KR101449184B1 - Batch Composition for Blast Furnace Tap Hole - Google Patents

Abstract

The present invention relates to a refractory composition for a blast furnace outlet, and more particularly to a refractory composition for a blast furnace outlet containing an alumina clinker, a spinel (MgAl ₂ O ₄ ) clinker, silicon carbide (SiC) will be.
According to the present invention, it is possible to obtain a refractory composition for a blast furnace outlet which has improved strength, scrubbing resistance, erosion resistance and invasion resistance without using alumina cement which is generally used as a binder for an alumina-based inflow material.

Description

Technical Field [0001] The present invention relates to a refractory composition for a blast furnace,

More particularly, the present invention relates to a refractory composition for use as a fire extinguishing composition for a furnace exit which can be used as an inflow material for a core material, which is a passage through which molten iron discharged from a blast furnace flows during a refining process, .

In general, the molding material constituting the blast furnace outlet is eroded by the scattering of molten iron and molten iron at the time of leaving at the time of leaving, and is used in a harsh atmosphere where heat shock is received by cooling when the exit is completed.

Although the construction method was conventionally applied by air rammer, it is difficult to work for a long period of time in a harsh working environment where high heat and dust are present. In recent years, due to the introduction of castable, The time is shortened and the need for a refractory having good erosion resistance is required for the reduction of the number of repair.

In general, alumina-based refractories are characterized in that they have excellent corrosion resistance to molten steel and slag, and various types of amorphous refractories using alumina as main materials are being developed.

Among these unshaped refractories, unshaped refractories for use in the inflow are particularly advantageous because of their simple construction. However, since the alumina-based inflow material using alumina as the main material as the inflow material is mostly used as a binder, a large amount of alumina cement must be used, which is disadvantageous in that it is easily damaged by molten steel or slag.

The alumina cement used as the binder is prepared by mixing alumina aggregate and fine powder, adding water, kneading the mixture, and allowing the molding material to exhibit strength within a short period of time of 24 hours by hydration reaction during the inflow molding. By weight of alumina cement is used.

As described above, the alumina cement has an advantage of imparting the strength of the indefinite material in a short time, but at a high temperature, a low melting point material including MgO, Al ₂ O ₃ , CaO and SiO ₂ is contained in the matrix portion, There is a disadvantage that the low melting point material flows out and promotes the melting loss of the refractory material.

In addition, such low melting point materials can penetrate through the pores in the refractory structure together with the external slag and react with the aggregate and the matrix in the structure to produce a denatured layer. The damaged layer thus generated causes structural spalling, and the structural spalling may cause the refractory to be peeled and damaged.

Aluminous inflow materials having such defects, including alumina cement, reduce the inherent advantages of highly corrosion-resistant alumina materials, and therefore it is essential to reduce the amount of alumina cement used to solve such problems.

Therefore, it is expected that the refractory composition for an outflow port with excellent resistance to abrasion, erosion resistance and invasiveness without using alumina cement can be usefully used in related fields.

Accordingly, one aspect of the present invention is to provide a refractory composition for use in an outlet of a blast furnace having excellent effects without using alumina cement.

According to one aspect of the present invention, there is provided a refractory composition for a blast furnace outlet comprising a basic component consisting of alumina clinker, spinel (MgAl ₂ O ₄ ) clinker, silicon carbide (SiC), carbon containing powder and calcined alumina.

Wherein the refractory composition comprises 56 to 64 wt.% Alumina clinker, 18 to 20 wt.% Spinel (MgAl ₂ O ₄ ) clinker, 10 to 12 wt.% Silicon carbide (SiC), 3 to 5 wt.% Carbonaceous powder, 7% by weight.

The carbon-containing powder is preferably at least one selected from the group consisting of graphite powder and coke powder.

The average particle diameter of the carbon-containing powder is preferably 0.5 to 3 mm.

The spinel (MgAl ₂ O ₄ ) clinker powder preferably has an average particle diameter of 0.074 mm or less.

The calcined alumina is preferably an ultrafine powder calcined alumina having an average particle diameter of 0.5 mu m or less.

It is preferable that the refractory composition further comprises at least one member selected from the group consisting of silica flour, boron carbide powder (B4C), sodium hexametaphosphate, and a curing retarder.

The refractory composition comprises 1.0 to 3.0 parts by weight of silica flour, 0.5 to 2 parts by weight of boron carbide powder (B4C), 0.1 to 0.4 parts by weight of sodium hexametaphosphate, 0.02 to 0.04 part by weight of a retarder.

The hardening retarder is preferably at least one selected from the group consisting of citric acid and boric acid.

The refractory composition may be used as an inflow material for a blast furnace wire.

