JPH08217553A - Method for lining work with monolithic refractory - Google Patents

Abstract

PURPOSE: To improve the applicability, corrosion resistance, etc., at the time of lining a furnace with a monolithic refractory using the crushed and even- grained spent refractory as a coarse aggregate by previously coating the surface of the coarse aggregate with a high molecular compd., pitch, etc. CONSTITUTION: The coarse aggregate having 10-30mm size and selected from among alumina-silica, alumina-silicon carbide-carbon and alumina-magnesia materials is prepared. The surface of the aggregate is previously coated with PE resin, one kind among high molecular compds. such as silicone rubber and titanium alkoxide and pitch. The surface-coated coarse aggregate, thin aggregate (e.g. alumina) having <=5mm size and binder (e.g. portland cement) are mixed. The obtained monolithic refractory is kneaded with water and used to line a furnace. Consequently, even if the crushed and even-grained material of the spent refractory which has been used once, fined, solidified and made porous is uses as the raw material for a coarse aggregate, the durability is not lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for lining an irregular refractory material.

[0002]

2. Description of the Related Art Alumina-silicon carbide-carbonaceous material, aluminite-alumina-silicon carbide-carbonaceous material, alumina-spinelaceous material, alumina-silicaaceous material in order to save labor in the construction of kiln furnace equipment in the steelmaking industry. Various amorphous refractories have been developed. As a result, the use of irregular refractory materials in place of regular refractory materials is rapidly spreading. Furthermore, recently, in order to reduce the unit price of refractory, for example, Japanese Patent Laid-Open No.
As proposed in Japanese Patent Laid-Open No. 2119853, a refractory once used as a lining refractory of a molten metal container is crushed and used again as an aggregate of an irregular refractory.

[0003]

However, once the amorphous refractory material is used as the lining refractory material of the molten metal container, it is baked and solidified and becomes porous. This porous refractory is crushed and sized, and it is used as coarse aggregate.The irregular refractory absorbs the water added during the construction work, so that the irregular refractory has non-uniform water content. There is a problem in that the distribution occurs, a uniform structure cannot be obtained, and the structure becomes rough, so that the corrosion resistance and the heat-resistant spalling resistance are deteriorated.

Here, in the present invention, when the crushed refractory is used as a raw material for coarse aggregate of an irregular shaped refractory, the crushed refractory as a raw material for coarse aggregate does not absorb moisture during the construction work. It is an object to provide an amorphous refractory that develops a uniform structure.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and uses an amorphous refractory made of coarse aggregate of 30 mm to 10 mm, fine aggregate of 5 mm or less, and a binder as water. At the time of mixing and lining in a kiln, the coarse aggregate of the amorphous refractory material is surface-coated with one of a polymer compound and pitch in advance, and then mixed and applied.

Examples of the coarse bone refractory used in the present invention include alumina-silica, lozenge-zircon, alumina-silicon carbide-carbonaceous, lozenge-alumina-carbonized, typified by lozenges and chamotte. Silicon-carbon, alumina-spinel, alumina-magnesia, alumina-spinel-magnesia, spinel-magnesia,
Either magnesia-lime or magnesia-zircon can be used.

As the polymer compound used in the present invention,
Polyethylene resin, polyurethane resin, alkyd resin, phenol resin, epoxy resin, urea resin, melamine resin, methacrylic resin, fluororesin, silicone resin, silicone oil, silicone rubber, silicone alkoxide, aluminum alkoxide, titanium alkoxide, magnesium alkoxide, zirconium alkoxide. , Zircon alkoxide can be used.

When the surface of a coarse bone refractory is coated with a polymer compound, the polymer compound bath heated to a predetermined temperature is used for 30 m.
It suffices to immerse a coarse bone refractory material of m to 10 mm to impregnate it with a polymer compound of the coarse bone refractory material, and then dry it in air or a reducing atmosphere at a temperature of 100 ° C. or higher.

The pitch used in the present invention may be any of coal tar pitch, pitch and mesophase pitch.

When coating the surface of the coarse bone refractory with pitch, the coarse bone refractory of 30 mm to 10 mm is immersed in a pitch bath heated to a temperature of 100 ° C. or higher to form the coarse bone refractory. The pitch may be impregnated and then dried in air.

The mixing ratio of the coarse bone refractory to the amorphous refractory varies depending on the composition of the irregular refractory to be mixed, but is 30 wt% at most.

Further, as the binder, cement such as Portland cement and blast furnace cement can be used.

[0013]

[Function] As a result of various experiments and examinations conducted by the present inventors,
When using a porous refractory once used as a fine bone refractory of 5 mm or less, it takes a short time from when the fine bone refractory starts to absorb the water added during construction However, if the kneading is performed while supplementing and adding water, the above problem (uneven distribution of water) does not occur. However, when the coarse bone refractory has a particle size of 10 mm or more, it takes a long time until the coarse bone refractory finishes absorbing water, and during that time, when the water is added and mixed while mixing, the entire amorphous refractory solidifies. Since the workability deteriorates,
It has been found that the above problems occur because the mixing cannot be performed while supplementing and adding water sufficiently.

