Method of starting up an electrolytic cell for aluminum production

Abstract

The technology relates to means for providing a more homogenous temperature distribution across a cathode during a start-up procedure and more particularly during a dry start-up procedure of an electrolytic cell for aluminum production. The technology entails the mitigation of leakage of electrical current that may occur, under certain star-up circumstances, in an electrolytic cell. This may be accomplished by hindering transfer of moisture to the solid electrolyte material inside the pot of the cell from at least one humid component of the electrolytic cell. The technology includes a method of lining the pot of the electrolytic cell with a barrier material at locations that may be subject to electrical leakage through the solid electrolyte material.

Description

METHOD OF STARTING UP AN ELECTROLYTIC CELL FOR ALUMINUM PRODUCTIONTECHNICAL FIELD

[0001] The technical field relates to the start-up of electrolytic cells for producing aluminum, whether starting up an electrolytic cell which has never been in operation or which has been shut down.BACKGROUND

[0002] During operation of an electrolytic cell for aluminum production, the cathode block of the cell deteriorates and eventually needs to be replaced. This is a normal occurrence which will typically take place over the course of several years of operation.

[0003] Prior to placing an electrolytic cell into operation, the cathode block must be preheated, typically to a temperature of from about 800 to 900°C. This may be done in various ways, including for example, applying a granular conductive material like coke or graphite on the top surface of the cathode beneath the anodes and applying power to the anodes to thereby transmit electrical current to the cathode block. The granular conductive material applied between the cathode and the anodes is often referred to as a contact resistance material. Coke or graphite may be selected to obtain the desired electrical resistance of a contact material so as to deliver more or less heat to the electrolytic cell.

[0004] In U.S. patent no. 7,485,215, a process is described in which the periphery of the electrolytic cell is filled with crushed electrolyte bath material and sodium carbonate. In addition, rock wool is applied against the upper surface and the outer surfaces of the anodes as well as over the central corridor of the electrolytic cell in order to minimize heat losses from the electrolytic cell during pre-heating of the cathode block. The electrolytic cell is then energized so as to cause an electric current to flow between the anodes and the cathode block.

[0005] Once the cathode is pre-heated, an amount of molten bath is taken from other operational, so-called donor cells, and is added to the electrolytic cell for immersing the anodes. The anodes may then be raised away from the cathode block to their operational positions without creating any open electrical circuits. The molten electrolyte bath becomes the conductor material between the anode and the cathode and finally, after that heat-up phase is complete, molten aluminum metal is added to coverthe top surface of the cathode block surface beneath the molten electrolyte bath. At this stage, a solid crust is formed on top of the bath and the anodes may becovered with the usual additions of alumina, solid granulated bath, and additives such as AIF3 and calcium to thermally isolate the cell. Normal operation can begin with an optimal heat balance of the cell giving the opportunity to reduce energy input.

[0006] In such a traditional cell start-up, five to twelve tons of molten electrolyte bath from about ten donor cells are required, depending on the size of the electrolytic cell. This is a very labor-intensive operation which not only is time consuming but also monopolizes use of the crane of the smelter to siphon and transport molten electrolyte bath from donor cells to the start-up cell. This can be a problem in a smelter where the same crane is also needed to siphon metal and for regular anode changing operations. In addition to the labor involved with liquid bath transportation, more care is required to maintain the donor cells in operation. In addition, cell start-up by way of donor cells is not always an option, for example in new smelters where donor cells are unavailable at least until some electrolytic cells are first put into operation.

[0007] It is also known to start-up a new cell by applying a layer of dry cryolite to the upper surface of the cathode block around the anodes up to a certain height, in order to insulate the area surrounding the anodes and to direct the heat generated in the contact resistance material toward the cathode block. While these known start-up procedures have various benefits, there is still room in the art for improvement.SUMMARY

[0008] In accordance with one general aspect of the present disclosure, there is provided a method of starting up an electrolytic cell for aluminum production, the electrolytic cell comprising a cathode block, a peripheral joint surrounding the cathode block, and an internal liner surrounding the peripheral joint, the cathode block and the peripheral joint defining a bottom of a pot of the electrolytic cell, the internal liner defining sides of the pot, the method comprising: lining the pot with a barrier, the lining of the pot including lining at least a portion of the peripheral joint with the barrier; lowering an anode of the electrolytic cell inside the pot toward the cathode block until the anode is operatively connected to the cathode block; adding solid electrolyte material inside the pot; delivering electrical current from the anode to the cathode block to pre-heat the cathode block; and raising the anode away from the cathode block.

[0009] In accordance with another aspect, there is provided a method of mitigating leakage of electrical current in an electrolytic cell for aluminum production, the electrolytic cell comprising a cathode block having an outer perimeter and a contact area raised from the cathode block at alocation spaced from the outer perimeter, the cathode block defining a bottom of a pot of the electrolytic cell, the method comprising: lowering an anode of the electrolytic cell inside the pot onto the contact area; adding solid electrolyte material at the bottom of the pot alongside the anode; delivering the electrical current from the anode to the cathode block via the contact area; and hindering transfer of moisture to the solid electrolyte material inside the pot from at least one humid component of the electrolytic cell defining a portion of the pot located outside of the outer perimeter.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Reference is now made to the accompanying figures in which:

[0011] Fig. 1 is a cross-sectional, front side view of an electrolytic cell;

[0012] Fig. 2 is a top, planar view of the electrolytic cell of Fig. 1 ;

[0013] Fig. 3 is a flowchart showing steps for starting-up the electrolytic cell of Fig. 1 according to embodiments;

[0014] Fig. 4 is a cross-sectional, front side view of the electrolytic cell of Fig. 1 shown with a layer of electrolyte material therein;

[0015] Fig. 5 is a cross-sectional, front side view of the electrolytic cell of Fig. 1 shown with the electrolyte material covering an upper surface of the anodes;

[0016] Fig. 6 is a perspective view of a portion of a pot of the electrolytic cell of Fig. 1 , shown with a barrier lining the pot;

[0017] Fig. 7A is a graph showing temperatures recorded overtime at discrete locations of a cathode block of a first electrolytic cell having a pot that is not lined with a barrier;

[0018] Fig. 7B is a graph showing temperatures recorded overtime at discrete locations of a cathode block of a second electrolytic cell having a pot that is lined with a barrier;

[0019] Fig. 8A is a perspective view of a horizontal barrier piece of the barrier of Fig. 6;

[0020] Fig. 8B is a perspective view of a side barrier piece of the barrier of Fig. 6;

[0021] Fig. 8C is a perspective view of a corner barrier piece of the barrier of Fig. 6;

[0022] Fig. 8D is a perspective view of an overlapping barrier piece of the barrier of Fig. 6;

[0023] Fig. 9 is a top, planar view of the pot of Fig. 6, shown lined with horizontal barrier pieces;

[0024] Fig. 10 is a top, planar view of a portion of the pot of Fig. 6, shown lined with side barrier pieces;

[0025] Fig. 11 is a cross-sectional, front side view of the portion of the pot of Fig. 10, shown with the side barrier pieces held by holding members;

[0026] Fig. 12 is a top, planar view of a portion of the pot of Fig. 6, shown with spacers;

[0027] Fig. 13 is a top, planar view of the portion of the pot of Fig. 12, shown with side barrier pieces disposed over the spacers;

[0028] Fig. 14 is a perspective view of the portion of the pot of Fig. 13, shown with a spacer defining a vent; and

[0029] Fig. 15 is a flowchart showing steps for starting-up the electrolytic cell of Fig. 1 according to an embodiment.

