JPH0737342B2 - Spray repair material for blast furnace tappipe - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a spray repair material for blast furnace tap gutters.

Conventional technology and its problems In recent years, in the steelmaking process, in order to improve productivity and reduce the unit price, even in the blast furnace casting floor, etc.
Processing such as P removal came to be performed. These treatments in the blast furnace casting floor are a method of blowing the treating agent together with the carrier gas into the hot metal by a lance in the hot-dip and hot-water spouts capable of retaining the hot metal for a certain period of time. This tends to significantly increase damage to the lining, especially local melting damage such as slag lines. BACKGROUND ART Conventionally, spray repair has been performed to repair local melting damage points such as a slag line in a tap iron gutter of a blast furnace casting and a hot metal gutter. This is a method in which a mixed material composed of a refractory raw material and a binder is sprayed while being mixed with water at the tip of a nozzle, and the refractory raw material includes alumina-silicon carbide-carbon system, alumina-
Silica-silicon carbide type and the like are used, and as the binder, alumina cement, sodium phosphate and the like are used. However, the conventional sprayed material is 1) especially when de-Si treatment is performed.
FeO in the slag, silicon carbide and carbon are oxidized by Fe ₂ O ₃ etc. to produce SiO ₂ and CO _2, and further SiO ₂ and Fe ₂ O ₃ react to produce a low melting point substance, Since it has low corrosion resistance and 2) uses alumina cement or the like having low hot strength as a binder, it has drawbacks such as poor wear resistance, and therefore its durability is not satisfactory.

In order to solve the above problems, attempts have been made to use neutral materials such as alumina, basic materials such as magnesia, magnesia chrome (hereinafter referred to as magcro), and the like. However, the alumina material is originally SiO ₂ -Fe
Corrosion resistance to ₂ O ₃ slag is low, so durability is insufficient. Further, the magnesia material is susceptible to the penetration of slag, so that structural spalling occurs and the durability is not sufficiently improved. As is known to be more durable than slag having a composition similar to that of desiliconized slag, magchromic materials are used as calcined magcro bricks in metal refining furnaces, etc. It is effective for improving durability. However, when this is used as a spray material, since the sintering of magnesia and chrome ore does not proceed sufficiently, stable picrochromatography (MgO ・ Cr ₂ O ₃ ) especially against SiO ₂ -Fe ₂ O ₃ slag Is not generated, and therefore the durability is not sufficiently improved.

Means for solving the problem The present invention, as a result of repeated devoted research in view of the problems of the above-mentioned conventional techniques, as a main component of the magcro material, using an electro-fused magkuro containing a picrochromite phase, Moreover, it was found that a spray repair material having extremely excellent corrosion resistance and hot strength can be obtained by using, as a binder, an alumina sol powder having a low flux content and reacting with a micro material to generate a high melting point substance. The present invention has been completed.

That is, the present invention is a spray for blast furnace tappipe containing 100 parts by weight of a magnesia chromium-based refractory raw material containing 10 to 60% by weight of electrofused magnesia chromium, 0.5 to 3 parts by weight of marminasol powder, and 0.3 to 1.5 parts by weight of phosphate. Related to repair materials.

In the present invention, as the main component of the magro refractory raw material, especially Si
An electrofused magcro containing a picrochromatographic phase that is stable against O ₂ —Fe ₂ O ₃ slag is used. As the electromelting magro, any one having a Cr ₂ O ₃ content of 10% or more and a SiO ₂ content of 3% or less and a bulk specific gravity of 3.60 or more can be used. The blending amount of the electro-melting magro is about 10 to 60% by weight of the total amount of the magro refractory raw material. If it is less than 10%, the effect of improving the corrosion resistance is not sufficient, while if it exceeds 60% by weight, the effect does not change so much and it is uneconomical.

As the maguro-based refractory raw material other than the electro-melted maguro, usual ones can be used, and examples thereof include magnesia, chrome ore, sintered magkuro, and reclaimed fired maguro brick. However, considering the corrosion resistance of the repair material, the Cr ₂ O ₃ content of 1
0% or more, Al ₂ O ₃ content 35% or less, Fe ₂ O ₃ content 20% or less, SiO
_{2 It} is desirable to use one with a content of 7% or less. In the present invention, one type or two or more types of the above-mentioned maguro-based refractory raw material are used.

The particle size of the magro refractory raw material including electro-melted magro is not particularly limited and may be appropriately selected. Usually, coarse particles with a diameter of 5 to 1 mm are about 30 to 50%, and intermediate particles with a diameter of about 1 to 0.074 mm. 20
What contains about 40% to about 40% and 20 to 40% of fine powder of 0.074 mm or less may be used.

