JPH08277170A - Monolithic refractory for lining of oven - Google Patents

Abstract

PURPOSE: To obtain a monolithic refractory resistant to the propagation of crack generated by thermal spalling or structural spalling and having excellent peeling resistance. CONSTITUTION: This monolithic refractory for the lining of oven contains 10-30wt.% of crushed refractory granules having particle diameter of 10-30mm and surface-coated with a metal alkoxide solution or a sol solution containing oxide particles dispersed in water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous refractory lining for kiln equipment having excellent durability.

[0002]

2. Description of the Related Art Alumina-silicon carbide-carbonaceous material, lozenge-alumina-silicon carbide-carbonaceous matter, alumina-spinelaceous matter, alumina-silica in order to save labor in the construction of kiln furnace equipment in the steelmaking industry. Various amorphous refractories such as quality have been developed. As a result, the use of irregular refractory materials in place of regular refractory materials is rapidly spreading. When cracks are generated in the structure constructed with the standard refractory by thermal spalling or structural spalling, the cracks that have progressed but stop due to joints do not cause large peeling wear. .

On the other hand, when a kiln-furnace facility is constructed with an irregular-shaped refractory, there is no joint that can be seen when the furnace is constructed with a regular refractory, and the structure becomes an integral structure. When a crack is generated by poling or structural spalling, there is no joint for suppressing the progress of the generated crack, so that the crack propagates and large peeling wear occurs. In order to suppress the development of cracks that lead to such a large amount of peeling wear, it has been practiced to add refractory crushed particles to an amorphous refractory as proposed in, for example, JP-A-5-117049.

[0004]

However, since the refractory crushed particles used in the above-mentioned JP-A-5-117049 have a large particle size of usually 10 to 30 mm, the reactivity is poor and the amorphous fire resistance during use. It is impossible to form a ceramic bond with the fine particles constituting the matrix structure of the product. As a result, the cracks generated and propagated in the irregular shaped refractory, even when hitting the refractory crushed particles, because the ceramic bond is not formed between the refractory crushed particles and the fine particles constituting the matrix structure , Cracks easily bypass refractory crushed grains and propagate. Therefore, the present situation is that the addition of refractory crushed particles to an amorphous refractory does not sufficiently exert the effect of suppressing crack growth and the life is not extended.

Therefore, it is an object of the present invention to provide an amorphous refractory material which is excellent in peel resistance by suppressing the progress of cracks generated by thermal spalling or structural spoke ring.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a metal alkoxide solution or a sol solution in which oxide particles are dispersed in water is surface-coated with a particle size of 10 mm or more and 30 mm or more. It is a refractory lining with an indeterminate shape for kiln furnace equipment, which contains 10 to 30 wt% of the following crushed refractory particles.

The metal alkoxide solution used in the present invention may be any of silicon alkoxide, aluminum alkoxide, titanium alkoxide, magnesium alkoxide, zirconium alkoxide and zircon alkoxide solutions.

The sol solution used in the present invention may be an aqueous solution in which silica, alumina, titania, magnesia, zirconia, and zircon are dispersed as oxide particles. The particle size of the oxide particles is preferably 1 μm or less in order to form a ceramic bond between the refractory crushed particles and the fine particles forming the matrix structure of the amorphous refractory.

As the refractory crushed particles, any of an alumina refractory raw material, an alumina-silica refractory raw material, a spinel refractory raw material and a magnesia refractory raw material can be used.

The amorphous refractory used in the present invention includes:
Alumina-silica, typified by chamotte, loach-zircon, alumina-silicon carbide-carbon, loach-alumina-silicon carbide-carbon, alumina-spinel, alumina-magnesia, Alumina-spinel-magnesia, spinel-magnesia,
Any of magnesia-lime and magnesia-zircon can be used.

The surface coating of the metal alkoxide solution on the refractory crushed particles or the sol solution in which the oxide particles are dispersed in water is performed by impregnating the refractory crushed particles in a bath of the metal alkoxide solution or the sol solution at room temperature, and then 10 in the air
This is possible by drying at a temperature of 0 ° C. or higher.

[0012]

The metal alkoxide solution used in the present invention produces very fine oxide particles by thermal dispersion. Therefore, the refractory pulverized particles surface-coated with the metal alkoxide solution of the present invention are in use, or on the other hand, the refractory pulverized particles surface-coated with a sol solution in which oxide particles (preferably having a particle size of 1 μm or less) are dispersed in water. After drying, the particles form very reactive fine oxide particles on their surface.

As a result, the refractory crushed particles surface-coated with the metal alkoxide solution or the sol solution are, due to the presence of the fine oxide particles on the surface, between the fine particles constituting the matrix structure of the amorphous refractory material, Ceramic bonds can be formed.

