JP2549169B2 - Hot repair material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hot repair material used in various industrial furnaces such as a converter, an AOD furnace, an electric furnace, and a ladle.

[Conventional technology]

In recent years, in industrial furnaces, in order to improve production efficiency,
The refining time and downtime have been shortened and the usage conditions have become extremely severe. For example, in the case of a converter, in order to meet these demands, as well as to meet the demands for higher grade steel,
Top-bottom blow refining is becoming more and more used, and the life of refractory linings is shortened. In particular, significant lining damage is seen around the furnace bottom and tuyere.

Conventionally, when such partial damage of the furnace occurs, the repair material is put into a high temperature atmosphere when the furnace is at rest, and the repair material is baked by the heat of the furnace, that is, the life of the furnace is improved by hot repair. Is being extended.

For the above hot repair materials, after being put into the furnace, it adheres with high strength to the damaged area covered by the softening and the initial fluidity that quickly softens and spreads to the damaged area. It is required to satisfy both the characteristics of (seizure) and the seizure property, and in order to impart such characteristics to the hot repair material, a carbonaceous raw material such as pitch or tar as described below is blended. There is. These carbonaceous raw materials are softened by the heat of the furnace, flow with aggregate particles to quickly cover the damaged area, and after the lapse of a predetermined time, the carbon bond due to the disappearance of volatile components ensures the required seizure property. I am trying.

In addition, considering the handling of the charging work, the above hot repair material
The kneaded raw materials may be formed into a lump (a shape similar to what is called “bean charcoal”) that is collected in a predetermined amount. This kind of lump formation is easy and can be put into the furnace. At the same time, shape retention is also required to make it difficult for the hot repair material to lose its shape after the above-mentioned ingot formation.

As the hot repair material used for hot repair, for example,
It is known that a refractory raw material such as magnesia or dolomite is added with tar, pitch or the like and heated and kneaded.

Further, for example, as disclosed in JP-A-63-139068, a granular phenol resin and a granular pitch are used in combination, the phenol resin is dissolved, and the boiling point is lower than the softening point of the phenol resin and the pitch. It has been proposed to add and mix an organic solvent having

[Problems to be Solved by the Invention]

Nowadays, there is a strong demand for higher production efficiency, and it is required to shorten the downtime of the furnace as much as possible to increase the operating rate of the furnace and use the furnace heat as effectively as possible for the next refining. ing. For this reason,
There is also an increasing demand for shortening the repair time for repairing furnaces at rest.

However, the conventional hot repair material using tar, pitch, etc. as a binder, or the hot repair material using a granular phenol resin and granular pitch together has a slow baking speed, and is aimed at shortening the repair time. I feel a lot of dissatisfaction. Therefore, the idea was to start operation with insufficient baking due to furnace heat, and to proceed with baking with the heat during operation, but in this case, within a short time after starting operation. It was found that the repair material peeled and fell off, and the repair effect was lost.

Further, in order to improve the above-mentioned printing speed, JP-A-53-7520
As described in Japanese Patent Publication No. 7, the polymerization of carbonaceous raw materials such as tar and pitch by adding to the raw material of refractory bricks, which is premised to be formed into a shape suitable for furnace construction using a mold. It is also possible to promote the heat treatment and improve only the seizure property.

However, the invention described in JP-A-53-75207 is premised on being dried or fired after the above-mentioned molding, and if it is directly applied to the hot repair material of such an invention, it is affected by the action of sulfur. The initial liquidity will decrease.

In particular, the carbonaceous raw material (tar, pitch) in the hot repair material plays a role of causing the aggregate particles to quickly flow to the damaged portion immediately after the furnace is charged as described above. Since a larger amount than the pitch described in (3) is blended, the above tendency becomes remarkable, and it is difficult to immediately adopt.

The present invention has been made in view of the above circumstances,
While maintaining good initial fluidity immediately after charging in the furnace, it has a good bakeability that can shorten the time until baking, and is intended to maintain a predetermined shape that was given before charging well. is there.

[Means for solving the problem]

The present invention is applied to a hot repair material which is kneaded into raw materials and then put into a furnace without performing a baking treatment, wherein the basic aggregate is 60 to 90% by weight and the solid pitch is 15 to 40% by weight. , And powdered sulfur to the outside of 0.05 to 1.5% by weight.

Further, as a wetting agent, at least one kind of liquid phenol resin, polyhydric alcohol such as ethylene glycol, kerosene, heavy oil, anthracene oil, and water is externally applied to 2 to 10% by weight.
It is also desirable to add.

[Action]

The basic aggregate used in this invention may be one generally used as a basic aggregate,
Examples thereof include magnesia clinker, dolomite clinker, spinel clinker, magcro clinker, and electromelted products thereof.

