JP4800826B2 - Tuna wall tuyere structure - Google Patents

Description

  The present invention relates to a tuyere structure that is provided on a furnace wall of a blast furnace or other blast furnace and blows hot air into the furnace, and a contractible mortar suitable for use in constructing the tuyere structure.

  FIG. 3 is a longitudinal sectional view around the tuyere structure provided on the blast furnace wall (see Patent Document 1). The tuyere structure is arranged in a state of surrounding the tuyere main body 1 made of copper or copper alloy that blows hot air into the blast furnace through the walls of the blast furnace, and the outer shell 3 And the like, and a tuyere receiving refractory 2 constituting a part of the furnace wall. The tuyere main body 1 includes a blower tuyere 1a whose tip faces the inside of the furnace, and a large circle 1b that holds the blower tuyere 1a and constitutes the trunk of the tuyere main body 1. In the Daimaru 1b, a blower branch pipe 1c for supplying hot air sent from a hot air furnace (not shown) to the blower tuyere 1a is inserted.

  The refractory for receiving tuyere 2 is formed with a truncated conical hole H whose inner diameter gradually decreases toward the inside of the furnace, and the furnace wall of the tuyere body 1 (Daimaru 1b) is formed in the hole H. The inner part in the thickness direction is fitted. On the other hand, the outer portion in the furnace wall thickness direction of the tuyere body 1 (Daimaru 1b) is supported by the outer shell 3.

  During operation of the blast furnace, the hearth wall refractory 4 and the bottom refractory (not shown) are thermally expanded by the heat of the hot metal and molten slag in the furnace. Due to this thermal expansion, the whole tuyere receiving refractory 2 disposed on the hearth wall refractory 4 tends to be pushed upward. On the other hand, since the outer shell 3 is cooled by the outside air and is forcibly cooled by a water cooling mechanism built in the stave 5, its thermal expansion is suppressed. For this reason, the tuyere body 1 receives a push-up force from the tuyere receiving refractory 2. This pushing force causes the tuyere body 1 to be damaged.

  In Patent Document 1, in order to prevent the tuyere body 1 from being damaged, a characteristic that contracts during pressurization between the tuyere body 1 (Daimaru 1b) and the tuyere receiving refractory 2, that is, contractibility ( It teaches that a fire-resistant mortar (hereinafter referred to as a contractible mortar) 6 having cushioning properties is interposed. When the tuyere receiving refractory 2 is pushed up, the contractible mortar 6 contracts and absorbs the upward displacement of the tuyere receiving refractory 2 so that excessive stress is applied to the tuyere body 1. It can be prevented from joining.

For the contractible mortar 6, a kneaded product of ceramic fiber and corundum mortar is used. In general, as the contractible mortar, for example, as disclosed in Patent Document 2, a composition comprising a fireproof aggregate mainly composed of sintered alumina, fibers made of alumina, and an organic binder such as a phenol resin. Is kneaded with water or alcohol. Patent Document 2 teaches that silicon carbide may be used for the refractory aggregate and that the amount of fiber added should be 3 to 10% by mass with respect to 100% by mass of the refractory aggregate.
JP 2002-220609 A Japanese Patent Publication No. 5-80433

  The contractible mortar 6 may come into contact with the molten slag in the blast furnace. Conventional shrinkable mortars are excellent in shrinkability but have a problem inferior in slag resistance. In particular, in the tuyere structure, the gap between the tuyere body 1 and the tuyere receiving refractory 2 is used as a normal furnace joint for the purpose of sufficiently securing the shrinkage allowance of the contractible mortar 6. Since it is thicker than that, the contact area between the contractible mortar 6 and the slag is wide, and the contractible mortar 6 is susceptible to infiltration of the slag. When slag permeates into the contractible mortar 6, the contractibility of the slag decreases, and the pushing force applied to the tuyere body 1 cannot be sufficiently relaxed, resulting in damage to the tuyere body 1.

  An object of the present invention is to provide a long-life tuyere structure that can prevent the tuyere body from being damaged over a long period of time. Another object of the present invention is to provide a contractible mortar that is excellent in slag resistance and can maintain good contractibility over a long period of time.

