KR100689154B1 - Refractory materials for mgo-c brick - Google Patents

Abstract

A magnesia-carbon material based refractory composition for refractory bricks is provided to show excellent corrosion resistance and oxidation resistance to steel species having high oxygen content and be employed as interior material for furnace parts such converter or ladle by comprising nano-carbon, flake graphite and magnesia clinker as the residue. The refractory composition comprises: 1 to 20wt.% of flake graphite with more than 98% of purity; 1 to 10wt.% of nano-carbon having specific surface area of 5 to 10 times compared to the flake graphite; and magnesia clinker as the residue of the composition, in addition to, liquid and solid phenol resin, metal and inorganic anti-oxidant. The produced composition is used to manufacture a magnesia-carbon based refractory brick which has excellent corrosion resistance and oxidation resistance in case of treating steel species having high oxygen content or non-deoxidized steels and improves durability of furnace parts such as convert or ladle.

Description

Refractory materials for MgO-C brick with excellent corrosion resistance and oxidation resistance

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the comparison result of the Example of this invention, and a comparative example.

The present invention relates to a refractory composition for magnesia-carbon refractory bricks, and more particularly, to be used as an internal refractories for furnaces such as converters or ladles, and has excellent oxidation resistance to steel grades having high oxygen content. A fireproof composition for magnesia-carbon refractory bricks.

Recently, in order to reduce the load on the manufacture of high-grade steel and to reduce the load, external furnace refining such as melting loss, desulfurization, dephosphorization, and desulfurization by lime or soda-based flux injection is actively progressed. Due to the prolonged molten steel retention time and strong stirring, the internal refractories for the ladle are subject to great damage. In particular, MgO-C quality refractory bricks commonly used in the slag line of the ladle are subjected to thermal spalling by rapid quenching, structural spalling by infiltration of slag, and reaction with slag during the introduction and fluxing of the flux. The low melting point compound, the mechanical wear caused by the vortex of molten steel and the oxidation reaction of carbon are severely damaged.

For this reason, in order to improve the corrosion resistance of magnesia-carbon (MgO-C) fire-resistant bricks, in the prior art, spherical graphite with an adjusted aspect ratio (JP 00246272) or pitch-treated mesophase carbon The method of using powder (JP 00342456), etc. has been used.

However, the above-described method of improving the corrosion resistance of the magnesia-carbon refractory brick of the prior art does not effectively inhibit the oxidation of carbon when used in a furnace treating high oxygen steel or mithalated acid steel, and thus the corrosion resistance of the magnesia-carbon refractory brick. This has a problem of sharply lowering. In addition, there is a problem in that the sintering property of the oxide layer produced by the oxidation of carbon is weak, thereby reducing the wear resistance caused by the vortex of molten steel or increasing the infiltration by slag.

Therefore, to solve the problems caused by the use of spherical graphite with an adjusted aspect ratio as described above (JP 00246272) or using mesophase carbon powder heat treated to pitch (JP 00342456). Japanese Patent Laid-Open No. Hei 10-226573 discloses a method of coating a surface of a carbon molded body with a metal organic compound or a metal salt in a liquid state.

However, in this case, there is a problem that the coating layer formed on the surface can be easily damaged with the disadvantage that the raw material is very expensive.

Therefore, the present invention is to solve the above-mentioned problems of the prior art, by improving the oxidation resistance for steel species with high oxygen content to improve the life of the furnace body when used in a furnace such as a converter (Convert) or ladle (Ladle) It is an object of the present invention to provide a magnesia-carbon refractory brick refractory composition having excellent corrosion resistance and oxidation resistance.

The magnesia-carbon refractory brick refractory composition excellent in corrosion resistance and oxidation resistance of the present invention for achieving the above object has 1 to 10% by weight of nano carbon having a specific surface area ratio of 5 to 20 times and 1 to 1 weight of graphite graphite. It is ˜20% by weight and the balance is magnesia clinker, characterized by consisting of liquid and solid phenolic resins and metals and inorganic antioxidants.

In the present invention described above, the type and content of the binder and the antioxidant of the magnesia-carbon refractory brick are not particularly limited and conventional ones may be used.

Although it does not specifically limit as said pulling graphite in this invention, It is preferable that a specific surface area is 0.5 m <^2> / g in consideration of ease of manufacture and dispersibility. In addition, the purity is preferably 98% or more in order to minimize the influence of impurities.

In the present invention, the specific surface area of the nano carbon is preferably 5 to 20 times that of the graphite graphite. This is because when the specific surface area is 5 times or less, aggregates of nano carbon are not dispersed during kneading, causing kneading nonuniformity. In addition, when the specific surface area of the nano-carbon is more than 20 times that of the phosphate graphite, it is necessary to increase the binder by inhaling the binder during kneading.

