KR101489381B1 - Refractory composition and furnace runner cover of using it - Google Patents

Abstract

The present invention relates to a fire resistant composition and a blast furnace runner cover produced using the same, wherein the fire resistant composition includes a main component including a plurality of components and constituting a basic composition; and a binder for binding the components. The main component includes 70 to 85 wt% of an alumina clinker, 10 to 20 wt% of silicon carbide, and 1 to 3 wt% of a silicon powder. By using the fire resistant composition, a blast furnace runner cover which includes an alumina clinker having an alumina content of 98% or more and has a fire resistant material consisting of alumina-silicon carbide can be produced. When a smelted material is discharged from a blast furnace, the fire resistant material can be prevented from being damaged by FeO included in fly ash and slag (CaO-Al_2O_3-SiO_2-based). Accordingly, the lifespan of the fire resistant material is extended, and the number of repairs needed can be decreased. Also, time and cost spent on repairs can be reduced. Moreover, productivity can be improved by controlling delays in blast furnace work caused by unnecessary repairs.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory composition and a furnace runner cover,

The present invention relates to a refractory composition and a blast furnace cover manufactured using the same, and more particularly, to a refractory composition capable of reducing the influence of a melted matter discharged from a blast furnace and a blast furnace cover will be.

Generally, the blast furnace works by charging raw iron ore and fuel coke into the blast furnace, and blowing high-temperature hot air to burn coke, thereby reducing and melting iron ore to produce molten iron and slag. Then, the generated melts are discharged to the outside through the tapping hole of the blast furnace, and are separated into molten iron and slag by the difference of the specific gravity, and flow to the molten iron bath and the slag bath respectively.

At this time, in order to maintain the temperature of the melt moving through the bath and to increase the safety by suppressing or preventing external scattering of the melt, a cover is arranged on the bath.

The cover is usually made of iron, and a refractory for protecting the iron from the melt is provided between the melt and the iron. Such a cover uses alumina-silica-based refractory materials which are less likely to scatter melt on the cover when a melt is discharged from a small blast furnace, considering thermal insulation and thermal shock resistance.

However, as the blast furnace becomes larger, high-temperature and high-pressure operations are being carried out in the blast furnace, and when the operating environment in the blast furnace is unstable, a splash phenomenon occurs in which the melt is discharged from the blast furnace and falls on the cover. In this case, the melt is a mixture of molten iron (Fe) and slag (CaO-Al ₂ O ₃ -SiO ₂ ), and when the melt is scattered as a cover refractory, the problem of increasing the damage and erosion of the alumina- .

Due to the rapid erosion of these alumina-siliceous materials, the cover refractories are replaced after several use and maintenance, and most of the used alumina-silicalized cover refractories are buried in the landfill. Therefore, the buried waste refractory is often accompanied by environmental pollution problems due to frequent maintenance and maintenance, and the cost of the waste is considerable.

KR 2009-0057807 A1

The present invention provides a refractory composition composed of alumina-silicon carbide and an inflow material for a blast furnace cover, which can improve corrosion resistance and resulfolability due to components of a melt scattered on a hot-rolled coil cover at the time of leaving the melt at a furnace.

The present invention provides a refractory composition and an inflow material for a blast furnace cover which can improve the workability by increasing fluidity.

The present invention provides a refractory composition and an inflow material for a blast furnace cover that can suppress or prevent delays in blast furnace operation and increase the productivity and efficiency of operation.

A refractory composition according to an embodiment of the present invention comprises a main component including a plurality of components and constituting a basic composition and a binder for binding the plurality of components, wherein the main component comprises 70 wt% to 85 wt% of alumina clinker, Silicon carbide: 10 wt% or more to 20 wt% or less, and silicon powder: 1 wt% or more to 3 wt% or less.

The binder may include alumina cement: 3 wt% or more to 5 wt% or less, silica flower: 1 wt% or more to 2 wt% or less, by weight.

The additive may further comprise a dispersant and a curing retarder.

The dispersant may include oxygen, which is hexamer, and the sodium hexametaphosphate may be included in an amount of 0.1 to 0.4 parts by weight based on the total weight of the refractory composition.

