KR101070479B1 - Refractory Composition of a Flowing Material for Use of Steel Manufacture Ladle - Google Patents

Abstract

The present invention relates to a refractory composition of the inflow material for steelmaking ladle, 65 to 70% by weight of alumina clinker, 20 to 25% by weight spinel clinker powder, 5 to 10% by weight of calcined alumina powder, 1 to 3.0% by weight of silica flower powder, hexa Provided is a fire resistant composition of an inflow material for steelmaking ladle comprising 0.1 to 0.4% by weight of sodium metaphosphate and 0.02 to 0.04% by weight of citric acid. The refractory composition of the inflow material for steelmaking ladle according to the present invention has the effect of improving the corrosion resistance and invasion resistance.

Inlet for Steelmaking Ladle, Refractory Composition, Erosion Resistance, Wetting Resistance, Alumina Clinker

Description

Refractory Composition of a Flowing Material for Use of Steel Manufacture Ladle}

The present invention relates to a fire resistant composition of the inflow material for steelmaking ladle. More specifically, the present invention provides high corrosion resistance and infiltration resistance which is prepared by using ultrafine calcined alumina and ultrafine silica flower as a binder, without using alumina cement which is usually used as a binder of an alumina inflow material. A spinelil amorphous refractory composition.

In general, alumina refractories have characteristics of excellent corrosion resistance to molten steel and slag, and various amorphous refractory materials based on alumina have been developed. For example, refractories for walls and floors of ladle during steelmaking process Can be.

Among the amorphous refractory materials, the irregular refractory material for inflow construction is highly used because of its simple construction. However, the alumina inflow material using alumina as the main material as the inflow material has a disadvantage in that in most cases, a large amount of alumina cement is used as the binder, so that the molten steel or slag is easily melted. The alumina cement used as the binder is mixed with alumina aggregate and fine powder to add water, and after kneading, the molding material exerts its strength as a furnace body in a short time within 24 hours by hydration reaction. 12% of alumina cement is used.

As described above, the alumina cement has the advantage of imparting the strength of the amorphous 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 included in the matrix at a high temperature. There is a disadvantage that the material is leaked to promote the melting loss of the refractory material. In addition, the low melting point material penetrates through pores in the refractory tissue together with external slag, and the penetrated material reacts with aggregate and matrix in the tissue to create a deteriorated layer. The altered layer thus produced causes structural spalling, and the refractory is peeled off by such structural spalling. Since the alumina cement-bonded alumina inflow material having such a defect reduces the inherent advantages of the alumina material having excellent corrosion resistance, it is essential to reduce the amount of alumina cement used to solve this problem.

In order to solve the problems of the conventional alumina influx as described above, the inventors have conducted research and experiments and proposed the present invention based on the results.

The present invention uses ultrafine alumina and silica flower as a binder instead of the alumina cement used as a binder for the alumina inflow material to improve corrosion resistance and infiltration resistance, which is a defect of the alumina inflow material, and at the same time, excellent alumina inflow material. The purpose is to provide.

The above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention is 65 to 70% by weight alumina clinker, 20 to 25% by weight spinel clinker powder, 5 to 10% by weight calcined alumina powder, 1 to 3.0% by weight silica flower powder, 0.1 hexametaphosphate 0.1 It provides a refractory composition of the inlet for steelmaking ladle comprising 0.4 to 0.4% by weight and 0.02 to 0.04% by weight citric acid.

The purity of the alumina clinker may be 98% or more of alumina (Al ₂ O ₃ ) content.

The particle size of the spinel clinker powder may be 0.074 mm or less.

The particle size of the calcined alumina powder may be 0.5 μm or less.

Hereinafter, the present invention will be described in detail.

The present invention is based on 65 to 70% by weight of alumina clinker, 20 to 25% by weight spinel clinker powder, 5 to 10% by weight calcined alumina powder as the basic composition, and 1.0 to 3.0% by weight of silica flower powder by extrapolation to the basic composition, hexa The present invention relates to a fire resistant composition of a ladle wall or floor inflow material, which is added by adding 0.1 to 0.4% by weight of sodium metaphosphate and adding 0.02 to 0.04% by weight of citric acid as a curing retardant.

In the present invention, in order to achieve the above object, it is preferable to use 65 to 70% by weight of alumina clinker, 20 to 25% by weight of spinel clinker powder, and 5 to 10% by weight of calcined alumina powder as the basic composition. The reason is as follows.

