UA118098C2 - SIDE WALL UNIT IN ELECTROLYZER FOR ALUMINUM RESTORATION - Google Patents

Abstract

The invention relates to a side-wall block for a wall in an electrolytic cell, in particular for producing aluminum, a method for producing such a side-wall block, use of such a side-wall block, and an electrolytic cell having such a side-wall block. The side-wall block (28) is a layered body, comprising a layer having a higher thermal conductivity and a layer having a lower thermal conductivity, wherein the difference in the thermal conductivity is at least 5W/(m·K).

Description

The present invention relates to a side wall block in an electrolyzer, in particular, for obtaining aluminum, a method of manufacturing such a side block and the use of such a side block, as well as an electrolyzer with such a side block.

Electrolyzers are used for the electrolytic production of aluminum, which in industry is usually carried out by the Hall-Eru method. In the Hall-Ehr method, a melt consisting of aluminum oxide and cryolite is subjected to electrolysis, namely, which preferably consists of about 15-20 95 aluminum oxide and about 85-80 95 cryolite. At the same time cryolite,

Aluminum oxide serves to lower the melting point from 2045 "C for pure aluminum oxide to about 960 "C for a mixture containing cryolite, aluminum oxide and additional substances such as aluminum fluoride and calcium fluoride, so that the electrolysis of the melt is carried out at at a reduced temperature of about 960 "C.

The electrolyzer used in this method has a bottom, which is assembled from numerous, for example, 24 adjacent to each other, forming the cathode of the cathode blocks. A seam is formed between adjacent cathode blocks in each case. The location of cathode blocks and, if necessary, filled seams is generally indicated by the cathode bottom. The cathode bottom is surrounded by a wall formed from numerous side blocks, which, together with the cathode bottom, forms an inner bath containing a layer of aluminum and a layer of melt, which is surrounded by an outer steel bath. The seams or, respectively, the spaces between adjacent cathode blocks, as well as between cathode blocks and side blocks, are usually filled with a packing mass of carbon or a carbon-containing material such as anthracite or graphite and a binding material such as coal peck. It serves to seal against the penetration of liquid melt components and to compensate for mechanical stresses, which, for example, arise as a result of the expansion of the cathode blocks during heating in the electrolyzer commissioning mode. In order to withstand the thermal and chemical conditions prevailing during the operation of the electrolyzer, the cathode blocks are usually made of a homogeneous carbon-containing material, and the side blocks are composed of a homogeneous material containing carbon or silicon carbide. On the lower sides of the cathode blocks, in each case, grooves are provided, in which at least one current-conducting bus is placed in each case, through which the electric current supplied through the anodes is diverted. Under the cathode bottom, that is, between the cathode blocks and the bottom

The steel bath, in which the cathodes are placed, is usually lined with a refractory material, which thermally isolates the bottom of the steel bath from the cathode bottom.

At a distance of approximately 3 to 5 cm above the layer of molten liquid aluminum located on the upper side of the cathode, an anode made of separate anode blocks is placed, and between the anode and the surface of aluminum there is a melt containing aluminum oxide and cryolite. During electrolysis, which is carried out at a temperature of about 960 "C, aluminum, which is formed due to its higher density compared to the melt, sinks down below the melt layer, that is, it acts as an intermediate layer between the upper side of the cathode blocks and the melt layer. During electrolysis, aluminum oxide, dissolved in molten cryolite, decomposes into aluminum and oxygen under the action of a flowing electric current. From an electrochemical point of view, in relation to a layer of molten liquid aluminum, we are talking about the actual cathode, since on its surface aluminum ions are reduced to elemental aluminum. However, hereinafter under the term "cathode" is understood not as a cathode from an electrochemical point of view, that is, a layer of molten liquid aluminum, but as a structural part that forms the cathode bottom, composed of one or many cathode blocks.

Modern electrolyzers are operated at high values of the electrolysis current, for example, up to 600 kA, in order to ensure high performance of the electrolyzer. These high current values lead to increased heat generation during the electrolysis process. As a result of intense heat generation, it is difficult to regulate the removal of heat from the electrolyzer in such a way that such thermal conditions are achieved everywhere in the electrolyzer that would be optimal with respect to the stability and efficiency of electrolysis, as well as with respect to the service life of the electrolyzer, and, for example, the efficiency of energy use for electrolysis is reduced due to excessive losses of thermal energy in areas of high heat generation in the electrolyzer. Due to this, due to unfavorable thermal conditions in the electrolyzer, the reliability and economy of the electrolysis process, as well as the durability of the electrolyzer, deteriorate.

True, it is possible to remove excess heat, i.e., that is not necessary to support the melting process, which is released in the electrolyzer, through the bottom of the steel bath with the help of a refractory lining located between the cathode bottom and the steel bath, which usually consists of refractory bricks or plates laid in a steel bath and located one on top of the other in the area of the bottom of the steel bath. At the same time, a significant role for the temperature conditions in the area of the layer of liquid aluminum and the layer of melt in which electrolysis takes place is played by the heat transfer through the relatively thin side wall of the inner bath, formed with the help of the cathode bottom and side blocks. The heat flows in this sidewall are particularly important for the thermal conditions in the electrolyzer, since the sidewall is usually in contact with various components and environments in the electrolyzer, i.e., in particular, with the layer of liquid aluminum, the layer of liquid melt located on top of the layer of liquid aluminum of the melt with a layer of solidified melt, or, accordingly, a crust, and a gaseous atmosphere formed during the operation of the electrolyzer, with various elements contained in it.

The amounts of thermal energy that have been released must be partially diverted in a certain way, but at the same time very high heat losses must also be diverted, which mean energy losses and thereby impair the economics of the electrolysis process.

In the area of relatively thin side walls in known electrolyzers, due to the vertical construction of the side walls and the structural requirements caused by this, no additional lining of refractory bricks laid one on top of the other is provided, as in the area of the bottom of a steel bath, so that regulation of heat transfer through the side walls cannot be carried out in the same way in a simple way, as in the bottom region. Uniform sidewalls, which usually consist of a material containing carbon or silicon carbide, are uniform with respect to the thermal conductivity characteristics in the direction perpendicular to the plane of the sidewall, and provide the possibility of only limited regulation of heat flows and passage of isotherms in the sidewall in continuous operation. The seams between such a side wall and the cathode block are usually filled with a packing mass of carbon and/or a carbon-containing material such as anthracite or graphite and a binding material such as coal pitch. This seam is often stuffed manually or semi-automatically, and stuffing defects can occur, which can lead to damage to the gap or, in the worst case, even premature failure of the entire electrolyzer. This destruction often occurs only during commissioning or during continuous operation of the electrolyzer. The risk of damage becomes greater, the wider or, accordingly, the thicker the corresponding seam. In addition, a wider or, accordingly, thicker seam also means increased labor costs and

There is an increased burden on the environment and the personnel servicing the electrolyzer, as there are substances harmful to health in the traditional filling mass.

It is known to replace part or all of the packing mass required between the side blocks and the cathode blocks with an obliquely laid layer of pre-fired carbon or graphite. If only a part of this filling mass is replaced, the thickness of the seam filled with the filling mass is reduced by more than 50 to 99 95, preferably more than 75 to 99 95, especially preferably more than 90 to 99 95. It is also possible , that this layer does not fill the entire volume of the primary layer of the packing mass, for example, to create space for increasing the surface of the anode. For the most part, however, a thin seam with a filling mass remains, which runs vertically, for example, 50 mm thick. With the help of such a layer, which passes obliquely, vertically placed side blocks can be connected, for example, from silicon carbide bonded with silicon nitride. Such a design, which includes a side block and a layer that passes obliquely, is hereinafter called a "composite side block". A composite side block, in which silicon carbide bound by silicon nitride is glued to a layer that passes obliquely, is already used in modern electrolyzers. Commonly used adhesive material may contain substances harmful to health, which again means a high burden on the environment and the personnel who operate the electrolyzer. In addition, the placement of the adhesive material requires an additional technological operation. If gluing defects occur as a result of defective adhesive material or its incorrect application, this can lead to failure of the adhesive joints. The side blocks of such a composite side block consist of a uniform material and thereby do not allow differences in the thermal conductivity of the side block itself. The heat flow in the electrolyzer can also be affected by the adhesive material or, accordingly, the adhesive seam. Since the adhesive seam itself is very thin, inhomogeneities in this seam may impair the corresponding local heat flow. Carbonization of the adhesive material during commissioning of the electrolyzer can lead to a decrease in the strength of its adhesion, which can lead to a weakening of the connection between the layer that passes obliquely, made of pre-burned carbon or graphite, and the vertically installed side block. If this leads to the failure of this connection, i.e., the above-mentioned layer, which passes obliquely, and the vertically installed side block are no longer connected to each other, then the heat flow deteriorates in an unspecified way 60 and the required heat transfer can no longer be adequately provided for. This can lead to overheating of the electrolyzer, and in the worst case, to its premature failure, that is, the durability and, accordingly, the service life of the electrolyzer is reduced.

