JP6432234B2 - Inorganic fiber insulation block manufacturing method - Google Patents

Description

  The present invention relates to an inorganic fibrous heat insulating material block used for lining in a furnace and a method for producing the same. Moreover, this invention relates to the furnace provided with this inorganic fibrous heat insulating material block.

  Conventionally, heavy refractories such as steel plates and bricks have been often used for furnace wall lining in the furnace. In recent years, the use of inorganic fiber heat insulating materials having excellent operability and energy saving properties such as high heat insulating properties, high thermal shock resistance, and rapid temperature rise / fall is increasing.

  As an example, use as a lining material for a member that is in direct contact with a molten metal, such as a ladle made of zinc or aluminum, has been studied. Since the inorganic fibrous heat insulating material block is excellent in heat insulating properties, when used for a ladle lining, it is possible to prevent a temperature drop of the ladle. Moreover, since the inorganic fibrous heat insulating material block is lightweight, the structure of the iron skin and the refractory material constituting the ladle can be simplified.

  The use of inorganic fiber insulation is expanding in various annealing furnaces. When using an inorganic fiber heat insulating material block for an annealing furnace, it is desired to have a configuration in which mixing of oxygen and moisture is prevented in the furnace. In particular, in an annealing furnace for continuous galvanization, it takes a long time to replace the air and moisture contained in the inorganic fiber heat insulating material with an inert gas such as nitrogen. Therefore, there is an inorganic fiber heat insulating material that can reduce the time required for gas replacement. It has been sought after because of the great merit of shortening the shutdown time.

  Patent Document 1 discloses a molded body formed by bonding ceramic fibers with an organic and inorganic binder, and a fiber having a gas-impermeable coating on at least one surface perpendicular to the in-furnace lining direction of the molded body. A quality molded body is described. This coating material is formed by applying a composition containing a refractory aggregate powder such as silica stone, a glass material powder, and an alkoxide sol by spraying or the like, drying, and heat-treating at 1000 to 1200 ° C.

Patent Document 2 describes a ceramic fiber block compression-molded at 50 to 350 kg / cm ³ as a refractory material for a lining of a hot-dip galvanizing facility.

  In Patent Document 3, for the purpose of reducing fiber scattering from the surface of an inorganic fiber molded body, a silica alumina fiber is molded with an inorganic binder and an organic binder, and the surface includes a coating material containing inorganic fibers, inorganic particles, and an organic binder. An inorganic fiber molded body coated with is described.

JP-A-8-239257 JP 2002-121658 A JP 2001-278680 A

  In Patent Documents 1 and 3, there is a high possibility that the coating layer on the surface melts and peels off when the temperature in the furnace is high or when the furnace is used for a long time. Further, when the block is used as a block on the bottom surface that receives the molten metal, there is a possibility that cracks may occur in the coating layer due to mechanical shock or thermal shock.

  In Patent Document 2, there is a concern that the molten metal permeates into the gaps of the ceramic fiber blocks or the contact portions (joint portions) between the ceramic fiber blocks and erodes the iron skin and the like. In addition, since the ceramic fiber block has a high porosity, there is a problem that much labor is required to replace oxygen and water vapor inside the ceramic fiber block with a stabilizing gas such as nitrogen.

  The present invention has a high barrier property against gas components such as water vapor, is excellent in heat resistance, is excellent in mechanical and thermal shock properties, an inorganic fiber heat insulating block, a method for producing the same, It aims at providing the furnace provided with the inorganic fiber molded object.

  The inorganic fiber heat insulating material block of the present invention is an inorganic fiber heat insulating material block used for lining construction of a surface to be heated in a furnace, and includes at least a first inorganic fiber aggregate layer, a second inorganic fiber aggregate layer, and those And a gas barrier layer provided between the first inorganic fiber assembly layer and the opposite surface of the first inorganic fiber assembly layer to the inside of the furnace.

  This gas barrier layer is preferably made of a fired glaze.