Therefore, when the cracks generated and propagated in the irregular shaped refractory hit the refractory crushed particles, a ceramic bond is formed between the refractory crushed particles and the fine particles constituting the matrix structure. Since the cracks cannot easily bypass the refractory crushed grains and propagate, the cracks can be prevented from progressing and large peeling wear can be suppressed.

Refractory crushed particles having a particle size of 10 mm or more and 30 m
The reason why it is m or less is that it is excellent in peeling resistance. This is because if the particle size is less than 10 mm, the peeling resistance is poor, and if the particle size exceeds 30 mm, segregation occurs during kneading, resulting in a coarse structure and poor corrosion resistance and peeling resistance.

The amount of refractory crushed particles added is 10% to 3%.
The reason for setting it to 0% wt is that it is excellent in corrosion resistance and peeling resistance. This is because if the addition amount is less than 10%, the corrosion resistance and peeling resistance are poor, and if the addition amount exceeds 30%, segregation occurs during kneading, resulting in a coarse structure and poor corrosion resistance and peeling resistance.

[0017]

EXAMPLES Examples of the present invention will be shown below. An example is shown in which refractory crushed particles having a particle size of 10 mm or more and 30 mm or less, which are surface-coated with a metal alkoxide solution or a sol solution in which oxide particles are dispersed in water, are added to an alumina-spinel amorphous refractory material. The conventional product is disclosed in Japanese Patent Laid-Open No. 5-11704
It is an alumina-spinel amorphous refractory to which pulverized alumina particles proposed in Japanese Patent No. 9 are added.

[0018]

[Table 1]

[0019]

[Table 2]

The circles in Tables 1 and 2 indicate the particle size of the refractory crushed particles used. Further, Table 1 shows examples of the present invention and Table 2
Shows the test results of the comparative example and the conventional product. In each example, an appropriate amount of construction water was added, vibration casting was performed in the mold, and
After drying at 0 ° C. for 24 hours, a corrosion resistance test and a peeling resistance evaluation test were performed.

The corrosion resistance test was carried out by the rotary erosion method.
The sample shape has a cross section of 50 mm on the top side and 115 m on the bottom side.
It is a trapezoid with a height of 80 mm and a length of 150 mm. Six samples of this shape were concentrically attached to each other and subjected to a corrosion resistance test.

The test was conducted by repeating 5 times the operation of introducing slag after the atmospheric temperature reached 1600 ° C. and discharging the slag after 30 minutes. The molten steel pot slag was used as the slag. The corrosion resistance was measured by measuring the thickness of the maximum erosion site of each sample, and indexed with that of Conventional Product 1 as 100. The higher the index, the worse the corrosion resistance.

The peeling resistance was evaluated by evaluating the degree of cracking that occurs when repeated thermal shock is applied to the amorphous refractory material. In the test, the sample was placed in a furnace with an atmospheric temperature of 1400 ° C, and after 30 minutes, it was taken out of the furnace.
The operation of repeating forced air cooling for 10 minutes was repeated 5 times.

The sample shape is 80 mm × 80 mm × 2
It is a rectangular parallelepiped of 00 mm. The degree of cracks that occurred was evaluated by evaluating the presence or absence of cracks on the cut surface of the sample after the test and the degree thereof. Evaluation of crack initiation is
A: No cracks, B: Small cracks are slightly present, C: Micro cracks are present, D: Small cracks are present, and E: Large cracks are present.

Examples 1 to 5 exhibited excellent peeling resistance as compared with the conventional amorphous refractory material to which the refractory crushed particles were added. On the other hand, in Comparative Example 1, the amount of refractory crushed particles added was 10w.
Since it was less than t%, it was inferior in corrosion resistance and peeling resistance. Comparative Example 2 was inferior in corrosion resistance because the amount of refractory crushed particles added was more than 30 wt%. Comparative Example 3 was inferior in corrosion resistance and peeling resistance because the particle size of the refractory crushed particles was less than 10 mm. Comparative Example 4 was inferior in corrosion resistance because the refractory crushed particles had a particle size of more than 30 mm.

[0026]

The metal alkoxide solution of the present invention, or a sol solution in which oxide particles are dispersed in water, has an irregular shaped refractory to which surface-coated refractory crushed particles are added. Compared to the added amorphous refractory, it shows superior peeling resistance, so by using it as a refractory lining for kiln furnace equipment, it is possible to extend the furnace life and reduce refractory costs. It is effective.

Claims (1)

[Claims] 1. A particle size of 10 which is surface-coated with a metal alkoxide solution or a sol solution in which oxide particles are dispersed in water.
crushed particles of refractory having a size of 30 mm or more and 30 mm or less are 10 wt% to
An amorphous refractory lining for kiln equipment characterized by containing 30 wt%.