According to the present invention, it is possible to obtain a refractory composition for a blast furnace outlet which has improved strength, scrubbing resistance, erosion resistance and invasion resistance without using alumina cement which is generally used as a binder for an alumina-based inflow material.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

The present invention relates to a refractory composition which can be used as an inflow material of a cast steel which is a passage through which molten iron discharged from a blast furnace flows during a refining process. The refractory composition for a furnace exit of the present invention comprises alumina clinker, spinel (MgAl ₂ O ₄ ) (SiC), carbon-containing powder, and calcined alumina.

More preferably, the basic component of the refractory composition of the present invention comprises 56 to 64 wt% of alumina clinker, 18 to 20 wt% of spinel (MgAl ₂ O ₄ ) clinker, 10 to 12 wt% of silicon carbide (SiC) 3 to 5 wt% and calcined alumina 5 to 7 wt%.

The purity of the alumina clinker which can be used in the present invention is preferably not less than 98% of alumina (Al ₂ O ₃ ) content in order to maintain the refractory resistance of the refractory composition at a high level, and it is preferable to use any of sintered alumina clinker or fused alumina clinker However, it is preferable to use a fused alumina clinker in order to obtain high corrosion resistance.

The alumina clinker is preferably contained in an amount of 56 to 64% by weight, more preferably 58 to 62% by weight, based on the weight of the base component of the refractory composition for the entire furnace outlet.

When the content of alumina clinker is less than 56% by weight, it is difficult to obtain high corrosion resistance against molten steel or slag. When the content of alumina clinker is more than 64% by weight, the content of components added to improve corrosion resistance and invasion resistance Is too small, it may be difficult to obtain characteristics of a desired refractory composition.

Preferably, the spinel (MgAl ₂ O ₄ ) clinker powder has an average particle diameter of 0.074 mm or less. If the average particle diameter of the clinker powder exceeds 0.074 mm, the FeO component can not be prevented from penetrating.

The above-mentioned spinel (MgAl ₂ O ₄ ) clinker powder is preferably contained in an amount of 18 to 20 wt%, more preferably 18.5 to 19.5 wt%, based on the weight of the base component of the refractory composition for the entire furnace outlet. .

If the content of the spinel (MgAl ₂ O ₄ ) clinker is less than 18% by weight, there is a problem in resistance to infiltration. If the content is more than 20% by weight, there is a problem in corrosion resistance.

The silicon carbide (SiC) is preferably contained in an amount of 10 to 12 wt%, and more preferably 10.5 to 11.5 wt%, based on the weight of the base component of the refractory composition for the entire furnace outlet.

Silicon carbide (SiC) serves to prevent oxidation of carbon components and further increases corrosion resistance to molten iron and blast furnace slag. Therefore, when the content of silicon carbide (SiC) is less than 10% by weight, the corrosion resistance is insufficient However, when the content exceeds 20% by weight, the corrosion resistance tends to deteriorate.

The carbon-containing powder of the present invention is used for the purpose of preventing wettability of slag and enhancing thermal shock resistance, and may be at least one selected from the group consisting of graphite powder and coke powder, but is not limited thereto. For example, artificial graphite powder can be used as the graphite powder.

The average particle diameter of the carbon-containing powder is preferably 0.5 to 3 mm, and when the average particle diameter is less than 0.5 mm, the oxidation resistance of the refractory composition is deteriorated and the workability is lowered. There is a problem that the improvement of the erosion resistance and the resistance to invasiveness, which are inherent roles, is insignificant.

On the other hand, the carbon-containing powder is preferably contained in an amount of 3 to 5% by weight, and more preferably 3.5 to 4.5% by weight, based on the weight of the base component of the refractory composition.

When the content of the carbon-containing powder is less than 3% by weight, the effect of corrosion resistance and invasiveness against slag is deteriorated. When the content of the carbon-containing powder is more than 5% by weight, there is an undesirable problem in terms of ensuring oxidation resistance and workability.

The calcined alumina is preferably an ultrafine powder calcined alumina having an average particle diameter of 0.5 μm or less. When calcined alumina having an average particle diameter within the above range is used, the calcined alumina increases the fluidity of the refractory composition, Thereby improving the dry strength.

The calcined alumina is preferably contained in an amount of 5 to 7% by weight, and more preferably 5.5 to 6.5% by weight based on the weight of the base component of the refractory composition for the entire furnace outlet.

When the content of the carbon calcined alumina is less than 5% by weight, the flowability of the refractory composition is lowered and the dry strength is lowered. When the content is more than 7% by weight, the flowability is lowered and the cost is increased. There is an undesirable problem.

Furthermore, the refractory composition preferably further comprises at least one member selected from the group consisting of silica flour, boron carbide powder (B4C), sodium hexametaphosphate, and a curing retarder.