The purity of the alumina clinker used in the present invention is preferably used that the content of alumina (Al ₂ O ₃ ) of 98% or more in order to maintain the high refractory degree of inflow material, and use either sintered alumina clinker or electrolytic alumina clinker In order to obtain high corrosion resistance, it is preferable to use an electrolytic alumina clinker. Alumina clinker should be 65 ~ 70% by weight as main raw material. Here, the limited content of the alumina clinker means that the remaining portion except for the spinel clinker fine powder added to improve the infiltration resistance and the calcined alumina powder, which is a binder, is used as a fire resistant aggregate, and in order to obtain high corrosion resistance to molten steel or slag, It is effective to contain alumina.

The spinel clinker powder should use a particle size of 0.074mm or less due to the particle size of the inlet material, the addition amount should be 20 to 25% by weight. The reason for limiting the amount of spinel clinker added here is effective in improving the infiltration resistance to slag.

The calcined alumina is preferably used 5 to 10% by weight of calcined alumina powder of 0.5㎛ or less. The use of calcined alumina powder increases the flowability of the influent and at the same time acts as a binder to increase the dry strength of the influent. If the alumina powder is used in less than 5% by weight, the flowability of the inflow material is lowered and the dry strength is lowered. If it exceeds 10% by weight, the liquidity is lowered, the price is also disadvantageous.

On the other hand, in the present invention, 1 to 3% by weight of silica flower powder by extrapolation, 0.1 to 0.4% by weight of sodium hexametaphosphate as a dispersant, and 0.02 to 0.04% by weight of citric acid as a curing retardant are added to the basic composition as described above. It is preferable to form an alumina-spinel-based inflow material, because of the following.

The silica flower is not only to impart fluidity and maintain dry strength in the present invention but also to maintain bonding strength in an intermediate temperature range (600 to 1000 ° C.). If the amount is too small, the addition of too much fluidity is rather inferior in fluidity and creates a low melting point material of alumina-magnesia-silica-based so that the hot strength and corrosion resistance are deteriorated. Therefore, in the present invention, it is preferable to limit the addition amount of the silica flower to 1 to 3% by weight with respect to the basic composition of the refractory composition.

The hexametaphosphate serves as a dispersant in the present invention, and considering the sufficient dispersibility, the addition amount is preferably limited to 0.1 to 0.4% by weight extrapolated to the basic composition. When the addition amount of sodium hexametaphosphate by extrapolation to the basic composition is less than 0.1% by weight, the fluidity of the inflow material is insufficient, and when it exceeds 0.4% by weight, the fluidity and corrosion resistance are rather deteriorated.

The citric acid as the role of the curing retardant in the present invention, in consideration of the working time during the inlet material construction, the addition amount is preferably limited to 0.02 to 0.04% by weight extrapolated to the basic composition. If it is added less than 0.02% by weight, the kneaded material will harden quickly, which may cause trouble in construction work. If it exceeds 0.04% by weight, the flowability of the inflow material will be severely degraded during kneading, making kneading itself difficult.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples.

[Examples 1 to 2] and [Comparative Examples 1 to 9]

To prepare the ladle inflow material using 5.5% of the additive composition as shown in Table 1, the flow value for the evaluation of the workability as the inflow material was measured, and after the test piece was prepared, the bending strength, remaining The rate of line change and the erosion resistance were evaluated and shown in Table 1 below.

At this time, the flow value is 100mm inside the flow cone (flow cone) is placed in the center of the metal plate of the flow meter, the kneaded sample is filled with about 1Kg and then the flow cone is removed. . Due to the up-and-down impact of the disc, the sample on the disc spreads widely according to the size of fluidity. After 15 blows, the longest part and the shortest part of the flowed material were measured and the average value was taken as the flow value. If such a flow value is 150 or more normally, it can be judged that constructability is favorable.

The specimen size for measuring the bending strength and residual line change rate was manufactured at 40mm × 40mm × 160mm, and the specimen for erosion test was 118mm (back side) × 110mm (height) × 40mm (thickness) × 82mm (front side) After injection molding, curing for 24 hours, demolding and drying at 110 ℃ for 24 hours was used for the test.

