JP3190116B2 - Pre-treatment method for repair work of irregular refractories - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a refractory containing graphite lining a molten metal container with an amorphous refractory.

[0002]

2. Description of the Related Art Conventionally, when repairing a lining refractory of a molten metal container with an irregular refractory, a method of simply stamping the irregular refractory along the lining refractory, or spraying a spraying refractory on the lining refractory is used. Although the method was adopted, the repaired refractory often peeled off during use. In order to overcome this drawback, as a method of improving the seizure between the surface of the refractory to be repaired and the irregular refractory for repair, a phosphate-based additive, a sodium silicate-based additive, And a method of adding clay and the like.
As disclosed in Japanese Patent Application Publication No. 7, a method of applying a sodium silicate-based mortar to the surface of a refractory to be repaired, and then repairing the surface with an amorphous refractory has been used.

[0003]

Conventionally, as a method for improving the seizure property and the hot adhesion between the surface of the refractory to be repaired and the irregular shaped refractory for repair, slag or metal slag on the surface of the refractory to be repaired has been proposed. After removing the surface, wet the surface with water, and then apply an irregular refractory for repair to which sodium phosphate, phosphoric acid, sodium silicate, clay, etc. has been added by pouring, stamping, or spraying. I have been. However, these additives to the repairable refractory have a low softening point, and when used in high temperature areas, the repairable refractory softens and melts and falls off, or the life of the repairable refractory decreases. There was a drawback to say.

A method of applying a sodium silicate mortar to the surface of a refractory to be repaired and then repairing it with an amorphous refractory has also been used.
Refractory to be repaired, such as ₂ O ₃ --SiC-C, Al ₂ O ₃ --C, and MgO-C refractories, which contain a large amount of graphite and have particularly poor wettability and Due to poor adhesion, even if the above mortar is applied, there is a defect that the adhesive strength is weak and the refractory after application is liable to peel off during use.

[0005] The present invention relates to an Al ₂ O ₃ -SiC-C
_{For 2} O ₃ -C-based and MgO-C-based refractories, develop a slurry-type adhesive that has stronger adhesive strength and further increases the adhesive strength by heating, and applies this adhesive to the above-mentioned refractories. An object of the present invention is to provide a pretreatment method for repairing and repairing irregular-shaped refractories.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on this point and found that one of a phosphoric acid-based aqueous solution, a sodium silicate-based aqueous solution, a colloidal silica-based aqueous solution, a calcium lactate-based aqueous solution, and an aluminum lactate-based aqueous solution was used. As described above, the slurry adhesive mixed with the pitch powder, the B ₄ C powder, and the SiC powder added thereto is applied to the surface of the refractory to be repaired, so that the adhesive in slurry and the surface of the refractory to be repaired, It has been found that the surface of the repair refractory can be integrated with the surface of the refractory by heating to have strong adhesiveness, and the present invention has been made based on this finding.

That is, the present invention provides a method for repairing a graphite-containing brick or amorphous refractory lining a molten metal container, a phosphoric acid-based aqueous solution, a sodium silicate-based aqueous solution, a colloidal silica-based aqueous solution, a calcium lactate-based aqueous solution, and a lactic acid-based solution. Add pitch powder to at least one type of aluminum-based aqueous solution
0 wt%, B ₄ C powder 0.5 to 2 wt%, and after a 0.5 to 2 wt% added to mixed slurry adhesive SiC powder was applied to the surface of the brick or castable refractory repair This is a pretreatment method for repairing irregular shaped refractories, characterized by constructing irregular shaped refractories.

[0008]

The function of the additive of the slurry adhesive of the present invention will be described below. The pitch softens and melts at 150 to 400 ° C, penetrates inside the refractory to be repaired containing a large amount of carbon and the irregular refractory for repair, and solidifies at 400 ° C or higher. Enhances adhesion to fixed refractories. If the amount of the pitch powder is less than 1 wt%, there is almost no effect, and if it is more than 10 wt%, the viscosity of the slurry becomes too large, and the workability is deteriorated.