[0030] It will be noted that throughout the appended drawings, like features are identified by like reference numerals.DETAILED DESCRIPTION

[0031] One aspect of at least some embodiments of the present technology generally relates to means for providing a more homogenous temperature distribution across a cathode during a start-up procedure, such as a dry start-up procedure of an electrolytic cell for aluminum production. Another aspect of some embodiments relates to the mitigation of leakage of electrical current that may occur, under certain star-up circumstances, in an electrolytic cell. A further aspect of some embodiments relates to the management of vapor release from humid components (e.g., concrete components inside the outer shell of the cell) during the start-up procedure and, more particularly, with the channeling or deflection of the vapor away from predetermined cell zones so as to foster a more heterogeneous cathode temperature distribution. General structural characteristics and principles of operation of an electrolytic cell will now be described.

[0032] Thus, referring to the drawings and, more particularly, to Figs. 1 and 2, in accordance with the present technology, there is provided an electrolytic cell 10 for aluminum production. The cell 10 includes an outer shell 22 having a plurality of walls 22a, 22b defining a rectangular perimeter. Namely, the outer shell 22 has a pair of shorter, transversely extending (i.e., along axis X) walls 22a (Fig. 2) at opposite ends of the cell 10, and a pair of longer, longitudinally extending (i.e., along axis Y) walls 22b on opposite sides of the cell 10, that together circumscribe an interior of the outer shell 22. The walls 22a, 22b may respectively be referred to as transverse walls 22a and longitudinal walls 22b, or as end walls 22a and side walls 22b. Generally, the outer shell 22 is made of metal such as steel.

[0033] Inside the outer shell 22, the cell 10 is provided with an internal liner 24 and a cathode block 26 recessed depthwise (i.e., along axis Z) in the internal liner 24. The internal liner 24 and the cathode block 26 together define a hollow pot P of the cell 10. Namely, the cathode block 26 has an upper cathode surface 26u defining a bottom of the pot P, and the internal liner 24 includes blocks 28 that surround the upper cathode surface 26u and extend upwardly therefrom. The blocks 28 each have an outer lateral side 28o facing toward a proximate one of the walls 22a, 22b of the outer shell 22, and an inner lateral side 28i defining an interior perimeter of the pot P, thus forming sides of the interior of the pot P. The blocks 28 may thus be referred to as side blocks 28. Such side blocks 28 may be referred to as transverse blocks 28a, longitudinal blocks 28b or corner blocks 28c depending on whether they are located alongside a transverse wall 22a, alongside a longitudinal wall 22b or at a junction therebetween. The internal liner 24 also typically includes blocks of refractory material 24c disposed underneath the cathode block 26 and / or the side blocks 28. In some embodiments, the internal liner 24 may include a layer of suitable material disposed between at least some of the blocks 28 and their most proximate wall 22a, 22b of the outer shell 22.

[0034] The cathode block 26 is typically constructed of carbonaceous material(s) and may be referred to as a carbothermic cathode block. Typically, and as best seen in Fig. 2, the cathode block 26 is formed of a plurality of cathode block portions 26’ suitably disposed relative to one another.

[0035] The side blocks 28 are typically pre-formed and constructed of carbonaceous material. Each wall 22a, 22b of the outer shell 22 is typically lined with a plurality of side blocks 28 that are disposed next to one another.

[0036] Spaces / joints between consecutive components of the cell 10 defining the pot P, e.g., between a cathode block portion 26’ and a side block 28, between two cathode block portions 26’, and in some cases between two side blocks 28, are typically filled by refractory material R. Such refractory material R is selected so as to be suitable for resisting to thermal and / or chemical attack by molten aluminum and molten electrolyte. According to some embodiments, the refractory materials R consists of carbonaceous materials, which may be provided in the form of paste or mortar, for example. The refractory material forming the joints and the refractory material entering in the composition of the liner 24 (e.g., the concrete joining the bricks 24c) may have a water / humidity content that may be released while the refractory materials heat up during the start-up procedure of the cell. As will be seen hereinafter, the channeling or diversion of the vapor released from such “wet” components away from the predetermined cell zones may provide for a more uniform temperature distribution at the surface of the cathode 26 during the start-up procedure.

[0037] The spaces filled by refractory material R may be referred to as joints extending longitudinally alongside the cathode block portions 26’. Such joints include three different types of joints, namely transverse peripheral joints JPT, longitudinal peripheral joints JPL and transverse internal joints JIT. The transverse peripheral joints JPT (or end joints) have a width defined between a given transverse block 28a and a transverse side of its adjacent cathode block portion 26’. The longitudinal peripheral joints JPL (or side joints) have a width defined between a given longitudinal block 28b and a longitudinal side of its adjacent cathode block portion 26’. The transverse and longitudinal peripheral joints JPT, JPL form a peripheral joint JPT, JPL circumscribing an outer perimeter of the cathode block 26. The transverse internal joints JIT have a width defined between mutually facing sides of any two adjacent cathode block portions 26’. In the depicted embodiment, the only internal joints provided are transverse internal joints JIT, as the cathode block portions 26’ extend transversely from one longitudinal peripheral joint JPL to the opposite one. It is contemplated however that cathode blocks 26 may be provided with different arrangements of cathode block portions 26’ requiring other types of internal joints (e.g., longitudinal internal joint(s)).

[0038] The joints JPT, JPL, JIT may be said to be part of the internal liner 24. The internal liner 24 may also be referred to as a lining system designed both for defining the pot P inside which the aluminum production process is to occur, and for providing an adequate thermal balance for the operation of the cell 10. Solidified electrolyte matter (schematically shown at S in Fig. 1) whichmay accumulate over the course of the operation of the cell 10, may also be said to form part of the internal liner 24.

[0039] The cell 10 also includes a superstructure supporting an anode frame (not shown) and a series of anodes 30 (which is also referred to as an anode 30) suspended to the anode frame above the pot P. The anodes 30 each include an anode block 32 attached to the frame by a suitable means, in this case via an array of pin-like members 34 embedded in the block 32 and an anode stem 36 which is held proximate to the frame.

[0040] The anode blocks 32 have an upper surface 32u and an opposed lower surface 32I (or contact surface). The anode frame is adapted to lower or raise the anode blocks 32 within the pot P of the cell 10. The anodes 30 are in this case of the pre-baked type, and its blocks 32 are made of carbonaceous material.

[0041] The pot P is sized and arranged relative to the anodes 30 such that anode blocks 32 are receivable thereby proximate to the cathode block 26 while leaving sufficient residual space inside the pot P to accommodate the substances required to conduct the electrolysis process, e.g., alumina and electrolyte(s). As shown in Fig. 2, this residual space corresponds to transverse corridors defined either between a transverse block 28a and an adjacent anode block 32 (i.e., a transverse peripheral corridor CPT), or between two longitudinally consecutive anode blocks 32 (i.e., a transverse internal corridor CIT), and to longitudinal corridors defined either between a longitudinal block 28b and an adjacent anode block 32 (i.e., a longitudinal peripheral corridor CPL), or between two transversely consecutive anode blocks 32 (i.e., a longitudinal internal corridor CIL).

