Platinum group metals recovery

Patent metadata

Field	Value
Publication number	US-11225702-B2
Application number	US-201916353831-A
Country	US
Kind code	B2
Filing date	Mar 14, 2019
Priority date	Mar 15, 2018
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

The disclosed methods are utilized for recovering a high percent of platinum group metals from spent catalytic converters. The methods use an aqua regia bath and ultrasonic agitation to liberate the metals from the carrier material of the washcoat, while leaving the metal supporting structure largely intact.

First claim

What is claimed is:

1. A method for recovering platinum group metal (PGM) from a washcoat deposited on a metal supporting structure of a catalytic converter, wherein the washcoat contains PGM and a carrier material, the method comprising the steps of:
contacting the washcoat deposited on the metal supporting structure with aqua regia during ultrasonic agitation for a period of time sufficient to dissolve PGM into the aqua regia to produce a recovery mixture which contains less than 50% of the carrier material from the washcoat, and wherein at least a portion of the metal supporting structure remains after this contacting step; and
recovering at least a portion of the PGM from the recovery mixture.

2. The method of claim 1 , wherein after the period of time, the recovery mixture contains less than 30% of the carrier material.

3. The method of claim 1 , wherein after the period of time, the recovery mixture contains less than 20% of the carrier material.

4. The method of claim 1 , wherein after the period of time, the recovery mixture contains less than 10% of the carrier material.

5. The method of claim 1 , wherein at least 80% of the PGM in the washcoat are recovered in the step of recovering at least a portion of the PGM from the recovery mixture.

6. The method of claim 1 , wherein at least 90% of the PGM in the washcoat are recovered in the step of recovering at least a portion of the PGM from the recovery mixture.

7. The method of claim 1 , wherein the contacting is carried out at a temperature below 100° C.

8. The method of claim 1 , wherein the PGM includes at least one metal selected from the group consisting of platinum, rhodium and palladium, and wherein at least 95% of the at least one metal is recovered in the step of recovering at least a portion of the PGM from the recovery mixture.

9. The method of claim 1 , wherein the PGM includes at least one metal selected from the group consisting of platinum, rhodium and palladium, and wherein at least 98% of the at least one metal is recovered in the step of recovering at least a portion of the PGM from the recovery mixture.

10. The method of claim 8 , wherein after the period of time, the recovery mixture contains less than 20% of the carrier material.

11. The method of claim 1 , wherein the aqua regia comprises about a 3 to 1 ratio or less of HCl to HNO 2 .

12. The method of claim 1 , wherein the step of recovering at least a portion of the PGM comprises:
separating the metal supporting structure from the recovery mixture;
removing carrier material solids from the recovery mixture; and
heating the recovery mixture from which carrier material solids have been removed so as to precipitate PGM.

13. The method of claim 11 , further comprising:
rinsing the thus separated metal supporting structure with water during ultrasonic agitation to produce a wash mixture; and
adding the wash mixture to the recovery mixture prior to recovering the at least a portion of the PGM from the recovery mixture.

14. The method of claim 13 , wherein after the period of time, the recovery mixture contains less than 20% of the carrier material, and wherein the PGM includes at least one metal selected from the group consisting of platinum, rhodium and palladium, and wherein at least 95% of the at least one metal is recovered in the step of recovering at least a portion of the PGM from the recovery mixture.

15. The method of claim 1 , wherein the aqua regia comprises about a 3 to 1 ratio of HCl to HNO 2 .

Assignees

• Univ Oklahoma State

Inventors

• Sarin Pankaj
• Nichols David K

Classifications

• C22B11/048 Primary

  from spent catalysts · CPC title

• B01J38/60

  using acids · CPC title

• B01J23/96

  of catalysts comprising metals, oxides or hydroxides of the noble metals · CPC title

• Y02P10/20

  Recycling · CPC title