  The inventors first considered whether the lifetime of the tuyere structure could be extended from a structural point of view. FIG. 3 shows an example in which only the lower gap between the tuyere body 1 and the tuyere receiving refractory 2 is filled with the contractible mortar 6, but the same mortar is also put in the remaining upper gap. If it fills, the pushing-up force from a furnace bottom can be uniformly disperse | distributed upwards through the mortar. However, in this case, if the contractibility of the lower mortar deteriorates faster than the contractibility of the upper mortar due to slag infiltration, etc., the push-up force from the lower part of the furnace takes precedence over the upper mortar. The tuyere body 1 can be inclined upward. For this reason, the tuyere body 1 may be damaged. Therefore, the inventors have completed the first invention described below as a result of intensive studies in order to prevent the tuyere structure from being damaged due to the tuyere body tilting upward.

1st invention comprised the metal tuyere main body (1) hold | maintained at the furnace wall in the state which penetrated the furnace wall of the blast furnace, and comprised a part of furnace wall surrounding this tuyere main body (1) The tuyere receiving refractory (2) is formed between the tuyere main body (1) and the tuyere receiving refractory (2) in a cross-sectional view perpendicular to the thickness direction of the furnace wall. An annular joint (M) that circulates along the outer peripheral surface of the mouth body (1) is secured, and the lower arc joint (M ₁ ) below the annular joint (M) in the height direction of the blast furnace. ) Is filled with a first refractory mortar (10) having a contractibility, and the remaining upper arc joint (M ₂ ) has a higher hot contractibility than the first refractory mortar (10). It is a tuyere structure of a blast furnace wall filled with a small second refractory mortar (11).

  The inventors also thought that improvement of the contractible mortar itself could extend its life. For example, in the contractible mortar disclosed in Patent Document 2, it is considered that the slag resistance of the contractible mortar can be improved by increasing the ratio of silicon carbide powder that hardly wets the slag to the contractible mortar. However, it has been found that by simply increasing the proportion of silicon carbide powder, the slag penetration resistance is improved, but it is difficult to obtain a good contractibility. The reason for this is not necessarily clear, but it is considered that silicon carbide powder undergoes volume expansion and densifies the mortar structure in a reducing atmosphere inside the blast furnace or the like. Therefore, the inventors have completed the following second and third inventions as a result of intensive studies to realize a contractible mortar that can exhibit good contractibility when used in combination with silicon carbide powder. Is.

The second invention is a compressible mortar is used as a joint member at a position capable contact with the molten slag of blast furnace s walls, Al ₂ O ₃ accounts for 40 to 60 mass%, the balance being mainly of SiO ₂ To a refractory material containing 30 to 80% by mass of ceramic fiber and 10 to 60% by mass of silicon carbide powder having an average particle diameter of 100 μm or less, at least 70 to 160% by mass of polyhydric alcohol is added and kneaded, After the construction, the dried molded body is a contractible mortar exhibiting a contraction rate of 30% or more when a compressive stress of 1 MPa is applied at a temperature of 1200 ° C.

The third invention is a compressible mortar is used as a joint member at a position capable contact with the molten slag of blast furnace s wall, after construction, the measurement of the dried molded body is Al ₂ O ₃ 40 to 60 A temperature of 1200 ° C. is composed of 23 to 65% by mass of ceramic fibers mainly composed of SiO _{2, 8} to 40% by mass of silicon carbide powder having an average particle diameter of 100 μm or less, and 15 to 65% by mass of residual carbon. This is a contractible mortar that exhibits a contraction rate of 30% or more when a compressive stress of 1 MPa is applied below.

Here, the “molded product dried after construction” specifically means a contractible mortar heated and dried at 500 ° C. for 2 hours or more in a reducing atmosphere. “Remaining charcoal” means residual organic components such as free carbon (excluding C in SiC). In this specification, the symbol “to” is used to include both end points. In the present specification, those represented by chemical formulas such as Al ₂ O ₃ , SiO ₂ , C, etc. mean chemical components, and are represented as alumina-siliceous raw materials, carbon powder, silicon carbide powder, alumina powder, and the like. The thing shall mean the actual refractory raw material which may contain inevitable impurities.