[0042] Either for pre-heating the cell 10 or during electrolysis, an electrical current flows to and from the cell 10, as schematically shown at F, arriving from one side of the cell 10 and leaving from an opposite side of the cell 10 respectively referred to as an upstream side 10u and a downstream side 10d. The electrical current enters the cell 10 through the anodes 30 via the superstructure, the anode frame, the anode stems 36, the attachment means 34 and the anode blocks 32. The electrical current then enters the cathode block 26 and is carried out of the cell 10 away from the downstream side 10d by current collector bars 40 and eventually by suitable electrical conductors 42.

[0043] At the onset of a start-up procedure, the cell 10 must be pre-heated. For the purposes of pre-heating the cell 10, granular contact resistance material 50 may be provided on the upper surface 26u of the cathode block 26 at suitable locations. Such contact material 50 isthus raised relative to the upper surface 26u. Stated otherwise, the contact material 50 projects vertically from the cathode block 26. By way of example, graphite and / or coke can be used as contact material 50. Exemplary characteristics of suitable contact material are provided in international patent application number PCT / CA2012 / 000474, incorporated herein by reference. Depending on the implementation, the contact material 50 can define discrete contact areas 50 of different sizes and shapes, and in some cases form pattern(s) of contact areas 50. Furthermore, the number of contact areas 50 can vary. It is contemplated that in some implementations, the contact material 50 may be placed on the cathode block 26 before the cathode block 26 is installed in the cell 10. In some such implementations, the contact material 50 is integral to the cathode block 26, and the contact material 50 can correspond to projections defined by the upper surface 26u.

[0044] The contact material 50 is disposed so as to underlie the lower surfaces 32I of the anodes 30 such that it may make widespread, intimate contact therewith upon the anodes 30 being suitably lowered until abutting the contact material 50. The anodes 30 may be said to at least indirectly abut the cathode block 26, depending on whether the contact material 50 is deemed to be part of the cathode block 26 or distinct therefrom. In the depicted embodiment, two contact areas 50 are provided for each anode 30. Then, upon the cell 10 being energized, electric current may flow from the anodes 30 to the cathode block 26 through the contact material 50.

[0045] Referring now to Fig. 3, there is shown a method 100 of starting up an electrolysis cell referred to as a dry start-up procedure. This procedure is characterized as “dry” as it involves the use of solid electrolyte material as opposed to solely using molten electrolyte bath obtained from donor cells.

[0046] In some embodiments, the method 100 includes a step 1 10 of applying contact material 50 on the upper surface 26u of the cathode block 26. In some embodiments, the contact material 50 may already be present, such that step 110 may be omitted. In step 120, the method 100 includes lowering the anodes 30 onto the contact material 50 as described above.

[0047] Then, in step 130, a suitable molten electrolyte bath is established in the pot P before the anodes 30 can be raised away from the cathode block 26. At least some of the molten electrolyte bath or pool is obtained from electrolyte material being in a solid state while it is added to the pot P. Hence, step 130 includes a step 132 of adding solid electrolyte material in the pot P of the cell 10. The solid electrolyte material, which can include cryolite (Na3AIF6), crushed solid electrolyte bath material previously recovered from another cell already in operation, and anysuitable additives such as AIF3 is applied around the anode blocks 32 and over the upper surface 26u of the cathode block 26. Exemplary characteristics of suitable solid electrolyte material are provided in international patent application number PCT / CA2012 / 000474. As shown in Fig. 4, in embodiments, an initial amount, or first layer 70, of solid electrolyte material generally surrounds the anode blocks 32 but generally remains clear of the vertical spaces between the lower surfaces 32I of the anode blocks 30 and the upper surface 26u of the cathode block 26. Stated otherwise, the first layer 70 is mostly provided along the corridors CPT, CPL, CIT, CIL (Fig. 2).

[0048] Step 130 also includes a step 134 of pre-heating the cathode block 26, during which the cell 10 is energized. The cathode block 26 and the contact material 50 offer resistance to the current delivered from the anodes 30, and are thus heated as they convert some of the electrical current into thermal energy. The solid electrolyte material present close to the cathode block 26, if any, heats up as it receives heat from the cathode block 26.

[0049] In embodiments, addition of electrolyte material in the pot P is carried out iteratively, for example once every hour. As shown at 136, the height of electrolyte material inside the pot P may be monitored so that the electrolyte material may be added up to a certain height above the cathode block 26, for example one at which the entire height of the anode blocks 32 is covered. As shown in Fig. 5, electrolyte material may be added such that the total amount extends up to or above the upper surface 32u of the anode blocks 32, which may mitigate undesired heat losses and solidification of molten electrolyte material. A depth of the electrolyte material may vary depending on the embodiment.

[0050] As solid electrolyte material heats up, some of it melts at the bottom of the pot P whereas a crust usually forms on top of the molten electrolyte. Additional solid electrolyte material may be added by breaking this crust and by pushing the additional solid electrolyte material into the underlying molten electrolyte.

[0051] The depth of molten electrolyte material above the cathode block 26 may be monitored as shown at 138 so that the molten electrolyte material may accrue up to a suitable depth, which may be predetermined. In embodiments, for an electrolytic cell having typical dimensions, the suitable depth of molten electrolyte material is of at least about 30 centimeters (11 .81 inches) above the cathode block 26. The depth of the molten material can be measured periodically, for example every two to three hours during the start-up procedure. Various alternatives for carrying out step 130 are possible.

[0052] When a suitable molten electrolyte bath is obtained as described above, the anodes 30 may be raised as shown in step 140. The anodes 30 are raised gradually until the lower contact surfaces 32I of the anode blocks 32 reach a suitable distance, which may be predetermined, relative to the upper surface 26u of the cathode block 26. Subsequently, as shown in step 150, alumina may be added into the pot P, for example to control anode effects. Depending on the implementation, the alumina may be added between 2 to 5 hours after raising the anodes 30.

[0053] In step 160, molten metal may be added into the pot P, for example to stabilize the cell 10 and / or to avoid over-heating. In step 170, the distance separating the anode b l o c k s 32 from the molten metal surface may be adjusted to stabilize the cell 10. Then, as shown at step 180, the cell 10 can be operated in a normal manner to produce aluminum by electrolysis.

[0054] In developing the present technology, certain electrical, thermal and mechanical phenomena occurring in the cell 10 during the start-up procedure have been discovered and studied. For instance, as the cell 10 is energized during a start-up procedure, at least some of the components defining the pot P of the cell 10 heat up and may be said to bake. Indeed, whether a cell 10 undergoes its first start-up or is being restarted after refurbishment, at least some components of the pot P, referred to henceforth as humid components, contain some degree of moisture. For example, components constructed of refractory material R (Figs. 1 and 2), such as the peripheral joint JPT, JPL, or any concrete components (e.g., the bricks 24c) lining the interior of the outer shell 22 may constitute humid components. As these humid components heat up, they exude an amount of water, mainly in the form of vapor, some of which ends up inside the pot P. If electrolyte material 70 is present inside the pot P as vapor emerges therein, the electrolyte material 70 may humidify and be rendered conductive, at least locally, allowing some leakage of electrical current to occur from the anodes 30 to the electrolyte material 70. In some applications, the solid electrolyte material 70 may to some extent be conductor even without the addition of vapor from the humid components. Some of the electrical current may thus flow from the anodes 30 to the cathode block 26 via the electrolyte material 70, thus bypassing the contact material 50. Such electrical leakage has been found to be undesirable, as it promotes heterogeneous heat transfers and / or heat generation in the cathode block 26 which, in turn, renders the cathode block 26 prone to deterioration.

