WO2005051833A1

WO2005051833A1 - Device for handling an electrolytic cell which is intended for the production of aluminium

Info

Publication number: WO2005051833A1
Application number: PCT/FR2004/002972
Authority: WO
Inventors: Patrick Delescluse; Alain Van Acker
Original assignee: E.C.L.
Priority date: 2003-11-24
Filing date: 2004-11-22
Publication date: 2005-06-09
Also published as: AR046659A1; RU2006122527A; EP1687233A1; FR2862663A1; ATE426572T1; CA2545335A1; CN1886329A; UA86956C2; AU2004293215A1; DE602004020256D1; AU2004293215B2; CA2545335C; MY141828A; CN100467366C; ZA200603518B; EP1687233B1; RU2329192C2; BRPI0416862A; FR2862663B1

Abstract

The invention relates to a device for handling (300) an electrolytic cell (11) which is intended for the production of aluminium by means of fused-salt electrolysis. According to the invention, the cell is rectangular and comprises a metal casing (12) which is equipped with a rim (14a, 14b) along at least the long sides (17a, 17b) thereof. The inventive handling device (300) consists of at least one hook means (301, 301') which enables same to be gripped by a lifting and handling unit (20) and a frame (310) comprising a plurality of fixing means (320) which are distributed such as to enable the frame (310) to be fixed securely to the casing (12) at a plurality of determined locations. According to the invention, the handling device (300) can be used to maintain the deformation of the casing (12) of the cell (11) within a determined tolerance range when it is suspended by a lifting and handling unit (20).

Description

DEVICE FOR HANDLING AN ELECTROLYSIS TANK FOR THE PRODUCTION OF ALUMINUM

Field of the invention

The invention relates to plants for the production of aluminum by igneous electrolysis according to the Hall-Héroult process. It relates more particularly to the handling devices used in said factories.

State of the art

Aluminum metal is produced industrially by igneous electrolysis, namely by electrolysis of alumina in solution in a bath of molten cryolite, called electrolyte bath, according to the well-known Hall-Héroult process. The electrolysis cells intended for the production of aluminum comprise a tank provided with cathodes and anodes in carbonaceous material partially immersed in the electrolyte bath. The tank comprises a steel box, covering elements made of refractory materials and a cathode assembly located at the bottom of the tank. French patent application FR 2 806 742 (corresponding to American patent US 6 409 894) describes in more detail the typical structure of factories intended for the production of aluminum and the cells which they contain.

In operation, an electrolysis plant requires interventions on the electrolysis cells, such as anode changes and cell repairs. To carry out these interventions, the most modern factories are equipped with lifting and handling units comprising an overhead crane, which can be translated above and along the electrolysis cells, and at least one trolley. fitted with handling and intervention devices.

The repair of a tank includes operations of "unbrasking" and "rebrasking" of these. These operations are intended to renew the crucible formed by the interior lining and cathode elements of the tank. These operations can be carried out on site, that is to say without removing the cell from the corresponding cell, but they can adversely affect the functioning of the cells and the maintenance of the electrolysis rooms. In fact, these operations generate dust, cause new and used materials to come and go in the electrolysis rooms and reduce the production of a series of cells by stopping the corresponding cell during the work. In order to avoid these drawbacks, it is preferable to carry out the repair of the tanks in a specific room intended for the repair of the tanks and situated outside the electrolysis room.

The lifting and handling units used to transport the electrolysis cells between the repair room and the electrolysis room (s) generally include one or two carriages fitted with lifting means. During repair operations, one or more spreaders are generally fixed to the tank casing and the tank is handled by means of the spreader (s). However, the known means have the drawback of not controlling the deformation of the tank under the effect of its own weight, which would risk causing deterioration of the "pot lining" which could significantly limit the duration of use of the tank. . The Applicant has therefore sought means which make it possible to avoid these drawbacks.

Description of the invention

The invention relates to a device for handling an electrolysis cell tank intended for the production of aluminum by igneous electrolysis, said tank being rectangular, having a main axis X and comprising a metal box provided with a rim at least on the long sides of the tank, said device comprising at least one hooking means intended to allow its gripping by a lifting and handling unit and being characterized in that it comprises an armature provided with a plurality of rigid fixing means distributed so as to allow rigid fixing of the frame to the box at a plurality of determined locations. The Applicant has had the idea of stiffening the tank using at least one rigid element, namely said frame, interposed between the tank and the lifting and handling unit and rigidly fixed in several places of the box. tank. The reinforcement allows the deformation of the tank casing to be maintained - in particular by longitudinal bending (that is to say in the long direction of the tank) - within a determined tolerance range when it is suspended by a unit of lifting and handling and thus avoid damage to the inner lining of the tank during tank handling operations.

