JP2003292385A - Silicon carbide raw material for castable refractory having excellent drying property and corrosion resistance and raw material for the monolithic refractory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a silicon carbide raw material for efficiently manufacturing a castable refractory containing silicon carbide, which is very fine and excellent in corrosion resistance, and to obtain the raw material for the monolithic refractory. <P>SOLUTION: The silicon carbide raw material for the monolithic refractory giving superior drying property and corrosion resistance is characterized in that its average particle size is 0.05-3 mm, that the content of free silicon is 0.1-1 mass%, and that the proportion of the silicon carbide raw material having a particle size of ≤0.25 mm to that having a particle size of ≤0.045 mm is ≤20 mass%. The raw material for the monolithic refractory is obtained by adding 0.5-10 mass% (as an external percentage) of an alumina cement as a binder to 100 mass% of a refractory aggregate comprising 5-80 mass% of the above silicon carbide raw material and the balance of alumina and/or spinel. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a silicon carbide raw material suitable for a raw material of a silicon carbide-containing amorphous refractory used for a molten metal container, a molten metal processing apparatus, an incinerator, and the like, and a silicon carbide raw material thereof. Regarding the amorphous refractory raw material used.

[0002]

2. Description of the Related Art In most cases, silicon carbide raw materials that are industrially used are silica stones and silica sands (silicon oxides), which are obtained by electrically heating the raw materials silica stones and silica sands and carbon materials in an Acheson type electric furnace. It is produced by a so-called Acheson method in which silicon carbide is synthesized by reduction with carbon. It is possible to produce a relatively large silicon carbide ingot by the Acheson method, and it is crushed and classified according to the purpose and used as a silicon carbide raw material. Impurities in the obtained silicon carbide raw material are reaction products of the raw material silica stone / silica sand and carbon material, unreacted residual free silicon, free silicic acid, free carbon, or the raw material silica stone / silica sand. The main components are iron and aluminum, which are caused by impurities in the carbonaceous material and contamination from the grinding medium.

Silicon carbide is chemically stable with respect to molten glass, has relatively high oxidation resistance, has a small coefficient of thermal expansion as compared with oxides, and has high hardness. It is mainly used as a raw material for heat-resistant materials and amorphous refractories, heating elements, and abrasives. In addition, as a raw material for fine ceramics and a raw material for a coating utilizing the conductivity of silicon carbide, ultrafine silicon carbide powder having a particle size of 1 μm or less is used. Incidentally, the SiC raw material for paint is disclosed in JP-A-6-18.
As disclosed in Japanese Patent No. 3717, acid cleaning or alkali cleaning may be carried out for the purpose of removing a substance that reacts with water glass in the paint.

Amorphous refractory materials using silicon carbide include alumina-silicon carbide, alumina-spinel-silicon carbide, alumina-silicon carbide-carbonaceous, alumina-spinel-silicon carbide-carbonaceous materials. There are materials, etc., and in the steel manufacturing industry, they are mainly used in the ironmaking process such as blast furnaces, hot metal trucks and hot metal ladles. For example, for blast furnace tapping, an alumina-silicon carbide-carbonaceous amorphous refractory is generally used, and as a raw material other than alumina, silicon carbide, and carbon, mainly a cement such as alumina cement is used. Materials, carbon anti-oxidants such as boron carbide and borosilicate glass, aluminum, dry explosion-proof materials such as aluminum, organic foaming agents and organic fibers, etc. are added.

As a method for molding these irregular refractory materials, there are a pouring method, a spraying method and the like. In the pouring method,
After kneading the raw material and water with a mixer, the mixture is cast into a predetermined shape, molded, and cured to give a shape. In addition, the spraying method includes a dry method, a semi-dry method, and a wet method.For example, in the dry method, the above material is pressure-fed by compressed air, mixed with water immediately before the outlet of the hose, and sprayed on a work piece. And shape it. In the spraying method, it is necessary to rapidly cure the sprayed amorphous material, and therefore, in addition to the above raw materials, a quick-setting agent such as slaked lime, sodium aluminate, and water glass is used.

The shaped amorphous refractory material is used after being dried by heating to remove the kneading water. Among the above-mentioned raw materials, the dry explosion-proof material is formed by forming a ventilation path as an escape route for water vapor in advance so that a large water vapor pressure does not occur inside the amorphous refractory even if it is rapidly heated during drying. It is added for the purpose of preventing the explosion and crack generation of. As shown in the formula (1), aluminum reacts with kneading water which has been made alkaline by alumina cement or the like during curing to generate hydrogen gas, and forms a ventilation path when the hydrogen gas escapes from the amorphous refractory.

2Al + 2OH ⁻ + 6H ₂ O → 2Al (OH) ₄ ⁻ + 3H ₂ (1) Similarly, the organic foaming agent generates gas during curing, and when the gas escapes from the amorphous refractory, the gas is discharged through the ventilation path. Form. The organic fiber forms an aeration path by being dissolved in hot water during heating and drying or by dehydration shrinkage.