[0055] The present technology provides a method 200 (Fig. 3) of lining the pot P with a barrier 80 (Fig. 6) such that, at least in some implementations, occurrences of electrical leakage and / or bypass of the contact material 50 are limited or prevented. Exemplary results of a particularimplementation of this method 200 will now be briefly discussed with reference to Figs. 7A and 7B. Two generally identical cells were provided, mutatis mutandis, and respectively subjected to a start-up procedure 100 (Fig. 3), during which the temperature (C) of their cathode blocks 26 was monitored over time (hours) at several corresponding locations CPI-CPS spaced along the peripheral corridors CPT, CPL. The second cell , whose recorded temperature over time is shown in Fig. 7B, was subjected to the method 200 (Fig. 3) of lining its pot P with a suitable implementation of the barrier 80, whereas the first cell (whose recorded temperature over time is shown in Fig. 7A) was not lined with any barrier 80. By comparing Figs. 7A and 7B, it shall be noted that the recorded temperatures and the rates at which they vary overtime are closer among the monitored locations CPI-CPS of the lined second cell than they are on the unlined first cell, especially during the first 20 hours of the start-up procedure 100.

[0056] As shown in Fig. 3, this method 200 of lining the pot P of the cell 10 may be considered as additional steps of the method 100 of starting up a cell 10. This method 200 is generally intended to be performed prior to the addition of solid electrolyte material in the pot P (e.g., step 132), at least at location(s) which are to be lined with such barrier 80. For safety purposes, this method 200 is intended to be performed prior to the pre-heating of the cathode block 26 (e.g., step 134).

[0057] The barrier 80 will now be generally described with reference to Figs. 8A-14. The barrier 80 is constructed of one or more material(s) suitable for resisting or retarding diffusion of moisture therethrough, at least under certain circumstances. Stated otherwise, at least some of the material(s) out of which the barrier 80 is constructed, impart the barrier 80 with a low permeability. According to some embodiments, the barrier 80 is configured to act as a vapor deflector to channel / redirect the vapor away from the predetermined electrolyte zones (e.g., joints that are covered with the electrolyte material). As will be seen hereinafter, according to some embodiments, the barrier 80 is configured to cover zones where humidity is susceptible to be released from humid cell components into the electrolyte material. In some embodiments, the material(s) may have a low electric conductivity and, thus, act as an electrical insulator in addition to a vapor barrier / deflector. Non-limiting examples of suitable materials for constructing the barrier 80 include cardboard, agglomerated paper, wood, gypsum, plastics, polymers and polyimide film, among others. At least in some embodiments, the material(s) of the barrier 80 are thermally consumable, such that the barrier 80 significantly degrades, dissolves and / or is consumed while submerged by molten electrolyte bath over the course of the start-up procedure. In some embodiments, the material(s) are selected such that at the end of the start-up procedure, the typeand amount of any residual material(s) of the barrier 80 is not deemed a significant source of contamination of either the molten electrolyte bath or the molten metal. In the depicted embodiment, the barrier 80 is generally made of cardboard. The cardboard may be of the corrugated type, thereby preventing the inner and outer layers of the cardboard to be simultaneously soaked. Other types of materials may be structured so as to provide interior cavities.

[0058] Although the barrier 80 may be provided as an integral piece in some embodiments, the barrier 80 is more conveniently provided as a plurality of barrier pieces 82, 84, 86, 88 sized and arranged relative to one another and relative to the internal liner 24 so as to form the barrier 80. Examples of such barrier pieces 82, 84, 86, 88 are shown in Figs. 8A-8D. The shapes and sizes contemplated for each of the barrier pieces 82, 84, 86, 88 are vast. Depending on the implementation, any barrier piece 82, 84, 86, 88 may adopt a shape suitable for covering any locations from the pot to the electrolyte material contained therein. For instance, the barrier pieces may adopt a shape suitable for lining a selected portion of the pot P that is susceptible to otherwise be in contact with the solid electrolyte material.

[0059] For instance, the barrier 80 may include horizontal barrier piece(s) 82 (as seen for example in Figs. 8A and 9) intended to be laid horizontally at the bottom of the pot P. For example, one type of horizontal barrier piece 82 may be provided to line either one of the joints JPT, JPL, JIT. According to some embodiments, such horizontal barrier piece 82 may thus have a first dimension, in this case a width 82w defined between opposite edges 82a, 82b of the horizontal barrier piece 82, that is at least equal to the effective width of the electrolyte material in contact with the cathode 26, between the anodes 32 and above the joints JPT, JPL, JIT. The width 82w of the barrier piece 82 is selected to extend beyond the opposed lateral sides of the associated joint so as to project underneath any anode blocks bordering the joint (i.e. the width of the barrier piece is greater than that of the joint it is covering). The overlapping relationship between the anode blocks 32 and the horizontal barrier pieces 82 can for instance be seen in Fig. 9. In this manner, the horizontal barrier piece 82 can sufficiently cover the joint JPT, JPL, JIT SO as to hinder diffusion of vapor from the joint JPT, JPL, JIT to electrolyte material 70 deposited thereabove. As mentioned above, according to at least some embodiments, the width 82w of the horizontal barrier piece 82 is greater than that of the corresponding joint JPT, JPL, JIT, such that the horizontal barrier piece 82 may extend across the entire width of the corresponding joint JPT, JPL, JIT and overhang the adjacent anode blocks and the adjacent components of the internal liner 24. Sizing the horizontal barrier piece 82 as such may, at least under certain circumstances, hinder diffusion of vapor fromthe joint JPT, JPL, JIT to electrolyte material deposited on top of an adjacent cathode block portion 26’. Such sizing of the width 82w may also allow for slight misalignment of the horizontal barrier piece 82 with respect to the joint JPT, JPL, JIT. AS seen in Fig. 9, the width 82w may be sized such that it is equal to or less than a transverse distance T between the contact material 50 of two adjacent cathode block portions 26’.

