EP3099843A1

EP3099843A1 - Device for storing a load above an electrolytic cell

Info

Publication number: EP3099843A1
Application number: EP15740471.6A
Authority: EP
Inventors: Marc BEYSSON; Stéphane Petit
Original assignee: Rio Tinto Alcan International Ltd
Current assignee: Rio Tinto Alcan International Ltd
Priority date: 2014-01-27
Filing date: 2015-01-23
Publication date: 2016-12-07
Anticipated expiration: 2035-01-23
Also published as: EP3099843B1; AU2019202943B2; WO2015110902A1; AU2019202943A1; EP3099843A4; CN105960482B; AU2015208856A1; FR3016891B1; CN105960482A; RU2686184C2; DK179626B1; CA2935446C; CA2935446A1; DK201670542A1; RU2016134826A3; FR3016891A1; RU2016134826A

Abstract

The invention relates to a device (1) for storing a load above an electrolytic cell (100) comprising a shell (102), hoods (120), a cathode (104) and anodic assemblies (106) arranged in the shell (102) and covered by the hoods (120), the load storage device (1) comprising supporting means whereon the load to be stored above the cell (100) is to be arranged, and bearing means designed to allow the supporting means to rest in a stable manner above the electrolytic cell (100), especially above the anodic assemblies (106) and the hoods.

Description

DEVICE FOR STORING A LOAD ABOVE A TANK

ELECTROLYSIS

The present invention relates to a device for storing a charge for an electrolytic cell, a storage system comprising this device, an electrolysis cell and an electrolysis plant comprising this device, as well as a method for changing the charge. an anode assembly using this storage device.

Aluminum is conventionally produced in aluminum smelters, by electrolysis, according to the Hall-Héroult process.

An aluminum smelter traditionally comprises several hundred electrolytic cells connected in series and traversed by an electrolysis current whose intensity can reach several hundreds of thousands of amperes. The electrolysis tanks are arranged transversely to the flow direction of the electrolysis current at the scale of the series. Two adjacent electrolysis tanks of the series are separated by an inter-tank alley. A wider operating aisle, substantially perpendicular to a longitudinal direction of the tanks and inter-tank aisles, extends along the series to allow access and movement of vehicles and personnel on foot.

Electrolysis tanks conventionally comprise a steel box inside which is arranged a coating of refractory materials, a cathode of carbon material, crossed by cathode conductors for collecting the electrolysis current at the cathode to conduct it up to cathode outlets passing through the bottom or sides of the box, routing conductors extending substantially horizontally to the next tank from the cathode outlets, an electrolytic bath in which the alumina is dissolved, at least one set anode having at least one anode immersed in said electrolytic bath and an anode rod sealed in the anode, an anode frame to which the anode assembly is suspended via the anode rod, and electrolytic current rise conductors, extending from bottom to top, connected to the routing conductors of the preceding electrolytic cell to convey electrolysis current e from the cathode outlets to the anode frame and the anode assembly and the anode of the next vessel. The anodes are more particularly of anode type precooked with precooked carbon blocks, that is to say cooked before introduction into the electrolytic cell.

The box comprises edges defining an opening through which the anode assemblies are introduced into the electrolytic cell.

To limit thermal losses and avoid the diffusion of gases generated during the reaction electrolysis out of the electrolytic cell, it is intended to close the opening delimited by the box with a set of removable covers resting laterally on the edges of the electrolytic cell and against a superstructure traditionally extending to - above the opening delimited by the box. These covers are generally juxtaposed next to each other, in a longitudinal direction of the electrolytic cell, so as to form a closed chamber.

However, the anode assemblies are consumed during the electrolysis reaction and must therefore be replaced by new anode assemblies. During an anode assembly change, some of the covers are removed to open an access window inside the electrolysis cell.

The spent anode assembly is extracted from the electrolytic cell through this access window and deposited on a support. The extracted used anode assembly is thus temporarily stored on the support before being taken to a revaluation zone.

The crusts formed by the cover products periodically introduced into the electrolytic bath are removed and deposited in a scallop collection device with a cleaning tool also known as a scoop shovel. This tool is inserted into the electrolysis cell through the access window. A new anode assembly is then introduced into the electrolytic cell, via the access window, instead of the spent anode assembly. Finally, the removable covers initially removed are replaced to close the access window. During the time of the change of anode assembly, the access window remains open.

During these steps, the anode devices and assemblies necessary for an anode assembly change, such as the new anode assembly, the spent anode assembly support, and the crust collection device, are temporarily stored near the vessel. electrolysis for which this change of anode assembly is to be realized.

It is known from publication EP0298198 to use an anode storage module hooked on a traveling crane and being inserted into an inter-tank aisle in front of the used anode assembly to be replaced. Such equipment is however complex to implement, use, position and move because of the very small size of the inter-aisles and the large number of interlocking mobile equipment necessary for a change of anode assembly.

Also, given the limited dimensions of inter-tank aisles, which are as narrow as possible to bring the electrolytic cells closer to each other, it is It is customary to store the new and worn anode assemblies and the equipment necessary for an anode assembly change in the operating aisle, near the transverse edges of the chamber of the electrolytic cell.

However, this storage solution clutters the operating aisle. This necessitates the provision of an extended operating aisle, thus an increased structural cost (building, civil engineering, etc.) and / or hinders the movement of vehicles and personnel. The visibility of the staff on foot or the drivers of vehicles can be masked, which imposes additional security measures.

