JPH06220512A - Method for repairing inner wall of blast furnace - Google Patents

Abstract

PURPOSE:To enable repairing of local damage in the inner wall of a blast furnace by charging metallic balls packing refractory into the blast furnace during operation. CONSTITUTION:In the condition of continuing the blast furnace operation, the metallic balls 4 are charged from a hopper 5 for charging the ball packing the refractory in a local damage direction onto the charged raw material layer on the inner wall of the blast furnace through a raw material charging chute 3. The metallic ball 4 contains the refractory mortar in the inner part and the outer periphery is covered with metal coated layer of Cu or Al, etc. Depending on the position to be repaired (upper part on lower part of furnace) in the inner wall of the blast furnace, the metal having different m.p., (e.g. Al: m.p. 660 deg.C or Cu: m.p. 1083 deg.C) is selectively used and the coating thickness is also adjusted. Of course, the quantity of the monolithic refractory in the inner part is decided according to the damaging degree to be repaired. The charged metallic balls 4 are melted with the furnace heat and dropped along the furnace wall and metal melting is completed near the scheduled position, and the mortar is extracted to complete the repairing.

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 locally worn portion of an inner wall of a blast furnace in the presence of a charging material layer in the furnace without shutting down the blast furnace.

[0002]

2. Description of the Related Art A conventional blast furnace inner wall repair method is as follows:
Typically, after stopping the operation of the blast furnace, boring from the outside toward the worn part of the inner wall of the blast furnace, stopping the boring after reaching the damaged part, and inserting the nozzle into the past boring path. An irregular shaped refractory from an external refractory press-fitting machine is press-fitted into the damaged part through the refractory press-fitting nozzle.

However, shutting down the blast furnace imposes a heavy economic burden, and therefore the above-mentioned repair method has a limitation that it can be performed only in an emergency such as when serious damage is observed. is there. In addition, the inner wall part with built-in staves also has restrictions on the press-fitting place such that boring is impossible, and boring is required every time for press-fitting of irregular shaped refractory. It can be said that it is a means.

Therefore, there is a demand for the development of a technique for repairing a localized damage with a small damage without stopping the blast furnace. Thus, as one of the methods for repairing the damaged portion of the inner wall of the blast furnace without suspending the operation of the blast furnace, as described in Japanese Patent Publication No. 57-14728, the blast furnace is operated at reduced scale to There is a method in which the damaged part is exposed inside, and the arm of the repairing device is inserted from the furnace opening and the amorphous refractory is sprayed toward the damaged part. According to this method, the damaged inner wall can be repaired in a hot state without completely stopping the blast furnace operation. However, the scale reduction operation of the blast furnace is necessary, which is difficult in terms of implementation.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method capable of repairing a local damage on the inner wall of a blast furnace which can be carried out easily and easily without stopping the operation of the blast furnace.

[0006]

In order to solve the above problems of the prior art, the present inventor has found that the top charging raw material layer in the blast furnace tends to descend along the inner wall of the furnace, The rate of descent of the furnace can be roughly estimated, the inner wall of the furnace is constantly inward, that is, the force outward from the center, the material descending along the inner wall of the furnace is pressed against the inner wall, and the irregular refractory is The present invention has been completed based on the knowledge that the adhesiveness to the inner wall is good and the material can be easily pressed into the recess.

Here, the gist of the present invention is to repair the locally damaged portion of the inner wall of the blast furnace without stopping the blast furnace and maintaining the charged raw material layer in the furnace while maintaining the top of the furnace. , For example, charging a metal ball filled with a refractory in a local damage direction from a raw material charging chute, the metal ball is melted while the ball descends along the inner wall of the furnace, and the refractory inside is extracted. This is a method of repairing the inner wall of the blast furnace, which is characterized by repairing a locally damaged portion of the inner wall of the blast furnace.

According to a preferred embodiment of the present invention, refractory-filled metal balls (hereinafter simply referred to as balls) are first charged into an upper bunker in the furnace from, for example, a raw material charging hopper provided at the top of the furnace, and the blast furnace is charged. The material charging chute is fixed to the damage direction on the inner wall, and the balls are charged on the charging material layer in the blast furnace.
After that, the metal ball descends along the inner wall of the blast furnace, melts at the high temperature part, the amorphous refractory inside is pushed out, pressed against the inner wall part, and repairs the local damage formed at that position .

The metal of the balls on the charging raw material layer is
It does not melt until the temperature rises to the melting point, but melts while being dragged by the unloading of the charge. Furthermore, the surface of the inner wall and the surface of the charging raw material layer are not smooth, are notched, and have many irregularities even in the height direction, so that the mortar of the ball tends to adhere. Therefore, the main role of falling of the ball is lubrication due to melting of the metal.

The material of the ball used in the present invention is a repaired part.
Metals with different melting points depending on (upper furnace or lower furnace), for example
Use Al (melting point 660 ℃) and Cu (melting point 1083 ℃) separately and adjust the coating thickness. The material and thickness are set in advance so that the material melts when it reaches the repaired portion. Of course, the amount of amorphous refractory inside can also be determined by the degree of damage to be repaired. The reason why the metals having different melting points (Al, Cu) are selectively used at the repairing site is that the heights of the fall are different, and Al and the like are extracted by the mortar on the inner wall of the furnace upper part, softened and pressed against the inner wall.

