KR20010060400A - Castable batch composition for blow pipe of blast furnace - Google Patents

Abstract

PURPOSE: Castable refractory compositions obtained by using mullite as aggregate of castable refractory and forming a dense texture resistant to corrosion using high purity alumina at a combining site are provided, which have excellent heat insulation property and corrosion resistance. CONSTITUTION: These compositions comprise a)40 to 60% by weight of mullite having a particle size of 3 to 10mm, b)30 to 45% by weight of mullite having a particle size of 0.5 to 3mm, c)3 to 10% by weight of alumina fine powder, d)2 to 5% by weight of silica fine powder, e)3 to 7% by weight of alumina cement, 0.3 to 0.9 parts by weight of vinyl fiber having a length of 1 to 10mm based on 100 parts by weight of the component a) to b) and g)0.05 to 0.5 parts by weight of sodium phosphate based on 100 parts by weight of the component a) to b).

Description

CASTABLE BATCH COMPOSITION FOR BLOW PIPE OF BLAST FURNACE}

[Industrial use]

The present invention relates to a castable refractory composition used for the interior of the blast furnace blower tube, and more particularly to a castable refractory composition for the blast furnace blower tube having excellent heat insulation and erosion resistance.

[Prior art]

In general, the inside of the blower pipe connected to the blast furnace for supplying the hot air to the blast furnace is constructed of castable refractory materials.In the case of a break caused by a momentary power failure or accident during operation, a mixture of pulverized coal, slack and molten iron is used. It flows back through the vents and penetrates deeply into the blower tube to solidify and then melt and flow down again when the air is blown back.

In order to solve the above problems, there are conventionally known technologies for blowable blower tubes, such as Japanese Patent Application Laid-Open Nos. 9-157045 and 10-1373, which are known to be highly fire resistant. It describes the use of ceramic hollow granules as aggregate, or refractory aggregate made from alumina and murite, transitional alumina as main components, and added slaked lime, silaki ultrafine powder, ceramic fiber, foaming agent, etc. It is described about manufacturing a heat insulating castable.

However, the above known techniques are all related to insulation refractory materials used in thermal casting cover of ladle, which is a tundish for continuous casting and molten steel transportation container in contact with an industrial furnace and molten steel, and these compositions have excellent thermal insulation effect but not excellent corrosion resistance. There is a problem that can not prevent damage due to the erosion of the refractory in the portion requiring erosion resistance to the mixture of pulverized coal, slack and molten iron, such as in the blast furnace blowing pipe (300 ~ 400 ℃).

The present invention is to solve the problems as described above, an object of the present invention is to use a crush-resistant fire resistant aggregate (Mullite: 3Al ₂ O ₃ ㆍ 2SiO ₂ ) while the heat conductivity is low as the aggregate of the castable refractory The joining part uses high-purity alumina to form a dense structure resistant to erosion, adjusts the shrinkage rate with silica powder, and forms fine pores at high temperature with organic fibers. It is to provide a composition.

In order to achieve the above object, the present invention

a) 40 to 60% by weight of lite having a particle size of 3 to 10 mm;

b) 30 to 45% by weight of lite having a particle size of 0.5 to 3 mm;

c) 3 to 10 weight percent of alumina powder;

d) from 2 to 5% by weight of silica;

e) 3 to 7% by weight of alumina cement;

f) 0.3 to 0.9 parts by weight of organic fibers based on 100 parts by weight of the components a) to e); And

g) 0.05 to 0.5 parts by weight of sodium phosphate based on 100 parts by weight of the components a) to e)

Provides a castable refractory composition for blast furnace blower pipe interior material comprising a.

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

Castable refractory composition for blast furnace blower pipe interior material of the present invention quantitate lite, sintered alumina powder, silica powder, alumina cement, organic fibers and sodium phosphate, and kneaded in a conventional kneader to prepare a mixture, and then prepared Moisture is added to the resulting mixture and kneaded for about 10 minutes to 1 hour.

The lite used in the castable refractory composition for the blast furnace ventilation pipe interior material of the present invention is more resistant to erosion than alumina, but is used as aggregate of the castable refractory because it has better fire resistance and lower thermal conductivity. The usual one used in the above is used.

In general, in the amorphous refractory used for the metal melting furnace, the optimum corrosion resistance and physical properties are difficult to penetrate the melt such as slag, molten iron, etc. when the structure of the construction body is the closest packing structure, but as shown in the present invention If required, when the structure of the construction is dense, the corrosion resistance is excellent, but the heat insulation is lowered. Therefore, in order to obtain a fireproof composition in which erosion resistance and heat insulation are harmonized, it is preferable to adjust the amount of mullite used for each particle size.

