JP2001343192A - Method for executing wet spraying of monolithic refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve adhesiveness between a monolitic refractory 3 for spraying and slag 2 without removing the slag 2 on a surface to be mended, in mending a refractory by spraying the monolitic refractory. SOLUTION: As the refractory material, refractory mortar consisting of minute particles wherein the maximum particle size is 0.5 mm or less and particles having a particle size of 0.075 mm or less occupy 50 percentage by mass or more, is sprayed to the surface to be mended, followed by spraying the monolithic refractory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for wet spraying an amorphous refractory, and more particularly to a method for repairing a lining refractory used for a molten metal container.

[0002]

2. Description of the Related Art In recent years, when a refractory lining a molten metal container is worn to some extent after use, it is necessary to remove pig iron or the like adhering to the refractory in a portion of large wear and to replenish the refractory. It has been generalized. This is because it is expected that merits such as refractory loss due to dismantling even the refractory in a portion with little wear can be reduced, and the number of repair steps can be reduced.

[0003] Spraying is often used for this replenishment repair, but the refractory used for these replenishment is apparently degraded due to peeling due to low adhesion to the work surface. In many cases, it is not possible to obtain a use effect that is commensurate with the thickness of the construction.

[0004] The low adhesiveness is caused by slag adhering to the surface of the object to be processed, and the refractory sprayed has a low adhesiveness to the slag, so that it tends to peel off. Disassembling and removing the attached slag solves the problem, but in reality it is difficult to completely remove the slag because the slag adheres firmly and varies in thickness and unevenness. However, it is difficult to carry out the method because the mechanical shock is easily applied and a crack is easily formed.

[0005] Further, after spraying the sprayed material to a required thickness on the damaged portion to form an underlayer, an anchor is protruded from the underlayer at a required interval by a firing device, and the spraying material is further formed thereon. Spraying water to form an adhesion layer (Japanese Patent Publication No. 60-
No. 51032) and a technique of spraying a surface to be sprayed and roughening the surface each time each refractory layer is applied to form an anchor (Japanese Patent Application Laid-Open No. 10-111082) has been proposed. However, these techniques do not improve the adhesiveness of the surface of the refractory to be applied to the adhered slag layer.

On the other hand, instead of the above measures, recently, in order to increase the adhesiveness of the refractory to be added to the surface of the object to be processed, a technique of forming an adhesive layer in advance on the surface to be processed, and then replenishing the refractory to apply the refractory thereon Has been advocated. For example, an adhesive such as water glass, phosphoric acid, or boric acid is applied in advance. Since the melting softening point of these inorganic substances is as low as 500 ° C. to 600 ° C., adhesion can be exhibited at a temperature of 500 ° C.
However, those inorganic substances have melting points of 800 to 90.
Since it is low at 0 ° C., when the formed adhesive layer reaches a temperature of 900 ° C. or higher, it flows (1200 ° C. in actual results) and disappears,
The coating effect is lost. That is, when the temperature of the adhesive layer, which rises as the residual thickness of the refractory decreases, reaches 1200 ° C., the application effect disappears, and the added refractory peels off early.

Further, a neutral refractory is sprayed on a damaged portion of the lining made of an acidic refractory to form a base relaxation layer,
A technique of spraying basic refractories on it (Japanese Patent Publication No. 60-5)
No. 3835) has also been proposed, but this technique aims at alleviating the difference in thermal expansion, and does not take into consideration the adhesion of the surface of the refractory to be applied to the adhered slag layer.

[0008] As described above, in the repair of refractories by refilling by spraying irregular refractories, at present, the replenished irregular refractories do not last long irrespective of the construction technique employed.

[0009]

SUMMARY OF THE INVENTION In view of the foregoing, an object of the present invention is to provide a method for spraying and repairing slag on a workpiece without removing slag attached to the surface of the workpiece.
An object of the present invention is to provide a spray repairing method with improved adhesion to slag.

[0010]

Means for Solving the Problems In order to achieve the above object, the inventors have made intensive efforts to develop a new spray repair method, and have embodied the results in the present invention.

