Molten oxide electrolysis methods and related systems

Abstract

Molten oxide electrolysis may be used for extracting one or more metals from a mixture of metal oxides. The mixture of metal oxides may be complex and include at least three metal oxides, each present at 0.5 wt % or greater based on a total weight of the metal oxide electrolyte precursor, to produce a metal oxide electrolyte. In some instances, two or more metals may be extracted in a series of molten oxide electrolysis process where metal oxides having higher Gibbs free energy of formation at 1500° C. are preferentially reduced in each respective molten oxide electrolysis unit before metal oxides having lower Gibbs free energy of formation at 1500° C.

What is claimed is: 
     
         1 . A method for extracting metal from a complex metal oxide electrolyte, the method comprising:
 changing a concentration of at least one metal oxide in a metal oxide electrolyte precursor comprising at least three metal oxides, each present at 0.5 wt % or greater based on a total weight of the metal oxide electrolyte precursor, to produce a metal oxide electrolyte; and   performing molten oxide electrolysis with the metal oxide electrolyte in a molten oxide electrolysis unit to extract a metal of one or more of the metal oxides of the metal oxide electrolyte.   
     
     
         2 . The method of  claim 1 , wherein the metal oxide electrolyte comprises at least one of: a mining waste or metallurgical waste. 
     
     
         3 . The method of  claim 1 , wherein the metal oxide of the metal extracted is present at 10 wt % or less based on a total weight of the metal oxide electrolyte. 
     
     
         4 . The method of  claim 1 , wherein the metal oxide of the metal extracted is present at 3 wt % or less based on a total weight of the metal oxide electrolyte. 
     
     
         5 . The method of  claim 1 , wherein the at least three metal oxides, each present at 0.5 wt % or greater is at least six metal oxides, each present at 0.5 wt % or greater based on a total weight of the metal oxide electrolyte precursor. 
     
     
         6 . The method of  claim 5 , wherein the at least three metal oxides, each present at 0.5 wt % or greater includes (a) a third metal oxide present at 4 wt % or greater, (b) a fourth metal oxide and a fifth metal oxide each present at 1 wt % or greater, and (c) at least three additional metal oxides each present at 0.5 wt % or greater, each based on a total weight of the metal oxide electrolyte precursor. 
     
     
         7 . The method of  claim 1 , wherein a cathode of the molten oxide electrolysis comprises iron in a molten state, and wherein the metal extracted comprises an iron niobium alloy, an iron tantalum alloy, or an iron chromium alloy. 
     
     
         8 . The method of  claim 1 , wherein the at least three metal oxides comprises 0.5 wt % to 20 wt % Nb 2 O 5 , 25 wt % to 35 wt % SiO 2 , 1 wt % to 25 wt % ZrO 2 , 10 wt % to 25 wt % CaO, 0.5 wt % to 10 wt % MgO, 1 wt % to 15 wt % Al 2 O 3 , 0.5 wt % to 10 wt % Fe 2 O 3 , 1 wt % to 10 wt % TiO 2  and 0.5 wt % to 3 wt % Ta 2 O 5 , and wherein the metal extracted is Nb. 
     
     
         9 . The method of  claim 1 , wherein the at least three metal oxides, each present at 0.5 wt % or greater includes a first metal oxide present at 20 wt % or greater, a second metal oxide present at 10 wt % or greater, a third metal oxide present at 10 wt % or greater, and at least 3 additional metal oxides each present at 1 wt % or greater, based on a total weight of the metal oxide electrolyte precursor. 
     
     
         10 . The method of  claim 1 , wherein the at least three metal oxides, each present at 0.5 wt % or greater includes 3 metal oxides, each present at 15 wt % or greater, 1 metal oxide present at 5 wt % or greater, and at least 2 additional metal oxides each present at 1 wt % or greater, based on a total weight of the metal oxide electrolyte precursor. 
     
     
         11 . The method of  claim 1 , wherein a cathode of the molten oxide electrolysis comprises iron in a molten state, and wherein the metal extracted comprises an iron manganese alloy. 
     
     
         12 . The method of  claim 1 , wherein the metal oxide electrolyte comprises a metal not as a metal oxide at 0.5 wt % to 20 wt %. 
     
     
         13 . The method of  claim 1 , wherein the changing of the concentration of the at least one metal oxide comprises smelting the metal oxide electrolyte precursor and optionally refining the metal oxide electrolyte precursor. 
     
     
         14 . The method of  claim 1 , wherein the changing of the concentration of the at least one metal oxide comprises adding one or more metal oxide additives to the metal oxide electrolyte precursor. 
     
     
         15 . A method for performing molten oxide electrolysis, the method comprising:
 providing a metal oxide feedstock comprising at least three metal oxides, each present at 0.5 wt % or greater based on a total weight of the metal oxide feedstock;   conditioning the metal oxide feedstock, to produce a metal oxide electrolyte, wherein the conditioning comprises at least one of: (a) changing a concentration of at least one the at least three metal oxides in the metal oxide feedstock and (b) changing a concentration of at least one metal in a metal oxide feedstock; and   performing molten oxide electrolysis on the metal oxide electrolyte as an electrolyte to produce (a) a spent electrolyte having a reduced concentration of a first metal oxide of the at least three metal oxides as compared to a concentration of the first metal oxide in the metal oxide electrolyte, and (b) a metal product comprising a first metal of the first metal oxide.   
     
     
         16 . The method of  claim 15 , wherein the metal oxide electrolyte comprises at least one of: a mining waste or metallurgical waste. 
     
     
         17 . The method of  claim 15 , wherein the first metal oxide is present at 10 wt % or less based on a total weight of the metal oxide electrolyte. 
     
     
         18 . The method of  claim 15 , wherein the metal oxide of the metal extracted is present at 3 wt % or less based on a total weight of the metal oxide electrolyte. 
     
     
         19 . The method of  claim 15 , wherein the at least three metal oxides, each present at 0.5 wt % or greater is at least six metal oxides, each present at 0.5 wt % or greater based on a total weight of the metal oxide feedstock. 
     
     
         20 . The method of  claim 15 , wherein the at least three metal oxides, each present at 0.5 wt % or greater includes a second metal oxide present at 20 wt % or greater, a third metal oxide present at 10 wt % or greater, a fourth metal oxide present at 10 wt % or greater, and at least 3 additional metal oxides, including the first metal oxide, each present at 1 wt % or greater, based on a total weight of the metal oxide feedstock.