In the present invention, in order to prepare a castable refractory composition having excellent corrosion resistance and insulation, 40 to 60% by weight of a Moulite having a particle size of 3 to 10 mm and 30 to 45% by weight of a Mourite having a particle size of 0.5 to 3 mm are used. Preference is given to the total amount of the composition. When the non-lite is not used in a specific range for each particle size, the thermal conductivity of the refractory composition is increased or the erosion resistance is lowered, which is not preferable.

The alumina fine powder used in the present invention is used to prevent the penetration of melt such as molten iron and slack by densifying the bonding portion of the castable refractory composition. As the alumina fine powder of the present invention, sintered alumina, electrolytic alumina, calcined alumina, etc., which are produced differently according to the production method, may be used. The use of the sintered alumina fine powder is most preferable for preventing penetration of the melt.

The amount of the alumina fine powder is preferably 3 to 10% by weight, the amount of the alumina powder is less than 3% by weight, the structure of the body is not dense, the strength of the refractory composition is small, the erosion resistance is lowered, the amount of use exceeds 10% by weight In this case, the dispersion effect of the alumina raw material is excellent, the amount of water added is reduced, a dense structure is obtained, and the corrosion resistance is good, but the thermal conductivity is increased, which causes a problem that the heat insulation of the refractory composition is lowered.

The silica fine powder used in the present invention is a conventional one used in a refractory composition and is used to reduce the shrinkage ratio of the refractory composition. The amount of the silica powder used is preferably 2 to 5% by weight. If the amount of the silica powder is less than 2% by weight, the effect is difficult to exhibit, and if the amount of the silica powder is more than 5% by weight, there is a problem of increasing the expansion of the refractory composition. Therefore, it is preferable to keep the amount of the silica powder in a predetermined range.

Alumina cement used in the present invention is used to improve the bonding strength of the refractory composition at room temperature and about 1000 ℃. The alumina cement used is an alumina content of about 70% by weight and is used in a refractory composition, and the amount of the alumina cement used is preferably 3 to 7% by weight. When the amount is lowered and the amount used exceeds 7% by weight, the strength of the refractory composition increases at room temperature, but the erosion is severe due to the influence of the CaO component contained in the alumina cement and the structure becomes dense, resulting in an increase in thermal conductivity, thereby deteriorating the thermal insulation of the refractory composition. There is.

Organic fibers used in the present invention are used to improve the thermal insulation of the refractory composition at high temperatures. Various organic fibers may be used as the organic fibers used, but preferably vinyl fibers having a length of 1 to 10 mm, most preferably vinyl fibers having a length of about 4 mm. When the organic fiber is used at a high temperature, it is lost, so that fine pores are formed in the refractory composition, whereby the thermal conductivity is lowered, thereby improving thermal insulation of the refractory composition at a high temperature. The amount of the organic fiber is preferably used in the amount of 0.3 to 0.9 parts by weight based on 100 parts by weight of the content of the lite, alumina powder, silica powder and alumina cement components, the amount of the organic fiber is less than 0.3% by weight Since the amount of porosity generated is small, the effect of lowering the thermal conductivity of the refractory composition is small, and when the amount of use exceeds 0.9% by weight, the thermal conductivity of the refractory composition is lowered, but many pores are generated in the refractory, thereby reducing the corrosion resistance and strength of the refractory.

In addition, the sodium phosphate used in the castable refractory composition for the blast furnace blower pipe interior material of the present invention is added to facilitate the dispersing of the refractory composition components to promote kneading, the amount of the phosphate, alumina powder, silica It is preferable to use 0.05-0.5 weight part with respect to 100 weight part of content of fine powder and an alumina cement component.

In order to measure the physical properties of the refractory composition of the present invention prepared a specimen of a constant size and dried in the air for about 15 to 30 hours, and then dried for about 15 to 30 hours in a dryer of 80 to 150 ℃ temperature of the refractory composition Complete the specimen. After the prepared specimen was fired in an electric furnace at a temperature of 800 to 1500 ° C. for about 1 to 5 hours, the volume specific gravity, bending strength, erosion resistance test, thermal conductivity test, workability test, etc. of the prepared specimen were carried out in a conventional manner. Measure

The following presents preferred examples and comparative examples to aid in understanding the invention. However, the following examples are merely provided to more easily understand the present invention, and the present invention is not limited to the following examples.

