JP2008156133A - Injection refractory under blast furnace body bottom plate, and construction method of blast furnace bottom - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water based injection refractory under a blast furnace body bottom plate which facilitates a construction, is low in treatment cost and can easily be recycled and used, and to provide a construction method of a blast furnace bottom. <P>SOLUTION: A high heat conductivity filler refractory containing ≥20 mass% SiC, 10-30 mass% graphite, ≤20 mass% Al<SB>2</SB>O<SB>3</SB>, ≤15 mass% SiO<SB>2</SB>and ≥95 mass% in total of SiC, graphite, Al<SB>2</SB>O<SB>3</SB>and SiO<SB>2</SB>as a chemical composition before water is added and having ≥4.5 W/m K heat conductivity at normal temperature is placed up to the height to form a certain gap between the upper surface and an installation level of the blast furnace main body bottom 3 to be in contact with a cooling pipe 7 arranged furnace bottom, the blast furnace main body bottom plate is mounted above the formed high heat conductivity filler layer 5 and after that, the injection refractory 6 for the blast furnace body bottom plate is injected into the gap between the blast furnace main body bottom plate and the high heat conductivity filler layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention promotes heat conduction by bringing these into close contact with a narrow space (hereinafter referred to as “gap”) between the bottom plate of the blast furnace main body and the high thermal conductivity filler layer constructed immediately below the bottom plate of the blast furnace main body. The present invention relates to a blast furnace main body bottom plate press-fitting material having a high thermal conductivity, and further to a method for constructing a blast furnace bottom using the blast furnace main body bottom plate lower press-fitting material.

  Various measures are applied to the bottom of the blast furnace in order to prevent the heat in the furnace from being transferred to the foundation concrete layer and to cool the refractory in the bottom of the furnace. For example, a method is known in which a cooling pipe is provided between the bottom of the blast furnace furnace and the foundation concrete layer, and heat from the furnace is taken out of the system by cooling water flowing through the cooling pipe. FIG. 2 shows an example proposed in Patent Document 1.

  In FIG. 2, a heat insulating layer 23 is provided between the foundation concrete layer 21 and the blast furnace main body bottom plate 22, and a high thermal conductivity filling layer 24 is formed between the blast furnace main body bottom plate 22 and the heat insulating layer 23. A cooling pipe 25 is embedded in the packed bed 24. By doing in this way, the heat from the furnace is efficiently taken out of the system by the cooling pipe 25. Moreover, the cooling pipe 26 is also arrange | positioned between the heat insulation layer 23 and the foundation concrete layer 21, and the heat transfer with respect to the foundation concrete layer 21 is suppressed. The bottom plate 22 of the blast furnace main body is supported by an I-type steel beam 27 to prevent a load from the refractory 28 and the iron shell 29 of the blast furnace from being directly applied to the cooling pipes 25 and 26.

  In such a furnace bottom structure, a graphite refractory is used as the high thermal conductivity filling layer 24 formed around the cooling pipe 25. That is, a graphite refractory is applied around the cooling pipe 25 with a rammer or the like to form the packed bed 24. In this case, since the construction is performed by a rammer or the like, the dimensional accuracy is not good and the area of the bottom plate 22 of the blast furnace body is extremely large. Therefore, the packed bed 24 is not in close contact with the bottom plate 22 of the blast furnace body. (Air gap) occurs. The thermal conductivity of the gap, that is, the air, is extremely low. Therefore, if a gap occurs, the heat conduction from the blast furnace body bottom plate 22 to the packed bed 24 is significantly hindered.

  Therefore, in order to prevent the formation of this gap, the packed bed 24 is constructed so that a gap of about several mm is generated between the bottom plate 22 of the blast furnace body and the packed bed 24, and graphite having high thermal conductivity is formed in this gap. The material press-fitting material is press-fitted from a pressure inlet provided in the blast furnace main body bottom plate 22. That is, conventionally, a graphite press-fit material has been used as the press-fit material under the bottom plate of the blast furnace main body.

