JP2009233685A - Method for recycling sliding nozzle plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recycling a sliding nozzle plate, a method in which extension of a durable period can be attained by overall repairing damage of a used sliding nozzle plate and in which general applicability is afforded. <P>SOLUTION: The recycling method of a sliding nozzle plate includes an impregnation step S2 in which a refractory layer of a used sliding nozzle plate is impregnated with tar or pitch and a heating step S3 in which the used sliding nozzle plate impregnated with tar or pitch is heated to remove volatile components from the tar or the pitch. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for regenerating a sliding nozzle plate, which performs a process for extending the useful life of a sliding nozzle plate used for discharge control and flow rate adjustment of molten steel in a steelmaking process.

  The sliding nozzle device is a device used for discharge control and flow rate adjustment of molten steel when discharging molten steel from a molten steel container such as a ladle or a tundish in a steelmaking process. As shown in FIG. 3A, a general sliding nozzle device 100 includes an upper nozzle 101 fitted in the opening of the bottom 90 of the molten steel container, a fixed plate 111 fixed to the bottom of the upper nozzle 101, A sliding plate 112 that slides by reciprocating or rotating with respect to the fixed plate 111 and a lower nozzle 102 to which the sliding plate 112 is fixed are provided. The fixing plate 111 and the sliding plate 112 are provided with through holes 111h and 112h, respectively. The through hole 111h of the fixing plate 111 is the nozzle hole 101p of the upper nozzle 101 and the through hole 112h of the sliding plate 112 is. The position coincides with the nozzle hole 102p of the lower nozzle 102. With such a configuration, the sliding of the sliding plate 112 switches the nozzle hole 101p of the upper nozzle 101 and the nozzle hole 102p of the lower nozzle 102 to communication or non-communication, and discharge or stop discharging of the molten steel from the molten steel container. Is controlled, and the flow rate of the molten steel is adjusted by changing the size of the portion where the through hole 111h of the fixed plate 111 and the through hole 112h of the sliding plate 112 communicate with each other.

  3A illustrates the case where the sliding nozzle device 100 includes two sliding nozzle plates 111 and 112, but the upper fixing plate 121 fixed to the upper nozzle as illustrated in FIG. 3B. A sliding nozzle device including three sliding nozzle plates, a lower fixing plate 122 fixed to the lower nozzle, and a sliding plate 123 that slides between the upper fixing plate 121 and the lower fixing plate 122 is also used.

  The sliding nozzle plate used in this way is severely damaged by contact with hot molten steel or slag. For example, in the sliding plate 112, as shown in FIG. 4, in the peripheral portion A of the through hole 112h through which the molten steel is circulated when the molten steel is discharged, in addition to physical erosion due to the flowing molten steel, peeling or cracking due to thermal shock occurs. It is easy to occur and is extremely damaged. Moreover, in the part B which receives molten steel at the time of the discharge stop of molten steel, the structural spalling by the chemical erosion by molten steel and the penetration | invasion of the molten steel in a structure | tissue is remarkable. And the part C to which a contact part with molten steel moves with the sliding of the sliding plate 112 is damaged by molten steel similarly although the grade is lighter than parts A and B. Furthermore, the sliding surface 112s is worn and has a rough surface by being rubbed against the fixed plate while receiving a large load in the direction of gravity. For this reason, the sliding plate has a short service life and needs to be replaced with a new one as appropriate, which is costly and wastes resources.

  Therefore, a recycling method has been proposed in which a used sliding nozzle plate is subjected to a process for extending its useful life. For example, a recycling method has been proposed in which one of two sliding nozzle plates is set thick in advance, the damaged surface of the thicker plate is polished after use, and only the thinner plate is replaced with a new one. (See Patent Document 1). Alternatively, as shown in FIG. 5, the used sliding nozzle plate 201 with the peripheral edge of the through hole 205 damaged (FIG. 5 (a)) is arranged around the through hole with a dedicated bit so that the hole diameter changes step by step. Cutting (FIG. 5 (b)), fitting the concentric cylindrical cylinder 210 into the through-hole (FIG. 5 (c)), polishing the surface that was originally the non-sliding surface 201s and newly sliding A reproduction method used as a surface has also been proposed (see Patent Document 2).

