KR100433247B1 - Coating composite of internal wall of converter and its preparations method - Google Patents

Abstract

Refractory converter inner wall coating material composition according to the present invention comprises 95% to 97% by weight of high purity magnesium oxide (MgO) 40% to 85% by weight; 10 weight percent-35 weight percent of high purity calcium carbonate, containing 95 weight percent-98 weight percent calcium carbonate (CaCO ₃ ); And 5% to 25% by weight of carbon (C).

In addition, the method for producing a fireproof converter inner wall coating composition according to the present invention is 40% to 85% by weight, 95% to 98% by weight of high purity magnesium oxide containing 95% by weight to 97% by weight of magnesium oxide (MgO) Mixing and crushing the mixture composed of 10% by weight to 35% by weight of high purity calcium carbonate containing calcium carbonate (CaCO ₃ ) and 5% by weight to 25% by weight of carbon (C), water and adhesive were added to the crushed mixture. This is followed by kneading it, shaping the kneaded mixture with moisture and adhesive, and naturally drying the shaped mixture.

Therefore, the present invention can coat the inner wall of the converter with a coating material composed of high purity magnesium oxide, high purity calcium carbonate and carbon having good corrosion resistance, so that the number of times of use of the converter can be extended to thousands of charges, thereby improving productivity. In addition, it is superior to the conventional coating material in economical efficiency, and since the coating material contains the same components as the components of the converter inner wall, the affinity with the converter inner wall is increased and the adhesion efficiency is increased.

Description

Fireproof converter inner wall coating material composition and its manufacturing method {COATING COMPOSITE OF INTERNAL WALL OF CONVERTER AND ITS PREPARATIONS METHOD}

The present invention relates to a coating material composition used for the inner wall of the converter (reverter) for refining, and to a method of manufacturing the same, and more particularly to a fireproof converter inner wall coating material composition and a method for manufacturing the same that can easily extend the inner wall life of the converter. will be.

For example, the converter method blows and removes carbon (C) by blowing high-pressure air, that is, oxygen (O ₂ ) into the molten steel, and removes phosphorous and sulfur, which are harmful components in the molten metal, as well as controls steel components to clean steel. To produce.

The inner wall of the conventional converter is constructed of Dolomite Brick, which is weak to oxidation erosion, and when using the converter constructed of such dolomite brick, it can use only a few hundred charges (Charge: number of converters). It has caused huge obstacles to productivity.

Therefore, in order to solve the above problems, in recent years, by using the magnesium oxide-carbon brick (MgO-C Brick), that is, magnesia brick, which has stronger oxidation erosion than the dolomite brick, the number of times of use of the converter is over 1000 charges. Extended.

However, since the magnesia brick also blows oxygen, there is a limit to extending the service life of the converter to thousands of charges depending on its non-wetting property, which is its physical property.

In order to solve the above problems, there has been applied for the converter wall coating composition for the refractory to the applicant No. 10-2001-60888.

That is, the fireproof converter inner wall coating composition is heat-treated at 900 ℃-1200 ℃ heat pyrolysis of carbon dioxide (CO ₂ ) to obtain a material adjusted to 95.33% by weight (wt%)-96.86% by weight of magnesium oxide (MgO). 85% by weight to 90% by weight of high-purity magnesium oxide (MgO) obtained by thermal decomposition of CO ₂ from magnesiumsite containing magnesium carbonate (MgCO ₃ ), and 92.05% by weight to 95.51 when thermal decomposition of CO ₂ by thermal treatment at 900 ° C to 1200 ° C. It is made by mixing 10% to 15% by weight of limestone containing calcium carbonate (CaCO ₃ ) to obtain a material adjusted to weight% calcium oxide (CaO).

Conventional coating composition as described above is a magnesite containing MgCO ₃ 900 ℃ - by heat treatment at 1200 ℃ by thermal decomposition of CO ₂ remaining high-purity MgO 85 wt% to 90 wt%, and the limestone 10% by weight, containing CaCO ₃ - 15% by weight of mixed crushed, water and adhesive is added to the crushed crushed, and then mixed and kneaded, and the mixed mixture is molded to convey the molded product in the molding process, it is naturally dried.

However, since the conventional coating material filed by the applicant is composed of a mixture of high-purity MgO and limestone, there is a difference between the inner wall and the components of the magnesium oxide-carbon brick (MgO-C Brick), so the affinity of the inner wall of the converter is not excellent. There is a disadvantage in that the time and efficiency of attachment to the deterioration.

