Electrified liquid-liquid extraction system for selective extraction of precious metal species

Patent metadata

Field	Value
Publication number	US-2024425947-A1
Application number	US-202418739942-A
Country	US
Kind code	A1
Filing date	Jun 11, 2024
Priority date	Jun 13, 2023
Publication date	Dec 26, 2024
Grant date	—

Abstract

Electrified liquid-liquid extraction systems including an alkyl-substituted ferrocene compound as an organic adsorbent are provided herein. Methods of recovering a metal from a leach solution are further provided.

First claim

1 . An electrified liquid-liquid extraction system, comprising:
an organic adsorbent loop, through which flows a solution of an alkyl-substituted ferrocene compound in an organic solvent, the organic adsorbent loop comprising, in a direction of flow of the solution, an oxidation solvent extraction column, a leach solvent extraction column, and a reduction solvent extraction column; an aqueous oxidant loop, through which flows an aqueous oxidant solution comprising an oxidizing agent, the aqueous oxidant loop comprising, in a direction of flow of the aqueous solution of the oxidizing agent, the oxidation solvent extraction column and an anode of a flow cell; an aqueous reductant loop, through which flows an aqueous reductant solution comprising a reducing agent, the aqueous reductant loop comprising, in a direction of flow of the aqueous solution of the reducing agent, the reduction solvent extraction column and a cathode of the flow cell; a leach stream loop, through which flows a leach solution, the leach stream loop comprising the leach solvent extraction column; and the flow cell, comprising an ion exchange membrane between the cathode and the anode.

2 . The system of claim 1 , wherein the alkyl-substituted ferrocene compound is a compound of formula (I):

wherein each of R 1 , R 2 , R 3 , R 4 , R 5 , R 1 ′, R 2 ′, R 3 ′, R 4 ′, and R 5 ′ is independently hydrogen or (C 1 -C 30 )alkyl; and
wherein at least one of R 1 , R 2 , R 3 , R 4 , R 5 , R 1 ′, R 2 ′, R 3 ′, R 4 ′, and R 5 ′ is (C 1 -C 30 )alkyl.

3 . The system of claim 1 , wherein the alkyl-substituted ferrocene compound is selected from the group consisting of: 1,1′-diethylferrocene, octylferrocene, 1,1′-didodecylferrocene, and any combination thereof.

4 . The system of claim 1 , wherein the organic solvent is dibromomethane, dichloromethane, or a combination thereof.

5 . The system of claim 1 , wherein the oxidizing agent is selected from the group consisting of NOBF 4 , Na 2 CrO 4 , Na 3 VO 4 , FeCl 3 , and NaI 3 .

6 . The system of claim 1 , wherein the reducing agent is selected from the group consisting of Na 2 S 2 O 5 , NaS 2 O 3 , ascorbic acid, and Na 4 Fe(CN) 6 .

7 . The system of claim 1 , wherein the leach solution comprises an ionic species comprising gold, platinum, iridium, palladium, silver, rhodium, and any combination thereof.

8 . The system of claim 1 , wherein the leach solution comprises a gold anionic species at a molarity of less than or equal to 0.2 mM.

9 . A method of recovering a metal from a leach solution, comprising:
cycling a solution of an alkyl-substituted ferrocene compound in an organic solvent sequentially through an oxidation solvent extraction column, a leach solvent extraction column, and a reduction solvent extraction column in an organic adsorbent loop; oxidizing the alkyl-substituted ferrocene compound in the oxidation solvent extraction column to provide an oxidized alkyl-substituted ferrocene compound; adsorbing an anionic species of the metal from the leach solution to the oxidized alkyl-substituted ferrocene compound in the leach solvent extraction column to provide a complex of the anionic species and the oxidized alkyl-substituted ferrocene compound; and reducing the oxidized alkyl-substituted ferrocene compound to provide the alkyl-substituted ferrocene compound in the reduction solvent extraction column, the anionic species transferred to an aqueous reductant solution in the reduction solvent extraction column.

10 . The method of claim 9 , wherein the cycling is performed continuously.

11 . The method of claim 9 , wherein the alkyl-substituted ferrocene compound is a compound of formula (I):

wherein each of R 1 , R 2 , R 3 , R 4 , R 5 , R 1 ′, R 2 ′, R 3 ′, R 4 ′, and R 5 ′ is independently hydrogen or (C 1 -C 30 )alkyl; and
wherein at least one of R 1 , R 2 , R 3 , R 4 , R 5 , R 1 ′, R 2 ′, R 3 ′, R 4 ,′ and R 5 ′ is (C 1 -C 30 )alkyl.

12 . The method of claim 9 , wherein the alkyl-substituted ferrocene compound is selected from the group consisting of: 1,1′-diethylferrocene, octylferrocene, 1,1′-didodecylferrocene, and any combination thereof.

13 . The method of claim 9 , wherein the organic solvent comprises a halogen.

14 . The method of claim 9 , wherein the oxidizing comprises cycling an aqueous oxidant solution comprising an oxidizing agent through an aqueous oxidant loop, the aqueous oxidant loop comprising the oxidation solvent extraction column.

15 . The method of claim 9 , wherein the oxidizing agent is selected from the group consisting of NOBF 4 , Na 2 CrO 4 , Na 3 VO 4 , FeCl 3 , and NaI 3 .

16 . The method of claim 9 , wherein the adsorbing comprises cycling the leach solution through a leach stream loop comprising the leach solvent extraction column.

17 . The method of claim 9 , further comprising regenerating the oxidizing agent at an anode of a flow cell, the aqueous oxidant loop comprising the anode downstream of the oxidation solvent extraction column.

18 . The method of claim 9 , further comprising regenerating the reducing agent at a cathode of a flow cell, the aqueous reductant loop comprising the cathode downstream of the reduction solvent extraction column.

19 . The method of claim 9 , further comprising preparing the leach solution from electronic waste.

20 . The method of claim 9 , wherein the leach solution is prepared by heap leaching or dump leaching.

Assignees

• Univ Illinois

Inventors

• Su Xiao
• Cotty Stephen
• Faniyan Aderiyike
• Elbert Johannes

Classifications

• C22B11/04

  by wet processes (extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26) · CPC title

• C22B11/046

  from manufactured products, e.g. from printed circuit boards, from photographic films, paper or baths · CPC title

• C22B3/26 Primary

  by liquid-liquid extraction using organic compounds · CPC title

• C22B3/42

  by ion-exchange extraction · CPC title

• C22B3/02

  Apparatus therefor · CPC title