Refractory plate, method for producing refractory plate, use of refractory plate, sliding gate valve for controlling flow of molten metal and container for containing molten metal

Abstract

The invention relates to a refractory plate for use in a sliding gate valve for controlling the flow of molten metal, to a method for producing a refractory plate, to the use of a refractory plate, to a sliding gate valve for controlling the flow of molten metal and to a container for containing molten metal.

Description

Technical Field

[0001] The present invention relates to a refractory plate for use in a slide gate valve for controlling the flow of molten metal, a method for producing the refractory plate, uses of the refractory plate, a slide gate valve for controlling the flow of molten metal and a container for containing molten metal. Background Art

[0002] The refractory plate in the sliding gate valve is used to control the flow rate of molten (i.e. liquid) metal, in particular steel, from a melting container for receiving liquid or molten metal, respectively. Such a container may in particular be a ladle or a tundish in a continuous casting plant for casting steel. In order to pour the metal melt in such a container into aggregate downstream of the container in terms of production, such a container has an opening, which is in particular arranged at the bottom of such a container.

[0003] Refractory plates in slide gate valves are used to control the flow of molten metal through such openings. Such plates have channels or passage openings through which the liquid metal can flow.

[0004] The sliding gate valve is located in the region of the opening of the melting container. Such sliding gate valves include several refractory plates to control the flow of molten steel from the opening. To this extent, such sliding gate valves generally include one or two fixed refractory plates, each of which has a channel aligned with the opening of the melting container. Another refractory plate (so-called "sliding gate") is flatly placed against the fixed plate, and is arranged to slide relative to these fixed plates. The sliding gate can slide into a first position, in which the channel of the sliding gate is aligned with the channel opening of the fixed plate, so that the molten metal can flow out of the melting container through the opening of the melting container and the aligned channel opening of the plate. In addition, the sliding gate can be moved to a second position, in which the channel opening of the fixed plate is closed by the sliding gate. In addition, the sliding gate can be used to throttle the flow of steel by moving it to a position between the first position and the second position. A hydraulic or electric drive can be provided to move the sliding gate.

[0005] The plates in the sliding gate valves are composed of refractory ceramic material.

[0006] During the passage of the liquid metal through the plates, it is exposed to extreme temperature changes, extreme temperatures and extreme mechanical or corrosive actions. Extreme temperature changes occur not only during the opening and closing of the gate valves, but also during the passage of the molten metal due to temperature gradients within the plates.

[0007] In order to withstand these extreme loads, the refractory ceramic material of the plate must have not only high fire resistance but also high thermal shock resistance and high corrosion resistance.

[0008] Although the sliding gates of the prior art show high thermal shock resistance and high corrosion resistance, the extreme temperature changes to which the sliding gates are subjected during their use lead to cracks in the plates. These cracks extend from the channels, through the entire plate to its outer edge, where the plate is usually enclosed by a metal frame. Due to the negative pressure generated by adjusting the channel openings to throttle the flow of steel by the sliding plate position during casting, air can be sucked into the channels via these cracks. This increases crack widening and crack propagation, which in turn increases air intake. This effect is also known as "ratholing", which in turn leads to a significant reduction in the performance of the sliding plate and an increase in operating risks (such as steel leakage, production losses, etc.).

[0009] There has been no lack of attempts to counteract the rathole effect, for example by selecting special refractory materials for the refractory plates in the slide gates. In this respect, for example, carbon-bonded refractory materials are known to have excellent refractory properties, including in particular good fire resistance (high temperature resistance), good thermal shock resistance and high corrosion resistance. However, carbon-bonded refractory materials are susceptible to the oxidizing atmosphere to which the plates in the slide gates are sometimes exposed during their use. Summary of the invention

[0010] An object of the present invention is to provide a fire resistant plate for a sliding gate valve, which has good fire resistant properties and at the same time provides high resistance to the rat hole effect. In particular, the plate should have good fire resistant properties, such as high fire resistance, good thermal shock resistance and high corrosion resistance.

