Systems and methods for improved metal recovery using ammonia leaching

Patent metadata

Field	Value
Publication number	US-2018298505-A1
Application number	US-201816011037-A
Country	US
Kind code	A1
Filing date	Jun 18, 2018
Priority date	Mar 14, 2013
Publication date	Oct 18, 2018
Grant date	—

Abstract

Systems and methods for basic leaching are provided. In various embodiments, a method is provided comprising leaching a slurry comprising a copper bearing material and an ammonia leach medium, adding copper powder to the slurry, separating the slurry into a pregnant leach solution and solids, and performing a solvent extraction on the pregnant leach solution to produce an loaded aqueous stream.

First claim

1 . (canceled)

2 . A method comprising:
leaching a slurry comprising a metal bearing material and an ammonia leach medium, wherein the metal bearing material comprises copper and cobalt; adding a reducing agent to the slurry, wherein the reducing agent comprises a copper powder, and wherein the reducing agent is added to the slurry such that a stoichiometric ratio of copper to cobalt is greater than 0.5; and 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.

3 . The method of claim 2 , wherein the stoichiometric ratio of copper to cobalt is between about 4 and about 12.

4 . The method of claim 3 , wherein the stoichiometric ratio of copper to cobalt is about 8.

5 . The method of claim 2 , further comprising: producing a cobalt precipitate from a raffinate produced by the solvent extraction; and subjecting the cobalt precipitate to a metal recovery process.

6 . The method of claim 5 , further comprising adding ammonium hydrosulfide to the raffinate produced by the solvent extraction.

7 . The method of claim 2 , subjecting the loaded aqueous stream to electrowinning.

8 . The method of claim 2 , further comprising wet grinding the metal bearing material prior to the leaching.

9 . The method of claim 2 , further comprising adding sulfur dioxide gas to the slurry.

10 . The method of claim 9 , further comprising adding air to the slurry.

11 . The method of claim 2 , wherein the solvent extraction comprises subjecting the pregnant leach solution to a copper specific extracting reagent.

12 . The method of claim 2 , wherein the solvent extraction comprises scrubbing an organic phase with a weak acid.

13 . The method of claim 12 , wherein the weak acid is carbonic acid.

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

Assignees

• Freeport Minerals Corp

Inventors

• Robertson Joanna M
• Bolles Thomas R
• Gertenbach Dennis D

Classifications

• C22B15/0093

  by gases, e.g. hydrogen or hydrogen sulfide · CPC title

• C22B3/14

  containing ammonia or ammonium salts · CPC title

• C22B23/0446

  with an ammoniacal liquor or with a hydroxide of an alkali or alkaline-earth metal · CPC title

• C22B15/0008 Primary

  by wet processes (by flotation B03D) · CPC title

• C25C1/12 Primary

  of copper · CPC title