It should also be noted that this storage location is remote from the intervention zone. Indeed, this storage location is located at one end of the electrolysis cell.

The electrolysis service machines, such as a handling bridge, used to move the new and worn anode assemblies, and the devices such as the scoop shovel, thus travel between their storage location at the end of the tank and the intervention area, a significant distance.

In addition, the various successive steps of the anode assembly change process require several round trips between the intervention zone and the operating aisle where the storage location is located. The distance traveled by the electrolysis service machine for a go or a return, and the number of successive round trips, determine the intervention time during which the access window remains open.

However, the longer the access window is open, the more heat losses or gas leaks are important.

This gas pollution, these energy losses and the size of the operating aisle can affect the efficiency of the smelter.

Also, the present invention aims to overcome all or part of these disadvantages by proposing in particular a device for storing a load to limit the size of the operating aisle and to reduce the opening time of a tank electrolysis during an anode assembly change, as well as a method of changing an anode assembly using this storage device.

For this purpose, the subject of the present invention is a device for storing a charge above an electrolytic cell comprising a box, hoods, a cathode and anode assemblies arranged in the box and covered by the covers. , the charge storage device comprising support means, on which is intended to resting the charge to be stored above the electrolytic cell, and support means, designed so that the support means rest stably above the electrolytic cell, in particular above the anode assemblies and hoods.

Thus, the storage device according to the invention allows to provide a temporary storage space above an electrolytic cell, and more particularly above the anode assemblies and covers.

Throughout the description and the claims, the terms "above" an element signify above this element in a volume formed by vertical translation of the surface obtained by projection of this element in a horizontal plane. Since the storage space is above the electrolytic cell, the operating aisle is no longer congested.

In addition, the storage device according to the invention allows positioning closer to the removable hood or covers that will be removed to provide an access window during a tank intervention as a change of anode assembly.

This results in a smaller distance traveled by the electrolysis service machine during this operation and while the access window is open, compared with the state of the art.

This results in a duration of operation, in particular a change of anode assembly, shorter, and an opening time of the access window in the electrolysis cell also shorter.

Thermal losses and gas leaks are limited.

According to a preferred embodiment, the support means comprise one or more support surfaces adapted to support a new anode assembly, a spent anode assembly and / or a crust collecting device formed during an electrolysis reaction.

The charge is therefore more particularly a new anode assembly, a spent anode assembly and / or a crust collecting device formed during an electrolysis reaction.

Thus, the storage device is adapted to be used in the context of an anode assembly change.

Advantageously, the support means comprise means for preventing slippage or falling of the supported load.

Thus, it limits the risks of sliding and accidental fall of the load supported, which could cause significant damage to the electrolytic cell located under the storage device.

Advantageously, the support means comprise an anticorrosion means such as a support or an anticorrosive coating.

Thus, the support means are particularly adapted to receive a spent anode assembly out of the electrolytic bath, and have improved longevity.

According to an advantageous embodiment, the storage device comprises docking means to allow its handling by means of displacement.

Thus, the storage device can be moved to be positioned above the electrolytic cell where a load must be temporarily stored.

The moving means may comprise a handling machine or a handling bridge, generally known as an electrolysis service machine.

The storage device is therefore mobile and easy to use for temporary storage of load associated with a tank operation such as an anode assembly change.

The docking means may be advantageously shaped to allow lifting of the storage device.

The lifting allows not only to position the storage device above the electrolytic cell, to move the storage device along the electrolytic cell to position it closer to the intervention zone, but also possibly to position a storage device above an electrolytic cell adjacent to that where the change of anode assembly is to be made.

According to a preferred embodiment, the support means have a substantially flat plate shape intended to extend in a substantially horizontal plane. Thus, this simple solution makes it possible to quickly deposit a load, without worrying to put it in a precise location. This saves time and therefore reduces the opening time of the electrolytic cell.

Advantageously, the plate has two opposite transverse edges, and the support means extend exclusively from the two transverse edges.

Thus, the support means delimit between them a space that can correspond substantially to the length of the plate.

Advantageously, the support means extend substantially rectilinear and perpendicular to the plate. This ensures a better transmission of the weight of the plate and the load or loads that are put there.

Preferably, the support means comprise an end attached to a lower face of the support means.

This feature offers more robustness to the storage device or, where appropriate, the storage devices.

According to one possibility, the plate has reinforcing means for limiting its flexion under the effect of the weight of a load.

Thus, the support means are more robust and more resistant to bending. This prevents that, due to a large bending, part of the support means comes into contact with covers of the electrolysis tank, which may deform these covers.

Advantageously, the reinforcing means comprise two flanges extending along longitudinal edges of the plate.

Preferably, the support means have a lower face provided with thermal insulation means.

Thus, the support means are deformed less under the effect of the temperature above the electrolytic cell.

According to an advantageous embodiment, the support means comprise two concave housings, integral with the support means, and designed to suspend an anode assembly therein.

Thus, the support means allow to suspend an anode assembly. This has the advantage of being able to move together the storage device and the anode assembly that the storage device supports, with a limited risk of falling.

Advantageously, the storage device comprises spacer means for securing the two concave housings.

This makes the support means more stable.

The invention also relates to a storage system comprising several storage devices having the aforementioned characteristics, distinct and independent, adapted to store, above the electrolytic cell, a new anode assembly, a spent anode assembly and a device for collection of crusts formed during an electrolysis reaction.