[0060] A second dimension of the horizontal barrier piece 82 perpendicular to the first dimension, in this case a length 82I defined between opposed edges 82c, 82d of the horizontal barrier piece 82, may vary depending on the implementation. The length 82I may for example correspond to a length of a side of a cathode block portion 26’, or even to that of a side of the entire cathode block 26. In the depicted embodiment, two horizontal barrier pieces 82 are provided for each transverse internal joint JIT. Each piece 82 of a given pair extends from adjacent to a respective one of the longitudinal peripheral joint JPL toward, albeit short of, the center of the transverse internal joint JIT. In this manner, a gap G is defined between the pieces 82 of a given pair, leaving a portion of the transverse internal joint JIT potentially exposed to electrolyte material at the center of the joint JIT. According to one aspect, the gap G may promote electrolyte contact with cathode (heat transfer, bath generation). According to another aspect, such a gap G may be desirable whenever liquid electrolyte may need to be added. The gap G also avoid using barrier material in zones less susceptible to current leakage or zones where there might be less vapor release. A third dimension of the horizontal barrier piece 82 orthogonal to the first and second dimensions, in this case a thickness 82t, may for example be smaller than the width 82w and the length 82I. In embodiments, the thickness 82t may be smaller than the thickness of the contact material 50. By sizing the thickness 82t as such, the horizontal barrier piece 82 would not hinder abutment of the anode blocks 82 onto the contact material 50 when the anodes 30 are lowered. In some embodiments, the horizontal barrier piece 82 is compressible to some degree, such that it may be sized thickerthan the contact material 50 and compress as an anode block 32 is lowered thereagainst until the anode block 32 abuts the contact material 50. Referring to Fig. 8A, in some embodiments, the thickness 82t may be generally even across the length 82I and width 82w. In some embodiments, the thickness 82t of the horizontal barrier pieces 82 may vary. For example, a given horizontal barrier piece 82 may define a flat portion 82’ having the thickness 82t, and one or more raised portions that protrude from the flat portion 82’, thereby defining portions of the horizontal barrier piece 82 that are thicker than the thickness 82t. The raised portions can for example be referred to as locators or anchors L, i.e., structures of the horizontal barrier piece 82 that may be used to maintain the barrier piece 82 in a predetermined position after the anode blocks 32 have been lowered. For example, two locators / anchors L may be provided on eachhorizontal barrier piece 82. In some embodiments, the locator(s) / anchor(s) L may be sized so as to fill a vertical space between an anode block 32 and the underlying flat portion 82’ upon the anode block 32 being in contact with the contact material 50. This may assist in constraining the flat portion 82’ against the bottom of the pot P, e.g., the transverse internal joint JIT and cathode block 26, which may contribute to the performance of the barrier 80 by avoiding displacement when placing others barrier pieces or pouring solid electrolyte material into the pot P. In some embodiments, the locators / anchors L may be spaced lengthwise from one another, such that they may be respectively aligned with a longitudinal peripheral corridor CPL and a longitudinal internal corridor CIL (Fig. 2) upon the corresponding flat portion 82’ being laid against a transverse internal joint JIT. Hence, a distance between the locators L may be equal to or greater than a width of an anode block 32. The locators / anchors L may for example be elongated cylinders that extend across the entire width 82w, although various other shapes and sizes are contemplated. Locator(s) / anchors L may be integral to their corresponding flat portion 82’ or may be separate structures joined thereto. The material(s) of which corresponding locators / anchors L and flat portion 82’ are constructed may be the same or may be different.

[0061] In the depicted embodiment, the internal joints JIT are provided with internal barrier pieces 82, whereas the peripheral joints JPT, JPL are provided with so-called peripheral barrier pieces 84, 86, 88, i.e., pieces that are intended to cover the peripheral joints JPT, JPL. The peripheral barrier pieces 82, 84, 86, 88 may be configured to provide horizontal and vertical protection, to avoid shortage between 1) the anode and the cathode, 2) the anode and the joint, and 3) the anode and the side block. Each peripheral barrier piece 84, 86, 88 has a bottom edge 84b, 86b, 88b intended to be disposed proximate to the bottom of the pot P, and an upper edge 84u, 86u, 88u spaced away from the bottom edge 84b, 86b, 88b and intended to be disposed at a certain height relative to the bottom of the pot P, for example at or proximate to a top edge of the side blocks 28. In some embodiments, the side blocks 28 may be humid components. The vertical barrier pieces 84, 86, 88 may in such cases hinder diffusion of vapor from the side blocks 28 to adjacent solid electrolyte material, and thus limit or prevent electrical leakage and / or bypass of the contact material 50.

[0062] Depending on the embodiment, the peripheral barrier pieces 84, 86, 88 may be shaped so as to follow a profile of their corresponding side block 28. For example, peripheral barrier pieces 84 intended for lining the transverse blocks 28a and the longitudinal blocks 28b, i.e., side barrier pieces 84 (as seen for example in Figs. 8B and 10-14), may have a sloped portion 84’ having the bottom edge 84b and extending upwardly at an angle to a horizontal portion 84”, fromwhich a terminal vertical portion 84”’ having the upper edge 84u extends. Peripheral barrier pieces 86 intended for lining the corner blocks 28c, i.e., corner barrier pieces 86 (as seen for example in Figs. 8C and 12-14), may have a sloped portion 86’ having the bottom and upper edges 86b, 86u and that extends therebetween. Peripheral barrier pieces 88 intended to cover joints, or gaps, between two consecutive peripheral barrier pieces 84, 86, i.e., overlapping barrier pieces 88, may have a sloped portion 88’ having the bottom edge 88b and extending upwardly at an angle to a horizontal portion 84” having the upper edge 88u. Examples of such overlapping barrier pieces 88 are shown in Figs. 8D, 13 and 14.

[0063] Depending on the embodiment, the peripheral barrier pieces 84, 86, 88 may have a horizontal portion 84h, 86h, 88h alongside the sloping portion 84’, 86’, 88’ that has a size suitable for covering an adjacent peripheral joint JPT, JPL and / or for overlapping an end 82c, 82d of an adjacent horizontal barrier piece 82. The horizontal portion 84h, 86h, 88h respectively have opposite distal and proximal edges 84a 84b, 86a, 86b, and 88a, 88b, defining a width 84w, 86w, 88w, and opposite ends 84c 84d, 86c, 86d, and 88c, 88d defining a length 84I, 86I, 88I, and a thickness 84t, 86t, 88t. The widths 84w, 86w, 88w, lengths 84I, 86I, 88I and thicknesses 84t, 86t, 88t may be sized differently or similarly to those of the horizontal barrier pieces 82, mutatis mutandis. The width 84w, 86w, 88w of a given horizontal portion 84h, 86h, 88h may for example be greater than the width of an adjacent portion of the peripheral joint JPT, JPL, such that the horizontal portion 84h, 86h, 88h overhangs the cathode block 26 and / or extends to under the anode block 32. The corresponding distal edge 84a, 86a, 88a may for example be located near the contact material 50. Thus, one or more of the horizontal portions 84h, 86h, 88h may be sized so as to cover a portion of the cathode block 26, for example the portion of the cathode block 26 extending from the peripheral joint JPT, JPL to the contact material 50.

[0064] In other embodiments, the peripheral joints JPT, JPL may be covered wit barrier pieces similar to the above described barrier pieces 82. In some such embodiments, at least some of the peripheral barrier pieces 84, 86, 88 are not provided with a respective horizontal portion 84h, 86h, 88h. In other such embodiments, the vertical barrier pieces 84, 86, 88 may be omitted.

[0065] Assembly characteristics of the barrier 80 will now be described with regard to Figs. 8A to 14. In some embodiments, the barrier 80 is provided with spacer(s) 90 (Figs. 8D, 12 and 14) intended to be disposed between a portion of the internal liner 24 and a portion of the barrier 80 following this portion of the internal liner 24 such that the barrier 80 is locally offset relative to the internal liner 24, defining a hollow, elongated passage between the internal liner 24 and the barrier 80 henceforth referred to as a vent V (Figs. 6, 13, 14).