  The manufacturing method of the inorganic fibrous heat insulating material block of the present invention includes a step of applying a glaze to one surface of the first inorganic fiber aggregate layer and the second inorganic fiber aggregate layer, and the first inorganic fiber aggregate The one surface of the layer and the second inorganic fiber aggregate layer are brought into contact with each other and fired to form a gas barrier layer between the first inorganic fiber aggregate layer and the second inorganic fiber aggregate layer. It has a process.

  The furnace of the present invention is provided with the inorganic fibrous heat insulating material block of the present invention as a furnace lining.

  The inorganic fibrous heat insulating material block of the present invention has a gas barrier layer and is excellent in gas barrier properties. In the present invention, since the gas barrier layer is provided between the first inorganic fiber assembly layer and the second inorganic fiber assembly layer, the gas barrier layer does not directly contact the furnace atmosphere. Therefore, the durability of the gas barrier layer is good.

  Since most of the first and second inorganic fiber aggregate layers are made of an inorganic fiber material, the inorganic fibrous heat insulating material block of the present invention is lightweight and easy to handle, and preheating at the time of temperature rise is also possible. It is unnecessary.

  According to the production method of the present invention, it is possible to easily produce inorganic fibrous heat insulating material blocks having various sizes and shapes.

It is sectional drawing of the inorganic fibrous heat insulating material block which concerns on embodiment. It is sectional drawing which shows an example of the manufacturing method of an inorganic fibrous heat insulating material block.

  Hereinafter, although embodiment of this invention is described, this invention is not limited to the following description. FIG. 1 is a cross-sectional view showing an example of the inorganic fibrous heat insulating material block of the present invention. The inorganic fibrous heat insulating material block 4 has at least a first inorganic fiber aggregate layer 1 and a second inorganic fiber aggregate layer 2 as inorganic fiber aggregate layers, and the first inorganic fiber aggregate layer 1 A gas barrier layer 3 is provided between the second inorganic fiber aggregate layer 2. This inorganic fiber heat insulating material block 4 is used for lining the heated surface in the furnace so that the first inorganic fiber aggregate layer 1 is on the furnace inner side and the second inorganic fiber aggregate layer is on the furnace wall side. Used.

  The material of the first inorganic fiber aggregate layer 1 and the second inorganic fiber aggregate layer 2 is not particularly limited, but preferably the first inorganic fiber aggregate layer 1 is alumina having excellent heat resistance. / It consists of a silica fiber blanket. The second inorganic fiber aggregate layer 2 may be a ceramic fiber blanket or an alumina / silica fiber blanket, but the same material as that of the first inorganic fiber aggregate layer 1 is preferred to form a uniform gas barrier layer 3. Each of the inorganic fiber aggregate layers 1 and 2 may be composed of one blanket, or may be a laminate of a plurality of blankets.

  The composition ratio (mass ratio) of alumina / silica fiber in the alumina / silica fiber is preferably in the range of 65 to 98/35 to 2 called mullite composition or high alumina composition, more preferably 70 to 95/30 to 5, particularly preferably in the range of 70 to 74/30 to 26.

  The inorganic fibers constituting the inorganic fiber aggregate are preferably 80% by mass or more, more preferably 90% by mass or more, and particularly the total amount thereof is polycrystalline alumina / silica fiber having the above mullite composition.

  The inorganic fibers in the inorganic fiber aggregate are preferably substantially free of fibers having a fiber diameter of 3 μm or less. Here, “substantially free of fibers having a fiber diameter of 3 μm or less” means that the fibers having a fiber diameter of 3 μm or less is 0.1 mass% or less of the total inorganic fiber mass.

  Moreover, it is preferable that the average fiber diameter of an inorganic fiber is 5-7 micrometers. If the average fiber diameter of the inorganic fibers is too large, the repulsive force and toughness of the mat-like inorganic fiber aggregate will be reduced. The probability of containing inorganic fibers increases.

  Inorganic fiber aggregates having the above-mentioned preferred average fiber diameter and substantially free of inorganic fibers having a fiber diameter of 3 μm or less are used in the production of inorganic fiber aggregates by the sol-gel method. It can be obtained by controlling the air flow used for the nozzle and controlling the drying of the drawn yarn.