[0011] Furthermore, it is an object of the present invention to provide a method for producing such a panel.

[0012] Furthermore, the present invention is directed to providing a vessel for holding molten metal comprising such a refractory plate.

[0013] In order to solve this problem, according to the present invention, there is provided a refractory plate for use in a sliding gate valve for controlling the flow of molten metal, which includes the following features: a channel extending through the plate through which molten metal can flow; A first part, the first part is made of a first refractory material; The passage at least partially passes through the first portion; and A second part, the second part is made of a second refractory material; The channel is spaced apart from the second portion; and wherein The first refractory material is bonded by a carbon bond or a coke binder; And among them The second refractory material is not bonded by carbon bonds or coke binders.

[0014] Surprisingly, it has been found according to the invention that a board formed as described above can solve the problem underlying the invention. In particular, such a refractory board can exhibit the aforementioned good fire resistant properties and at the same time form a high resistance to ratholes.

[0015] The present invention is based on the discovery that it is not possible to easily provide a refractory board which has both good fire resistant properties and high resistance to ratholes when it is made of only one refractory material. Instead, it is necessary to form the refractory board from different refractory materials, each having different properties and synergistically complementing each other in their effects.

[0016] The present invention is also based on the discovery that only carbon-bonded or coked binder-containing refractories have the desired high refractory properties of good fire resistance (high temperature resistance), good thermal shock resistance and high corrosion resistance.

[0017] "Coking binder" shall mean a binder that is capable of undergoing a coking reaction when exposed to high temperatures. The coking reaction results in carbon bonds. Furthermore, as is well known in the art, the high temperatures necessary for such coking reactions are generally reached under the operating conditions of such sliding shutters. The necessary temperature for such coking reactions starts at about 600° C. Examples of coking binders include coal tar pitch, phenolic resins (novolac, resol) and petroleum pitch.

[0018] The invention is also based on the discovery that a refractory plate in a sliding gate valve is exposed to an oxidizing atmosphere during its use substantially only in its outer region (ie, the region spaced from the channel), while the region immediately surrounding the channel is hardly exposed to such an oxidizing atmosphere.

[0019] Against the background of these findings, the inventive idea arose to provide a refractory board comprising two different refractory materials, namely a first refractory material which is carbon-bonded or has a charred binder and which surrounds a channel, and a second refractory material which is spaced apart from the channel and surrounds the first refractory material and is not bonded by carbon bonds and does not have a charred binder.

[0020] Surprisingly, according to the invention, it has been found that such refractory sliding plates also provide a high resistance to the rathole effect. This is because, surprisingly, it has been found that cracks formed in the first refractory material in the region of the channel or passage opening, respectively, extend substantially only through the first refractory material and terminate or disappear at the outer edge of the first refractory material or at the junction or transition region from the first refractory material to the second refractory material.

[0021] Although cracks are also formed in the second refractory material, they have no relation to the cracks in the first refractory material. Subsequently, the cracks will not propagate from the first refractory material to the second refractory material through the joint between the two materials. In this way, the rat hole effect can be largely or even completely suppressed.