Alumina sol powder becomes ultrafine particles of alumina at high temperature, and reacts with FeO in magnesia or slag to form a stable spinel phase. As the alumina sol powder, any of the usual ones can be used, and examples thereof include those obtained by drying an alumina sol aqueous solution stabilized with an organic acid such as acetic acid with a spray dryer or the like. However, considering the hot strength of the repair material, it is desirable to use an Al ₂ O ₃ content of about 60% or more and an average particle size of about 80 μm. The blending amount of the alumina sol powder is about 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the magro refractory raw material. If it is less than 0.5 parts by weight, the effect of improving the hot strength is not sufficient, while if it exceeds 3.0 parts by weight, the viscosity of the material increases and the mixing at the time of spraying becomes insufficient, so that a uniform work body cannot be obtained.

In the present invention, the addition of phosphate increases the adhesive strength of the repair material of the present invention and reduces rebound loss. As the phosphate, any of those having a P ₂ O ₅ content of 40% or more can be used, and examples thereof include condensed sodium phosphate such as sodium pyrophosphate, sodium tetrapolyphosphate, and sodium hexametaphosphate, aluminum phosphate, silicon phosphate. Etc. can be mentioned. The amount of phosphate compounded is maguro series refractory raw material
0.3 to 1.5 parts by weight per 100 parts by weight. If it is less than 0.3 parts by weight, rebound loss and the like increase and work efficiency deteriorates, while if it exceeds 1.5% by weight, it reacts with magcro material or alumina sol at high temperature to form a low melting point substance,
Reduces hot strength.

The repair material of the present invention, a predetermined amount of each of the above components, according to a conventional method,
For example, it is produced by mixing with an Erich mixer or the like.

In repairing a tappipe, a hot metal gutter, etc. using the repair material of the present invention, any spraying repair method conventionally used in this field can be adopted.

EFFECTS OF THE INVENTION The blast furnace tap iron spout repair material of the present invention has extremely excellent corrosion resistance and hot strength, and exhibits remarkably high durability.

EXAMPLES The present invention will be further clarified by giving Examples and Comparative Examples below. In addition, as the magro series refractory raw material, the one having the composition shown in Table 1 below was used.

Examples 1 to 5 Alumina sol powder (Al ₂ O ₃ content 67%, average particle size 60 μ) was added to 100 parts by weight of magcro refractory raw materials in the mixing ratio shown in Table _2.
m) and phosphate were added and mixed in an Erich mixer to obtain the repair material of the present invention. As the phosphate, sodium hexametaphosphate (Na ₂ O content 33.7%, P ₂ O ₅ content 62.3% was used. )
Alternatively, silicon phosphate 8 SiO ₂ content 50%, P ₂ O ₅ content 21%) was used.

The obtained repair material was subjected to a corrosion resistance test and hot strength measurement. The test sample was prepared as follows. That is, the repair material is sprayed with a spray can (lead can) at room temperature at a discharge pressure of 1.5K.
g / cm ² , discharge rate 10 Kg / min, 200 × 300 m on alumina brick
Sprayed in a range of m with a thickness of 100 mm. This at 110 ℃ 20
40 hours after drying for 3 hours and then baking at 900 ° C for 3 hours
A sample of × 40 × 160 mm was cut out. The corrosion resistance test was carried out by the rotating drum method which is commonly used as a corrosion resistance test for refractory materials. As erosion agents, SiO ₂ 40%, Fe ₂ O ₃ 40%, C
Slag having a composition of aO5% and MnO15% was used, and the condition was 1600 ° C. × 3 hours. The hot strength was measured according to ASTM C538-76 at 1000 ° C and 1400 ° C in sequence. For sample preparation,
Workability at the time of spraying repair material was also judged. The results are shown in Table 4.

Comparative Examples 1 and 2 Conventional repair materials were obtained in the same manner as in the examples with the compounding ratios (parts by weight) shown in Table 3. The obtained repair material was subjected to the same performance test as in the example. The results are shown in Table 4.

From Table 4, it can be seen that the repair material of the present invention is significantly superior to the conventional repair material in corrosion resistance and hot strength.

Claims (1)

[Claims] 1. Spraying for blast furnace tap pipe containing 100 parts by weight of magnesia chromium refractory raw material containing 10 to 60% by weight of electro-melted magnesia chromium, 0.5 to 3 parts by weight of alumina sol powder and 0.3 to 1.5 parts by weight of phosphate. Repair material.