This allows an advantageous spatial arrangement, insofar as two separate storage devices can be placed on either side of the access window arranged to replace an anode assembly.

This arrangement therefore provides shorter distances between the intervention zone and the storage space, so that the time required for the change of anode assembly is limited.

According to a preferred embodiment, the storage system comprises three storage devices, including a first storage device for supporting the new anode assembly, a second storage device for supporting the spent anode assembly, and a third device storage device for supporting the crust collecting device.

Thus, the new anode assembly, the spent anode assembly and the scallop collection device each have a dedicated storage device.

This allows an even more advantageous spatial arrangement, since each of these three elements necessary for the anode assembly change can be placed closer to the access window at the time of the anode assembly change.

Indeed, two of the three storage devices can be positioned on either side of this access window, while the remaining storage device can be positioned above an electrolytic cell adjacent to that for which the change of anode assembly must be made, opposite the access window.

In other words, this embodiment allows a staggered or triangular arrangement of the storage devices, so that the time during which the electrolytic cell is open can be substantially reduced.

According to another aspect, the invention also relates to an electrolytic cell comprising a box, hoods, a cathode and anode assemblies arranged inside the box and covered by the covers, and a storage device having the aforementioned characteristics. said storage device extending above the electrolytic cell.

Thus, the electrolytic cell associated with the storage device offers the possibility of storing a charge above the anode assemblies and covers, which limits the bulk around this electrolytic cell.

According to a preferred embodiment, the storage device is disposed above the anode assemblies in place inside the box and the covers arranged above these anode assemblies.

In other words, the storage device is disposed above the producing anode assemblies and closed hoods maintaining a confinement of the gases above them. anode assemblies.

The covers close off an opening in the electrolysis cell through which the anode assemblies are to be placed or extracted inside or outside the box, and the storage device is placed above the covers of the tank. 'electrolysis.

According to a preferred embodiment, the electrolytic cell comprises two opposite longitudinal sides and the storage device extends between the two opposite longitudinal sides.

According to a preferred embodiment, the electrolytic cell comprises a substantially parallelepipedic confinement enclosure placed on the edges of the caisson, the confinement chamber forming a confinement volume within which the anode assemblies are intended to move. during the electrolysis reaction, and the storage device extends between two opposite longitudinal upper edges of the confinement enclosure.

According to a preferred embodiment, the support means are based on the opposite longitudinal upper edges of the confinement enclosure and these edges are advantageously formed by a collection sheath of the tank gases.

This reinforces the mechanical resistance to the load of these edges.

According to a preferred embodiment, the support means comprise bearing surfaces intended to bear against a fixed structure of the electrolytic cell.

In other words, the bearing surfaces advantageously do not bear on the covers of the electrolytic cell.

This advantageously limits the stresses on the hoods in terms of load. Indeed, the supports of the covers are located at their transverse sides, and more particularly at the longitudinal edges of the electrolytic cell, so that they can flex under the effect of the weight of a load. Bending a hood relative to an adjacent hood can create between these two covers an opening that can cause heat losses and gas leaks.

According to a preferred embodiment, the fixed structure comprises reinforcing means designed to allow the fixed structure to support the weight of the storage device and, if appropriate, the load supported by the storage device.

Advantageously, the electrolytic cell comprises at least two counter-support surfaces, on which are intended to rest the bearing surfaces of the storage device, the two counter-support surfaces being arranged on either side of a longitudinal median plane of the electrolysis cell. This feature provides stable support for the storage device.

Preferably, the two abutment surfaces are arranged on longitudinal sides of the electrolysis cell.

Thus, the storage device, where appropriate the storage devices, extend in a transverse direction Y of the electrolytic cell.

According to an advantageous embodiment, the electrolytic cell comprises at least two counter-support surfaces, on which are intended to rest the bearing surfaces of the storage device, and the bearing surfaces and counter surfaces. support comprise interlocking means for cooperating by complementarity of form.

This allows precise positioning of the storage device and prevents slippage of the storage device.

Preferably, the support means extend away from the covers of the electrolytic cell.

The absence of contact between the covers and the support means advantageously avoids that part of the load supported by the support means is transmitted to the covers.

Advantageously, the anode assembly comprises an anode support extending in a transverse direction of the electrolytic cell.

In other words, the anode assembly does not comprise a vertical rod, as in the state of the art, which makes it possible to reduce the height of the anode assembly. This avoids oversizing the storage device, in order to contain costs, and to easily set up this storage device.

According to another aspect of the invention, it relates to an electrolysis plant, in particular an aluminum smelter, comprising a series of electrolysis tanks, including an electrolytic cell and at least one storage device having the aforementioned characteristics, and an operating aisle extending substantially parallel to the series of electrolysis cells.

This electrolysis plant offers a small footprint and a lower operating cost than pre-existing electrolysis plants.

In particular, this electrolysis plant offers shorter distances to travel by electrolysis service machines handling the load, so a significantly shorter opening time when an access window is formed through the covers for access the inside of the electrolysis cell. According to a preferred embodiment, the support means comprise bearing surfaces intended to bear against a surface of an inter-tank aisle along a longitudinal edge of the electrolytic cell and separating said electrolysis cell. an adjacent electrolysis cell.