[0008] As described above, the dry explosion-proof material prevents the formation of explosions or cracks during the drying of the amorphous refractory by forming a ventilation path in advance for the steam to escape to the outside of the irregular refractory during the drying. Therefore, it is an excellent additive material from the viewpoint of construction of irregular refractory materials, but has a drawback from the viewpoint of material properties. Since this is a method for preventing explosion and cracking during drying by forming a ventilation path, the pore diameter of the obtained amorphous refractory becomes large, which is not preferable from the viewpoint of oxidation resistance and slag infiltration resistance. In addition, aluminum and organic foaming agents may form fine cracks in the material due to the gas generated during curing when the amorphous refractory is insufficiently cured, and in extreme cases, the material may swell greatly. . The organic fiber increases the kneading water content, and since the portion where the organic fiber is burnt off becomes pores, the pore diameter and porosity of the obtained amorphous refractory material increase. That is, the addition of the dry explosion-proof material is not preferable from the viewpoint of material properties, because it forms defects in the amorphous refractory and increases the porosity.

The invention disclosed in Japanese Unexamined Patent Publication No. 6-183717, in which the SiC powder is treated with alkali, has an average particle size of 1
Ultra-fine powder of less than μm with Si content of 0.02% by mass or less, and a raw material for conductive paint for interior of color cathode ray tube for very high-purity SiC with the purpose of preventing hydrogen gas generation The average particle size and purity are different from those of the SiC for amorphous refractory targeted by the present invention, and the explosion and defects of the amorphous refractory during curing / drying are prevented,
About manufacturing irregular shaped refractory with excellent corrosion resistance,
Nothing is listed.

The amorphous refractory densified without using the explosion-proofing agent can avoid explosion due to water vapor pressure if it is dried over time, but the production efficiency becomes very poor. In this case, as disclosed by the applicant in Japanese Patent Publication No. 54-32175 and Japanese Patent Application No. 2001-117335,
By using microwave drying in which an amorphous refractory material is irradiated with microwaves to heat the interior, efficient drying is possible.

However, the amorphous refractory material containing silicon carbide has a small amount of the explosion-proof agent added, and
If it is densified, even if it is microwave-dried, a crack may occur or an explosion may occur at 60 ° C or higher during drying. this is,
Hydrogen generated when free silicon contained as an impurity in the silicon carbide raw material as shown in the following formula (2) reacts with the alumina cement in the amorphous refractory raw material or the kneading water made alkaline by the basic raw material. The cause is the pressure of the gas.

Si + 2OH ⁻ + H ₂ O → SiO ₃ ^{2 −} + 2H ₂ (2) Microwave heating enables highly accurate temperature control, and since it is internal heating, the temperature distribution of the material varies during drying. Can be very small. Therefore, by uniformly controlling the temperature of the entire material, it is possible to control the water vapor pressure generated inside and prevent the occurrence of cracks and explosions due to the water vapor pressure. However, the generation of hydrogen gas according to the equation (2) is a chemical reaction, and it is difficult to control it depending on the temperature. In the microwave drying, the entire material is heated uniformly, and hydrogen gas is generated all at once in the entire material according to the equation (2), so that dry cracks and explosions are more likely to occur than in ordinary hot air drying.

Report on the 61st Committee of Raw Material Special Committee (Association of Refractory Technology, September 13, 2001) Page 22 "Problem of adding silicon carbide to dense castable block" It has been described that it is effective to prevent Si (free silicon) from exploding by reacting a silicon carbide raw material containing a small amount of free silicon) with an alkaline aqueous solution in advance, but it is effective for other than alkaline cleaning. Nothing is described about a method for preventing explosion by means or a method for producing an amorphous refractory having excellent corrosion resistance.

[0014]

DISCLOSURE OF THE INVENTION The present invention prevents explosion and defects of amorphous refractory during curing and drying without performing pretreatment for reacting a silicon carbide raw material with an aqueous alkali solution, and improves the drying property. And a silicon carbide raw material and an amorphous refractory raw material for producing an amorphous refractory having excellent corrosion resistance.

[0015]

The gist of the present invention is as described in (1) to (8) below.

(1) A raw material of silicon carbide having an average particle size of 0.05 mm to 3 mm and a free silicon content of 0.1 to 1% by mass.
And the ratio of the silicon carbide raw material having a particle diameter of 0.045 mm or less to the silicon carbide raw material having a particle diameter of 0.25 mm or less is 20% by mass.
A silicon carbide raw material for amorphous refractory having excellent dryness and corrosion resistance, which is characterized in that:

(2) The amount of gas generated per unit mass of the silicon carbide raw material when heated in an alkaline aqueous solution at 80 ° C. for 24 hours is 0.0055 Nm ³ / kg or less, (1) A silicon carbide raw material for amorphous refractory which has excellent dryness and corrosion resistance as described.

(3) Maximum particle size of amorphous refractory raw material 10 mm
The following part is composed of 5 to 80% by mass of the silicon carbide raw material described in (1) or (2) above and the balance of 100% by mass of a refractory aggregate made of an alumina raw material and / or a spinel raw material, and as a binder. Amorphous refractory raw material with excellent dryness and corrosion resistance, characterized by adding 0.5-10% by mass of alumina cement.

