Systems and methods of protecting electrolysis cell sidewalls

Patent metadata

Field	Value
Publication number	US-9957627-B2
Application number	US-201514847926-A
Country	US
Kind code	B2
Filing date	Sep 8, 2015
Priority date	Sep 10, 2014
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

Broadly, the present disclosure relates to sidewall features (e.g. inner sidewall or hot face) of an electrolysis cell, which protect the sidewall from the electrolytic bath while the cell is in operation (e.g. producing metal in the electrolytic cell).

First claim

What is claimed is:

1. An electrolysis cell comprising:
an anode;
a cathode in spaced relation from the anode;
a molten electrolyte bath in liquid communication with the anode and the cathode;
a cell body comprising a sidewall and a bottom,
wherein the cell body is configured to retain the molten electrolyte bath;
wherein the sidewall comprises a second sidewall portion overlapping a first sidewall portion and wherein the overlap is from 0% to not greater than 90% of a total height of the cell sidewall;
wherein the sidewall comprises: a polarized sidewall portion, wherein the polarized sidewall portion comprises not greater than 95% of the sidewall and is in liquid communication with the molten electrolyte bath, wherein the sidewall is from 5 mm thick to 500 mm thick, and wherein the polarized sidewall portion comprises: an anodically polarized sidewall, wherein the anodically polarized sidewall is positioned above the bottom of the cell body and adjacent to the bath-vapor interface, such that the anodically polarized sidewall is in communication with the bath-vapor interface.

2. The electrolysis cell of claim 1 , wherein the polarized sidewall portion comprises an anodically polarized sidewall portion and a cathodically polarized sidewall portion.

3. The electrolysis cell of claim 1 , wherein the polarized sidewall portion comprises:
a cathodically polarized sidewall, wherein the cathodically polarized sidewall is positioned below the bath-vapor interface and adjacent to the bottom of the cell body such that the cathodically polarized sidewall is in liquid communication with the bottom of the cell body.

4. The electrolysis cell of claim 1 , wherein the polarized sidewall portion comprises: at least 50% of surface of an inner sidewall.

5. The electrolysis cell of claim 1 , wherein the apparatus includes: a non-polarized sidewall portion, wherein both the polarized sidewall portion and the non-polarized sidewall portion are adjacent to each other and in liquid communication with the molten electrolyte bath.

6. The electrolysis cell of claim 5 , wherein the non-polarized sidewall portion is positioned above the cathodically polarized sidewall and is in communication with the bath-air interface.

7. The electrolysis cell of claim 5 , wherein the non-polarized sidewall portion is selected from the group consisting of:
a thermal conductor; a stable material; a frozen ledge device, and combinations thereof.

8. The electrolysis cell of claim 5 , wherein the non-polarized sidewall is configured to extend from the cell bottom to a height above a metal-to-bath interface, further wherein the non-polarized sidewall portion is configured adjacent to and in communication with the polarized sidewall portion.

9. An electrolysis cell comprising:
a cell body having a bottom and at least one sidewall, wherein the cell body is configured to retain a molten electrolyte bath, wherein the sidewall comprises:
a first sidewall portion, configured to fit onto a thermal insulation package of the sidewall and retain the electrolyte, the first sidewall portion comprising an anodically polarized sidewall portion, wherein the anodically polarized sidewall is positioned above the bottom of the cell body and adjacent to the bath-vapor interface, such that the anodically polarized sidewall is in communication with the bath-vapor interface;
a second sidewall portion configured to extend up from the bottom of the cell body, wherein the second sidewall portion overlapping a first sidewall portion and wherein the overlap is from 0% to not greater than 90% of a total height of the cell sidewall,
wherein the second sidewall portion is longitudinally spaced from the first sidewall portion, such that the first sidewall portion, the second sidewall portion, and a base between the first portion and the second sidewall portion define a trough the trough having a width of 10 mm to not greater than 500 mm;
wherein the trough is configured to receive a protecting deposit and retain the protecting deposit separate from the cell bottom.

10. The electrolysis cell of claim 9 , wherein the second sidewall portion comprises a cathodically polarized sidewall.

11. The electrolysis cell of claim 9 , wherein the second sidewall portion comprises a non-polarized sidewall including a stable material, wherein the stable material which includes a component of the bath chemistry further wherein, via the bath chemistry and percent saturation of the non-reactive material in the bath, the sidewall is substantially non-reactive in the molten salt electrolyte.

12. The electrolysis cell of claim 9 , further comprising a directing member, wherein the directing member is positioned between the anodically polarized sidewall and the second sidewall portion, further wherein the directing member is laterally spaced above the base of the trough, such that the directing member is configured to direct a feed material into the trough, to be retained therein as protecting deposit in the trough.

13. The electrolysis cell of claim 12 , wherein the directing member comprises: an anodically polarized material; a stable material; a cathodically polarized material; and combinations thereof.

14. A method, comprising:
passing current from an anode through a molten electrolyte bath to a cathode in an electrolysis cell;
concomitant to the first step, maintaining the bath at a temperature not exceeding 980° C.;
feeding a feed material into the electrolysis cell at a location adjacent to a cell wall, such that the feed material is retained in a trough defined adjacent to sidewall, wherein the sidewall comprises a second sidewall portion overlapping a first sidewall portion and wherein the overlap is from 0% to not greater than 90% of a total height of the cell sidewall, and wherein the sidewall comprise an anodically polarized sidewall positioned above the bottom of the cell body and adjacent to the bath-vapor interface, such that the anodically polarized sidewall is in communication with the bath-vapor interface; and
via the feeding step, maintaining the sidewall in the molten electrolyte during cell operation, wherein the sidewall is constructed of at least one component which is within about 95% of saturation in the molten electrolyte bath, wherein sidewalls of the cells are substantially free of a frozen ledge.

15. The method of claim 14 , wherein the method includes:
consuming the protecting deposit such that via consumption of the protecting deposit, metal ions are supplied to the molten electrolyte bath.

16. The method of claim 14 , further comprising:
producing a metal product from the at least one bath component.

Assignees

• Alcoa Inc
• Alcoa Usa Corp

Inventors

• Liu Xinghua
• Dimilia Robert A
• Dynys Joseph M
• Martello Jeffrey S

Classifications

• C25C3/20 Primary

  Automatic control or regulation of cells (controlling or regulating in general G05) · CPC title

• C25C3/08 Primary

  Cell construction, e.g. bottoms, walls, cathodes · CPC title

• C25C3/12

  Anodes · CPC title

• C25C7/005

  of cells for the electrolysis of melts (C25C7/02 - C25C7/06 take precedence) · CPC title

• C25C3/14

  Devices for feeding or crust breaking · CPC title