In other words, the abutment surfaces are located inside inter-tank aisles separating the longitudinal sides of two adjacent electrolysis cells of the series of electrolysis cells. More particularly, the counter-support surfaces of a storage device are located inside two different inter-tank aisles, on either side of the electrolytic cell above which the storage device is disposed.

According to a preferred embodiment, the support means delimit between them a space such that the electrolysis cell extends between the support means of the storage device.

Thus, the storage device spans the electrolytic cell.

According to one embodiment, the electrolysis plant comprises displacement means intended to move the storage device in a substantially longitudinal direction of the electrolytic cell.

According to an advantageous possibility, the moving means comprise a handling machine or a handling bridge for lifting the storage device.

Thus, the same storage device can be used for several electrolysis tanks. In particular, when the electrolysis plant comprises a storage system with several storage devices, one of these storage devices can be arranged on a tank adjacent to the tank where an anode assembly change must take place, precisely in vis-à-vis the part of the tank where the change of anode assembly is to take place.

According to another aspect, the invention also relates to a method of changing a spent anode assembly of an electrolytic cell by a new anode assembly, comprising a step of setting up a storage device having the aforementioned characteristics above the electrolytic cell.

This method makes it possible to reduce the duration of the change of anode assembly, thus the duration during which an access window inside the electrolytic cell is open. This limits thermal losses and gas leaks.

According to an advantageous embodiment, the placing step comprises positioning the storage device in line with one or more anode assemblies close to, advantageously adjacent to, the spent anode assembly. This characteristic makes it possible to minimize the distances traveled by an electrolysis service machine intended to manipulate the elements necessary for the change of anode assembly, among which the spent anode assembly and the new anode assembly.

By the right of an anode assembly is meant in a volume formed by vertical translation of the surface obtained by projection of this anode assembly in a horizontal plane.

The storage device is not positioned at the right of the spent anode assembly to allow extraction from the top of this spent anode assembly, that is to say extraction by substantially vertical upward translation of this spent anode assembly , and to allow a top placement of the new anode assembly, that is to say a placement by substantially vertical downward translation of the new anode assembly.

According to one embodiment, the method is implemented via a storage system comprising a plurality of different storage devices, and the method comprises a step of positioning one of the storage system storage devices in the storage system. above an electrolytic cell adjacent to the electrolytic cell comprising the spent anode assembly.

This feature further decreases the duration of the anode assembly change by allowing a substantially staggered or delta-like arrangement of the storage devices around the spent anode assembly to be replaced.

According to a preferred embodiment, the method comprises the steps of providing an access window between covers of the electrolytic cell to extract the spent anode assembly and replace it with a new anode assembly and to arrange said device for storage vis-à-vis the access window.

In other words, this storage device is arranged substantially symmetrically with the access window with respect to the inter-tank aisle separating the electrolytic cell comprising the spent anode assembly from the electrolysis cell at the same time. above which is positioned this storage device.

This arrangement offers the shortest distance possible between this storage device and the access window.

According to a preferred embodiment, the method comprises a step of providing an access window between the covers of the electrolytic cell to extract the spent anode assembly and replace it with a new anode assembly and the method comprises performing an anode assembly change by means of an electrolysis service machine moving only between transverse sides of the electrolytic cell comprising the spent anode assembly and, if appropriate, a tank of electrolysis adjacent to said electrolytic cell comprising the spent anode assembly, during the entire period during which the access window is formed between the covers of the electrolytic cell to extract the spent anode assembly and replace it by the new anode assembly.

In other words, the electrolysis service machine does not move to the operating aisle along a transverse side of the electrolytic cell throughout this period.

Other features and advantages of the present invention will emerge clearly from the following description of an embodiment, given by way of non-limiting example, with reference to the appended drawings in which:

FIG. 1 is a perspective view of a storage device according to one embodiment of the invention,

FIG. 2 is a sectional view along a longitudinal plane XZ of an electrolytic cell according to one embodiment of the invention,

FIG. 3 is a perspective view of a storage device according to one embodiment of the invention,

FIGS. 4 to 11 are perspective views of an electrolytic cell according to one embodiment of the invention, illustrating the steps of an anode assembly change process according to one embodiment of the invention,

FIGS. 12 and 13 are views from above of a storage device according to one embodiment of the invention, respectively without and with an anode assembly,

Figure 14 is a side view of a storage device according to one embodiment of the invention.

FIG. 1 shows part of an electrolysis plant comprising an electrolysis tank 100 and a storage device 1 according to one embodiment of the invention.

The electrolysis tank 100 is intended for the production of aluminum by electrolysis.

The storage device is for temporarily storing a charge above the electrolytic cell 100.

The electrolysis tank 100 comprises a box 102, covers 120, a cathode 104 and anode assemblies 06 arranged inside the box 102 and covered by the covers. The storage device 1 will be described in more detail below.

The electrolysis tank 100 comprises a fixed structure. The fixed structure comprises the box 102 and, where appropriate, parts of a confinement enclosure 108 intended to confine the tank gases generated during the electrolysis reaction.

The anode assemblies 106 are movable in substantially vertical translation relative to the fixed structure of the electrolytic cell so as to be immersed in an electrolytic bath as and when they are consumed, as can be seen in FIG. 2.

Each anode assembly 106 comprises an anode carrier 12, visible for example in FIG. 13, extending substantially parallel to a transverse direction Y of the electrolytic cell 100.