It is preferable that content of the said nano carbon added to the fireproof composition of this invention is 1-10 weight%. When the content of the nano carbon is 1 to 10% by weight or less, the effective volume occupied by the nano carbon in the magnesia-carbon refractory brick is small so that the effect of improving corrosion resistance is not expressed. In addition, when the content of the nano carbon is 10% by weight or more, corrosion resistance due to the high oxygen molten steel of the magnesia-carbon refractory brick decreases due to the inherent properties of the nano carbon, which are poor in oxidation resistance.

It is preferable that content of the said impression graphite added to the fireproof composition of this invention is 1-20 weight%. When the content of the pulling graphite is 1% by weight or less, the spalling resistance of the magnesia-carbon refractory brick rapidly decreases, causing peeling during use. Moreover, when content of impression graphite becomes 20 weight% or more, corrosion resistance by the high oxygen molten steel of magnesia-carbon refractory brick will fall.

Hereinafter, with reference to the accompanying drawings showing an embodiment of the present invention will be described the present invention in more detail.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the comparison result of the Example of this invention, and a comparative example.

1 to 10% by weight of nano carbon, 1 to 20% by weight of graphite, and the remainder of magnesia clinker with a specific surface area ratio of 5 to 20 times higher than that of the impression graphite shown in FIG. After kneading the refractory composition consisting of antioxidant, it was molded at a pressure of 1600kg / cm ² and dried at 200 ^° C. for 24 hours to prepare a magnesia-carbon refractory brick. The prepared specimens were subjected to a rotary erosion test using high oxygen molten steel as an erosion agent at 1650 ^o C to obtain Examples 1 and 2. Here, Example 1 was prepared by the ratio of the specific surface area (imprinted graphite: nanocarbon) 5, the nanocarbon content 10% by weight, the impression graphite content 1% by weight, and Example 2 was the ratio of the specific surface area (imprinted graphite: nano Carbon) 20, nanocarbon content 1% by weight, and prepared graphite content 20% by weight.

Further, magnesia-carbon refractory bricks were prepared in the range outside the range of the examples of the fireproof composition for the magnesia-carbon refractory bricks of the present invention, and erosion tests were carried out to obtain Comparative Examples 1 to 6.

The composition of the comparative examples is as follows.

Comparative example 1: ratio of specific surface area (impression graphite: nanocarbon) 3, nanocarbon content 5 weight%, impression graphite content 10 weight%.

Comparative Example 2: Ratio of specific surface area (impression graphite: nanocarbon) 25, nanocarbon content 5% by weight, and impression graphite content 10% by weight.

Comparative Example 3: Ratio of specific surface area (impression graphite: nanocarbon) 10, 0.1% by weight of nanocarbon content, 10% by weight of graphite content.

Comparative Example 4: Ratio of specific surface area (imprinted graphite: nanocarbon) 10, nanocarbon content 15% by weight, and impression graphite content 10% by weight.

Comparative Example 5: Ratio of specific surface area (imprinted graphite: nanocarbon) 10, nanocarbon content 7% by weight, and impression graphite content 0.1% by weight.

Comparative Example 6: Ratio of specific surface area (impression graphite: nanocarbon) 10, nanocarbon content 7% by weight, impression graphite content 25% by weight.

1 compares Example 2 with Comparative Examples 1 to 6 when the erosion index of Example 1 is set to 100. In Example 2, the erosion index is 97, and the erosion index of Comparative Example is In each case of Comparative Example 1, cracking occurred during molding due to uneven mixing of clay, Comparative Example 2 was 140, Comparative Example 3 was 120, Comparative Example 4 was 121, and Comparative Example 5 was 115, and cracks were generated in the test specimens after the test. And Comparative Example 6 were found to be 125.

That is, as in the present invention, 1 to 10% by weight of nano carbon and 1 to 20% by weight of impression graphite, and the remainder are magnesia clinker with a specific surface area ratio of 5 to 20 times with the impression graphite, and the balance of the usual liquid and solid phenol resins and metals. And Examples 1 to 2 prepared by the fire-resistant composition for magnesia-carbon refractory bricks composed of an inorganic antioxidant was able to achieve the object of the present invention, Comparative Examples 1 to 6 out of the scope of the present invention to improve the corrosion resistance It can be seen that the effect is weak.

Magnesia-carbon refractory bricks prepared using the above-described magnesia-carbon refractory bricks having excellent corrosion resistance and oxidation resistance have excellent corrosion resistance and oxidation resistance when treating high grade oxygen or oxidized steel. When used in a furnace such as a converter (Convert) or ladle (Ladle) provides an effect to improve the life of the furnace body.

In addition, the present invention described above provides an effect of remarkably improving corrosion resistance and oxidation resistance without using expensive raw materials as in the prior art by using inexpensive raw materials.

Claims (2)

delete Impression graphite whose purity is 98% or more: 1-20 wt%, Nano carbon: 1 to 10% by weight, with a specific surface area ratio of 5 to 20 times with the impression graphite, The remainder is a magnesia clinker, and a magnesia-carbon refractory brick having excellent corrosion resistance and oxidation resistance, comprising a liquid and solid phenol resin, a metal and an inorganic antioxidant.

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