JP2000205761A - Repair of lining of refractory material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform the hydration prevention and the repair work of a lining by applying a liquid silicone on the surface of the lining after a usage of a molten metal container wherein the lining of a basic refractory material is provided, and in addition, covering the top of the coating with a water-impermeable sheet, and then, performing the adding application of an irregular refractory material in which an application water is added. SOLUTION: After a usage of a molten metal container, a liquid silicone 2 is applied on the lining 1 which has been worn, and in addition, after the coating is covered with a water-impermeable sheet 3, the adding application of an irregular refractory material as a repair material 4, is performed. In this case, the basic refractory material of the lining is a material wherein magnesia, dolomite or calcia is blended in an aggregate. Also, the liquid silicone is, e.g. a silicane oil, or a silicone resin. In addition, the material of the sheet needs to be water-impermeable, and is, e.g. a synthetic resin sheet such as nylon, or a metal foil or the like. Then, the material of the irregular refractory material as the repair material, is, e.g. an alumina material, an alumina-silica material, a magnesium material, and a dolomite material or the like.

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 refractory lining by adding a refractory to the refractory.

[0002]

2. Description of the Related Art The lining of a molten metal container or a molten metal processing apparatus such as a ladle, a tundish, a vacuum degassing furnace, etc. used in the steelmaking industry is subject to a replenishment construction using an amorphous refractory in order to extend its life. Repairs have been made. For example, as disclosed in JP-A-4-110594.

[0003]

[0005] Basic refractories have become the mainstream material for the lining of molten steel containers or molten steel processing equipment because of their excellent resistance to molten steel. However, when the lining made of a basic refractory is added to an irregular refractory and repaired by construction, there is a problem that the lining deteriorates due to contact with the steam of the amorphous refractory during drying.

That is, basic refractories have an aggregate component of M
Since gO or CaO is the main material, these components hydrate [Mg (OH) 2 or Ca (OH) 2].
It becomes 2. ], The volume expansion accompanying the hydration weakens the refractory structure.

As a method of solving this problem, it is conceivable to block the lining and the repair material with a water-impermeable sheet such as a synthetic resin sheet. However, when constructing the refractory as a repair material, it is inevitable that the sheet will be damaged due to contact with the aggregates in the refractory, etc. Poor sum prevention effect.

[0006] With a sheet material having sufficient strength not to form a through hole, the through hole does not occur, but
It is difficult to adhere to the lining surface of the irregularities after the erosion to be repaired, and unnecessary voids are generated between the repaired surface and the indefinite refractory, thereby reducing the repairing effect. Further, a sheet material having sufficient strength has a problem in handling, such as being heavy and not easily processed.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problem in the lining repair by relining construction using an amorphous refractory, and is directed to a molten metal container provided with a basic refractory lining. After use, liquid silicone is applied to the surface of the lining, and the surface of the lining is further covered with a water-impermeable sheet.

[0008] In the present invention, firstly, liquid silicone is applied to the surface of the lining after use to cut off the water vapor from the working water of the irregular-shaped refractory to be added and built, thereby preventing hydration of the lining.

Liquid silicone is superior in water repellency and heat resistance as compared with ordinary paints and the like, so that it exerts the effect of preventing hydration even under heating during drying. Further, since it is a liquid, it penetrates into the surface of the refractory structure of the lining, and the hydration resistance is not impaired due to scratches as in the case of using a sheet.

However, the liquid silicone has a high volatility of the solvent, and therefore, after application, the viscosity increases quickly with the volatilization of the solvent and does not reach the depth of the refractory lining. Therefore, the effect of hydration resistance is also limited to the surface portion of the refractory structure.

In the present invention, after the liquid silicone is applied to the surface of the lining, it is further covered with a water-impermeable sheet. The water-impermeable sheet prevents evaporation of the solvent from the lining surface and prevents the viscosity of the liquid silicone from increasing. As a result, the liquid silicone penetrates deep into the refractory structure, and the hydration resistance effect of the silicone can be imparted to the deep portion of the lining.

As described above, in the present invention, the combination of the application of the liquid silicone and the covering with the sheet makes prevention of hydration of the lining to be repaired more effective. as a result,
The effect of repairing the lining can be significantly improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the schematic diagram of FIG. FIG. 1 is a part of a cross section of a side wall of a molten metal container. After using the molten metal container, apply the liquid silicone (2) to the worn lining (1), cover it with a sheet (3), and remove the irregular refractory as a repair material (4). Add and construct.

[0014] Although not shown in the figure, the repair (4) is usually performed by casting using a core.
After construction, the core is removed. A permanent lining or a heat insulating material may be interposed between the lining and the steel (5). In the case where the addition by the refractory is performed by the spraying method, the core is not used.

[0015] The basic refractory lining to be repaired is
It is a material in which magnesia, dolomite or calcia is blended in part or all of the aggregate. Specific examples include magnesia, dolomite, magnesia-dolomite,
Fixed or irregular shaped refractories such as magnesia-carbon, alumina-magnesia, alumina-dolomite, alumina-magnesia-carbon, magnesia-chromium and the like can be mentioned. In addition, each raw material of magnesia, dolomite, and calcia mentioned here includes both natural products and synthetic products.

A specific example of the liquid silicone is a silicone oil or a silicone resin. Its viscosity is 30 ° C
Is preferably 70 cps or less, and more preferably 5 to 50 cps. If the viscosity is too high, it is difficult to penetrate into the refractory structure of the lining, and the effect of preventing hydration is reduced. On the other hand, if the viscosity is too low, it will flow down from the lining surface, and the amount of the silicone component applied will decrease, resulting in poor hydration preventing effect.