The adhesive material can also be applied between the individual side blocks that make up the side wall, in the form of a thin adhesive layer.

Patent document UE 3506200 discloses side blocks for the wall of the electrolyzer, which are a layer-by-layer formed connecting element, which contains an inner layer of carbon-containing material and an outer layer of hard ceramic material, and these two layers are tightly connected to each other. This ensures an almost unobstructed heat flow from the inside to the outside. True, when using such side blocks, there is still insufficient resistance against triggering, in particular, abrasive and/or corrosive triggering.

Therefore, on known electrolyzers, in particular, when working with high values of the electrolysis current, optimal technological conditions are not achieved, as a result of which the achievable stability and economy of the electrolysis process are limited, and the service life of the electrolyzer is shortened.

Therefore, the task of the invention is to create a side block for the wall of the electrolyzer, which, when used in the electrolyzer, provides optimal technological conditions and, accordingly, high economy and stability during electrolysis, as well as a long service life of the electrolyzer. In particular, the side block must regulate heat transfer through the side wall of the electrolyzer in such a way that optimal thermal conditions prevail in the electrolyzer during electrolysis, and heat losses during operation due to unfavorable distribution of thermal energy and temperatures are prevented to the greatest extent. At the same time, the operating temperature of the electrolyzer during electrolysis is between 920 "C and 1000 "C, preferably between 950 "C and 980 "C. In addition, this side block should have increased resistance against abrasive and/or corrosion action, especially against abrasive action. In addition, it is necessary that this side block can be manufactured, for example, without the use of adhesive material(s). In addition, this side block, when it is made in the form of a composite side block, should also provide the possibility of partial or complete rejection of the packing mass between the side wall and the cathode block.

According to the invention, this problem is solved with the help of a side block for the wall in the electrolyzer, in particular, to obtain aluminum, which is a layered element and includes a layer with a lower thermal conductivity and a layer with a higher thermal conductivity, and the difference between the lower and higher thermal conductivity is at least 5 W/meK, measured at a temperature between 920 "C and 1000 "C, preferably between 950 "C and 980 "C, and at least one of the layers is doped with silicon (powder), an oxide ceramic material or a non-oxide material. This layered element can - as explained below - be made without the use of adhesive material(s). The side block design also eliminates the need for adhesive material(s) between the individual side blocks that make up the side wall. Thanks to the shape of this layered element, it is possible - as also explained below - to partially or completely abandon the filling mass for filling the seams between the side block and the cathode block.

It was found that the execution of the side block for the electrolyzer with layers with different thermal conductivity, and at least one of the layers doped with silicon (powder), an oxide ceramic material or a non-oxide material, allows for a very simple and at the same time highly efficient adjustment of the thermal conditions in the electrolyzer at its operation in such a way that the stability and productivity of electrolysis and the service life of the electrolyzer are optimized. In addition, the resistance against activation increases, in particular, against abrasive and/or corrosive activation. If an adhesive material is used between individual side blocks, then due to the design of this side block, this adhesive material can be completely dispensed with. In addition, it was found that by giving a special shape to this side block, along with this regulation of thermal conditions, it is also possible to partially or completely dispense with the filler to fill the seam between the side block and the cathode block.

When the term "side block" is subsequently mentioned, the term may also include the aforementioned composite side blocks. As described below, the composite side block has a special shape.

Under the concepts of "lower" and, accordingly, "higher" thermal conductivity, it is necessary to understand that the corresponding layer, which has this thermal conductivity, compared to the corresponding other layer, has a "lower" or, accordingly, "higher" thermal conductivity. In particular, one of the layers consists of a material with a lower thermal conductivity, and the other layer - from a material with a higher thermal conductivity, because both materials are different from each other. If the layered element includes more than two layers, then all layers may have thermal conductivity that differs from each other, or at least two layers may have the same thermal conductivity, and/or at least two groups of layers are provided, which in each case have the same thermal conductivity. With more than two layers, it is sufficient when the difference in thermal conductivity between at least two of the layers is at least 5 W/meK - as measured at a temperature between 920 70 and 1000 C, preferably between 950" and 980 C. In particular, the thermal conductivity of the layers differs at least in one direction of the side block, and we are mainly talking about the direction, which, in particular, is perpendicular to the side wall formed by the side blocks.

The difference between lower and higher thermal conductivity - as measured at a temperature between 9207 and 1000 "C, preferably between 950 "C and 980 C - can be between 5 W/meK and 80 W/meK, preferably between 5 and 70 W/meK, especially preferably between 8 W/meK and 60 W/meK, and most preferably between 10

W/meK and 50 W/meK.

Due to the different layers of the side block with different thermal conductivity, the thermal conductivity and heat transfer through the side block and the passage of isotherms in the side wall can be purposefully adjusted. Since the side block is directly in contact with the layer of liquid aluminum and the layer of melt in which electrolysis takes place in separate areas, as a result, it is possible to directly and with high efficiency influence the temperature conditions prevailing there, which are particularly important for the stability and productivity of electrolysis, in such a way that optimal work can be ensured electrolyzer thermal conditions.

For example, different thermal conductivity can be provided in the regions of the side block, which, when using the side block in the electrolyzer, are in contact with different environments of the electrolyzer.

Similarly, along the direction of the heat flow through the side block to the outside, multiple layers with different thermal conductivity can follow each other to regulate the heat flow in the indicated direction. The optimization of thermal conditions in the electrolyzer, which is achieved thereby, leads to a significant increase in the stability and productivity of the electrolysis process and the life of the electrolyzer. The stability and productivity of the electrolysis process and the service life of the electrolyzer are also increased due to the fact that at least one of the layers is doped with silicon (powder), an oxide ceramic material or a non-oxide material.

The side blocks according to the invention, which also include composite side blocks, can be preferably in a traditional way, which corresponds to the known side blocks with uniform thermal conductivity, in each case relative to a defined spatial direction, built into the electrolyzer and used there to line the side wall of the steel bath, without the need changes in the design of the electrolyzer and without the need to take into account the disadvantages associated with this, and the side wall of the electrolyzer, in particular, in the known version, can be made relatively thin. The side blocks can be produced at low cost and with excellent mechanical stability, and in particular with very good adhesion between the different layers, for which the side blocks as a single part are fired from a single continuous raw material base element containing different raw material mixtures, corresponding to the layers being produced, and the base element may correspond to a single side block, or the fired base element may be divided into multiple side blocks. In the manufacture of a composite side block, for example, such a fired blank may first be produced to the desired polygonal shape along the entire length of the blank, before the individual composite side block is then trimmed into a plate. Preferred polygonal shapes will be discussed in more detail later. During final processing, grooves, protrusions, indentations and roughness can be made in the composite side block. It should be pointed out here again that the adhesion between the different layers of the side block according to the invention is achieved without the use of adhesive material(s).

Preferred variants of the invention are presented in the dependent clauses of the claims, in the description and in the figures.

When in the following description, reference is made to one or several layers of a side block made in the form of a layered element, this means layers with different thermal conductivity, which, in particular, in each case have a thermal conductivity that differs from the thermal conductivity of at least one other layer of the side block by 5 W/meK or more - as measured at a temperature between 920 "C and 1000 "C, preferably between 950 "C and 980 76.

In particular, both layers can follow each other in a predetermined direction, which can correspond to the direction of the heat flow relevant to the thermal conditions in the electrolyzer, and, for example, can be specified using the direction of the thickness of the side block. Due to the resulting variation in thermal conductivity across the thickness of the side block, the total heat flow through the side block can be adjusted in this direction so that 60 provides the desired passage of isotherms in the side block. But the layers can also follow each other, for example, in the direction of the height of the side block, which does not include the composite side block, and, in particular, the regions of the heights of the side block covered with different layers when it is used in the electrolyzer can be in contact with different environments of the electrolyzer - for example, such as liquid aluminum, liquid or solidified melt, gas phase. Due to the resulting variation in thermal conductivity along the height of the side block, heat removal can be adjusted in accordance with the heat release occurring in the respective environment and with the desired thermal conditions there in each case, and additionally in accordance with the chemical requirements of individual environments.