Japanese Patent No. 3272345 JP 2003-181626 A

  However, the reproduction method of Patent Document 1 cannot be applied unless one of the plates is set to be thick in advance. Moreover, in the sliding nozzle plate damaged by molten steel, since the structure is brittle and rough, there is a problem in that cracks and peeling are enlarged by mechanical polishing. In particular, due to advantages such as high resistance to structural spalling, carbon-based refractory bricks that are frequently used in sliding nozzle plates in recent years lose carbon content due to use in an oxidizing atmosphere, and the structure becomes porous. The problem of cracking and peeling due to mechanical polishing was significant.

  On the other hand, since the joint portion is formed by adhering the cylindrical body to the through hole in the recycling method of Patent Document 2, there is a possibility that the molten steel leaks through the joint portion. Further, although the damaged portion around the through hole is removed, there is a problem that no other regenerating process is performed on other damaged portions such as the portion B and the portion C described with reference to FIG.

  Accordingly, in view of the above circumstances, the present invention provides a method for regenerating a sliding nozzle plate that can repair damaged sliding nozzle plates as a whole and extend their useful life, and has versatility. It is to be an issue.

  In order to solve the above-mentioned problems, the method for regenerating a sliding nozzle plate according to the present invention includes the steps of “an impregnation step of impregnating a refractory layer of a used sliding nozzle plate with tar or pitch and the use of impregnating tar or pitch” A heating step of heating the used sliding nozzle plate and removing volatile components from the tar or pitch.

  As described above, the “sliding nozzle plate” is a combination of the upper fixing plate, the sliding plate, and the lower fixing plate even if the sliding nozzle plate is a combination of the fixing plate and the sliding plate. A sliding nozzle plate may be used. Also, the sliding direction may be either reciprocating or rotating. That is, the present invention can be applied to any sliding nozzle plate having a configuration in which each through hole is connected or disconnected by relative sliding.

  The refractory layer of the used sliding nozzle plate includes high alumina, alumina-carbon, alumina-magnesia, magnesia, magnesia-carbon, alumina-magnesia-carbon, alumina-spinel-carbon, Examples include refractory bricks such as alumina-zirconia-carbon, zirconia.

  Examples of “tar or pitch” include anhydrous tar, coal-based pitch, and petroleum-based pitch. Here, the coal-based pitch is classified according to its softening point into a soft pitch (softening point of about 70 ° C. or lower), a medium pitch (softening point of 70 to 85 ° C.), or a hard pitch (softening point of about 85 ° C. or higher). Any of them can be used. The “tar or pitch impregnation” can be performed by immersing a used sliding nozzle plate in a tar or pitch impregnating liquid for a predetermined time. At this time, since the lower the viscosity of the impregnating liquid, the easier it is to impregnate the voids of the refractory layer, the tar or pitch may be heated to lower the viscosity. Alternatively, a diluent can be used to reduce the viscosity of the tar or pitch. In addition, the density of the structure | tissue after an impregnation can be made high, so that the value of the fixed carbon of tar or pitch is high, but generally a softening point becomes high, so that the value of fixed carbon is large. Therefore, when using a pitch having a large fixed carbon value, the impregnation step is performed by heating the impregnation liquid to a higher temperature.

  The “heating step” is a step of removing the volatile components contained in the tar or pitch by heating the sliding nozzle plate impregnated with the tar or pitch, but it is required to completely remove the volatile components. It is not something.

  With the above configuration, according to the present invention, tar or pitch penetrates into the refractory layer damaged by contact with high-temperature molten steel or slag and having a brittle and rough structure in the impregnation step. As a result, the damaged portion is filled with tar or pitch and repaired, the refractory layer is densified, and the progress of cracking and exfoliation are prevented by the caking action of the tar or pitch. Thereby, the useful life of the used sliding nozzle plate can be extended.

  Moreover, since the impregnation of tar or pitch can be performed by immersing the entire sliding nozzle plate in the impregnating liquid, the entire used sliding nozzle plate can be subjected to a regeneration process for repairing damage. Thereby, according to this invention, the damage to the peripheral part of the through-hole which distribute | circulates molten steel, the part which receives molten steel at the time of the discharge stop of molten steel, and the sliding surface of a sliding nozzle plate can be repaired simultaneously. Moreover, since the impregnation process and the heating process are not affected by the type and size of the sliding nozzle plate, the present invention has versatility.

  The method for regenerating a sliding nozzle plate according to the present invention may be “the refractory layer is a carbonaceous refractory brick”.

