# US 4,382,845 A · Selective electrowinning of palladium

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- Number: US 4,382,845 A
- Document ID: US4382845A
- Status: Granted
- Kind: A
- Application number: 06/291,607
- Filed: 1981-08-10
- Granted: 1983-05-10
- Earliest claimed: 1981-08-10
- Assignees: Chevron Research Company
- Inventors: Gale L. Hubred
- Web page: https://patentgrep.com/patent/US4382845A

## CPC

- C25C 1/20: of noble metals
- C25C: PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR

## Abstract

A process for electrowinning palladium values from an aqueous solution that contains platinum and palladium.

## Claims

### Claim 1

A process for selectively removing palladium from a mixture containing more palladium by weight than platinum comprising:
forming a first solution in a leach tank, which contains at least 1 M hydrochloric acid, and said palladium and platinum;
contacting said first solution with a cathode, said cathode in a compartment in a cell separated from an anode by a cation permeable membrane, said anode in contact with a second solution consisting of at least 0.5 molar hydrochloric acid; and
passing electric current across said anode and cathode until the concentration of palladium and platinum is substantially equal in said first solution, when said concentrations are measured in grams of metal per liter.

### Claim 2 (depends on 1)

The process of claim 1 further including monitoring the concentrations of metals in the solutions by atomic absorption spectroscopy.

### Claim 3 (depends on 1)

The process of claim 1 wherein the voltage of the electric energy does not exceed 5 volts.

### Claim 4 (depends on 1)

The process of claim 1 further comprising recycling the solution from said cell to said leach tank.