Systems and methods of electrolytic production of aluminum

Patent metadata

Field	Value
Publication number	US-2018282889-A1
Application number	US-201815943171-A
Country	US
Kind code	A1
Filing date	Apr 2, 2018
Priority date	Mar 31, 2017
Publication date	Oct 4, 2018
Grant date	—

Abstract

In some embodiments, an exemplary electrolytic cell includes: a cathode structure disposed within an electrolysis cell, wherein the electrolysis cell is configured to produce metal on a surface of the cathode structure, wherein the cathode structure is configured to fit along a floor of the electrolysis cell, wherein the cathode structure has a sloped surface when compared to a generally horizontal plane, and wherein via the sloped surface, the cathode structure is configured to drain a metal product from the sloped surface towards a lower end of the cathode structure.

First claim

1 . An apparatus, comprising:
a cathode structure disposed within an electrolysis cell, wherein the electrolysis cell is configured to produce metal on a surface of the cathode structure,
wherein the cathode structure is configured to fit along a floor of the electrolysis cell,
wherein the cathode structure has a sloped surface when compared to a generally horizontal plane,
wherein via the sloped surface, the cathode structure is configured to drain a metal product from the sloped surface towards a lower end of the cathode structure, and
wherein the lower end of the cathode structure connects to the floor of the electrolysis cell.

2 . The apparatus of claim 1 , wherein the cathode structure has a triangular geometry.

3 . The apparatus of claim 1 , wherein the sloped surface of the cathode structure has a wall angle of 15 degrees to not greater than 89 degrees.

4 . The method of claim 1 , wherein a height of the cathode structure is from 5% to 95% of a height of a molten bath within the electrolytic cell.

5 . The apparatus of claim 1 , wherein an upper end of the cathode structure is angled.

6 . The apparatus of claim 5 , wherein the upper end of the cathode structure has an arcuate edge.

7 . The apparatus of claim 1 , wherein the cathode structure is a monolithic member attached to the floor of the electrolytic cell.

8 . The apparatus of claim 7 , wherein the lower end of the monolithic member comprises a mechanical attachment device configured to enable mechanical attachment of the monolithic member to the cell floor.

9 . The apparatus of claim 7 , wherein the lower end of the monolithic member comprises an adhesive configured to enable mechanical attachment of the monolithic member to the cell floor.

10 . The apparatus of claim 1 , wherein the cathode structure comprises at least two cathode plates attached to a support member, wherein the cathode plates, and not the support member, are in contact with the molten electrolyte bath.

11 . The apparatus of claim 1 , wherein the cathode structure comprises at least two cathode plates mechanically attached to the cell floor, wherein the at least two cathode plates and the cell bottom define an empty volume.

12 . The apparatus of claim 1 , wherein the cathode assembly comprises a plurality of cathode structures configured in a generally parallel, interspaced configuration along the floor of an electrolysis cell.

13 . The apparatus of claim 1 , wherein the cathode structures are configured as part of carbon blocks along the floor of the cell, with an aluminum wettable coating covering the carbonaceous material.

14 . The apparatus of claim 1 , wherein the cathode structures are configured as non-aluminum wettable components along the floor of the cell, with an aluminum wettable coating covering the non-aluminum wettable components.

15 . The apparatus of claim 1 , wherein the cathode structures comprise a plurality of tiles adhered into place over a carbon block with an adhesive such that the adhesive and tiles cooperate in the cathode wall angle as a metal drained cathode surface.

16 . The apparatus of claim 1 , wherein the metal produced at the cathode structure flows to a floor of the cell, wherein the floor has a cathode drain angle.

17 . The apparatus of claim 16 , further comprising a collection area positioned adjacent to a cathode area in the electrolytic cell, wherein the cathode drain angle is configured to direct metal product to the collection area.

18 . The apparatus of claim 16 , wherein the cathode drain angle is from 0 degree to 15 degrees.

19 . An apparatus, comprising:
a. a cathode assembly comprising a cathode structure electrically configured in an aluminum electrolysis cell to electrolytically participate in metal production, wherein the metal is produced on a surface of the cathode structure, b. wherein the cathode structure is configured to fit along a floor of the aluminum electrolysis cell, c. further wherein the cathode structure has a cathode wall angle with a sloped configuration when compared to a generally horizontal plane, d. wherein via the cathode wall angle, the cathode structure is configured to drain a metal product from a surface thereof towards the floor of the cell, and e. wherein the cathode structure is further configured with a cathode drain angle along the floor of the cell, such that the metal product drained via the cathode wall angle is further directed along the floor of the cell by the cathode drain angle into a collection area positioned adjacent to a cathode area in the electrolytic cell.

20 . The apparatus of claim 19 , wherein the collection area is located along an inner region of the cathode assembly.

21 . The apparatus of claim 20 , the collection area is located at least one of: along at least one sidewall of the cell, along at least one end wall of the cell.

22 . The apparatus of claim 19 , wherein the cathode assembly is configured with a horizontal portion between the cathode structure and the collection area.

23 . The apparatus of claim 19 , further comprising:
a. an anode assembly, configured from a plurality of anodes, wherein each anode is a monolithic block of carbon having an anode profile configured to correspond to the cathode wall angle of the cathode assembly; b. wherein the cathode structures of the cathode assembly and the anodes of the anode assembly are separated by an anode-to-cathode distance filled with molten electrolyte.

24 . The apparatus of claim 23 , wherein the anode-to-cathode distance is ¼″ to 2″.

25 . The apparatus of claim 23 , wherein the anode profile is configured with beveled edges.

26 . The apparatus of claim 23 , wherein each anode is further configured with at least one anode slot configured along a lower end of the anode, wherein the at least one anode slot is configured to direct trapped gasses away from the lower end of the anode and into the molten electrolyte bath.

27 . A method, comprising:
a. during rebuild of an electrolytic cell, mechanically attaching a cathode assembly to a cell bottom, wherein the cathode assembly is configured with a plurality of cathode structures constructed of an aluminum wettable material, wherein each cathode structure comprises a cathode wall angle to promote a metal product to drain from an upper or middle portion of the cathode structure to a lower portion of the cathode structure; and b. after the electrolytic cell is preheated, positioning an anode assembly comprising a plurality of anodes, wherein the anodes are configured with a beveled edge corresponding generally to the cathode wall angle, such that the anode-to-cathode distance is constant whether measured between the corresponding generally horizontal portions of the cathode assembly and anodes or when measured between the cathode structures having a cathode wall angle and the beveled edge of the anodes.

28 . The method of claim 27 , further comprising:
heating a molten salt bath configured in the cell; feeding a feedstock material into the cell, wherein the feedstock contains a metal compound of the desired metal product; and electrolytically producing metal in the cell.

29 . The method of claim 27 , wherein one or more cathode assemblies are retrofitted into an existing electrolysis cell for metal production.

Assignees

• Alcoa Usa Corp

Inventors

• Liu Xinghua

Classifications

• C25C3/12 Primary

  Anodes · CPC title

• C25C7/02

  Electrodes (consumable anodes for the refining the metals C25C1/00 - C25C5/00); Connections thereof · CPC title

• C25C3/08 Primary

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

• Y02P10/20

  Recycling · CPC title

• C25C7/025

  used in cells for the electrolysis of melts · CPC title