(4) Furthermore, 0.5 to 10% by mass of the carbon raw material is added internally to 100% by mass of the refractory aggregate having a maximum particle size of 10 mm or less.
An amorphous refractory raw material excellent in dryness and corrosion resistance according to the above (3), characterized by containing.

(5) Further, with respect to 100% by mass of the refractory aggregate having a maximum particle size of 10 mm or less, an alumina raw material having a particle size of 10 to 100 mm,
Spinel raw material, silicon carbide raw material, alumina and / or spinel-silicon carbide, alumina and / or spinel-
Silicon Carbide-External application of one or more carbonaceous materials
The amorphous refractory raw material having excellent dryness and corrosion resistance according to the above (3) or (4), characterized by containing 5 to 100% by mass.

(6) Refractory aggregate 100 with a maximum particle size of 10 mm or less
0.01% to 1% by mass of aluminum, organic foaming agent, organic fiber, or one or more of them in total, relative to% by mass.
Any one of the above (3) to (5) characterized by containing 1
The amorphous refractory raw material excellent in dryness and corrosion resistance according to the item.

(7) After mixing the amorphous refractory raw material with water, 80
Drying according to any one of (3) to (6) above, wherein the amount of gas generated per unit mass of the amorphous refractory is 0.001 Nm ³ / kg or less when heated at 24 ° C for 24 hours. A non-standard refractory raw material with excellent corrosion resistance and corrosion resistance.

(8) The amorphous refractory raw material excellent in drying property and corrosion resistance according to any one of (3) to (7), which is used for microwave drying.

In the present invention, the ratio of the particle size of 0.25 mm or less is the ratio of passing through the JIS sieve of 0.250 mm in a wet process, and the ratio of the particle size of 0.045 mm or less is 0.045 mm.
It is the rate of passing through the sieve in a wet manner. In addition, the average particle size was calculated from those values by measuring the particle size larger than 0.125 mm with a JIS sieve and the particle size of 0.125 mm or less with a laser diffraction / scattering particle size distribution measuring device manufactured by Horiba. It was defined as the particle size.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION As one means for improving the corrosion resistance of an amorphous refractory, the present inventors have achieved densification of an irregular refractory and removal of an explosion-proof material at the same time, and have explosive blasting by steam pressure. Microwave drying was studied in order to dry efficiently without performing. As a result, microwave drying
Although it is a very efficient method of drying water, when it is used to dry amorphous refractory containing silicon carbide raw material, it is dried by hydrogen gas generated due to free silicon in the silicon carbide raw material. It was discovered that the occurrence of cracks and explosions was more pronounced than with conventional hot air drying.

The present inventors pay attention to the particle size of the silicon carbide raw material in order to prevent the generation of this hydrogen gas, and the hydrogen gas is mainly generated from the silicon carbide raw material having a particle size of 0.045 mm or less. I found that. It was discovered that by defining the particle size and free silicon content of the silicon carbide raw material, it is possible to prevent the dry cracks and explosions peculiar to silicon carbide-containing amorphous refractories.

The present invention will be described in detail below.

In the invention according to (1) above, the silicon carbide raw material used for the amorphous refractory has an average particle size of 0.05 mm.
~ 3 mm, the free silicon content is 0.1 to 1% by mass, and the ratio of the silicon carbide raw material having a particle size of 0.045 mm or less to the silicon carbide raw material having a particle size of 0.25 mm or less is 20% by mass or less. To do. For example, when using a silicon carbide raw material with a particle size of 1 mm or less for an amorphous refractory raw material, the silicon carbide raw material with a particle size of 0.045 mm or less for the silicon carbide raw material with a particle size of 0.25 mm or less is used. The ratio of the silicon carbide raw material is 20 mass% or less.

When a silicon carbide raw material having an average particle size of less than 0.05 mm is used as an amorphous refractory raw material, it tends to be in the ultrafine powder region, while a silicon carbide raw material having an average particle size of more than 3 mm is used. When is used as an amorphous refractory raw material, it tends to be in the coarse grain region. In this way, if the silicon carbide raw material is biased toward the ultrafine powder region or coarse grain region of the amorphous refractory raw material, not only the fluidity required when constructing the amorphous refractory cannot be obtained, but also the irregular refractory The effect of improving the chemical stability and imparting low thermal expansion to the molten slag, which is the purpose of adding the silicon carbide raw material to the product, cannot be obtained.

The free silicon content in the silicon carbide raw material is 1
If the content exceeds 100% by mass, the amount of hydrogen gas generated by the reaction of free silicon with the kneading water that has become alkaline due to alumina cement, etc. during drying increases, and dense amorphous refractory may crack or explode. There is a case. Further, in the case of application to an irregular shaped refractory, it is not necessary to set the average free silicon content in silicon carbide to less than 0.1 mass% from the viewpoint of effect and cost. Therefore, the content of free silicon in the raw material of silicon carbide is 0.1 to 1% by mass. Here, the free silicon content in the silicon carbide raw material is defined as the free silicon content measured according to the method for chemical analysis of JIS-R6124 silicon carbide abrasives.