The curing retarder may include citric acid, and the citric acid may include 0.02 or more to 0.04 or less of the weight of the total weight of the refractory composition.

The refractory composition may have a fluidity of 160 mm or more, a dry strength of 70 to 90 kg / cm 2, a plasticity strength of 150 to 195 kg / cm 2, and an erosion depth of 2 mm or less.

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

A blast furnace cover according to an embodiment of the present invention includes a steel plate covering the upper portion of the bath and a refractory joined to one side of the iron plate facing the bath, wherein the refractory has a content of alumina of 98 % Alumina clinker, and is formed into an alumina-silicon carbide system.

The refractory may contain, by weight, the alumina clinker in an amount of 70 to 85 wt%.

Wherein the refractory material comprises silicon carbide in an amount of 10 wt% to 20 wt%, silicon powder in an amount of 1 wt% to 3 wt%, alumina cement in an amount of 3 wt% to 5 wt%, silica flower in an amount of 1 wt% to 2 wt% As shown in FIG.

And an oxygen content of 0.1 to less than 0.4 parts by weight based on the total weight of the refractory.

And may further include 0.02 or more to 0.04 or less parts by weight of citric acid based on the total weight of the refractory.

The refractory may have a fluidity of 160 to 170 mm, a dry strength of 70 to 90 kg / cm 2, a plasticity strength of 150 to 195 kg / cm 2, and an erosion depth of 2 mm or less.

According to the refractory composition according to the embodiment of the present invention and the blast furnace cover manufactured using the same, the main component of the refractory composition used in the blast furnace cover is constituted of an alumina-silicon carbide system, and alumina- Lt; / RTI > Accordingly, it is possible to obtain a refractory composition having increased erosion resistance, invasiveness and resulfolability, and it is possible to obtain a refractory composition having a high melting point and a high melting point of FeO and slag (CaO-Al ₂ O ₃ -SiO ₂ system) It is possible to reduce the damage of the refractory caused by the refractory material.

Therefore, it is possible to extend the service life of the cover refractory to reduce the number of times of maintenance, and to save time and cost required for maintenance. In addition, productivity can be improved by suppressing delay in blast furnace operation due to unnecessary maintenance.

It is also possible to reduce the total amount of waste refractories generated when replacing the cover refractory, thereby reducing the environmental pollution that may be caused by the landfill disposal and also reducing the cost of constructing a new refractory.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a general blast furnace part and a hot runner cover. FIG.
Fig. 2 shows constituent components of the refractory composition according to the embodiment of the present invention and the inflow material for a blast furnace cover.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

Prior to the description of the refractory composition according to the embodiment of the present invention, the blast furnace portion and the bath cover in which the refractory composition is used will be briefly described.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a general blast furnace part and a hot runner cover. FIG.

Referring to FIG. 1, iron ore as raw material and coke as fuel are charged into the blast furnace 10 through an inlet of an upper furnace (not shown), and hot air is blown through a tuyere (not shown) It burns coke to make heat and reducing gas. The generated heat and the reducing gas are generated by reducing and melting the iron ores in the blast furnace 10 to generate molten iron and slag and are discharged through the tapping tunnel 15 under the blast furnace 10.

The discharged molten material flows through the molten metal 20, and the molten material flowing into the molten metal 20 is separated into molten metal having a large specific gravity due to the difference in specific gravity and slag having a specific gravity relatively smaller than molten metal. The separated molten iron and slag are separated by a skimmer (not shown) at the rear end of the molten metal 20 and separated into a molten metal bath 20b through which the molten metal flows and a slag molten metal 20a through which the molten metal flows. The molten iron flowing to the molten metal duct 20b is stored in a crosstalk car (not shown) through a racing cylinder (not shown), and is transferred to a steelmaking plant as a post-process.

In the above-described operating process, the blanket 20 is provided with the blanket cover 30 to seal the blanket 20. At this time, the molten metal cover 30 covers the upper part of the molten metal 20, which is discharged from the tapping tunnel 15 of the blast furnace 10, such as molten metal and slag, To protect the peripheral equipment, and to prevent solidification due to cooling of the melt.