  According to the first invention, the contractibility of the second refractory mortar is made smaller than the contractibility of the first refractory mortar in advance. Even if the shrinkability is somewhat deteriorated, the shrinkable rate of the second refractory mortar can be kept smaller than the shrinkable rate after the deterioration. That is, it is possible to maintain a state in which the pushing force from below the furnace is preferentially absorbed in the lower arc joint as compared to the upper arc joint. For this reason, it can prevent for a long time that a tuyere main body inclines upwards, and can extend the lifetime of a tuyere main body. In addition, if the contractible mortar according to the second and third inventions is used as the first refractory mortar, the life of the tuyere structure can be further extended.

  According to the second and third inventions, the silicon carbide powder improves the slag penetration resistance of the refractory mortar. Silicon carbide powder causes volume expansion and densifies the structure in a reducing atmosphere such as the inside of a blast furnace, so that the penetration of slag into the mortar can be prevented, but the shrinkage rate of the mortar may be reduced. As a result, by selecting the chemical component of the ceramic fiber and selecting the blending ratio of the ceramic fiber and the silicon carbide powder, a balance between improved shrinkability and improved slag resistance is achieved. A contractible mortar that has excellent slag resistance and can maintain good contractibility over a long period of time can be realized.

FIG. 1 shows a tuyere structure according to an embodiment of the present invention. 1 corresponds to a cross-sectional view taken along the line AA in FIG. The tuyere receiving refractory 2 is divided into two parts in the height direction of the blast furnace (vertical direction in FIG. 1) and the circumferential direction of the blast furnace wall (left and right direction in FIG. 1), for a total of four divided pieces 2a. By constructing a combination of ˜2d, a shape surrounding the tuyere body (Daimaru 1b) is obtained. In a cross-sectional view perpendicular to the thickness direction of the furnace wall, an annular joint M is provided between the tuyere body (Daimaru 1b) and the tuyere receiving refractory 2 along the outer circumferential surface of the Daimaru 1b. Has been. The annular joint M is divided into a lower arc joint M ₁ and a remaining upper arc joint M _{2 in} the height direction of the blast furnace (vertical direction in FIG. 1).

The lower arc joint M ₁ is filled with a contractible mortar 10, and the upper arc joint M ₂ is filled with a low contractibility mortar 11 having a smaller hot contractibility than the contractible mortar 10. Has been. FIG. 1 shows only one cross-sectional view. Of the inner surface of the truncated conical hole H (see FIG. 3) formed in the tuyere receiving refractory 2, the lower side in the height direction of the blast furnace is shown. The contractible mortar 10 is applied to the downward convex curved surface, and the low contractible mortar 11 is applied to the convex curved surface region above the remainder.

The height of the boundary between the lower arc joint M ₁ and the upper arc joint M ₂ is not particularly limited. For example, within an arbitrary cross section perpendicular to the thickness direction of the furnace wall, 40-60 of the total height (diameter) L of the truncated conical hole H from the lower end of the inner surface of the truncated conical hole H (see FIG. 3). % Is preferably the lower arc joint M ₁ and the upper part is the upper arc joint M ₂ .

According to the tuyere structure described above, the contraction rate of the upper arc-shaped joint portion M ₂ is made smaller than the contraction rate of the lower arc-shaped joint portion M _1. It is preferentially absorbed by parts M _1. Even if the contractibility of the contractible mortar 10 is somewhat deteriorated due to slag infiltration or the like, the contractibility of the low contractible mortar 11 can be kept smaller than the contractibility after the deterioration. Therefore, keep the state where the upward force from the furnace below is preferentially absorbed by the lower arcuate joint portion M ₁ for a long time. That is, it is possible to prevent the tuyere body (the air tuyere 1a and the Daimaru 1b) from tilting upward for a long period of time, thereby extending the life of the tuyere body.

