System and Method for Recovery of Nickel Values From Nickel-Containing Ores

Abstract

A method is provided for extracting nickel values from nickel-containing ores. The method comprises (a) treating a nickel-containing ore with an acid, thereby producing an acid treated ore; (b) baking the acid treated ore, thereby producing a baked ore; (c) leaching nickel from the baked ore to form a leachate; and (d) extracting nickel values from the leachate through the use of an ion exchange resin.

1 . A method for extracting nickel values from nickel-containing ores, the method comprising:
 treating a nickel-containing ore with an acid, thereby producing an acid treated ore;   baking the acid treated ore, thereby producing a baked ore;   leaching nickel from the baked ore to form a leachate; and   
       extracting nickel values from the leachate through the use of an ion exchange resin. 
     
     
         2 . The method of  claim 1 , further comprising:
 electrolytically depositing the extracted nickel values.   
     
     
         3 . The method of  claim 2 , wherein electrolytically depositing the extracted nickel values includes electrowinning. 
     
     
         4 . The method of  claim 1 , wherein the acid treated ore is baked in an oxidizing environment. 
     
     
         5 . The method of  claim 4 , wherein the baked ore contains an iron content of at least 15% by weight. 
     
     
         6 . The method of  claim 5 , further comprising adding an iron ore to the acid treated ore prior to baking the acid treated ore. 
     
     
         7 . The method of  claim 6 , wherein adding an iron ore to the acid treated ore includes recycling an iron-containing residue from another ore extraction process. 
     
     
         8 . The method of  claim 1 , wherein leaching nickel from the baked ore is catalyzed by a material selected from the group consisting of fluorides and chlorides. 
     
     
         9 . The method of  claim 1 , wherein leaching nickel from the baked ore includes leaching scandium from the baked ore such that the leachate contains nickel and scandium values. 
     
     
         10 . The method of  claim 1 , wherein the pH of the leaching solution is maintained at a value less than 2.5 during leaching. 
     
     
         11 . The method of  claim 1 , wherein the pH of the leaching solution is maintained within the range of about 1.0 to about 2.0 during leaching. 
     
     
         12 . The method of  claim 1 , wherein the pH of the leaching solution is maintained within the range of 1.0 to 1.5 during leaching. 
     
     
         13 . The method of  claim 1 , wherein the acid is sulfuric acid. 
     
     
         14 . The method of  claim 1 , wherein the acid is nitric acid. 
     
     
         15 . The method of  claim 13 , wherein baking the ore releases SO 2  from the ore. 
     
     
         16 . The method of  claim 15 , further comprising:
 collecting the SO 2  generated by the baking step in a first iteration of the method; and   using the SO 2  to make sulfuric acid which is used in treating the ore with an acid in a second iteration of the method.   
     
     
         17 . The method of  claim 16 , wherein the SO 2  is collected with a scrubber. 
     
     
         18 . The method of  claim 14 , wherein baking the ore releases NO x  from the ore. 
     
     
         19 . The method of  claim 18 , further comprising:
 collecting the NO x  generated by the baking step in a first iteration of the method; and   using the NO x  to make nitric acid which is used in treating the ore with an acid in a second iteration of the method.   
     
     
         20 . The method of  claim 19 , wherein the NO x  is collected with a scrubber. 
     
     
         21 . The method of  claim 1 , wherein leaching nickel from the baked ore results in a solution containing a mixture of nickel and scandium ions. 
     
     
         22 . The method of  claim 1 , further comprising:
 extracting nickel from the leachate by contacting the leachate with an ion exchange resin which is selective to the absorption of nickel, thereby forming a nickel-loaded resin and a raffinate;   separating the raffinate from the resin;   extracting the nickel from the nickel loaded resin by contacting the resin with an acid and forming a soluble nickel salt thereof as an eluate; and   
       recovering nickel from said eluate. 
     
     
         23 . The method of  claim 22 , wherein recovering nickel from said eluate comprises salting out the nickel by crystallization of nickel sulfate heptahydrate. 
     
     
         24 . The method of  claim 23 , wherein salting out the nickel includes the addition of concentrated sulfuric acid to the eluate. 
     
