JPH09255414A - Alumina-silicon carbide-carbon brick for lining molten metal vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject brick improved in oxidation resistance and durability by using a specific modified phenolic resin as a binder. SOLUTION: This alumina-silicon carbide-carbon brick is obtained by using 0.5-10wt.%, based on the whole feedstock, of a boron-modified phenolic resin 10-50wt.% in boron content as a binder through kneading, molding and drying process. The boron-modified phenolic resin can be used singly as a binder in the form of either liquid or powder; however, being pref. used in combination with a conventional phenolic resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in the material of a refractory brick for lining a molten metal container.

[0002]

2. Description of the Related Art As a refractory brick for lining a molten metal container, a brick such as a zircon-based, a loastone-based, or an alumina-based brick has been conventionally used.・ Spoll resistance has come to be required. In order to meet these demands, carbon-containing bricks such as magnesia-carbonaceous material, alumina-magnesia-carbonaceous material, and alumina-silicon carbide-carbonaceous material have been widely used.

By adding carbon to alumina bricks, the bricks have excellent properties such as an increase in the thermal conductivity of the bricks, an improvement in the heat resistant spalling, and an inhibition of the penetration of slag to improve the structural spalling resistance. Granted.

[0004]

Although carbon-containing bricks exhibit excellent properties in a reducing atmosphere, carbon is oxidized and disappears in an oxidizing atmosphere, resulting in severe wear and wear due to weakening of the structure. Solve this problem, A
It is considered that the improvement of oxidation resistance is an effective means for increasing the durability of SC quality bricks. The present invention aims to increase the durability of ASC bricks by improving the oxidation resistance, which is considered to be an effective means.

[0005]

In order to improve the oxidation resistance of ASC bricks, the present invention uses a boron-modified phenolic resin having a higher oxidation resistance than conventional phenolic resins such as novolac and resole. , High durability A
This is a developed SC brick. Traditionally, ASC bricks have been manufactured using novolac or resol type phenolic resins as binders. It is known that these phenolic resins are carbonized by heat treatment such as baking in a dry or reducing atmosphere, and about 50% of them remain in the brick structure to form carbon bonds. However, it is considered that carbon derived from these binders is very unstable and is preferentially oxidized before other carbon species, leading to weakening of the structure.

[0006]

FIG. 1 shows DTG curves of ordinary novolac resin and boron-modified phenolic resin.

As shown in FIG. 1, it is considered that the boron-modified resin has an effect of suppressing the oxidation in the temperature range of 600 to 800 ° C. as compared with the normal novolac resin. The boron-modified phenolic resin can be used either as a liquid or a powder, but the powder is easier to obtain due to the current resin manufacturing technology.
The addition amount is set to 0.5 to 10% by weight because the effect cannot be sufficiently obtained when it is 0.5% by weight or less, and there is no merit in terms of cost and molding when it is 10% by weight or more. is there.

The boron-modified phenol resin may be used alone as a binder, but it is desirable to use it in combination with an ordinary phenol resin in consideration of cost and moldability. Alumina, silicon carbide, magnesia, carbon and additives are blended using the above resins, and are used in combination with pitch, tar, organic resin such as phenol resin, binder such as pulp waste liquid, etc. in a wet pan or mixer. Mix and knead. After press molding with a friction press or hydraulic press, etc., 30 to 500
It is used after curing the binder in the range of ℃ and removing volatile components.

The effects of addition will be described below with reference to examples.

[0009]

【Example】

[Table 1] The raw materials were mixed in the ratio shown in and kneaded in a wet pan.
Then, it was pressure-molded by a friction press and dried at 180 ° C. to obtain an ASC quality brick. The physical properties and test results of the obtained refractory brick

It is also shown in [Table 1]. Physical property values were measured according to JIS. The oxidation resistance was evaluated by holding a sample of 40 mm × 40 mm × 40 mm at 800 ° C. in an electric furnace in an oxidizing atmosphere for 5 hours and measuring the thickness of the oxidized layer after cutting.

[0010]

[Table 1]

As shown in the above table test, the use of the boron-modified phenolic resin as the binder improved the oxidation resistance. No deterioration in strength was observed.

[0012]

EFFECTS OF THE INVENTION On the basis of these results, an actual machine test was carried out using a No. 3 compounding material as a base material on a 250 ton mixed pig car, and as a result, the service life could be improved by 3 to 8%. . As described above, by using the boron-modified phenol resin, the oxidation resistance can be improved and the durability can be improved.

[Brief description of drawings]

FIG. 1 is a chart showing DTG curves of a normal norovolak resin and a boron-modified phenol resin.

Continued Front Page (72) Inventor Hirokatsu Hattan 8-78-401 Wakinoshima-cho, Tajimi-shi, Gifu

Claims (1)

[Claims] 1. In alumina-silicon carbide-carbonaceous brick (hereinafter referred to as ASC brick), 0.5 to 10% by weight of boron-modified phenolic resin having a B content of 10 to 50% by weight is used as a binder. Kneading → molding →
Alumina for lining a molten metal container characterized by having high oxidation resistance obtained by a drying step-silicon carbide-
Carbon brick.