The blanket cover 30 covers the upper portion of the blanket 20 and is bonded and disposed on one side of the blanket 31 facing the blanket with the blanket 31 forming the blanket, And a refractory 35 disposed on the inside of the constituent space to protect the iron foil 31 from the hot molten material.

Therefore, the refractory composition according to the embodiment of the present invention is used in the blast furnace cover 30, and is configured to improve the corrosion resistance and the anti-spalling property by the high-temperature melt.

Hereinafter, the refractory composition according to the embodiment of the present invention and the inflow material for a blast furnace cover will be described with reference to Fig.

Fig. 2 shows constituents of the refractory composition according to the embodiment of the present invention.

The refractory composition according to an embodiment of the present invention can be used as an inflow material for a blast furnace cover in manufacturing a cover for blast furnace blast furnace which seals the blast furnace blast furnace. That is, the refractory composition is composed of refractory components, and therefore, the blast furnace cover is composed of alumina (Al ₂ O ₃ ) -silicon carbide (SiC) system including alumina clinker having an alumina content of 98% The erosion property can be improved.

That is, the refractory composition comprises a main component containing a plurality of components and constituting a basic composition, and a binder binding the plurality of components, wherein the main component is 70 wt% or more to 85 wt% or less of alumina clinker, Silicon carbide) of not less than 10 wt% and not more than 20 wt%, and silicon powder (Si powder) of not less than 1 wt% and not more than 3 wt%. In addition, the binder may be composed of not less than 3 wt% and not more than 5 wt% of alumina cement, and not less than 1 wt% and not more than 2 wt% of silica flour as alumina cement.

Thus, in the present invention, the refractory composition can be used for making a blast furnace cover, so that the refractory composition and the blast furnace cover can be the same or similar. Therefore, in the following, the refractory composition and the blast furnace can be used in the same way as the cover material for the cover.

Here, the inclusion of the above-mentioned components includes elements (main component, binder, dispersant) constituting one constituent (refractory composition), and it has the same meaning as that composed of a plurality of components contained in the refractory composition .

In general, the conventional alumina-silica refractory composition is vulnerable to thermal shock, and is easily infiltrated into the load in the presence of surface cracks and inclusions, and the surface is gradually peeled off, that is, structural spalling is apt to occur. In the present invention, in order to reinforce this disadvantage then exclude possible to SiO ₂ of conventional construction, fire-resistant, which, by combining a material capable of increasing the corrosion resistance can improve the abrasion resistance and Nass polling property by reducing reaction of FeO composition And a blast furnace cover manufactured through the same.

Each component included in the refractory composition according to an embodiment of the present invention is shown in Table 1 below.

ingredient Content (% by weight)
chief ingredient Alumina clinker 70 ~ 85 Silicon carbide 10-20 Silicon powder 1-3 Binder Alumina cement 3 to 5 Silica flower 1-2 additive Dispersant (sodium hexametaphosphate) 0.1 to 0.4 Curing retarder (citric acid) 0.02 to 0.04

The main component contains a plurality of components of the refractory composition and forms the basic composition, and the main component may include alumina clinker, silicon carbide, and silicon powder. That is, the main component is a component constituting at least 80% by weight based on 100% by weight of the refractory composition.

Further, the binder is contained in an amount lower than the content of the main component based on 100 wt% of the refractory composition, and may be included in the refractory composition to bond the plurality of components of the main component to each other. At this time, the binder may include alumina cement and silica flower.

[Alumina clinker]: 70 to 85 wt%

Alumina clinker is a refractory material that improves the corrosion resistance to slag and charcoal, and the content of alumina (Al ₂ O ₃ ) is 98% or more. That is, a material containing a large amount of alumina may be used in order to obtain corrosion resistance against FeO among the scattered materials. Accordingly, the alumina clinker may use at least one of sintered alumina clinker and fused alumina clinker. However, a fused alumina clinker can be used to achieve high corrosion resistance.

