# US 5,705,051 A · Electrochemical process

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- Number: US 5,705,051 A
- Document ID: US5705051A
- Status: Granted
- Kind: A
- Application number: 08/632,574
- Filed: 1996-04-15
- Granted: 1998-01-06
- Earliest claimed: 1995-05-04
- Assignees: Dravo Lime Company
- Inventors: Richard J. Coin; Lynne M. Ernes; Andy W. Getsy; Edward M. Halko; Kenneth L. Hardee; Marilyn J. Niksa
- Web page: https://patentgrep.com/patent/US5705051A

## CPC

- C25B 9/19: with diaphragms
- B01D 53/1425: {Regeneration of liquid absorbents}
- B01D 53/326: {in electrochemical cells}
- C25B 11/03: perforated or foraminous
- C25B 11/031: Porous electrodes
- C25B 11/036: Bipolar electrodes
- C25B 15/087: {Recycling of electrolyte to electrochemical cell}
- C25C 7/02: Electrodes (consumable anodes for the refining the metals C25C1/00 - C25C5/00); Connections thereof
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C25C: PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR

## Abstract

An electrode, electrochemical cell, and electrochemical processes are disclosed. The electrode is a porous, multi-layered electrode which can have an element in flexible, strip form wound around a central, usually flat plate core, which core may serve as a current distributor. In any form, each layer can be represented by a very thin, highly flexible metal mesh. This can be a fine, as opposed to a coarse, mesh which has extremely thin strands and small voids. The electrode will have an active coating. For utilizing this electrode, the cell in one form will be a monopolar cell providing upward, parallel electrolyte flow through the porous, multi-layered electrode. A representative cell can have such electrode at least substantially filling an electrode chamber. The cells can be contained in a cell box that will provide the desired flow-through relationship for the electrolyte to the electrode. In cell operation, electrochemical processes which can be carried out include metal ion oxidation or reduction, oxidation of organic substituents, nitrate reduction as well as salt splitting.

## Claims

### Claim 1

An electrolytic process providing metal ion oxidation or reduction by electrochemical reaction, which process comprises:
(a) establishing a counter electrode chamber having a cathode electrode therein;
(b) providing electrolyte to said counter electrode chamber, said electrolyte being free from metal ion for oxidation or reduction;
(c) providing a diaphragm separating said counter electrode chamber from a working electrode chamber;
(d) establishing said working electrode chamber with a porous, flow-through, fiber-free electrode comprising a rigid core member and autogenously springy exterior wrapping member, which rigid core member comprises a valve metal reinforcement, which core member is in integral engagement with an exterior wrapping member of a multitude of expanded valve metal layers from at least one continuous strip of valve metal mesh wound tightly around said core member, which mesh is a thin, highly flexible mesh of extremely thin strands and small voids, the layers being tightly engaged face-to-face contact with one another; and
(e) circulating electrolyte to said working electrode chamber, said electrolyte containing metal ion for oxidation or reduction.

### Claim 2 (depends on 1)

The process of claim 1 wherein there is established a dimensionally stable anode as said counter electrode in an anolyte having a pH below 7.

### Claim 3 (depends on 1)

The process of claim 1 wherein electrolyte circulating through said counter electrode chamber provides heat removal for said cell.

### Claim 4 (depends on 1)

The process of claim 1 wherein there is provided a separator comprising a non-isotropic fibrous mat comprising 5-70 weight percent organic polymer fiber in adherent combination with about 30-95 weight percent of finely divided inorganic particulates.

### Claim 5 (depends on 1)

The process of claim 1 wherein there is circulated to said working electrode chamber an electrolyte containing ferric ion for reduction.

### Claim 6 (depends on 1)

The process of claim 1 wherein said electrolyte flowing through said working electrode chamber flows through said multitude of expanded valve metal layers which provide a specific area for said working electrode in excess of about 1,500 square inches per square foot.