The erosion depth and the depth of infiltration were measured by cutting the center of the specimen after rotational erosion test at 1650 ~ 1700 ℃ for 4 hours using a ladle slag with basicity (CaO / SiO ₂ ratio) 3.5 and total Fe 17% as an erosion agent. One value.

division Example Comparative example One 2 One 2 3 4 5 6 7 8 9 For steel ladle
Influent
(weight%) Alumina Clinker 70 69 77 70 70 68 70 70 70 70 70 Spinel
(MgAl ₂ O ₄ )
Clinker 20 25 20 18 20 22 20 20 20 20 20 calcination
Alumina powder 10 6 3 12 10 10 - 10 10 10 10 Silica
flower +1 +2 +1 +1 - +4 +1 +1 +1 +1 +1 Alumina
cement - - - - - - 10 - - - - Hexameta
Sodium Phosphate +0.1 +0.1 +0.1 +0.1 +0.1 +0.1 +0.1 +0.1 +0.1 - +0.6 Citric acid +0.02 +0.02 +0.02 +0.02 +0.02 +0.02 +0.02 - +0.05 +0.02 +0.02 % Added 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 Flow rate (mm) 190 180 130 140 190 140 150 180 110 120 140 Quick fixation (hardening degree) Good Good Good Good Good Good Good Quickly - Good - Bending strength
(kg / cm ² ) 110 ℃ × 24h 55 60 30 60 35 65 65 50 45 50 55 1000 ℃ × 3h 70 75 40 80 30 80 80 70 60 60 75 1500 ℃ × 3h 120 110 70 110 90 130 135 120 125 90 130 Residual Line Change Rate
(%) 1500 ℃ × 3h +0.5 +0.4 -0.2 +0.6 +0.6 -0.2 +0.6 +0.5 +0.6 +0.5 +0.2 Spolling Test Results 10 10 10 7 8 8 7 5 6 10 9 Erosion Depth (mm) 8 8 10 12 9 15 17 8 15 10 12 Infiltration depth (mm) 4 5 7 8 8 5 5 5 10 5 5

As can be seen in Table 1, in the case of Examples 1 to 2 satisfying the scope of the present invention, it can be seen that the characteristics of the inflow material is superior to the case of Comparative Examples 1 ?? 9 that do not satisfy the scope of the present invention. have.

On the other hand, Comparative Example 1 is the addition of ultra-fine alumina less than the range of the present invention shows a low dry strength and remaining shrinkage, Comparative Example 2 is the addition of the ultra-fine alumina exceeds the claims, the fluidity of the kneaded product is inferior.                     

In Comparative Example 3 and Comparative Example 4, the addition amount of the silica flower was outside the claims, and when the amount of the silica flower was added less than the claims, the dry strength and the plastic strength at 1000 ° C. were weak. Comparative Example 5 is that the addition of alumina cement not included in the claims as a binder can be seen that the corrosion resistance is significantly reduced. In Comparative Example 6, the kneaded product was rapidly quenched within 10 minutes without adding the curing retardant citric acid. In Comparative Example 7, the flow rate of the kneaded product was significantly lowered because the amount of citric acid exceeded the claims. In Comparative Example 8 and Comparative Example 9, it can be seen that the fluidity is lowered because the amount of added hexamethaphosphate as a dispersant is out of the range of the attached words.

As described above, the refractory composition of the inflow material for steelmaking ladle according to the present invention is for the inflow material of the alumina-spinel system, using alumina powder and silica flower instead of the usual alumina cement as a binder, and as a dispersant and a curing retardant By adding sodium hexametaphosphate and citric acid to prepare a refractory composition of the inlet for steelmaking ladle is a useful invention that has the effect of improving the corrosion resistance and infiltration resistance without deterioration in strength.

While the invention has been described in detail above with reference to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope and spirit of the invention, and such modifications and variations fall within the scope of the appended claims. It is also natural.

Claims (4)

65 to 70 wt% of alumina clinker, 20 to 25 wt% of spinel clinker powder, 5 to 10 wt% of calcined alumina powder, 1 to 3.0 wt% of silica flower powder, 0.1 to 0.4 wt% of hexametaphosphate and 0.02 to 0.04 wt% citric acid Refractory composition of the inlet for steelmaking ladle comprising a%. The method of claim 1, The purity of the alumina clinker is a refractory composition of the inlet for steelmaking ladle, characterized in that the content of alumina (Al ₂ O ₃ ) is 98% or more. The method of claim 1, Particle size of the spinel clinker powder is a refractory composition of the inlet for steelmaking ladle, characterized in that less than 0.074mm. The method of claim 1, The fired composition of the inlet for steelmaking ladle, characterized in that the particle size of the calcined alumina powder is 0.5㎛ or less.