Electrochemical system and method for selective recovery of gold from electronic waste and mining streams

Patent metadata

Field	Value
Publication number	US-2024271303-A1
Application number	US-202418436586-A
Country	US
Kind code	A1
Filing date	Feb 8, 2024
Priority date	Feb 9, 2023
Publication date	Aug 15, 2024
Grant date	—

Abstract

An electrochemical system for selective recovery of gold from electronic waste and mining streams includes a vessel configured for flow of fluid therethrough, a working electrode positioned in the vessel, where the working electrode comprises a redox-active metallopolymer, and a counter electrode spaced apart from the working electrode in the vessel. An electrochemical method for selective gold recovery includes selectively electrochemically adsorbing gold complexes from a leach solution onto a redox-active metallopolymer, and electrochemically releasing the gold complexes from the redox-active metallopolymer into a collection fluid.

First claim

1 . An electrochemical method for selective recovery of gold from electronic waste and mining streams, the electrochemical method comprising:
selectively electrochemically adsorbing gold complexes from a leach solution onto a redox-active metallopolymer; and electrochemically releasing the gold complexes from the redox-active metallopolymer into a collection fluid.

2 . The electrochemical method of claim 1 , wherein the gold complexes comprise anionic gold species.

3 . The electrochemical method of claim 1 , wherein the leach solution is obtained from electronic waste or mining streams.

4 . The electrochemical method of claim 1 , wherein the leach solution includes other metal complexes in addition to the gold complexes.

5 . The electrochemical method of claim 1 , wherein the redox-active metallopolymer comprises polyvinylferrocene (PVF), polyferrocenyl silane (PFS), poly(3-ferrocenylpropyl methacrylamide (PFPMAm), poly(2-((1-ferrocenylethyl)(methyl)amino)ethyl methacrylate) (PFEMA), and/or poly(2-(methacryloyloxy)ethyl ferrocenecarboxylate) (PFCMA).

6 . The electrochemical method of claim 1 , wherein the leach solution includes a dilute concentration of the gold complexes, the dilute concentration being in a range from 1-10 ppm and/or from 0.004 mM to 5 mM.

7 . The electrochemical method of claim 1 , further comprising:
after releasing the gold complexes into the collection fluid, electrodepositing metallic gold onto a conductive substrate from the gold complexes in the collection fluid.

8 . The electrochemical method of claim 1 being carried out in a vessel configured for fluid flow, the vessel containing a working electrode comprising the redox-active metallopolymer, and further comprising a counter electrode in the vessel spaced apart from the working electrode.

9 . The electrochemical method of claim 8 , wherein the counter electrode also includes the redox-active metallopolymer,
wherein the working electrode is a first electrode and wherein the counter electrode is a second electrode, and further comprising a cation exchange membrane (CEM) in the vessel between the first and second electrodes, the cation exchange membrane separating a first flow channel containing the first electrode from a second flow channel containing the second electrode.

10 . The electrochemical method of claim 9 , further comprising:
applying an oxidizing potential to the first electrode and applying a reducing potential to the second electrode, and during the application of the oxidizing and reducing potentials, flowing a leach solution through the first flow channel and flowing a collection fluid through the second flow channel, whereby gold complexes from the leach solution are adsorbed onto the redox-active metallopolymer of the first electrode and gold complexes adsorbed onto the redox-active metallopolymer of the second electrode are released into the collection fluid.

11 . The electrochemical method of claim 9 , further comprising:
applying a reducing potential to the first electrode and applying an oxidizing potential to the second electrode, and during the application of the reducing and oxidizing potentials, flowing a collection fluid through the first flow channel and flowing a leach solution through the second flow channel, whereby gold complexes from the leach solution are adsorbed onto the redox-active metallopolymer of the second electrode and gold complexes adsorbed onto the redox-active metallopolymer of the first electrode are released into the collection fluid.

12 . The method of claim 1 , wherein the leach solution is recirculated for use in multiple cycles of electrochemical adsorption, and/or
wherein the collection fluid is recirculated for use in multiple cycles of electrochemical release.

13 . The method of claim 1 , wherein the leach solution is continuously supplied as fresh leach solution for electrochemical adsorption and then is removed after the electrochemical adsorption as spent leach solution or tailings.

14 . An electrochemical system for selective recovery of gold from electronic waste and mining streams, the electrochemical system comprising:
a vessel configured for flow of fluid therethrough; a working electrode positioned in the vessel, the working electrode comprising a redox-active metallopolymer; and a counter electrode spaced apart from the working electrode in the vessel.

15 . The electrochemical system of claim 14 , wherein the counter electrode also comprises the redox-active metallopolymer, the working electrode being a first electrode and the counter electrode being a second electrode, and
further comprising a cation exchange membrane in the vessel between the first and second electrodes, the cation exchange membrane separating a first flow channel containing the first electrode from a second flow channel containing the second electrode.

16 . The electrochemical system of claim 14 , further comprising an electrowinning cell having an inlet in fluid communication with an outlet of the vessel.

17 . The electrochemical system of claim 14 , further comprising a source of collection fluid in fluid communication with an inlet and an outlet of the vessel, thereby defining a closed loop for recirculation of the collection fluid through the electrochemical system.

18 . The electrochemical system of claim 14 , further comprising a source of leach solution in fluid communication with an inlet and an outlet of the vessel, thereby defining a closed loop for recirculation of the leach solution through the electrochemical system.

19 . The electrochemical system of claim 14 , wherein the redox-active metallopolymer comprises polyvinylferrocene (PVF), polyferrocenyl silane (PFS), poly(3-ferrocenylpropyl methacrylamide (PFPMAm), poly(2-((1-ferrocenylethyl)(methyl)amino)ethyl methacrylate) (PFEMA), and/or poly(2-(methacryloyloxy)ethyl ferrocenecarboxylate) (PFCMA).

20 . An electrode for recovery of gold from electronic waste and mining streams, the electrode comprising:
a conductive substrate; and a redox-active metallopolymer on the conductive substrate.

Assignees

• Univ Illinois

Inventors

• Su Xiao
• Cotty Stephen R

Classifications

• C25C7/08

  Separating of deposited metals from the cathode · CPC title

• C25C7/02

  Electrodes (consumable anodes for the refining the metals C25C1/00 - C25C5/00); Connections thereof · CPC title

• C25C1/20 Primary

  of noble metals · CPC title

• C25C7/04 Primary

  Diaphragms; Spacing elements · CPC title