Process for the Recovery of Nickel and/or Cobalt from a Leach Solution

Abstract

A process for the recovery of nickel and/or cobalt from a nickel and/or cobalt containing solution comprising: (i) contacting the nickel and/or cobalt containing solution with metallic particles of at least one metal that is more electronegative than nickel and/or cobalt thereby enabling a cementation process to occur between the nickel and/or cobalt in the solution and the metallic particles to produce a nickel and/or cobalt cementate; and (ii) separating the nickel and/or cobalt cementate from the metallic particles thereby producing a slurry including nickel and/or cobalt cementate.

1 . A process for the recovery of nickel and/or cobalt from a nickel and/or cobalt containing solution comprising:
 (i) contacting the nickel and/or cobalt containing solution with metallic particles of at least one metal that is more electronegative than nickel and/or cobalt thereby enabling a cementation process to occur between the nickel and/or cobalt in the solution and the metallic particles to produce a nickel and/or cobalt cementate; and   (ii) separating the nickel and/or cobalt cementate from the metallic particles thereby producing a slurry including nickel and/or cobalt cementate.   
     
     
         2 . A process according to  claim 1 , wherein the nickel and/or cobalt containing solution is a pregnant leach solution obtained from a leaching process of a nickel and/or cobalt containing laterite ore or sulfide ore, concentrate, matte or intermediate. 
     
     
         3 . A process according to any preceding claim, wherein the metallic particles include aluminium metal. 
     
     
         4 . A process according to any preceding claim, wherein the particle size distribution of the metallic particles is selected to permit only partial cementation of the metallic particles. 
     
     
         5 . A process according to  claim 4 , wherein the cementation process is conducted to produce a cementation product comprising a central core of the metal of the metallic particles and a thin surface layer of nickel and/or cobalt cementate. 
     
     
         6 . A process to according to any preceding claim, wherein the metallic particles have an average particle size of between 0.1 mm and 25 mm. 
     
     
         7 . A process according to  claim 6 , wherein the metallic particles have an average particle size of between 1 mm and 15 mm. 
     
     
         8 . A process according to according to any preceding claim, wherein at least some of the metallic particles are in the form of pellets. 
     
     
         9 . A process according to any preceding claim, wherein the step of contacting the nickel and/or cobalt containing solution with metallic particles is conducted in a fluidised bed of the metallic particles. 
     
     
         10 . A process according to  claim 9 , further including the step of fluidising the fluidised bed of metallic particles using a generally upwardly directed flow of the nickel and/or cobalt containing solution. 
     
     
         11 . A process according to any preceding claim, wherein the step of separating the nickel and/or cobalt cementate from the metallic particles includes separation on basis of size. 
     
     
         12 . A process according to  claim 11 , wherein separation on basis of size includes the step of:
 passing the mixture of nickel and/or cobalt cementate from the metallic particles through a screen, which has a mesh size chosen to substantially pass the nickel and/or cobalt cementate particles, and to substantially retain the cementation reagent particles.   
     
     
         13 . A process according to  claim 11 , wherein separation on basis of size includes the step of:
 fluidising the mixture of particles in a fluidisation chamber and adjusting the fluidisation velocity to cause larger cementation reagent particles to be retained and the smaller nickel and/or cobalt cementate particles to be swept out of the fluidisation chamber.   
     
     
         14 . A process according to any preceding claim, wherein the pH of the nickel and/or cobalt containing solution during the cementation process is maintained in the range from 0 to 4.5. 
     
     
         15 . A process according to  claim 14 , wherein the pH of the nickel and/or cobalt containing solution during the cementation process is maintained in the range of 2 to 3.5. 
     
     
         16 . A process according to  claim 14 , wherein the pH of the nickel and/or cobalt containing solution during is maintained in the range of 3.5 to 10, and aluminium hydroxide or oxide precipitates during the reaction. 
     
     
         17 . A process according to any preceding claim, further including the step of:
 thickening the resulting slurry including a nickel and/or cobalt cementate.   
     
     
         18 . A process according to any preceding claim, further including the step of:
 filtering the resulting slurry including a nickel and/or cobalt cementate.   
     
     
         19 . A process according to any preceding claim, further including the step of:
 magnetically separating the nickel and/or cobalt particles.   
     
     
         20 . A process according to any preceding claim, further including the step of:
 leaching aluminium hydroxide or oxide to remove aluminium hydroxide or oxide from the nickel and/or cobalt particles.   
     
     
         21 . A process according to  claim 20  in which the leaching step uses a leaching lixiviant comprising a sodium hydroxide solution. 
     
     
         22 . A process according to any preceding claims, further including the steps of:
 (i) feeding the nickel and/or cobalt cementate into a direct melting furnace to produce a molten nickel and/or cobalt metal; and   (ii) casting the molten nickel and/or cobalt metal to produce a cast nickel and/or cobalt metal product.   
     
     
         23 . A process according to  claim 22 , further including the step of:
 (i) forming the nickel and/or cobalt cementate into a briquette; and then   (ii) feeding the nickel and/or cobalt cementate into a direct melting furnace.   
     
     
         24 . A process according to  claim 22 , further including the step of:
 (i) forming the nickel and/or cobalt cementate into a briquette; and then   (ii) introducing the briquettes into a container, crucible or furnace which contains a molten alloy substantially comprising iron and nickel and/or cobalt.   
     
     
         25 . A process for the recovery of nickel from a nickel containing ore comprising:
 (a) subjecting a nickel containing ore to a leach process to produce a nickel containing pregnant leach solution;   (b) contacting the nickel containing pregnant leach solution with aluminium metal particles thereby enabling a cementation process to occur between the nickel in the pregnant leach solution and the aluminium metal particles to produce a nickel cementate;   (c) separating the nickel cementate from the aluminium metal particles thereby producing a slurry including nickel cementate;   (d) forming the nickel cementate into a briquette; and   (e) introducing the nickel cementate briquettes into a container, crucible or furnace which contains a molten alloy substantially comprising iron and nickel.   
     
     
         26 . A process for the recovery of nickel and/or cobalt from a nickel and/or cobalt containing solution substantially as herein described in accordance with the accompanying drawings.