Desirable according to the invention, the matching of thermal conditions in the electrolyzer during its operation can be realized already when the side block has exactly two layers with different thermal conductivity. In addition, such a layered structure has high stability and can be manufactured with little cost and high reliability and reproducibility. But in principle, the number of different layers of the side block is not limited to just two. Instead, the side block may also include a greater number of layers, for example at least three, four, five, six or more different layers. Thanks to this, an even more differentiated local matching of the thermal conductivity characteristics of the side block and thermal conditions in the electrolyzer can be achieved. The side block preferably includes from two to four layers, especially preferably from two to three layers, most preferably two layers. If, along with the desired coordination of thermal conditions in the electrolyzer during its operation, the goal of partial or complete replacement of the packing mass between the cathode block and the side block is also set, that is, a composite side block is used, then this composite side block can also include a larger number of layers, for example, at least three , four, five, six or more different layers. The composite side block preferably includes from two to four layers, especially preferably from two to three layers, most preferably two layers.

The layers may follow each other in a predetermined direction, which may correspond, in particular, to the direction of the thickness or the height of the side block, so that a variation of the thermal conductivity of the side block in the direction of the thickness or, respectively, in the direction of the height of the side block is achieved. The side block can also have successive layers in different directions one after the other so that a variation of the thermal conductivity of the side block in different directions is achieved. For example, a plurality of side block layers following each other in a first direction may form a first sequence of layers, and a plurality of other side block layers following each other in a first direction may form a second sequence of layers, with both sequences of layers preferably following one another one after the other in a second direction different from the first direction and, in particular, perpendicular to the first direction, i.e. staggered.

According to one preferred embodiment, the layered element has an alternating sequence of a layer with lower thermal conductivity and a layer with higher thermal conductivity. This alternating sequence can be performed in a predetermined direction, which in particular corresponds to the direction of thickness or height. But it can also be the case that one alternating sequence comes from a layer with a lower thermal conductivity and a layer with a higher thermal conductivity in the first direction, and one alternating sequence is made in a second direction different from the first direction, in particular, perpendicular to the first direction At the same time, a particularly favorable characteristic of thermal conductivity is achieved when the outer layer of the layered element is a layer with a lower thermal conductivity, and the other outer layer is a layer with a higher thermal conductivity. As a result, the absorption, distribution and removal of heat through the outer surfaces of the side block, which are formed by the outer layers of the side block, are effectively and directly coordinated. It is preferable that the outer layer of the laminated element, which is in contact with the liquid aluminum and/or with the liquid melt layer, is a layer with lower thermal conductivity, and that the other outer layer of the laminated element, which is in contact with the cathode bottom and/or bath, was a layer with higher thermal conductivity. The direction in which the thermal conductivity is distinguished is the direction that is oriented perpendicular to the side wall formed by the side blocks.

In principle, the layers and/or side block can have any suitable shape. At the same time, it should be understood that the shape largely depends on the desired application of the side block, i.e. the matching of thermal conditions in the electrolyzer during its operation, separately or in combination with this matching with partial or complete replacement of the packing mass between the cathode block and the side block.

One variant of execution, which is particularly preferable in terms of thermal conductivity characteristics, as well as the manufacturability of manufacturing the side block, consists in the fact that the layers of the side block have a block shape, in particular, a rectangular shape, and are connected to each other by contact surfaces, in particular, by their support surfaces or its side surfaces. Such layers can be especially simply manufactured and allow to purposefully adjust and vary the thermal conductivity along the main directions of the side blocks, which preferably have a block shape, in particular, a rectangular shape.

The side block is preferably made in a block shape, in particular, with a rectangular shape. At the same time, the direction along the thickness of one or many layers of the side block in each case may coincide with the direction along the thickness of the side block so that the orientation of the layers is consistent with the orientation of the side block and, accordingly, with the main directions of heat transfer in the side block. The layers connected to each other by their support surfaces can accordingly follow each other in the direction of the thickness of the side block, and the layers connected to each other by their side surfaces can follow each other in the direction of the height of the side block.

In the meaning of the invention, a block is an element that has six rectangular surfaces, eight right angles and twelve edges, of which in each case at least four have the same length and are parallel to each other. If the block is a rectangle, then in each case the four edges are equal and parallel to each other.

But it is also possible that eight of the twelve ribs are of the same length, and here in each case four ribs are parallel to each other, or all the ribs are of the same length, and here also in each case the four ribs are parallel to each other.

If the side block is used in the electrolyzer as a composite side block, then a preferred embodiment of the side block is that at least one layer of the side block has a block shape, in particular, a rectangular shape, and at least one layer of the side block has a polygonal shape. These layers are connected to each other by their contact surfaces, in particular, by their support surfaces; the bearing surface of the layer having a block shape, while having either partial or full contact with the bearing surface of the layer having a polygonal shape. With full contact of the support surfaces, both layers have the same height; if there is a partial contact, then the layer having a polygonal shape has a height that is from 95 to less than 100 95, preferably from 40 to 80 95, especially preferably from 50 to 75 95 of the height of the layer having a block shape. Such layers can also be produced in a very simple way and allow, on the one hand, to purposefully match and vary the thermal conductivity along

Ko) of the main directions of the side block, on the other hand, with the help of such a side block, a partial or complete replacement of the packing mass between the side block and the cathode block is possible.

At least one layer of the composite side block has a polygonal shape. In the meaning of the invention, a polygon is understood to be a polygon, which preferably can contain from three to six angles, especially preferably from three to five angles. A polygon with four corners is understood, for example, as a rectangle, square or trapezoid. These polygons can be regular or irregular. A regular polygon within the scope of the invention is a polygon in which all sides have the same length and all internal angles have the same size. With the help of different polygonal shapes, the composite side blocks can be matched to the desired design of the electrolyzer; for example, due to the appropriate design of the composite side block, that is, the execution of the layer with a polygonal shape, a larger space for the anodes can be created. The increased areas of the anodes make it possible to apply higher current values and thereby provide higher productivity. In addition, the shape of the composite side block can be coordinated with the shape of the seam that passes first, with the filling mass. In addition, these polygons can have normal and/or rounded corners. A normal angle is the point at which two sides of the corresponding polygon meet each other. A rounded corner is understood as a corner that has a round bend that passes concavely inward, without the presence of an angular or, accordingly, ribbed change of direction on this bent area. Rounded corners compared to sharp corners have the advantage that there is a more even distribution of forces on rounded corners. This more uniform distribution of forces leads to a decrease in the resulting stresses, and thereby reduced formation of cracks and/or defects in these places of the composite side block. A polygon preferably contains only normal angles, or one vertex of the polygon is rounded and the other angles are normal angles.

At the same time, the direction along the thickness of one or many layers of the composite side block in each case may coincide with the direction along the thickness of the side block so that the orientation of the layers is consistent with the orientation of the side block and, accordingly, with the most important directions of heat transfer in the side block. Layers interconnected by their support surfaces can accordingly follow each other in the direction of the thickness of the composite side block.

The side block, in particular the composite side block, can in principle have a flat structural shape with a relatively small thickness and, in particular, a clearly greater height and width, and the side block can have a height that exceeds the width. The thickness of the side block, when the layers are connected to each other by their support surfaces, can be, for example, between 50 and 700 mm, and depends on the application option. If the side block is used only to adjust the thermal conditions in the electrolyzer, the thickness is preferably between 60 and 250 mm, especially preferably between 80 and 150 mm, most preferably between 90 and 110 mm. If a composite side block is used in the electrolyzer, the thickness is preferably between 150 and 600 mm, especially preferably between 200 and 350 mm, most preferably between 225 and 300 mm. The thickness ratio, in particular, of two layers can be, for example, no more than 1:3, preferably no more than 1:22, and especially preferably 1.1.

The width of the side block, in particular the composite side block, can be coordinated in any way with the length of the side wall of the electrolyzer, that is, it can occupy either the entire length of this side wall, or it can be only part of the length of the side wall. The length of the side wall can be, for example, either from 3500 mm to 4000 mm, or from 10000 to 15000 mm.

If the length of the side wall is from 10,000 to 15,000 mm, then the width of the side block can be this length, or the side wall is covered, for example, with side blocks in the number of 2 to

With a length of 5000 mm.