  Examples of the “carbonaceous refractory brick” include refractory bricks such as alumina-carbonaceous, magnesia-carbonaceous, alumina-magnesia-carbonaceous, alumina-spinel-carbonaceous, and alumina-zirconia-carbonaceous.

  Carbon fire refractory bricks have properties such as high thermal shock resistance, low coefficient of thermal expansion, excellent resistance to chemical erosion, low wettability to molten metal, etc., so sliding nozzles used in harsh environments Suitable as a refractory layer for the plate. However, since it is carbonaceous, it has a disadvantage of being easily oxidized in an oxidizing atmosphere. In addition, since the carbon content of the molten steel is extremely low in the steelmaking process, carbon tends to be eluted from the carbonaceous refractory brick into the molten steel by contact with the molten steel. That is, it is difficult to avoid the loss of carbon in the carbonaceous refractory brick due to the oxidation reaction or elution, and the structure becomes porous. Therefore, the present invention in which the voids in the refractory layer are filled with tar or pitch in the impregnation step is very useful as a method for regenerating a sliding nozzle plate using a carbonaceous refractory brick that is difficult to prevent the structure from becoming porous by use. Is suitable.

  In addition to the above-described structure, the sliding nozzle plate regeneration method according to the present invention includes the following: “Before the impregnation step or after the heating step, the peripheral portion of the through hole of the used sliding nozzle plate is cut to form the through hole. A hole edge cutting step to be enlarged "may be included. Here, in the present invention, the sliding nozzle plate that has been subjected to the hole edge cutting step is reused with the size of the enlarged through hole being maintained.

  Conventionally, in order to regenerate a used sliding nozzle plate, when a peripheral portion of a damaged through hole is cut, a person skilled in the art attempts to return the size of the through hole to the original size. It was an idea (see Patent Document 2). This is because, in a sliding nozzle device, the nozzle hole of the upper nozzle, the nozzle hole of the lower nozzle, and the through hole of the sliding nozzle plate are usually set to the same diameter.

  Contrary to the common knowledge of those skilled in the art, the present inventors have come to realize that the size of the through hole of the used sliding nozzle plate after regeneration does not necessarily have to be restored to the original size. That is, when the damaged peripheral edge is cut and the size of the through-hole is enlarged, in adjusting the flow rate of the molten steel, how to adjust the size of the portion where each through-hole of the superimposed sliding nozzle plate communicates is Even if it changes, adjustment of the flow rate of the molten steel itself can be performed without any trouble. In addition, one of the upper nozzle and lower nozzle may be replaced with a new one. In such a case, the used sliding nozzle plate after regeneration is combined with the new sliding nozzle plate, and the used sliding nozzle plate after regeneration is used. It is preferable to arrange it on the side of the nozzle that continues to be used. As a result, the hole diameter of the nozzle enlarged due to wear and the hole diameter of the regenerated sliding nozzle plate can be easily matched.

  Therefore, according to the present invention, unlike the prior art, it is not necessary to insert a new cylindrical body into the through hole whose peripheral edge has been cut and to return the size of the through hole to the original, so that the process is simple. The sliding nozzle plate can be regenerated without time and effort. In addition, unlike the conventional technique in which a cylindrical body is inserted into a through-hole enlarged by cutting the peripheral edge, a new joint is not formed by the regeneration process, so that molten steel may leak through the joint. It is possible to avoid the problem of the prior art that there is.

  As described above, as an effect of the present invention, there is provided a method for regenerating a sliding nozzle plate that can repair the damage of a used sliding nozzle plate as a whole and extend its useful life, and has versatility. be able to.

  Hereinafter, a method for regenerating a sliding nozzle plate, which is the best embodiment of the present invention, will be described with reference to FIGS. Here, FIG. 1 is a process diagram of the sliding nozzle plate regeneration method of this embodiment, and FIG. 2 is an explanatory diagram for explaining the use of the used sliding nozzle plate regenerated by the method of FIG.

