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

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)