When the width of the side block occupies the entire length of the side wall of the electrolyzer, then, on the one hand, due to such a side block, you can refuse the possible use of adhesive material for seams between individual side blocks, on the other hand, the simplified installation of this side block provides time savings. In the case when the width of the side block according to the invention is only part of the length of the side wall, then at least two side blocks according to the invention are used. Within the framework of the invention, it is possible to use the side blocks corresponding to the invention with different widths, that is, the width of one individual side block can be adjusted depending on the need. When the width of the side block according to the invention, in particular the composite side block, occupies only part of the length of the side wall, it can be between 300 and 600 mm, preferably between 400 and 600 mm, especially preferably between 450 and 550 mm.

Ko) The height of the side block, in particular the composite side block, can be, for example, between 500 and 900 mm, preferably between 600 and 800 mm, especially preferably between 600 and 750 mm. In this case, the length of the block-shaped layer is taken as the height for the composite side block.

According to one preferred embodiment, the side block, which does not include a composite side block, has two layers that follow each other in the direction of the thickness of the side block, in particular, partially or completely connected to each other by their support surfaces, which in each case cover 30-70 95, preferably 50 95 of the thickness of the side block and thereby cover the entire thickness of the side block. At the same time, you need to understand that the values of the individual thickness of the layers in percentages - also in the description below - always add up to 100 95. At the same time, one layer can be extended along the entire height of the side block.

Similarly, a side block that does not include a composite side block can have two layers that follow each other in the direction of the height of the side block, in particular, connected by their side surfaces, which in each case cover 30-70 95, preferably 5095 height of the side block and thereby cover the entire height of the side block. At the same time, one layer can be extended over the entire thickness of the side block.

According to one preferred embodiment, one or more, and in particular all layers of the side block, which do not constitute a composite side block, have in each case a thickness of from 25 mm to 125 mm, preferably from 30 to 100 mm, particularly preferably from 40 to 75 mm, and most preferably from 45 to 55 mm. This is particularly advantageous when the side block has two layers which are connected to each other by their support surfaces and follow each other in the thickness direction, and in particular in each case are 30-70 95, preferably 50 956 of the thickness of the side block At the same time, the layers in each case can be extended along the entire height of the side block.

According to one additional preferred embodiment, one or more, and in particular all layers of the side block, which do not include a composite side block, when these layers are interconnected by their side surfaces and follow each other in the direction of height, have a height from 150 to 450 mm, preferably from 200 to 400 mm, especially preferably from 250 to 350 mm, and most preferably from 280 to 320 mm. This, in particular, is preferred when the side block has two layers which are connected to each other by their side surfaces, and follow each other in the direction of height, and in each case extend, in particular, by 30-70,956, preferably up to 50 95 of the height of the side block. At the same time, the layers in each case can be extended over the entire thickness of the side block. The height ratio, in particular, of the two layers can be, for example, no more than 1:3, preferably no more than 1:22, and especially preferably 1:1.

According to one exemplary embodiment of the composite side block, this side block has two layers that follow each other in the direction of the thickness of the side block, in particular, are connected to each other by their support surfaces, which in each case occupy 30-70 95, preferably 50 95 of the thickness of the side block and thereby cover the entire thickness of the side block. At the same time, it should be understood that the values of the individual thickness of the layers in percentages - also in the further description - always add up to 100 95. At the same time, one layer can partially or completely extend over the entire height of the side block. It may be that the layer having a polygonal shape either completely extends over the entire height of the layer having a rectangular shape, or it occupies from 30 95 to less than 100 95, preferably from 40 95 to 80 95, especially preferably from 50 to 75 95 height of the layer having a rectangular shape.

According to one additional preferred embodiment, one or more - and especially all - layers of the composite side block in each case have a thickness of from 75 to 250 mm, preferably from 100 to 175 mm, and especially preferably from 110 to 150 mm. It is particularly preferred when the composite side block has two layers which are partially or fully connected to each other by their support surfaces and follow each other in the thickness direction, and in particular in each case are 30-70 95, preferably 5095 thick composite side block. With full contact of the support surfaces, the layers are extended along the entire height of the composite side block; if, on the contrary, partial contact of the support surfaces takes place, then the layer having a polygonal shape occupies from 30 to less than 100 95, preferably from 40 to 80 95, especially preferably from 50 to 75 95 of the height of the layer having a rectangular shape.

According to one additional embodiment, one or more rectangular layers, and in particular all rectangular layers of the composite side block have a height of from 500 to 900 mm, preferably from 650 to 850 mm, especially preferably from 700 to 800 mm, and one or several, and in particular all polygonal layers have a height of from 150 to less than 900 mm, preferably from 200 to 720 mm, most preferably from 250 to 675 mm.

The side block can be in contact with various components or

With the environments of the electrolyzer, in particular, with a layer of liquid aluminum, a layer of melt, under known circumstances with a crust of solidified melt located on top of the layer of melt, as well as with a gaseous atmosphere formed during the operation of the electrolyzer with various substances contained in it. In its lower region, the side block may be in connection with the cathode bottom and/or a packing mass, which may be provided to obtain a tight connection between the cathode bottom and the side block. The side block according to the above description can have numerous layers that follow each other in the direction of height, with different thermal conductivity, and preferably those regions of the heights of the side block, on which the side block is in contact with different environments, are formed by different layers of the side block.

Thanks to this, the absorption and removal of heat through the side block is consistent with the thermal conditions and requirements in the various environments that take place. Through this alignment, the side blocks are generally subjected to less stress, leading to higher wear resistance.

Alternatively or additionally, the side block may have multiple layers that follow each other in the direction of the thickness of the side block, with different thermal conductivities. As a result, the thermal conductivity of the side block can vary in the direction of the heat flow, which is oriented perpendicular to the side surface of the side block bordering the inner part of the bath.

One embodiment, which is preferred in relation to the thermal, mechanical and chemical stability of the side block, which is important for the use of the side block in an electrolyzer, is that at least one layer, preferably all layers, consist of a material selected from the group consisting of carbon, graphitic carbon, graphitized carbon, or silicon carbide, or any mixtures thereof, or containing such material. These materials are particularly suitable to withstand the effects of the conditions that occur when the side block is used in the electrolyzer and the contact of the side block with the layer of liquid aluminum and the resulting melt layer. In addition, the choice of materials with suitable compositions ensures the possibility of matching the thermal conductivity of the side block in the preferred range of values. The thermal conductivity of one or many, and in particular all layers of the side block - as measured at a temperature between 920 C and 1000 "C, preferably between 950 "C and 980 C - can be, for example, between 4 and 120

W/meK, in particular between 4 and 100 W/meK, preferably between 5 and 80 W/meK, especially preferably between 8 and 50 W/meK.

Especially high wear resistance of the side block and thus a particularly long service life of the electrolyzer equipped with a side block is achieved when the carbon is anthracite, preferably electrically calcined anthracite, and the silicon carbide is silicon carbide bound by silicon nitride.

Still further improvement in the thermal and mechanical characteristics of the side block can be achieved when the manufacture of the side block includes a step of pitch impregnation and subsequent carbonization. With this impregnation, the entire side block or at least one layer of the side block can be subjected, as described above.

At least one of the layers can be doped with silicon (powder), an oxide ceramic material, for example, such as aluminum oxide or titanium dioxide, or a non-oxide ceramic material, which preferably consists of at least one Group 4-6 metal, and at least one element of 13- 8th or 14th group of the Periodic System of Elements. Doping here means addition to the raw material mixture, and the specific content of one or more alloying additives in the raw material mixture is 3-15 95 by weight, preferably 5-10 95 by weight. Preference is given to powders made of particles with a diameter of less than 200 μm, especially preferably less than 63 μm. A number of these non-oxide materials include, in particular, metal carbides, metal borides, metal nitrides and metal carbonitrides, with metal from Groups 4-6, for example, such as titanium, zirconium, vanadium, niobium, tantalum, chromium or tungsten, and it is mainly used titanium. It is also possible to use any mixtures of oxide ceramic materials, any mixtures of non-oxide ceramic materials, any mixtures of oxide ceramic materials and non-oxide ceramic materials, any mixtures of oxide ceramic materials and silicon (powder), any any mixtures of non-oxide ceramic materials and silicon (powder), or any mixtures of oxide ceramic materials, non-oxide ceramic materials and (silicon powder. Titanium boride or titanium carbide may be used as the preferred non-oxide materials. If silicon (powder) is used, it during the firing process, it turns into silicon carbide. It is also possible to use a precursor (precursor) to obtain silicon carbide bound by silicon nitride, and a mixture of silicon carbide and silicon powder is used. Here, the firing process must be carried out with a controlled nitrogen content in the fuel gas at

From a temperature of up to 1400 "C to ensure the transformation of silicon into the actual bonding phase of silicon nitride. As a rule, heat treatment here is carried out by firing, as for ordinary ceramic materials, that is, at the firing temperature corresponding to the ceramic material used. Thus, it can be so that when manufacturing a layered element, different requirements for the firing process of the individual materials used must be taken into account.Regarding this layer, we are talking, in particular, about the layer that during operation comes into contact with the surrounding steel bath and thereby is exposed to an increased risk of oxidation.