[0022] In principle, the first refractory material can be made of any refractory material known in the art for refractory plates in sliding gate valves and which is bonded by carbon bonds or has a coke binder. Preferably, the first refractory material can be based on at least one of the following refractory materials: alumina (i.e., refractory material based on Al2O3), magnesia (i.e., refractory material based on MgO), spinel (i.e., refractory material based on MgAl2O4) and bauxite (i.e., refractory material based on Al2O3 and with traces of Fe2O3, SiO2 and TiO2). These materials can be supplemented, for example, by refractory materials based on zirconium oxide (i.e., refractory material based on ZrO2) or zirconium oxide mullite (i.e., refractory material based on ZrO2+3Al2O3·2SiO2), zirconium oxide corundum, zirconium oxide spinel or microsilicon. The refractory material can contain waste or secondary (i.e., used and recycled) raw materials. In addition, the material may include an antioxidant known from the prior art, particularly a metal or carbide. As known in the art, antioxidants are used to prevent decarburization and promote carbide formation, so as to increase the strength of the refractory. Preferably, the antioxidant exists as a powder. Preferably, the antioxidant is selected from the following group: aluminum (Al), silicon (Si), boron carbide (B4C), silicon carbide (SiC) and aluminum silicon (AlSi), aluminum magnesium (AlMg) and aluminum magnesium silicon (AlMgSi) alloy. The first refractory material may also include carbonaceous materials, such as graphite, carbon black and petroleum coke, in order to reduce porosity and / or make the matrix flexible. In the case of carbon bonds, the aforementioned materials are bonded to each other via carbon bonds, as known from the prior art. In the case where the first refractory material includes a coking binder, the material of the first refractory material (especially therefore such as the aforementioned material) is bonded via a coking binder. The coking binder may be one of the coking binders known from the prior art, which is coked by means of tempering and / or firing under reducing conditions, and thus forms a bonding carbon skeleton. In particular, the coking binder may be at least one of the following: coal tar pitch and resin. The resin may be at least one of the following: novolac and resol. Preferably, the coking binder may be at least one resin, particularly preferably at least one of the aforementioned resins.

[0023] According to a preferred embodiment, the first refractory material is composed of 2 to 20% by mass of carbon and 80 to 98% by mass of at least one oxide selected from the group consisting of Al2O3, SiO2, ZrO2 and MgO.

[0024] More preferably, the first refractory material is composed of 3 to 15% by mass of carbon, 85 to 97% by mass of at least one oxide selected from the group consisting of Al2O3, SiO2, ZrO2, and MgO.

[0025] Even more preferably, the first refractory material consists of 3 to 11% by mass of carbon, 89 to 97% by mass of at least one oxide selected from the group consisting of Al2O3, SiO2, ZrO2 and MgO.

[0026] Even more preferably, the first refractory material consists of 6 to 9% by mass of carbon, 91 to 94% by mass of at least one oxide selected from the group consisting of Al2O3, SiO2, ZrO2 and MgO.

[0027] The mass fractions of the components of the first refractory material described above are based on the total mass of the first refractory material.

[0028] The second refractory material is not bonded by carbon bonds or coke binders. Instead, the second refractory material preferably has a carbon content of less than 2% by mass, particularly preferably less than 1% by mass.

[0029] Typically, the second refractory material may be made of any refractory material known from the art for refractory plates in sliding gate valves and which is not bonded by carbon bonds and has no coking binder.

[0030] In principle, the second refractory material can be made of any refractory material known from the art and which is not bonded by carbon bonds and has no coking binder.

[0031] Preferably, the second refractory material may be based on at least one of the following refractory materials: alumina (i.e., refractory material based on Al2O3), magnesia (i.e., refractory material based on MgO), spinel (i.e., refractory material based on MgAl2O4), bauxite (i.e., refractory material based on Al2O3 with trace amounts of Fe2O3, SiO2 and TiO2), mullite and refractory clay. The refractory material may contain waste or secondary (i.e., used and recycled) raw materials. These materials may, for example, be supplemented by different additives, such as microsilica, andalusite, alumina cement (i.e., cement based on Al2O3 and CaO) and dispersants.

[0032] Preferably, the second refractory material is based on alumina, ie an Al2O3 based refractory material. "Based on" means that preferably Al2O3 is the main oxide, present in a higher mass fraction than any other oxide.

[0033] Preferably, the second refractory material consists of 35 to 99% by mass of Al2O3, less than 2% by mass of carbon, and 1 to 65% by mass of at least one of the following: SiO2, CaO and Fe2O3.

[0034] More preferably, the second refractory material consists of 50 to 99% by mass of Al2O3, less than 2% by mass of carbon, and 1 to 50% by mass of at least one of SiO2, CaO and Fe2O3.