  As shown in FIG. 1, the sliding nozzle plate regeneration method of the present embodiment (hereinafter simply referred to as “regeneration method”) includes a recovery step S1 in which a used sliding nozzle plate is removed from the sliding nozzle device and recovered. Impregnation step S2 for impregnating the refractory layer of the used sliding nozzle plate with tar or pitch, and the heating step for heating the used sliding nozzle plate impregnated with tar or pitch to remove volatile components from the tar or pitch. S3, a blasting step S4 for blasting the used sliding nozzle plate after heating, and a hole edge cutting step S5 for cutting the peripheral portion of the through hole damaged by contact with the molten steel or slag and expanding the through hole It has. In the following description, the sliding nozzle plate is referred to as an “SN plate”.

  More specifically, in the collecting step S1, the SN plate is collected before reaching the number of uses set as the service life limit. This is because if the SN plate damages too much, the effect of the regeneration method of the present embodiment cannot be fully exhibited. For example, when the used SN plate is discarded without being regenerated and the normal service life limit is set to n charge, it is preferable to collect it after using (2n / 3) charge. is there. Specifically, in the case of an SN plate that is normally removed after 7 to 8 charges and discarded, it is removed and collected at 5 to 6 charges, and the following processing is performed.

  In the impregnation step S2, a tar or pitch impregnation solution is prepared, and the used SN plate is immersed in the impregnation solution for a predetermined time. Here, in order to facilitate impregnation of tar or pitch into the refractory layer of the SN plate, this step can be performed while heating for the purpose of reducing the viscosity of the tar or pitch. Further, the refractory layer can be forcibly impregnated with tar or pitch by performing the impregnation step while pressurizing the impregnation liquid. In addition, prior to the impregnation step S2, a step of depressurizing the used SN plate and degassing the space can be added. As a result, the refractory layer is more easily impregnated with tar or pitch.

  The heating temperature conditions of heating process S3 can be 200-400 degreeC (so-called baking) and 500-700 degreeC (so-called coking). By this step, volatile components in tar or pitch are removed, and smoke generation from the SN plate is prevented during use of the sliding nozzle device.

  After heating in the heating step S3, tar or pitch wrinkles remain on the surface of the SN plate. Therefore, in the blasting step S4, soot is removed by blasting. The processing conditions such as the type of projection material, particle diameter, and projection speed in the blasting process can be appropriately set according to the type of refractory constituting the SN plate, the type of tar or pitch, and the like.

  In the hole edge cutting step S5, the peripheral portion of the through hole is cut, but since the cross-sectional shape of the through hole is generally circular, it is cut concentrically. When the molten steel is discharged through the through hole, the peripheral portion of the through hole is subjected to physical erosion by the flowing molten steel and chemical erosion by the molten steel. In addition, cracks and delamination are likely to occur due to thermal shock received at the start and stop of molten steel discharge. Furthermore, the molten steel permeates into the refractory layer from the inner wall of the through hole, and cracks and peeling due to structural spalling that the refractory layer changes in quality tend to occur. That is, in the SN plate, the peripheral portion of the through hole is a portion that is very damaged by use. Accordingly, by cutting the peripheral edge portion of the through hole in this step, a significantly damaged portion is removed. As a result, the inner wall of the through hole becomes a new surface with almost no damage, and the resistance to the molten steel is restored, but the hole diameter is slightly larger than before the start of use.

  The used SN plate regenerated through the above-described steps S1 to S5 can be used by combining the used SN plates after regeneration, or one of the used SN plates after regeneration and a new SN plate. It can also be used in combination with a single sheet.

  For example, when multiple types of sliding nozzle devices are used in the same facility and the diameters of the nozzle holes of the upper nozzle and the lower nozzle are different between these devices, the sliding nozzle device with the smaller nozzle diameter The SN plate used in the above can be regenerated and attached to the sliding nozzle device with the larger nozzle diameter for reuse. For example, if three types of sliding nozzle devices with nozzle holes of 60 mm, 65 mm, and 70 mm are used in the same facility, the SN plate for 60 mm is used for 65 mm after regeneration, and the SN for 65 mm is used. The plate can be used for 70 mm after regeneration. In such a case, the used SN plate after regeneration can be used for both the SN plate on the upper nozzle side and the SN plate on the lower nozzle side.

  Alternatively, one of the upper nozzle and the lower nozzle can be replaced with a new one, and one used SN plate 1 after regeneration and one new SN plate 20 can be used in combination. For example, as shown in FIG. 2, when the upper nozzle 11u is continuously used without being replaced and used in combination with a new lower nozzle 12n, the used SN plate 1 after regeneration is fixed to the upper nozzle 11u side. It is preferable that the new SN plate 20 is used as a fixed plate and used as a sliding plate on the lower nozzle 12n side. As a result, the hole diameter 11p of the upper nozzle 11u expanded due to wear and the hole diameter 1h of the regenerated sliding nozzle plate 1 are easily matched.

