JP2003292383A - Manufacturing method for monolithic refractory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a monolithic refractory which excels in thermal shock resistance, dry crack resistance, and productivity, and particularly which can suitably be used as a material directly contacting with a molten metal. <P>SOLUTION: This method comprises the first step of preparing a slurry by optionally adding and mixing water into a composition for making the monolithic refractory which consists of 5-10 mass% as solids of an inorganic binder, 77-93 mass% of a heat resistant fine powder, and 3-13 mass% of an inorganic fiber and the second step of casting the above slurry into a mold of a desired shape, drying the slurry, curing it, and demolding. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an irregular shaped refractory material, and more specifically, it has excellent thermal shock resistance, dry crack resistance, and productivity, and is particularly suitable for use as a material in direct contact with molten metal. The present invention relates to a method for manufacturing an irregular shaped refractory material that can be obtained.

[0002]

2. Description of the Related Art Conventionally, various types of amorphous refractories have been proposed, for example, amorphous refractories intended for direct contact with molten metal. For example, Japanese Patent Laid-Open No. 61-215627 discloses an indefinite shape for molten metal containing a base material containing zircon and silica as main components, coarse aggregate particles of the same quality as the base material, and a siliceous chemical binder. Refractory materials have been proposed. Further, in JP-A-57-206548, a fibrous mold composition comprising a mud-like slurry obtained by dispersing and suspending fine powder of a heat-resistant material and inorganic fibers in a hydrolyzing solution of colloidal silica or ethyl silicate. Is proposed.

However, JP-A-61-215627
The amorphous refractory for molten metal containers described in Japanese Patent Publication has a drawback that it is poor in thermal shock resistance and corrosion resistance and cracks easily occur in the refractory during use. Further, since coarse aggregate particles having a diameter of 10 mm or more are used, it is impossible to manufacture a spout of a low melting point aluminum melt having a thickness of 10 to 15 mm, for example. Further, the technique described in JP-A-57-206548 is such that a fibrous mold composition prepared on a wax mold is coated, dried (3 hours), and the coating and drying steps are repeated for 5 to 5 times. Since the process of dewaxing after forming 6 layers is adopted, there is a drawback that the process is complicated and the productivity is poor. Also, thermal shock resistance,
It also has the drawback of poor corrosion resistance and cracking of refractories during use.

[0004]

Therefore, the object of the present invention is to provide excellent heat shock resistance, dry crack resistance and productivity.
In particular, it is to provide a method for producing an amorphous refractory material that can be suitably used as a material that comes into direct contact with molten metal.

[0005]

According to the present invention, the inorganic binder is 5 to 10% by mass as a solid content, and the heat resistant fine powder 77 to
If necessary, water is added to and mixed with a composition for producing an amorphous refractory material consisting of 93% by mass and 3 to 13% by mass of inorganic fibers, and a first step of preparing a slurry, and the slurry having a desired shape. Pour into mold, dry and harden, and remove from mold 2
The present invention provides a method for manufacturing an amorphous refractory material, which comprises: Further, the present invention provides the above-mentioned method for producing an amorphous refractory material, characterized in that the heat-resistant fine powder is one or more selected from zircon powder and fused silica glass powder. The present invention also provides the method for producing an amorphous refractory material, wherein the inorganic fiber is E glass fiber, alkali resistant glass fiber or carbon fiber. The present invention also provides the method for producing an amorphous refractory material, wherein the inorganic binder is colloidal silica, alumina sol or titania sol.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be further described below.
The first step in the present invention is necessary for a composition for producing an amorphous refractory material, which comprises an inorganic binder as a solid content of 5 to 10% by mass, heat resistant fine powder 77 to 93% by mass, and inorganic fibers of 3 to 13% by mass. Is a step of preparing a slurry by adding and mixing water according to the above.

Examples of the inorganic binder include colloidal silica, alumina sol, titania sol and zirconia sol. Among them, colloidal silica, alumina sol and titania sol are preferable.

The heat resistant fine powder is not particularly limited, but for example, zircon powder, fused silica glass powder and the like are preferable. Zircon powder is excellent in low expansion and corrosion resistance among natural raw materials. Further, the fused silica glass powder is excellent in low expansion property at high temperature. The particle size of the heat-resistant fine powder is preferably 10 to 20 μm.