[0066] In some embodiments, the spacer(s) 90 can be integral to the barrier 80. For example, depending on the embodiment, a spacer 90 may be provided in the form of a continuous ridge projecting from a surface of a given barrier piece 82, 84, 86, 88, or in the form of a plurality of projections spaced along the surface so as to define a flow path of the corresponding vent V. In some embodiments, the spacer(s) 90 are instead provided as distinct pieces, for example in the form of one or more beam-like or cord-like members of suitable size and shape for defining the vent V upon being placed between the internal liner 24 and the barrier 80 where venting is desired. Depending on the implementation, the spacers) 90 can be attached to either one or both of the internal liner 24 and the barrier 80, or merely inserted therebetween after the barrier 80 has been laid onto the internal liner 24.

[0067] The vent(s) V may desirably route vapor away from humid components of the internal liner 24 toward the exterior of the pot P while avoiding contact with the solid electrolyte material 70. Vent(s) V may be disposed wherever suitable along the barrier 80, for example alongside one or more side blocks 28 and / or alongside one or more of the joints JPT, JPL, JIT. A peripheral vent V may be provided in communication with the peripheral joint JPT, JPL. AS shown for example in Fig. 13, the vent V may include a horizontal vent portion Vh extending alongside the peripheral joint JPT, JPL, and a vertical vent portion Vv extending from the horizontal vent portion Vh alongside the internal liner 24. In some embodiments, the horizontal vent portion Vh includes a first horizontal vent portion Vh extending to the vertical vent portion Vv in a first direction, and a second horizontal vent portion Vh extending to the vertical vent portion Vv in a second direction opposite to the first direction.

[0068] Junctions between any two adjacent barrier pieces 82, 84, 86, 88 may be provided in a variety of ways. For instance, adjacent barrier pieces 82, 84, 86, 88 may overlap one another. Adjacent barrier pieces 82, 84, 86, 88 may otherwise be disposed next to one another, with or without a gap being defined therebetween. In embodiments, an adhesive material A (Fig. 14) may be used to join adjacent barrier pieces 82, 84, 86, 88 to one another. The adhesive material may in some cases be suitable for resisting or retarding diffusion of moisture therethrough, at least under certain circumstances, and may thus be said to form part of the barrier 80.

[0069] Various means are contemplated for holding the barrier 80 in place relative to the pot P. For example, adhesive material may be used to locally join the barrier 80 (or a barrier piece 82, 84, 86, 88) to the underlying internal liner 24 and / or cathode block 26. Holding member(s) H may also be used to locally hold the barrier 80 against the internal liner 24 at least by extending from a surface of neighboring anode block 32 toward the internal liner 24, leaving enough spacebetween a given holding member H and the internal liner 24 to accommodate the thickness of the barrier 80. Stated otherwise, the holding member(s) H can be used to hold the barrier 80 away from the anode blocks 32. The holding member(s) H can have a beam-like, elongated shape, whereby a length thereof, defined between the anode block 32 and the internal liner 24, is its largest dimension. Such sizing of the holding member(s) H may desirably minimize the volume it occupies inside the pot P at the expense of electrolyte material 70. The holding member(s) H may be constructed of various materials, for example one or more of the materials contemplated for the barrier 80. Thus, at least in some embodiments, the material(s) of the holding member(s) H are thermally consumable. In some embodiments, the holding member(s) H and the barrier 80 are constructed of different materials. In the depicted embodiment, the holding members H are constructed of a first material, in this case wood, whereas the components of the barrier 80 held by the holding members H are constructed of a second, more flexible, material, in this case cardboard. The relative flexibility of the barrier 80 may thus assist in conforming the barrier 80 to a shape of the pot P, whereas the relative rigidity of the holding members H may assist in subsequently maintaining the barrier 80 in the requisite shape relative to the pot P.

[0070] Referring to Figs. 3 and 15, exemplary implementations of the method 100 of starting up a cell 10 including lining the inside of the pot P with a barrier consistently with the above will now be generally described. The method 100 generally includes step(s) of lining the pot P with a barrier such as the barrier 80 described hereinabove (e.g., the method 200). The method 100 also generally includes a step of lowering the anodes 30 of the cell 10 inside the pot P toward the cathode block 26 until the anodes 30 at least indirectly abut the cathode block 26, for example as shown at 120. The method 100 also generally includes a step of establishing a suitable molten electrolyte bath inside the pot P (e.g., step 130), which includes steps of adding solid electrolyte material inside the pot P (e.g., step 132) and of delivering electrical current from the anodes 30 to the cathode block 26 to pre-heat the cathode block 26 (e.g., step 134) as previously described. The method 100 also generally includes raising the anodes 30 away from the cathode block 26. In some implementations, the method 100 includes applying contact material 50 on the cathode block 26 (e.g., step 110) prior to lowering the anodes 30.

[0071] The lining of the pot P includes lining at least a portion of the peripheral joint JPT, JPL with the barrier 80. According to some embodiments, lining the pot P includes lining the portions of the cathode 26, side blocks 28a, 28b in contact with the solid electrolyte material nearthe joints. Lining the pot P may also include using the barrier pieces to cover any other known vapor exit locations. The portion(s) of the peripheral joint JPT, JPL may correspond to portion(s) adjoiningcorresponding portion(s) of the cathode block 26 located in the peripheral corridors CPT, CPL, for example at one or more of the locations CPI-CPS. Thus, in some embodiments, the barrier 80 is applied at least at discrete locations along the peripheral joint JPT, JPL. In other embodiments, the lining of the pot P with the barrier 80 includes covering all of the peripheral joint JPT, JPL with the barrier 80. In some embodiments, the lining of the peripheral joint JPT, JPL, whether in full or in part, includes overlapping the cathode block 26 and the internal liner 24. Stated otherwise, the barrier 80 extends peripherally along at least a portion of the peripheral joint JPT, JPL and transversely thereto so as to overhang both the cathode block 26 and the internal liner 24.

[0072] In some embodiments, the lining of the peripheral joint JPT, JPL, whether in full or in part, is performed after lowering the anodes 30. Indeed, the barrier 80 (or pieces thereof) can be slid into the pot P and onto the peripheral joint JPT, JPL via the peripheral corridor CPT, CPL.

[0073] In some embodiments, the lining of the pot P with the barrier 80 is performed before the adding of the solid electrolyte material inside the pot P. This can assist in preventing the inadvertent deposition of solid electrolyte material on a portion of the pot P intended to be lined with the barrier 80 before the lining, which could present a risk of electrical current bypass despite the presence of the barrier 80.

[0074] In some embodiments, the lining of the pot P with the barrier 80 is performed before delivering the electrical current from the anodes 30 to the cathode block 26. In other words, the intervention of placing the barrier 80 inside the pot P may conveniently and safely be done while no electrical current is delivered to the cathode block 26, for example prior to the pre-heating of the cathode block 26.

[0075] In some embodiments, the lining of the pot P with the barrier 80 includes adjoining barrier pieces (for example the barrier pieces 82, 84, 86, 88) to one another inside the pot P to form the barrier 80. This may help conforming the shape of the barrier 80 to the shapes of the various surfaces of the pot P, and to ensure adequate coverage of the portions of the pot P intended to be lined. As the need arises, the relative positions of the barrier pieces 82, 84, 86, 88 can be discretely adjusted before they are fixed in place.

[0076] In some embodiments, the lining of the pot P with the barrier 80 includes joining the barrier 80 to one or more of the internal liner 24 and the cathode block 26.

