Low-profile aluminum cell potshell and method for increasing the production capacity of an aluminum cell potline

Patent metadata

Field	Value
Publication number	US-2017362725-A1
Application number	US-201515528357-A
Country	US
Kind code	A1
Filing date	Nov 20, 2015
Priority date	Nov 21, 2014
Publication date	Dec 21, 2017
Grant date	—

Abstract

An aluminum reduction cell having a shell structure with a pair of longitudinally extending sidewalls, a pair of transversely extending endwalls, a bottom wall, and an open top having an upper edge. The aluminum reduction cell also has a transverse support structure with transverse bottom beams located under the shell structure and extending transversely between the sidewalls, each of the transverse bottom beams having a pair of opposed ends. The aluminium reduction cell also has compliant binding elements fixed to the transverse support structure, each extending vertically along an outer surface of one of the sidewalls for applying an inwardly directed force said sidewall. The compliant binding elements are in the form of cantilever springs. Each spring has a metal member with a lower end which is secured to the transverse support structure, and a compliant, upper free end which is movable inwardly and outwardly in response to expansion and contraction of the shell structure.

First claim

1 - 33 . (canceled)

34 . An aluminum reduction cell, comprising:
(a) a shell structure comprising a pair of longitudinally extending sidewalls, a pair of transversely extending endwalls, a bottom wall, and an open top having an upper edge; (b) a transverse support structure comprising a plurality of transverse bottom beams located under the shell structure and extending transversely between the sidewalls, each of the transverse bottom beams having a pair of opposed ends; and (c) a plurality of compliant binding elements fixed to the transverse support structure, each extending vertically along an outer surface of one of the sidewalls, for applying an inwardly directed force said sidewall; wherein the compliant binding elements are in the form of cantilever springs, each comprising a metal member having a lower end which is secured to the transverse support structure, and a compliant, upper free end which is movable inwardly and outwardly in response to expansion and contraction of the shell structure.

35 . The aluminum reduction cell according to claim 34 , wherein the ends of the transverse bottom beams do not substantially extend beyond the sidewalls of the shell structure.

36 . The aluminum reduction cell according to claim 35 , wherein the lower end of each of the compliant binding elements is rigidly secured to one of the ends of one of the transverse bottom beams.

37 . The aluminum reduction cell according to claim 34 , wherein each of the compliant binding elements extends vertically along an outer surface of one of the sidewalls.

38 . The aluminum reduction cell according to claim 37 , wherein each of the compliant binding elements is in contact with the outer surface of the sidewall along at least a portion of its length.

39 . The aluminum reduction cell according to claim 34 , wherein the upper end is located at or below the upper edge of the shell structure.

40 . The aluminum reduction cell according to claim 39 , wherein at least some of the compliant binding elements are attached, rigidly or flexibly, over parts of their length, to the sidewall.

41 . The aluminum reduction cell according to claim 39 , wherein each of the compliant binding elements is of sufficient length such that a main point of load transfer to the sidewalls is approximately at the tops of cathode blocks lining the bottom wall of the aluminum reduction cell.

42 . The aluminum reduction cell according to claim 34 , wherein each of the compliant binding elements comprises a metal plate.

43 . The aluminum reduction cell according to claim 42 , wherein the metal plate has a thickness, width and composition such that the upper end is compliant, and such that the compliant binding element maintains an inwardly directed compressive force on the shell structure during outward dilation and inward contraction of the shell structure.

44 . The aluminum reduction cell according to claim 43 , wherein the thickness and/or width of each of the compliant binding elements is varied along its length, with the upper end of the compliant binding element being reduced in width and/or thickness relative to the lower end, such that the upper end is more compliant than the lower end.

45 . The aluminum reduction cell according to claim 34 , wherein each of the compliant binding elements is designed such that, during normal operation of the aluminum reduction cell, they are at a first applied load; and
such that, in response to an expected reduction in process temperature, the compliant binding elements are at a second load which is greater than a minimum binding load; wherein the minimum binding load is a load at which forces opposing contraction of a lining of the aluminum reduction cell are overcome, thereby preventing formation of gaps in the lining during contraction in response to a thermal cycle comprising a deviation of about +/−100-150° C. from a normal operating temperature of the aluminum reduction cell.

46 . The aluminum reduction cell according to claim 34 , wherein the compliant binding elements comprise a mild or low-alloy steel.

47 . The aluminum reduction cell according to claim 34 , wherein the compliant binding elements have a depth of no more than about 200 mm.

48 . The aluminum reduction cell according to claim 47 , wherein the compliant binding elements have a depth from about 50 mm to about 200 mm.

49 . The aluminum reduction cell according to claim 34 , wherein the compliant binding elements are provided with adjustment means, and wherein the adjustment means are located between the upper ends of the compliant binding elements and the shell structure.

50 . A method for improving the productivity of an aluminum reduction cell potline housed in an enclosure having a length and a width;
wherein the potline comprises a plurality of existing aluminum reduction cells, each of said existing cells including an existing potshell and an existing support structure and having a first footprint defined by an area of the existing potshell and the existing support structure, wherein the existing potshell and the existing support structure each have a length extending across the width of the enclosure, and the length of the existing support structure is greater than the length of the existing potshell; the method comprising:
(a) removing one or more of said existing aluminum reduction cells from the potline; and
(b) inserting one or more new aluminum reduction cells with a potshell according to claim 34 into the potline, wherein each of the new cells comprises a new potshell and a new base structure and is inserted into a space vacated by one of the existing cells;
wherein each of the new cells has a second footprint which is substantially the same as the first footprint, and wherein the new potshell has a length which is substantially the same as a length of the new support structure, such that the area of the new potshell is greater than an area of the existing potshell.

51 . The method according to claim 50 , whereupon increasing the width of the cells results in an increase in the operating current of the cells, so that the current density of the cathode remains substantially the same as before the capacity increase.

52 . An aluminum reduction potline, comprising aluminum reduction cells connected in series, and further comprising:
(a) support plinths; (b) bus-bars and risers; (c) superstructures, carrying anodes; (d) off-gas ducts; (e) a feed distribution system; and (f) other known ancillaries; where the aluminum reduction cells are furnished with aluminum reduction cells according to claim 34 .

Assignees

• Hatch Ltd

Inventors

• Jastrzebski Maciej Urban
• Shaw John Andrew Ferguson
• Pearen Dale
• Wasmund Bert O
• Richard Daniel

Classifications

• C25C3/08

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

• C25C3/10 Primary

  External supporting frames or structures · CPC title