Lithium extraction from ore by electrolysis

Abstract

Provided herein are a two-stage method and a system for extracting lithium from lithium ore. The method comprises extracting lithium from lithium ore and transferring the lithium to a molten metal, thereby forming a lithium-rich molten metal alloy, and transferring the lithium from the lithium-rich molten metal alloy to a conductive substrate.

What is claimed is: 
     
         1 . A method comprising:
 (a) contacting a source of lithium with a molten metal;   (b) extracting lithium from the source of lithium and transferring the lithium to the molten metal, thereby forming a lithium-rich molten metal alloy; and   (c) transferring the lithium from the lithium-rich molten metal alloy to a conductive substrate.   
     
     
         2 . The method of  claim 1 , wherein the source of lithium comprises a borate melt. 
     
     
         3 . The method of  claim 2 , further comprising, before (a), dissolving a material comprising lithium ions in the borate melt. 
     
     
         4 . The method of  claim 3 , wherein the material comprising lithium ions comprises a lithium ore. 
     
     
         5 . The method of  claim 4 , wherein the lithium ore comprises spodumene. 
     
     
         6 . The method of  claim 2 , wherein the borate melt comprises a fluoride salt. 
     
     
         7 . The method of  claim 6 , wherein the fluoride salt is selected from the group consisting of NaF, KF, CaF 2 , and combinations thereof. 
     
     
         8 . The method of  claim 2 , wherein the molten metal has a higher density than the borate melt. 
     
     
         9 . The method of  claim 1 , wherein (b) comprises applying a voltage across an anode and the molten metal. 
     
     
         10 . The method of  claim 1 , further comprising, before (c), contacting the lithium-rich molten metal alloy with a molten salt electrolyte. 
     
     
         11 . The method of  claim 10 , wherein (c) comprises applying a voltage across a cathode and the lithium-rich molten metal alloy, causing lithium ions to be released from the lithium-rich molten metal alloy and reduced to lithium metal at the cathode. 
     
     
         12 . The method of  claim 2 , wherein the borate melt is maintained at a temperature between 600° C. and 1000° C. 
     
     
         13 . The method of  claim 11 , wherein (c) is performed at a temperature between 300° C. and 800° C. 
     
     
         14 . The method of  claim 11 , wherein the cathode comprises an inert material. 
     
     
         15 . The method of  claim 14 , wherein the cathode comprises nickel, copper, titanium, and carbon. 
     
     
         16 . The method of  claim 10 , wherein the molten salt electrolyte comprises a salt selected from the group consisting of lithium halides, sodium halides, potassium halides, and combinations thereof. 
     
     
         17 . The method of  claim 16 , wherein the molten salt electrolyte comprises a salt selected from the group consisting of LiCl, KCl, RbCl, CsCl, SrCl 2 , BaCl 2 , and combinations thereof. 
     
     
         18 . The method of  claim 16 , wherein the molten salt electrolyte comprises fluoride salts. 
     
     
         19 . The method of  claim 18 , wherein the fluoride salts are selected from the group consisting of LiF, CaF 2 , and combinations thereof. 
     
     
         20 . The method of  claim 1 , wherein (a) and (b) are carried out in a first cell, and (c) is carried out in a second cell that is different from the first cell.