At this time, the alumina clinker may be contained in the refractory composition in an amount of 70 wt% or more to 85 wt% or less. When the content of alumina clinker is less than 70 wt%, the corrosion resistance is deteriorated. When the content of alumina clinker is more than 85 wt%, thermal shock resistance may be deteriorated. The content of the alumina clinker may be used to improve the corrosion resistance and wear resistance of the refractory aggregate except for the silicon carbide, silicon powder, and alumina cement and ultrafine powder silica as binders.

[Silicon carbide]: 10 to 20 wt%

Silicon carbide (SiC) is used for improving corrosion resistance of molten iron and slag as well as abrasion resistance of refractories. The content of silicon carbide (SiC) in the refractory composition may be 10 wt% or more and 20 wt% or less. If the content of silicon carbide is less than 10 wt%, the corrosion resistance and thermal shock resistance are deteriorated. If the silicon carbide content exceeds 20 wt%, excessive corrosion resistance is deteriorated. In addition, due to the high thermal conductivity, the heat insulating property is deteriorated and the iron foil can be deteriorated. Therefore, silicon carbide can be included in the above range of contents.

[Silicon powder]: 1 to 3 wt%

Silicon powder (Si powder) is used to increase the strength of the surface portion of the refractory composition introduced into the refractory composition by reacting with oxygen or nitrogen in the air. The refractory composition may have a content of 1 wt% or more to 3 wt% or less. If the content of the silicon powder is less than 1 wt%, the strength of the refractory is not improved. If the content is more than 3 wt%, the workability of the inflow material may be deteriorated. Thus, the silicon powder may include the above-mentioned range of contents.

[Alumina Cement]: 3 to 5 wt%

Alumina cement is used to improve the strength and corrosion resistance of refractories. Generally, cement (cement) is prepared by mixing bauxite (Al ₂ O ₃ .H ₂ O) and limestone (CaCO ₃ ) to be. At this time, in the embodiment of the present invention, alumina cement having a CaO content of about 30 wt% can be used. The alumina cement can increase the stiffness and fire resistance, and the content of the refractory composition may be 3 wt% or more to 5 wt% or less. If the content of alumina cement is less than 3 wt%, the curing action is weak and the bonding strength is lowered. If the content is more than 5 wt%, the corrosion resistance and the hot strength may be lowered. Thus, the alumina cement may include the above range of contents.

[Silica flower]: 1 to 2 wt%

Silica flour is used to improve the workability and strength of the inflow material. It is also called a fine powder (silica sand powder) which is generally crushed into silica, and its particle size is usually 80 to 325 mesh. The silica flower contains 99.5% of silica and can improve the high temperature strength, and the content of the refractory composition may be 1 wt% or more to 2 wt% or less. If the content of the silica flower is less than 1 wt%, the effect of improving the workability and strength is insufficient, and if it exceeds 2 wt%, the workability may be lowered. Thus, the silica flower may include the above range of contents.

In addition to the main components and binders shown in Table 1, a dispersant and a curing retardant may be added as additives to increase the workability of the inflow material composed of the additives to increase the workability of the refractory composition.

[Dispersant, sodium hexametaphosphate]: 0.1 to 0.4 parts by weight

Sodium Hexa Metha Phosphate (SHMP) generally has the properties of sequestration ability, buffering action, dispersing action and washing action, and has the broadest application among phosphates. In the embodiment of the present invention, sodium hexametaphosphate ((NaPO ₃ ) _n P ₂ O ₅ ) serves as a dispersing agent, and may include not less than 0.1 to not more than 0.4 parts by weight based on the total weight of the above-mentioned refractory composition. At this time, if the content of the sodium hexametaphosphate is out of the range of not less than 0.1 and not more than 0.4 parts by weight, the flowability of the inflow material is lowered and the dispersing effect is insufficient and the corrosion resistance may be lowered. Therefore, the content of the above range may be included in the sodium hexametaphosphate.

[Curing retarder, citric acid]: 0.02 to 0.04 part by weight

Citric acid is added in order to knead the refractory composition and to prevent the phenomenon of sharpening at the time of construction. That is, citric acid can be used as a hardening retarder added to slow the condensation of refractory such as cement. The citric acid may include 0.02 or more to 0.04 or less of the weight of the total weight of the above-described refractory composition. If the content of citric acid is less than 0.02 parts by weight, the curing time of the kneaded product is shortened and the effect of delaying curing is not effective, so that the construction is not easy. If the content is less than 0.04 parts by weight, the flowability of the inflow material is inhibited. Therefore, the content of citric acid may be included in the above range.