The electrolysis tank 100 here comprises four sides, two longitudinal sides 114 and two transverse sides 16 opposite two by two, so that the electrolysis tank 100 may have a substantially rectangular shape.

The electrolysis tank 100 defines an opening 18 which is intended for insertion or extraction of the anode assemblies 106 respectively inside or outside the electrolytic cell 100.

It will be noted that the opening 118 is adapted to allow this insertion or extraction by substantially vertical displacement, respectively downward or upward, of the anode assemblies 106.

The containment enclosure 108 may be substantially parallelepipedal and placed on the edges of the box 102, as can be seen in FIG.

The containment enclosure 108 forms a containment volume within which the anode assemblies 106 are intended to move during the electrolysis reaction, as the carbon blocks of the anode assemblies 106 are consumed.

According to the embodiment of FIGS. 1 to 11, the electrolysis tank 100 also comprises a plurality of covers 120.

The covers 120 extend from one longitudinal side 114 to the other of the electrolysis tank 100 to close the opening 118.

The covers 120 are removable to allow to provide through the hood system an access window 124. This access window 124 provides access to the interior of the electrolysis tank 100 for maintenance operations, for example to break or saw crusts formed on the surface of the electrolytic bath during the electrolysis reaction or to replace an anode assembly.

The covers 120 advantageously extend substantially horizontally.

Each cap 120 may extend in one piece from one longitudinal side to the other of the electrolytic cell.

As can be seen in the figures, the storage device 1 extends above the electrolytic cell 100.

As shown in FIG. 2, the storage device 1 is disposed above the anode assemblies 06 in place inside the box. In other words, the storage device 1 is disposed above the anode assemblies 106 in production.

More particularly, the storage device 1 extends between the two opposite longitudinal sides 114 of the electrolytic cell and more specifically between two opposite longitudinal upper edges of the containment enclosure 108.

The storage device 1 rests on the opposite longitudinal upper edges of the containment enclosure 108. The opposite longitudinal upper edges are for example advantageously formed by a vessel gas collection sheath (not shown).

This capture sheath is part of a tank gas collection system that can equip the electrolysis tank 100. This system may comprise a collector, towards which the vat gases are conducted via the capture sheath, and the capture sheath may comprise holes allowing an air communication with the interior of the containment enclosure 108 in order to capture the tank gases.

According to the example of Figures 1 to 1 1, the storage device 1 is more precisely disposed above the covers 120 of the electrolysis tank 100.

Although not shown, the fixed structure may comprise reinforcing means designed to allow the fixed structure to support the weight of the storage device 1 and, if appropriate, the load supported by the storage device 1.

The charge storage device 1 comprises support means, on which is intended to rest the charge to be stored above the electrolytic cell 100, and support means, designed so that the support means rest from stably above the electrolytic cell 100, especially above the anode assemblies 106, opening 118, covers 120 and containment enclosure 108. The support means comprises one or more support surfaces 2 adapted to support a new anode assembly 106a, a spent anode assembly 106b and / or a crust collection device 122 formed during an electrolysis reaction.

The charge intended to be supported by the support means is therefore a new anode assembly 106a, a spent anode assembly 106b and / or a crust collecting device 122 formed during an electrolysis reaction.

The collection device 122 is intended to collect crusts formed by a covering product covering the electrolytic bath of the tank during the electrolysis reaction.

According to the embodiment of Figures 1 to 1 1, the support surface or surfaces 2 are substantially flat.

According to the embodiment of Figures 12 to 14, the support surface 2 or surfaces are curvilinear.

It should be noted that the mass of an anode assembly 106 is of the order of ten to twelve tons. The mass of a crust collecting device 122 can reach 3 to 4 tons. The support means and the support means to which the weight of the support means and the load or loads are transmitted must therefore be able to support these masses.

In addition, the support means and, if appropriate, the support means must be able to withstand the temperatures and the thermal radiation above the electrolytic cell 100, without prejudice to their mechanical properties. In other words, the support means must be able to fulfill their support function, stably, a load weighing several tons despite the temperature above the tank 100 electrolysis.

When one or more covers 120 are removed to provide an access window 124, the temperatures felt one meter above the electrolysis tank 100 may be greater than 400 ° C or more because of the strong radiation electrolytic bath whose temperature is of the order of 1000 ° C.

When the covers 120 are in place, that is to say when these covers 120 close the opening 118, these temperatures can be of the order 100 ° C. Preferably, the support means are positioned above covers 120 which are in place, and offset with respect to hoods 120 removed for the change of anode assembly, so as to allow the withdrawal of the hoods necessary for the change of anode assembly and for the support means to be subjected to little radiation from the electrolytic bath. The support means may include means for preventing slippage or falling of the supported load, such as peripheral rims (not shown). The support surface (s) 2 may advantageously comprise a coating intended to increase the adhesion between the support surface (s) 2 and the supported load.

The support means and / or the support means may further comprise anti-corrosion means. For example, the anti-corrosion means comprise a specific support or coating adapted to withstand the attack of liquids of the electrolytic bath that can flow from the spent anode 106b assembly and the temperature evolved by the spent anode 106b assembly. The support means may in particular comprise a containment box inside which the spent anode assembly is stored for confining the gases emitted by the spent anode assembly during its cooling.

The storage device 1 comprises docking means for handling by means of displacement.

The moving means may comprise a handling machine or a handling bridge (not shown), generally known as an electrolysis service machine.