[0035] Even more preferably, the second refractory material consists of 65 to 99% by mass of Al2O3, less than 2% by mass of carbon and 1 to 35% by mass of at least one of: SiO2, CaO and Fe2O3.

[0036] Even more preferably, the second refractory material consists of 75 to 99% by mass of Al2O3, less than 2% by mass of carbon and 1 to 25% by mass of at least one of: SiO2, CaO and Fe2O3.

[0037] Surprisingly, it has been found according to the invention that the occurrence of cracks in the second part can be additionally particularly effectively suppressed if the second refractory material is based on the oxide Al2O3 and, in addition, has specific proportions of further oxides, in particular specific proportions of the oxides SiO2, CaO and Fe2O3. In particular, the proportion of Fe2O3, especially also in combination with the proportion of SiO2, has proven to be particularly relevant for additionally particularly effectively suppressing the occurrence of cracks in the second part. The inventors assume that the second part, in particular insofar as it abuts the first part at the joint, forms a mineral phase in the presence of these oxides in a certain proportion, which imparts a certain ductility to the second part, thereby suppressing the occurrence of cracks in the second part.

[0038] Therefore, it can preferably be provided that the second refractory material is based on aluminum oxide and contains 0.05 to 5% by mass of Fe 2 O 3 , particularly preferably 0.05 to 2.0% by mass of Fe 2 O 3 .

[0039] Furthermore, it can preferably be provided that the second refractory material is based on aluminum oxide and contains 0.1 to 64.95% by mass, more preferably 0.1 to 49.95% by mass, more preferably 0.1 to 34.95% by mass, particularly preferably 0.1 to 24.95% by mass SiO2.

[0040] Preferably, the second refractory material consists of 35% to 99% by mass of Al2O3, less than 2% by mass of carbon and 1% to 65% by mass of at least one of the following: SiO2, CaO and Fe2O3; and wherein it consists of 0.05% to 5% by mass of Fe2O3 and 0.1% to 64.95% by mass of SiO2, more preferably 0.05% to 2.0% by mass of Fe2O3 and 0.1% to 64.95% by mass of SiO2.

[0041] More preferably, the second refractory material consists of 50 to 99% by mass of Al2O3, less than 2% by mass of carbon and 1 to 50% by mass of at least one of: SiO2, CaO and Fe2O3; and wherein it consists of 0.05 to 5% by mass of Fe2O3 and 0.1 to 49.95% by mass of SiO2, more preferably 0.05 to 2.0% by mass of Fe2O3 and 0.1 to 49.95% by mass of SiO2.

[0042] Even more preferably, the second refractory material consists of 65 to 99% by mass of Al2O3, less than 2% by mass of carbon and 1 to 35% by mass of at least one of the following: SiO2, CaO and Fe2O3; and wherein it consists of 0.05 to 5% by mass of Fe2O3 and 0.1 to 34.95% by mass of SiO2, more preferably 0.05 to 2.0% by mass of Fe2O3 and 0.1 to 34.95% by mass of SiO2.

[0043] Even more preferably, the second refractory material consists of 65 to 99% by mass of Al2O3, less than 2% by mass of carbon and 1 to 25% by mass of at least one of the following: SiO2, CaO and Fe2O3; and wherein it consists of 0.05 to 5% by mass of Fe2O3 and 0.1 to 24.95% by mass of SiO2, more preferably 0.05 to 2.0% by mass of Fe2O3 and 0.1 to 24.95% by mass of SiO2.

[0044] The ratio of carbon and oxide in the above-mentioned first refractory material and the second refractory material is determined by a combination of standards ISO 12677 and ISO 21068-2. For this purpose, the ratio of oxide is determined as 100% by mass according to ISO 12677. Secondly, the ratio of carbon is determined according to ISO 21068-2. Then, the determined 100% by mass oxide and the determined % by mass carbon are added. The resulting total mass (100% by mass oxide plus % by mass carbon) is then normalized to 100% by mass.