Examples of the inorganic fiber include glass fiber, silicon carbide fiber, alumina fiber, carbon fiber and the like. Among them, E glass fiber, alkali resistant glass fiber and carbon fiber are preferable. The inorganic fiber usually has a length of 3 to
It is possible to use one having a 9 mm and an aspect ratio of about 230 to 690. Further, according to the present invention, it is preferable to use the so-called hard type glass fiber in which the glass strands are sized especially among the inorganic fibers, and the monofilaments in the strands are bonded to each other. It is preferable that such glass fibers are used, for example, by converging 100 to 200 monofilaments having a diameter of 6 to 15 μm and a length of 3 to 9 mm. The glass fiber is known in the art, and commercially available one can be used, for example, manufactured by Nippon Electric Glass Co., Ltd. under the trade name ACS9PH-.
901X, manufactured by Cem-FIL International Limited, trade name Semfill 70 / 30-9 mm and the like. In the present invention, the hard type glass fiber may be used in combination with the soft type glass fiber shown below, but the amount thereof is 90% by mass in all the glass fibers used.
The above is preferable. Note that, unlike the hard type, it is also possible to use so-called soft type glass fibers in which monofilaments in the glass strand are not adhered to each other, but when a large amount of this soft type glass fiber is used, the glass fiber at the time of slurry preparation is prepared. May easily disintegrate into monofilaments and collect into monofilaments to form a dumpling, impairing the fluidity of the slurry. Therefore, when soft type glass fiber is used, it is preferably 1% by mass or less in the composition for producing an irregular shaped refractory.

The composition for producing an irregular shaped refractory used in the present invention contains an inorganic binder in a solid content of 5 to 10% by mass, preferably 6 to 9% by mass, and a heat resistant fine powder 77 to 93.
Wt%, preferably 80-90 wt%, and inorganic fibers 3-13 wt%, preferably 4-10 wt%.
The amorphous refractory composition is composed of only the above-mentioned three components. That is, the total of the three components in the composition is 100% by mass. If the use ratio of the inorganic binder is less than 5% by mass, the strength of the product is reduced,
On the contrary, if it exceeds 10% by mass, the dry crack resistance is deteriorated, which is not preferable. If the proportion of the heat-resistant fine powder used is less than 77% by mass, the impact resistance is lowered, and conversely, if it exceeds 93% by mass, the fluidity of the slurry is lowered, which is not preferable. If the proportion of the inorganic fibers used is less than 3% by mass, the desired thermal shock resistance and dry crack resistance cannot be obtained, and conversely 13
If it exceeds the mass%, the fluidity of the slurry is lowered, which is not preferable.

Next, if necessary, water is added to the composition for producing an irregular shaped refractory and mixed to prepare a slurry. For the slurry, for example, an inorganic binder and a heat resistant fine powder are mixed and stirred using a mixer for mixing cement mixture, for example, for about 30 seconds, and then inorganic fibers and, if necessary, water are added, and the three components are mixed. Can be prepared by mixing, for example, for about 30 to 60 seconds until the are uniformly mixed. Water is preferably added so that the total amount of water in the inorganic binder and the added water is 13 to 18% by mass. Further, the flow value of the slurry is 285 to 29.
It is preferably 5 mm (according to JIS R5201). Usually, an inorganic binder such as colloidal silica contains about 10 to 40% by mass of water, so that water may not necessarily be added at the time of preparing a slurry depending on the solid content concentration and the usage ratio of the inorganic binder.

The second step in the present invention is a step of pouring the slurry into a mold having a desired shape, drying and curing, and removing the mold. The formwork used in the present invention is not particularly limited, and for example, a plastic or iron formwork of any shape can be used (when an iron formwork is used, it is necessary to oil the formwork). ). Moreover, after pouring the slurry into a mold having a desired shape, it is desirable to remove bubbles in the slurry by using a vibrator. The drying temperature is, for example, 105 to 120 ° C., and the drying time is, for example, 12 to 24 hours. A cured product is obtained by performing such a drying step, and the cured product can be easily released from the mold. The cured product after demolding is
For example, by drying at 105 ° C. to 120 ° C., it is preferable to evaporate the residual moisture and bring it to an absolutely dry state.