The side block is preferably made monolithic, so that the layers of the side block are connected to each other in the form of a single continuous part and with a lock on the material. Such a connection differs from an adhesive or mechanical connection by increased stability.

At the same time, the side block can form a composite element from separate layers. As a result, a particularly high thermal, mechanical and chemical stability of the side block is obtained, and thus a particularly long service life of the electrolyzer equipped with a side block.

In particular, the side block can be obtained in one piece from a raw material, which can contain different layers corresponding to the finished side block from numerous different raw material mixtures that form the starting materials for the different layers of the side block. The side block can be obtained by burning the raw material, and, in particular, carbonization and/or graphitization of the raw material in the raw material can be carried out.

For example, the thermal conductivity of the side block can be measured at a temperature between 920 "C and 1000 C according to the standard SIM 51936. At the same time, for measurements that exceed temperatures of 400 "C, a pulsed laser is used. Within one layer, the side block can have at least substantially uniform thermal conductivity. Between a layer having a lower thermal conductivity and a layer having a higher thermal conductivity, a transition region may be formed in which the thermal conductivity, for example, decreases at least substantially continuously from a higher to a lower value. Such a transition region, which can be made relatively small compared to the total length of the layers, can be considered as part of both layers.

An additional subject of the invention is a method of manufacturing the corresponding invention of the side block described above, which includes the steps:

a) preparation of a mixture for a layer with a lower thermal conductivity, a mixture for a layer with a higher thermal conductivity, and if necessary one or many mixtures for at least one additional layer, p) formation of a raw material with a layered configuration from the mixtures according to stage a), and c) firing raw material according to stage B) at a temperature from 800 to 1400 "C, preferably from 1000 to 1300 "C.

The production of the side block by burning the raw material with various raw material mixtures, which create the starting materials for the layers, results in a solid side block with high stability and locking in the material and a monolithic bond between the individual layers of the side block.

The formation of the raw material according to stage B) may provide that the raw material mixtures are introduced into one form. At the same time, multiple layers of raw material mixtures can be formed in the form according to the layered structure of the finished side block. The production of a layered structure can be done in a simple way so that the layers of raw materials follow one another in the direction of the opening of the mold. In a particularly simple approach, the layers can be molded in such a way that they are oriented essentially horizontally, preferably horizontally, and follow one another preferably in a vertical direction.

In addition, the formation of the raw material according to stage B) may include vibration forming and/or pressing into a block of raw materials. This can be done with or without vacuuming. As a result, the cavities inside the material can be completely or partially eliminated, so that a uniform desired bulk density is achieved everywhere. In addition, particularly high homogeneity relative to the bulk density can be achieved when the formation of the raw material includes the application of pressure or, accordingly, the pressing of the raw material to compact the material.

All raw materials that can be fired to form the above-mentioned relatively ready-made lateral block of preferred materials are particularly suitable as materials for raw mixtures. For example, at least one feedstock mixture may contain a material that is selected from the group consisting of carbon-containing material, for example, such as

Of anthracite, graphite or graphitized material, for example, such as synthetic graphite and pitch, or any mixture of these materials. In addition, the mixture may contain, in particular, a carbon-containing binding material, for example, such as binding pitch.

Purposeful selection of the material composition of individual layers of raw material can be purposefully adjusted thermal conductivity of various layers of the obtained side block. When the raw material mixture includes carbon-containing material, carbonization of the material of the raw material mixture mainly occurs during firing of the raw material. In addition, graphitization of the material can be performed as an additional step 4). For this, the carbonized or raw molding product is heated at temperatures above 2000 °C, and preferably above 2200 °C.

In order to further improve the thermal and mechanical properties of the side block after stage c) firing and/or after stage a) graphitization provided for under the circumstances, an additional stage g) can be provided, which includes impregnation with pitch of the fired and, if necessary, graphitized raw material.

Preferably, the above-described method first produces a basic element with multiple layers, from which, in the step following the above-described method steps, e are separated, in particular, in the cutting process, numerous side blocks with the desired dimensions. This is also true for the production of a composite side block.

An additional subject of the invention is the side block obtained by the method described here. The side block when used in an electrolyzer ensures optimization of thermal conditions in the electrolyzer during electrolysis and, in addition, has high mechanical stability and very strong adhesion between the different layers of the side block. Depending on the width of the side block, you can refuse the adhesive material between the side blocks. If a composite side block is used, then, in addition, the packing mass between the side block and the cathode block can be partially or completely abandoned.

The application of the corresponding invention of the side block according to this description for the lining of the side walls in the electrolyzer is an additional independent object of this invention. Within the framework of the invention, it is also possible that for the lining of the side wall also at least one side block, which is used for matching thermal conditions, is combined with at least one composite side block. The number of side blocks used here, and thus the 60 composite side blocks, can be adjusted as needed.

An additional object of the invention is an electrolyzer, in particular, for the production of aluminum, which includes a cathode, an anode and a wall, and at least one part of the wall is formed by a side block corresponding to the invention according to this description. This side block can also be a composite side block described above. Described here with respect to the side block, its manufacture and application, and in particular its use in an electrolyzer, the advantages and preferred embodiments in the corresponding application represent the advantages and preferred embodiments of the corresponding invention of the electrolyzer. At least one side block preferably forms one side wall of the bath, which contains a layer of liquid aluminum and a layer of melt. At the same time, the side block can face the side wall of the outer steel bath, which covers the inner bath formed by the side block.

As mentioned above, on the one hand, a certain part of the amount of thermal energy allocated in the electrolyzer must be diverted, but on the other hand, excessive heat losses must be diverted to ensure the given temperature distribution in the electrolyzer. Along with the side blocks described so far according to the invention and, accordingly, the composite side blocks, and the refractory lining, which is located between the cathode and the steel bath, the cathode also affects the regulation of thermal energy in the electrolyzer. When a very large amount of heat is removed from the electrolyzer, the cryolite solidifies in the melt in an excessive amount and can reach the surface of the cathode. As a result, the passage of current through the cathode is disturbed, which leads to an uneven distribution of current along the surface of the cathode and, at the same time, to increased electrical resistance and thereby reduced efficiency of energy use in the electrolyzer. Controlling the heat transfer from the cathode to the underlying refractory lining can be done effectively, while controlling the heat transfer from the cathode to the sidewalls is much more difficult. Usually, the cathode blocks that make up the cathode are made of uniform material, that is, these homogeneous cathode blocks have the same thermal conductivity, so that these cathode blocks have little or no ability to maintain optimal control of heat transfer in the electrolyzer. In particular, this is true for setting the temperature regulation of the cathode for heat transfer to the side walls.

UMO document 02/064860 describes cathode blocks which, when viewed in the direction of the long side of the cathode, have different layers having different electrical resistances, i.e. for making cathode

From the blocks, different materials (which have different values of specific electrical resistance) are applied layer by layer in the direction of the long side of the cathode. With such cathode blocks, the flow of current through the electrolyzer should approach the ideal jet characteristics also without the expensive placement of conductive buses.

Cathode blocks, which in the direction of the long side of the cathode have different layers formed due to the use of different materials, also have different thermal conductivity inside the cathode block.

Such cathode blocks can also be preferably used in order to reduce cathode-induced heat losses, in particular, in the direction of the long side of the cathode, that is, in the direction of the side walls. As a result, even on individual cathode blocks, and thus for the entire cathode in general, the direction of the heat flow is regulated. At the same time, this cathode block in the direction of the long side of the cathode preferably includes at least three layers, preferably from three layers to seven layers, especially preferably from three layers to five layers, and most preferably three layers. At the same time, there are layers with higher thermal conductivity and layers with lower thermal conductivity, and it is necessary to understand that for adjacent layers, one layer has a higher thermal conductivity compared to another layer. The difference in thermal conductivity values between the layer with higher thermal conductivity and the layer with lower thermal conductivity is at least 10 95, relative to the material with lower thermal conductivity, in the temperature range from 920 to 1000 "C, measured in the direction of the long axis of the cathode block. The cathode block can include at least two layers, which have the same thermal conductivity, that is, which consist of the same material. In this case, we can be talking about both outer, i.e., edge layers of the cathode block. With such a cathode block, by choosing the number of layers, the sequence of layers and choosing the value of thermal conductivity for each individual of the layers, it is possible to purposefully regulate the heat flow in this cathode unit.

