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 a reducing agent to the slurry, wherein the reducing agent comprises at least one of dendritic copper powder, molten sprayed copper powder, and metallic copper powder having a neutral oxidation state;

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.

2. 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.

3. The method of claim 2 , further comprising adding ammonium hydrosulfide to the raffinate produced by solvent extraction.

4. The process of claim 3 , subjecting the loaded aqueous stream to electrowinning.

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

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

7. The method of claim 6 , further comprising adding air to the slurry.

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

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

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

11. The process of claim 10 , wherein the weak acid is carbonic acid.

12. The process of claim 11 , wherein the carbonic acid is added through dissolving carbon dioxide in water.