JPS6059184B2 - fireproof material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to bricks for lining various steelmaking furnaces such as converters, electric furnaces, and ladles, ironmaking furnaces such as hot metal furnaces, pig iron mixing cars, and gutters, and their auxiliary equipment; , relates to a fireproof material suitable as a hot repair material.

Hereinafter, a case where the refractory of the present invention is used as a hot repair material will be described as an example.

Traditionally, hot repair of the lining of steelmaking converters, ladles, etc.
This is usually done by spraying with a gun.

In order to improve the compatibility with the lining material during hot heating, the repair material used for this purpose is made of N. O. -SIO, system, MgO
-CaO-based or MgO-based materials have been used, and silicates or phosphates have often been used as binders to promote sintering. However, refractory materials using these binders have insufficient high-temperature strength, and if carbonaceous refractory materials are used for the lining of the target furnace,
The disadvantage was that it did not blend well with the lining, making it useless as a repair material. For this reason, there is a method of adding silicon carbide powder to the aggregate to improve its strength at high temperatures, and a method of adding fine powder of metallic silicon to the aggregate together with carbon to improve the sinterability of the added silicon carbide. A method has been proposed to use it.

However, even with such improvement measures, especially when the lining material is a carbonaceous material, there is still a problem in that adhesion is not sufficient and material loss during spray repair is still large.

The purpose of the present invention is to eliminate the drawbacks of the conventional refractory materials, and by making the refractory aggregate coexist with silicon and aluminum as well as carbonaceous materials, it is possible to prevent hot adhesion to any type of lining. The purpose of the present invention is to provide a refractory material that has good properties, exhibits strength at both low and high temperatures, and has excellent corrosion resistance and abrasion resistance. The silicon metal added to the refractory aggregate is heated and forms β-SiC through a gas phase reaction with the carbon added at the same time to improve the wear resistance of the repair material.

In the present invention, aluminum is added together with silicon, but when added alone, the added aluminum itself does not contribute to strengthening the repair material, but when added together with silicon, it causes sintering with the refractory lining. This was completed based on the knowledge that the bending strength of the repair material could be increased by improving the bending strength of the repair material. The ratio of aluminum to added silicon is silicon/aluminum in a weight ratio of 3 to 10:
It was confirmed that a range of 10 to 3 is necessary from the viewpoints of increasing bulk specific gravity, decreasing apparent porosity, and further improving bending strength.

As the aggregate used in the fireproof material of the present invention, any general fireproof materials such as silica, kaolinite, alumina, magnesia, magdro, dolomite, and silicon carbide can be used.

The repair material usually has a particle size of 107 m or less. As the carbonaceous powder, in addition to coal coke, petroleum pitch coke, anthracite, artificial and natural graphite, carbon black, and mesofus carbon, binders such as high softening point pitch can also be used as carbon sources.
The amount of addition is determined depending on the amount of silicon and aluminum added at the same time. To prepare the refractory material of the present invention for use as a hot repair material, fine carbon powder such as carbon black and fine powders of metallic silicon and aluminum are mixed quantitatively into a refractory aggregate having a particle size of 10Wr1n or less. In this case, the total amount of metallic silicon and aluminum is preferably 10 to 4% by weight based on the total mixture. This is kneaded with a thermosetting resin liquid such as liquid phenol to form a paste, which is used as a spraying material. The present invention has been explained above by citing the characteristics of the material as a hot repair material.Of course, the refractory of the present invention is suitable as a hot repair material, but it can be As a molded refractory brick,
It can also be used in various metallurgical furnaces and other reducing atmosphere industrial furnaces. In addition, in the case of bricks, it is preferable that the total amount of metal silicon and aluminum is 3 to 2% by weight based on the total mixture. Next, details will be explained based on examples of the present invention.

Example 1 Sintered alumina was used as the refractory aggregate, and carbon fine powder and 0.9% Si with a purity of 9% or more were added to the alumina.
2T! r! ! The fireproofing material of the present invention is prepared by adding a mixed powder of metal silicon fine powder having a particle size of t or less and a metal aluminum fine powder having a purity of 0.0747 m or less and having a purity of % by weight or more as A1, and using a thermosetting liquid phenol resin as a binder. Material samples numbers 3 to 14 were created. After molding the refractory material of the present invention, the bulk specific gravity, apparent porosity, and bending strength after reduction firing were measured. As a control, refractory material sample No. 1 without the addition of Si and A1 and refractory material sample No. 2 without the addition of A1.
was made and similar measurements were made. Table 1 shows the composition of the refractory material and the measurement results of its properties. From the above results, it has become clear that the bending strength is increased by adding Si compared to the case of only carbon bond, but the increase in strength becomes remarkable by adding N together with Si.

Example 2 The refractory material of the present invention, Sample No. 5 manufactured in Example 1, was made fluid by adding thermosetting liquid phenolic resin, and the composition was sprayed onto a sliding nozzle plate after casting. A magnification of 165) is shown in the drawing.

The plate is at the bottom of the photo. The sprayed material of the present invention adheres well to the plate. The white part is the Al foil, and the gray part is the matrix in which Al, Si, alumina, and carbon have reacted. The black gray and black parts of the X mark are pores.
The above example shows the use of the present invention in hot spraying.Next, the properties of a molded product of the present invention will be described. Example 3 SiC grains and sintered alumina are used as the refractory aggregate, and the carbon fine powder and Si are 90% or more, 0.2W0F! Add a mixed powder of metal silicon fine particles with a particle size below and metal aluminum fine particles with an A1 of 98% or more and a particle size of 0.07 or less, use a thermosetting liquid phenol resin as a binder, and press this at a molding pressure of 1000 k9/ Pressure molded at d and 1 at 1300°C.
A refractory molded article of the present invention which was subjected to ctf reduction firing was produced, and its bulk specific gravity, apparent porosity, and bending strength were measured.

For comparison, refractory molded samples Nos. 15 and 16 without the addition of Si and N were prepared and the same measurements were performed. The measurement results of its properties are shown in Table 2. Example 4 A refractory molded product was produced in the same manner as in Example 3 using magnesia as the refractory aggregate, and its bulk specific gravity after reduction firing was
Apparent porosity and bending strength were measured.

Its composition and properties are shown in Table 3. Example 5 Table 4 shows the effect of the combined addition of silicon and aluminum when high soft point pitch is used as a carbon source.

Claims (1)

[Claims] 1 Adding silicon and aluminum to a refractory aggregate mixture containing 30% by weight or less of carbon based on the refractory aggregate:
A fireproof material characterized by adding aluminum in a weight ratio of 3 to 10:10 to 3.