For a situation where reduced heat removal from the electrolyzer is preferred, a cathode block can be used, which, for example, has three layers. The two outer layers, that is, the two layers that are in direct or through the packing mass thermal contact with the side wall of the electrolyzer, are layers with lower thermal conductivity, while the third, middle, layer is present as a layer with higher thermal conductivity. If, on the contrary, more intensive heat removal from the electrolyzer is desired, then in the cathode block, which has three layers, both outer layers are present, which have a higher thermal conductivity compared to the third, middle, layer.

The length of the cathode block is usually 2500-3500 mm. The length of one of the above-mentioned 60 individual layers - when viewed in the direction of the long side of the cathode - depends on the desired heat flow in the cathode unit, and can be purposefully selected depending on this heat flow. In addition, this length of a single layer depends on the number of layers in the cathode block. If, for example, there are seven layers, then a separate layer has a length of 300-600 mm. If only three layers are used, then the outer, that is, the edge layers have a length of 400 to 600 mm, and the inner layer has a length of 1700-2300 mm. Regardless of the number of layers, the outer, respectively, edge layers of the cathode block have a length of 400 to 600 mm, preferably 500 mm.

The individual layers of the specified cathode blocks are composed on the basis of carbon, that is, from a material that contains carbon. With respect to thermal conductivity, it has been found to be advantageous for the cathode block to consist of a material that contains at least 50,956 by weight, preferably at least 8,095 by weight, most preferably at least 9,095 by weight, most preferably at least 95,95 by weight, and most preferably at least 99,95 by weight of carbon. . This carbon can be selected from the group consisting of amorphous carbon, graphitic carbon, graphitized carbon, and any mixtures of two or more of the aforementioned types of carbon.

For the manufacture of these cathode blocks, the same method as for the corresponding invention of the side block described above can be used. Therefore, for the manufacture of cathode blocks in the corresponding above-mentioned variants of execution, reference is made to the method of manufacturing the corresponding invention of the side block.

For the manufacture of cathode blocks, it is also true that by burning the raw material with various raw material mixtures, which create the starting materials for the layers, a solid cathode block with high stability and material-inseparable adhesion between the individual layers of the resulting monolithic cathode block is obtained.

As materials for raw mixtures in the manufacture of cathode blocks, all raw materials that can be fired to form the above-mentioned preferred materials relative to the finished cathode block are also suitable. For example, at least one raw material mixture may contain a material that is selected from the group consisting of a carbon-containing material, for example, such as anthracite, a graphite or graphitized material, for example, such as synthetic graphite and pitch, or any mixture of these materials. In addition, the mixture may contain, in particular, a carbon-containing binder

From the material, for example, such as binding peck. Purposeful selection of the material composition of individual layers of raw material can be purposefully adjusted thermal conductivity of different layers of the obtained side block.

The shape of the layers in the cathode block can be different. Along with layers that occupy the entire height H of the cathode block, there may also be layers that occupy only part of this height H, as for example shown in Figures 10 and 11. This formation of layers can be performed depending on the desired heat flux in the cathode block, that is, with the help of this formation, along with the choice of materials of the layers, and thereby the values of thermal conductivity, this heat flow can be purposefully regulated.

With the help of a combination of the side block according to the invention with the above-mentioned cathode blocks in the electrolyzer, that is, when both the side blocks according to the invention and the above-described cathode blocks are used in the electrolyzer, the thermal conditions in the electrolyzer can be regulated even more purposefully - than only with the side blocks according to the invention alone. Thanks to this, the technological conditions in the electrolyzer are optimized, as a result of which the achievable stability and economy of the electrolysis process are improved, and the service life of the electrolyzer is increased. At the same time, it should be understood that each of the specified variants of the side block can be combined with each of the specified variants of the cathode blocks.

Next, the present invention will be described by way of example of preferred embodiments with reference to the accompanying Figures, which show:

Fig. 1 - perspective view in section of an electrolyzer according to one embodiment of the invention;

Fig. 2 - a perspective view of the side block according to one embodiment of the invention;

Fig. 3 - a perspective view of the side block according to an additional variant of the invention;

Fig. 4 is a perspective view of the base element from which multiple side blocks can be separated according to one embodiment of the invention;

Fig. 5 is a perspective view of an additional base element from which multiple side blocks can be separated according to one embodiment of the invention.

Fig. 6 - in section, various options and implementation of the composite side block;

Fig. 7 is a perspective view of a base element from which multiple composite side blocks can be separated according to one embodiment of the invention, as well as one separated composite side block;

Fig. 8 is a perspective view of an additional base element from which multiple composite side blocks can be separated in accordance with one embodiment of the invention;

Fig. 9 - a cross-section of an additional base element from which multiple composite side blocks can be separated according to one variant of the invention;

Fig. 10 - a perspective view of the cathode block, and

Fig. 11 - a cathode block having various forms of layers.

In Fig. 1 shows a perspective view in partial section of an electrolyzer for the production of aluminum according to one embodiment of the invention. The electrolyzer includes a cathode, which is composed of numerous cathode blocks 12 forming the cathode bottom. On the upper side of the cathode there is a layer 14 of liquid aluminum and on it a layer 16 of liquid melt, and on top of the layer 16 of liquid melt a layer, or crust 18, of solidified melt.

On top of the layer 16 of the melt, an anode is placed, which consists of numerous anode blocks 20 loaded into the layer 16 of the melt. During operation of the electrolyzer, the electric current is supplied through the anode blocks 30 and passes through the layer 16 of the melt and the layer 14 of liquid aluminum to the cathode blocks 12. The current is removed through the cathode blocks 12 and through the current-conducting buses 22 inserted into the corresponding grooves on the underside of the cathode blocks 12. At the same time, electrolysis takes place in the melt layer 16, which leads to the separation of elemental aluminum from the melt, which is collected on the upper side of the cathode bottom to form a layer 16 of liquid aluminum.

The electrolyzer has a steel bath 24, which serves as an outer casing, in the bottom region of which numerous plates 26 of refractory material are placed one above the other, which thermally insulate the cathode blocks 12, which lie above them, from the bottom of the steel bath 24.

The side walls of the steel tub 24 are lined with numerous rectangular side blocks 28.

Side blocks 28 form the side wall of the inner bath, in which layer 14 of liquid aluminum, layer 16 of liquid melt and layer 18 of solidified melt are laid, and its bottom is formed by the cathode bottom formed by cathode blocks 12. Formed between the cathode block 12 and the side

With the block 18, the seams are sealed with a sealing mass 30. Such a sealing mass can also be provided for sealing the seams between the cathode blocks 12 and for sealing the seams between the side blocks 28.

As shown in fig. 1, the side blocks 28 are made essentially rectangular and are installed vertically in the steel bath 24 so that the height direction of the side blocks 28 is parallel to the vertical. At the same time, the surfaces of the side blocks 28, which limit the interior of the bath, are formed by their support surfaces 32, parallel to the height direction and the width direction of the side blocks 28, and the side blocks 28 are connected to each other by their side surfaces 34, parallel to the height direction and width direction. At the same time, the side blocks 28, as shown in Fig. 1, at different parts of their height are in contact with different components and, accordingly, the electrolyzer medium, namely, with the packing mass 30 and, under known circumstances, with a layer 14 of liquid aluminum, a layer 16 of a liquid melt and a layer 18 of a solidified melt.

During operation of the electrolyzer, significant amounts of thermal energy are released in the electrolyzer.

Usually, about a third of this thermal energy is received by the side blocks 28 and transferred to the outside. At the same time, the main direction of the heat flow corresponds to the direction along the thickness of the side blocks 28. Approximately 15 95 of the thermal energy is perceived by the cathode bottom or, accordingly, the bars.

Side blocks 28 shown in fig. 1 electrolyzer in each case has at least one layer with lower thermal conductivity and one layer with higher thermal conductivity, and the difference between the lower and higher thermal conductivity is at least 5 W/meK. Thanks to this, the absorption and removal of heat through the side wall formed by the side blocks 28 are regulated in such a way that optimal thermal conditions are established everywhere in the electrolyzer during its operation, as a result of which the stability, reliability and productivity of the electrolysis process are improved, and the service life of the electrolyzer is increased.

