JPH0552482A - Hot gunning refractory - Google Patents

Abstract

PURPOSE:To reduce the generation of smoke upon repairing a rotary converter and the like. CONSTITUTION:The principal materials of hot gunning refractory are 100 pts.wt. of refractory filler, 2-20 pts.wt. of pitch, 0.01-5 pts.wt. of water-absorbing acrylate polymeric substances and binding agent. Said hot gunning refractory is provided with an effect of suppressing the generation of smoke upon hot gunning the refractory containing pitch. The hot gunning should be effected in a short period of time when the operation of a furnace is stopped, however, the adhering status of the gunning material can be known surely be reducing the generation of smoke and, as a result, quick repairing can be effected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray refractory material used in hot repair of refractory linings for molten metal containers.

[0002]

2. Description of the Related Art Blown refractory materials used for hot repairing refractory linings of molten metal containers such as converters and ladles are
Various materials have been conventionally known. Among them, for example, JP-A-52-127413 and JP-A-55-8464.
JP-A-55-42218, JP-A-55-4225
1, JP-A-55-130868, JP-A-55-14
No. 0768 and Japanese Patent Laid-Open No. 59-8672 propose a material in which pitch is added as a binder to a refractory aggregate.

The pitch-added spray refractory material exhibits excellent effects in hot strength and corrosion resistance by carbonizing the pitch in response to furnace heat and forming a carbon bond structure.

[0004]

However, since the pitch is contained, the smoke generated during spraying is remarkable. For this reason, there is a problem that the spraying work environment is unfavorable and the spraying condition cannot be confirmed, so that it is not possible to accurately determine the completion of repair and an appropriate spraying amount. Also,
With the recent severer furnace operation, it is the actual situation that even a pitch-added spray refractory material does not have sufficient durability.

[0005]

The present invention is a refractory aggregate 10.
A hot-spraying refractory material characterized by mainly comprising 0 parts by weight, a pitch of 2 to 20 parts by weight, a water-absorbing acrylate polymer of 0.01 to 5 parts by weight, and a binder.

The present invention has the effect of reducing the smoke concentration during spraying and improving the corrosion resistance of sprayed refractory materials containing pitch by adding an acrylate polymer.

The present invention will be described in more detail below.

The type of refractory aggregate may be the same as conventional materials,
Although not particularly limited, it is preferable to use a basic material having excellent corrosion resistance as a main material. As a basic material,
For example, it is a sintered product or an electro-melted product of magnesia, dolomite, magnesia-calcia, calcia and the like. This may be combined with non-basic properties such as spinel, alumina, zircon, zirconia, silica, silica and silicon carbide.

As is well known, pitch is a residual oil in a kettle obtained by dry distillation of coal, petroleum and the like. Either crushed particles or spherical particles can be used, but spherical particles excellent in hydrophilicity are preferred. The component is a residual coal rate of 40 to 7
0 wt% is preferable. Not only the pitch is kept as it is, but also, for example, JP-A-55-42218 and JP-A-55-4.
As seen in No. 2251 and the like, it may be added in the form of granules mixed with refractory fine powder. Two or more kinds of pitches having different softening points may be used in combination, as in JP-A-59-8672.

If the proportion of the pitch is less than 2 parts by weight with respect to 100 parts by weight of the refractory aggregate, the carbon bond structure is not sufficiently formed, resulting in poor corrosion resistance. If it exceeds 20 parts by weight, the carbon content becomes too large and the oxidation resistance is poor.

The water-absorbing acrylate polymer is generally known as a water-absorbing agent for sanitary products such as disposable diapers. On the other hand, the present invention has the effect of reducing smoke density during spraying and improving durability in the sprayed refractory material to which pitch is added.

The sprayed refractory material receives furnace heat on the surface to be repaired to evaporate the working water, and then carbonizes the pitch. When the construction water is lost due to evaporation, the temperature rises and the smoke from the pitch becomes noticeable. The sprayed refractory material of the present invention, although the absolute amount of fuming does not change, suppresses the rapid evaporation of construction water due to the water retention property of the water-absorbing acrylate polymer, and due to its cooling action, it has been found in conventional materials. Prevents intensive smoking in a short time. As a result, the smoke density can be reduced to such an extent that it does not hinder the confirmation of the spraying condition.

Further, by preventing intensive smoke emission, the gas pressure in the refractory structure due to smoke emission is reduced, the sprayed refractory material is prevented from becoming porous and the adhesive strength is reduced, and the durability is improved. Can be planned.

The water-absorbent acrylate polymer is, for example, a potassium acrylate polymer or a sodium acrylate polymer. Although the specific properties thereof are not particularly limited, for example, water absorption capacity (g / g / deionized water) 100 to 5
00, water absorption rate (sec) 1-80, gel strength (dyn / c)
m2) 1 to 7 × 104, average particle size (μm) 10 to 500
Is preferred.

If the proportion of the water-absorbing acrylate polymer is less than 0.01 parts by weight with respect to 100 parts by weight of the fire-resistant aggregate, the effects of reducing smoke and improving the corrosion resistance are not recognized, and if it exceeds 5 parts by weight, the fire-resistant material is increased. The structure becomes porous and the corrosion resistance is poor.

Based on the compounding composition of Example 1 in Table 2,
The graph of FIG. 1 shows the relationship between the smoke generation time and the addition amount of the water-absorbing acrylate polymer by changing only the addition amount of the water-absorbing acrylate polymer. It is confirmed that the smoke generation time is prolonged by adding the water-absorbing acrylate polymer. As the smoke generation time is longer, the smoke generation is not concentrated in a shorter time, so that the smoke generation concentration during the spraying work is reduced.