Also, conventionally, high pressure air, ie, oxygen (O ₂ ) is blown into the converter to remove phosphorous and sulfur, which are harmful components in the molten metal, and to control carbon in the molten metal. However, oxygen is a component of the inner wall of the converter. There is a disadvantage that carbon may be removed to promote erosion of the inner wall of the converter.

The present invention has been made to solve the above problems of the prior art, an object of the present invention is to add a certain amount of light magnesium in converter steelmaking to adjust the basicity of the slag, while the magnesium oxide component of the converter inner wall due to the slag By minimizing erosion to protect the inner wall of the converter and increasing the affinity with the inner wall of the converter, to increase the coating efficiency and to easily extend the service life of the converter for providing a fireproof inner wall coating material composition and its manufacturing method There is.

In order to realize this, the present invention, in the composition of the coating material for coating the inner wall of the refractory converter, 40 weight of high purity magnesium oxide containing 95% by weight (wt%)-97% by weight (wt%) of magnesium oxide (MgO) %-85% by weight; 10 weight percent-35 weight percent of high purity calcium carbonate, containing 95 weight percent-98 weight percent calcium carbonate (CaCO ₃ ); And it provides a fireproof converter inner wall coating composition consisting of 5% by weight to 25% by weight of carbon (C).

In addition, the present invention in the manufacture of a coating material for coating the inner wall of the fire-resistant converter, 40 wt%-85 wt%, 95 wt%-98 wt% of high purity magnesium oxide containing 95 wt%-97 wt% magnesium oxide (MgO) Mix and crush the mixture consisting of 10% to 35% by weight of high purity calcium carbonate with% calcium carbonate (CaCO ₃ ) and 5% to 25% by weight of carbon (C), and the water and adhesive Provided is a method for producing a fireproof converter inner wall coating composition comprising mixing and kneading the mixture, forming a mixture kneaded with water and an adhesive, and naturally drying the molded mixture.

1 is a process chart showing a method for producing a coating material composition of an inner wall of a converter for fire resistance according to the present invention;

Figure 2 is a process chart showing a coating method of the inner wall of the converter using the coating material composition according to the present invention.

<Code Description of Main Parts of Drawing>

1: converter 2: scrap

3: metal 3a: slag

4: lance 10: coating material

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the converter inner wall coating material composition and a method for producing the fireproof converter according to the present invention will be described in more detail.

First, the present invention will be described for the coating material composition of the inner wall of the converter for extending the life of the converter.

Refractory converter inner wall coating material composition according to the present invention is composed of 40% by weight-85% by weight of high purity magnesium oxide, 10% by weight-35% by weight of high purity calcium carbonate, 5% by weight-25% by weight of carbon (C).

Here, high purity magnesium oxide (MgO) contains 95% by weight to 97% by weight of magnesium oxide (MgO), and as an example, magnesiumite containing magnesium carbonate (MgCO ₃ ) is heat-treated at 900 ℃-1200 ℃ carbon dioxide ( Pyrolysis of CO ₂ ) results in 95.33% by weight to 96.86% by weight of MgO.

In other words, magnesite containing MgCO ₃ is 40.0 wt%-50.0 wt% MgO, 0.25 wt%-0.35 wt% SiO ₂ , 0.05 wt%-0.1 wt% Al ₂ O ₃ , 1.0 wt%-2.0 wt% CaO In addition to the composition, the remaining CO ₂ is bonded to MgO and CaO to form a salt state such as MgCO ₃ and CaCO _3. When thermally decomposing CO ₂ by heat treatment, MgO 95.33 wt%-96.86 wt%, SiO ₂ 0.60 wt%-0.67 wt% A high purity magnesium oxide consisting of%, Al ₂ O ₃ 0.12%-0.19% by weight and CaO 2.42%-3.81% by weight is produced.

The high purity calcium carbonate (CaCO ₃ ) contains 95% by weight to 98% by weight of calcium carbonate (CaCO ₃ ), for example, using limestone containing CaCO ₃ as it is, limestone is 900 ℃-1200 ℃ When thermally decomposed and thermally decomposed CO ₂ is CaO content of 92.05% by weight-95.51% by weight.

That is, the limestone containing CaCO ₃ is 50.0% to 55.0% by weight of CaO, 1.0% to 1.5% by weight of SiO ₂ , 0.25% to 0.75% by weight of Al ₂ O ₃ , 1.0% to 2.0% by weight of MgO, Fe ₂ O _{3 It} is composed of 0.1% by weight to 0.5% by weight, and the remaining CO ₂ is bonded to CaO and MgO to form a salt state such as CaCO ₃ and MgCO ₃ .