Hereinafter, experimental results for confirming whether a refractory composition according to an embodiment of the present invention is suitable as a refractory of a cover having a high-temperature process environment will be described in detail with reference to examples and comparative examples.

A refractory composition as shown in Table 2 below was prepared. Thereafter, 6.0% of the total weight of the respective refractory compositions was added, and the specimens were subjected to molding, curing and drying to prepare specimens. At this time, the molding was performed by inflow molding, curing was carried out for 24 hours, and drying was performed at 110 ° C for 24 hours.

Typical physical properties in evaluating the characteristics of the refractory composition are the fluidity to evaluate the workability when the refractory composition is applied to the bath cover and the bending strength, the thermal shock resistance, the heat insulation and the erosion resistance which can evaluate the abrasion resistance to withstand high temperatures.

A flowability evaluation test was conducted to evaluate the workability of the refractory using the specimens thus produced. The flowability test was performed by placing a flow cone having an inner diameter of 100 mm on the center of a metal plate of a flow meter, filling about 1 kg of the kneaded sample, removing the flow cone, leaving only the mass sample, Shock. At this time, the sample on the disk spreads widely by the vertical impact according to the magnitude of fluidity, and the average value after measuring the longest portion and the shortest portion of the flowing material after 15 strokes was flowed. Generally, when the degree of flow is 140 or more, it can be judged that the construction is good.

On the other hand, a test was conducted to measure the bending strength for evaluation of wear resistance. The bending strength evaluation test was conducted on the dry strength (bending strength at 110 DEG C) and the bending strength (bending strength at 1500 DEG C). Specimens for the measurement of bending strength were prepared in a size of 40 × 40 × 160 mm.

In order to confirm the degree of corrosion resistance of the refractory composition, an erosion test and an infiltration test were carried out. The erosion test is carried out by the rotary erosion test method, and materials (molten iron and molten blast furnace slag) that are scattered when the erosion agent leaves the blast furnace can be used. After immersing the sample for erosion test (transverse type, 118 (rear side) × 110 (height) × 40 (thickness) × 82 mm (front side)) in the melt, the sample was subjected to rotary erosion test at 1550 ° C. for 30 minutes. It is measured by cutting the center.

In addition, a thermal shock resistance test of the above specimens was carried out. The resistance to thermal shock was evaluated by evaluating the degree of cracking (○ / X) after holding the resistance to thermal shock for 30 minutes at 1350 ° C for 30 minutes and then cooling it at room temperature for 5 times.

The thermal conductivity of the test specimens was measured and compared with that of the specimens.

division Example Comparative Example One 2 3 4 5 6 One 2 3 4

of mine
anger
article
castle
water
(medium
Amount
%)
Alumina
Clinker 70 85 85 85 70 85 - - 65 90 Bauxite
Clinker - - - - - - 70 - - - MgO clinker - - - - - - - 70 - - Silicon carbide
(SiC) 20 10 10 10 20 10 20 20 25 5 Silicon powder
(Sipowder) 3 One 3 One 5 2 3 3 3 One Alumina
cement 5 3 2 One 3 2 5 5 5 3 Silica flower 2 One 0 3 2 One 2 2 2 One Sodium hexametaphosphate +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 Water added (%) (6.0) (6.0) (6.0) (6.0) (6.0) (6.0) (6.0) (6.0) (6.0) (6.0) Flow (mm) 160 170 130 120 135 150 150 150 140 160 Ruggedness
(Kg / cm2) 110 ° C ×
24hr 90 70 50 50 60 40 80 80 80 85 1500 ℃
× 3 hr 195 150 60 90 120 70 150 140 150 110 Thermal shock resistance
(O / X) ○ ○ ○ ○ ○ ○ ○ X ○ X Insulation (○ / X) ○ ○ ○ ○ ○ ○ ○ ○ X ○ Erosion depth (mm) 2 2 5 8 10 12 38 2 4 2 Depth of penetration (mm) One One One One 3 One One 10 One One