[0045] The first part of the refractory panel according to the present invention is made of a first refractory material.

[0046] Preferably, the first part is produced by pressing. Particularly preferably, the first part is produced by uniaxial pressing or isostatic pressing.

[0047] Preferably, the first part is in one piece.

[0048] By providing the first part as a single piece, it is particularly easy to manufacture and handle the production of the refractory panel according to the invention.

[0049] The second part of the refractory panel according to the invention is made of a second refractory material.

[0050] Preferably, the second part is unitary.

[0051] Particularly preferably, the second part is produced by casting.

[0052] Since the second part is integral or produced by casting, the second part has the particular advantage of being particularly easy to produce and having a particularly uniform structure. In particular, it also has the advantage of very uniform force absorption, whereby stresses can be distributed and crack propagation from the first part to the second part can be effectively prevented.

[0053] Preferably, the first part and the second part abut at the junction. To this extent, preferably, the first part is placed directly against the second part. This has the particular advantage that forces emanating from the first part can be absorbed by the second part and dissipated to the outside. This can further prevent the formation of cracks.

[0054] According to the invention, it was found that ratholes can be prevented particularly effectively if the second part completely surrounds or encloses the first part, respectively. Preferably, the second part completely surrounds the first part in the plane of the refractory board, i.e. in a plane perpendicular to the longitudinal axis of the channel. It was found that ratholes can be reduced particularly effectively if the second part completely surrounds the first part with a thickness of at least 5 mm. According to a preferred embodiment, it is therefore provided that the second part completely surrounds the first part with a thickness of at least 5 mm, more preferably with a thickness of at least 10 mm.

[0055] Furthermore, it has been found according to the invention that ratholes can be counteracted particularly effectively if the second part occupies a minimum volume, in particular at least 10% of the volume, relative to the total volume of the first part and the second part. According to a preferred embodiment, it is therefore provided that the second part has a volume in the range of 10% to 90% by volume and the first part has a volume in the range of 90% to 10% by volume, even more preferably the second part has a volume in the range of 30% to 70% by volume and the first part has a volume in the range of 70% to 30% by volume, each relative to the total volume of the first part and the second part.

[0056] Preferably, the first part and the second part are arranged in a frame.

[0057] Corresponding frames of refractory material for holding sliding panels are known in the art.The frame of the refractory panel according to the invention can be designed according to frames known from the prior art.Preferably, the frame is made of metal.

[0058] As known from the prior art, the frame may preferably comprise a bottom portion and a rim portion, which rim portion projects preferably vertically from the bottom portion at the edge of the bottom portion. Alternatively, the frame comprises only a rim portion without a bottom portion; in this case, the rim portion forms a shroud. To this extent, the rim portion forms a radially outer periphery or circumference of the frame, respectively.

[0059] Preferably, the first portion is arranged at a distance from the radially outer periphery of the frame. Thus, if the frame comprises an edge portion, as explained above, the first portion is arranged at a distance from the edge of the frame. Preferably, the distance is at least 5 mm, and particularly preferably at least 10 mm.

[0060] According to the invention, it has been found that oxidation of the first portion and the occurrence of rat holes can be counteracted particularly effectively if the first portion is arranged at a distance from the radially outer periphery of the frame.

[0061] According to a preferred embodiment, the second portion bridges the distance between the first portion and the radially outer periphery or rim of the frame.

[0062] According to the invention, it has been found that rat-holing can be particularly effectively counteracted when the second portion bridges the distance or gap between the first portion and the radially outer periphery of the frame.

[0063] The channel at least partially extends through the first part. According to a particularly preferred embodiment, the channel completely passes through the first part. In other words, the channel is completely enclosed by the first part so that the molten metal flowing through the channel does not contact the second part, and preferably only contacts the first part and thus the first refractory material.

[0064] Another object of the present invention is to provide a method for producing a refractory board according to the present invention, the method comprising the following steps: Provide the first part; providing a batch material from which the second part can be cast; casting the batch material to form a second part; Embed the first part within the second part.