When the limestone is heat-treated, CO ₂ is pyrolyzed, 92.05 wt%-95.51 wt% CaO, 1.91 wt%-2.51 wt% SiO ₂ , 0.48 wt%-1.26 wt% Al ₂ O ₃ , 1.91 wt%-3.34 wt% And high purity calcium oxide (CaO) consisting of a composition ratio of 0.19% by weight to 0.84% by weight of Fe ₂ O ₃ is produced.

It is apparent that the carbon may be an amorphous carbon obtained by removing hydrogen by thermal decomposition of graphite, hydrocarbons such as anthracite coal, and the like.

The method for producing a coating material using the composition thus prepared is as follows.

As shown in FIG. 1, the magnesite containing MgCO ₃ is heat-treated at 900 ° C. to 1200 ° C. to thermally decompose CO ₂ to 40 wt% -85 wt% of high purity magnesium oxide, and 10 wt% of high purity calcium carbonate. -35% by weight, 5% by weight of carbon (C)-25% by weight, mixed and crushed as it is, mixed with moisture and adhesive, and then molded into a small size shape, which is dried to form a coating material, crushed In addition to being able to commercialize the crushed product, it is possible to commercialize a dry coating material.

That is, the mixture of 40% by weight-85% by weight of high purity magnesium oxide, 10% by weight-35% by weight of high purity calcium carbonate, 5% by weight-25% by weight of carbon (C) is crushed by using a crusher, The particle size of the mixture is crushed into 90 mesh-130 mesh.

Water and an adhesive are added to the crushed mixture as described above, and the mixture is mixed with a blender, so that 15% by weight to 25% by weight of water and the adhesive are added to impart moldability to the mixture.

In addition, the mixture of the moisture and the adhesive is molded into a mold, and the mold is preferably molded into a mold with an average particle diameter of 30 mm to 60 mm, and the molded product may be formed into a spherical shape or almond.

The molding, which is a mixture molded into a mold as described above, is transferred to a drying plant by a belt conveyor or the like and naturally dried. The molding is dried at a room temperature of 20 ° C.-30 ° C., and the molding is dried for 24 hours. This is preferred.

The high-purity magnesium oxide obtained by heat-treating magnesite containing MgCO ₃ maintains the high viscosity of the slag and maintains the saturated state of the MgO component in the slag to prevent erosion by infiltration.

Thus, mixing 40% by weight to 85% by weight of the high purity magnesium oxide increases the affinity with the inner wall of the converter together with carbon while maintaining the high viscosity of the slag, and 40% by weight to 85% by weight of high purity magnesium oxide (C) When it is out of the range of 5 weight%-25 weight%, it becomes difficult to maintain the viscosity of slag and to maintain the saturated state of the magnesium oxide component in slag, and it cannot become effective synergistic effect on affinity of converter inner wall.

Of course, when the MgO contained in the high-purity magnesium oxide used in the present invention is less than or exceeds 95% by weight to 97% by weight, the viscosity of the slag and the saturation of the MgO component in the slag may not be maintained, preventing erosion. .

And limestone containing CaCO ₃ is converted to high purity calcium oxide as CO ₂ is thermally decomposed during the coating method described below, and this high purity calcium oxide is mixed with the high purity magnesium oxide to maintain the fluidity of the slag and saturate the MgO component in the slag. It serves to prevent erosion by infiltration due to state maintenance.

In addition, the high-purity calcium carbonate bursts the dried molded product during pyrolysis. If the content is less than 10% by weight, the amount of carbon dioxide generated by the thermal decomposition is small, so that the burst of the molded product is less likely to occur. There is a lot of heat absorbed during the process, so that it is not possible to promote the decomposition of all moldings.

Of course, when CaCO ₃ contained in the high purity calcium oxide used in the present invention is less than or exceeds 95% by weight to 98% by weight, the function of preventing erosion by infiltration due to maintaining fluidity of the slag and maintaining the saturated state of MgO component in the slag Will not be able to perform

Furthermore, the carbon may contain 5% by weight to 25% by weight to improve affinity with the magnesia (MgO-C) constituting the converter inner wall, thereby improving the adhesion of the coating material to the converter inner wall.

In other words, if the carbon content is less than 5% by weight, the ratio of carbon constituting the converter's inner wall becomes smaller than that of the carbon erosion of the converter's inner wall. It may interfere with refining operations, ie, control of the carbon content of the metal.