More preferably, the refractory composition comprises 1.0 to 3.0 parts by weight of silica flour, 0.5 to 2 parts by weight of boron carbide powder (B4C) 0.1 to 0.4 parts by weight of sodium phosphate and 0.02 to 0.04 part by weight of a curing retarder.

Silica flower is a component that imparts fluidity, improves dry strength, and maintains bond strength at an intermediate temperature range of 600 to 1000 ?. When the silica flour is contained in an amount of more than 3.0 parts by weight per 100 parts by weight of the base component, the flowability of the refractory composition is lowered and the alumina-magnesia-silica based low melting point material is produced, There is a problem of deterioration.

The boron carbide powder (B4C) is added to improve the oxidation resistance of the carbon contained in the refractory composition. When the amount of the boron carbide powder is more than 2.0 parts by weight per 100 parts by weight of the base component, the corrosion resistance is lowered .

Sodium hexametaphosphate serves as a dispersant in the refractory composition of the present invention, and when it is added in an amount exceeding 0.4 parts by weight per 100 parts by weight of the base component, the fluidity and corrosion resistance of the refractory composition tend to be lowered.

Meanwhile, the refractory composition of the present invention may contain a curing retarder, but if it contains more than 0.04 parts by weight per 100 parts by weight of the base component, the fluidity of the refractory composition during kneading is seriously deteriorated and kneading itself becomes difficult .

The curing retarder is preferably at least one selected from the group consisting of citric acid and boric acid, but is not limited thereto.

According to the present invention, it is possible to obtain a refractory composition for a blast furnace outlet having improved strength, anti-scratch resistance, anti-erosion resistance and resistance to infiltration without using alumina cement used as a binder of an alumina-based inflow material. The refractory composition may be used as an inflow material for the blast furnace wire.

The refractory composition of the present invention can be prepared by simply mixing the above components, and the production method is not particularly limited thereto. More preferably, the refractory composition of the present invention is further prepared by adding water, And is added in an amount of 4 to 7 parts by weight per 100 parts by weight of the base component.

Hereinafter, the present invention will be described more specifically by way of specific examples. The following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

1. Blast Furnace For exit  Preparation of refractory composition

A refractory composition for an exit port was prepared using the components shown in Table 1 below. At this time, the refractory composition of the present invention is composed of alumina clinker, spinel (MgAl ₂ O ₄ ) clinker, silicon carbide (SiC), artificial graphite crushed material and ultrafine powder calcined alumina as basic components, The weight% of each component when the sum is 100% by weight is shown in the following Table 1.

On the other hand, the additional components including silica flower, boron carbide powder (B4C), alumina cement, sodium hexametaphosphate and citric acid are added in an amount of 100 parts by weight per 100 parts by weight of the base component, Respectively.

Water is added at the time of manufacturing the refractory composition of the present invention. Water serves to impart fluidity, and the amount added per 100 parts by weight of the base component is shown in Table 1 as parts by weight.

division Example Comparative Example One 2 One 2 3 4 5 6 7 8 9 Basic ingredient Alumina clinker 56 64 61 62 60 56 60 58 58 58 57 Spinel (MgAl ₂ O ₄ )
Clinker 20 18 15 18 20 20 20 20 20 20 18 Silicon carbide (SiC) 12 10 12 8 12 10 12 10 10 10 10 Artificial graphite powder 5 3 5 5 One 7 5 5 5 5 5 Ultra-fine calcined alumina 7 5 7 7 7 7 3 7 7 7 0 Additional ingredient Silica flower One 2 One One One One One 4 One One One B4C powder 0.5 1.5 0.5 0.5 0.5 0.5 0.5 0.5 0 3 0.5 Alumina cement - - - - - - - - - - 10 Sodium hexametaphosphate 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Citric acid 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 water 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0

2. Evaluation of workability

Evaluation of the workability of the refractory compositions of the examples and comparative examples prepared in the above 1. was carried out as follows.

(1) Flow rate

The fluidity value was measured by placing a flow cone having an inner diameter of 100 mm on the center of a metallic disk of a flow meter, filling each 1 kg of the kneaded sample, removing the flow cone, do. At this time, the specimen on the disk spreads broadly according to the fluidity due to the upside and downside impact of the disk. After 15 strokes, the longest and shortest portions of the flowed material were measured and the average value was defined as the flow rate, that is, the flow value. If the flow value is usually 140 or more, it can be judged that the workability is good. The measurement results are shown in Table 2 below.

(2) Curvature

The specimen size for the bending strength measurement was 40 mm × 40 mm × 160 mm. After 24 hours of curing, the specimens were demolded, dried at 110 ° C. for 24 hours, and then used in the test using the three-point bending strength tester. The measurement results are shown in Table 2 below.