The docking means may be advantageously shaped to allow lifting of the storage device 1. For example, the docking means comprise hooks (not shown) positioned at the periphery of the storage device 1. This ensures the stability of the load once raised.

According to the embodiment of Figures 1 to 1 1, the support means have a substantially flat plate form 4, intended to extend in a substantially horizontal plane.

The plate 4 has in particular two opposite transverse edges 6. The support means advantageously extend exclusively from the two transverse edges 6.

The plate 4 may have reinforcing means for limiting its flexion under the effect of the weight of a load. The reinforcing means comprise, for example, two flanges 8 extending along the longitudinal edges of the plate 4.

The plate 4 may have a substantially rectangular shape.

The support means comprise bearing surfaces and connecting members connecting the bearing surfaces and the support means, the connecting members being able to correspond for example to the support legs, as shown in Figure 1.

The connecting members 12 extend here substantially rectilinear and perpendicular to the plate 4. In addition, the connecting members 12 may comprise an end attached to a lower face 14 of the support means, including the plate.

The support means have a lower face 14 which can be provided with thermal insulation means, such as a coating of thermally insulating material.

According to the embodiment of FIGS. 12 to 14, the support means comprise two concave housings 16 secured to support means and designed to suspend an anode assembly 106 therefrom. In particular, the housings 16 are designed to receive and support the anodic support 112.

The support means comprise, according to the example of Figure 12 and 13, two opposite walls 18 from each of which projects one of the recesses 16.

The concave dwellings are opposite.

Still according to the embodiment illustrated in FIGS. 12 and 13, the storage device 1 comprises spacer means for making the two opposite walls 18 and the two concave housings 16 integral. The spacer means comprise, for example, walls or connecting arms intended to extend in a transverse direction X of the electrolytic cell 100.

According to the example of FIG. 14, the support means may comprise two independent assemblies, that is to say that can be moved independently of one another, each comprising a support surface 22 on a structure fixed electrolysis tank 100, as the box 102, and one or more support legs 24 connecting the support surface 22 to the support means. Both sets are on two opposite sides of the electrolytic cell 100.

The invention also relates to a storage system comprising several storage devices 1 having the aforementioned characteristics, distinct and independent. The storage system is adapted to store, above the electrolytic cell 100, a new anode assembly 106a, a spent anode assembly 106b and a crust collection device 122 formed during an electrolysis reaction.

This allows an advantageous spatial arrangement, insofar as two separate storage devices 1 can be placed on either side of the access window arranged to replace an anode assembly, as can be seen for example in FIG. . Advantageously, the storage system comprises three storage devices 1, including a first storage device 1a for supporting the new anode assembly 106a, a second storage device 1b for supporting the spent anode assembly 106b, and a third device 1c storage for supporting the device 122 for collecting crusts.

This allows a staggered or triangular arrangement of the storage devices 1a, 1b, 1c, as can be seen in FIG. 3, so that the duration during which an access window is open in the electrolytic cell 100 for achieve an overall change of anode can be significantly reduced.

The storage system can be adapted to simultaneously support the new anode assembly, the spent anode assembly and the crust collection device. This limits the organizational constraints of an overall anode change.

The support means advantageously comprise bearing surfaces 22 intended to bear against a fixed structure of the electrolytic cell 100. In other words, the bearing surfaces 22 do not advantageously bear on caps 120. The bearing surfaces 22 are for example intended to rest on a substantially flat surface.

The electrolysis tank 100 comprises at least two counter-support surfaces (not shown) on which the bearing surfaces 22 are designed to rest. The two abutment surfaces are arranged on either side of a longitudinal median plane of the electrolytic cell 100, that is to say a plane substantially perpendicular to the transverse direction Y of the tank 100. electrolysis and separating this tank into two similar halves.

The electrolytic cell can be equipped with the storage system described above. The two abutment surfaces are arranged on either side of the opening 118.

The abutment surfaces may preferably be a part of the upper belt of the box 102 or a collection sheath forming a belt in the upper part of the containment enclosure 108.

The abutment surfaces are preferably arranged on the longitudinal sides 114 of the electrolytic cell 100.

Although this is not shown, the bearing surfaces 22 and the abutment surfaces may advantageously comprise interlocking means intended to cooperate by complementary shape. The interlocking means comprise by example lugs intended to be inserted into housing of complementary shape.

As can be seen for example in FIG. 2, the support means extend away from the hoods 120.

The invention also relates to the electrolysis plant, in particular an aluminum smelter, comprising a series of electrolysis tanks, including the electrolysis tank 100. The electrolysis plant according to the invention also comprises an operating aisle 1001 extending substantially parallel to the series of electrolytic cells, that is to say in a manner substantially perpendicular to the tank 100 d. electrolysis, and a storage device 1 described above.

The electrolysis tanks are intended to be traversed by an electrolysis current of up to several hundreds of thousands of amperes. The electrolysis tanks may be arranged transversely with respect to the direction of the line or the series, that is to say substantially perpendicularly to the overall flow direction of the electrolysis current at the scale of the line or line. series.

The bearing surfaces 22 may, if appropriate, be in abutment against a surface of an inter-tank aisle 1002 along a longitudinal edge of the electrolytic cell 100 and separating the electrolytic cell 100 from an electrolytic cell. adjacent. In other words, the abutment surfaces are located inside inter-tank aisles separating the longitudinal sides of two adjacent electrolysis cells of the series of electrolysis cells.

