JP2862979B2 - Refractory for lining repair of mixed iron cars - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a refractory, and more particularly to a refractory for repairing a lining of a mixed iron wheel.

[Conventional technology]

In recent years, mixed-iron cars used as transport containers for hot metal from blast furnaces have also been used as reaction vessels for pretreatment for dephosphorization and desiliconization. Conditions are only getting worse.

Conventionally, a method of repairing by replacing a new refractory in accordance with the wear shape of such a worn portion has been performed, but in such a method, it is necessary to cool the mixed iron wheel once and then perform the replacement work. In addition, there is a problem in that the operating cost of the piggyback car is reduced, and that the replacement work requires a lot of time, and the repair cost is increased.

Therefore, in recent years, a method of repairing a worn part by spraying by spraying an amorphous refractory on a remaining brick has been performed in order to shorten a time required for the repair work.

As yet another method, a method has been developed in which a material (amorphous refractory) is vibrated using a vibrating iron and the refractory is applied while imparting thixotropic properties [Refractory (S55, issued in September) 32
−513], for example, Japanese Patent Publication No. 2-10844 discloses a method of performing construction using a refractory containing ultrafine silica powder and SiC fine powder.

FIG. 1 is a longitudinal sectional side view schematically showing a state of wear and repair of a refractory lining of a mixed iron car. Mixed iron wheel 10 shown in FIG.
The lining 5 of the lining brick 2 is mainly damaged by thermal shock and abrasion at the time of receiving iron, and the slag line 4 is also mainly used by the molten iron for stirring and flux for dephosphorization and desiliconization during pretreatment. Due to erosion of slag and the like, both are worn deeper than other parts. A repair material made of an amorphous refractory is formed in the worn portion to form a repair material layer 1 by spraying or using a vibrating iron, and the original lining brick is restored to the profile 3.

[Problems to be solved by the invention]

By the way, in the repair method by spraying, the working environment is deteriorated due to dust generation at the time of the spraying, and the construction body obtained by spraying is porous, so that the slag can easily penetrate into the repaired part. In addition, it may not be possible to secure sufficient durability at the repair location, for example, because a predetermined mechanical strength cannot be obtained.

On the other hand, in the repair method disclosed in Japanese Patent Publication No. 2-10844, there is no concern about deterioration of the working environment due to the dust generation, but the refractory provided in the repair method has a hot property in a high temperature range, Unsatisfactory workability and adhesiveness with the lining remaining brick, and when repairing a worn area in a narrow range, peeling wear occurs at the repaired part due to volume change of the construction body due to thermal expansion. There are cases.

In view of the above circumstances, the present invention is a mixed iron wheel that has excellent hot strength at high temperatures, workability, excellent adhesion to lining remaining brick, excellent volume stability, and improved overall durability. The purpose of the present invention is to provide a refractory for lining repair.

[Means for solving the problem]

The present invention employs the following means in order to solve the above problems.

That is, in a refractory for lining repair of a mixed iron car constructed by a vibrating iron, 80 to 95% by weight of a refractory aggregate and 5
Spread ultrafine silica powder on a mixture containing ~ 20% by weight
0.5 to 2% by weight, and organic polymer-based preservatives
It is a refractory for repairing the lining of a mixed iron wheel, with 0.2% by weight added.

(Operation)

In the above configuration, the refractory aggregate may be a known material depending on the material of the refractory lining of the mixed iron wheel. For example, high-melting alumina, sintered alumina, bauxite, van earth shale, chamotte, etc. Alumina raw material is used alone or in combination of plural raw materials.

In the present invention, the fine particles (particle diameter: 350
μC), the fine structure of the repaired part reduces the penetration of slag, improves the corrosion resistance of the flux for dephosphorization and desiliconization to slag, and has a low coefficient of thermal expansion. Provides volume stability.

