Process for separating undesirable metals

Abstract

Disclosed herein are processes and systems relating to separation, handling, and disposal of undesirable metals to facilitate recovery of desirable metals, including lithium. Undesirable metals may be precipitated at high pH and separated from a liquid resource to facilitate recovery of the desirable metals. The precipitated undesirable metals may then be redissolved and recombined with the liquid resource for disposal.

What is claimed is: 
     
         1 . A process for recovering a desirable metal from a liquid resource, the process comprising:
 a) precipitating an undesirable metal from the liquid resource to form an undesirable metal precipitate;   b) separating said undesirable metal precipitate from the liquid resource to form a feed liquid;   c) recovering said desirable metal from the feed liquid to form a raffinate; and   d) redissolving said undesirable metal precipitate into said raffinate to form a raffinate mixture.   
     
     
         2 . The process of  claim 1 , wherein said recovering comprises contacting said feed liquid with ion exchange particles that absorb said desirable metal while releasing protons. 
     
     
         3 . The process of  claim 1 , wherein said desirable metal comprises lithium. 
     
     
         4 . The process of  claim 1 , wherein said undesirable metal comprises a transition metal. 
     
     
         5 . The process of  claim 1 , wherein said precipitating comprises adding a base, an oxidant, or both, to the liquid resource. 
     
     
         6 . The process  claim 1 , wherein said precipitating comprises adding NaOH, Ca(OH) 2 , or both, to the liquid resource. 
     
     
         7 . The process of  claim 1 , wherein said redissolving comprises combining an acid with said undesirable metal precipitate. 
     
     
         8 . The process of  claim 7 , wherein said combining an acid with said undesirable metal precipitate occurs 1) prior to combining said undesirable metal precipitate with said raffinate, or 2) after combining said undesirable metal precipitate with said raffinate. 
     
     
         9 . The process of  claim 7 , wherein the acid comprises hydrochloric acid, sulfuric acid, or both. 
     
     
         10 . The process of  claim 1 , wherein said precipitating comprises adding a base to the liquid resource, wherein said redissolving comprises combining an acid with said undesirable metal precipitate, wherein said acid, said base, or both are produced 1) with an electrochemical cell, or 2) from a salt solution. 
     
     
         11 . The process of  claim 10 , wherein said salt solution comprises a sodium chloride solution, wherein said acid, said base, or both, are produced by processing said sodium chloride solution into a hydrochloric acid solution and/or a sodium hydroxide solution, wherein the hydrochloric acid solution comprises said acid and the sodium hydroxide solution comprises said base. 
     
     
         12 . The process of  claim 1 , wherein said separating of the undesirable metal precipitate comprises filtration, gravity sedimentation, centrifugal sedimentation, magnetic fields, other methods of solid-liquid separation, or any combination thereof 
     
     
         13 . The process of  claim 12 , wherein said separating of the undesirable metal precipitate comprises using a filter, a settling tank, a clarifier, a hydrocyclone, a centrifuge, or combinations thereof. 
     
     
         14 . The process of  claim 13 , wherein said separating of the undesirable metal precipitate comprises using a centrifuge. 
     
     
         15 . The process of  claim 1 , further comprising injecting the raffinate mixture underground. 
     
     
         16 . The process of  claim 1 , further comprising injecting the raffinate mixture into 1) a reservoir from where the liquid resource is obtained, 2) a different reservoir from the liquid resource is obtained, or 3) both. 
     
     
         17 . A process for separating an undesirable metal from a liquid resource, the process comprising:
 a) adding a base to said liquid resource to precipitate said undesirable metal, thereby forming an undesirable metal precipitate;   b) separating said undesirable metal precipitate from said liquid resource to form a feed liquid;   c) recovering a desirable metal from the feed liquid; and   d) combining an acid to said undesirable metal precipitate to form a solution of redissolved undesirable metals for disposal.   
     
     
         18 . The process of  claim 17 , wherein said recovering comprises contacting said feed liquid with ion exchange particles that absorbs said desirable metal while releasing protons. 
     
     
         19 . The process of  claim 17 , wherein said desirable metal comprises lithium. 
     
     
         20 . The process of  claim 17 , wherein said undesirable metal comprises a transition metal. 
     
     
         21 . The process of  claim 17 , further comprising adding an oxidant with said base to said liquid resource. 
     
     
         22 . The process of  claim 17 , wherein said base comprises NaOH, Ca(OH) 2 , or both. 
     
     
         23 . The process of  claim 17 , wherein the acid comprises hydrochloric acid, sulfuric acid, or both. 
     
     
         24 . The process of  claim 17 , wherein said acid, said base, or both, are produced 1) with an electrochemical cell, or 2) from a salt solution. 
     
     
         25 . The process of  claim 24 , wherein said salt solution comprises a sodium chloride solution, wherein said acid, said base, or both, are produced by processing said sodium chloride solution into a hydrochloric acid solution and/or a sodium hydroxide solution, wherein the hydrochloric acid solution comprises said acid and the sodium hydroxide solution comprises said base. 
     
     
         26 . The process of  claim 17 , wherein said separating of the undesirable metal precipitate comprises filtration, gravity sedimentation, centrifugal sedimentation, magnetic fields, other methods of solid-liquid separation, or any combination thereof 
     
     
         27 . The process of  claim 26 , wherein said separating of the undesirable metal precipitate comprises using a filter, a settling tank, a clarifier, a hydrocyclone, a centrifuge, or combinations thereof 
     
     
         28 . The process of  claim 27 , wherein said separating of the undesirable metal precipitate comprises using a centrifuge. 
     
     
         29 . The process of  claim 17 , wherein said disposal comprises injecting the solution of redissolved undesirable metals underground. 
     
     
         30 . The process of  claim 17 , wherein said disposal comprises injecting the solution of redissolved undesirable metals into 1) a reservoir from where the liquid resource is obtained, 2) a different reservoir from the liquid resource is obtained, or 3) both.