JPH05279135A - Carbon-containing amorphous refractory - Google Patents

Abstract

PURPOSE:To provide the subject amorphous refractory having such high corrosion and thermal shock resistance as to be usable in refining vessels for molten steel. CONSTITUTION:The objective dense refractory can be obtained by incorporating (A) a blend of 50-70 pts.wt. of magnesia and/or alumina clinker, (B) 20-40 pts.wt. of carbon-contg. fused clinker, and (C) 3-10 pts.wt. of carbon powder with (B) such ingredients as binder, deflocculant and water followed by baking to develop binding between the carbon in the clinker and that out of the clinker. This refractory has durability enough to be usable as a lining refractory for refining vessels for molten steel owing to the above advantages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous refractory containing a carbon-containing raw material for an electromelting refractory, and more particularly to an lining refractory for refining molten steel.

[0002]

2. Description of the Related Art Carbon-containing unfired bricks are currently being used more and more due to their high slag infiltration resistance and thermal shock resistance, but carbon-containing unshaped refractories are used for blast furnaces. It is limited to casting materials around tapholes, hot metal gutters, etc., and stamp materials at the bottom of the blast furnace. This restriction on use is due to the fact that increasing the amount of added water due to the inclusion of carbon leads to an increase in porosity, and a dense construction body cannot be formed. Therefore, in order to improve this, it has been attempted to add a phosphate etc. as a deflocculating agent to reduce the added water content (for example, Japanese Patent Laid-Open No. 60-42281), but the porosity of the molded body is still. Is big.

[0003]

Since the amorphous material cannot be pressure-molded at the time of construction due to its characteristics, the porosity of the entire structure is larger than that of the brick, and the carbon-containing refractory originally has it. The function of preventing the penetration of slag cannot be fully exerted. Therefore, it has not been put to practical use in refining vessels that require high corrosion resistance. Therefore, in the present invention, it shows a lower porosity than the conventional carbon-containing amorphous refractory, thereby sufficiently exhibiting the difficulty of wetting to slag, which is a characteristic of carbon, and having high corrosion resistance that can be used even in refining vessels. An object of the present invention is to provide an amorphous fire-resistant material having high thermal shock resistance.

[0004]

According to the present invention, 20 to 40 parts by weight of a carbon-containing electromelting clinker having an apparent porosity of 5% or less is added to 50 to 70 parts by weight of magnesia and / or alumina clinker. The powder is blended in a ratio of 3 to 10 parts by weight.

Further, according to the present invention, as a main component of the carbon-containing electromelting clinker, 95.0-99.0% by weight of oxides having a high refractory degree such as magnesia and / or alumina, and 1.0-5 are used. It is characterized by containing 0.0% by weight of carbon.

First, a method for manufacturing the irregular refractory material of the present invention will be described. When an oxide clinker having a high refractory degree such as magnesia and / or alumina was melted and produced from a raw material, fine carbon powder was contained in an amount of 1.0 to 5.0% by weight, and carbon was uniformly mixed. It is solidified in the state and then crushed. Magnesia and / or alumina clinker 5
With respect to 0 to 70 parts by weight, 20 to 40 parts by weight of this mass as a carbon-containing electromelting clinker, and 3 to 10 parts by weight of the carbon powder of the same quality as described above in the matrix part, the carbon-containing amorphous fire resistance of the present invention is blended. Get things.

Here, the use of 50 to 70 parts by weight of magnesia and / or aluminous clinker as the main aggregate is to maintain a high refractory level which is essential as a refractory material.
If it is less than 50 parts by weight, the fire resistance is lowered, and if it exceeds 70 parts by weight, carbon is insufficient to form carbon-carbon bonds. Usually, seawater, natural or electro-melted products are used as magnesia clinker, and sintered or electro-melted products are used as alumina clinker.

Similarly, the reason for using an oxide having a high refractory degree such as magnesia and / or alumina as a main component of the carbon-containing electrolytic clinker is that sufficient strength is obtained even in a refining vessel exposed to a high temperature of 1500 ° C. or higher. Keep, molten steel,
This is because it is necessary to exhibit a difficult reactivity with the slag. Further, it is essential that the carbon-containing electromelting clinker has an apparent porosity of 5% or less in order to prevent the penetration of slag.

The content of carbon in the carbon-containing electromelting clinker is preferably 1.0 to 5.0% by weight in order to exert the effect of carbon content while maintaining a high refractory degree.
If it is less than 0% by weight, carbides are less likely to be generated between the oxide and carbon, and if it exceeds 5.0% by weight, the clinker itself has a low fire resistance. On the other hand, the content of oxide in the electromelt clinker is
It is preferably 95.0% by weight or more in order to maintain a high refractory degree, but it is necessary to be 99.0% by weight or less in order to form a bond with carbon outside the carbon-containing electromelting clinker.

The blending amount of the carbon-containing electromelting clinker in the carbon-containing amorphous refractory exhibits the effect of slag infiltration resistance due to the carbon-containing while maintaining the fire resistance and oxidation resistance of the entire amorphous refractory. Therefore, the amount is preferably 20 to 40 parts by weight, and if it is less than 20 parts by weight, the effect of carbon content is not sufficiently exhibited, and if it exceeds 40 parts by weight, the fire resistance and the oxidation resistance are lowered.