The distribution of the plurality of fastening means on the frame distributes the load on the frame, in particular in the direction of the length of the tank, and thus makes it possible to minimize the deformation of the box under the effect of the weight of the together by bringing this deformation closer to that of the device. The determined fixing locations are typically distributed over a determined portion of the periphery of the box. This portion typically covers at least 70% of the long sides of the tank, in order to minimize the "floating" (not fixed) part of the tank.

The deflection deflection of the armature, under the action of its own weight and that of the tank to which the device is fixed, is preferably less than ± 5 mm over the entire length of the armature (in the direction along the tank), and more preferably less than or equal to ± 2 mm.

Preferably, the frame comprises one or two longitudinal beams intended to be arranged in the direction of the length of the tank. In the first case, the beam is typically provided with arms and the fixing means are located at the end of these arms. In the second case, the beams are preferably parallel to each other and are linked by at least one cross member, and the fixing means are preferably distributed over the beams, possibly at the end of the arms, so to allow the attachment of each beam to the corresponding long side of the tank. In a preferred embodiment of the invention, the handling device further comprises adjustable spacers intended to compensate for any geometry faults of the frame and / or of the box.

The invention also relates to the use of a device according to the invention in a factory for the production of aluminum by igneous electrolysis.

The invention also relates to a method of handling an electrolysis cell tank intended for the production of aluminum by igneous electrolysis, which can be implemented using a handling device according to the invention.

The invention is described in detail below using the attached figures.

FIG. 1 illustrates a typical electrolysis room intended for the production of aluminum and equipped with a lifting and handling unit.

FIG. 2 schematically represents, in top view, possible variants of the frame of the handling device according to the invention.

Figures 3 to 5 illustrate a preferred embodiment of the handling device according to the invention.

Figure 3 shows the device in transverse view (A) and in side view (B). Figure 3 (A) corresponds to the section plane A- A of Figure 3 (B). Figure 3 (B) corresponds to the section plane BB of Figure 3 (A). FIG. 3 (B) also illustrates, schematically, an electrolysis cell (2) and a lifting and handling unit (20) during handling of the tank (11). Figure 4 shows the device in partial cross-section. Figure 4 (B) illustrates in more detail part of a means for fixing the tank to the handling device. Figure 5 illustrates in more detail, in side view, the embodiment of the handling device illustrated in Figures 3 and 4. Figure 4 corresponds to the section plane CC of Figure 5. Figure 5 corresponds to the section plane DD of figure 4. In Figures 2 to 5, the handling device (300) is fixed to a tank (11) in order to illustrate the relative positioning of these elements.

The electrolysis plants for the production of aluminum include one or more electrolysis rooms (1) comprising a large number of electrolysis cells (2) (typically several hundred cells), each electrolysis cell (2 ) comprising a tank (11) and anodes (10). As illustrated in Figure 1, the tanks (11) generally have an elongated rectangular shape having a main axis X; the tanks (11) have a length Lo generally greater than 3 times their width Wo. The main axis X of a tank (11) is located in the direction of its length and typically passes through the center of mass of the tank.

As illustrated in the figures, in particular Figures 3 to 5, each tank (1 1) comprises a metal box (12) which comprises a box (13), a flange (14) and stiffeners (15) distributed along from the cash register. The rim (14) typically has at least lateral rims (14a, 14b) on the long sides (17a, 17b) of the tank and end rims (14c, 14d) on the short sides (17c, 17d) of tank. The stiffeners (15) generally include reinforcements (16) arranged perpendicular to the outer surface of the body (13). The box (12) is coated internally with covering elements made of refractory materials (not shown) and contains a cathode assembly (not shown).

The tank (11) can be put in place or removed using a lifting and handling unit (20) able to be moved along the electrolysis cells on raceways (3, 3 ') using rolling means (23, 23 '). Figure 1 illustrates a typical lifting and handling unit, viewed from the side (Figure 1 (A)) and viewed along the main axis (Figure 1 (B)).