In order to ensure the effect of preferentially absorbing the pushing-up force from the lower part of the furnace at the lower arc-shaped joint M ₁ , the hot contraction between the contractible mortar 10 and the low contractible mortar 11 is possible. The difference in shrinkage is important. Specifically, when a compressive stress of 1 MPa is applied at a temperature of 1200 ° C., the difference between the contractibility of the contractible mortar 10 and the contractibility of the low contractible mortar 11 is 5% or more, When the content is preferably 7% or more, the above effect is further improved.

  The contractibility of the contractible mortar 10 is designed according to the thickness of the joint M. For example, when the thickness of the joint M is 50 mm to 200 mm, more specifically, 60 mm to 80 mm, the contractible mortar 10 has a thickness of 30 when a compressive stress of 1 MPa is applied at a temperature of 1200 ° C. % Or more, preferably 35% or more.

[Composition of the contractible mortar 10]
Hereinafter, the composition of the contractible mortar 10 will be described. The contractible mortar 10 is prepared by adding a kneading liquid containing a polyhydric alcohol to a refractory material containing silicon carbide powder and ceramic fibers.

  Silicon carbide powder causes volume expansion in a reducing atmosphere, that is, in a CO gas atmosphere in the furnace, densifies the mortar structure, and forms a glassy layer on the surface of the mortar surface layer exposed in the furnace. Improves slag penetration of shrinkable mortar. When silicon carbide powder having an average particle diameter of 100 μm or less is used, the effect of improving slag resistance is further enhanced. From the viewpoint of further improving the slag resistance, the average particle diameter of the silicon carbide powder is preferably 10 μm to 50 μm. Here, the average particle diameter is measured by, for example, a laser diffraction method.

  The blending ratio of silicon carbide powder in the refractory material is preferably 10 to 60% by mass. When the blending ratio of the silicon carbide powder is less than 10% by mass, the effect of improving the slag resistance is insufficient. When the mixing ratio of the silicon carbide powder exceeds 60% by mass, the contractibility is insufficient as a result of decreasing the mixing ratio of the ceramic fiber.

The ceramic fiber is composed of an alumina-silica material in which Al ₂ O ₃ occupies 40 to 60% by mass with the chemical component value, and the balance is made of SiO ₂ . When the Al ₂ O ₃ content exceeds 60% by mass, the ceramic fiber becomes hard and easily broken, and it becomes difficult to maintain the contractibility over a long period of time. On the other hand, if the Al ₂ O ₃ content is less than 40% by mass, the heat resistance of the ceramic fiber becomes insufficient. By defining the Al ₂ O ₃ content as 40 to 60% by mass, in the combined use with the silicon carbide powder that causes volume expansion, it is suitable for the contractible mortar, specifically 1200 ° C. It was found that when a compressive stress of 1 MPa was applied at a temperature, a contraction rate of 30% or more could be imparted over a long period of time.

  The blending ratio of the ceramic fiber in the refractory material is preferably 30 to 80% by mass. When the blending ratio of the ceramic fiber is less than 30% by mass, it is difficult to obtain sufficient contractibility. On the other hand, when the mixing ratio of the ceramic fiber exceeds 80% by mass, it is difficult to improve the slag penetration resistance. From the standpoint of obtaining sufficient shrinkability and improving slag penetration resistance, the blending ratio of the ceramic fiber in the refractory material is more preferably 30 to 65% by mass.

  Examples of the shape of the ceramic fiber include a bulk shape, a chop shape, and a curl shape. Among these, a bulk shape that can be easily crushed and dispersed is preferable. The diameter of the ceramic fiber is preferably 10 μm or less, and the length is preferably 10 mm to 100 mm. Further, long and short fibers may be mixed within this length range.

  The refractory material may contain one or more other refractory powders selected from, for example, alumina powder, alumina-silica powder, zirconia powder, magnesia powder, carbon powder, and the like, together with the ceramic fiber and silicon carbide powder. Alumina powder is preferable from the viewpoint of improving heat resistance, and carbon powder is preferable from the viewpoint of improving slag penetration resistance. Examples of the carbon powder include graphite, coke, and carbon black. When other refractory powders such as carbon powder are included, the blending ratio in the refractory material is preferably 10% by mass or less, and more preferably 5% by mass or less.