When the ratio of the silicon carbide raw material having a particle diameter of 0.045 mm or less to the silicon carbide raw material having a particle diameter of 0.25 mm or more exceeds 20% by mass, the kneading water and the carbonized water which become alkali by the alumina cement are dried during drying. Hydrogen gas generated by the reaction of free silicon in the silicon raw material increases, and the dense amorphous refractory may crack or explode, which is considered to be due to the following reasons.

In the Acheson method, silica stone / silica sand (SiO ₂ ) is reduced by carbon (C) to produce a silicon carbide ingot. At that time, in the silicon carbide crystal of the silicon carbide ingot and at grain boundaries. Fine free silicon is generated. Since the silicon carbide raw material, which is the raw material for amorphous refractory, is obtained by crushing the silicon carbide ingot, free silicon in the silicon carbide raw material exists inside and on the surface of the particles of the silicon carbide raw material. In some cases, it may exist as fine particles of free silicon alone in the crushing process. As a result of the pulverization, free silicon existing as particles in a single phase is present in the fine powder part of the silicon carbide raw material, and silicon carbide particles with a small particle size in the fine powder part have free silicon appearing on the surface of the silicon carbide particles. The probability of being is increasing. Therefore, most of the free silicon present in the fine powder part of the silicon carbide raw material is not surrounded by silicon carbide, so the alumina cement in the amorphous refractory raw material or the kneading water made alkaline by the raw material. Contact with
When the temperature rises above 60 ° C during the drying process of amorphous refractory, hydrogen gas is actively generated according to the formula (2), which causes dry cracks and explosions of dense irregular refractory. In other words, when the proportion of fine silicon carbide raw material increases, the amount of hydrogen gas generated by the reaction of the kneading water made alkaline by alumina cement and the free silicon in the silicon carbide raw material increases during the drying, resulting in a dense Atypical refractory may crack or explode.

The smaller the ratio of the silicon carbide raw material having a particle diameter of 0.045 mm or less to the silicon carbide raw material having a particle diameter of 0.25 mm or less, the more preferable lower limit is not specified. However, from the viewpoint of manufacturing problems and cost, 1% by mass. You don't have to:

In the invention according to (2) above, the silicon carbide raw material used for the amorphous refractory is 100 g of the silicon carbide raw material, 200 g of the 5 wt% sodium hydroxide aqueous solution at 80 ° C.
The amount of gas generated per unit mass of the silicon carbide raw material when heated for 24 hours at 0.0055 Nm ³ / kg or less. The amount of gas generated per unit mass of silicon carbide raw material is 0.00
If it exceeds 55 Nm ³ / kg, a very dense amorphous refractory may crack or explode during drying. Particularly preferably, the amount of gas generated per unit mass of silicon carbide is 0.003 Nm ³ / kg or less, more preferably 0.003 Nm ³ / kg or less.
It is preferably 2 Nm ³ / kg or less. In particular, when using microwaves for drying, it is preferably 0.002 Nm ³ / kg or less.

In the invention according to (3), the portion of the amorphous refractory raw material having a maximum particle size of 10 mm or less is 5 to 80 mass% of the silicon carbide raw material as described in (1) or (2) above, and the balance is Refractory aggregate made of alumina raw material and / or spinel raw material 10
In the invention according to (4) above, 100% by mass of refractory aggregate containing 0.5 to 10% by mass of carbon raw material is further added to the outside of alumina cement as a binder.
Add 5-10% by mass. Maximum particle size of amorphous refractory raw material 10
Since the portion exceeding mm is not particularly limited, not only the material containing a raw material having a particle size of more than 10 mm but also the material not containing it is within the scope of the invention according to (3) or (4).

The amorphous refractory raw material thus prepared can produce a very dense amorphous refractory, and has excellent corrosion resistance, spalling resistance, and dryness, and alumina and / or spinel. -Silicon carbide amorphous refractory,
Alternatively, alumina and / or spinel-silicon carbide-carbonaceous amorphous refractory can be obtained.

Here, as the silicon carbide raw material, the silicon carbide raw material satisfying the above conditions is used as the refractory aggregate 10 having a maximum particle size of 10 mm or less.
Use 5 to 80% by mass for 0% by mass. If the amount used is less than 5% by mass, the corrosion resistance and spalling resistance to molten slag will decrease, and if it exceeds 80% by mass, the corrosion resistance to molten iron will decrease.

Alumina raw material is fused or sintered alumina,
One or more kinds of alumina-based refractory aggregates having an alumina content of 80% by mass or more such as calcined alumina, calcined bauxite, and shale shale are used.