Here, in Examples 1 to 6 of Table 2, materials constituting the refractory composition proposed by the present invention are included. That is, it is composed of a main component composed of alumina clinker, silicon carbide, and silicon powder, a binder including alumina cement and silica flower contained in the main component, and an additive included in parts by weight based on the sum of the main component and the binder. On the other hand, Comparative Example 1 and Comparative Example 2 are examples in which the alumina clinker included in the refractory composition proposed in the present invention is not used. That is, in Comparative Example 1, Bauxite Clinker, which is an alumina raw material, was used instead of alumina clinker, and Magnesia Clinker was used in Comparative Example 2 in place of alumina clinker.

[Example 1]

Example 1 consisted of the contents of the refractory composition within the ranges given in Table 2. That is, the main component and the binder constituting the present invention are included in the present invention, and ranges within the content ranges of the main component and the binder shown in Table 1 are included. When such a content is included, it can be confirmed that the fluidity of the refractory composition is 160 mm and the bending strength has a dry strength of 90 kg / cm 2 and a plasticity strength of 195 kg / cm 2. In addition, it is confirmed that the heat resistant property does not cause cracking, the heat insulation property is good, the erosion depth and the depth of penetration are low, and thus the refractory composition has excellent characteristics.

[Example 2]

In Example 2, as in Example 1, the main components and the materials constituting the binder and the content ranges thereof were composed of the materials and the content ranges proposed in the present invention. At this time, the fluidity of the refractory composition of Example 2 was 170 mm, and it was confirmed that the bending strength had a dry strength of 70 kg / cm 2 and a plasticity strength of 150 kg / cm 2. In addition, it is confirmed that the heat resistant property does not cause cracking, the heat insulation property is good, the erosion depth and the depth of penetration are low, and thus the refractory composition has excellent characteristics.

[Examples 3 to 6]

In Examples 3 and 4, the content of the alumina cement and the amount of the silica flower, which are binders, are out of the content range of the alumina cement and the silica flower proposed in the present invention and have a fluidity of 120 to 130 mm, Cm < 2 > and a plasticity strength of 60 to 90 kg / cm < 2 >. As a result, the fluidity and bending strength were lowered than those of Examples 1 and 2, and the workability and corrosion resistance were reduced. Thus, it can be seen that the erosion depth has an increased value as compared with Examples 1 and 2.

In Example 5, it is confirmed that the silicon powder contained in the silicon powder exceeds the content range of the silicon powder proposed in the present invention and exhibits a fluidity of 135 mm and the workability is lowered. Further, it can be confirmed that the corrosion resistance is lowered.

In Example 6, the content of the alumina cement as a binder is less than the content of the alumina cement proposed in the present invention, so that the dry strength is 40 kg / cm 2 and the plastic strength is 70 kg / cm 2, The corrosion resistance is reduced.

[Comparative Example 1 and Comparative Example 2]

In Comparative Example 1, as shown in Table 2, a bauxite clinker was used instead of alumina clinker. That is, Comparative Example 1 is different from Example 1 in that a bauxite clinker is contained in place of the alumina clinker, and the rest of the constitution is the same as that of Embodiment 1. At this time, in Comparative Example 1, it was found that SiO2 contained in the bauxite clinker reacted with FeO to form a low melting point material having a melting temperature of about 1200 ° C, and the corrosion resistance was remarkably lowered due to the problem of accelerated erosion. As a result, the erosion depth is 38 mm, which means that the erosion depth is larger than that of the first embodiment, and the corrosion resistance is lowered.

In Comparative Example 2, as shown in Table 2, a magnesia clinker was used in place of the alumina clinker. That is, Comparative Example 2 is different from Example 1 in that magnesia clinker is contained in place of alumina clinker, and the rest of the constitution is the same as that of Embodiment 1. In this case, the refractory made of Comparative Example 2 has excellent corrosion resistance to non-product, which is similar to that of Example 1 because the depth of erosion is 2 mm, but it can be confirmed that the thermal shock resistance is improved. Therefore, in the case of producing the hot-dip galvanized refractory with the composition of Comparative Example 2, thermal deformation of the iron constituting the hot dip galvanized steel sheet may be caused to open the thermal shock resistance.

