JP2989118B2 - Silicon iron nitride - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an iron content of 4 to 8 % by weight.
Related to silicon iron nitride.

[0002]

2. Description of the Related Art Conventionally, as a fixed refractory such as a brick, a mud material for closing a blast furnace taphole, a tapping gutter material, etc., silicon nitride for imparting corrosion resistance and refractory strength ( A mixture with an aggregate for providing hot strength) or the like is used. As the aggregate, oxide powders such as silica and alumina, and non-oxide powders such as carbon and silicon carbide are used.

However, the iron content of conventional silicon iron nitride is as high as 15% by weight or more, so that iron existing in the refractory becomes a liquid phase in a high temperature range of 1400 ° C. or more, which weakens the structure, and thus the corrosion resistance to slag is reduced. There was a problem of lowering.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a silicon iron nitride capable of producing a refractory having improved corrosion resistance to slag in a high temperature range and fire resistance. That is.

[0005]

[Means for Solving the Problems]

That is, the present invention is a silicon iron nitride having an iron content of 4 to 8 % by weight.

Hereinafter, the present invention will be described in more detail.

[0008] Iron in silicon iron nitride promotes a reaction when silicon nitride, aggregate, silicon nitride and aggregate react at high temperature to produce silicon carbide, aluminum nitride and the like in a matrix to densify the structure. Functions as an agent. However, in these reactions, iron is involved in the reaction while being recycled to some extent, so if there is a large amount of iron, the amount of gas such as nitrogen and carbon monoxide, which originally remain and reacts with silicon nitride, which is involved in matrix reinforcement, is generated. Therefore, pores increase in the sintered body and the fire resistance decreases. Further, excess iron remains as a liquid phase in a high temperature region of 1400 ° C. or more, which causes a reduction in fire resistance and corrosion resistance.

In view of the above, in the present invention, the iron content of silicon silicon nitride is limited to 4 to 8 % by weight.
If the iron content is less than 4 % by weight, the above reaction does not proceed sufficiently, so that the fire resistance of the refractory becomes inferior, and the bonding between particles becomes weak, so that the corrosion resistance also becomes low. On the other hand, when the iron content exceeds 8 % by weight, the amount of iron becomes excessive and the reaction proceeds too much, and as described above, the fire resistance and the corrosion resistance decrease due to the increase in pores and the liquid phase.

[0010] The particle size of silicon iron nitride is as follows.
The thickness is preferably 2 mm or less, but the following effects are particularly exhibited when the volume is 10 μm or less and 45% by volume or more. (1) The reaction area per weight and the frequency of contact with the aggregate and the like are increased, and the reactivity is improved. (2) The silicon nitride powder and the aggregate are uniformly mixed, the reaction of the refractory is made uniform, and the sinterability is improved. (3) The filling property of the refractory into the matrix is increased, and the structure is densified. In addition, the ratio of silicon iron nitride to aggregate is
It is preferable that the content is 50 to 50% by weight and the aggregate is 99 to 50% by weight.

[0011]

The present invention will be more specifically described below with reference to examples and comparative examples.

Examples 1-7 Comparative Examples 1-4 Silicon carbide powder (manufactured by Yakushima Denko Co., Ltd.), lozenge powder (produced by Goto), sintered alumina (manufactured by Showa Denko KK), coke powder (manufactured by Mitsubishi Chemical Corporation) Silicon iron nitride having various iron contents (maximum particle size: 0.2 mm) was mixed as shown in Table 1, and 18 to 21 parts by weight of tar was added to 100 parts by weight thereof.
The mixture was kneaded while keeping the temperature at about 70 ° C. The obtained kneaded product was formed into a square column shape, and then fired at a temperature of 1400 ° C. in an argon atmosphere to produce a sample, and the following hot bending strength, corrosion resistance and porosity were measured. Table 1 shows the results.

(1) Hot bending strength: A three-point bending strength at a temperature of 1400 ° C. was measured. (2) Corrosion resistance: The sample was immersed in a slag melted at 1500 ° C., the erosion depth was measured after holding the test piece for 3 hours while rotating, and a relative value was calculated with Comparative Example 1 being 100. The smaller the value, the better. (3) Porosity: measured by Archimedes' method.

[0014]

[Table 1]

Example 8 A test was conducted in the same manner as in Example 3 except that a silicon iron nitride powder having a particle size of 10 μm or less and 60% by volume was used. As a result, the hot bending strength was 89 kgf / cm ² , the corrosion resistance was 43, and the porosity was 30.2%.

[0016]

According to the present invention, it is possible to obtain silicon iron nitride capable of producing a refractory excellent in corrosion resistance and fire resistance (hot bending strength).

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C01B 21/082 C04B 35/66 C04B 35/00 CA (STN)

Claims (1)

(57) [Claims] An iron silicon nitride having an iron content of 4 to 8 % by weight.