The spinel raw material is electrofused or sintered spinel,
Use one or more of the spinel refractory aggregates such as calcined spinel. This spinel is a common type,
Any of the alumina rich type may be used. In addition, according to the thermite method, MgO—Al ₂ O ₃ -based vanadium slag represented by waste slag produced as a by-product in the production process of an iron-vanadium alloy can be used as a spinel.

The total amount of the alumina raw material and / or the spinel raw material used is preferably 10 to 80% by mass as an internal multiplication with respect to 100% by mass of the refractory aggregate having a maximum particle size of 10 mm or less. If the amount used is less than 10% by mass, the corrosion resistance to molten iron will decrease, and if it exceeds 80% by mass, the corrosion resistance and spalling resistance to molten slag will decrease.

The carbon raw material is one or more selected from pitch, mesophase pitch, carbon black, artificial graphite, scaly graphite, earthy graphite, coke, anthracite, and the like.
0.5 to 10% by mass is used for 100% by mass of refractory aggregate. To obtain a dense amorphous refractory, it is preferable to use pitch, mesophase pitch or carbon black. The carbon raw material may be used for the purpose of preventing slag infiltration by utilizing the property that it is difficult to wet the molten slag, but such an effect cannot be obtained if the amount used is less than 0.5% by mass. On the other hand, if the amount used exceeds 10% by mass, the amount of water for kneading becomes large and a dense amorphous refractory cannot be obtained.

Other refractory aggregates include electromelted or synthetic mullite, sillimanite, andalusite, kyanite, chamotte, clay, loastone, silica stone, fused silica,
Silica fine particles such as evaporative silica, fused or sintered magnesia, fused or sintered zirconia, zircon, chrome ore, fused or sintered magnesia-lime, fused zirconia-mullite, fused alumina-zirconia, silicon nitride , Refractory raw materials such as iron silicon nitride and titania, and alumina and / or spinel-silicon carbide, alumina and / or spinel-
A material such as silicon carbide-carbonaceous material can be used within a range of 30 mass% within 100 mass% of a refractory aggregate having a particle diameter of 10 mm or less.

In the present invention, 100% by mass of the refractory aggregate means the total amount of the alumina raw material, the spinel raw material, the carbon raw material and the other refractory aggregates having a particle diameter of 10 mm or less.
The value is 100% by mass. These refractory aggregates are used after being adjusted to have a particle size composition suitable as an irregular refractory material. Further, alumina and / or spinel-silicon carbide, which can be used as other refractory aggregates, materials such as alumina and / or spinel-silicon carbide-carbonaceous material, are not used in an actual furnace of the above material, or It is possible to use the standard brick after using the actual furnace or the irregular refractory material with the particle size adjusted to 10 mm or less. Of course, the refractory raw material may be molded into a particle size of 10 mm or less so as to be the above material.

Alumina cement is, for example, 1 out of those classified into JIS standard 1, 2, or 3 etc.
0.5% to 10% by mass of one kind or two or more kinds is applied to 100% by mass of the refractory aggregate by external coating. If the amount used is less than 0.5% by mass, the strength of the irregular shaped refractory becomes small, and if it exceeds 10% by mass, the corrosion resistance decreases. Although alumina cement is used as a binder, other binders such as phosphate, silicate, magnesia cement, aluminum lactate, aluminum glycolate, and lactic acid-aluminum glycolate may be used in combination.

In addition, additives such as a dispersant, an antioxidant, a metal fiber, a dry explosion-proof material and the like, which are generally added to the amorphous refractory raw material, can be used if necessary.

Examples of the additives include condensed polyphosphoric acids such as tripolyphosphoric acid, hexametaphosphoric acid, ultrapolyphosphoric acid, acidic hexametaphosphoric acid and polymetaphosphoric acid, inorganic acids such as boric acid and carbonic acid, and salts thereof, citric acid, and the like, as dispersants. One or more of organic acids such as tartaric acid, polyacrylic acid, polymethacrylic acid, polycarboxylic acid, sulfonic acid, lignin sulfonic acid, melamine sulfonic acid, polystyrene sulfonic acid, naphthalene sulfonic acid and salts thereof and the like. It is possible to add approximately 0.01 to 1% by mass to the refractory aggregate 100% by mass. As other additives,
A hardening accelerator, a hardening retarder, a thickening agent, etc. can be added to about 0.01 to 1% by mass with respect to 100% by mass of the refractory aggregate.

The antioxidant is a refractory aggregate made of boron carbide, silicon nitride, zirconium boride, calcium boride, phosphate glass, borosilicate glass, borophosphate glass, etc. for the purpose of preventing oxidation of carbon during heating. It is possible to use about 0.01 to 5% by mass with respect to 100% by mass. Also, as an antioxidant, a metal such as aluminum, silicon, or an aluminum-silicon alloy is used as a refractory aggregate 100% by mass.
It is possible to add about 0.01 to 10% by mass to the outside, but in that case, it is necessary to take measures such as coating the metal surface so that the metal does not react with water during kneading, curing and drying. is there.

