Method for the regeneration of sorbent materials

Abstract

The process of the present invention is directed to the use of sulfuric acid and/or an organic acid to regenerate spent sorbent from a metal recovery process. The sorbent can be activated carbon.

What is claimed is:  
     
         1 . A process for recovering a metal from a metal-containing material, comprising: 
 (a) leaching the material to form a pregnant leach solution containing at least a portion of the metal,    (b) contacting the pregnant leach solution with a sorbent to form a loaded sorbent containing at least a portion of the metal,    (c) contacting the loaded sorbent with an eluant to form a loaded eluant containing at least a portion of the metal in the loaded sorbent and a spent sorbent,    (d) contacting the spent sorbent with an organic acid or sulfuric acid to form a regenerated sorbent, and    (e) recovering the metal from the loaded eluant.    
     
     
         2 . The process of    claim 1   , wherein the sorbent is at least one of carbon, and resin.  
     
     
         3 . The process of    claim 1   , wherein step (a) is performed by contacting a lixiviant with the material and wherein the lixiviant includes at least of cyanide, thiosulfate, thiourea, thiocyanate and mixtures thereof.  
     
     
         4 . The process of    claim 1   , wherein the eluant includes at least one of a carbohydrate, a hydroxide, a cyanide, an alcohol, a ketone, a nitrile, acetone, a cyanate, a hydrazine, a hydroxy acid, a carboxylic acid, a hydroxycarboxylic acid, a hydrocarbon, ammonia, and mixtures thereof.  
     
     
         5 . The process of    claim 1   , wherein the metal is a member of at least one of Groups VIIIA, IB, or IIB of the Periodic Table of the Elements.  
     
     
         6 . The process of    claim 1   , wherein the organic acid is one or more hydroxy acids.  
     
     
         7 . The process of    claim 6   , wherein the hydroxy acid is one or more hydroxycarboxylic acids.  
     
     
         8 . The process of    claim 1   , wherein the regenerated sorbent is reused in step (b).  
     
     
         9 . The regenerated sorbent made in the process of    claim 1   .  
     
     
         10 . The metal recovered in the process of    claim 1   .  
     
     
         11 . A process for treating spent carbon, comprising contacting the spent carbon with an organic acid.  
     
     
         12 . The process of    claim 11   , further comprising: 
 (a) leaching the material with a lixiviant to form a pregnant leach solution containing at least a portion of the metal,    (b) contacting the pregnant leach solution with a sorbent to form a loaded sorbent containing at least a portion of the metal,    (c) contacting the loaded sorbent with an eluant to form a loaded eluant containing at least a portion of the metal in the loaded sorbent and a spent sorbent, wherein the lixiviant includes at least one of cyanide, thiosulfate, and mixtures thereof, and the eluant includes at least one of a carbohydrate, ammonia, a hydroxide, a cyanide, an alcohol, a ketone, a nitrile, acetone, a cyanate, a hydrazine, a hydroxy acid, a carboxylic acid, a hydroxycarboxylic acid, a hydrocarbon, and mixtures thereof.    
     
     
         13 . The process of    claim 11   , wherein the metal is a member of at least one of Groups VIIIA, IB, OR IIB of the Periodic Table of the Elements.  
     
     
         14 . The process of    claim 11   , wherein the organic acid is one or more hydroxy acids.  
     
     
         15 . The process of    claim 14   , wherein the hydroxy acid is one or more hydroxycarboxylic acids.  
     
     
         16 . The process of    claim 15   , wherein the hydroxycarboxylic acid is selected from the group consisting essentially of glycolic acid, lactic acid, and mixtures thereof.  
     
     
         17 . The process of    claim 12   , wherein the regenerated sorbent is reused in step (c).  
     
     
         18 . The regenerated sorbent made in the process of    claim 11   .  
     
     
         19 . The metal recovered in the process of    claim 11   .  
     
     
         20 . The process of    claim 11   , further comprising: 
 contacting the spent carbon with a metal-containing solution to form a metal loaded carbon;    contacting the metal loaded carbon with at least one of an organic and inorganic acid to form a treated metal loaded carbon; and    contacting the treated metal loaded carbon with an eluant.    
     
     
         21 . Regenerated carbon for reuse in an elution process, comprising an organic acid adsorbed in a plurality of pores of the carbon.  
     
     
         22 . The regenerated carbon of    claim 21   , wherein the organic acid is a hydroxy acid.  
     
     
         23 . The regenerated carbon of    claim 22    wherein the hydroxycarboxylic acid is selected from the group consisting of glycolic acid, lactic acid, and mixtures thereof.  
     
     
         24 . The regenerated carbon of    claim 22   , wherein regenerated carbon includes both the sulfuric acid and the organic acid.  
     
     
         25 . The regenerated carbon of    claim 22   , wherein the regenerated carbon includes a hydroxycarboxylic acid.  
     
     
         26 . A process for eluting a metal from a sorbent, comprising: 
 contacting a metal-loaded sorbent with an organic acid or sulfuric acid to form a treated metal-loaded carbon; and    contacting the treated metal-loaded carbon with an eluant to form a barren sorbent and a metal-loaded eluant containing at least most of the metal loaded onto the metal-loaded sorbent.    
     
     
         27 . The process of    claim 26   , wherein the organic acid is a hydroxy acid.  
     
     
         28 . The process of    claim 26   , wherein the hydroxy acid is selected from the group consisting of glycolic acid, lactic acid, and mixtures thereof.  
     
     
         29 . The process of    claim 26   , wherein the sorbent is at least one of activated carbon, a resin, and mixtures thereof.