[Comparative Example 3 and Comparative Example 4]

In Comparative Example 3 and Comparative Example 4, the content of alumina clinker and silicon carbide exceeded the content range of the alumina clinker and silicon carbide proposed in the present invention, so that the corrosion resistance was poor and the heat insulating property was not good.

That is, in Comparative Example 3, since the content of silicon carbide exceeds the range of the content of the proposal, an excessive amount of the silicon carbide is contained, which may cause deterioration of the heat insulating property due to increase of the thermal conductivity, and may cause damage to the iron. In addition, in Comparative Example 4, the content of silicon carbide was contained so as to be less than the proposed content range, so that it was confirmed that the resistance to thermal shock was not good and the anti-scrubbing property was reduced. As described above, Comparative Example 3 and Comparative Example 4 improved erosion resistance by using alumina clinker different from Comparative Examples 1 and 2, but the content of alumina clinker and / or the content of silicon carbide deviated from the proposed range of the present invention, In case of Example 3, if the thermal conductivity is high and the heat radiation through the cover of the cover is high, the temperature of the molten iron is lowered, which is not preferable. In addition, in the case of Comparative Example 4, the amount of silicon carbide was insufficient, and it was confirmed that cracks occurred due to low thermal shock resistance.

Examples 1 and 2, which satisfy the content range of the proposed material and the proposed material of the present invention, are suitable for use as an inflow material for a cover for a blast furnace, and in Examples 3 to 6, Example 6 is suitable for use as a refractory for a blast furnace cover as compared to Examples 1 and 2 because at least one of the properties of the refractories shown in Table 2 has low properties for Examples 1 and 2 I can confirm that I did not.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

10: Blast Furnace 15: Outpost
20: Tangdo 20a: Yongseonbangdo
20b: slag bath 30: cover
35: Cover refractory

Claims (13)

A refractory composition for use as an inflow material for a blast furnace cover,
Alumina clinker having a content of alumina of 98% or more by weight based on 100% by weight of the refractory composition: 70 wt% or more to 85 wt% or less, silicon carbide: 10 wt% or more to 20 wt% or less, silicon powder: 1 wt% 3 wt% or less and having a basic composition; And
And a binder including not less than 3 wt% and not more than 5 wt% of alumina cement and not more than 2 wt% of a silica flower, based on 100 wt% of the refractory composition and,
Wherein the refractory composition has a fluidity of 160 mm or more, a dry strength of 70 to 90 kg / cm 2, a plasticity strength of 150 to 195 kg / cm 2, and an erosion depth of 2 mm or less. delete The method according to claim 1,
A refractory composition further comprising a dispersant and a hardening retarder as additives. The method of claim 3,
Wherein the dispersing agent comprises oxygen, which is hexametetra,
Wherein the sodium hexametaphosphate is present in an amount of 0.1 to 0.4 parts by weight based on the total weight of the refractory composition. The method of claim 3,
Wherein the curing retarder comprises citric acid,
Wherein the citric acid comprises 0.02 or more to 0.04 or less by weight of the total weight of the refractory composition. delete delete As a blast furnace cover,
A scoop covering an upper portion of the bath,
And a refractory joined to one side of the iron plate facing the bath,
Wherein the refractory comprises at least 70 wt% to 85 wt% of alumina clinker having an alumina content of 98% or more, silicon carbide: 10 wt% to 20 wt%, silicon powder: 1 wt% to 3 wt% A dry strength of 70 to 90 kg / cm 2, a plasticity of 150 to 195 kg / cm 2, and a flowability of 150 to 150 kg / cm 2, It covers the blast furnace with erosion depth of less than 2mm. delete delete The method of claim 8,
Further comprising an oxygen content of 0.1 to less than 0.4 parts by weight relative to the total weight of the refractory. The method of claim 8,
Further comprising citric acid in an amount of 0.02 or more to 0.04 or less based on the total weight of the refractory. delete

Images