JPH07106947B2 - Amorphous refractory for powder type dry hot repair - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a repair material for hot repairing a lining portion of a molten metal container such as a converter, a blast furnace, a ladle, a vacuum degassing device.

[0002]

2. Description of the Related Art In a molten metal container such as a refractory in a converter, molten metal reacts violently with oxygen, so that a portion where a large amount of corrosion occurs due to high temperature and agitation occurs. This eroded part is repaired hot, but if the repair time becomes long, the operability of the converter operation decreases, so the actual condition is that the furnace lining must be repaired while the temperature is considerably high. There was As the hot repair material, a basic refractory material to which tar pitch is added is mainly used. Further, as a powdery hot repair material, repair materials using a fire resistant aggregate with a phenol resin or a granular pitch as a binder are disclosed in JP-A-58-110473 and JP-A-58-26080.
No. 62-238316.

[0003]

In recent years, with the shortening of processing time in a molten metal container such as a converter, shortening of the time until completion of baking repair has become an important issue.

The above-mentioned conventional repair material has the following problems.

(1) In the repair material disclosed in Japanese Patent Application Laid-Open No. 58-110473, since the amount of the solid phenol resin added is too large, heat is received and the carbon bond shrinks in the process of liquefaction → curing → carbonization. As a result, it causes warpage and poor adhesiveness. Further, there is a problem that the repaired material itself flows due to the heat-retention heat of the furnace, so that the damaged portion with a slope such as the tap hole of the converter or the slag line cannot be repaired.

(2) In the repair material disclosed in JP-A-58-26080, too, the amount of solid phenol resin (whether it is a resole type or a novolac type) to be added is too large. There's a problem.

(3) In the repair material disclosed in Japanese Patent Application Laid-Open No. 62-238316, the combination of the granular pitch and the powdery resol-type phenol resin causes the inclination of the converter tap hole, slag line, etc. Although it is a repair material that exhibits shape retention in the damaged part, the resole-type phenol resin has a drawback that the filling property of the repair material is inferior because of rapid curing by heat.

The above-mentioned conventional repair material does not have shape retention or adhesiveness capable of repairing a curved portion of the tap hole of a converter or a damaged portion having an inclination such as a slag line,
In addition, the material had a low filling property.

The present invention has been made for the purpose of improving the above-mentioned problems, and the main point is that the repair material, which is powdery at room temperature, receives heat from the high temperature portion, and the particulate matter is softened and even in the inclined portion. It is to fill the repaired part closely.

[0010]

[Means for Solving the Problems] 100 parts by weight of a refractory material as a hot repair material for a molten metal container, a compounding ratio of a granular novolac type phenol resin and a granular pitch of 1: 4 to 2:
The present invention has been completed successfully by solving the above-mentioned problems by adding 12 to 24 parts by weight in an external range within the range of 3.

The refractory material used in the present invention is acidic or neutral such as alumina and silica, or carbides, nitrides or magnesia, dolomite, and one or two carbon materials depending on the type of molten metal container and the place of use.
It is a mixture of two or more species. This carbon material is added when the amount of residual coal in the construction is insufficient due to the amount of residual coal from the novolac type phenolic resin and pitch in consideration of operating conditions.
Addition of carbon material improves the quality by absorbing thermal expansion and contraction of refractory at high temperature and improving corrosion resistance due to impermeability of molten metal layer, thus reducing the amount of repair material used and the repair frequency. . In particular, when repaired with the same material as the furnace lining material, it becomes a refractory that is integrated after repair and peeling off becomes difficult.

The amount of the granular novolac type phenolic resin and the granular pitch used is preferably larger than that of the granular novolac type phenolic resin. As a result of examining the use ratio, the granular novolac type phenolic resin and the granular pitch are used in a ratio of 1 It is preferably within the range of: 4 to 2: 3. This is because, if the content is out of these ranges, the shape retention immediately after the construction and the adhesion of the construction body are poor, the early curing cannot be obtained, and the physical properties of the repair material deteriorate (FIG. 1). It is desirable to change the usage rate in consideration of the inclination of the repaired part.

The addition amount of the granular novolac type phenolic resin and the granular pitch is 1 in total with respect to 100 parts by weight of the refractory material.
The amount is 2 to 24 parts by weight, and if it is less than 12 parts by weight, there is no heat filling property in the work and the fluidity is low, so that the adhesiveness to the repaired surface is deteriorated. Further, when the amount is more than 24 parts by weight, the fluidity becomes large, so that the shape retaining property is lost in the inclined portion and the physical properties of the construction work are deteriorated to deteriorate the working environment.

The granular novolac type phenolic resin added to the refractory material has a softening point of 100 ° C. or lower, preferably 50.
It has a number average molecular weight of 300 to 1000 at a temperature of not less than 80 ° C and not more than 80 ° C. When the number average molecular weight is 300 or less, the melting point is low and it does not become a solid. When the number average molecular weight is more than 1000, the thermal softening property is poor, and thermal expansion and contraction in carbonization are large and cause peeling. Regarding the particle size, considering the surface area for obtaining the heat softening property and the dispersibility, an average particle size of 0.1 mm or more and 3.0 mm or less is suitable. If the average particle size is less than 0.1 mm, the surface area is large to obtain the same thermal softening property, so the bulk becomes large, the powder filling property when injecting the material is poor, the thermal softening flow is not sufficient, and it is partially porous. This is because it becomes an organized body. If it is 3.0 mm or more, the dispersibility will be poor.