  The polyhydric alcohol functions as a medium for dispersing and muddying the refractory material including the silicon carbide powder and the ceramic fiber. By including polyhydric alcohol in the kneading liquid, many organic components remain in the mortar even after the evaporation of the kneading liquid, and the organic component, that is, residual carbon, forms a protective film on the ceramic fiber, and the ceramic fiber is elastically deformed. Can be maintained over a long period of time. According to the inventor's research, it has been found that such an effect cannot be obtained with a monohydric alcohol.

  In addition, by using a polyhydric alcohol, an appropriate amount of residual carbon and carbon bonds can be formed without using other organic substances such as an organic binder such as resin and pitch. Although a polyhydric alcohol that functions as a solvent together with the organic binder may be used, in this embodiment, a contractible mortar can be realized by using a polyhydric alcohol without necessarily using an organic binder.

  Specific examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol such as monoethylene glycol, diethylene glycol, polyethylene glycol, and tetraethylene glycol, and trihydric alcohols such as glycerin and polyglycerin. Of these, inexpensive monoethylene glycol and diethylene glycol are preferable. It is preferable to use a polyhydric alcohol having a concentration of 98% or more. The blending amount is preferably 10% by mass or more, and more preferably 50 to 100% by mass in the proportion of the kneading liquid.

  The kneading liquid may also contain a solution such as a dispersant, a thickener, and an antifoaming agent together with the polyhydric alcohol. However, when water is included in the kneading liquid, if the blending amount is too large, the shrinkability of the mortar is adversely affected. Therefore, the blending amount of water is preferably 10% by mass or less as a proportion of the kneading liquid.

  The addition amount of polyhydric alcohol is prescribed | regulated so that 15-65 mass% of dry contractible mortar after construction may satisfy | fill the conditions comprised with a residual charcoal. Specifically, the addition amount of the polyhydric alcohol is 70 to 160% by mass as an outer shell with respect to 100% by mass of the refractory material. If it is less than this, workability at the time of construction is inferior, and if it is more, shape retention after construction is lowered. From the balance between workability and shape retention, the addition amount of the polyhydric alcohol is more preferably 100 to 150% by mass as an outer shell.

  The contractible mortar described above is 23 to 65% by mass of the ceramic fiber, 8 to 40% by mass of the silicon carbide powder, and residual carbon when heated and dried at 500 ° C. for 2 hours or more in a reducing atmosphere. It consists of 15-65 mass%. Here, the ratio of the ceramic fiber is preferably 25 to 45% by mass, and more preferably 25 to 35% by mass. Moreover, it is preferable that it is 10-35 mass%, and, as for the ratio of silicon carbide powder, it is more preferable that it is 10-20 mass%. Moreover, it is preferable that residual charcoal is 25-60 mass%, and it is more preferable that it is 40-60 mass%.

[Composition of low contractibility mortar 11]
Next, the composition of the low contractibility mortar 11 will be described in detail. The low contractibility mortar 11 is hardly required to be contractible. The linear compressibility when the compressive stress of 1 MPa is applied at a temperature of 1200 ° C. of the low contractible mortar 11 is, for example, less than 25%. For this reason, as the low contractibility mortar 11, it is also possible to use a normal refractory mortar, for example, a mortar crushed with water by adding clay to a refractory material. In this sense, there is also an advantage that the tuyere structure can be realized at a low cost as compared with the case where the contractible mortar 10 is interposed over the entire area of the annular joint M of FIG. The low contractible mortar 11 can be configured as follows, for example.

  The refractory material for the low contractible mortar does not necessarily include silicon carbide powder, and may be composed of, for example, alumina powder or alumina-silica powder. In addition, the ceramic fiber is not included in the refractory material for the low contractible mortar, or the ceramic fiber included in the refractory material for the contractible mortar 10 when the ceramic fiber is included. It is preferable to make it less than the compounding amount. Specifically, when the blending ratio of the ceramic fiber in the refractory material for the contractible mortar 10 is X mass%, the blending ratio of the ceramic fiber in the refractory material for the low contractible mortar 11 is 0 to It is preferable that it is (X-10) mass%.

