Integrated ammoniacal solvent extraction and hydrogen reduction of nickel
A process is provided for the recovery of a metallic nickel product in a solvent extraction process which includes the steps of forming a nickel ammine complex by stripping nickel from a nickel loaded organic phase with a high strength ammonia solution and then reducing the nickel ammine complex with hydrogen from the high strength ammonia solution to produce a metallic nickel product. By virtue of the present process, a reductive precipitation of nickel by hydrogen is obtained so as to recover a metallic nickel product, and the process is advantageous in that it will allow for commercial processes wherein nickel may be recovered by hydrogen reduction based on high strength ammonia solutions.
1. An integrated process for the recovery of a metallic nickel product from a solvent extraction process comprising:
(a) forming a nickel ammine complex substantially as a hexammine complex, by stripping nickel from a nickel loaded organic phase with a high strength ammonia solution selected from the group consisting of an ammoniacal ammonium carbonate solution and a high strength ammoniacal ammonium sulfate solution, wherein following step (a), the molar ratio of ammonia to nickel in the high strength ammoniacal ammonium sulfate solution is greater than 6:1, or the molar ratio of ammonia to nickel in the high strength ammoniacal ammonium carbonate solution is greater than 8:1; and
(b) reducing the nickel ammine complex from the high strength ammonia solution with hydrogen to produce a metallic nickel product.
2. The integrated process according to claim 1 , wherein the nickel ammine complex is a nickel ammine carbonate complex, and the high strength ammonia solution is a high strength ammoniacal ammonium carbonate solution.
3. The integrated process according to claim 1 , wherein the nickel ammine complex is a nickel ammine sulfate complex, and the high strength ammonia solution is a high strength ammoniacal ammonium sulfate solution.
4. The integrated process according to claim 1 , wherein the organic phase is formed in the solvent extraction process, whereby an organic reagent is used to extract nickel ions from an ammoniacal ammonium carbonate liquor to form the organic phase.
5. The integrated process according to claim 4 , wherein the organic reagent is selected from 2-hydroxy-5-t-nonyl-acetophenoneoxime, 2-hydroxy-5-t-nonyl-salicylaldoxime, and alkyl, aryl and halide substituted beta diketone types.
6. The integrated process according to claim 5 , wherein the organic reagent is a 2-hydroxy-5-t-nonyl-acetophenoneoxime modified by an alcohol in an aliphatic or aromatic kerosene type carrier or a combination of both.
7. The integrated process according to claim 4 , wherein the nickel exists as a nickel II ion in the ammoniacal ammonium carbonate liquor prior to being extracted with the organic reagent.
8. The integrated process according to claim 2 , wherein the high strength ammoniacal ammonium carbonate solution used to strip the organic phase has an ammonia concentration of about 210 to 300 g/L and a carbon dioxide concentration of about 50 to 150 g/L.
9. The integrated process according to claim 8 , wherein the high strength ammoniacal ammonium carbonate solution has an ammonia concentration of about 260 g/L.
10. The integrated process according to claim 9 , wherein the high strength ammoniacal ammonium carbonate solution after the nickel has been stripped from the organic phase contains 50 to 90 g/L nickel as the nickel carbonate hexammine complex.
11. The integrated process according to claim 3 , wherein the high strength ammoniacal ammonium sulfate solution used to strip the organic phase has an ammonia concentration of about 160 to 300 g/L and sulfate concentration of about 50 to 180 g/L.
12. The integrated process according to claim 11 , wherein the high strength ammoniacal ammonium sulfate solution has an ammonia concentration of about 160-200 g/L and a sulfate concentration of about 70 to 160 g/L.
13. The integrated process according to claim 12 , wherein the high strength ammoniacal ammonium sulfate solution, after the nickel has been stripped from the organic phase, contains 30 to 60 g/L nickel as the nickel sulphate sulfate hexammine complex.
14. The integrated process according to claim 2 , wherein the reaction product of the hydrogen reduction of the nickel hexammine carbonate complex is metallic nickel, ammonium carbonate and ammonia.
15. The integrated process according to claim 3 , wherein the reaction product of the nickel hexammine sulfate complex is a metallic nickel, ammonium sulfate and ammonia.
16. The integrated process of claim 1 , wherein (b) reducing the nickel ammine complex comprises reducing the nickel ammine complex directly from the high strength ammonia solution with hydrogen to produce the metallic nickel product.
17. The integrated process according to claim 9 , wherein the high strength ammoniacal ammonium carbonate solution after the nickel has been stripped from the organic phase contains 50 to 90 g/L nickel substantially as the nickel carbonate hexammine complex.
18. The integrated process according to claim 12 , wherein the high strength ammoniacal ammonium sulfate solution, after the nickel has been stripped from the organic phase, contains 30 to 60 g/L nickel substantially as the nickel sulfate hexammine complex.
19. An integrated process for the recovery of a metallic nickel product from a solvent extraction process consisting essentially of:
(a) forming a nickel ammine complex substantially as a hexammine complex, by stripping nickel from a nickel loaded organic phase with a high strength ammonia solution selected from the group consisting of an ammoniacal ammonium carbonate solution and a high strength ammoniacal ammonium sulfate solution, wherein following step (a), the molar ratio of ammonia to nickel in the high strength ammoniacal ammonium sulfate solution is greater than 6:1, or the molar ratio of ammonia to nickel in the high strength ammoniacal ammonium carbonate solution is greater than 8:1; and
(b) reducing the nickel ammine complex from the high strength ammonia solution with hydrogen to produce a metallic nickel product.
20. An integrated process for the recovery of a metallic nickel product from a solvent extraction process consisting of:
(a) forming a nickel ammine complex substantially as a hexammine complex, by stripping nickel from a nickel loaded organic phase with a high strength ammonia solution selected from the group consisting of an ammoniacal ammonium carbonate solution and a high strength ammoniacal ammonium sulfate solution, wherein following step (a), the molar ratio of ammonia to nickel in the high strength ammoniacal ammonium sulfate solution is greater than 6:1, or the molar ratio of ammonia to nickel in the high strength ammoniacal ammonium carbonate solution is greater than 8:1; and
(b) reducing the nickel ammine complex from the high strength ammonia solution with hydrogen to produce a metallic nickel product.