For the purpose of reducing the occurrence of cracks during the use of amorphous refractory, the metal fiber is made of steel, stainless steel, or the like, and is 0.1 to 10 when the fiber is 100% by mass of the refractory aggregate.
It can be added in an amount of about mass%. The shape is 10-50m long
It is preferable to have a linear shape with m and a sectional length of 0.1 to 1 mm.

As in the invention (6) described later, any one or more of aluminum powder, organic foaming agents, organic fibers and the like can be added as the dry explosion-proof material in the present invention. Addition of these increases the pore size and porosity, so it is preferable not to add them.

Furthermore, in the invention according to (5) above, 10
100 to 100% by mass of refractory aggregate with a particle size of 10 to 100 mm
Alumina raw material, spinel raw material, silicon carbide raw material, alumina and / or spinel-silicon carbide, alumina and / or spinel-silicon carbide-carbonaceous material, or 2
It is possible to add 5 to 100% by mass of one or more seeds to be used. As the alumina raw material and the spinel raw material, the same materials as the alumina raw material and the spinel raw material for the refractory aggregate can be used. As the silicon carbide raw material, one produced by a usual Acheson method is used. The free silicon content in the silicon carbide raw material, the total content of free silicon and free silicic acid and the free carbon content are within the range of silicon carbide which is usually industrially produced by the Acheson method. No problem, but 0.12
It is preferable to satisfy the same specified range as the portion of 5 mm or less.

Alumina and / or spinel-silicon carbide and alumina and / or spinel-silicon carbide-carbonaceous materials are the above-mentioned alumina raw materials, spinel raw materials, silicon carbide raw materials and carbon raw materials for refractory aggregates. It is a main raw material, and can contain a binder, the above-mentioned other refractory aggregates, and the like within a range of 30 mass% or less.

Alumina and / or spinel-silicon carbide and alumina and / or spinel-silicon carbide-carbonaceous materials are used in the above-mentioned materials in the actual furnace or in the form of bricks after use in the actual furnace, or The size of the standard refractory is 10 to 10
It can be adjusted to 0 mm before use. Further, the refractory raw material may be molded into a particle size of 10 to 100 mm so as to be the above material and used.

Furthermore, one or more raw materials having other compositions having a particle size of 10 to 100 mm, for example, one or more materials having the other composition such as the above-mentioned other refractory aggregates and magnesia-carbonaceous materials are used as refractory bones. If it is less than 20% by mass, it can be added to 100% by mass of the material.

In the invention according to (6) above, as the dry explosion-proof material, any one kind or two kinds or more of aluminum, an organic foaming agent, an organic fiber, etc. is used as a total of 100% by mass of the refractory aggregate.
0.01 to 1% by mass can be used. Examples of the organic foaming agent include azodicarbonamide, and
Organic fibers include polymer organic fibers such as vinylon (including polyvinyl alcohol), rayon, polyester, nylon, polypropylene, and polyethylene.

However, since aluminum, organic foaming agents, and organic fibers form defects in the amorphous refractory and increase the pore size and porosity as described above, when manufacturing a dense amorphous refractory, With respect to 100% by mass of refractory aggregate, aluminum is preferably 0.1% by mass or less, organic foaming agent is 0.1% by mass or less, and organic fiber is preferably 0.1% by mass or less.

In the invention according to (7) above, the
The amorphous refractory raw material is kneaded with water and then heated at 80 ° C for 24 hours.
The amount of gas generated per unit mass of amorphous refractory is 0.00
1 Nm ³/ Kg or less, preferably 0.0005 Nm^Three/ Kg or less
It will be. Gas generation amount is 0.001Nm³From / kg
Dense, amorphous refractories often crack during drying
May occur or explode.

As in the conventional case, the molding of the amorphous refractory is carried out by adding 3 to 10% by mass of kneading water to 100% by mass of the irregular refractory material of the present invention having a particle size of 10 mm or less. ,
It is carried out by a pouring method or a spraying method. In the case of cast molding, the kneading water is 3 to 7 mass%, preferably 3
Adjust to be ~ 5 mass% to obtain a dense amorphous refractory. In the spraying method, it is necessary to rapidly cure the sprayed amorphous material. Therefore, in addition to the above raw materials, a quick-setting agent such as slaked lime, sodium aluminate, and water glass is used.

In the invention according to (8) above, the amorphous refractory material of the present invention is used after curing, drying after molding, and is suitable for use in drying utilizing microwaves. According to equation (2), hydrogen gas generated due to free silicon in the silicon carbide raw material is 60 ° C during drying.
When the temperature becomes higher than the above value, the amount of generation will increase rapidly. Microwave drying is an efficient internal heating method,
Although it is a drying method that enables uniform heating, the temperature inside the amorphous refractory reaches 60 ° C or more evenly during the drying due to the uniform heating, and hydrogen gas is generated all at once inside the amorphous refractory. Will be done. Therefore, in the case of drying using microwaves, the increase in internal gas pressure caused by the hydrogen gas is larger than in the case of conventional drying by external heating, and cracks and explosions are more likely to occur during drying. Since the amorphous refractory raw material of the present invention is less likely to generate hydrogen gas due to free silicon in the silicon carbide raw material, it is possible to efficiently dry a dense amorphous refractory using microwaves. it can.