  In order to increase the thermal conductivity to the maximum, the graphite press-fitting material has a high thermal conductivity of 97% by mass or more of its chemical components. Graphite has low wettability with water and cannot be sufficiently kneaded even with water. Therefore, a resin liquid and a hardening liquid are added to the graphite press-fit material in order to ensure kneadability. That is, the kneadability of the graphite press-fit material is ensured by the resin liquid and the curing liquid. The graphite press-in material is called “non-aqueous” because it does not use water.

  However, if the graphite press-fit material is press-fitted onto the filling layer 24 made of graphite refractory, the resin liquid contained in the graphite press-fit material is absorbed by the fill layer 24, and the flowability of the graphite press-fit material is reduced. In some cases, the graphite press-in material may not be filled in the gap between the blast furnace main body bottom plate 22 and the packed bed 24, or a bubble may be generated in the press-fit layer of the graphite press-fit material. In such a case, as in the case where the gap is generated, the thermal conductivity is lowered and the desired cooling cannot be performed.

Therefore, in Patent Document 2, in order to ensure the fluidity at the time of construction of the graphite press-fitting material, an early-hardening graphite iron coating material is applied on the filling layer 24, and the graphite press-fitting material is injected thereon. Propose that. According to Patent Document 2, the fast-curing graphite iron coating material hardens in about 1 hour after construction, and a smooth layer having a resin film formed on the surface is formed. Is going to be done.
JP-A-56-23204 Japanese Patent Laid-Open No. 2-145714

  According to the above-mentioned Patent Document 2, problems during the press-fitting of the graphite press-fitting material are greatly reduced. However, Patent Document 2 basically has a problem in that a non-aqueous graphite press-fitting material is used as the blast furnace main body bottom plate press-fitting material.

  That is, the viscosity of the resin liquid added to the graphite pressing material, that is, the flow characteristics of the graphite pressing material is easily influenced by the temperature. There is a risk of occurrence of the occurrence of an increase in the curing time of the material. As a result, the construction process is extended and the production impact and cost increase are inevitable. Even if the graphite press-fit material is heated before construction, the effect cannot be expected because of the lack of absolute heat capacity and difficulty in uniform temperature control. Also, the disposal of the remaining graphite press-in material is “non-aqueous”, so it is necessary to request disposal to a specific industrial waste disposal company. There is also a problem that the burden is heavy.

  The present invention has been made in view of such circumstances, and its object is to have a thermal conductivity equivalent to that of a conventional non-aqueous graphite press-fit material, which is easy to construct and has poor filling, etc. In addition, it is possible to provide a water-based blast furnace main body bottom plate press-fitting material in place of a non-aqueous graphite press-fitting material that is low in processing cost and can be recycled. It is to provide a method for constructing a blast furnace bottom using a lower press-fitting material.

In the blast furnace main body bottom plate press-fitting material according to the first invention for solving the above-mentioned problems, the chemical composition before adding water is SiC: 20 mass% or more, graphite: 10-30 mass%, Al ₂ O ₃ : 20% by mass or less, SiO ₂ : 15% by mass or less, and the total content of SiC, graphite, Al ₂ O ₃ and SiO ₂ is 95% by mass or more, and the thermal conductivity at room temperature is 4.5W. / M · K or more.

  The method for constructing the blast furnace bottom according to the second invention is such that the high thermal conductivity filler refractory has a bottom surface of the blast furnace body up to a height at which the upper surface forms a slight gap with the installation level of the blast furnace body bottom plate. A high thermal conductivity filler layer is formed by contact with a cooling pipe disposed in the upper surface, and then a blast furnace body bottom plate is installed above the formed high thermal conductivity filler layer, and then the blast furnace body bottom plate and The blast furnace main body bottom plate press-fitting material described in the first invention is press-fitted into a gap with the high thermal conductivity filler layer.