  Water may be used for the kneading liquid for the contractible mortar. However, if the amount of water is too large, the moisture in the low contractible mortar 11 oxidizes the silicon carbide powder in the contractible mortar 10 at the boundary between the low contractible mortar 11 and the contractible mortar 10. It is conceivable to let you. Therefore, when water is included in the kneading liquid for low-shrinkable mortar, the blending ratio is preferably less than 10% by mass in the kneading liquid for low-shrinkable mortar.

2 shows a tuyere structure according to a reference embodiment, and corresponds to a cross-sectional view taken along the line AA in FIG. In this reference form, the compressible mortar 10 is interposed over the entire area of the annular joint M between the tuyere body (Daimaru 1b) and the tuyere receiving refractory 2, and as described above Since the mortar 10 exhibits sufficient slag penetration resistance, the life of the tuyere structure can be extended as compared with the conventional tuyere structure.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this. For example, the configuration of the tuyere body is not limited to that shown in FIGS. The tuyere body has a concept including what is called a tuyere cooling box or a chilly. Moreover, the tuyere body does not have to have the Daimaru 1b. In this case, for example, the tuyere receiving refractory 2 surrounds the blower tuyere 1a. The tuyere receiving refractory 2 may be an unfired block in which an amorphous refractory such as alumina-silicon carbide or silicon carbide is cast, or may be fired brick. .

  Furthermore, in the said embodiment, although the example which applied the contractible mortar 10 to the tuyere structure was shown, the contractible mortar 10 can contact the molten slag of a blast furnace wall besides a tuyere structure. Can be widely used as position joint material.

Table 1 shows compositions and characteristic values of mortars A to F as one specific example. The unit of the numerical value of each item of the mortar composition is mass%. A blank in Table 1 means that the material is not included. As the ceramic fibers in Table 1, Al ₂ O ₃ accounted for 48 to 58% by mass, the balance was made of SiO ₂ , and the diameter was 2.5 μm. Monoethylene glycol and ethyl alcohol were both anhydrous with a concentration of 98% or more.

  Slag erosion resistance was evaluated by a rotary erosion tester. The lining of the drum was composed of a silicon carbide-based fired refractory, and the mortar samples A to F were filled in the grooves formed in the lining. Blast furnace slag was charged into the drum, and the drum was rotated while melting the blast furnace slag with a burner. Then, the erosion dimension of the maximum erosion part of each sample was measured, and each measured value was divided by the erosion dimension of the mortar D and indicated as a relative value (melting index). The erosion index indicates that the larger the value, the greater the erosion loss.

The shrinkage rate was measured according to the following procedure. A mortar sample is filled in a bottomed cylindrical crucible having an inner diameter of φ25 mm opened at the top. Then, the sample is sufficiently dried until the amount of the sample becomes constant, and the height L ₀ of the sample is measured at this stage. Next, with the sample in the crucible kept uniformly at 1200 ° C., a load of 1 MPa (about 10 kgf / cm ² ) was gently applied to the sample, and the sample height L ₁ when the compression amount of the sample was stabilized Read. Here, the contractibility is calculated as (L ₀ −L ₁ ) / L ₀ × 100.

  Table 2 also shows the compositions of the mortars A to F shown in Table 1 that were dried by heating at 500 ° C. for 2 hours in a reducing atmosphere. A blank in Table 2 means that the material is not included.

  As shown in Table 1, each of the mortars A to C exhibits excellent slag erosion resistance and contractibility. This is because silicon carbide powder, a specific configuration of alumina-siliceous ceramic fiber, and monoethylene glycol were used in combination. Since these mortars A to C are excellent in slag erosion resistance, the shrinkability can be prevented from being damaged due to slag infiltration, and the contractility necessary for preventing damage to the tuyere body can be exhibited over a long period of time. be able to. For this reason, it is suitable for use as the contractible mortar 10 of FIG.