[0059]

EXAMPLES [Example 1] Table 1 shows silicon carbide raw materials of Examples of the present invention and Comparative Examples.

[0060]

[Table 1]

"Maximum particle size (mm)" of silicon carbide raw material
Is a value measured through a JIS sieve. "Average particle size (mm)" is the value obtained by measuring the particle size larger than 0.125 mm through a wet JIS sieve, and the particle size of 0.125 mm or less by the laser diffraction / scattering particle size distribution measuring device manufactured by Horiba. It is the median particle size calculated from. The “free silicon content (mass%)” is the free silicon content of the silicon carbide raw material measured according to the chemical analysis method for JIS-R6124 silicon carbide abrasives. "A: 0.25 mm
"The following ratio (mass%)" is based on JIS 0.250 mm
The ratio of particles that have passed through the No. Sieve, "B: 0.045 m
The ratio (mass%) of m or less "is 0.045 m according to JIS in wet type.
It is the proportion of particles that have passed through the m sieve. "B ÷ A × 10
“0” means the ratio (mass%) of the silicon carbide raw material having a particle diameter of 0.045 mm or less to the silicon carbide raw material having a particle diameter of 0.25 mm or less.
Is. Also, "gas generation amount" is V
Type cone mixer for 1 hour, then mix silicon carbide raw material and 10 mass% sodium hydroxide aqueous solution at a mass ratio of 1: 2, and gas per unit mass of silicon carbide raw material when heated at 80 ° C for 24 hours Indicates the amount generated.

Examples A to G are silicon carbide raw materials satisfying the conditions of the present invention, and a small amount of gas is generated when they are brought into contact with an alkaline aqueous solution.

Comparative Example H has a particle size of 0.045 according to the conditions of the present invention.
It is a silicon carbide raw material with a large proportion of mm or less, and a large amount of gas is generated when it comes into contact with an alkaline aqueous solution. [Example 2] Tables 2 and 3 show examples and comparative examples of the amorphous refractory raw material of the present invention.

[0064]

[Table 2]

[0065]

[Table 3]

The column of "gas generation amount" in the table shows the gas generation amount per unit mass of the amorphous refractory when the amorphous refractory after curing was heated in a wet state at 80 ° C for 24 hours. The amount of gas generated was determined by kneading the amorphous refractory raw materials in the proportions shown in the table with water, filling 2 kg of the Erlenmeyer flask and curing for 24 hours, and then adding 0.3 kg of water to the Erlenmeyer flask under the above conditions. When heated, the gas generated during heating was sampled by the water displacement method and weighed. The kneading and curing were carried out at 25 ° C.

In the column of "presence or absence of cracks after drying" in the table, after mixing the amorphous refractory raw material in the ratio shown in the table with water, 500
If there is a blast or crack when microwave-drying or hot-air drying is performed after cast molding into a shape of × 500 × 300 mm, curing for 24 hours, and then deframed, “Yes”; "Nothing" is entered. In the "Drying method" column, the microwave-dried amorphous refractory is "M
W ”, hot air dried amorphous refractories are described as“ hot air ”. For microwave drying, an amorphous refractory is installed in a stainless steel applicator (internal dimensions: 1000 x 1000 x 1000 mm), irradiated with 2.45 GHz microwave, and from the center of the irregular refractory 10 to 20 It was carried out by sending air having a temperature lower by ℃ to the inside of the applicator and discharging water vapor generated from the amorphous refractory to the outside of the applicator. The heating was performed by adjusting the microwave output so that the temperature at the central portion became the schedule shown in FIG. The hot-air drying was performed by adjusting the hot-air temperature sent to the dryer equipped with the irregular refractory material so that the schedule was as shown in FIG.

"Compressive strength", "Apparent porosity" in the table,
The "melting index" is 500 x 500 x 300 dried by the above method.
The value measured by cutting out a test piece from the central portion of the mm-shaped irregular-shaped refractory is shown. "Compressive strength" and "apparent porosity"
Was measured with a 40 × 40 × 40 mm test piece. "Melting index"
Is the amount of erosion measured at 1550 ° C by the high frequency lining method using blast furnace slag and pig iron as an erosion agent.
It is a value expressed as an index with the amount of erosion of 1 being 100, and the smaller the index, the smaller the amount of erosion and the higher the corrosion resistance.

Examples 1 to 15 are the amorphous refractory raw materials of the present invention, and even if a dense amorphous refractory was manufactured, no explosion or cracking occurred during drying.

Comparative Example 1 has a particle size of 0.045 according to the conditions of the present invention.
Since it is an amorphous refractory raw material that uses a silicon carbide raw material with a large proportion of silicon carbide raw materials of mm or less, the dense amorphous refractory is dried because the amount of gas generated during the drying of the amorphous refractory is large. Then a crack occurred. Comparative Example 2 is a case where the amount of silicon carbide raw material used is less than the definition of the present invention,
The amount of melting loss was large as compared with the examples. Comparative Example 3
In the case where the amount of alumina cement used was less than the regulation of the present invention, the strength was very low, and it was not possible to cut out a sample for measuring physical properties. In Comparative Example 4, the amount of alumina cement used was larger than the amount specified in the present invention, and the amount of erosion was large as compared with the Examples.