Said unit (20) typically comprises an overhead crane (21), at least one carriage (22, 22 ') capable of being moved on the overhead crane (21), and handling members (24, 24') which typically include at least one lifting device (25, 25 '), such than a hoist. The tank (11) is connected to the lifting device (25, 25 ') by removable connecting means (30, 30') which generally include separate lifting beams (31, 31 ') (called "lifting beams" in English) and articulated attachment means (32, 32 '), such as links or articulated levers, which allow an oscillating movement around the connection points. The lifting beams (31, 31 ') are arranged transversely to the tank (11) and are fixed to the lifting device (25, 25') by hooking means (33, 33 '). The attachment means (32, 32 ') provide an isostatic connection between the lifting device (s) (25, 25') and the tank (11). The known connecting means (30, 30 ') allow longitudinal and transverse deformations of the tank.

According to the invention, the tank (11) is fixed to the lifting device (25, 25 ') by means of a handling device (300) intended to stiffen the box and to limit its deformation. The assembly formed by the tank (11) and the handling device (300) can then be handled as a whole by the lifting and handling unit (20).

The handling device (300) according to the invention comprises:

- at least one attachment means (301, 301 ') intended to allow it to be grasped by a lifting and handling unit (20);

- A frame (310) provided with a plurality of rigid fixing means (320) distributed so as to allow rigid fixing of the frame (310) to the box (12) in a plurality of determined locations.

The rigid fixing means (320) provide a hyperstatic connection between the lifting device (s) (25, 25 ') and the tank (11).

The attachment means or means (301, 301 ') are normally able to be connected to the lifting devices (25, 25') of the lifting and handling unit (20). They are typically chosen from through holes, bolting systems and hooks. The handling device (300) advantageously comprises at least two attachment means (301, 301 '). These are located at a determined distance from each other and are preferably sufficiently distant from each other to avoid the pitching of the box during handling. This variant also makes it possible to limit the deformation of the armature (310) under the effect of the combined weights of the tank and the handling device.

As illustrated in FIG. 2, the frame (310) preferably comprises at least one longitudinal beam (311, 311a, 311b) and a plurality of rigid fixing means (320) distributed along each beam (311, 311a, 311b), so as to allow rigid fixing of the frame (310) at least on the long sides (17a, 17b) of the box (12). These beams (311, 311a, 311b) are intended to be arranged in the direction of the length of the tank. The fixing means (320) are optionally located at the end of the arms (313) fixed to the or to each beam (311, 311a, 311b).

Each longitudinal beam (311, 311a, 311b) has a length L which is advantageously greater than 70% of the length Lo of the tank (11), and preferably greater than 80% of Lo.

In a first embodiment of the invention, the frame (310) comprises a longitudinal beam (311), preferably a single beam, intended to be placed parallel to the main axis X of the tank (11) and to the above it. In the variant illustrated in FIG. 2 (A), the longitudinal beam (311) is provided with arms (313) distributed along the beam, typically with regular spacings, and the fixing means (320) are located at the end of these arms. In this embodiment, the attachment means (301, 301 ′) is (are) typically provided (s) on the beam (311).

In another embodiment of the invention, two variants of which are illustrated in FIGS. 2 (B) and 2 (C), the frame (310) comprises two longitudinal beams

(311a, 311b) parallel to each other, linked to each other by at least one transverse bar or "crosspiece" (315, 315 '), and intended to be placed parallel to the axis main X of the tank (11) and to be fixed each to a long side (17a, 17b) corresponding to the box (12). The fixing means (320) are distributed over the beams, possibly at the end of the arms (313). The longitudinal beams (311a, 311b) typically have the same length L. In this embodiment, the attachment means (301, 301 ′) is (are) advantageously provided on the or the sleepers (315, 315 ').

In the variant illustrated in Figure 2 (C), the two longitudinal beams (311a, 311b) are arranged so that they can be placed, in whole or in part, above each of the corresponding flanges (14a, 14b) of the box (12) located on the long sides (17a, 17b) thereof. This variant has the advantage of allowing a significant reduction in the weight of the frame (310). It also has the advantage of being simpler to produce.

Figures 3 to 5 illustrate, without limitation, a particular variant of the embodiment of the invention of Figure 2 (C).

The cross member (s) (315, 315 ') make it possible to limit the lateral deformations of the frame (310). They can be removable, but they are preferably integral with the longitudinal beams (311a, 311b) in order to impart greater rigidity to the device.