In Fig. 2 and C show in each case a side block 28 according to one embodiment of the invention, which, for example, can be used in the one shown in FIG. 1 electrolyser. The side blocks 28 in each case have a relatively small thickness y as well as a width B and a height y that is greater than the width b.

Shown in Fig. 2 side block 28 has two layers 36, 38 of rectangular shape, and layer 36 has a lower, and layer 38 - a higher thermal conductivity. Layers 36, 38 are connected to each other by their supporting surfaces 40, 42, which are parallel to the height direction and width direction, which in each case form contact surfaces connected to each other, following each other in the direction of the thickness of the side block 28 and in each case are extended by approximately half the thickness a of the side block 28. As a result, the heat flows in the direction of the thickness and the position of the isotherms inside the side blocks 28 can be coordinated in such a way that the thermal conditions in the electrolyzer during operation are optimized.

Shown in Fig. The side block 28 also has two layers 36, 38 of a rectangular shape, and the layer 36 has a lower, and the layer 38 has a higher thermal conductivity. The layers 36, 38 are connected to each other by their side surfaces 44, 46, which are parallel to the width direction and to the thickness direction, which in each case form contact surfaces connected to each other, following each other in the direction of the height of the side block 28 and in each case are extended by approximately half the height n of the side block 28. At the same time, relative to the location in the electrolyzer, the upper half of the height is preferably formed by a layer 36 with a lower thermal conductivity. As a result, the thermal conductivity through the side block 28 can be matched to the various components located in the appropriate region of heights in contact with the side block 28, or, accordingly, the environments of the electrolyzer and the thermal conditions there, thereby optimizing the dominant during electrolysis in the electrolyzer thermal conditions. Thus, in the case described above, the heat is dissipated due to a good thermal contact between the lower half of the height, which includes the layer 38 with higher thermal conductivity, and the cathode, which occurs through the packing mass 30.

With other thermal parameters in the electrolyzer, it may be appropriate to reverse the arrangement of the layers with respect to their thermal conductivity.

In Fig. 4 shows the basic element 48, which was manufactured as a semi-finished product according to the invention of the method for manufacturing the side block. The base element 48 is made with a rectangular shape and consists of a rectangular layer 36 with a lower thermal conductivity and a rectangular layer 38 with a higher thermal conductivity, which are connected to each other by their support surfaces. In the process of cutting, numerous plates can be separated from the base element 48, forming side blocks, which have two layers 36, 38 with different thermal conductivity. For this, the basic element 48, as defined by dotted lines in Fig. 4, is cut along several cutting planes that pass perpendicular to the boundary surface located

Co) between both layers 36, 38.

In Fig. 5 shows an additional base element 48, which essentially corresponds to that shown in FIG

Fig. 4 basic elements. True, the base element 48 includes two layers 36 with lower thermal conductivity and a layer 38 with higher thermal conductivity placed between them, which are connected between their support surfaces. As shown in Fig. 5, the base element 48 for the production of side blocks is cut not only along several planes perpendicular to the boundary surfaces between the layers 36, 38, but also additionally along the median plane of the layer 38, which runs parallel to these boundary surfaces, so that the obtained side blocks in each case has two layers 36, 38 with different thermal conductivity. This manufacturing method is more economical.

In Fig. 6 shows in section various variants of the corresponding invention of the composite side block 29, which, for example, can be used in the one shown in fig. 1 electrolyser.

All shown in Fig. b composite side blocks have a layer 36 of rectangular shape and a polygonal layer 38, and the layer 36 has a lower thermal conductivity, and the layer 38 has a higher thermal conductivity. The layers 36, 38 are connected to each other by their support surfaces 40, 42, which are parallel to the height direction and to the width direction, which in each case form contact surfaces connected to each other, following each other in the direction of the thickness of the composite side block 29, and are extended in each case by 30-70 95, preferably 50 95 of the thickness of the composite side block 29. The supporting surfaces 40, 42 can have partial or full contact with each other. With the help of such various designs of composite side blocks, on the one hand, the heat flows in the thickness direction and the position of the isotherms inside the composite side block 29 can be adjusted so that the thermal conditions in the electrolyzer during operation are optimized, on the other hand, it is also possible with such a composite side block 29 to partially or completely abandon the packing mass between this composite side block 29 and the cathode block.

In Fig. b(a) layer 38 has a trapezoidal shape, in Fig. 6(5) layer 38 has a triangular shape, and on

Fig. 6(c), the layer 38 has the shape of an irregular pentagon with a rounded corner. In these embodiments, the support surfaces 40, 42 have full contact. On the contrary, in Fig. b(a4) and b(e) support surfaces 40, 42 have only partial contact, and in Fig. b(4) layer 38 is a rectangle with one rounded corner, and in Fig. b(e) layer 38 has the shape of an irregular pentagon with one rounded corner.

With other thermal parameters in the electrolyzer, it may be appropriate to reverse the arrangement of the layers with respect to their thermal conductivity.

In Fig. 7 shows the base element 48, which was manufactured as a semi-finished product according to the invention of the method for manufacturing the composite side block 29. This base element 48 is made with a rectangular shape and consists of a layer 36 of a rectangular shape with a lower thermal conductivity and a layer 38 of a rectangular shape with a higher thermal conductivity, which with connected to each other by their supporting surfaces. These layers are horizontal layers. The layer 36 is machined so that this layer takes the desired polygonal shape along the entire length of the base element 48. Then, in the next step, plates of the desired width are cut from this base element 48. In this way, it is possible to use the grain orientation that occurs during the manufacture of the base element, and the resulting properties that differ in the horizontal and vertical directions, for example, such as thermal conductivity, and adjust in the side block, for which the support surfaces are selected accordingly during the processing of the base element.

In Fig. 8 shows the base element 48, which was manufactured as a semi-finished product according to the method for manufacturing the composite side block 29. This base element 48 is made with a rectangular shape and consists of two layers 36 of a rectangular shape with a lower thermal conductivity and one layer 38 of a rectangular shape with a higher thermal conductivity, which are connected to each other by their support surfaces. These layers are vertical layers, and layers 36 are both outer layers. Here, numerous plates can be cut from the base element 48, which have two outer layers 36 and one inner layer 38 with different thermal conductivity. At a further stage, the layer 38 is cut so that two blocks are obtained, from which, at an additional stage, the layer 38 is cut in such a way that the desired polygonal shape is obtained. In an alternative version, first the longitudinal direction is divided into two halves, a polygon is produced, and then, depending on the circumstances, the plates of the desired length are cut.

Here it is possible by orienting the layers during the manufacture of the corresponding basic element - or in

From a horizontal or vertical form - to influence various properties, for example, such as thermal conductivity. The basis of this is the different orientation of the grains during the formation process and the resulting dependence of physical properties on the direction.

In Fig. 9 also shows the base element 48, which was manufactured as a semi-finished product according to the invention of the method for manufacturing the composite side block 29. This base element 48 is rectangular, and is assembled like the base element 48 in Fig. 8, from two layers 36 of a rectangular shape with a lower thermal conductivity and one layer 38 of a rectangular shape with a higher thermal conductivity, which are connected to each other by their support surfaces. These layers are vertical layers, and layers 36 are both outer layers. Here, too, numerous plates can be cut from the base element 48, which have two outer layers 36 and one inner layer 38 with different thermal conductivity. Then, at a later stage, by appropriate cutting, two composite side blocks 29 having the same shape can be cut from such a separate cut-off fragment. The advantage of this method lies in the processing sequence, which ensures that there is almost no loss of material.

In Fig. 10 shows a cathode block 12 having three layers, and both outer layers consist of the same material A, and the middle layer consists of material B. The separate layers here run along the entire height of the cathode block.

In fig. 11 a) and 5) show different forms of layers in the cathode block 12, and in these cathode blocks in each case two materials are used, that is, material A and material B. At the same time, both layers of material A occupy in each case only part of the height H and lengths of the GI of the cathode block.

Examples of execution:

Example 1 execution:

The side block is made of mixture A containing 58 weight percent (95 by weight) of electrocalcined anthracite, 995 by weight of synthetic graphite, 17 96 by weight of binder pitch, 8 9o by weight of silicon, and 8 9o by weight of aluminum oxide , and mixture B containing 77 90 by weight of synthetic graphite and 23 956 by weight of binder pitch. For this, the vibroform for the production of the raw material is filled with both mixtures so that in the raw material two layers, which follow each other in the direction of the height of the side block being produced, from mixture A and mixture B follow each other. At the same time, the height of the layers in the vibroform is selected taking into account the target volume density, which is obtained by compacting the raw material after filling, so that after compaction, both layers in each case occupy half the height of the raw material.