[0013]

In the prior art disclosed in the above-mentioned JP-A-57-206548, a small amount of inorganic fiber (glass fiber or carbon fiber) of about 0.1 to 1% is used with respect to the heat resistant fine powder. . On the other hand, in the present invention, the desired thermal shock resistance and dry crack resistance are obtained by using a larger amount of inorganic fibers than that of the conventional technique (5 to 13 mass% when converted to the amount of heat resistant fine powder). I was able to. In the present invention, the role of the inorganic fibers is to increase the strength in the normal state and to absorb the stress of thermal strain during heating. For example, when the amorphous refractory produced by the present invention is used as a sprue in continuous aluminum casting, its shape becomes complicated like a cylindrical shape, and the thickness becomes thin, but the proportion of inorganic fibers used is small. Cracks occur during drying and curing, and it is difficult to make a product. An attempt was made to experimentally manufacture an amorphous refractory without using any inorganic fiber, but it was impossible to even maintain the shape due to cracking during drying and curing. According to the present invention, by setting the use ratio of the inorganic binder, the heat resistant fine powder and the inorganic fiber within a specific range, the casting becomes easy and the productivity is increased, and the desired thermal shock resistance and dry crack resistance are also provided. It was possible to obtain an amorphous refractory having

[0014]

EXAMPLES The present invention will be further described below with reference to Examples and Comparative Examples. Raw material inorganic binder used: Colloidal silica (manufactured by Nippon Kagaku Co., Ltd., trade name Silicadol-30S, SiO ₂ content 30 to 31% by mass, particle diameter 7 to 10 nm).

Heat-resistant fine powder: Zircon powder (produced in Australia) having an average particle size of 15 μm. Table 1 shows the compositional analysis values of the zircon powder.

[0016]

[Table 1]

Inorganic fiber: (1) E glass fiber (made by Nippon Electric Glass Co., trade name 03
1-33G, soft type, strand length 3 mm, monofilament diameter 13 μm) (2) E glass fiber (Nippon Electric Glass Co., Ltd., trade name EC
S03T-187, hard type, strand length 3m
m, 200 monofilaments having a diameter of 13 μm are converged); (3) Alkali resistant glass fiber (strand length 6 mm,
The following (5) glass fiber cut into 6 mm). (4) Alkali resistant glass fiber (Nippon Electric Glass Co., Ltd., trade name ACS9PH-901X, hard type, strand length 9 mm, diameter 13 μm monofilament 20
(5) Alkali resistant glass fiber (ARG) (manufactured by Nippon Electric Glass Co., Ltd., trade name ACS19PH-901X20V, hard type, strand length 19 mm, 200 monofilaments having a diameter of 13 μm are converged);

Examples 1 to 6 and Comparative Examples 1 to 6 The raw materials used were blended according to the blending ratios shown in Tables 2 and 3 to prepare slurries. The solid content of the slurry is 80 to 87% by mass, and the flow value of the slurry is 290 m.
It was m. The total amount of raw materials used was 700 g.
The slurry was prepared by first adding colloidal silica and zircon to Kenmix (cement mixture mixing mixer) and stirring for 30 seconds, then adding glass fibers and mixing and stirring for 30 seconds. The prepared slurry was cast using the following mold. Form: Outer diameter 120 mmφ x height 50 mm x thickness 1 mm plastic first cylindrical member, outer diameter 140 mmφ
A second cylindrical member made of plastic having a height of 50 mm and a thickness of 2 mm is prepared, and the second cylindrical member is placed inside the first cylinder.
A cylindrical member was arranged, and the bottom of which was sealed with aluminum tape so that a gap of about 10 mm was formed between them was used as a mold. Pour the slurry into this formwork for 10
It was demolded after being dried at 5 ° C. for 24 hours. 1 more after demolding
It was absolutely dried at 05 ° C. for 5 hours and used as a test sample.