On the other hand, the blending amount of the carbon powder in the matrix portion of the carbon-containing amorphous refractory is preferably 3 to 10 parts by weight in order to form a bond between carbons while maintaining the fluidity at the time of pouring. If it is less than 3 parts by weight, carbon-carbon bonds are difficult to be generated, and if it exceeds 10 parts by weight, the fluidity during construction is adversely affected.

The carbon powder used in the present invention refers to natural or artificial black ships, mesophase carbon, carbon black, etc., and has a particle size of 500 μm or less.

Next, a method of using the carbon-containing amorphous refractory material of the present invention will be described. To the carbon-containing amorphous refractory material of the present invention, a binder, a deflocculant, water, etc. used for ordinary amorphous refractory materials are added. After sufficiently kneading, it is molded by pouring and used as a refractory lining for refining vessels.

[0014]

When the oxide raw material is melted in the electric furnace to produce the clinker, if excess carbon powder is mixed, the lump contains fine carbon when solidified. When this is pulverized, fine carbon is uniformly distributed inside and on the surface, and a carbide formed between the oxide and the carbon provides an electromelting clinker in which the oxide and the carbon are firmly bonded. Since this clinker is molten, it has a dense structure and has an extremely small apparent porosity. When this clinker is blended as a raw material for carbon-containing amorphous refractory, a bond is formed between the carbon in the clinker and the carbon outside the clinker during firing. It is possible to obtain various tissues.

As a result, this amorphous amorphous material has the characteristics of low porosity and excellent corrosion resistance, thermal shock resistance and oxidation resistance. Further, since the clinker contains carbon, the clinker itself does not contain carbon, and the slag penetration resistance of the clinker itself is relatively higher than that of the conventional refractory material in which carbon powder is added only to the matrix portion. As a result, the refractory material itself has excellent slag infiltration resistance.

[0016]

EXAMPLE As an example of the present invention, a compounding example of a carbon-containing amorphous refractory product produced by using a carbon-containing electromelting clinker, and the obtained amorphous refractory product as a refractory lining refining vessel The characteristics are shown in Table 1.

[0017]

[Table 1]

Table 1 shows the composition and apparent porosity of a carbon-containing electromelting clinker containing magnesia and / or alumina as a main component in the transverse direction, and then in the longitudinal direction, the carbon-containing electromelting clinker and normal fire resistance. The content ratio of magnesia and / or aluminous clinker used in the product, the carbon powder of the matrix part and the amount of added water, binder and peptizer are shown, and subsequently the carbon-containing amorphous fire resistance compounded in each mixing ratio. It shows the characteristics of the product. As shown in Table 1, the characteristics referred to here are, at 110 ° C., after adding a binder, a deflocculant, moisture, etc. to a carbon-containing amorphous refractory compounding example, kneading, casting and curing at room temperature. The characteristics when used as a refractory lining for refining vessels after being dried for 24 hours.

Inventive Examples 1 to 3 show the composition and characteristics of the product of the present invention, and Comparative Example 4 shows the composition and characteristics of existing materials for comparison. Here, the apparent porosity is a value after baking the dried material at 1500 ° C. for 3 hours in a reducing atmosphere.
The corrosion resistance and the slag infiltration resistance are indicated by an index based on the material of Comparative Example 4 from the results of the erosion test conducted under the conditions of 1650 ° C. × 3 hr and the slag basicity C / S = 3.
The smaller the value, the better the grade. Further, the thermal shock resistance is the number of repetitions until the stripping of the cycle of holding the material at 1400 ° C. for 15 minutes and then air-cooling for 15 minutes, as an index based on Comparative Example 4. The larger the value, the more the thermal shock resistance. Excellent in performance. Finally the oxidation resistance is 800
From the area of the decarburized layer when heated at 5 ° C for 5 hours, an index is displayed based on Comparative Example 4, and the smaller the value, the better the oxidation resistance.

As is clear from Table 1, the carbon-containing amorphous refractory containing the carbon-containing electromelting clinker according to the present invention has a lower porosity than the conventional amorphous refractory consisting of the oxide clinker and the carbon powder in the matrix. It has high slag infiltration resistance, oxidation resistance, and thermal shock resistance, resulting in high corrosion resistance.

[0021]

As described above, the blending of the electromelting clinker containing fine carbon facilitates the bonding between the electromelting clinker and the carbon in the matrix portion, and thus the amount of the volatile binder used is increased. Can be reduced,
When the carbon-containing amorphous refractory material of the present invention is used, it has excellent durability as a refractory lining refractory material having a dense structure and excellent corrosion resistance, thermal shock resistance and slag infiltration resistance.

Claims (2)

[Claims] 1. A ratio of 20 to 40 parts by weight of carbon-containing electromelting clinker having an apparent porosity of 5% or less and 3 to 10 parts by weight of carbon powder to 50 to 70 parts by weight of magnesia and / or alumina clinker. A carbon-containing amorphous refractory characterized by being blended. 2. The carbon-containing electromelting clinker has 95.0 to 99.0% by weight of an oxide having a high fire resistance such as magnesia and / or alumina as a main component, and 1.0 to
The carbon-containing amorphous refractory material according to claim 1, which contains 5.0% by weight of carbon.