Meanwhile, in the present invention, the high-purity magnesium oxide, high-purity calcium carbonate, and carbon are shredded into 90 mesh-130 mesh, and when the particle size is larger than the above range, the moldability is not good and the adhesive force is easily degraded. If the particle size is smaller than the above range, it is scattered and is difficult to handle.

Of course, the mixture may be shredded to a size of 90 mesh to 130 mesh, then packaged and stored as it is, or sold in the packaged state.

In order to impart moldability to the mixture, it is kneaded after adding water and an adhesive, wherein the addition ratio of the water and the adhesive is 15% by weight to 25% by weight of the total weight of the mixture.

If the moisture and the adhesive is less than 15% by weight, the moldability is not good and the molding cannot be easily performed. If the moisture and the adhesive are more than 25% by weight, the molding becomes difficult to handle even if the molding becomes too high.

It is preferable to use a water-soluble adhesive, and the adhesive may be blended in the same amount of water and the adhesive, it is preferable to minimize the mixing ratio of the adhesive.

The average particle diameter of the molding is 30mm-60mm to facilitate handling, and the reason for making the coating material into a spherical shape or almond shape is easy to handle, less friction between the coating materials and the contact area when coating the converter inner wall. To make a lot more.

Thus is prepared a coating material for coating the converter inner wall kept by the packing of the coating material prepared by a process as described above or is the sale, the coating material is 10Kg / cm ² - to hold the 20Kg / cm ² compressive strength do.

Meanwhile, the inner wall of the converter is coated with the coating material of the present invention, and the coating method of the inner wall of the converter using the inner wall coating material for the converter according to the present invention is as follows.

That is, the coating method of the present invention, as shown in Figure 2, inclined the converter (1) inclined in order to refine the molten metal, scrap (2), such as scrap metal, scrap, etc., usually in about 15% by weight Then, the waste water 3 is introduced from the upper portion of the scrap 2, although not shown, the lance 4 is introduced to blow oxygen to burn impurities in the waste water 3, and then the lance 4 is removed. .

Then, the inner edge portion of the converter (1) is broken by the scrap (2), the slag (3a) is suspended in the upper portion of the water (3) in the converter (1), due to the slag (3a) The inner wall of the converter 1 is eroded.

In this state, the converter 1 is laid on its side, and the sludge 3 flows out through the tapping hole, and the slag 3a remains in the converter 1 from which the sludge 3 has flowed out, and such slag 3a is left. ) Put the coating material 10 of the present invention on.

At this time, the slag (3a) is a flowable solid and is cooled while being mixed with the coating material 10, or even when blowing the nitrogen by the lance (4).

In any case, the lance 4 is injected into the converter 1 to inject nitrogen at a high pressure. At this time, the slag 3a and the coating material 10, which are fluid solids, are mixed with each other and splashed on the inner wall of the converter 1.

At this time, since the coating material 10 flows together with the slag 3a while the temperature inside the converter 1 is 900 ° C. to 1200 ° C., some are attached to the inside of the converter 1 but the other part is along the inner wall of the converter 1. As it flows down, the carbon contained in the coating material 10 burns and the high-purity calcium carbonate is thermally decomposed to generate carbon dioxide. At the same time, the coating material 10 bursts due to the carbon dioxide.

And a coating material 10 as in the converter (1) the inner wall of the back coating together with the slag (3a), the coating material 10 or 10Kg of nitrogen to the lance 4 to inject limestone back / cm ² - 20Kg / cm When sprayed at a spray pressure of ² , the slag 3a and the coating material 10 existing on the inner wall of the converter 1 are solidified due to the coating material 10 to be re-injected and dispersed in the converter 1.

In addition, since the coating material 10 and the like dispersed in the converter 1 do not adhere to the inside of the converter 1 due to the dispersion phenomenon, after the lance 4 is taken out, the converter 1 may be moved in various directions. Lay down in a posture and finally coating while cooling with air, it returns to the step of putting the scrap (2).

Of course, after finishing the tapping of the molten metal, the work waiting until the temperature inside the converter (1) is lowered to a predetermined temperature, and when the cooling to the desired temperature is added to the coating material (10), the coating material (10) Compressive strength of 10Kg / cm²-20Kg / cm²It can be formed into a spherical shape, etc., and has a width of 30mm-60mm It is preferably formed in an almond shape having a size, and filled in the converter 1 in an amount capable of coating the inside of the converter 1 as a whole.

Anyway, the coating material 10 finally dispersed by the injection pressure of nitrogen is coated on the inner wall of the converter (1), after which the lance (4) to the outside of the converter (1) to complete the coating work After the lance 4 is separated from the converter 1, the converter 1 is cooled by air.

