# US 4,391,685 A · Process for electrolytically pickling steel strip material

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- Number: US 4,391,685 A
- Document ID: US4391685A
- Status: Granted
- Kind: A
- Application number: 06/238,430
- Filed: 1981-02-26
- Granted: 1983-07-05
- Earliest claimed: 1981-02-26
- Assignees: Republic Steel Corporation
- Inventors: George A. Shepard; Philip C. Schillawski
- Web page: https://patentgrep.com/patent/US4391685A

## CPC

- C25F 1/06: Iron or steel
- C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR

## Abstract

A method for efficiently and effectively continuously electrolytically pickling a steel strip by subjecting the strip to the action of direct current in an aqueous neutral salt pickling solution wherein the strip to be pickled forms a conductor between the neutral salt pickling solution containing the cell cathode and an anolyte containing the cell anode wherein the anolyte is electrically isolated from the neutral salt pickling solution.

## Claims

### Claim 1

In a process for electrolytically pickling a steel strip material by subjecting the material to the action of direct current in a pickling bath which contains at least one neutral salt, the improvement comprising the steps of passing the direct current through the strip to be pickled as a conductor between a uni-polar neutral salt pickling bath containing a cathode means an an acid anolyte bath containing an anode means, said acid anolyte bath being remote from said pickling bath.

### Claim 2 (depends on 1)

The process of claim 1 wherein anolyte baths are located upstream and downstream of said pickling bath.

### Claim 3 (depends on 2)

The process of claim 2 wherein the neutral salt pickling bath and the anolyte bath have the same anion.

### Claim 4 (depends on 3)

The process of claim 3 wherein the anion is the sulfate ion.

### Claim 5

In a process for electrolytically pickling a steel strip by subjecting it to the action of direct current in a pickling bath which contains at least one neutral salt, the improvement comprising the steps of introducing the direct current into the strip to be pickled by anode means contained in an aqueous sulfuric acid bath, thereafter pickling the strip while anodic in a uni-polar neutral salt pickling bath containing cathode means, and then passing the strip while it is cathodic through another aqueous sulfuric acid bath containing anode means, and sulfuric acid baths being located upstream and downstream from said pickling bath and isolated therefrom.

### Claim 6 (depends on 5)

The process of claim 5 wherein said pickling bath comprises an aqueous solution of sodium sulfate.