The frame (310) advantageously comprises at least two crosspieces (315, 315 '), each provided with a hooking means (301, 301'). This variant makes it possible to limit the deflection of the longitudinal beams (311a, 311b) under the effect of the combined weights of the tank and the handling device.

The beam (s) (311, 311a, 311b) may possibly include reinforcements (312) to reinforce and stiffen them; these reinforcements are typically plates arranged transversely to the main axis of the beams. The beams (311, 311a, 311b) are typically formed of an elongated box of large section and having a high flexural inertia. The number of separate fixing means (320) depends on the dimensions of the tank. It is greater than or equal to 4 and typically greater than 10. The maximum distance between the fixing means on the long sides of the tank is typically around 2 meters. The fixing means are typically distributed uniformly in order to simplify the design and use of the device. The average distance between the fixing means is typically between 0.5 and 2 meters.

The fixing means (320) are preferably chosen from the means which make it possible to firmly, but removably fix, the box (12) to the frame (310), such as the bolt and nut systems.

The fixing means (320) advantageously comprise tie rods (321) capable of bearing on the handling device (300) - typically on each longitudinal beam (311a, 311b) of the device - on the one hand, and on the box (12), on the other hand. To this end, the tie rods (321) advantageously comprise a rod (322), which is typically threaded - at least at its two ends - so as to allow its fixing using nuts (323, 324). In practice, the rod (322) can pass through openings (19, 19 ') arranged in the flanges (14) of the box. The tie rods (321) exert a force upwards on the box (12) and downwards on the handling device (300), which makes it possible to press, directly or indirectly, the box on the handling device and, thus, to stiffen the box using the handling device.

In order to distribute the load on the stiffeners (15), the fixing means (320) may include support bars (325) capable of bearing on the stiffeners (15) of the box. This variant of the invention is advantageously implemented with boxes in which the stiffeners (15) have openings (18) capable of allowing the insertion of said support bars (325) (see FIGS. 4 and 5) . The support bars (325) can be formed of several elements (for example, two separate bars (325, 325 ') arranged in parallel and separated by spacers (326)). The openings (18) are advantageously reinforced with reinforcements (18 '), which typically take the form of a section of tube.

In a preferred embodiment of the invention, the handling device (300) further comprises a plurality of spacers (330) (or "adjustable cylinders") intended to adjust the spacing E between the box (12) and the handling device (300) (typically between the flanges (14) of the box (12) and the longitudinal beams (311a, 311b)). The spacers also make it possible to provide determined support points between the box (12) and the handling device (300). The spacers (330) make it possible to precisely adapt the handling device (300) to the box (12) and to avoid adding additional deformation to the box. In fact, the Applicant has noted that the caissons are often slightly deformed and that the bearing of the longitudinal beams on the caisson, without an additional adjustment element, could cause additional deformation of the caisson. The spacers (330) are preferably placed so as to bear on the most rigid parts of the box (12) (in particular of the edges (14) of the box, typically at the level of the reinforcements (14 ′)). The spacers (330) are typically aligned with the support points (18) of the tie rods on the box, as illustrated in FIG. 5. The spacers (330) are typically chosen from screw jacks.

The subject of the invention is also a method of handling an electrolytic cell tank intended for the production of aluminum by igneous electrolysis, comprising:

- the supply of a handling device (300) according to the invention;

- The installation of the handling device (300) on the box (12) of a tank (11);

- The fixing of the handling device (300) on the box using the fixing means (320);

- Attaching the handling device (300) to a lifting and handling unit (20) - typically to the handling devices (24, 24 ') of such a unit (20) - using at least a hooking means (301, 301 ').

The tank can then be lifted, transported and deposited. When the handling device (300) comprises spacers (330), the method further comprises adjusting a spacing E between the box (12) and the handling device (300) using said spacers (330 ).

When the frame (310) of the handling device (300) comprises at least two longitudinal beams (311a, 311b), the positioning of the handling device (300) on the box (12) of a tank (11) typically comprises an alignment of these longitudinal beams (311a, 311b) with the lateral edges (14a, 14b) of the box (12) located on its long sides (17a, 17b).

When the handling device (300) comprises tie rods (321), the beams (311a, 311b) are fixed to the box (12) by tightening until the box presses against said beams or, if necessary, against the retractors (330). When using spacers (330), these are preferably adjusted before the final tightening of the tie rods (321).