     
         25 . The method of  claim 24 , further comprising:
 recycling the crystallization mother liquor with residual acid values back to the acid treatment step of the process.   
     
     
         26 . The method of  claim 22 , wherein the raffinate comprises iron, magnesium and the acid. 
     
     
         27 . The method of  claim 22 , further comprising:
 prior to extracting nickel from the leachate, adjusting the pH of the leachate to a range of about 1 to 3.   
     
     
         28 . The method of  claim 22 , wherein contacting the resin with an acid involves contacting the resin with a mineral acid. 
     
     
         29 . The method of  claim 22 , wherein the nickel-containing ore is a lateritic ore containing at least about 3% magnesium, at least about 10% iron and at least about 0.5% nickel. 
     
     
         30 . The method of  claim 22 , wherein the nickel-containing ore has a particle size less than about one inch. 
     
     
         31 . The method of  claim 22 , wherein the pH of said leachate is adjusted by adding a neutralizing agent to said leachate; and wherein any residue remaining in said pH-adjusted leachate is removed prior to the extraction of nickel therefrom. 
     
     
         32 . The method of  claim 22 , wherein the absorbed nickel is extracted from the nickel-loaded resin with a solution of HCl to form a nickel chloride solution, wherein said nickel chloride solution is subjected to pryo-hydrolysis to form a nickel oxide. 
     
     
         33 . The method in  claim 32 , wherein said nickel oxide is further processed to metallic nickel. 
     
     
         34 . The method of  claim 22 , wherein contacting said leachate with said ion exchange resin provides a raffinate containing iron and magnesium, wherein said nickel is separated from said resin with a mineral acid to form a soluble nickel salt as an eluate thereof, and wherein substantially pure nickel is recovered from said eluate. 
     
     
         35 . The method of  claim 22 , wherein said leachate contains Ni, Fe and Mg, wherein said leachate is passed through a bed of the ion exchange resin to produce a raffinate deficient in nickel and containing Fe and Mg, and wherein nickel is extracted from said the nickel loaded resin with HCl to provide an eluate of nickel chloride. 
     
     
         36 . The method of  claim 35 , wherein said eluate is subjected to pyrohydrolysis to form NiO, and wherein said raffinate is subjected to pyro-hydrolysis to form MgO/FeOH 3  for recycle. 
     
     
         37 . The method of  claim 36 , wherein MgO/FeOH 3  is recycled into the leaching system as a neutralizing agent. 
     
     
         38 . The method of  claim 36 , wherein the MgO/FeOH 3  is also used to produce HCl for recycle into the leaching system. 
     
     
         39 . The method of  claim 38 , wherein the HCl produced is further used to recycle to said ion exchange resin as a stripping agent. 
     
     
         40 . The method of  claim 22 , wherein said leachate contains iron and magnesium, and further comprising:
 contacting said leachate with the resin so as to form a nickel-loaded resin and a raffinate which is deficient in nickel and which comprises Fe and Mg;   passing mineral acid through a bed of the nickel loaded resin to extract the nickel as a soluble salt of the mineral acid as an eluate thereof; and   
       recovering said nickel from said eluate. 
     
     
         41 . The method of  claim 40 , wherein the resin is a bis(2-picolyl)amine resin. 
     
     
         42 . The method of  claim 40 , wherein said mineral acid is H 2 SO 4 , wherein said nickel-containing eluate is a nickel sulfate solution, and wherein said nickel sulfate solution is subjected to electrowinning to form substantially pure electro-nickel. 
     
     
         43 . A method for extracting nickel values from nickel-containing ores, the method comprising:
 providing an ore which contains nickel;   treating the ore with an acid;   baking the ore, thus generating gaseous effluents;   recycling the gaseous effluents to reconstitute the acid; and   
       using the reconstituted acid in a second iteration of the method. 
     
     
         44 .- 84 . (canceled) 
     
     
         85 . A method for extracting nickel values from ores that contain both nickel and scandium, the method comprising:
 treating the ore with an acid, thereby producing an acid treated ore;   baking the acid treated ore, thereby producing a baked ore;   leaching nickel and scandium from the baked ore to form a leachate; and   
       extracting both the nickel and scandium values from the leachate. 
     
     
         86 .- 131 . (canceled)