The test samples were evaluated as follows. Pourability: After all components were mixed with Kenmix, the container was tilted, and the one in which the slurry flowed out smoothly was marked with ◯, the one that flowed out but the surface had irregularities was marked with Δ, and the one that did not flow out was marked with x. Drying crack resistance: The presence or absence of cracks in the test sample after being absolutely dried at 105 ° C. for 5 hours was observed. The case where no cracks were generated was evaluated as ◯, the case where 1 or 2 minute cracks were generated was evaluated as Δ, and the case where large cracks were generated was evaluated as x. Thermal shock resistance: The test sample was subjected to a crack test by heating the central part. That is, a 100 mmφ columnar lightweight brick with a nichrome wire wound around the outer periphery is used as a heater, and a test sample is placed outside the heater, and a calcium silicate plate is further placed outside the test sample for heat insulation. , Heater temperature from room temperature to 700
This is a test for observing the presence or absence of cracks when the temperature is raised to 20 ° C. in 20 minutes, 700 ° C. is held for 3 hours, and then cooled to 300 ° C. This test method is also adopted as the test method for the calcium silicate-based spruce alloy, which is currently widely used for aluminum refining. The case where no crack was generated was evaluated as ◯, the case where the crack did not reach the back surface even when the crack was generated was evaluated as Δ, and the crack which penetrated to the back surface was evaluated as x.

The test samples used for the following characteristic evaluation were prepared as follows. The slurry prepared as described above was poured into a mold frame of 40 mm × 40 mm × 160 mm, dried at 105 ° C. for 24 hours, and then demolded.
It was dried at ℃ for 5 hours and used as a test sample. Bulk specific gravity: The mass was measured with an electronic balance to one decimal place, and the thickness, width and length were measured with a caliper to calculate the bulk specific gravity. Bending strength (normal state): Measured according to JIS R5201. Bending strength (after heating): The bending strength after heating the test sample at 700 ° C. for 3 hours was measured according to JIS R5201. Heat shrinkage ratio: Measured according to JIS A9510 for an absolutely dry sample before heating and a sample after heating at 700 ° C. for 3 hours. Brinell hardness (normal state): Measured according to JIS Z2243. Brinell hardness (after heating): The Brinell hardness after heating the test sample at 700 ° C. for 3 hours was measured according to JIS Z2243. Al erodibility: Using the slurry prepared as described above, a commercially available stainless steel container is used as the outer frame, and the inner diameter is 140 m.
A crucible-shaped container having a thickness of m and a thickness of about 10 mm is prepared and dried in the same manner as the test sample to obtain a test body. Approximately 200 g of aluminum metal pieces were put there, and the whole crucible-shaped container was 700
It was placed in an electric furnace at 0 ° C., aluminum was melted and kept for 24 hours to be brought into contact with an aluminum solution. After cooling, the solidified aluminum was taken out, and the presence or absence of erosion of the contact portion of the test body with the aluminum solution was observed. The results are also shown in Tables 2 and 3.

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

Industrial Applicability According to the present invention, there is provided a method for producing an amorphous refractory which is excellent in thermal shock resistance, dry crack resistance and productivity and can be suitably used as a material which is in direct contact with molten metal.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsuyoshi Morohoshi             6-1 Kashiwara, Ishioka City, Ibaraki Prefecture Co., Ltd.             Building Materials Technology Laboratory F-term (reference) 4G033 AA06 AA07 AB05 AB06 AB12                 4K051 GA01 LC01 LG03

Claims (4)

[Claims] 1. An inorganic binder having a solid content of 5 to 10
Mass%, heat-resistant fine powder 77 to 93 mass% and inorganic fiber 3 to 13 mass% to a composition for producing an amorphous refractory material,
Irregular refractory material having a first step of adding and mixing water as needed to prepare a slurry, and a second step of pouring the slurry into a mold having a desired shape, drying and curing, and demolding Production method. 2. The method for producing an amorphous refractory material according to claim 1, wherein the heat-resistant fine powder is at least one selected from zircon powder and fused silica glass powder. 3. The method for producing an amorphous refractory material according to claim 1, wherein the inorganic fiber is E glass fiber, alkali resistant glass fiber or carbon fiber. 4. The method for producing an amorphous refractory material according to claim 1, wherein the inorganic binder is colloidal silica, alumina sol or titania sol.