Therefore, the surface of the coarse bone refractory material of 30 mm to 10 mm which has been made porous by baking and solidification by a polymer compound or pitch is coated with an impermeable membrane capable of preventing permeation of water. The formation prevents the coarse bone refractory from absorbing water. as a result,
When a refractory that has been surface-coated with a polymer compound or pitch and used once is reused as a coarse bone material of an irregularly shaped refractory, water added during construction work will not be absorbed by the coarse bone material, Since the added water is uniformly distributed in the irregular-shaped refractory and is supplied with the water without being mixed while replenishing the time, a uniform structure can be obtained, thereby improving the durability.

Further, if the grain size of the coarse bone material of the irregular refractory material exceeds 30 mm, segregation occurs during mixing, resulting in a coarse structure, and the heat-resistant spalling property sharply decreases.

[0016]

EXAMPLES Examples of the present invention will be shown below.

[Example 1] 30 mm to 10 mm of an indefinite refractory for disposal made by burning and solidifying an alumina-silica material which is an indefinite refractory lining of a tundish proposed in Japanese Patent Laid-Open No. 63-291879 using an actual machine After pulverizing and sizing, the surface was coated with a polymer compound, which was mixed as a coarse bone material of an unused alumina-silica irregular shaped refractory (5 mm or less), and an appropriate amount of working water was added to this. Table 1 shows an example of the mixing.

[0018]

[Table 1]

The circles in Table 1 indicate the grain size of the used amorphous refractory for disposal. The conventional product is Japanese Patent Laid-Open No. 63-29.
It is an alumina-silica amorphous refractory material proposed in Japanese Patent No. 1879. Table 1 also shows the test results of the examples of the present invention, comparative examples, and conventional products. In each example, the appropriate amount of construction water was added, vibration casting was performed in a mold, and the temperature was 200 ° C.
After drying for 24 hours, a corrosion resistance test and a heat spalling 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 performed by repeating 5 times the operation of introducing the 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. For corrosion resistance, measure the thickness of the maximum melting point of each sample,
It was displayed as an index as 00. The larger the index, the poorer the corrosion resistance.

The heat-resistant spalling evaluation test was carried out by inserting the sample into a furnace having an atmospheric temperature of 1400 ° C., taking it out of the furnace after 30 minutes, and repeating forced air cooling for 10 minutes five times. The sample shape is a rectangular parallelepiped measuring 80 mm × 80 mm × 200 mm.
The thermal spalling resistance was expressed as an index by measuring the rate of decrease in elastic modulus of each sample before and after the test and setting that of Conventional Product 1 as 100. The higher the index, the lower the heat-resistant spalling property.

In Examples 1 to 5, the corrosion resistance and the heat-resistant spalling resistance are not deteriorated even when compared with the conventional alumina-silica amorphous irregular refractory. On the other hand, in Comparative Example 1, the waste amorphous refractory had a particle size of more than 30 mm, and thus the heat-resistant spalling resistance was inferior. In Comparative Example 2, the crushed discard amorphous refractory was not surface-coated, so that the corrosion resistance was high. And was inferior in heat resistant spalling property.

[Example 2] Amorphous refractory for disposal, which is formed by firing and solidifying alumina-spinel material, which is an amorphous refractory lining of a molten steel refining vessel proposed in JP-A-1-87577, by using an actual machine After crushing to 10 mm, the pitch was surface-coated and mixed as a coarse bone material of an unused alumina-spinel amorphous refractory (5 mm or less),
Further, Table 2 shows an example in which an appropriate amount of water was added and mixed.

[0024]

[Table 2]

The circles in Table 2 show the particle size of the used refractories for disposal. The conventional product is disclosed in JP-A-18757.
It is an alumina-spinel amorphous amorphous refractory proposed in Japanese Patent Publication No. Table 2 also shows the test results of the inventive examples, comparative examples, and conventional products. In each example, an appropriate amount of construction water was added, vibration casting was performed in a mold, and after drying at 200 ° C. for 24 hours, a corrosion resistance test and a heat spalling evaluation test were performed. However, the corrosion resistance test and the heat spalling evaluation test were performed in the same manner as in Example 1.

Inventive Examples 1 to 6 are conventional alumina products.
Corrosion resistance and heat-resistant spalling resistance are not deteriorated even when compared with spinel-type amorphous refractories. On the other hand, Comparative Example 1 was inferior in heat-resistant spalling property because the grain size of the refractory material for disposal was more than 30 mm. Comparative Example 2 was inferior in corrosion resistance and heat-resistant spalling resistance because the ground amorphous refractory material for crushing was not surface-coated.

[0027]

INDUSTRIAL APPLICABILITY According to the present invention, even if a refractory for disposal of any component (a porous material which has been used once and solidified by firing) is used as a coarse bone material of an unused (new) amorphous refractory material. Since it was found that no deterioration in durability was observed, the use of this atypical refractory for disposal as a coarse bone material for atypical refractory has the effect of reducing the raw material unit price of the furnace material. It is a thing.

Claims (1)

[Claims] 1. When a non-standard refractory material consisting of coarse aggregate of 30 mm to 10 mm, fine aggregate of 5 mm or less and a binder is mixed with water and lined in a kiln, the coarse refractory material is A method of lining an amorphous refractory material, which comprises coating an aggregate with a surface of one of a polymer compound and a pitch in advance and then mixing and applying the mixture.