Since the silicone oil is in a liquid state, one having an arbitrary viscosity is selected and used. Silicone resin is solid, for example, toluene, xylene,
It is adjusted to a liquid by adding an oily solvent such as mineral spirit or kerosene before use. The viscosity can be adjusted by adjusting the amount of the solvent added.

The effect of preventing hydration is better with silicone resin than with silicone oil. This is thought to be because silicone oil is a linear organopolysiloxane with a low degree of polymerization, while silicone resin has a higher degree of polymerization and a three-dimensional network structure than silicone oil, and condenses when heated. Can be

The liquid silicone is applied by any method such as spraying, brush coating, roller coating and the like. From the viewpoint of work efficiency, application by spraying is particularly preferable.

The material of the sheet needs to be water-impermeable in order to block moisture. The thickness is preferably from 0.1 to 1 mm. Specific examples of the material include a synthetic resin sheet such as vinyl chloride, polyethylene, polypropylene, and nylon, and a metal foil. Metal plates, wood plates and the like are not preferable because they cannot adhere to the uneven surface of the lining after use.

The sheet is attached to the lining with an adhesive, a pin, or the like. The adhesive may be applied to the entire surface of the sheet or the surface to be repaired, or at an appropriate interval.

The material for the refractory of irregular shape as the repairing material is not particularly limited.
Siliceous, magnesia, dolomite, spinel,
Alumina-spinel, alumina-magnesia, alumina-spinel-magnesia and the like.

An irregular-shaped refractory as a repair material is added with an appropriate amount of water in accordance with a construction method or the like, kneaded, and then added to construct. Although not shown in the drawing, a core frame is used for casting and a spray gun is used for spraying.

As a lining structure, a two-layer structure including a wear lining and a permanent lining provided on the back surface thereof is known. In repairing after use in this two-layer structure, there is a method of removing the entire wear lining of the eroded part, leaving the permanent lining, and then adding the part corresponding to the wear lining with irregular shaped refractory material . The present invention can be applied to such a repair method.

Specifically, after the permanent lining is left and the entire wear lining of the eroded portion is removed, liquid silicone is applied to the permanent lining, covered with a water-impermeable sheet, and then formed of a refractory material. And rebuild.

In the present invention, the irregular-shaped refractory after the refilling operation is dried by heating in a usual manner. For heat drying,
For example, there are gas burner heating, introduction of hot air, microwave heating, or a combination thereof.

[0027]

EXAMPLES Examples of the present invention and comparative examples are shown below.
Each example is intended for repair of a lower tank of an RH-type vacuum degassing apparatus lined with magnesia-chromium ore fired brick. The extension was performed by a casting method using a core. Also. Alumina amorphous refractory was used as the repair material.

Example 1: A liquid silicone resin (solvent: an aromatic hydrocarbon based on xylene) was applied to the lining after use by spraying, and then coated with a vinyl chloride sheet having a thickness of about 0.3 mm. The refractory was covered with an amorphous refractory having a thickness of about 200 to 230 mm. After the construction was aged for 24 hours, the core was removed and the upper opening of the lower tank was covered, followed by heating and drying with a gas burner.

Example 2: After applying silicone oil to the lining after use by spraying, it is covered with an aluminum foil having a thickness of about 0.1 mm, and an irregular refractory having a thickness of about 20 mm is further placed thereon.
After adding 0 to 230 mm, curing and heating and drying were performed in the same manner as in Example 1.

Comparative Example 1: A lining after use having a thickness of about 0.3 m
m, covered with a vinyl chloride sheet, and then refilled in the same manner as in Example 1 for construction, curing, and heat drying.

Comparative Example 2: A liquid silicone resin (solvent: an aromatic hydrocarbon based on xylene) was applied to a used lining, and was added, covered, cured and dried by heating without covering with a sheet. .

Comparative Example 3: The lining after use was refilled, cured and heated and dried without applying liquid silicone and covering with a sheet.

With respect to the repair method according to each example, the lining resistance and the durability of the lining after the repair were tested, and the results are shown in Table 1. The test method is as follows.

Hydration resistance: After drying by heating, the state of crack formation in the refractory lining was observed and evaluated based on the degree of cracking.

Durability: Evaluation was made based on the number of usable charges of the entire lining after repair including the lining and the repair material.

In the repair according to the embodiment of the present invention, the occurrence of cracks in the lining after heating and drying is small. As a result, it also has an excellent effect on durability.

On the other hand, the heat-dried lining repaired in Comparative Example 1 has large cracks due to volume expansion due to the hydration reaction and is inferior in durability. The lining repaired in Comparative Example 2 is relatively limited in the effect of preventing hydration on the surface, has large cracks as a whole, and has insufficient durability. The hydration resistance of Comparative Example 3 was further inferior, and cracking was remarkable, so that the durability test was not performed.

[0038]

[Table 1]

[0039]

The present invention can prevent hydration deterioration of the lining and remarkably improve the repair effect thereof in the rehabilitation work on the lining of the basic refractory. For the lining of kilns, repair technology using irregular shaped refractories will become more and more important in the future due to the demand for reduction of the basic unit of refractories. The present invention has a high industrial value as one of the repair techniques to meet the demand.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

[Explanation of symbols]

 1 Lining 2 Liquid silicone 3 Sheet 4 Repair material 5 Iron skin

Claims (3)

[Claims] (1) After using a lining made of a basic refractory, apply a liquid silicone to the surface of the lining, cover the surface with a water-impermeable sheet, and then use an irregular-shaped refractory to which construction water is added. Repair method for refractory lining to be added. 2. The method for repairing a refractory lining according to claim 1, wherein the liquid silicone is a liquid silicone resin. 3. The method for repairing a refractory lining according to claim 1, wherein the water-impermeable sheet is a synthetic resin sheet or a metal foil.