  The shot rate of the inorganic fiber aggregate is not particularly limited, but is usually 7% or less, preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less.

  The gas barrier layer 3 is not particularly limited but is preferably made of a fired glaze.

  In order to manufacture this inorganic fiber heat insulating material block 1, only one side of each of the first and second inorganic fiber aggregate layers 1 and 2 or one side of the inorganic fiber aggregate layers 1 and 2 is used. After the glaze slurry is applied and dried to form the dried glaze slurry layer 3a, the glaze application surfaces of the inorganic fiber assembly layers 1 and 2 or the glaze application layer and the inorganic fiber assembly layer surface are brought into contact with each other, As shown in FIG. 2, the glaze slurry is applied to one surface of each of the first and second inorganic fiber aggregate layers 1 and 2 and dried to form a dried glaze slurry layer 3a as shown in FIG. After that, it is more desirable that the glaze application surfaces of the inorganic fiber aggregate layers 1 and 2 are brought into contact with each other and fired.

  As a glaze slurry, what was prepared by mixing a fireproof aggregate powder, glass material powder, water, and a thickener is preferable.

  As the refractory aggregate powder, one or more of quartzite, rholite, chamotte, mullite, alumina and the like can be used. The particle size of the refractory aggregate powder is preferably 100 μm or less, and more preferably contains a large amount of 44 μm or less. Further, the particle size distribution peak of the refractory aggregate powder is preferably 5 μm or more and 30 μm or less.

  As the glass material powder, frit, borosilicate glass, or the like can be used. The particle size of the glass material powder is desirably 300 μm or less, and is preferably 44 μm or more in view of the workability of the coating material. Moreover, it is preferable that the particle size distribution peak of glass material powder is 60 micrometers or more and 200 micrometers or less.

  The thickener may be an organic thickener such as carboxymethyl cellulose or dextrin, or may be an inorganic thickener such as bentonite.

  The mixing ratio of the refractory aggregate powder and the glass material powder is preferably 90 to 60% by weight of the refractory aggregate powder and 10 to 40% by weight of the glass material powder. When the glass material powder is less than 10% by weight, a dense structure having poor gas permeability cannot be obtained, and when it exceeds 40% by weight, heat resistance cannot be obtained.

The fire resistance may be adjusted by using a plurality of glaze powders having different fire resistance. Moreover, you may adjust a fire resistance by changing the ratio of the alkali metal and alkaline-earth metal in a glaze. Glaze with high fire resistance has a low mixing ratio of alkali metal and alkaline earth, and is often a crystalline substance. The chemical composition of the glaze _{aR 2 O · bAO · xAl 2} O 3 · ySiO 2 (R: alkali metal, A: alkaline earth metal) when expressed as a fluidity of the glaze was melted and _{R 2} O and AO often Becomes higher. Effect on R ₂ O and AO and liquidity Trip _{R 2} O is large.
Further, as the components of the refractory aggregate, the total of Al ₂ O ₃ and SiO ₂ is 60% by weight or less, the R ₂ O is 5% by weight or less, the AO is 9% by weight or less, and glass As a component of the material, the total of Al ₂ O ₃ and SiO ₂ is 65% by weight or less, the R ₂ O is 10% by weight or less and the AO is 10% by weight or less. Use of a glass material is preferable in that the glaze layer can be formed uniformly when the glaze layer is formed in the intermediate layer between the alumina fiber layers.

  The glaze slurry is preferably applied to the inorganic fiber molded body by brush coating, spraying or the like. After applying the glaze slurry, it is desirable to dry at 110 ° C. for about 30 minutes or more. By drying in this way, it is possible to suppress the destruction of the structure of the gas barrier layer accompanying the movement of moisture that occurs during heating.