[0077] In some embodiments, the lining of the pot P with the barrier 80 includes conforming a shape of the barrier 80 to a shape of the pot P before lining the pot P therewith. Indeed, the barrier 80 (or individual barrier pieces 82, 84, 86, 88) may be flexible such that they may bedeformable to adopt a shape of the pot P, for example a profile of a side block 28. In other embodiments, the barrier 80 (or individual barrier pieces 82, 84, 86, 88) may be pre-formed so as to readily conform to the portion of the pot P to be lined therewith.

[0078] In some embodiments, the lining of the pot P with the barrier 80 includes lining at least a portion of an internal joint (e.g., the transverse internal joint JIT) of the cell 10 defined between two adjacent cathode block portions 26’ of the cathode block 26. In some embodiments, the lining of the pot P with the barrier includes covering the internal joint, portions of the cathode in contact with the solid electrolyte material adjacent to the joint or other locations where vapor may be released from a humid components inside the cell.

[0079] In some such embodiments, the lining of the internal joint JIT can be performed before lowering the anodes 30. This may particularly be appropriate if the internal joint JIT extends beneath an anode 30, i.e., does not align with a transverse internal corridor CIT.

[0080] In some such embodiments, the lining of the internal joint JIT includes separately lining two portions of the internal joint JIT that are spaced from one another so as to define a gap G between the portions of the internal joint JIT.

[0081] In some embodiments, the method 100 further comprises defining at least one vent V between the barrier 80 and the pot P upon lining the pot P with the barrier 80. Stated otherwise, some embodiments of the method 100 may be said to include as step of defining a flow path from underneath the barrier 80 to a location spaced vertically away from the cathode block 26, in region(s) of the pot P deemed suitable for evacuating vapor from humid components while limiting undesirable electric current leakage and / or bypass. According to some embodiments, vents can be provided at locations where important quantities of vapor are likely to wet the electrolyte material.

[0082] In some embodiments, the method 100 comprises disposing at least one spacer 90 alongside the barrier 80 or the pot P such that upon lining the pot P with the barrier 80 and the spacer 90 being suitably placed, the at least one spacer 90 spaces the barrier 80 from the pot P to define the vent V.

[0083] Depending on the embodiment, the disposing of the spacer 90 may be performed before lining the pot P with the barrier 80 (e.g., the spacers 90 of Fig. 12 disposed horizontally alongside or near the side blocks 28 to define horizontal vent portions Vh) or after lining the pot P with the barrier 80 (e.g., the spacer 90 of Fig. 14 disposed vertically alongside a side block 28to define a vertical vent portion Vv). According to some embodiments, the spacer is disposed on the joint at the side block base.

[0084] In some embodiments, the lining of the pot P with the barrier includes disposing at least one horizontal barrier piece (whether a discrete horizontal barrier piece 82 or the horizontal portion 84h, 86h, 88h of a barrier piece 84, 86, 88) inside the pot P such that it extends at least partially between the cathode block 26 and an anode block 32. In some such embodiments, such horizontal barrier piece(s) are clear of the contact material 50 so that they do not hinder contact of the anode blocks 32 therewith. In some such embodiments, such horizontal barrier pieces have a thickness that is less than that of the contact material 50.

[0085] In view of the foregoing, it shall be apparent that multiple variations are contemplated as to the order in which steps of the method 100 are to be performed. An exemplary implementation of the method 100, or arrangement of steps, will now be described with regard to Figs. 9-15. In this embodiment, at the onset of the method 100, the anodes 30 are raised or absent, and the contact material 50 is already present on the cathode block 26.

[0086] The method comprises, in step 202, lining the internal joints JIT with barrier pieces. As shown for example in Fig. 9, each internal joint JIT that may be in contact with the solid electrolyte material may be lined with two horizontal barrier pieces 82. Alternatively, all internal joints may be lined (i.e. not only the ones that are in contact with the solid electrolyte material). The horizontal barrier pieces 82 may each extend from an outer end located near a respective longitudinal peripheral corridor CPL, to an inner end located near a centerline of the cathode block 26, or longitudinal internal corridor CIL of the pot P. The inner ends may be spaced apart so as to define a gap G. Each horizontal barrier piece 82 may overhang both cathode block portions 26’ adjacent to its corresponding internal joint JIT, yet remains clear of the contact material 50 of either cathode block portion 26’. Then, the anodes 30 are lowered onto the contact material 50 (step 120). After the anodes 30 are lowered, the method 100 comprises the lining of the peripheral joint, the creation of vents V and the holding of the barrier 80 relative to the internal liner 24 as described with respect to steps 204 to 208. Unless specified otherwise, the sequence in which these steps are performed can vary depending on the implementation.

[0087] The method comprises, in step 204, disposing spacers 90 along the peripheral joint JPT, JPL, at locations where horizontal vent portions Vh are desired. As shown for example in Fig. 12, spacers 90 may be disposed alongside the transverse peripheral joints JPT.

[0088] The method comprises, in step 206, lining at least a portion of the peripheral joint JPT, JPL with peripheral barrier pieces 84, 86, 88. As shown for example in Fig. 10, each longitudinal peripheral joint JPL and adjacent longitudinal block 28b is lined with at least one side barrier piece 84, where no spacer 90 is present. As shown for example in Fig. 13, each transverse peripheral joint JPT and adjacent transverse block 28a are lined with at least one side barrier piece 84. In this case, alongside each transverse peripheral joint JPT, two side barrier pieces 84 are disposed over the spacers 90 so as to define horizontal vent portions Vh. Also, the two side barrier pieces 84 are spaced from one another so as to define a gap. An overlapping barrier piece 88 is disposed such that it extends across the gap and overlaps the two spaced-apart ends of the side barrier pieces 84 so as to define a vertical vent portion Vv. As best seen in Fig. 14, a spacer 90 can be provided between the overlapping barrier piece 88 and the adjacent longitudinal block 28a to increase a depth of the vertical vent portion Vv, which may desirably promote venting of the underlying peripheral joint JPT, JPL. Adhesive material A, such as tape, can be used to hold each side of the overlapping barrier piece 88 in place relative to its adjacent side barrier piece 84. As shown for example in Figs. 12 and 13, each junction of the peripheral joint JPT, JPL, i.e., each junction between consecutive transverse and longitudinal peripheral joints JPT, JPL, and their adjacent corner blocks 28c are lined with a corner barrier piece 86. Each corner barrier piece 86 may be disposed so as to overlap its adjacent side barrier piece 84.

[0089] The method 100 also comprises, in step 208, holding at least some of the vertical barrier piece(s) 84, 86, 88 against their respective adjacent side block(s) 28, in this case via holding member(s) H (Figs. 11 , 13, 14). Stated otherwise, the method 100 may provide for disposing, at location(s) inside the pot P where the barrier 80 requires holding against the interior liner 24, a holding member H so as to fill the resulting space between an anode block 32 and the barrier 80 upon the barrier 80 being laid against the interior liner 24.

[0090] As shown in Fig. 15, some of the above-mentioned steps can be performed iteratively and / or in alternate sequences. For example, some lining of the peripheral joint JPT, JPL (step 206) may in some cases occur before any spacers 90 are disposed along the peripheral joint JPT, JPL (step 204). Also, some barrier pieces 84, 86, 88 may be held against adjacent side blocks 28 (step 208) before all of the spacers 90 have been installed (step 204) and / or before all of the barrier pieces 84, 86, 88 have been installed (step 206).