  According to the blast furnace main body bottom plate press-fitting material according to the present invention having the above composition, although it is a water-based press-fitting material, it is possible to obtain a thermal conductivity equivalent to that of a conventional non-aqueous graphite press-fitting material. Can cool the bottom of the blast furnace with the same efficiency. In addition, since the blast furnace main body bottom plate press-fitting material according to the present invention is water-based, the flow characteristics at the time of press-fitting are good, and it can be quickly and easily press-fitted into a narrow gap under the blast furnace main body bottom plate without forming bubbles or gaps. be able to. Furthermore, since it is water-based, even if it is disposed of, the cost is not only low, but it can be diverted to refractories for dredging blast furnace cast floors, etc. Compared to water-based graphite press-fitting material, it can be greatly reduced. In addition, since it is water-based, the time spent for curing can be controlled according to the temperature, so that it is possible to avoid extending the construction time and shorten the process.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic sectional view showing the structure of a blast furnace bottom to which the present invention is applied. FIG. 1 shows only one side from the center of the blast furnace bottom.

  As shown in FIG. 1, when installing the blast furnace main body 1, first, a foundation concrete layer 4 having sufficient strength to hold the blast furnace main body 1 is applied to the ground. On this foundation concrete layer 4, the blast furnace body iron skin 2 constituting the outer shell of the blast furnace body 1 is installed, and the blast furnace body iron skin 2 is fixed to the foundation concrete layer 4 by anchor bolts 9 reaching the foundation concrete layer 4. Next, the secondary concrete layer 12 is applied on the foundation concrete layer 4 so that the secondary concrete layer 12 is fitted to the bottom of the blast furnace body iron skin 2. Before or after installation of the blast furnace body skin 2, the I-type steel beam 11 is disposed on the secondary concrete layer 12 and at a certain distance from the secondary concrete layer 12 above the secondary concrete layer 12. The secured cooling pipe 7 for letting cooling water pass is arranged. Thereafter, a high thermal conductivity filler refractory is applied to the gap between the cooling pipe 7 and the secondary concrete layer 12 to form the high thermal conductivity filler layer 10.

  Thereafter, in a state where the high thermal conductivity filler layer 10 and the cooling pipe 7 are in contact with each other, a high thermal conductivity filler refractory is applied on the high thermal conductivity filler layer 10 to form the high thermal conductivity filler layer 5. To do. As the high thermal conductivity filler refractory for forming the high thermal conductivity filler layer 5 and the high thermal conductivity filler layer 10, a conventional graphite stamp material or SiC castable which is an irregular refractory can be used. . In the construction of the high thermal conductivity filler layer 5, it is preferable to adjust so that the gap from the installation level of the blast furnace body bottom plate 3 installed thereafter is about 0.5 to 5 mm.

  After the applied high thermal conductivity filler layer 5 is cured, the blast furnace body bottom plate 3 is installed at a predetermined position above the high thermal conductivity filler layer 5. At that time, the blast furnace main body bottom plate 3 is integrally joined to the blast furnace main body iron core 2 and the I-shaped steel beam 11 by welding or the like. The blast furnace main body bottom plate 3 is provided with a plurality of pressure inlets 8 for press-fitting the blast furnace main body bottom plate press-fitting material 6. After the blast furnace main body bottom plate 3 is attached to the blast furnace main body core 2 and the I-shaped steel beam 11, the water-based blast furnace main body bottom plate lower press-fitting material 6 according to the present invention is formed between the blast furnace main body bottom plate 3 and the high thermal conductivity filler layer 5. And the bottom of the blast furnace body 1 is constructed.

  Here, the water-based blast furnace main body bottom plate press-fitting material 6 according to the present invention will be described.