  Moreover, when using the used SN plate 1 after reproduction | regeneration in combination with the new SN plate 20, the diameter of each through-hole 1h and 20h will differ. Therefore, when adjusting the flow rate of the molten steel by relative sliding of the SN plates 1 and 20, the size of the portion where the through holes 1h and 20h communicate with each other is changed by the diameter of the through holes of the two SN plates. However, as long as the diameters of the two are not significantly different (if the cutting in the hole edge cutting step S5 is in a common sense range), the flow rate adjustment of the molten steel itself can be performed without any problem.

  As described above, according to the regeneration method of the present embodiment, the brittle and rough structure of the refractory layer of the used SN plate is filled with tar or pitch in the impregnation step S2. As a result, the refractory layer is densified again, and the caking action of the impregnated tar or pitch prevents the progress of cracks and the spread of peeling. Thereby, the useful life of a used SN plate can be extended.

  Further, in the impregnation step S2, the entire SN plate is immersed in the impregnation solution, and a regeneration process for repairing the structure of the refractory layer is performed on the entire used SN plate. Thereby, the peripheral part of the through-hole which distribute | circulates molten steel, the part which receives molten steel at the time of the discharge stop of molten steel, and the damage in the sliding surface of SN plate can be repaired simultaneously. Moreover, since each process S1-S5 of this embodiment is not influenced by the kind and size of SN plate, the reproduction | regenerating method of this embodiment has versatility.

  Moreover, unlike the prior art, the regeneration method of the present embodiment does not include a step of inserting a new cylinder into the through hole whose peripheral portion has been cut in the hole edge cutting step S5. Thereby, it is possible to regenerate the SN plate in a simple process without taking time and effort. In addition, unlike the conventional technique in which the cylindrical body is inserted into the enlarged through hole, a new joint portion is not formed by the regeneration process, and thus there is a possibility that the molten steel may leak through the joint portion. Technical problems can be avoided.

  In addition, in this embodiment, the hole edge cutting step S5 is performed after the impregnation step S2 and the heating step S3. Thus, the structure of the refractory layer, which has become brittle and rough due to damage, is repaired to a dense and strong structure by filling the pitch, and then mechanically cut to perform penetration of the SN plate in the hole edge cutting step S5. The peripheral edge of the hole can be cut easily and cleanly.

  Specific examples will be described below. In this example, the above regeneration method is applied to an SN plate made of alumina-carbon refractory brick. The SN plate (new) of this example is prepared by mixing and kneading a raw material obtained by adding a carbon component to an alumina refractory material together with a resin-based binder, followed by drying and firing in a non-oxidizing or weakly oxidizing atmosphere. It was manufactured by doing. Further, the SN plate (new article) of this example is impregnated with pitch after firing, and then subjected to heat treatment for removing volatile components of the pitch and blast treatment for removing pitch wrinkles.

  The SN plate (new article) manufactured as described above was used in a sliding nozzle device attached to the bottom of a ladle containing 200 tons of molten steel. In this ladle, under normal use conditions, the SN plate is removed and discarded after 7 charges. In this example, after 5 charges, 12 sets of 2 SN plates were removed and collected.

  As shown in Table 1, for the collected 12 used SN plates, half of the 6 sets are set as a group that performs the playback process based on the playback method of the present invention, and the remaining 6 sets are set as a group that does not receive the playback process. The number of reuses and physical properties of the groups were compared. For the 6 sets that were reprocessed, first, the molten steel and slag partially fixed around the through-holes were removed, and after cleaning to remove the deteriorated back cushion material, the pitch of fixed carbon was about 40%. Was impregnated at about 250 ° C. and about 15 atm for about 6 hours (impregnation step). Thereafter, the volatile components of the pitch were removed by baking at a temperature of 200 to 300 ° C. for about 24 hours (heating step), and further, a blasting process for removing pitch wrinkles was performed (blasting step). For the 6 sets not subjected to the regeneration treatment, only cleaning similar to the above was performed.