That is, according to the present invention, when a refractory material obtained by kneading a refractory material with water is pumped by a pump and sprayed onto a repaired surface of a refractory construction body through a nozzle, fine particles of the refractory material are used. And then spraying the refractory mortar obtained by kneading the refractory with water onto the surface to be repaired, and then spraying the irregular refractory. In this case, it is preferable to use a refractory mortar in which the maximum particle size is 0.5 mm or less, and the particles having a particle size of 0.075 mm or less are 50% by mass or more.
Further, when spraying the refractory mortar, it is preferable that the binder or the coagulant or both are mixed and sprayed with the refractory mortar at the nozzle portion. Here, the binder is a material that promotes the bonding with the slag layer, and refers to, for example, an alkali salt such as silicic acid, phosphoric acid, aluminate, or alumina cement. The coagulant has a function of coagulating particles in the refractory mortar, and examples thereof include calcium chloride, potassium chloride, and aluminum sulfate.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a refractory pot or gutter used for holding or distributing molten metal or molten slag is used as an object to be subjected to spray repair. And Since these workpieces are exposed to high temperatures and are in contact with the molten metal and slag, they are mechanically or chemically worn. In order to repair this, first, the molten metal and slag that come into contact with the workpiece are discharged to reveal the surface to be repaired and cooled.

Usually, solidified metal or slag remains on the surface to be repaired. Of these, the solidified metal is removed. The slag may be attached as thick as tens of millimeters or more by cooling at the site where the slag is in contact with the atmosphere during use of the work piece. Thickness. Even if there is no slag or metal adhered or even if slag is adhered, a portion of about 2 to 3 mm or less proceeds to the next spraying step without any problem.

For spraying the amorphous refractory, a usual spraying method can be used. That is, while the amorphous refractory is kneaded in the tank, it is pumped by a pump, and the amorphous refractory is blown from the tip of the nozzle to the repaired surface of the workpiece by high pressure air or the like via a pipe or a hose.

According to the present invention, prior to the spraying of the refractory, the refractory mortar obtained by kneading the refractory material constituting the irregular refractory with water is sprayed onto the surface to be repaired. Features. Thereby, since the fine-grained material adheres to the irregularities or cracks on the surface to be repaired to form a layer, the adhesion strength between the surface to be repaired and the refractory mortar can be extremely increased.

FIG. 1 and FIG. 2 schematically show this.
FIG. 1 is a cross-sectional view showing that a refractory mortar 4 made of a fine refractory material is applied to a surface 6 to be repaired and then an irregular refractory 3 is sprayed thereon, and FIG. FIG. 3 is a cross-sectional view showing a case where a fixed refractory 3 is sprayed. FIG.
Then, the repaired surface 6 of the workpiece 1 covered with the slag 2
Since the fine refractory material 4 adheres densely to the irregularities or cracks of the surface, the repaired surface 6 and the fine refractory when the amorphous refractory 3 is dried and sintered after spraying construction The contact with the refractory mortar 4 made of a material becomes tight, and the adhesive strength can be increased.

On the other hand, when a normal amorphous refractory is directly sprayed on the surface to be repaired, as shown schematically in FIG. 2, the non-fine particles in the irregular refractory and a large diameter which becomes aggregate. The particles 5 contact the surface 6 to be repaired, so that when the particles are dried and sintered, the surface 6 to be repaired and the irregular-shaped refractory 3 are not in smooth contact with each other, resulting in poor adhesive strength.

As shown in FIG. 1, a layer of a refractory mortar 4 made of fine refractory material having a thickness of 2 m is formed on the surface 6 to be repaired.
m, then the refractory mortar 4 previously sprayed is originally identical in composition to the amorphous refractory 3, and the refractory mortar 4 is dried. Since the amorphous refractory 3 is sprayed before sintering, the amorphous refractory layer 3 is very well compatible with the refractory mortar 4, and as a result, the amorphous refractory on the surface 6 to be repaired is very firmly formed. The object 3 can be attached. In other words, a layer having a high adhesive strength can be formed between the repaired surface 6 and the irregular-shaped refractory 3 by the refractory mortar 4 having the same composition as the irregular-shaped refractory 3. Even if adhered, it is possible to carry out strong spray repair of irregular-shaped refractories.

Originally, when replenishment is performed by spraying and repairing the refractory lining (workpiece) of a molten metal container, the inner surface of a pressure feeder or a pressure feed pipe is wetted in advance using a mortar having the same component as the sprayed material. Is usually the case. This is to improve the lubricity of the inner surface of the pressure-feeding device and the pressure-feeding pipe at the time of repair, and to prevent the spraying material from being clogged due to the absorption of moisture from the spraying material into these inner surfaces. Usually, these mortar spraying materials have a high porosity due to a small amount of coarse particles, and have been discarded without being used for forming an amorphous refractory layer. According to the present invention, the refractory mortar used only to wet the inner surface of the spraying material pumping device or the pumping pipe is replaced between the slag layer adhering to the surface of the refractory which is the work piece and the replenishment work body. It was used as an intermediate layer to be formed on the refractory surface of the work piece. Therefore, it has become possible to effectively use a conventionally discarded material as an adhesive layer. Since this refractory mortar has a smaller particle size than the irregular refractory to be refilled, it easily penetrates into the uneven portion of the slag layer, adheres tightly, and has good compatibility with the refractory to be replenished. As a result, the adhesion between the refractory to be added and the object to be processed has been remarkably improved.