[0091] Once the barrier 80 is suitably disposed with respect to the peripheral joint JPT, JPL, the method 100 then continues with step 130 in which a suitable molten electrolyte bath is established inside the pot P. It is contemplated however that in some implementations, solid electrolytematerial 70 may be added into the pot P before the completion of steps 204-208, for example a region of the pot P where the barrier 80 is already suitably disposed. In some such implementations, the distribution and weight of the solid electrolyte material 70 may suffice to hold the barrier 80 in place, such that step 208 may be omitted, at least with respect to a portion of the barrier 80. The method 100 then continues as shown in Fig. 3 with steps 140, 150, 160 and 170 leading up to the production of aluminum (step 180).

[0092] In view of the above, it shall be appreciated that some of the embodiments of the present technology provide a method of mitigating leakage of electrical current in an electrolytic cell 10 for aluminum production, namely electrical current that would bypass the contact area(s) 50 provided atop the cathode block 26. Such method may for example comprise lowering an anode 30 of the electrolytic cell 10 inside the pot P onto the contact area 50, adding solid electrolyte material at the bottom of the pot P up to alongside the anode 30, delivering electrical current from the anode 30 to the cathode block 26 via the contact area 50, and hindering transfer of moisture to the solid electrolyte material inside the pot P from at least one humid component of the electrolytic cell 10 that defines a portion of the pot P located outside of the outer perimeter of the cathode block 26. As discussed hereinabove, the hindering of moisture transfer may be accomplished by providing a suitable barrier 80 that lines the humid component and potentially the area therearound. This barrier 80 can be constructed of cardboard, among other contemplated materials. The humid component can for instance be a peripheral joint JPT, JPL that surrounds the outer perimeter of the cathode block 26 at the bottom of the pot P. The barrier 80, or at least pieces thereof, can extend horizontally across the peripheral joint JPT, JPL. The barrier 80 can in some embodiments extend horizontally to over the cathode block 26, for example to a location between the cathode block 26 and the anode 30. The barrier 80 can in some embodiments extend vertically from the peripheral joint JPT, JPL to alongside the anode 30. In some such embodiments, the barrier 80 espouses the shapes of the side blocks 28 of the cell 10.

[0093] Several alternative embodiments and examples of the present technology have been described and illustrated herein. The embodiments of the present technology are intended to be exemplary only. A person of ordinary skill in the art would appreciate the features of the individual embodiments, and the possible combinations and variations of the components. A person of ordinary skill in the art would further appreciate that any of the embodiments could be provided in any combination with the other embodiments disclosed herein. It is understood that the present technology may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be consideredin all respects as illustrative and not restrictive, and the present technology is not to be limited to the details given herein. Accordingly, while the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the present technology. The scope of the present technology is therefore intended to be limited solely by the scope of the appended claims.

Claims

CLAIMS:1 . A method of starting up an electrolytic cell for aluminum production, the electrolytic cell comprising a cathode block, a peripheral joint surrounding the cathode block, and an internal liner surrounding the peripheral joint, the cathode block and the peripheral joint defining a bottom of a pot of the electrolytic cell, the internal liner defining sides of the pot, the method comprising: lining the pot with a barrier, the lining of the pot including lining at least a portion of the peripheral joint with the barrier; lowering an anode of the electrolytic cell inside the pot toward the cathode block until the anode is operatively connected to the cathode block; adding solid electrolyte material inside the pot; delivering electrical current from the anode to the cathode block to pre-heat the cathode block; and raising the anode away from the cathode block.

2. The method of claim 1 , wherein the lining of the at least the portion of the peripheral joint with the barrier includes extending the barrier from over the cathode block to alongside the internal liner.

3. The method of claim 1 , wherein the lining of the pot with the barrier includes covering all of the peripheral joint with the barrier.

4. The method of claim 1 , wherein the lining of the pot with the barrier is performed before adding of the solid electrolyte material inside the pot.

5. The method of claim 1 , wherein the lining of the pot with the barrier is performed before delivering the electrical current from the anode to the cathode block.

6. The method of claim 1 , wherein the lining of the pot with the barrier includes adjoining barrier pieces inside the pot to form the barrier.

7. The method of claim 1 , wherein the lining of the pot with the barrier includes joining the barrier to one or more of the internal liner and the cathode block.

8. The method of claim 1 , further comprising conforming a shape of the barrier to a shape of the pot before lining the pot with the barrier.

9. The method of claim 1 , wherein the lining of the pot with the barrier includes lining at least a portion of an internal joint of the electrolytic cell defined between two adjacent cathode block portions of the cathode block.

10. The method of claim 9, wherein the lining of at least the portion of the internal joint is performed before lowering the anode.1 1 . The method of claim 9, wherein the lining of at least the portion ofthe internal joint includes separately lining two portions ofthe internal joint that are spaced from one another so as to define a gap between the portions of the internal joint.

12. The method of claim 1 , further comprising defining a vent between the barrier and the pot upon lining the pot with the barrier, the vent defining a flow path from underneath the barrier to a location spaced vertically away from the cathode block.

13. The method of claim 12, wherein the vent includes a horizontal vent portion extending alongside the peripheral joint, and a vertical vent portion extending from the horizontal vent portion alongside the internal liner.

14. The method of claim 13, wherein the horizontal vent portion is a first horizontal vent portion extending toward the vertical vent portion in a first direction, the vent including a second horizontal vent portion extending toward the vertical vent portion in a second direction opposite to the first direction.

15. The method of claim 12, further comprising disposing at least one spacer alongside the barrier or the pot such that the at least one spacer spaces the barrier from the pot to define the vent upon lining the pot with the barrier.

16. The method of claim 15, wherein the disposing of the at least one spacer is performed before the lining of the pot with the barrier.

17. The method of claim 1 , wherein the lining of the pot with the barrier includes disposing at least one horizontal barrier piece inside the pot such that it extends at least partially between the cathode block and the anode.

18. The method of claim 17, wherein the lowering of the anode includes indirectly abutting the cathode block via contact material projecting from the cathode block, the at least one horizontal barrier piece being clear of the contact material.

19. The method of claim 18, wherein the at least one horizontal barrier piece has a thickness that is less than that of the contact material.

20. A method of mitigating leakage of electrical current in an electrolytic cell for aluminum production, the electrolytic cell comprising a cathode block having an outer perimeter and a contact area raised from the cathode block at a location spaced from the outer perimeter, the cathode block defining a bottom of a pot of the electrolytic cell, the method comprising: lowering an anode of the electrolytic cell inside the pot onto the contact area; adding solid electrolyte material at the bottom of the pot alongside the anode; delivering the electrical current from the anode to the cathode block via the contact area; and hindering transfer of moisture to the solid electrolyte material inside the pot from at least one humid component of the electrolytic cell defining a portion of the pot located outside of the outer perimeter.

21. The method of claim 20, further comprising covering the at least one humid component with a barrier, the barrier hindering the transfer of moisture from the at least one humid component.

22. The method of claim 21 , wherein the barrier is constructed of cardboard.

23. The method of claim 21 , wherein the at least one humid component includes a peripheral joint surrounding the outer perimeter of the cathode block at the bottom of the pot, the barrier extending horizontally across the peripheral joint.

24. The method of claim 23, wherein the barrier extends horizontally to between the cathode block and the anode.

25. The method of claim 23, wherein the barrier extends vertically from the peripheral joint to alongside the anode.

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