  After the drying, the coated surfaces of the first and second inorganic fiber molded bodies 1 and 2 are brought into contact with each other (for example, superimposed) and fired. The firing conditions are preferably maintained at 800 to 1300 ° C., particularly 900 to 1200 ° C., for 1 to 5 hours, particularly 2 to 4 hours. By this firing, an inorganic fibrous heat insulating material block 4 having a structure in which the gas barrier layer 3 is sandwiched between the inorganic fiber aggregate layers 1 and 2 is obtained.

  In order to make the gas barrier layer 3 formed by applying such glaze slurry, drying and firing dense, the inorganic fiber aggregate layers 1 and 2 are impregnated and supported by an inorganic sol such as alumina sol. preferable. If the inorganic fiber aggregate is not impregnated with the inorganic sol, the glass component in the molten glaze will move to the fiber gap (about 45 μm) of the inorganic fiber aggregate due to the capillary phenomenon during firing, and the gas barrier layer will be uneven. In some cases, small holes may be formed in the gas barrier layer.

  The supported amount of the inorganic sol is preferably about 10 to 30 g, particularly about 15 to 25 g as a solid content per 100 parts by weight of the inorganic fiber molded body. In order to carry the inorganic sol on the inorganic fiber aggregate, the inorganic fiber aggregate may be dipped in the inorganic sol and then dried, but is not limited thereto.

  When this inorganic fiber heat insulating material block 4 is used as a lining material in an industrial furnace, the heat load applied to the gas barrier layer 3 is low, so that the gas barrier layer 3 is difficult to melt and the temperature difference from the back surface is reduced. It becomes difficult to break.

  Hereinafter, embodiments of the present invention will be described in detail. The following description is a representative example of the embodiment of the present invention, and the present invention is not limited to these contents unless it exceeds the gist. In addition, the physical-property measurement and evaluation method of the inorganic fibrous heat insulating material block obtained in the following examples etc. are as follows.

[Water vapor permeability]
A sample is cut into a size of 50 mm × 50 mm, and its weight W ₁ (g) is measured. 10 g of dried calcium chloride is placed in a 10 mm deep aluminum container having an opening of 50 mm × 50 mm, and the sample is placed in the opening. Thereafter, the joint between the sample and the side surface of the container is completely enclosed with aluminum tape to obtain a test specimen. This specimen is placed in a constant temperature and humidity chamber having a temperature of 23.0 ° C. and a relative humidity of 75%. After 40 hours, the sample is removed from the container and its weight W ₂ (g) is measured. Water vapor transmission rate ^T a ^(g / m 2 / ^40hr) is calculated by the following equation.

T = (W ₂ −W ₁ ) / (0.05 * 0.05)
If T is less than 100 g / m ² (however, the thickness is 21 mm and per 40 hr), it is determined to be good.

[Thermal shock resistance]
Samples are cut to a size of 50 mm x 50 mm. Next, the sample is placed in an electric furnace in which the furnace temperature is set to the glaze firing temperature + 100 ° C. Remove after heating for 15 minutes and air cool for 15 minutes. This heating / air cooling cycle is repeated three times, and the presence or absence of cracks is visually observed.

Further, the water vapor permeability of the sample after the heating / air cooling (3 cycles) treatment is measured, and the thermal shock resistance is evaluated by the amount of change in the water vapor permeability before and after the heating / air cooling (3 cycles) treatment. Here, when T = less than 100 g / m ² and the ratio of the water vapor permeability after the heating / air cooling treatment to the water vapor permeability before the heating / air cooling treatment is less than 1.2, it is determined that the thermal shock resistance is good. Is done.

[Example 1]
Two alumina fiber blankets (Maftec (registered trademark) MLS-2, thickness 10 mm, manufactured by Mitsubishi Plastics, Inc.) were cut into a size of 50 mm × 50 mm. Thereafter, each cut blanket was impregnated with alumina sol (Nissan Chemical Co., Ltd. AS200) by an immersion method. Then, it dehydrated with a blower at a pressure of 20 kPa for 5 minutes, and dried at 110 ° C. for 30 minutes while sucking to obtain an inorganic fiber aggregate. The supported amount was 20 g as a solid content per 100 g of the blanket.