The compounding amount of the SiC fine particles is preferably 5 to 20% by weight with respect to the compounding amount of the refractory aggregate of 80 to 95% by weight. If the compounding amount of the SiC fine particles is less than 5% by weight, a sufficient improvement in corrosion resistance can be expected. On the other hand, if the amount exceeds 20% by weight, the effect corresponding to the amount cannot be expected and the cost is disadvantageous.

By adding ultrafine silica powder and a shape-retaining agent of a water-soluble organic polymer to the mixture of the refractory aggregate and SiC fine particles, spalling resistance at higher temperatures than conventional materials, volume stability, and heat A construction having excellent hot properties such as inter-bending strength can be obtained.

In addition to the effect of the shape retainer described below, the bearing effect of the ultrafine silica powder, that is, the substantially spherical ultrafine silica powder, improves the fluidity of the material at the time of construction, and improves the workability at the time of construction with a vibrating iron.

In addition, the area of the bonding surface is increased by the silica ultra-fine powder being effectively dispersed and arranged on the bonding surface between the construction body and the lining residual brick, which is excellent not only after sintering the construction body but also during construction. Shows adhesion.

The silica ultrafine powder preferably has a particle diameter of 0.1 μm or less, and the amount added is 100% by weight of the refractory aggregate,
If the amount is less than 0.5% by weight, the desired effect cannot be obtained. If the amount exceeds 2% by weight, the workability during kneading and repair work and the thermal expansion coefficient of the construction body are reduced. As a result, the spalling resistance decreases.

As the shape-retaining agent (water-soluble organic polymer compound), carboxymethyl cellulose, polyacrylamide-based polymer compound, etc. can be used in addition to the methyl cellulose used in this example, and workability during construction is improved. I do. The addition amount of the above shape-retaining agent is preferably from 0.01 to 0.2% by weight, and if it is more or less, proper workability cannot be obtained.

〔Example〕

 Hereinafter, the present invention will be described based on examples.

The upper column of Table 1 shows the composition of each of the refractory for lining repair according to the present invention as Examples 1 to 6 and the conventional refractory for lining repair as Comparative Examples 1 to 7, respectively. Shows the physical property values of test pieces cut out from construction materials obtained by repairing each lining repair refractory with an actual furnace model made of Al ₂ O ₃ —SiC—C brick using a vibrating iron.

In the table, the bond strength was measured by measuring the bond shear strength of a 65 × 114 × 230 mm specimen, and the corrosion resistance index was measured by lining each specimen in a high-frequency induction furnace and using a ratio of 1: 1 of pig iron and hot metal pre-treated slag. After performing a test at 1500 ° C. for 3 hours, the amount of wear of each specimen was expressed as a relative numerical value, with the amount of wear of Comparative Example 7 being 100. Further, the values of the hot bending strength and the expansion / shrinkage ratio after 1 hour at 1400 ° C. were measured. The workability was indicated by を for good, Δ for good, and x for bad.

The physical properties shown in the lower column of Table 1 show that all of the products of Examples of the present invention have a better balance of each physical property value than the comparative examples of the conventional products, and are excellent in workability or overall durability. .

In addition, as a result of repairing using a refractory according to the present invention in a 250 ton mixed-iron car, the construction thickness was 100 to 120 mm and then 300 ch
And tapping was repeated.

[Effects of the Invention] As described above, according to the refractory for repairing a lining of a mixed iron wheel according to the present invention, the hot strength in a high temperature range as compared with a conventional refractory,
It is excellent in workability, adhesiveness to lining brick, and volume stability, and can improve overall durability, thereby contributing to reduction of maintenance cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view schematically showing a state of wear of a refractory lining of a mixed iron wheel.

Claims (1)

(57) [Claims] 1. A refractory for repairing a lining of a mixed iron wheel, which is repaired by using a vibrating iron, comprising: a mixture of 80 to 95% by weight of refractory aggregate and 5 to 20% by weight of SiC fine particles; 0.5 to 2% by weight of ultra-fine silica powder and 0.01 to 0.2% by weight of organic polymer
A refractory for repairing lining of a mixed iron wheel, characterized by adding: