Production of specialty aluminum alloys using partition of feed impurities

Abstract

A series of inventions leading to the production of specific aluminum alloys (especially aluminum beverage can sheet product) through novel approach of introducing, selectively partitioning and managing alloying elements. This invention also enables manufacturing practices to enhance the performance characteristics of aluminum alloys produced. The selected elements can be derived from carbon anodes made from calcined petroleum coke with high metallic contents (such as nickel and vanadium). Alloying elements can also be introduced and managed from other raw material such as alumina and bath constituents added during aluminum smelting process. Additionally, cell operating parameters, such as cell temperature, off gas flow rate, aluminum tapping rate and impurity partition characteristics can also be manipulated to produce low cost aluminum alloys and facilitate utilization of high metallic content calcined petroleum coke.

1 . An improved aluminum base alloy suitable for forming into rigid container sheet products, the alloy comprised of 0.05 to 0.25 wt. % Cu, 0.8 to 1.4 wt. % Mn, 0.8 to 1.3 wt. % Mg, 0.05 to 0.15 wt. % V, max. 0.25 Zn, max 0.2 wt. % other impurities, with each impurity being not greater than 0.05 wt. %, the improved alloy in the worked condition having improved levels of strength and formability. 
   
   
       2 . The improved aluminum base alloy in accordance with  claim 1  wherein V is in the range of 0.01 to 0.25 wt. %. 
   
   
       3 . The improved aluminum base alloy in accordance with  claim 1  wherein the yield strength is at least 45 KSI and the tensile strength is at least 63 KSI. 
   
   
       4 . The improved aluminum base alloy in accordance with  claim 1  wherein the alloy sheet product has a grain size in the range of 30 to 200 microns. 
   
   
       5 . A method of providing improved aluminum alloy sheet product for forming into drawn and ironed beverage containers, the method comprising the steps of:
 (a) providing aluminum base alloy comprising 0.05 to 0.25 wt. % Cu, 0.8 to 1.4 wt. % Mn, 0.8 to 1.3 wt. % Mg, 0.05 to 0.15 wt. % V, max. 0.25 Zn, max 0.2 wt. % other impurities, with each impurity being not greater than 0.05 wt. %;   (b) casting the alloy into a solid product; and   (c) cold rolling and hot rolling said cast product into a sheet product having a thickness in the range of 0.1 to 0.2 inch, the sheet product having improved levels of strength and formability.   
   
   
       6 . The method in accordance with  claim 5  wherein V is in the range of 0.01 to 0.25 wt. %. 
   
   
       7 . The method in accordance with  claim 5  wherein the yield strength is at least 43 KSI and the tensile strength is at least 45 KSI. 
   
   
       8 . The method in accordance with  claim 5  wherein the alloy sheet product has a grain size in the range of 30 to 200 microns. 
   
   
       9 . A method of forming aluminum having relatively high levels of vanadium therein, the method comprising the steps of:
 (a) providing an electrolytic cell for producing aluminum, the cell containing an electrolyte, anode and cathode;   (b) adding alumina to said cell, said alumina containing 0.05% to 0.25% wt vanadium;   (c) passing electric current through said cell thereby depositing aluminum at the cathode;   (d) operating said method to concentrate said vanadium in the molten aluminum, said vanadium being present in the molten aluminum in the range of 0.01 to 0.25 wt. %;   (e) removing said aluminum from said cell; and   (f) alloying said aluminum and casting it into a cast product.   
   
   
       10 . The method in accordance with  claim 9  wherein petroleum cokes with high levels of vanadium 0.035 to 0.1 ppm and nickel 0.02 to 0.8 ppm are used to produce metal with the target alloy composition. 
   
   
       11 . The method in accordance with  claim 9  wherein fine particles are separated from the secondary alumina returning from the dry scrubber and these highly contaminated finer particles containing vanadium, iron, phosphorous, and nickel, are fed to a specific cell or cells to produce the target alloy composition. 
   
   
       12 . A method of operating a series of aluminum producing electrolytic cells to produce high purity aluminum and to produce vanadium containing aluminum of lesser purity, the method comprising:
 (a) providing a series of aluminum producing electrolytic cells indirectly having an anode, a cathode and containing an electrolyte;   (b) providing a series of alumina containing hoppers for feeding alumina to said cells;   (c) adding alumina from said hoppers to a corresponding cell;   (d) collecting fumes from each of said cells to provide collected fumes;   (e) drying scrubbing said collected fumes in one of said alumina containing hoppers to concentrate vanadium and impurities on the alumina to be fed to a specific electrolytic cell;   (f) operating said cells to produce high purity aluminum and vanadium enriched aluminum in the cell using alumina from the dry scrubber;   (g) keeping said high purity aluminum and vanadium enriched aluminum segregated; and   (h) casting said aluminum into high purity cast products and vanadium enriched cast products.   
   
   
       13 . A method wherein petroleum cokes with high levels of vanadium 0.035 to 0.1 ppm and nickel 0.02 to 0.8 ppm are used to produce metal with the target alloy composition. 
   
   
       14 . The method wherein fine particles are separated from the secondary alumina returning from the dry scrubber and these highly contaminated finer particles containing vanadium, iron, phosphorous, and nickel, are fed to a specific cell or cells to produce the target alloy composition.