  One set was subjected to the following physical property test for each of the 6 sets subjected to the regeneration treatment and the 6 pairs not subjected to the regeneration treatment. For the remaining 5 sets, a new cushion material was attached to the back surface, and the lubricant was applied to the sliding surface, and then attached to the sliding nozzle device again for use. For the group subjected to the regeneration process, the average number of times it could be reused was 4.5 charges, that is, the total number of uses was 9.5 charges. Therefore, it was possible to extend the useful life by about 36% by performing the regeneration process by the regeneration method of the present invention. On the other hand, in the group that was not subjected to the regeneration process, the number of times that it could be reused was an average of 2 charges, and the total number of uses was the same as the number of times set as the service life.

<Physical property test>
For each of the used SN plate (A) subjected to the regeneration treatment and the used SN plate (B) not subjected to the regeneration treatment, the apparent porosity, the average pore diameter, and the compressive strength were measured. The apparent porosity was measured based on JIS R2205. The average pore diameter was determined as a median diameter (diameter) from the result of measuring the pore diameter distribution using a mercury intrusion method for several test pieces cut into a size of 10 mm diameter × 20 mm height. The compressive strength was measured based on JIS R2206-1. The results are summarized in Table 2.

  As apparent from Table 2, by performing the regeneration treatment, the apparent porosity was greatly reduced, the average pore diameter was also reduced by an order of magnitude, and the compressive strength was increased by about 30 MPa. This is because the pitch is impregnated into the refractory layer, which has been damaged by contact with the molten steel and slag and relative sliding between the SN plates, and becomes rough, and the structure becomes dense. At the same time, it was considered that the development of minute cracks and the expansion of peeling were prevented by the caking action of the pitch. And it was thought by such an effect that the effect of extending the service life was obtained as described above.

  In addition, since the SN plate of this example is made of alumina-carbonaceous refractory bricks, it is inevitable that the carbon content is lost and the pores are increased by use in an oxidizing atmosphere. Therefore, it was considered that the remarkable regeneration effect was obtained as described above by the present regeneration method including the impregnation step of filling the pores with a pitch having a caking action.

  In addition, in the example implemented by changing only the temperature condition of the heating step to 500 to 600 ° C. under the same conditions as those of the group subjected to the regeneration treatment in the above embodiment, the apparent porosity after the regeneration is 5 to 5. The average pore diameter was 8%, the compressive strength was 160 to 200 MPa. This result was considered to indicate that the effect of filling the pores by the impregnation of the pitch was obtained in the same manner, although the effect was somewhat inferior to the case of baking in the heating step.

  The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements can be made without departing from the scope of the present invention as described below. And design changes are possible.

  For example, when the wear of the sliding surface is severe in the used SN plate, in addition to the above steps, a step of polishing the sliding surface by a thickness of 1 to 2 mm can be added. In this case, after a cushion material is attached to the surface opposite to the sliding surface, a plate material (for example, made of tinplate, iron, etc.) for thickness adjustment and strength reinforcement is further attached. By doing so, even if the original SN plate is not thickened as in Patent Document 1, the used SN plate thinned by polishing can be attached to the riding nozzle device again and used without any trouble. .

It is process drawing of the reproduction | regenerating method of the sliding nozzle plate of one Embodiment of this invention. It is explanatory drawing explaining use of the used sliding nozzle plate reproduced | regenerated by the method of FIG. It is a block diagram explaining a general sliding nozzle apparatus. It is (a) top view and (b) longitudinal cross-sectional view explaining the part which a sliding nozzle plate is easy to receive damage. It is explanatory drawing explaining the reproduction | regenerating method of the conventional sliding nozzle plate.

Explanation of symbols

S2 impregnation step S3 heating step S5 hole edge cutting step 1 used sliding nozzle plate 1h through hole of used sliding nozzle plate

Claims (3)

Impregnation step of impregnating tar or pitch into the refractory layer of the used sliding nozzle plate;
A method for regenerating a sliding nozzle plate, comprising: heating the used sliding nozzle plate impregnated with tar or pitch to remove volatile components from the tar or pitch.   The method for regenerating a sliding nozzle plate according to claim 1, wherein the refractory layer is a carbonaceous refractory brick.   The method further comprises a hole edge cutting step of cutting a peripheral portion of a through hole of the used sliding nozzle plate before the impregnation step or after the heating step to enlarge the through hole. The method for regenerating a sliding nozzle plate according to claim 1 or 2.

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