In the blast furnace main body bottom plate press-fitting material 6 according to the present invention, chemical components before adding water are SiC: 20% by mass or more, graphite: 10-30% by mass, Al ₂ O ₃ : 20% by mass or less, SiO ₂ : 15% by mass or less, the total content of SiC, graphite, Al ₂ O ₃ and SiO ₂ is 95% by mass or more, and the thermal conductivity at room temperature is 4.5 W / m · K or more. Is required.

  The blast furnace main body bottom plate press-fitting material 6 according to the present invention is water-based, and is press-fitted into a gap between the blast furnace main body bottom plate 3 and the high thermal conductivity filler layer 5, and the heat of the blast furnace main body bottom plate 3 is transferred to the high thermal conductivity filler. Since it is necessary to have a function of positively transmitting to the layer 5, it is necessary to have a high thermal conductivity. Therefore, as a main raw material of the bottom press-fitting material 6 of the blast furnace body bottom plate, SiC that can be kneaded with water and has a high thermal conductivity is used for the purpose of increasing the thermal conductivity. Graphite which is a main component of the water-based press-fitting material was added.

  However, in order to use an aqueous system, it is necessary to limit the blending amount of graphite. As a result of various studies, it was found that if graphite is 30% by mass or less, kneading with water is possible. If graphite is not blended, it becomes easily water-based. However, utilizing the high thermal conductivity of graphite is effective for the blast furnace main body bottom plate press-fitting material 6, and therefore, graphite is blended in an amount of 10% by mass or more. And since the compounding quantity of graphite was restrained, the compounding quantity of SiC was 20 mass% or more for the purpose of ensuring heat conductivity. Furthermore, in order to ensure heat conductivity, it is preferable to contain 60 mass% or more of SiC. It was found that by blending in this way, high thermal conductivity can be ensured even in an aqueous system. As the graphite raw material, a conventional graphite raw material such as phosphorus-like graphite, soil graphite, carbon black, and artificial graphite may be used. As a raw material of SiC, SiC having a relatively high purity manufactured industrially from metal Si or the like is used.

Al ₂ O ₃ and SiO ₂ are components constituting clay, and the addition of Al ₂ O ₃ and SiO ₂ further facilitates kneading with water. However, Al ₂ O ₃ and SiO ₂ are close to heat insulators, and the thermal conductivity of the blast furnace main body bottom plate press-fitting material 6 decreases as the amount of these increases. Therefore, the blending amount of Al ₂ O ₃ is set to 20% by mass or less, and the blending amount of SiO ₂ is set to 15% by mass or less. From the viewpoint of thermal conductivity, the blending amount of Al ₂ O ₃ is more preferably 15% by mass or less, and the blending amount of SiO ₂ is 10% by mass or less. As the Al ₂ O ₃ source and the SiO ₂ source, individual raw materials such as alumina powder and quartzite powder may be used, and a raw material of a compound of Al ₂ O ₃ and SiO ₂ such as mullite and kaolinite. May be used. In order to improve the kneadability with water, it is preferable to use a raw material of a compound of Al ₂ O ₃ and SiO ₂ .

  Furthermore, it is essential that the blast furnace main body bottom plate press-fitting material 6 according to the present invention has a thermal conductivity of 4.5 W / m · K or more at room temperature. However, if it is in the range of the above chemical components, generally, the thermal conductivity at room temperature is 4.5 W / m · K or more.

  The blast furnace main body bottom plate press-fitting material 6 according to the present invention is a water-based press-fitting material, and water is released during drying after construction. This water does not pose a problem because it penetrates into the lower foundation concrete layer 4 or a plurality of pressure inlets 8 provided on the bottom plate 3 of the blast furnace body serve as deaeration ports and are discharged from the pressure inlets 8. .

  In the case of non-aqueous graphite press-fitting materials, a curing solution is used to adjust the curing time, but the curing time is mainly related to the temperature dependence of the resin solution, especially in winter. It is difficult to grasp. In contrast, in the water-based blast furnace main body bottom plate press-fitting material 6 of the present invention, a curing time adjusting agent (a curing accelerator and a retarding agent) can be used in the same manner as a general castable. By using it, there is an advantage that the curing time can be adjusted without being affected by the raw material temperature or the climate.

