Extraction of selected platinum-group metals from supported catalyst

Patent metadata

Field	Value
Publication number	US-2019161824-A1
Application number	US-201816199568-A
Country	US
Kind code	A1
Filing date	Nov 26, 2018
Priority date	Nov 27, 2017
Publication date	May 30, 2019
Grant date	—

Abstract

Disclosed herein is a method for extracting precious metals from supported catalysts. The precious metal in one embodiment is rhodium. The supported catalyst may be from equipment, such as a used catalytic converter. The method is carried out at low temperature, and does not require harsh conditions, such as the use of a strong acid. The method involves contacting the catalytic material with a polar molecule and a reactive gas.

First claim

What is claimed is:

1 . A method of extracting a selected platinum group metal from a composite, the method comprising:
immersing a composite comprising the selected platinum group metal in a liquid comprising a polar molecule; and while the composite is immersed, exposing the composite to a reactive gas to extract the selected platinum group metal therefrom.

2 . The method of claim 1 , wherein the composite is a supported catalyst comprising a particulate catalyst bonded to a support, the particulate catalyst comprising the selected platinum group metal and the support comprising a support material.

3 . The method of claim 1 , wherein the selected platinum group metal comprises one of rhodium, rhenium, ruthenium, palladium, or platinum.

4 . The method of claim 1 , wherein the selected platinum group metal comprises rhodium.

5 . The method of claim 1 , wherein the polar molecule is an organic solvent.

6 . The method of claim 1 , wherein the reactive gas comprises one of carbon monoxide or nitric oxide.

7 . The method of claim 1 , wherein the exposure of the composite to the reactive gas occurs at a pressure between 1 bar and 25 bar.

8 . The method of claim 1 , wherein the exposure to the reactive gas occurs at a temperature below 80 degrees Celsius.

9 . The method of claim 1 , wherein the reactive gas is generated by reaction of a liquid precursor in contact with the composite.

10 . The method of claim 9 , wherein the liquid precursor comprises one of formic acid, formaldehyde, and chloroform.

11 . The method of claim 1 , wherein the polar molecule comprises at least one of acetonitrile, ethyldimethylamine, dimethylformamide, or trimethylamine.

12 . The method of claim 1 , wherein at least 90% of the selected platinum group metal is extracted from the composite after 24 hours.

13 . The method of claim 1 , further comprising pretreating the composite at an elevated temperature and under a flow of pretreatment gas.

14 . The method of claim 1 , wherein the selected platinum group metal is in oxidized form in the composite.

15 . The method of claim 1 , wherein the selected platinum group metal is in reduced form in the composite.

16 . A method of extracting a quantity of rhodium from a composite, the method comprising:
immersing the composite into an aqueous liquid comprising an organic solvent; and while the composite is immersed, exposing the composite to one of nitric oxide or carbon monoxide at a temperature below 80 degrees Celsius to extract the quantity of rhodium.

17 . The method claim 16 , wherein extraction is conducted at a pressure between 1 bar and 25 bar and at a temperature between 25 degrees Celsius and 70 degrees Celsius.

18 . The method of claim 16 , wherein the organic solvent comprises at least one of acetonitrile, ethyldimethylamine, dimethylformamide, or trimethylamine.

19 . The method of claim 16 , wherein at least 90% of the rhodium is extracted after 24 hours.

20 . A method of separating rhodium from a supported catalyst, the method comprising:
immersing a supported catalyst comprising rhodium and a catalytically inert support material into an aqueous liquid comprising at least one of acetonitrile, ethyldimethylamine, dimethylformamide, or trimethylamine; and while the supported catalyst is immersed, exposing the supported catalyst to one of nitric oxide and carbon monoxide at a temperature below 80 degrees Celsius and at a pressure between 1 bar and 25 bar to extract the rhodium, such that at least 90% of the rhodium is extracted after 24 hours.

Assignees

• Univ Illinois

Inventors

• Ibrahim Malek Y S
• Denmark Scott E

Classifications

• B01D53/94

  by catalytic processes · CPC title

• C22B7/009

  General processes for recovering metals or metallic compounds from spent catalysts (for recovering specific metals C22B11/00 - C22B61/00) · CPC title

• B01D2255/1025

  Rhodium · CPC title

• C22B11/04 Primary

  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

• Y02P10/20

  Recycling · CPC title