Further, in the present invention, the solid pitch acts as a fluidizing agent that enhances the fluidity of the repair material when the repair material is attached to the damaged portion. That is, the solid pitch is softened by being heated by the heat of the furnace to give the repair material high fluidity. Further, the solid pitch functions as a binder as the volatile components are volatilized and solidified as the baking proceeds and carbonized.

As described above, the solid pitch defined in the present invention not only ensures the initial fluidity immediately after being introduced into the furnace and the seizure property with respect to the furnace bottom (wall), but by blending with the wetting agent described later, The kneaded material after kneading is given an appropriate viscosity, and also has the effect of improving the shape retention of the lump-shaped hot repair material formed prior to the operation of charging into the furnace. If liquid pitch (preheated coal tar pitch) is used in place of the solid pitch, the viscosity of the kneaded material is reduced, and the shape retention after molding is significantly impaired, which is not preferable.

The addition amount of solid pitch is preferably 10 to 40% by weight. If the addition amount of the solid pitch is less than 10% by weight, the fluidity of the repair material becomes insufficient, the repair material becomes lumpy and the damaged portion cannot be widely covered, and the hot strength becomes low, which is not preferable. Further, if the addition amount of the solid pitch is more than 40% by weight, the porosity increases and the corrosion resistance decreases, which is not preferable.

Further, in the present invention, the powdered sulfur functions to promote the polymerization of pitch, accelerate the solidification of pitch, and enhance the strength after baking.

The amount of powdered sulfur added is preferably 0.05 to 1.5% by weight.
If the amount of powdered sulfur added is less than 0.05% by weight, the effect is small, and particularly the effect of increasing the strength after baking is significantly reduced, which is not preferable. Further, if the amount of powdered sulfur added is more than 1.5% by weight, the fluidity is significantly reduced, which is not preferable.

The hot repair material according to the present invention is used after being mixed with a basic aggregate, solid pitch and powdered sulfur and molded.

In this invention, the addition of wetting agents is not hindered.

As the wetting agent, one of liquid phenol resin, polyhydric alcohol such as ethylene glycol, kerosene, heavy oil, anthracene oil and water may be used alone, or two or more of them may be used in combination. You may.

The total amount of the wetting agent added is preferably 2 to 10% by weight. If the total amount of the wetting agent added is less than 2% by weight, it hinders the ingot-making process before the addition, and if it is more than 10% by weight, the repair material will be significantly softened and will not be retained after molding. This is not preferable because the formability is significantly impaired.

In the present invention, particularly when a liquid phenol resin is used as the wetting agent, the strength after molding can be increased, which is advantageous, and the moisturizing property can also be obtained.

Further, in the present invention, particularly when ethylene glycol is added as a wetting agent, it is advantageous because the filler at the time of molding can be increased and the moisturizing property can be obtained.

As described above, the present invention is the above basic aggregate, solid pitch,
By kneading powdered sulfur with the above composition, the initial fluidity and seizure of the hot repair material that is put into the furnace in a pre-cast form are improved, and the addition of a wetting agent balances the shape retention. It can be maintained well and highly.

[Examples and Comparative Examples]

(A) Spreading test A magnesia clinker having a particle size of 3 to 1 mm, a magnesia clinker having a particle size of 1 mm or less, a pitch of 5 mm or less, and a powdered sulfur are compounded according to the composition shown in Examples 1 to 5 in Table 1, After adding ethylene glycol or a liquid phenolic resin together with it as required, it was molded into a cube having a side of 40 mm to obtain samples for each spreading test according to Examples 1 to 5.

Similarly, a magnesia clinker having a particle diameter of 3 to 1 mm, a magnesia clinker having a particle diameter of 1 mm or less, and a pitch having a particle diameter of 5 mm or less are blended in accordance with the blending composition shown in Comparative Example 1 or Comparative Example 2 in Table 1 as necessary. Then, ethylene glycol and liquid phenol resin were added thereto, and thereafter, each side was molded into a cube of 40 mm to obtain each spreading test sample according to Comparative Example 1 or 2.

The spread test samples of the hot repair materials according to Examples 1 to 5 and Comparative Examples 1 and 2 thus obtained were each subjected to 1200 ° C.
Into the crucible C preheated in the furnace of No. 1 and subjected to a spreading test for checking the fluidity at 1200 ° C., the results shown in FIG. 1 were obtained.

As is clear from FIG. 1, the fluidity decreases as the amount of sulfur added increases.

The shape and dimensions of the crucible C used in this spreading test are as shown in FIG.