[0071]

INDUSTRIAL APPLICABILITY The silicon carbide raw material for amorphous refractory having excellent dryness and corrosion resistance of the present invention, the method for producing the same and the amorphous refractory raw material are capable of producing extremely dense amorphous refractory. Therefore, the industrial value thereof is extremely large as a refractory material that can cope with the severer operating conditions of the molten metal volume or the molten metal processing apparatus in recent years and the reduction of the basic unit of the refractory.

[Brief description of drawings]

FIG. 1 is a diagram showing a heating temperature schedule.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hatsuo Hira             20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel shares             Company Technology Development Division (72) Inventor Yoshitoshi Saito             20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel shares             Company Technology Development Division (72) Inventor Hitoshi Nakagawa             12 Nakamachi, Muroran City, Hokkaido Nippon Steel Corporation Stock             Muroran Works (72) Inventor Yasunori Tanaka             1-1 Higashihama-cho, Hachiman Nishi-ku, Kitakyushu City, Fukuoka Prefecture             Kurosaki Harima Co., Ltd. Technical Research Center (72) Inventor Kazuyuki Sugiyama             1-1 Higashihama-cho, Hachiman Nishi-ku, Kitakyushu City, Fukuoka Prefecture             Kurosaki Harima Co., Ltd. Technical Research Center (72) Inventor Toshihiro Isobe             1-1 Higashihama-cho, Hachiman Nishi-ku, Kitakyushu City, Fukuoka Prefecture             Kurosaki Harima Co., Ltd. 2nd Manufacturing Division Yahata Mugen             Shape factory (72) Inventor Hiroyoshi Tomino             1-1 Higashihama-cho, Hachiman Nishi-ku, Kitakyushu City, Fukuoka Prefecture             Kurosaki Harima Co., Ltd. 2nd Manufacturing Division Yahata Mugen             Shape factory F-term (reference) 4G033 AA02 AA09 AA15 AA17 AB02                       AB10 AB23 AB25 AB27 BA01                       BA02                 4K051 AA00 BE00

Claims (8)

[Claims] 1. A silicon carbide raw material having an average particle diameter of 0.05 mm to 3 mm, a free silicon content of 0.1 to 1 mass%, and a particle diameter for a silicon carbide raw material having a particle diameter of 0.25 mm or less.
A silicon carbide raw material for amorphous refractory having excellent dryness and corrosion resistance, characterized in that the proportion of the silicon carbide raw material having a diameter of 0.045 mm or less is 20% by mass or less. 2. The amount of gas generated per unit mass of the silicon carbide raw material when heated in an alkaline aqueous solution at 80 ° C. for 24 hours is 0.0055 Nm ³ / kg or less. Silicon carbide raw material for amorphous refractory with excellent dryness and corrosion resistance. 3. The portion of the amorphous refractory raw material having a maximum particle size of 10 mm or less is the silicon carbide raw material 5 to 80 according to claim 1 or 2.
Excellent dryness and corrosion resistance, characterized by adding 0.5 to 10% by mass of alumina cement as a binder to 100% by mass of the refractory aggregate consisting of the mass% and the balance made of alumina raw material and / or spinel raw material. Amorphous refractory raw material. 4. A refractory aggregate 10 having a maximum particle size of 10 mm or less.
4. The amorphous refractory raw material excellent in drying property and corrosion resistance according to claim 3, wherein the carbon raw material is contained in an amount of 0.5 to 10 mass% with respect to 0 mass%. 5. A refractory aggregate 10 having a maximum particle size of 10 mm or less.
One kind of alumina raw material, spinel raw material, silicon carbide raw material, alumina and / or spinel-silicon carbide, alumina and / or spinel-silicon carbide-carbonaceous material having a particle size of 10 to 100 mm relative to 0 mass% Or 5 to 1 with 2 or more
The amorphous refractory raw material excellent in dryness and corrosion resistance according to claim 3 or 4, characterized in that the content is 00% by mass. 6. A total of 0.01 to 1 mass% of aluminum, an organic foaming agent, or any one or more kinds of organic fibers is externally applied to 100 mass% of a refractory aggregate having a maximum particle size of 10 mm or less. An amorphous refractory raw material having excellent dryness and corrosion resistance according to any one of claims 3 to 5. 7. After kneading the amorphous refractory raw material with water, at 80 ° C.
Excellent dryness and corrosion resistance according to any one of claims 3 to 6, characterized in that the amount of gas generated per unit mass of amorphous refractory when heated for 24 hours is 0.001 Nm ³ / kg or less. Amorphous refractory raw material. 8. The amorphous refractory raw material excellent in drying property and corrosion resistance according to any one of claims 3 to 7, which is used for microwave drying.