After that, the raw material is fired in a ring furnace at a temperature of 1200 "C for the production of the base element.

After that, plates with a thickness of 10 cm are cut from the fired and pre-treated base element, which are further processed at a later stage and, for example, can be impregnated with pitch. An exemplary finished side block is 475 mm wide, 640 mm high and 100 mm thick, and relative to the installation situation of the side block in the electrolyzer, in which it is placed vertically along the direction of its height, the upper 320 mm of the height of the side block is formed by material A obtained from mixture A , and the lower 320 mm are made of material B obtained from mixture B.

At the same time, material A has a thermal conductivity of about 8 W/meK measured at room temperature in one direction of the side block, while material B in the same direction of the side block, in the orientation of the grains of materials A and B, has a thermal conductivity of about 45 W/meK.

Thermal conductivity at room temperature can be measured according to the ISO 12987 standard, namely in a certain direction, in the case of pressure loading of the starting material during the manufacture of the side block, for example, perpendicular or parallel to the direction of pressure loading, that is, against or according to the orientation of the grains.

The thermal conductivity measured at a temperature between 920 "C and 1000 "C is for the material

A is about 9 W/meK and for material B about 37 W/meK. Thermal conductivity can be measured here by grain orientation in accordance with the SIM 51936 standard using a pulsed laser.

Example 2 execution:

The composite side block is made from a mixture of A containing 58 95 by weight of electrocalcined anthracite, 9 by weight of synthetic graphite, 17 96 by weight of binder pitch, 8 9o by weight of silicon, and 8 95 by weight of aluminum oxide, and mixture B containing 65 95 by weight of synthetic graphite, 5 90 by weight of aluminum oxide, 10 95 by weight of silicon powder and 2095 by weight of binder pitch. For this, the vibroform for the production of the raw material is filled with both mixtures so that in the raw material there are two layers that follow each other in the direction of the height of the composite block being manufactured from the mixture

Mixtures A and B followed one after the other. At the same time, the height of the layers in the vibroform is selected taking into account the target volume density, which is obtained by compacting the raw material following filling, so that after compaction both layers in each case occupy half the height of the raw material. After that, the raw material is fired in a ring furnace at a temperature of 1300 "C for the production of the base element.

After that, the layer containing material A is processed so that it takes the desired polygonal shape along the entire length of the raw material. Then, at a further stage, plates with a thickness of 50 cm are cut from this base element. A sample finished composite side block is 500 mm wide, 700 mm high and 250 mm thick.

At the same time, material A has a thermal conductivity of about 8 W/meK measured at room temperature in one direction of the side block, while material B in the same direction of the side block, in the orientation of the grains of materials A and B, has a thermal conductivity of about 45 W/meK. Thermal conductivity at room temperature can be measured according to the IBO 12987 standard, namely - in a specified direction, in the case of pressure loading of the starting material during the manufacture of the side block, for example, perpendicular or parallel to the direction of pressure loading, that is, against or according to the orientation of the grains.

The thermal conductivity measured at a temperature between 920 "C and 1000 "C is for the material

A is about 9 W/meK and for material B about 37 W/meK.

Example From execution:

A cathode block is made, as shown in Fig. 10, for which the vibroform, the height of which is considered as the height of the finished raw molding product, is first filled with mixture A, then with mixture B and then again with mixture A.

At the same time, mixture A has the following composition: - 57 Uo by weight of anthracite - 24 9o by weight of graphite, and - 19 95 by weight of binder pitch.

In addition, mixture B has the following composition: - 80 90 by weight of graphite, and bo - 20 9Uo by weight of binder pitch.

The height of the layers in the vibroform is selected taking into account the target volume density, which is obtained by compacting the raw material following filling, so that after compaction, both layers in each case occupy half the height of the raw material. After that, the raw material is fired in a ring furnace at a temperature of 1200 "C for the production of the base element. At the same time, material A has a thermal conductivity of about 15 W/meK measured at room temperature in one direction of the cathode block, while material B in the same direction of the cathode block , in the orientation of the grains of materials A and B, has a thermal conductivity of about 40 W/meK. The thermal conductivity at room temperature can be measured according to the IBO 12987 standard, namely - in a specified direction, in the case of pressure loading of the source material during the manufacture of the cathode block, for example , perpendicular or parallel to the direction of pressure loading, i.e. against or according to grain orientation.

The cathode block produced in this way can have a width of 420 mm, a height of 400 mm and a length of 3100 mm, and can be used to make a cathode bottom having, for example, 24 cathode blocks. Such cathode blocks together with the corresponding side blocks of the invention can be used in an electrolyzer.

List of Conventional Designations 12 Cathode Block 14 Liquid Aluminum Layer 16 Liquid Melt Layer 18 Solidified Melt Layer 20 Anode Block 22 Conductive Bus 24 Steel Bath 26 Refractory Plate 28 Side Block 29 Composite Side Block

Filling mass 32 Support surface

From 34 Side surface 36 Layer with lower thermal conductivity 38 Layer with higher thermal conductivity 40, 42 Support surface 44, 46 Side surface 48 Base element

B Width n Height a Thickness

H Height of the cathode block

Y Length of the cathode block

Claims (15)

FORMULA OF THE INVENTION 1. A side block for a wall in an electrolyzer, and the side block (28) is a layered element including a layer (36) with a lower thermal conductivity and a layer (38) with a higher thermal conductivity, and the difference between the lower and higher thermal conductivity is at least 5 W/ m'K - as measured at a temperature between 920 "C and 1000 C, and at least one of the layers (36, 38) is doped with silicon, an oxide ceramic material or a non-oxide material. 2. Side unit according to claim 1, characterized in that the layered element has an alternating sequence of a layer (36) with a lower thermal conductivity and a layer (38) with a higher thermal conductivity. C. Side unit according to claim 2, characterized in that the outer layer of the layered element is a layer (36) with a lower thermal conductivity, and the other outer layer is a layer (38) with a higher thermal conductivity. 4. Side block according to one of claims 1-3, 60, which is characterized by the fact that the layers (36, 38) have a block shape, in particular a rectangular shape, and are connected to each other by contact surfaces, in particular by their support surfaces (40, 42) or their side surfaces (44, 46). 5. Side block according to one of claims 1-3, which is characterized in that one of the layers (36, 38) has a block shape, in particular a rectangular shape, and the other layer (36, 38) has a polygonal shape, and both layers with connected to each other by contact surfaces, in particular by their support surfaces (40, 42). 6. Side block according to claim 5, which is characterized by the fact that the layer (36, 38) having a polygonal shape is a polygon with the number of angles from three to six. 7. Side block according to one of claims 1-6, which is characterized in that, when the layers (36, 38) are connected to each other by their support surfaces (40, 42), the thickness of the layered element is from 50 to 700 mm. 8. Side block according to claim 4, which is characterized in that, when the layers (36, 38) are connected to each other by their side surfaces (44, 46), the height of the layers is from 150 to 450 mm. 9. Side block according to one of claims 1-8, characterized in that at least one layer (36, 38) consists of a material selected from the group consisting of carbon, graphitic carbon, graphitized carbon or silicon carbide, or any any mixtures thereof, or contains such material. 10. Side unit according to one of claims 1-9, which is characterized in that the difference between the lower and higher thermal conductivity is from 5 to 80 W/m'K, preferably from 5 to 70 W/m-K, especially preferably from 8 to 60 W/m'K, and most preferably between 10 W/m'K and 50 Zo W/m:K. 11. The method of manufacturing the side block (28) according to one of claims 1-10, which includes the following stages: a) preparation of the mixture for the layer (36) with lower thermal conductivity, the mixture for the layer (38) with higher thermal conductivity, p) forming the raw material with a layered configuration of mixtures according to stage a), c) firing of the raw material according to stage b) at a temperature from 1100 to 1400 "С. 12. The method according to claim 11, which differs in that the formation according to stage B) includes vibration formation. 13. Application of the side block (28) according to one of claims 1-10 for the lining of the side walls of the electrolyzer. 14. Electrolyzer, which includes a cathode (12) and an anode (20), as well as a side wall, and at least one part of the wall is formed by a side block (28) according to at least one of claims 1-10. 15. 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