The bearing surfaces 22 may for example be supported on a tiling or on gratings, reinforced, of the aisle 1002 between vats.

The fact of placing the storage devices on inter-tank aisle surfaces instead of the fixed structure of the electrolysis cell lies in the fact that the maneuver of putting them in place requires less precision, so is more simple and faster to implement. This helps to reduce the duration of an intervention, so the opening time of the electrolytic tank 100.

Again, the support surfaces 22 and the abutment surfaces may comprise interlocking means intended to cooperate by complementary shape, such as those described above.

It will be noted that the support means advantageously delimit between them a space such that the electrolysis tank 100 extends between the support means. Thus, each storage device 1 spans the electrolysis tank 100, as can be seen in FIG. 1 or 3. In particular, the support means, in particular the connecting members 12, may be spaced a distance greater than the width of the electrolytic cell 100.

Furthermore, the support means, in particular the connecting members 12, may extend over a height at least greater than the height of the electrolytic cell 100.

The electrolysis plant further comprises displacement means for moving the storage device 1 above the electrolytic cell in a substantially longitudinal direction X of the electrolytic cell 100. The displacement means comprise a handling machine intended to lift the storage device 1.

The invention also relates to a method of changing an anode assembly 106b used an electrolytic cell, in particular the electrolytic cell 100 described above, by a new anode assembly 106a.

This method comprises a step of setting up a storage device 1 previously described above the electrolytic cell, as can be seen in FIG. 4.

The implementation step comprises positioning the storage device 1 in the right of one or more anode assemblies close to, advantageously adjacent to the spent anode assembly 106b, as can be seen in FIG. 2.

The storage device 1 is not positioned at the right of the spent anode assembly to allow displacement of the covers 120 to open an access door, to allow extraction from the top of this spent anode assembly, it is that is to say extraction by substantially vertical upward translation of this spent anode assembly, and to allow the top of the new anode assembly to be put in place, that is to say a placement by substantially vertical downward translation. of the new anode set.

The method is implemented by means of a storage system comprising several separate storage devices 1, and the method comprises a step of positioning one of the storage devices 1 over a tank 101. electrolysis adjacent to the electrolytic cell 100 comprising the spent anode assembly, as illustrated in FIG. 3. This storage device 1 is arranged opposite a window 124 with controlled access or shortly arranged between hoods 120 to extract the spent anode 106b assembly and replace it with the new anode assembly 106a. This storage device 1 can therefore be arranged substantially symmetrically to the access window 124 with respect to the inter-tank aisle 1002 separating the electrolysis tank 100 comprising the spent anode assembly from the electrolysis tank 101. above which is positioned this storage device 1. The anode assembly change is advantageously carried out by means of an electrolysis service machine moving only between transverse sides 116 of the electrolysis tank 100 comprising the spent anode assembly and, if appropriate, a tank 101. electrolysis unit adjacent to the electrolytic cell 100 comprising the spent anode assembly, during the entire period during which the access window 124 is formed between the covers 124.

The method may also include all or some of the following steps:

a step of removing one or more covers 120 to provide an access window 124 through which the used anode assembly 106b and the new anode assembly 106a are extracted, for example by means of a service machine electrolysis,

a step of breaking or sawing the crusts formed on the surface of an electrolytic bath,

a step of removing the spent anode 106b assembly to place it on the second storage device 1b (FIGS. 5 and 6),

a step of cleaning the crusts by means of a tool such as a shovel 130 with crusts (FIG. 7),

a crust collecting step by deposition of these crusts in the collection device 122 positioned where appropriate on the third storage device 1c, a step of removing the new anode assembly 106a from the first storage device 1a (FIG. 9) and a step of placing the new anode assembly 106a inside the electrolytic cell 100 (FIG. 10),

a step of closing the access window 124 by repositioning the hood or caps 120 initially removed.

The three storage devices 1a, 1b, 1c can then be moved and positioned above another tank, for example adjacent as visible in Figure 1 1.

Of course, the invention is not limited to the embodiment described above, this embodiment having been given as an example. Modifications are possible, particularly from the point of view of the constitution of the various elements or by the substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

A device (1) for storing a charge over an electrolytic cell (100) comprising a box (102), covers (120), a cathode (104) and anode assemblies (106). arranged in the box (102) and covered by the covers (120), the charge storage device (1) comprising support means, on which is intended to rest the charge to be stored above the tank (100) electrolysis method, and support means, designed for the support means to rest stably above the electrolytic cell (100), in particular above the anode assemblies (106) and the covers (120). ).

Storage device (1) according to claim 1, characterized in that the support means comprise one or more support surfaces (2) adapted to support a new anode assembly (106a), a spent anode assembly (106b), and or a device (122) for collecting crusts formed during an electrolysis reaction.

3. Device (1) for storage according to claim 1 or 2, characterized in that the storage device (1) comprises docking means to allow its handling by means of displacement.

4. Device (1) for storage according to one of claims 1 to 3, characterized in that the support means have a substantially planar plate (4), intended to extend in a substantially horizontal plane.

5. Device (1) for storage according to claim 4, characterized in that the plate (4) has reinforcing means for limiting its flexion under the effect of the weight of a load.

6. Device (1) for storage according to one of claims 1 to 5, characterized in that the support means comprise two recesses (16) concave, secured to the support means, and designed to suspend an anode assembly.