The refractory mortar used in the present invention uses fine particles of a refractory material. It is most preferable to use those obtained by removing coarse-grained components from amorphous refractories used for spray repair, but if they have the same composition as amorphous refractories used for spray repair, for example, refractories It is also possible to apply a refractory mortar that is usually used as a joint material of the steel. The refractory mortar of the present invention has a maximum particle size of 0.5 for the purpose of improving the adhesion to the slag layer.
mm or less, and the ratio of particles having a particle size of 0.075 mm or less is preferably 50% by mass or more. When the maximum particle size exceeds 0.5 mm, it becomes easy to hinder the pressure feeding of the material, and the slag layer is less likely to bite into the uneven portions, so that the effect as an intermediate adhesive layer is reduced. Particle size 0.07
If the proportion of the particles having a size of 5 mm or less is less than 50% by mass, the mortar becomes less compatible with the coarse particles, and the possibility of material separation during pumping appears.

In the spraying of the refractory mortar, it is desirable to add a binder for the purpose of further improving the adhesion to the slag layer and the sprayed irregular refractory layer to be sprayed thereafter. As the binder, an alkali salt such as silicic acid, phosphoric acid, or aluminate, which is easily bonded to the slag, alumina cement, or the like is preferable in consideration of the adhesiveness to the slag layer. Although these binders may be used in the form of an aqueous solution, it is desirable to use a binder that undergoes a hydration reaction, such as alumina cement, in the form of a powder. These binders may be mixed with refractory mortar and pumped and sprayed.However, in order to avoid clogging of the piping due to hardened coagulated material in the pumping pipe when a pumping trouble occurs, it is mixed in the spray nozzle. It is better to do.

It is desirable that the spraying layer of the refractory mortar is sprayed on the surface of the slag layer with a thickness of 2 mm or more. 2m thick
If it is less than m, sufficient adhesive strength cannot be obtained.

[0023]

EXAMPLE An irregular refractory comprising 80 parts by mass of silicon carbide and 20 parts by mass of alumina was lined on a slag line of a blast furnace main gutter. After tapping, the minimum thickness of this refractory is 200
When the diameter reached mm, the pig iron solidified in the gutter was removed, and repair was performed by refilling by spraying an amorphous refractory. At that time, the thickness of the refractory to be added was 250 mm. In addition, when adding the refractory, slag adhering to the surface of the existing refractory is not removed, and a refractory mortar consisting of fine powder of 0.5 mm or less of the same component as the refractory to be added is preliminarily formed with a thickness of about 5 mm. Sprayed construction. The spraying of the refractory mortar and the subsequent replenishment of the amorphous refractory are all performed in cold (30
C). Furthermore, in order to confirm the effect of the present invention, a case where the refractory mortar was not sprayed and performed was performed as a comparative example. Tables 1 and 2 show these materials and the results of spraying.

[0024]

[Table 1]

[0025]

[Table 2]

From the results shown in Table 2, it is clear that, when the refractory mortar layer according to the present invention is sprayed and added, the repair layer does not peel off during operation, and the wear rate of the refractory decreases. is there.

[0027]

As described above, according to the present invention, even if the slag adheres to the existing refractory, a separately effective adhesive layer is provided between the slag surface and the reshaped refractory added. Can be formed, a strong repair layer can be easily formed, and the added irregular-shaped refractory does not peel off at an early stage, and the durability of the repaired refractory is improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a surface to be repaired in an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a surface to be repaired in a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 work piece 2 slag 3 irregular refractory (repair layer) 4 refractory mortar (fine refractory material) 5 large particles 6 repair surface

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Etsuro Udagawa 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside the Kawasaki Steel Research Institute Co., Ltd. No.2 Kawasaki Furnace Materials Co., Ltd. F-term (reference) 4K015 EC08 4K051 AA01 BB03 BB08 LA02 LA11

Claims (3)

[Claims] 1. A refractory material obtained by kneading refractory material with water is pumped by a pump, and the fine particles of the refractory material are kneaded with water when the refractory material is blown onto a repaired surface of a refractory construction body through a nozzle. Spraying the resulting refractory mortar onto the surface to be repaired, and then spraying the irregular refractory on the surface to be repaired. 2. The fine particles have a maximum particle size of 0.5 mm or less,
The method of claim 1, wherein the particles having a particle size of 0.075 mm or less are 50% by mass or more. 3. When spraying the refractory mortar,
3. The method of claim 1, wherein a binder and / or a coagulant are mixed with the refractory mortar and sprayed at the nozzle portion.