Systems and methods for improved metal recovery using ammonia leaching

1. A method comprising:

leaching a slurry comprising a copper bearing material and an ammonia leach medium;

adding to the slurry copper powder comprising greater than ninety percent copper;

separating the slurry into a pregnant leach solution and solids; and

performing a solvent extraction on the pregnant leach solution to produce a loaded aqueous stream; wherein the leaching is performed in an anoxic environment.

2. The method of claim 1 , wherein the copper powder comprises at least one of dendritic copper powder and molten sprayed copper powder.

3. The method of claim 1 , further comprising:

producing a cobalt precipitate from a raffinate produced by solvent extraction; and

subjecting the cobalt precipitate to a metal recovery process.

4. The method of claim 3 , further comprising adding ammonium hydrosulfide to the raffinate produced by solvent extraction.

5. The process of claim 4 , subjecting the loaded aqueous stream to electrowinning.

6. The method of claim 1 , further comprising wet grinding the copper bearing material prior to the leaching.

7. The method of claim 1 , further comprising adding sulfur dioxide gas to the slurry.

8. The method of claim 7 , further comprising adding air to the slurry.

9. The method of claim 1 , subjecting the loaded aqueous stream to electrowinning to yield copper metal at a cathode.

10. The method of claim 1 , wherein the solvent extraction comprises subjecting the pregnant leach solution to a copper-specific extracting reagent.

11. The process of claim 1 , wherein the solvent extraction comprises scrubbing an organic phase with a weak acid.

12. The process of claim 11 , wherein the weak acid is carbonic acid.

13. The process of claim 12 , wherein the carbonic acid is added through dissolving carbon dioxide in water.