The relationship between the hot strength and the amount of water-absorbing acrylate polymer added is shown in the graph of FIG. As a result of this graph, improvement in hot strength is confirmed by the addition of the water-absorbing acrylate polymer. Hot strength correlates with improved corrosion resistance. Since the water-absorbent acrylate polymer is a depleting substance, the addition of a large amount returns the corrosion resistance and decreases.
The amount added should be limited within the scope of the present invention.

The smoke generation time shown in FIG. 1 and the hot strength shown in FIG. 2 were both measured by the same method as the test shown in the section of Examples below.

The type of binder and the amount of addition thereof may be the same as those of conventional materials. For example, as the binder, soda phosphate,
Calcium phosphate, magnesium phosphate, potassium phosphate, aluminum phosphate, and other phosphates, sodium silicate
Silicates such as da, potassium silicate, lithium silicate,
One or more selected from sulfates such as magnesium sulfate and aluminum sulfate and alumina cement are used. The ratio with respect to 100 parts by weight of the refractory aggregate is, for example, 2 to 10 parts by weight.

In addition, if necessary, a hardening agent, a thickener, a metal powder, a phenol resin particle, a carbon powder, a refractory ultrafine powder, a short fiber, a thickener and the like may be added. The curing agent is
Examples include calcium hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, lithium carbonate, gypsum, Portland cement, dicalcium silicate, soda fluoride. Examples of the thickener include clay, bentonite, organic paste, CMC and the like. The addition amount of both the hardening agent and the thickening agent is 10 based on 100 parts by weight of the refractory aggregate.
It is not more than 0.5 parts by weight, preferably 0.5 to 5 parts by weight.

The spraying method is the same as the conventional material. That is, about 15 to 35% by weight of construction water is added to the entire composition by external coating, and sprayed on the surface to be repaired. The spraying method is roughly classified into a wet method of spraying the composition with the working water added from the beginning and a dry method of adding the working water to the composition in the nozzle. Therefore, the dry method is preferable.

[0022]

EXAMPLES Table 2 shows examples of the present invention and comparative examples thereof.

[0023]

[Table 1]

[0024]

[Table 2]

The water-absorbent acrylate polymer used in each example was obtained from a commercial product, and its various properties are shown in Table 1. The pitch was used in the following three types.

Spherical pitch; softening point 120 ° C., residual carbon ratio 60
Sphericalized wt% pitch. Pitch-magnesia mixed particles: Pitch having a softening point of 80 ° C. and a residual coal ratio of 45 wt% and sintered magnesia fine powder are mixed at a weight ratio of 1: 1 and spheroidized.

Pulverized ground powder; softening point 80 ° C., residual coal rate 45
A product obtained by pulverizing wt% pitch.

The test method is as follows.

Smoke generation time: 100 g of a spraying material added with 15 wt% of moisture was applied on a basic brick installed in an electric furnace heated to 1200 ° C., and the time from smoke generation to completion was measured. did. The longer the smoke generation time, the smaller the smoke concentration.

Hot strength: Cast into a shape of 30 × 30 × 120 mm, put in an electric furnace after heating to 1400 ° C., hold for 1 hour, and then measure hot bending strength at 1400 ° C. and a span of 100 mm. ..

Actual machine test: Used and tested for hot spraying of a 300 t converter. In the smoke concentration test, the smoke concentration was visually measured for 3 minutes from the start of spraying. If the smoke density is low, the work environment and construction efficiency will be improved. In the durability test, the number of durable charges of the sprayed refractory material was obtained.

Smoke generation time In all the examples of the present invention, the smoke generation time is as long as 10 minutes or more. Therefore, the smoke density is low. Comparative Example 1 is a conventional type material, has no added water-absorbing acrylate polymer, and has a short smoking time.

Hot strength is correlated with corrosion resistance. The examples of the present invention have high hot strength. Comparative Example 1 without addition of water-absorbing acrylate polymer, Comparative Example 2 without addition of pitch,
In Comparative Example 3 in which the amount of the water-absorbing acrylate polymer added is too large and Comparative Example 4 in which the amount of pitch added is too large, the hot strength is small.

Also in the actual machine test, the examples of the present invention exhibited effects such as low smoke density and excellent corrosion resistance. In Comparative Example 2, there was no problem of smoke generation because no pitch was added, but since the carbon bond structure was not obtained, the hot strength was small, and there was a concern that the durability would be significantly inferior. ..

[0035]

[Effect] The effects of the pitch-containing sprayed refractory material of the present invention are listed below.

The smoke density from the pitch is reduced, and the working environment at the time of spraying can be improved.

Hot repairs must be carried out in a short time when the furnace is idle. By reducing the smoke concentration, it is possible to accurately grasp the state of adhesion of the sprayed refractory material and the judgment of repair completion. As a result, it becomes possible to efficiently perform the spraying work within a short time.

The pitch has an effect of forming a carbon bond structure, but in the conventional material, the gas pressure generated from the pitch causes the sprayed refractory material to become porous and the adhesive strength to be lowered. In the present invention, no gas is rapidly generated, the gas pressure in the refractory material structure is lowered, and the durability is improved as compared with the conventional pitch-added material.

[Brief description of drawings]

FIG. 1 is a diagram showing the results of investigating the relationship between the amount of water-absorbing acrylate polymer added and the smoke generation time.

FIG. 2 is a diagram showing the results of an investigation of the relationship between the amount of water-absorbing acrylic acid polymer added and the hot strength of the refractory material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Yukihiko Goto 1-3-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Harima Ceramics Co., Ltd. No. Harima Ceramics Co., Ltd.

Claims (1)

[Claims] 1. A refractory aggregate of 100 parts by weight and a pitch of 2 to 20.
A hot-spray refractory material, which is mainly composed of parts by weight, 0.01 to 5 parts by weight of a water-absorbing acrylate polymer, and a binder.