B ₄ C is oxidized at 400 to 800 ° C.
A borate glass is formed to prevent oxidation of the pitch at 400 to 800 ° C. and to increase the bonding strength between the refractory to be repaired and the irregular refractory for repair. SiC is 800-12
Oxidized at 00 ° C to produce silica glass, 800-1
In addition to preventing the pitch from being oxidized at 200 ° C., the bonding strength between the repaired refractory and the repairable refractory is increased.

When B ₄ C and SiC are each 0.5 wt% or less, no effect of the bonding force is obtained, and when 2 wt% or more, no further effect of the bonding force is obtained.

[0011]

FIG. 2 shows an Al ₂ O—SiC—C brick 3
Then, the slurry-like adhesive 1 of the present invention is applied to a thickness of 1 mm,
An Al ₂ O—SiC—C-based irregular refractory ₂ of the same shape was bonded thereon and fired at 900 ° C. for 3 hours in a reducing atmosphere furnace, and set in the shearing force measuring device shown in FIG. And the adhesive force (shear force) were measured.

Table 1 shows the raw materials, liquid binders, and adhesive strengths of Examples and Comparative Examples of the slurry adhesive sample.
As is clear from Table 1, the sample of the present invention exhibited several times the adhesive strength as compared with the case of sodium silicate coating of Comparative Example 1. Further, when compared with Comparative Example 2 in which nothing was applied between the repaired refractory and the repairable refractory, the sample of the present invention showed remarkable adhesive strength.

[0013]

[Table 1]

Table 2 shows an embodiment in a steel mill.

[0015]

[Table 2]

[0016] As is clear from Table 2,
Al_TwoThe refractory life after repairing O-SiC-C bricks by conventional methods is 5 to 5.
10 ch, but the slurry adhesive of the present invention is
Al _TwoApply to O-SiC-C brick, then the same Al_TwoO-SiC-C spraying
When the refractory is sprayed, the life of the refractory is 30 to 60.
extended to ch. Al in the slag line of the ladle_TwoO_Three-C brick
The refractory life after repairing by the conventional method is 6 to 10 ch.
However, the slurry adhesive of the present invention
Part of Al _TwoO_Three-C Apply to brick, then Al_TwoO_Three-C Spray refractory
The life of the refractory to 20 to 30 ch
Lengthened.

FIG. 1 shows an example of a pretreatment method for repairing an irregular-shaped refractory according to the present invention. When the Al ₂ O ₃ -C brick in the slag line portion of the ladle 10 was melted and repaired, the slurry-like adhesive 7 of the present invention was first applied, and then the refractory sprayed with Al ₂ O ₃ -C was sprayed. It is a construction explanatory view.

[0018]

According to the pretreatment method for repairing irregular shaped refractories according to the present invention, the adhesive strength of the fixed shaped refractory for repair to the repaired refractory is increased, and therefore, the fixed shaped refractory for repair can be used during use. It does not peel off from the repaired refractory, and the life of the refractory lining of the molten metal container can be extended.

[Brief description of the drawings]

FIG. 1 is an example of the present invention.

FIG. 2 is an explanatory view of a test device of an adhesive strength of a slurry adhesive to a refractory.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Slurry adhesive 2 Repairable refractory 3 Refractory of the same material as repaired refractory 4 Sample fixing device 5 Push rod 6 Ladle lining refractory 7 Slurry adhesive of the present invention 8 Al ₂ O ₃ -C Sprayed refractory 9 Al ₂ O ₃ -C brick in slag line section 10 Ladle

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ritsu Ebisawa 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Works Chiba Works (56) References JP-A-2-224867 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/66 B22D 41/02

Claims (1)

(57) [Claims] When repairing a graphite-containing brick or amorphous refractory lining a molten metal container, a phosphate-based aqueous solution, a sodium silicate-based aqueous solution, a colloidal silica-based aqueous solution, a calcium lactate-based aqueous solution, and an aluminum lactate-based aqueous solution are repaired. to 1 or more, 110 wt.% pitch powder, B ₄ C
0.5 to 2% by weight of powder and 0.5 to 2% of SiC powder
A pretreatment method for repairing irregular-shaped refractories, comprising applying a slurry-like adhesive mixed by adding wt% to the surface of the brick or the irregular-shaped refractory and then applying the irregular-shaped refractory for repair. .