(3) Oxidation resistance

The oxidation resistance was determined for each specimen at 1400 DEG C for 3 hours After the oxidation test, the specimens were cut and the ratios of decarburized area were determined to compare the oxidation resistance. The higher the decarburized area ratio, the worse the oxidation resistance. The measurement results are shown in Table 2 below.

(4) Thermal shock resistance

The thermal shock resistance was evaluated by comparing the resistance to thermal shock. The degree of cracking was evaluated by repeating the cooling at room temperature for 5 minutes after holding at 1350 ° C for 30 minutes, and the measurement results are shown in Table 2 below.

(5) Erosion test

The specimen size for the measurement of erosion resistance was 118 mm (rear side) x110 mm (height) x40 mm (thickness) x 82 mm (front side) size. After 24 hours of curing, the specimen was dried at 110 ° C for 24 hours. Each of eight specimens was assembled into a cylindrical shape at the same time to carry out an erosion test, and the measurement results are shown in Table 2 below.

The depth of erosion and the depth of penetration were measured by rotating erosion test at 1500 ° C -1550 ° C for 6 hours using molten iron as an erosion agent in consideration of easiness of erosion test. Respectively.

(6) degree of curing

The evaluation of the degree of hardening was visually evaluated as to the degree of hardening of the test piece with time, and the measurement results are shown in Table 2 below.

division Example Comparative Example One 2 One 2 3 4 5 6 7 8 9 Flow (mm) 150 170 160 150 170 130 135 130 160 160 160 Whether there is a sharpness (degree of hardening) Good Good Good Good Good Good Good Good Good Good Good Ruggedness
(kg / cm ² ) 110 ° C x24h 55 60 60 60 65 40 40 65 50 50 55 1000 ° C x 3h 70 75 70 65 75 40 45 70 60 60 75 1500 ° C x 3h 120 110 120 100 110 70 70 120 125 90 130 Oxidation resistance 1400 ° C x 3h O O O x O x △ O x O O Thermal shock resistance O O O O x O O O O x △ Erosion depth (mm) 5 5 10 10 9 8 10 12 8 8 12 Depth of penetration (mm) One One 6 One 5 One 3 One One One One

3. Sintering

As can be seen from the results of Table 2, it can be seen that the characteristics of the refractory composition of Examples 1 and 2, which satisfy the range of the present invention, are better than those of Comparative Examples 1 to 9.

That is, in Comparative Example 1, the addition amount of spinel was out of the range of the present invention, and the infiltration resistance was lowered. In Comparative Example 2, the addition amount of silicon carbide deviated from the range of the present invention, and the oxidation resistance and corrosion resistance were remarkably lowered Can be confirmed. On the other hand, in Comparative Example 3 and Comparative Example 4, the content of the graphite crushed material was outside the scope of the present invention, indicating that the spraying resistance, the resistance to infiltration, the corrosion resistance, the flowability and the strength were remarkably decreased. Further, in Comparative Example 5, the ultrafine powder calcined alumina was added in an amount less than that of the present invention, and the drying strength was weak and the workability was insufficient.

On the other hand, as in Comparative Example 6, the flowability to which the silica flower is excessively added may be lowered and the corrosion resistance may be lowered. As can be seen in Comparative Example 7 and Comparative Example 8, the addition of the antioxidant B4C may improve the fire resistance If it is added excessively, the corrosion resistance and thermal shock resistance may be deteriorated. In Comparative Example 9, alumina cement was added as a binder and the corrosion resistance was remarkably lowered.

As described above, it can be confirmed that the refractory composition of the present invention is excellent in resistance to corrosion and resistance to blast furnace wire and slag.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

Claims (10)

A refractory composition for an inlet material of a high-
Alumina clinker 56 to 64% by weight, spinel (MgAl ₂ O ₄₎ clinker from 18 to 20 wt.%, Silicon carbide (SiC) 10 to 12% by weight, a carbon-containing powder, 3 to 5% by weight and a calcined alumina of 5 to 7% by weight Comprising a basic component,
1.0 to 3.0 parts by weight of silica flour per 100 parts by weight of the base component, 0.5 to 2 parts by weight of boron carbide powder (B ₄ C), 0.1 to 0.4 parts by weight of sodium hexametaphosphate, 0.02 to 0.04 parts by weight,
Wherein the carbon-containing powder is at least one selected from the group consisting of graphite powder and coke powder.
delete delete The refractory composition according to claim 1, wherein the carbon-containing powder has an average particle diameter of 0.5 to 3 mm.
The refractory composition according to claim 1, wherein the spinel (MgAl ₂ O ₄ ) clinker powder has an average particle size of 0.074 mm or less.
The refractory composition according to claim 1, wherein the calcined alumina is an ultrafine powder calcined alumina having an average particle diameter of 0.5 m or less.
delete delete The refractory composition according to claim 1, wherein the curing retarder is at least one selected from the group consisting of citric acid and boric acid.
delete