7. Storage system comprising several storage devices (1) according to one of claims 1 to 6, separate and independent, adapted to store, above the tank (100) of electrolysis, an assembly (106a) anodic nine, a spent anode assembly (106b) and a crust collecting device (122) formed during an electrolysis reaction.

8. Storage system according to claim 7, characterized in that the storage system comprises three storage devices (1), including a first storage device (1a) for supporting the new anode assembly (106a), a second storage device (1b) for supporting the spent anode assembly (106b), and a third storage device (1c) for supporting the crust collecting device (122).

Electrolytic cell (100) comprising a box (102), covers (120), a cathode (104) and anode assemblies (106) arranged inside the box (102) and covered by the covers ( 120), and a storage device (1) according to one of claims 1 to 6, said storage device (1) extending above the electrolysis tank (100).

10. Electrolytic cell (100) and storage device (1) according to claim 9, characterized in that the storage device (1) is disposed above the anode assemblies (106) in place inside the box (102) and covers (120) covering these anode assemblies (106).

1 1. electrolysis tank (100) and storage device (1) according to claim 9 or 10, characterized in that the electrolysis cell (100) comprises two opposite longitudinal sides (114) and the storage device ( 1) extends between the two opposite longitudinal sides (114) of the electrolytic cell (100).

12. Electrolytic cell (100) and storage device (1) according to one of claims 9 to 11, characterized in that the electrolytic cell (100) comprises a chamber (108) substantially parallelepiped confinement on the edges of the box (102), the confinement chamber (108) forming a containment volume within which the anode assemblies (106) are intended to move during the electrolysis reaction, and the device (1) storage extends between two opposite longitudinal upper edges of the enclosure (108) confinement.

13. Electrolytic cell (100) and storage device (1) according to claim 12, characterized in that the support means rest on the opposite longitudinal upper edges of the enclosure (108) for confinement and these edges are formed by a collection sheath of the tank gases.

14. Electrolysis tank (100) and storage device (1) according to one of claims 9 to 13, characterized in that the support means of the storage device (1) comprise surfaces (22) of support intended to bear against a fixed structure of the tank (100) electrolysis.

15. Electrolytic cell (100) and storage device (1) according to claim 14, characterized in that the fixed structure comprises reinforcing means designed to allow the fixed structure to support the weight of the device (1). storage and if necessary the load supported by the device (1) storage.

16. Electrolytic cell (100) and storage device (1) according to claim 14 or 15, characterized in that the electrolysis cell (100) comprises at least two counter-support surfaces, on which are intended to resting the bearing surfaces of the storage device (1), and in that the bearing surfaces (22) and the abutment surfaces comprise interlocking means intended to cooperate in complementary form.

17. Electrolysis plant, in particular an aluminum smelter, comprising a series of electrolytic cells, including an electrolytic cell (100) and at least one storage device (1) according to one of claims 9 to 16, and an operating aisle (1001) extending substantially parallel to the series of electrolysis cells.

18. Electrolysis plant according to claim 17, characterized in that the support means comprise bearing surfaces (22) intended to bear against a surface of an inter-tank aisle (1002) along an edge. (1 14) longitudinal of the electrolytic cell (100) and separating said electrolytic cell (100) from an adjacent electrolytic cell (101).

19. Electrolysis plant according to claim 17 or 18, characterized in that the support means delimit between them a space such that the electrolysis tank (100) extends between the support means of the device (1). ) storage.

20. Electrolysis plant according to one of claims 17 to 19, characterized in that the electrolysis plant comprises displacement means for moving the storage device (1) in a substantially longitudinal direction of the vessel. (100) electrolysis.

21. Electrolysis plant according to claim 20, characterized in that the moving means comprise a handling machine or a handling bridge for lifting the storage device (1).

22. A method of changing a spent anode assembly of an electrolytic cell (100) with a new anode assembly (106a), comprising a step of placing a Storage device (1) according to one of Claims 1 to 6 above the electrolytic cell (100).

23. The method of claim 22, characterized in that the implementation step comprises the positioning of the storage device (1) to the right of one or more sets (106) anode close to the assembly (106b) anodic worn.

24. The method of claim 22 or 23, characterized in that the method is implemented through a storage system according to one of claims 7 or 8, and the method comprises a step of positioning the one of the storage system storage devices (1) above an electrolytic cell (101) adjacent to the electrolytic cell (100) comprising the spent anode assembly (106b).

25. The method of claim 24, characterized in that the method comprises the steps of providing a window (124) for access between covers (120) of the electrolytic cell (100) to extract the assembly (106b). ) anode and replace it with a new anode assembly (106a) and arrange said storage device (1) vis-à-vis the access window.

26. Method according to one of claims 22 to 25, characterized in that the method comprises a step of providing an access window (124) between covers (120) of the tank (100) electrolysis to extract the spent anode assembly (106b) and replace it with a new anode assembly, and that the method comprises performing an anode assembly change by means of an electrolysis service machine moving only between sides (116) transverse electrolytic cell (100) comprising the spent anode assembly (106b) and optionally an electrolytic cell (101) adjacent to said electrolytic cell (100) comprising the assembly (106b) during the period during which the access window (124) is formed between the covers (120) of the electrolytic cell (100) to extract the spent anode assembly (106b) and replace it with the new anode assembly (106a).