[0065] As previously disclosed, the first part is made of a first refractory material, preferably by pressing.

[0066] Furthermore, a batch material is provided from which the second part can be made. Thus, the batch material can be made from the second refractory material described above. According to the invention, the batch material is provided as a castable material, i.e. a refractory castable compound. This has the particular advantage that the sliding gate according to the invention is particularly easy to manufacture.

[0067] In this respect, for producing a sliding shutter according to the invention, the batch material can be cast to form the second part so that after casting, the batch material forms the second part, whereby the first part can be embedded in the casting compound or the second part formed therefrom.

[0068] According to a particularly preferred embodiment, provision is made for the first part to be arranged first and for the batch material to then be cast around the first part in such a way that the batch material forms the second part after casting and the first part is arranged in the second part.

[0069] According to a further embodiment of the method, it is particularly preferred to further provide a frame formed as described above and to cast the batch material into the frame.

[0070] According to a further particularly preferred embodiment of the inventive concept, it is provided that the first part is first arranged in a frame and then the batch material is cast around the first part in the frame so that the batch material forms the second part and the first part is embedded in the second part. For casting, the first part and the frame can be fixed relative to each other by means of a casting mold.

[0071] A further object of the invention is the use of a refractory plate as disclosed herein in a sliding gate valve for controlling the flow of molten metal.

[0072] A further object of the present invention is a sliding gate valve for controlling the flow of molten metal comprising a refractory plate as disclosed herein.

[0073] A sliding gate valve for controlling the flow of molten metal may include one or several refractory plates as disclosed herein.

[0074] Another object of the present invention is to provide a container for containing molten metal, which includes the following features: an opening for discharging a stream of molten metal from the vessel; and A sliding gate valve as disclosed herein; wherein The flow of molten metal through the opening can be controlled by a sliding gate valve.

[0075] Preferably, the container is a ladle or tundish of a continuous casting machine for continuously casting molten metal, especially molten steel.Alternatively, the container is a ladle of an ingot casting arrangement for casting molten metal, especially molten steel.

[0076] Further features of the invention are apparent from the claims, the drawings and the accompanying description of the drawings.

[0077] All features of the invention can be combined with one another in any way, either individually or in combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Examples of embodiments of the present invention are explained in more detail below with reference to the accompanying drawings. Figure 1 A top view showing an embodiment of a refractory board according to the present invention; Figure 2 Shown by Figure 1 A sectional view of a longitudinal cross section of a plate; Figure 3 Show according to Figure 1 A perspective view of a longitudinal cross section of a plate; Figure 4 Show according to Figure 1 Results of simulation tests on the occurrence of stress-induced cracks in a plate; and Figure 5 Results of a simulation test on the occurrence of cracks in a sliding plate according to the prior art are shown. DETAILED DESCRIPTION

[0079] Figure 1 A top view of an embodiment of a fire-resistant board according to the present invention is shown. Figure 1 The refractory plate in is indicated by reference numeral 1. The plate 1 comprises a first part 2 made of a first refractory material and a second part 3 made of a second refractory material. A channel 4 extends through the first part 2 and is completely enclosed by the first part 2. The plate 1 also comprises a metal frame 6 in which the first part 2 and the second part 3 are completely integrated. The first part 2 and the second part 3 are in direct contact with each other and therefore abut at a joint 15.

[0080] The metal frame 6 comprises a bottom portion 7 and a radially outer rim portion 8 extending perpendicularly away from the edge 9 of the bottom portion 7. The bottom portion 7 has an opening 12. The frame 6 thus has a substantially bowl-shaped configuration with an opening 12 in its bottom 7. The first portion 2 has a central section 10 which is arranged mainly above the opening 12 of the bottom portion 7. The channel 4 extends along a longitudinal axis 11 and is completely guided through this central section 10 and into the opening 12, so that the channel 4 forms a free through-opening through the plate 1. At its section away from the bottom portion 7, the central section 10 has a circumferential collar 13 with an extension section 14 extending towards one side of the rim portion 8. The rim portion 8 of the frame 6 forms the radially outer periphery of the frame 6, from which the first portion 2 is always arranged at a distance.