The novolac type phenolic resin melts when it comes into contact with a high temperature part, and at that time absorbs heat from the high temperature part.
This heat absorption cools the bonding surface, which is effective for bonding and ensures bonding. The gas generated at this time has no concern about explosion or the like because the repair material is powdery.

The powdery pitch added to the refractory material may be either petroleum-based or coal-based, and it is necessary that the average pitch is 0.2 mm or more. Pitch softens and flows by furnace heat to form a carbon bond, but if the average particle size is less than 0.2 mm, the flow range is narrow because the particle size is small, and carbon bond formation is particularly poor.

As described above, in the present invention, since it is a non-aqueous system, it is not necessary to dry it to evaporate water. In addition, the repair time was shortened and the heat filling property was improved.

[0018]

Function The repair material applied to the molten metal container having the heat of the furnace softens both the granular novolac type phenolic resin and the granular pitch into a liquid. However, since the novolac type phenolic resin and the pitch are not compatible with each other, the fluidity of the repair material as a whole is not improved, and it can be molded into the shape of the repaired portion having an initial curved surface. Therefore, it has a shape retention property that can be repaired even in the inclined portion.

However, since both the pitch and the novolac type phenolic resin are liquid, it is possible to move the refractory aggregate in a small range microscopically, the filling property is improved, and the adhesion with the repaired portion is possible. Even at the interface, both of these liquids flow in their respective small ranges, so that the adhesive force can be improved.

Furthermore, the thickness of the repair material is reduced as a result of the above effects. In other words, the distance from the repaired part that has heat is shortened, which is effective in shortening the curing time (FIG. 1).

That is, in the curing process of this repair material, by using a binder in which granular novolac type phenolic resin and pitch are used in combination, it is possible to maintain the work in a short time within a range that does not affect the operation of the molten metal container. It imparts shape and adhesiveness, and further develops the adhesiveness, filling property and strength required as a repair material.

[0022]

EXAMPLES Next, examples of the present invention will be described together with comparative examples.

Baking materials having the composition as shown in Table 1 (Examples 1 to 6 of the present invention, Nos. 1 to 5 as comparative examples) were prepared and the workability (presence or absence of flattening, baking thickness, Each test item of physical properties (apparent porosity, bulk specific gravity) shape retention adhesiveness (hot adhesive strength) was examined. Of these, Comparative Example No. Nos. 1 to 3 show that the ratio of the granular novolac type phenolic resin and the granular pitch used is outside the range of the present invention. No. 4 shows a conventional type baking material using a granular resol type phenol resin and a granular pitch. Reference numeral 5 denotes a conventional type baking material using a granular resol type phenol resin.

[0024]

[Table 1]

Test method 1) Workability: A sample of 500 g was heated at 1000 ° C. in a small kerosene furnace.
It was placed in a castable plate of 400 × 300 × 30 mm held in the above, and the presence or absence of flattening due to flow, the baking thickness, and the baking time were measured.

2) Physical properties: The material after the above test is JIS
Apparent porosity and bulk specific gravity were measured according to R 2205-74.

3) Shape retention: The castable plate used in the workability test was tilted at 30 °, heated to 1000 ° C., and 500 g of a sample was put in to investigate the shape retention.

4) Adhesiveness: 12 heated to 1000 ° C.
22φ × 20 (h) on 0 × 120 × 30mm brick
10 g of the sample was put into an mm steel pipe, and the adhesive strength after 5 minutes was measured.

As is clear from the results in Table 1, Example No. 1 in which the granular novolac type phenolic resin and the granular pitch were used in combination. Comparative Examples Nos. 1 to 6 have high adhesive strength, short baking time, and excellent filling property. Comparative Examples Nos. 1 to 3 and a combination of granular resol-type phenolic resin and granular pitch. Comparative Example No. 4 using a granular resol type phenolic resin. No. 5 is inferior in adhesive strength and filling property.

FIG. 1 is a diagram showing the relationship between the ratio of the granular novolac type phenolic resin and the granular pitch, the baking thickness, and the apparent porosity. The filling property is improved by adding a small amount of granular novolac type phenolic resin. This proves the superiority of the present invention.

[0031]

EFFECTS OF THE INVENTION The hot repair material of the present invention is melted by using a granular novolac type phenolic resin which is rapidly hardened with softening, and a granular pitch which is softened and fluidized once and is further carbonized by heating. The hot repair of the metal container can be effectively performed, and the effect of contributing to the improvement of productivity by obtaining a dense work body is extremely large.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the ratio of the granular novolac type phenolic resin and the granular pitch, the baking thickness, and the apparent porosity.

Claims (1)

[Claims] 1. A softening point of 1 with respect to 100 parts by weight of a refractory material.
Dry hot repairing in powder form, characterized in that 12 to 24 parts by weight of external addition is carried out within the range of the compounding ratio of the granular novolac-type phenolic resin and the granular pitch, which is 00 ° C or lower, in the range of 1: 4 to 2: 3. Unshaped refractory for use.