Anode for use in aluminum producing electrolytic cell

Abstract

A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900° C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable Cu—Ni—Fe—Sn anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

1 . A method of producing aluminum in an electrolytic cell containing: alumina dissolved in an electrolyte, the method comprising the steps of;
 (a) providing a molten salt electrolyte at a temperature of less than 900° C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, said liner having a bottom and walls extending upwardly from said bottom;   (b) providing a plurality of substantially non-consumable anodes and cathodes disposed in a generally vertical direction in said electrolyte, said anodes comprised of a Cu—Ni—Fe—Sn alloy; and   (c) passing electrical current through said anodes and through said electrolyte to said cathodes for purposes of electrolysis, depositing aluminum at said cathodes and producing gas at said anodes.   
   
   
       2 . The method in accordance with  claim 1  wherein said anode comprises 10 to 70 wt. % Cu, 15 to 50 wt. % Ni, and 1 to 15 wt. % Sn, the remainder Fe. 
   
   
       3 . The method in accordance with  claim 1  wherein said anode comprises 10 to 20 wt. % Cu, 20 to 30 wt. % Ni, and 2 to 5 wt. % Sn, the remainder Fe. 
   
   
       4 . The method in accordance with  claim 1  wherein said anode comprises 10 to 20 wt. % Cu, 20 to 30 wt. % Ni, and 2 to 5 wt. % Sn, and 50 to 70 wt. % Fe. 
   
   
       5 . The method in accordance with  claim 1  wherein said electrolyte is comprised of one or more alkali metal fluorides. 
   
   
       6 . The method in accordance with  claim 1  wherein said electrolyte is comprised of one or more alkali metal fluorides and aluminum fluoride. 
   
   
       7 . The method in accordance with  claim 1  including maintaining said electrolyte in a temperature range of about 660° to 8 60° C. 
   
   
       8 . The method in accordance with  claim 1  wherein said electrolyte has a melting point in the range of 715° to 860° C. 
   
   
       9 . The method in accordance with  claim 1  including passing an electric current through said cell at a current density in the range of 0.1 to 1.5 A/cm 
   
   
       10 . The method in accordance with  claim 9  wherein said cathodes are selected from the group consisting of titanium diboride, zirconium diboride, titanium carbide, zirconium carbide and molybdenum. 
   
   
       11 . The method in accordance with  claim 1  wherein said anodes and cathodes have planar surfaces arranged in a vertical orientation in said electrolyte and wherein said anodes and cathodes are arranged in alternating relationship. 
   
   
       12 . The method in accordance with  claim 1  including adding alumina to said cell on a substantially continuous basis. 
   
   
       13 . The method in accordance with  claim 1  including collecting aluminum from said cathode in the bottom of said cell. 
   
   
       14 . The method in accordance with  claim 1  including maintaining alumina in said electrolyte in a range of 2 to 6 wt. %. 
   
   
       15 . A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of;
 (a) providing a molten salt electrolyte having a melting point in the range of 715° to 900° C. and having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, said liner having a bottom and walls extending upwardly from said bottom;   (b) providing a plurality of anodes and cathodes disposed in a generally vertical direction in said electrolyte, said anodes comprised of 10 to 70 wt. % Cu, 15 to 50 wt. % Ni, 1 to 15 wt. % Sn, the remainder Fe, said cathodes having a planar surface disposed opposite an anode planar surface, said cathodes' and said anodes' planar surfaces defining a region therebetween; and   (c) passing electrical current through said anodes and through said electrolyte to said cathodes, depositing aluminum at said cathodes and producing gas at said anodes.   
   
   
       16 . A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of;
 (a) providing a molten salt electrolyte having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, said liner having a bottom and walls extending upwardly from said bottom;   (b) adding alumina to said electrolyte on a continuous basis to provide an alumina-enriched electrolyte;   (c) providing a plurality of substantially non-consumable anodes and cathodes disposed in said electrolyte, said anodes comprised of an alloy containing Cu—Ni—Sn, the remainder Fe;   (d) flowing alumina-enriched electrolyte between said anodes and said cathodes; and   (e) passing electrical current through said anodes and through said electrolyte to said cathodes, depositing aluminum at said cathodes and producing gas at said anodes.   
   
   
       17 . An improved anode for use in an electrolytic cell for producing aluminum from alumina dissolved in a molten salt electrolyte contained in said cell wherein aluminum is deposited at the cathode, oxygen is produced at the anode when electric current is passed through the cell, said cell containing at least one cathode and one anode disposed in said electrolyte, said anode comprised of an alloy, said cathode having a surface, said anode having a surface for disposing opposite said cathode surface to provide an anode-cathode distance defining a region between said anode and said cathode surfaces, said anode comprised of a Cu—Ni—Fe—Sn alloy. 
   
   
       18 . The anode in accordance with  claim 17  wherein said anode is comprised of 10 to 70 wt. % Cu, 15 to 60 wt. % Ni, 1 to 15 wt. % Sn, the remainder Fe, incidental elements and impurities. 
   
   
       19 . The anode in accordance with  claim 17  wherein said anode is comprised of 10 to 20 wt. % Cu, 20 to 30 wt. % Ni, and 2 to 5 wt. % Sn, the remainder Fe, incidental elements and impurities. 
   
   
       20 . The anode in accordance with  claim 17  wherein said anode is comprised of 10 to 70 wt. % Cu, 15 to 50 wt. % Ni, 1 to 15 wt. % Sn, and 15 to 75 wt. % Fe, incidental elements and impurities. 
   
   
       21 . In an improved method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte wherein a molten salt electrolyte is maintained at a temperature of less than 900° C., the electrolyte having alumina dissolved therein, and alumina add to the electrolyte on a continuous basis to provide alumina-enriched electrolyte, and wherein a plurality of non-consumable anodes and cathodes are disposed in a vertical direction in said electrolyte, said cathodes having a flat surface, the improved method comprising;
 (a) providing anodes having a planar surface disposed opposite the flat surface of the cathode to define a region between the cathode flat surface and the planar surface of the anode, said anodes comprised of a Cu—Ni—Fe—Sn alloy;   (b) passing electrical current through said anodes and through said electrolyte to said cathodes, depositing aluminum at said cathodes and producing gas at said anodes.   
   
   
       22 . An electrolytic cell for producing aluminum from alumina dissolved in an electrolyte, the cell comprised of;
 (a) a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom and means for adding alumina to said cell to provide alumina-enriched electrolyte;   (b) a plurality of non-consumable anodes and cathodes disposed in said electrolyte contained in said cell, said anodes comprised of a Cu—Ni—Fe—Sn alloy, said cathodes having a cathode surface, said anodes having an anode surface disposed from said cathode surface to define a region between said anode and cathode to permit flow of electrolyte therethrough to provide alumina-enriched electrolyte to said region between said anodes and said cathodes; and   (c) means for passing electrical current through said anodes and through said electrolyte to said cathodes for producing aluminum at said cathode and gas at said anodes.   
   
   
       23 . The cell in accordance with  claim 22  wherein said cathode surface is a planar surface. 
   
   
       24 . The cell in accordance with  claim 22  wherein said anode surface is a planar surface. 
   
   
       25 . The cell in accordance with  claim 22  wherein said anode and said cathode have an active area ratio anode to cathode in the range of 1.1:1 to 5:1. 
   
   
       26 . The anode in accordance with  claim 22  wherein said anode is comprised of 10 to 20 wt. % Cu, 20 to 30 wt. % Ni, and 2 to 5 wt. % Sn, the remainder Fe, incidental elements and impurities. 
   
   
       27 . The anode in accordance with  claim 22  wherein said anode is comprised of 10 to 70 wt. % Cu, 15 to 50 wt. % Ni, 1 to 15 wt. % Sn, and 15 to 75 wt. % Fe, incidental elements and impurities. 
   
   
       28 . The cell in accordance with  claim 22  wherein the anodes have two planar surfaces, each planar surface disposed opposite a surface of said cathode, permitting flow of alumina-enriched electrolyte to the region between said anodes and said cathodes. 
   
   
       29 . An anode having increased anode active surface area for use in an electrolytic cell for producing aluminum from alumina dissolved in a molten salt electrolyte contained in the cell, the cell containing at least one cathode and one anode disposed in said electrolyte, said anode comprised of a Cu—Ni—Fe—Sn alloy, said cathode having a surface, the anode having a first surface for disposing opposite said cathode surface to provide a controlled anode-cathode distance defining a region between said anode and said cathode surfaces. 
   
   
       30 . The anode in accordance with  claim 29  wherein said anode surface is a planar surface. 
   
   
       31 . The anode in accordance with  claim 29  wherein said first surface of said anode is a planar surface. 
   
   
       32 . The anode in accordance with  claim 29  wherein said anode is comprised of 10 to 20 wt. % Cu, 20 to 30 wt. % Ni, and 2 to 5 wt. % Sn, the remainder Fe, incidental elements and impurities. 
   
   
       33 . The anode in accordance with  claim 29  wherein said anode is comprised of 10 to 70 wt. % Cu, 15 to 50 wt. % Ni, 1 to 15 wt. % Sn, and 15 to 75 wt. % Fe, incidental elements and impurities.