Cathode for aluminum producing electrolytic cell
AssigneeNorthwest Aluminum Technologies
InventorCraig W. Brown
Life of this patent
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Abstract
A method of producing aluminum in an electrolytic cell comprising the steps of providing an anode in a cell, preferably a non-reactive anode, and also providing a cathode in the cell, the cathode comprised of a base material having low electrical conductivity reactive with molten aluminum to provide a highly electrically conductive layer on the base material. Electric current is passed from the anode to the cathode and alumina is reduced and aluminum is deposited at the cathode. The cathode base material is selected from boron carbide, and zirconium oxide.
Claims22
A method of producing aluminum in a low temperature electrolytic cell comprising the steps of:
- (a) providing a molten electrolyte at temperature less than 900° C. in an electrolytic cell having alumina dissolved in said electrolyte;
- (b) providing a substantially non-reactive anode in said cell;
- (c) providing a cathode in said cell, the cathode comprised of a base material having a high electrical resistivity and reactive with molten aluminum to provide a layer on said base material wettable with molten aluminum;
- (d) passing electric current from said anode through said electrolyte to said cathode;
- and
- (e) reducing said alumina and depositing aluminum on said cathode.
A method of producing aluminum in an electrolytic cell comprising:
- (a) providing a molten electrolyte in an electrolytic cell having alumina dissolved therein;
- (b) providing an anode and a cathode in said electrolyte in said cell, said cathode comprised of:
- (i) a base material comprised of boron carbide:
- (ii) a layer of aluminum carbide on said base material, said layer formed by reacting aluminum with said boron carbide in said base material, said aluminum carbide layer wettable with molten aluminum;
- and
- (iii) a layer of aluminum provided on said layer of aluminum carbide;
- (c) passing electric current from said anode through said electrolyte to said cathode;
- and
- (d) reducing said alumina and depositing aluminum on said cathode.
A method of producing aluminum in a low temperature electrolytic cell comprising the steps of:
- (a) providing molten electrolyte at a temperature range of 660° to 800° C. in an electrolytic cell having alumina dissolved in said electrolyte;
- (b) providing a substantially inert anode in said electrolyte;
- (c) passing electric current from said anode through said electrolyte to a cathode immersed in said electrolyte, the cathode comprised of a boron carbide base material reactive with molten aluminum providing a reactive layer on said base material wettable by molten aluminum provided as a layer on the reactive layer;
- and
- (d) reducing said alumina and depositing aluminum on the cathode.
A method of preparing a cathode for use in the production of aluminum in an electrolytic cell employing a molten electrolyte having alumina dissolved therein comprising:
- (a) providing a base material comprised of boron carbide;
- and
- (b) contacting a surface of the base material with aluminum to provide a coating of aluminum thereon that reacts with said surface when said aluminum is molten.
A method of forming a boron carbide based cathode for use in the production of aluminum in a molten electrolyte having aluminum dissolved therein comprising:
- (a) providing a base material comprised of boron carbide;
- and
- (b) reacting said base material with aluminum to form a layer thereon containing aluminum boride wettable with molten aluminum.
A refractory composite cathode for use in an aluminum producing electrolytic cell, said cell employing a molten electrolyte containing alumina dissolved therein, the cathode comprised of:
- (a) base material having high electrical resistivity;
- and
- (b) a layer of an aluminum compound provided on said base material to provide a layer thereon wettable with molten aluminum.
Dependencies are inferred from the claim text.