The spacers (330) are preferably integrated into the handling device (300) in order to simplify the use of the handling device (300) or the implementation of the method according to the invention. The spacers (330) may possibly be, in whole or in part, separate from the device or removable. When the spacers (330) are separated from the handling device when it is put in place, the method further comprises placing a plurality of spacers (330), typically by insertion, between the frame (310 ) and the box (12).

Claims

1. Handling device (300) of a cell (11) of electrolysis cell (2) intended for the production of aluminum by igneous electrolysis, said cell being rectangular, having a main axis X and comprising a metal box ( 12) provided with a rim (14) at least on the long sides (17a, 17b) of the tank (11), said device (300) comprising at least one hooking means (301, 301 ') intended to allow gripping by a lifting and handling unit (20) and being characterized in that it comprises a frame (310) provided with a plurality of rigid fixing means (320) distributed so as to allow a rigid fixing of the frame (310) to the box (12) in a plurality of determined locations.

2. Handling device (300) according to claim 1, characterized in that it comprises at least two attachment means (301, 301 ').

3. Handling device (300) according to any one of claims 1 or 2, characterized in that the frame (310) comprises at least one longitudinal beam (311, 311a, 311b) and a plurality of rigid fixing means (320) distributed along each beam (311, 311a, 311b), so as to allow rigid fixing of the frame (310) at least on the long sides (17a, 17b) of the box (12).

4. Handling device (300) according to claim 3, characterized in that the fixing means (320) are located at the end of arms (313) fixed to the or each beam (311, 311 a, 311 b ).

5. Handling device (300) according to any one of claims 3 or 4, characterized in that the frame (310) comprises a longitudinal beam (311) intended to be placed parallel to the main axis X of the tank (11) and above it.

6. Handling device (300) according to claim 5, characterized in that the attachment means or (301, 301 ') are provided on said beam (311).

7. Handling device (300) according to any one of claims 3 or 4, characterized in that the frame (310) comprises two longitudinal beams (311a, 311b) parallel to each other, linked to one to the other by at least one crosspiece (315, 315 '), and intended to be placed parallel to the main axis X of the tank (11) and to be fixed each to a long side (17a, 17b) corresponding of the box (12).

8. Handling device (300) according to claim 7, characterized in that the attachment means or (301, 301 ') are provided on the cross member (s) (315, 315').

9. Handling device (300) according to any one of claims 7 or 8, characterized in that the frame (310) advantageously comprises at least two crosspieces (315, 315 '), each provided with a means of hanging (301, 301 ').

10. Handling device (300) according to any one of claims 7 or 9, characterized in that each crosspiece (315, 315 ') is integral with the longitudinal beams (31 la, 31 lb).

11. Handling device (300) according to any one of claims 7 or 10, characterized in that the longitudinal beams (311a, 311b) are arranged so that they can be placed, in whole or in part, above each corresponding flanges (14a, 14b) of the box (12) located on its long sides (17a, 17b).

12. Handling device (300) according to any one of claims 1 to 11, characterized in that the fixing means (320) comprise tie rods (321) capable of bearing on the handling device (300), d 'on the one hand, and on the box (12), on the other hand.

13. Handling device (300) according to any one of claims 1 to 12, characterized in that it further comprises a plurality of spacers (330) intended to adjust the spacing E between the box (12) and the device (300).

14. Handling device (300) according to claim 13, characterized in that the spacers (330) are chosen from screw jacks.

15. Use of a handling device (300) according to any one of claims 1 to 14 in a factory for the production of aluminum by igneous electrolysis.

16. A method of handling a cell (11) of an electrolysis cell intended for the production of aluminum by igneous electrolysis, comprising: - the supply of a handling device (300) according to any one of claims 1 at 14; - the installation of a handling device (300) on the box (12) of a tank (11); - The fixing of the handling device (300) on the box using the fixing means (320); - Attaching the handling device (300) to a lifting and handling unit (20) using at least one attachment means (301, 301 ').

17. A handling method according to claim 16, further comprising the establishment of a plurality of spacers (330) between the frame (310) and the box (12).

18. A method of handling a cell (11) of an electrolysis cell intended for the production of aluminum by igneous electrolysis, comprising: - the supply of a handling device (300) according to any one of claims 13 or 14; - the installation of a handling device (300) on the box (12) of a tank (11); - The adjustment of a spacing E between the box (12) and the handling device (300) using said spacers (330);

- Attaching the handling device (300) to a lifting and handling unit (20) using at least one attachment means (301, 301 ').