Methods and systems for purifying metals or metal alloys

Abstract

Methods and systems for purifying metals or metal alloys are provided. The method comprises disposing a molten material comprising predominantly aluminum and at least one first metal having an atomic mass less than 13 in a first region of an electrolysis cell. The electrolysis cell comprises an anode, a cathode, and a molten salt electrolyte in contact with the anode and the cathode. The method comprises contacting the anode with the molten material, and applying an electrical voltage across the anode and the cathode such that at least a portion of the first metal in the molten material migrates to a third region in the electrolysis cell to produce a first material enriched in the first metal. The method comprises removing at least a first portion of the first material in the third region from the electrolysis cell.

What is claimed is: 
     
         1 . A method comprising:
 disposing a molten material comprising predominantly aluminum and at least one first metal having an atomic mass less than 13 in a first region of an electrolysis cell, the electrolysis cell comprising an anode, a cathode, and a molten salt electrolyte in contact with the anode and the cathode, wherein the molten salt electrolyte is disposed in a second region of the electrolysis cell;   contacting the anode with the molten material, and applying an electrical voltage across the anode and the cathode such that at least a portion of the first metal in the molten material migrates to a third region in the electrolysis cell to produce a first material enriched in the first metal, wherein the second region is intermediate the first region and the third region; and   removing at least a first portion of the first material in the third region from the electrolysis cell.   
     
     
         2 . The method of  claim 1 , further comprising heating a feedstock comprising an aluminum alloy to form the molten material. 
     
     
         3 . The method of  claim 2 , wherein the feedstock comprises machining chips comprising the aluminum alloy. 
     
     
         4 . The method of  claim 3 , further comprising cleaning the machining chips prior to heating the feedstock comprising the machining chips. 
     
     
         5 . The method of  claim 1 , further comprising removing at least a second material from the first region of the electrolysis cell, wherein the molten material comprises a first aluminum concentration based on a total weight of the molten material, the second material comprises a second aluminum concentration based on a total weight of the second material, and the second aluminum concentration is greater than the first aluminum concentration. 
     
     
         6 . The method of  claim 1 , further comprising casting the first portion removed from electrolysis cell into an ingot. 
     
     
         7 . The method of  claim 1 , further comprising introducing the first portion removed from the electrolysis cell into a furnace as a feedstock for producing a metal or metal alloy. 
     
     
         8 . The method of  claim 1 , wherein the anode and the cathode, individually, comprise at least one of a lithium wettable material, a beryllium wettable material, a sodium wettable material, and a magnesium wettable material. 
     
     
         9 . The method of  claim 1 , wherein the anode and cathode, individually, comprise a lithium wettable material. 
     
     
         10 . The method of  claim 1 , wherein a sum of lithium, beryllium, sodium, and magnesium in the molten material is 0.1% to 10%, by weight based on a total weight of the molten material. 
     
     
         11 . The method of  claim 1 , wherein the molten material comprises 0.1% to 5% lithium, by weight based on a total weight of the molten material. 
     
     
         12 . The method of  claim 11 , wherein the first portion removed from the third region of the electrolysis cell comprises at least 95% lithium, by weight based on a total weight of the first portion. 
     
     
         13 . The method of  claim 11 , wherein the molten salt electrolyte comprises a molten lithium salt. 
     
     
         14 . The method of  claim 1 , wherein the molten salt electrolyte comprises at least one of a molten lithium salt, a molten beryllium salt, a molten sodium salt, and a molten magnesium salt. 
     
     
         15 . The method of  claim 1 , wherein the method is a batch process. 
     
     
         16 . The method of  claim 1 , wherein the method is a continuous process. 
     
     
         17 . The method of  claim 1 , wherein the molten material has a first density, the molten salt electrolyte has a second density, the first material has a third density, the first density is greater than the second density, and the second density is greater than the third density. 
     
     
         18 . The method of  claim 1 , wherein the cathode extends from a first side of the electrolysis cell through the third region and into the second region, the anode extends from a second side of the electrolysis cell through the first region into the second region, the cathode does not contact the first region, and the anode does not contact the third region. 
     
     
         19 . The method of  claim 1 , further comprising providing an inert gaseous atmosphere within the electrolysis cell. 
     
     
         20 . A method comprising:
 disposing a molten material comprising predominantly aluminum and lithium in a first region of an electrolysis cell, the electrolysis cell comprising an anode, a cathode, and a molten salt electrolyte in contact with the anode and the cathode, wherein the molten salt electrolyte is disposed in a second region of the electrolysis cell;   contacting the anode with the molten material, and applying an electrical voltage across the anode and the cathode such that at least a portion of the lithium in the molten material migrates to a third region in the electrolysis cell to produce a first material enriched in the lithium, wherein the second region is intermediate the first region and the third region; and   removing at least a first portion of the first material in the third region from the electrolysis cell.   
     
     
         21 . A method comprising:
 feeding an aluminum-containing feedstock into an aluminum electrolysis cell;   directing an electric current into an anode through an electrolyte and into a cathode;   wetting at least a portion of a surface of the anode with a portion of the aluminum feedstock;   concomitant with directing the electric current, migrating at least a portion of at least one of lithium, beryllium, sodium, and magnesium in the aluminum feedstock to a location within the cell; and   removing the migrated lithium, beryllium, sodium, and magnesium from the cell, thereby producing a purified product.