a plurality of non-consumable anodes disposed substantially vertically in said electrolyte and a plurality of cathodes disposed vertically in said electrolyte, said anodes and said cathodes arranged in alternating relationship, said anodes electrically connected to said anodic liner, said cathodes comprised of a porous base suitable for passing molten aluminum therethrough, said porous base material having a micro-porous, electrically conductive layer on the surface thereof wet by molten aluminum and suited for depositing aluminum thereon and for separating said molten aluminum from said molten electrolyte during operation of the cell; (c) passing an electric current through said anodic liner to said anodes, through said electrolyte to said cathodes, depositing aluminum on said cathodes, and generating oxygen bubbles at the anodes and said anodic liner, said bubbles stirring said electrolyte; (d) passing molten aluminum through said porous base comprising said cathode; (e) collecting molten aluminum from said cathodes in a tubular member, said tubular member in liquid communication with each cathode to collect molten aluminum therefrom; and (f) delivering molten aluminum by siphoning through said tubular member to a molten aluminum container.