In other words, in the present invention, maintaining the temperature when the coating material 10 is injected into the converter 1 at 900 ° C. to 1200 ° C. is a high purity calcium carbonate (CaCO ₃ ) that is not pyrolyzed in the composition of the coating material 10. (1) bar is, by the temperature within the CO ₂ pyrolysis, while CO ₂ is decomposed from the coating (10) as soon coating a smooth inner wall of the converter (1) on the addition of magnesium oxide as a component of the converter (1), the inner wall Due to the carbon and the adhesion of the coating material 10 will be smooth.

In addition, if the injection pressure of the nitrogen injected from the lance 4 is less than 10Kg / cm ^{2 The} coating material 10 is not properly scattered, the overall coating is difficult to achieve evenly, if larger than 20Kg / cm ² If the coating material 10 is scattered This is so severe that degradation of the coating and breakage of the coating material may occur.

As described above, the present invention provides a method for manufacturing a converter inner wall coating material and a method for coating the inner wall of the converter using the same, which is to easily extend the service life of the converter. Improved affinity with, and suppresses the production of low melting point material, such as T Fe, improves the adhesion strength, improves the coating efficiency and extends the service life. When the carbon-containing coating material according to the present invention is added to the carbon, the carbon content of the coating material is 10-25 wt% and MgO because the oxidation of the slag is lowered and the viscosity increases when the carbon is combined with and reacts with the surplus oxygen and iron oxide in the slag. It improves adhesion strength and adhesion efficiency to MgO-C quality converter furnace brick with 70 ~ 90wt% content. That is, carbon-containing coating material is put into slag The carbon in the coating material absorbs and reacts with oxygen (O2) in iron oxides (Fe203, Feo, etc.) contained in slag, and vaporizes into CO or CO2 gas, and iron oxide is converted into Fe and recovered as molten steel. It suppresses the formation of melting point materials (MgO-Fe203, CaO-Fe203), and slag composed of MgO and CaO components is strongly and stably attached to the converter furnace wall. It has excellent erosion resistance against slag and it is combined with only strong materials without low melting point materials such as MgO-Fe203, CaO-Fe203 even at the interface between furnace brick and coating material, so it is physical Even under the impact of the coating, there is no dropout of the coating and protection of the furnace brick can greatly improve the service life of the converter furnace.

As described above, coating the inner wall of the converter using the coating material prepared according to the present invention uses the converter because the inner wall of the converter is coated with a coating material composed of high purity magnesium oxide, high purity calcium carbonate and carbon having good corrosion resistance. The number of charges can be extended to thousands of charges, thereby improving productivity, and in terms of economy, there is an advantage that it is superior to conventional coating materials.

In particular, since the present invention contains a component such as magnesium oxide-carbon (MgO-C), which is a component of the converter inner wall, the affinity with the converter inner wall is increased, thereby increasing the adhesion efficiency.

Furthermore, since the coating material of the present invention contains carbon, it can be put into an electric furnace or the like other than a converter, whereby there is another advantage of realizing the peat action of steel in an electric furnace or the like.

Claims (5)

In the composition of the coating material for coating the inner wall of the converter for fire resistance, 40% to 85% by weight of high purity magnesium oxide containing 95% to 97% by weight of magnesium oxide (MgO); 10 weight percent-35 weight percent of high purity calcium carbonate, containing 95 weight percent-98 weight percent calcium carbonate (CaCO ₃ ); And 5 wt% to 25 wt% of carbon (C). In manufacturing a coating material for coating the inner wall of the fireproof converter, 40% to 85% of high purity magnesium oxide containing 95% to 97% of magnesium oxide (MgO)-85% to 10% of high purity calcium carbonate containing 95% to 98% of calcium carbonate (CaCO ₃ ) Mixing and crushing the mixture composed of 35% by weight, 5% by weight of carbon (C)-25% by weight, Moisture and glue are added to the crushed mixture, which is then kneaded. Molding the kneaded mixture with moisture and glue, A method for producing a fireproof converter inner wall coating material composition comprising naturally drying a molded mixture. The method of claim 2, The crushed mixture is a method of producing a fireproof converter inner wall coating material, characterized in that the shredded to a particle size of 90 mesh-130 mesh. The method of claim 2, A method for producing a fireproof converter inner wall coating, characterized in that 15 to 25% by weight of water and adhesive in the crushed mixture. The method of claim 2, A method of manufacturing a fireproof converter inner wall coating material, characterized in that the mixture of water and adhesive is molded into a mold, but the average particle diameter of the molded mixture is 30 mm-60 mm.