Systems and methods of protecting electrolysis cells

Patent metadata

Field	Value
Publication number	US-9340887-B2
Application number	US-201414206506-A
Country	US
Kind code	B2
Filing date	Mar 12, 2014
Priority date	Mar 13, 2013
Publication date	May 17, 2016
Grant date	May 17, 2016

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 apparatus, comprising:
an electrolysis cell is provided, 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 polarized sidewall portion, and
a non-polarized sidewall portion; wherein the non-polarized sidewall portion is configured to extend out from the sidewall and provide a stepped configuration, wherein non-polarized sidewall portion comprises a stable material:

wherein the polarized sidewall portion and the non-polarized sidewall portion are adjacent to each other and wherein the non-polarized sidewall portion and the polarized sidewall portion are configured in liquid communication with the molten electrolyte bath.

2. The apparatus of claim 1 , wherein the polarized sidewall portion is one of:
an anodically polarized sidewall, a cathodically polarized sidewall, and combinations thereof.

3. The apparatus of claim 2 , 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.

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

5. The apparatus of claim 1 , wherein the non-polarized sidewall portion is positioned above the cathodically polarized sidewall and is in communication with the bath-air interface.

6. The apparatus of claim 1 , wherein the non-polarized sidewall portion is selected from the group consisting of:
a thermal conductor; a frozen ledge device, and combinations thereof.

7. The apparatus of claim 6 , wherein when the non-polarized sidewall portion comprises the thermal conductor, wherein the thermal conductor is adjacent to the polarized sidewall portion and in liquid communication with at least one of: (a) a metal pad and (b) a cell bottom, wherein the thermal conductor is configured to accept heat from the molten electrolyte bath adjacent to a thermal conductor contact point, wherein, via the thermal conductor, a frozen ledge is formed between the thermal conductor and molten electrolyte bath along the portion of the sidewall where the thermal conductor contacts the molten electrolyte.

8. The apparatus of claim 6 , 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 an anodically polarized sidewall.

9. The apparatus of claim 6 , wherein the non-polarized sidewall comprises the frozen ledge device, wherein the frozen ledge device is configured to attach to the sidewall and extract heat from the molten salt bath adjacent to the frozen ledge device to define a frozen ledge along a portion of the sidewall adjacent to the frozen ledge device.

10. The apparatus of claim 1 , wherein the cell is further comprises a feeder configured to provide a feed material into the bath, where the feeder is retained along at least a portion of the sidewall.

11. An electrolysis cell is provided, 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:
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 and further wherein the anodically polarized sidewall portion is in liquid communication with the molten electrolyte bath.

12. An electrolysis cell sidewall, 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; and
a second sidewall portion configured to extend up from the bottom of the cell body,
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;
wherein the trough is configured to receive a protecting deposit and retain the protecting deposit separate from the cell bottom.

13. The system of claim 12 , wherein the second sidewall portion comprises a cathodically polarized sidewall.

14. The system of claim 12 , 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.

15. The system of claim 12 , 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.

16. The system of claim 15 , wherein the directing member comprises: an anodically polarized material; a stable material; a cathodically polarized material; and combinations thereof.

17. The system of claim 12 , wherein the lateral spacing is not greater than 6 inches.

18. An electrolysis cell sidewall is provided, comprising:
a cell body having a bottom and at least one sidewall, wherein the cell body is configured to retain the molten electrolyte bath, wherein the sidewall comprises:
a first sidewall portion, configured to it onto a thermal insulation package of the sidewall and retain the electrolyte, the first sidewall portion comprising a non-polarized sidewall portion; and
a second sidewall portion comprising a cathodically polarized sidewall, the second sidewall portion configured to extend up from the bottom of the cell body, wherein the second sidewall portion is longitudinally spaced from the first sidewall portion, wherein the first sidewall portion, the second sidewall portion, and a base between the first portion and the second portion define a trough;
wherein the trough is configured to receive a protecting deposit and retain the protecting deposit separately from the cell bottom.

19. An assembly is provided, 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 comprising an anodically polarized sidewall, wherein the anodically polarized sidewall is configured to fit onto a thermal insulation package of the sidewall and retain the electroly

Assignees

• Alcoa Inc
• Alcoa Inc

Inventors

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

Classifications

• C25C7/005

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

• C25C3/08 Primary

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

• C25C7/06 Primary

  Operating or servicing · CPC title

• C25D17/04

  External supporting frames or structures · CPC title

• C25C3/14

  Devices for feeding or crust breaking · CPC title