[0081] The second part 3 occupies the entire space between the first part 2 and the metal frame 6 .

[0082] In a plane perpendicular to the longitudinal axis 11 , the first portion 2 is thus completely enclosed by the second portion 3 at any region having a minimum thickness of at least 10 mm.

[0083] With respect to the total volume of the first part 2 and the second part 3 , the first part 2 occupies approximately 35% by volume, and the second part 3 occupies approximately 65% ​​by volume.

[0084] The first portion 2 and the second portion 3 are in direct contact with each other and therefore abut at the junction 15 .

[0085] The first part 2 is a single piece and is provided as a carbon-bonded first refractory material.

[0086] With reference to Table 1, two exemplary batches of refractory material were manufactured to produce a first part 2 comprising the following raw materials (all proportions are in mass percentages, based on the respective total mass of the respective parts): Table 1 As shown in Table 1, a mixture of an alumina refractory and a zirconia corundum refractory was used in Example 1.

[0087] In Example 2, a mixture of alumina refractory and secondary raw material (alumina based) was used.

[0088] The carbon support mentioned in Table 1 comprises graphite. The antioxidant mentioned in Table 1 comprises Si and / or Al. Both batches according to Examples 1 and 2 were further mixed with a resin binder.

[0089] In each case, the batches were mixed and pressed. Furthermore, the batches according to Example 1 were fired under reducing conditions in order to form carbon bonds, while the batches according to Example 2 were only tempered. After firing and tempering, respectively, the parts produced from the batches according to Examples 1 and 2 had the following ratios of oxides and carbon (all ratios are mass percentages, based on the respective total mass of the respective parts), see Table 2 below: Example 1 Example 2 <![CDATA[Al2O3]]> 81.4 88.5 <![CDATA[SiO2]]> 8.7 4.0 <![CDATA[ZrO2]]> 3.5 2.0 C 6.0 5.1 the remaining 0.4 0.4 Table 2 The second part 3 is unitary and made of a second castable refractory material.

[0090] Two exemplary batches (Examples 3 and 4) of such a second refractory material were made to produce the second part 3, wherein raw materials in the form of alumina and bauxite were used (see Table 3). The batch also contained additives and / or dispersants and a binder (alumina refractory cement), as shown in Table 3 (all proportions are mass percentages, based on the respective total mass of the respective part): Example 3 Example 4 Plate-shaped aluminum oxide>0.0-3.0mm 58 Plate-shaped aluminum oxide>0.0-0.045mm 34 Bauxite <0.0-3.0mm 71 Bauxite <0.0-0.045mm 23 Additives / Dispersants 1.5 1 Binder (alumina refractory cement) 6.5 5 Table 3 Castables were produced by adding water to the batches of Examples 3 and 4.

[0091] The oxide compositions of two embodiments of castables according to Examples 3 and 4 are shown in Table 4 below (all proportions are in mass percentages, based on the respective total mass of the respective parts): Example 3 Example 4 <![CDATA[Al2O3]]> 97.8 85.0 <![CDATA[SiO2]]> 0.1 10.0 <![CDATA[TiO2]]> 2.5 <![CDATA[Fe2O3]]> 0.1 1.1 the remaining 2.0 1.4 Table 4 The ratios of carbon and oxides in the above-mentioned first refractory material and second refractory material according to Table 2 and Table 4 are determined according to the standard by a combination of the standards ISO 12677 and ISO 21068-2 as set forth above.

[0092] According to one embodiment, the panel 1 is manufactured by first providing a metal frame 6 and then fixing the metal frame 6 and the first part 2 relative to each other by means of a mould so that the first part 2 is positioned within the metal frame 6. The first part 2 is one of the two parts according to examples 1 or 2 above.