[0011]

Next, the operation of the present invention will be described more specifically with reference to the accompanying drawings. FIG. 1 is a schematic explanatory view for explaining an operation example of the in-reactor repair method according to the present invention.
FIG. 3 is a schematic sectional view showing the structure of a metal ball used in the present invention.

In the figure, a blast furnace 1 is provided with an upper bunker 2 at the top, which is connected to a raw material charging chute 3. Particularly, in the case of the blast furnace embodying the present invention, the upper bunker 2 is further provided with a hopper 5 for charging the refractory-filled metal balls, that is, the metal balls 4.

Here, when a portion requiring repair, that is, a damaged portion is found by a furnace observation device such as a furnace wall thermometer during the operation of the blast furnace, first, the direction, the position, and the degree of the damage are determined. Based on the data of 1., the amount of indefinite refractory, the type of metal coating it, and the thickness of the coating layer are first determined, and the metal ball to be used is prepared. On the other hand, the raw material charging chute 3 turns its direction to the direction in which damage is found.

After the preparation is completed in this manner, the metal balls 4 are charged from the hopper 5 for charging the refractory-filled balls provided on the upper portion of the upper bunker 2 while the blast furnace operation is continued, and the raw material is charged. Through the charging chute 3, the metal balls 4 are charged onto the charging raw material layer in the blast furnace toward the inner wall local damage direction.

Metal balls 4 charged on the charging raw material layer
Is to fall along with the raw material in the blast furnace along the inner wall of the blast furnace, and when it reaches the damaged part in the lower part of the furnace, the metal coating layer of the metal balls is melted by high temperature heat and the amorphous refractory inside is extracted and adheres to the inner wall. To repair the damaged area.

As described above, the descending speed of the blast furnace raw material is obtained in advance, and the time required to reach the damaged site can be known.
Therefore, the temperature of the metal ball that has risen by that time is also required. Therefore, it is possible to design that the amorphous refractory is extruded from the inside by melting well at that time.

For example, as shown in FIG. 2, the metal ball 4 has a refractory mortar 7 inside, and the periphery thereof is covered with a metal coating layer 8 such as Cu or Al. In the case of such a metal ball having a diameter of 20 mm provided with an Al coating layer having a thickness of 5 mm, the amount of the amorphous refractory material is 4 cm ³ ,
In the case of a normal blast furnace, it can be assumed from the calculation and empirical fact that it will melt at a position 15 meters below the furnace top.

The mortar-filled metal balls charged on the surface of the raw material layer for the interior of the furnace are placed on the inner wall and a slight gap between the unmelted charge (sinter ore, coke ... High melting point). The charged raw material is softened as it goes downward by the hot air from the lower part of the furnace and forms a reverse V-shaped softening cohesive zone, and is unloaded, and the gap with the inner wall of the furnace is gradually expanded. On the other hand, in the metal ball, the metal part is melted by the furnace heat (charge, hot air, generated gas), the diameter is gradually reduced, and the metal ball descends while expanding the gap with the inner wall of the furnace. This descent is further promoted because the metal ball is a slippery sphere.

That is, the metal balls introduced at the top of the furnace gradually fall in diameter and descend from the upper part of the furnace to the lower part of the furnace along the wall of the furnace. The gap between the inner wall of the furnace and the charged material expands in the upper part of the furnace, but becomes narrower from the time it reaches the lower part of the furnace, so that the metal balls are pressed. At this time, melting of the metal portion is completed, mortar is extracted, and repair is completed.

The metal of the metal ball that has been melted
Since (Al, Cu) is absorbed and floats in the slag as an oxide, there is no problem in blast furnace operation due to this. Next, the operation and effect of the present invention will be described more specifically by way of examples.

[0021]

EXAMPLE In this example, an actual blast furnace having the structure shown in FIG. 1 is used. Metal balls having the structure shown in FIG. 2 (Al is used as the metal)
Using, the repair test of the damaged part was performed without stopping the blast furnace.

Al-coated metal balls (diameter 20 mm, refractory mortar, volume 0.04 m ³ ) were charged into the upper bunker from 20 metal ball charging hoppers, and the raw material charging chute was fixed to the blast furnace inner wall local damage direction, Metal balls were charged on the charging raw material layer in the blast furnace.

The metal balls were designed so that the metal coating melts when they reach a damage site which was previously determined by the furnace wall thermometer to be found 15,000 mm from the furnace top. As a result, the local damage was repaired and the subsequent blast furnace operation continued without any problems.

[0024]

EFFECTS OF THE INVENTION According to the present invention, the blast furnace inner wall can be operated without stopping the blast furnace operation and without reducing the scale even during the operation by a simple means of simply charging the metal balls from the raw material charging hopper. Since the locally damaged portion can be repaired, the practical advantage of the present invention is great.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a blast furnace for carrying out the present invention.

FIG. 2 is a schematic explanatory view of a metal ball used in the present invention.

Claims (1)

[Claims] 1. When repairing a locally damaged portion of the inner wall of a blast furnace, a metal ball filled with a refractory material is charged from the top of the furnace in a locally damaged direction without stopping the blast furnace, and the ball is inserted into the inner wall of the furnace. A method for repairing an inner wall of a blast furnace, which comprises repairing a locally damaged portion of the inner wall of the blast furnace by melting the metal balls in the process of descending along the wall and extracting the refractory inside.