  That is, the water-based blast furnace main body bottom plate press-fitting material 6 according to the present invention is press-fitted into the gap between the blast furnace main body bottom plate 3 and the high thermal conductivity filler layer 5, and the press-fitted layer of the blast furnace main body bottom plate lower press-fitting material 6 is inserted into this gap. By forming (not shown), it is possible to obtain a thermal conductivity equivalent to that of a conventional non-aqueous graphite press-in material even though it is a water-based press-fit material, and with the same efficiency as the conventional blast furnace The main body bottom plate 3 can be cooled. In addition, since it is water-based, it has good flow characteristics at the time of press-fitting, quickly and easily ensuring high thermal conductivity without forming bubbles or gaps, and in a narrow gap below the bottom plate 3 of the blast furnace body. It can be press-fitted and the construction period can be greatly shortened.

  In addition, since it is aqueous, it is easier to handle than non-aqueous, and even if it is disposed of, its cost is not only low, but it can be used for refractories for dredging in blast furnace cast floors as long as the composition is as described above. Can be diverted, and the processing cost of the remaining material can be greatly reduced compared to the conventional non-aqueous system. Furthermore, the conventional graphite press-fitting material itself is extremely expensive, but the blast furnace main body bottom plate lower press-fitting material 6 of the present invention can greatly reduce the price as compared with the graphite press-fitting material.

In the blast furnace main body having a capacity of 5000 Nm ³ class shown in FIG. 1, the blast furnace bottom was constructed using the blast furnace main body bottom plate press-fitting material of the present invention.

The components of the press-fitted material under the bottom plate of the blast furnace main body used were SiC: 60% by mass, graphite: 15% by mass, Al ₂ O ₃ : 15% by mass, SiO ₂ : 8% by mass, and the thermal conductivity at room temperature was 5. 2 W / m · K. When about 6 hours passed after the completion of the press-fitting, it was confirmed that the hardening of the press-fitted material under the bottom plate of the blast furnace main body was completed. When a conventional non-aqueous graphite press-fit material (graphite: 97% by mass) is used, it takes 2-3 days to carry out burner heating until it hardens, which can greatly shorten the construction period. did it.

It is a schematic sectional drawing which shows the structure of the blast furnace furnace bottom to which this invention is applied. It is a schematic sectional drawing which shows the structure of the conventional blast furnace bottom.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blast furnace main body 2 Blast furnace main body core 3 Blast furnace main body bottom plate 4 Foundation concrete layer 5 High thermal conductivity filler layer 6 Blast furnace main body bottom plate press-fit material 7 Cooling pipe 8 Inlet 9 Anchor bolt 10 High thermal conductivity filler layer 11 I-type steel beam 12 Secondary concrete layer

Claims (2)

Chemical components before adding water are SiC: 20% by mass or more, graphite: 10-30% by mass, Al ₂ O ₃ : 20% by mass or less, SiO ₂ : 15% by mass or less, and SiC, graphite, A blast furnace main body bottom plate lower press-fit material, wherein the total content of Al ₂ O ₃ and SiO ₂ is 95% by mass or more, and the thermal conductivity at room temperature is 4.5 W / m · K or more.   A high heat conductivity filler refractory is applied in contact with the cooling pipe located on the bottom of the blast furnace body until the top surface forms a slight gap with the installation level of the bottom plate of the blast furnace body. Forming a conductivity filler layer, then installing a blast furnace body bottom plate above the formed high thermal conductivity filler layer, and thereafter, in a gap between the blast furnace body bottom plate and the high thermal conductivity filler layer, A method for constructing a blast furnace bottom, which comprises press-fitting the blast furnace main body bottom plate press-fitting material according to 1.

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