[0093] Subsequently, one of the two castables according to examples 3 or 4 above is cast into the frame 6 in the space between the first part 2 and the frame 6. To cure the casting compound, the panel 1 is dried at 250° C. Subsequently, an exemplary embodiment of a refractory panel according to the invention is obtained.

[0094] In order to be able to determine the resistance of the panels according to the invention to ratholes, simulation tests were carried out. The onset of cracks in the region of the passages and the propagation of the cracks in the panels caused by the stresses in the region of the passages were simulated.

[0095] exist Figure 4 , the results of such a simulation are shown. It can be clearly seen how cracks develop in the first part 3, extending from the area of ​​the channel 4 to the edge of the first part 2. However, at the junction 15 between the first part 2 and the second part 3, these cracks terminate so that they do not continue into the second part 3.

[0096] For comparison purposes, corresponding simulation tests were carried out on a sliding plate of the prior art. Figure 5 A prior art plate 100 is made of a single refractory material 101. It is easy to see how cracks extend from the area of ​​the channels 102 through the refractory material 101 to the outer edge of the plate 100. In a practical application of such a plate 100, these cracks would lead to increased rat holes.

Claims

1. A refractory plate (1) for use in a sliding gate valve for controlling the flow of molten metal, comprising the following features: 1.1 a channel (4), the channel (4) passing through the plate (1), through which molten metal can flow; 1.2 A first part (2), wherein the first part (2) is made of a first refractory material; in 1.3 The passage (4) at least partially passes through the first portion (2); and 1.4 A second part (3), wherein the second part (3) is made of a second refractory material; 1.5 The channel (4) is spaced apart from the second portion (3); and wherein 1.6 The first refractory material is bonded by a carbon bond or a coking binder; and wherein 1.7 The second refractory material is not bonded by carbon bonds or coking binders; and wherein 1.8 The second refractory material is composed of 35% to 99% by mass of Al2O3, less than 2% by mass of carbon, and 1% to 65% by mass of at least one of the following: SiO2, CaO and Fe2O3; and wherein 1.9 The first part (2) and the second part (3) are adjacent at a junction (15).

2. The fire-resistant board (1) according to claim 1, wherein: The passage (4) passes completely through the first portion (2).

3. Refractory board (1) according to at least one of the preceding claims, wherein The first part (2) is produced by pressing.

4. Refractory board (1) according to at least one of the preceding claims, wherein The first part (2) is in one piece.

5. Refractory board (1) according to at least one of the preceding claims, wherein The second part (3) is integral.

6. Refractory board (1) according to at least one of the preceding claims, wherein The first part (2) and the second part (3) are arranged in a frame (6).

7. The fire-resistant board (1) according to claim 6, wherein: The first portion (2) is arranged at a distance from a radially outer edge portion (8) of the frame (6).

8. The fire-resistant board (1) according to claim 7, wherein: The second portion (3) bridges the distance between the first portion (2) and the radially outer edge portion (8) of the frame (6).

9. Refractory board (1) according to at least one of the preceding claims, wherein The first refractory material is composed of 2 to 20% by mass of carbon and 80 to 98% by mass of at least one oxide selected from the group consisting of Al2O3, SiO2, ZrO2, and MgO.

10. A method for producing a refractory board (1) according to at least one of the preceding claims, comprising the following steps: A. providing the first part (2); B. providing a batch material from which the second part (3) can be cast; C. casting the batch material to form the second part (3); D. Embedding the first part (2) into the second part (3).

11. Use of a refractory plate (1) according to at least one of claims 1 to 9 in a sliding gate valve for controlling the flow of molten metal.

12. A sliding gate valve for controlling the flow of molten metal, comprising a refractory plate (1) according to at least one of claims 1 to 9.

13. A container for containing molten metal, Features include: 13.1 an opening for discharging a stream of molten metal from the vessel; and 13.2 The sliding gate valve according to claim 12; wherein 13.3 The flow of the molten metal through the opening can be controlled by the sliding gate valve.

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