(Example 1)

To the ingredients of the refractory composition shown in Table 1 to the basis of the content of Table 1 to dry kneaded in a universal kneading machine, and then kneading for about 30 minutes by adding water to prepare a castable refractory composition for blast furnace blower pipe interior materials It was. The refractory composition prepared above was molded in a mold (40x40x160) and naturally dried in air for about 24 hours, then dried in a dryer having a temperature of about 110 ° C. for about 24 hours, and the dried specimen was heated to a temperature of about 1000 ° C. The specimen was prepared by firing in a furnace. The prepared specimens were measured for specific gravity and bending strength in a conventional manner. Erosion resistance of the prepared refractory composition prepared by using a rotary erosion tester equipped with a burner using oxygen-propane gas as a heat source to dissolve the prepared slag containing Fe ₂ O ₃ and CaO as a main component, and then the temperature about 1550 It was measured by measuring the erosion depth of the specimen was poured by holding the slag for about 1 hour at ℃. The thermal conductivity of the prepared specimen was measured at about 1000 ℃ by heating the specimen (bottle-shaped lead and three sheets) baked at about 1200 ℃. The workability of the prepared specimen was measured by considering the spread state of the sample after putting the sample kneaded in the kneader into the mold of the fluidity tester and hitting it 30 times. Physical properties measured above are shown in Table 2 below.

(Examples 2 to 6)

As shown in Table 1 below, except that the content of the composition was different, the specimens of the refractory composition were prepared in the same manner as in Example 1, and the physical properties of the prepared specimens were measured in the same manner as in Example 1, The results are shown in Table 2 below.

(Comparative Examples 1 to 5)

As shown in Table 1 below, except that the content of the composition was different, the specimens of the refractory composition were prepared in the same manner as in Example 1, and the physical properties of the prepared specimens were measured in the same manner as in Example 1, The results are shown in Table 2 below.

Ingredient (g) Example Comparative Example One 2 3 4 5 6 One 2 3 4 5 Mourite 3-10mm 50 60 60 40 45 50 50 38 48 55 55 0.5-3mm 30 30 30 45 45 35 28 45 40 30 30 Sintered Alumina Powder 10 3 3 7 5 3 10 10 - 13 5 Silica powder 5 2 2 3 2 5 5 2 5 - 3 Alumina cement 5 5 5 5 3 7 7 5 7 2 7 Vinyl fiber ¹⁾ 0.3 0.9 0.7 0.6 0.6 0.5 0.3 0.5 0.5 0.5 - Sodium Phosphate ²⁾ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

The vinyl fiber of (1) and the sodium phosphate of 2) are parts by weight based on 100 parts by weight of the content of lite, sintered alumina fine powder, silica powder and alumina cement)

Example Comparative Example One 2 3 4 5 6 One 2 3 4 5 Volume specific gravity (1000 ℃) 2.43 2.40 2.41 2.43 2.43 2.46 2.63 2.56 2.69 2.67 2.75 Bending strength (1000 ℃, kg / cm2) 225 180 200 215 190 185 130 105 98 90 150 Erosion Depth (mm) 3.0 2.9 3.0 3.3 2.9 3.2 7.0 6.5 8.0 9.0 3.0 Thermal Conductivity (1000 ℃, Kcal / mh- ℃) 1.72 1.65 1.69 1.70 1.70 1.75 3.2 3.0 3.3 3.21 3.5 Workability O O O O O O △ X X X X

(O: Good, △: Normal and x: Poor)

As can be seen in Table 2, the refractory compositions of Examples 1 to 6 manufactured within the range of components and contents of the present invention have physical properties such as bending strength, erosion resistance, workability, etc., compared to the refractory compositions, which are not within the scope of the present invention. Excellent heat insulation with low thermal conductivity.

The castable refractory composition for the blast furnace blower pipe interior material of the present invention is a refractory aggregate using a light-free, high purity alumina in the joining portion, by adjusting the shrinkage rate with silica powder and forming fine pores at high temperature with organic fibers, insulation and resistance Excellent erosion

Claims (3)

a) 40 to 60% by weight of lite having a particle size of 3 to 10 mm; b) 30 to 45% by weight of lite having a particle size of 0.5 to 3 mm; c) 3 to 10 weight percent of alumina powder; d) from 2 to 5% by weight of silica; e) 3 to 7% by weight of alumina cement; f) 0.3 to 0.9 parts by weight of vinyl fiber based on 100 parts by weight of the component a) to e); And g) 0.05 to 0.5 parts by weight of sodium phosphate based on 100 parts by weight of the components a) to e) Castable refractory composition for blast furnace blower pipe interior material comprising a. The castable refractory composition for blast furnace blow pipe interior materials according to claim 1, wherein the alumina fine powder of c) is one selected from the group consisting of sintered alumina, electrolytic alumina and calcined alumina. The castable fire resistant composition according to claim 1, wherein the f) vinyl fiber has a length of 1 to 10 mm.