  Also, 100 parts by weight of refractory aggregate (Fukushima Gyaku Co., Ltd., Lime Kashi No. 1), 70 parts by weight of glass component (Fukushima Gyaku Co., Ltd., lead-free frit), and 1.4 parts by weight of chemical paste (Fukushima Gyaku Co., Ltd. carboxymethyl cellulose) Further, 110 parts by weight of water was added to prepare a glaze slurry.

  This glaze slurry was applied to one surface of each of the above inorganic fiber aggregates by 2.5 g as a solid content (5.0 g in total) and dried at 110 ° C. for 3 hours. Thereafter, as shown in FIG. 2, the glaze-coated surfaces of the two inorganic fiber aggregates are overlapped with each other, heated at 5 ° C./min, held at 1000 ° C. for 3 hours, and cooled at 5 ° C./min. As shown, an inorganic fibrous insulation block having a gas barrier layer therein was produced.

  About this inorganic fibrous heat insulating material block, water vapor permeability and thermal shock resistance were evaluated as described above. The results are shown in Table 1.

[Example 2]
In Example 1, one of the two alumina fiber blankets was the same as Example 1 except that one was a ceramic fiber blanket (Isolite Industry Co., Ltd. Isowool 1260 Blanket 8P12.5T, thickness 12.5 mm). An inorganic fibrous insulation block was produced. Table 1 shows the results of evaluation of water vapor permeability and thermal shock resistance.

[Comparative Example 1]
Two alumina sol-impregnated alumina fiber blankets prepared in the same manner as in Example 1 were cut into a size of 50 mm × 50 mm. Thereafter, 5.0 g of the glaze slurry as a solid content was applied only to one surface of the first alumina fiber blanket, and no glaze slurry was applied to the second alumina fiber blanket. And the inorganic fiber heat insulating material block was manufactured like Example 1 except having piled up the other side of the 1st alumina fiber blanket on the 2nd alumina fiber blanket, and baking. The evaluation results of water vapor permeability and thermal shock resistance are shown in Table 1.

[Comparative Example 2]
Two pieces of alumina fiber blanket (Maftec (registered trademark) MLS-2, thickness 10 mm) manufactured by Mitsubishi Plastics Co., Ltd. are cut out into a size of 50 mm × 50 mm, overlapped without applying glaze slurry, and a pair of inorganic fibers A quality insulation block. Table 1 shows the results of evaluation of water vapor permeability and thermal shock resistance.

[Comparative Example 3]
Two alumina sol-impregnated alumina fiber blankets produced in the same manner as in Example 1 were cut out to a size of 50 mm × 50 mm and overlapped without applying glaze slurry to form a pair of inorganic fiber heat insulating material blocks. Table 1 shows the results of evaluation of water vapor permeability and thermal shock resistance.

  From Table 1, it is recognized that the inorganic fibrous heat insulating material block of the present invention has a low water vapor permeability and excellent thermal shock resistance.

DESCRIPTION OF SYMBOLS 1 1st inorganic fiber molded object 2 2nd inorganic fiber molded object 3 Glaze fired material 3a Glaze slurry dried material layer 4 Inorganic fiber heat insulating material block

Claims (1)

Applying glaze to one surface of the first inorganic fiber aggregate layer and the second inorganic fiber aggregate layer;
The one surface of the first inorganic fiber aggregate layer and the second inorganic fiber aggregate layer are brought into contact with each other and fired to form a first inorganic fiber aggregate layer and a second inorganic fiber aggregate layer. A process for forming a gas barrier layer between the inorganic fibrous heat insulating material blocks,
The first inorganic fiber aggregate layer has an alumina / silica-based inorganic fiber, and the alumina / silica-based inorganic fiber has an alumina / silica composition ratio of 65 to 98/35 to 2,
A method of manufacturing an inorganic fiber heat insulating material block, wherein the first and second inorganic fiber aggregate layers are impregnated with and supported by an inorganic sol.

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