  As shown in Table 1, the mortar D uses ethyl alcohol as the kneading liquid, and thus is inferior in slag erosion resistance and shrinkage rate compared to the mortars A to C. Moreover, as shown in Table 2, the amount of residual charcoal in the mortar D in a dry state is insufficient, and it is considered that the effect of forming a protective film on the ceramic fiber is inferior. From these points, it is considered that monohydric alcohol such as ethyl alcohol is not preferable as the kneading liquid of the contractible mortar 10 in FIG. 1, and polyhydric alcohol such as monoethylene glycol is preferable. This is because the monohydric alcohol volatilizes with almost no organic component remaining in the mortar. However, the mortar D can be used as the low contractible mortar 11 of FIG. In this case, the difference in contractibility between the low contractible mortar 11 and the mortars A to C as the contractible mortar 10 is 30% or more and 32% or less.

  The mortar E does not contain silicon carbide powder, is mainly composed of alumina powder, and water is used for the kneading liquid, so that the slag erosion resistance is insufficient. Since the mortar F was mainly composed of alumina powder, the slag erosion resistance was insufficient, and the blending amount of the ceramic fiber was too small, so that the contractibility was insufficient, and collapsed in the measurement of the contractibility.

Sectional drawing perpendicular | vertical to the furnace wall thickness direction of the tuyere structure by one Embodiment. Sectional drawing perpendicular | vertical to the furnace wall thickness direction of the tuyere structure by a reference form. Sectional drawing parallel to the furnace wall thickness direction of a tuyere structure by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... tuyere main body, 1a ... ventilation tuyere, 1b ... Daimaru, 1c ... ventilation branch, 2 ... tuyere receiving refractory material, 2a-2d ... split piece, 3 ... outer shell iron skin, 4 ... hearth wall refractory 5 ... Stave, 6 ... Conventional contractible mortar, 10 ... Contractable mortar (first refractory mortar), 11 ... Low contractible mortar (second refractory mortar), H ... Pore, M ... Ring joint, M ₁ ... lower arc joint, M ₂ ... upper arc joint

Claims (5)

It consists of a metal tuyere main body that is held on the furnace wall in a state of penetrating the blast furnace wall, and a tuyere receiving refractory that forms part of the furnace wall surrounding the tuyere main body. An annular joint that circulates along the outer peripheral surface of the tuyere body is secured between the main body and the refractory for receiving tuyere in a cross-sectional view perpendicular to the thickness direction of the furnace wall. Among them, a portion from the lower end of the total height of the truncated conical hole formed in the refractory for receiving tuyere to a height of 40% to 60% is a lower arc joint, and a portion above the upper arc joint is an upper arc joint. and then, the lower arcuate joint portion, is filled with a first refractory mortar with compressible properties, wherein the upper arcuate joint portion, a small second hot Allowed shrinkage than said first refractory mortar The tuyere structure of the blast furnace wall filled with refractory mortar.   2. The feather according to claim 1, wherein the difference between the contractibility of the first refractory mortar and the contractibility of the second refractory mortar when a compressive stress of 1 MPa is applied at a temperature of 1200 ° C. is 5% or more. Mouth structure. Said first refractory _mortar, Al 2 _{O 3} accounts for 40 to 60 mass%, and ceramic fiber the balance of predominantly SiO _2, mean particle according to claim 1 or 2, wherein and a diameter 100μm or less of silicon carbide powder Tuyere structure. In the first refractory mortar, Al ₂ O ₃ accounts for 40 to 60% by mass, the balance is mainly 30 to 80% by mass of ceramic fibers mainly composed of SiO ₂ , and silicon carbide powder having an average particle diameter of 100 μm or less is 10 to 60%. When 70 to 160% by mass of polyhydric alcohol is added to the refractory material containing 5% by mass and kneaded. After the construction, the dried molded body is subjected to a compressive stress of 1 MPa at a temperature of 1200 ° C. The tuyere structure according to claim 1, wherein the tuyere structure exhibits a contractibility of 30% or more. The first refractory mortar has a measurement of a dried molded article after construction. Al ₂ O ₃ accounts for 40 to 60% by mass, and the balance is mainly made of SiO ₂ 23 to 65% by mass, average particle diameter 100μm or less of silicon carbide powder 8-40 wt%, and residual carbon from 15 to 65 consist of mass%, when added to 1MPa compressive stress at a temperature of 1200 ° C., claims defining a compressible rate of over 30% The tuyere structure according to 1 .

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