(B) Strength Test Next, according to the composition shown in Example 4 and Example 5 in Table 1, a magnesia clinker having a particle size of 3 to 1 mm and a particle size of 1
mm magnesia clinker of 5 mm or less, pitch of 5 mm or less of particle size, powdered sulfur, ethylene glycol and liquid phenol are mixed and molded into a rectangular parallelepiped of 77.5 mm × 40 mm × 70 mm for each strength test according to Examples 4 and 5. A sample was obtained.

In addition, according to the composition shown in Comparative Example 2 in Table 1, magnesia clinker having a particle diameter of 3 to 1 mm, magnesia clinker having a particle diameter of 1 mm or less, pitch having a particle diameter of 5 mm or less, ethylene glycol, and liquid phenol resin were added, 7
A strength test sample according to Comparative Example 2 was obtained by molding into a rectangular parallelepiped having a size of 7.5 mm × 40 mm × 70 mm.

Each strength test sample of the hot repair material according to Example 4, Example 5 or Comparative Example 2 thus obtained was put into a casting mold M preheated to 1200 ° C., and a predetermined time (here, 5 minutes,
After holding for 10 minutes or 20 minutes), it was taken out, cut into a cube having a side of 40 mm, and the expression intensity was measured. The results shown in FIG. 3 were obtained. As is clear from FIG. 3, the hot repair material according to Example 4 or Example 5 is superior to the hot repair material according to Comparative Example 2.

The dimensions of the shape of the casting mold M are as shown in FIG.

(C) Practical test 180t A hot repair material having the composition shown in Example 4 of Table 1 was put into the repaired part of the vertical blowing converter and baked, and the time required for the baking was measured. The operation was repeated and the durability was examined. Similarly, 1t of hot repair material having the composition shown in Comparative Example 2 in Table 1 was put into the repaired part of the 180t vertical blowing converter and baked, and the time required for the baking was measured, while the operation after baking was performed. Then, the durability was examined repeatedly.

According to the hot repair material of Comparative Example 2, when the hot repair material was used for one hour of baking, the hot repair material did not remain after 3 charges. Further, when used for baking for 2 hours, the hot repair material was observed to remain even after 6 charges.

On the other hand, the hot repair material of Example 4 was found to remain after 6 charges even though it was baked for 1 hour.

〔The invention's effect〕

As described above, according to the hot repair material of the present invention, by blending the solid pitch in an amount of 15 to 40% by weight, it is possible to obtain sufficient fluidity without impairing the durability and widely cover the damaged portion. be able to. Moreover, powder sulfur is 0.05 to 1.5.
By blending the composition in a weight percentage, it is possible to promote the polymerization of the pitch having fluidity, form a carbon bond structure at an early stage, and increase the strength. As a result, the baking time can be shortened and the repair can be done in a short time, and the durability of the repaired part can be improved, so that the operating rate of the furnace can be increased and the life can be greatly extended. You can get it.

Furthermore, by adding a wetting agent in an amount of 2 to 10% by weight, the kneaded material after kneading is appropriately moistened so that it can be easily agglomerated, and the shape retention after the agglomeration is maintained at a high level. Therefore, it is possible to improve the work efficiency of the charging work into the furnace.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing the results of the spreading test of Examples 1 to 5, Comparative Row 1 and Comparative Example 2, and FIG. 2 is a perspective view showing the shape and dimensions of the sample and crucible used in the spreading test. FIG. 3 is a characteristic diagram showing the results of the strength test of Examples 4, 5 and Comparative Example 2, and FIG. 4 is a perspective view showing the shapes and dimensions of the strength test sample and the casting mold.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masao Oguchi 2 1576, Higashi-oki, Aki, Ako-shi, Hyogo Prefecture 2 Kawasaki Furnace Co., Ltd. (72) Tatsuo Kawakami, 1576 Higashi-oki, Aki, Ako-shi, Hyogo No. 2 in Kawasaki Furnace Co., Ltd. (72) Inventor Tsutomu Yoshida No. 1576, Tohoku, Nakaho, Ako City, Hyogo Prefecture No. 2 in No. 2 Kawasaki Furnace Co., Ltd. (72) Inventor Haruji Okuda Mizushima Kawasaki, Kurashiki, Okayama Prefecture 1 chome (no address) Kawasaki Steel Co., Ltd., Mizushima Steel Works (56) References JP-A-53-75207 (JP, A)

Claims (2)

(57) [Claims] 1. Basic aggregate 60-90% by weight, solid pitch 10-
A hot repair material containing 40% by weight and 0.05 to 1.5% by weight of powdered sulfur. 2. In addition to the above, a wetting agent is used, and as the wetting agent, at least one of liquid phenol resin, polyhydric alcohol such as ethylene glycol, kerosene, heavy oil, anthracene oil, and water is used in a total amount of 2 to 10 wt. %, The hot repair material according to claim 1.