KR100412259B1 - preparations of coating composite of internal wall of converter and coating method using it - Google Patents

Abstract

The coating composition for the inner wall of the converter refractory according to the present invention is 900 ℃ - when the heat treatment by thermal decomposition of CO ₂ in 1200 ℃ 95.33wt% - from magnesite containing MgCO ₃ to obtain a material adjusted to MgO of 96.86wt% CO ₂ High purity MgO obtained by thermal decomposition of 85wt%-90wt%, and 10wt% limestone containing CaCO ₃ to obtain a material adjusted to 92.05wt%-95.51wt% CaO by thermally decomposing CO ₂ by heat treatment at 900 ℃-1200 ℃ It is made by mixing% -15wt%.

In addition, according to the present invention, the method for manufacturing a fireproof converter inner wall coating material is a high purity MgO 85wt%-90wt% left by thermal decomposition of CO ₂ by heat-treating magnesite containing MgCO ₃ at 900 ℃-1200 ℃, limestone containing CaCO ₃ Shredding step of mixing and crushing 10wt%-15wt%; A water mixing step of adding water to the crushed material crushed in the crushing step and then mixing the crushed water; A molding step of molding the mixture mixed in the water mixing step; And it is made of a drying process for transporting the molded product formed in the molding process and drying it.

Furthermore, the coating method of the inner wall of the converter using the fireproof converter inner wall coating material according to the present invention, after finishing the tapping, when the temperature inside the converter is lowered to a constant temperature, limestone containing high purity MgO 85wt%-90wt% and CaCO ₃ 10wt% A charging step of filling the inside of the converter with pellets mixed with 15 wt%; An oxygen lance injection step of injecting an oxygen lance into the converter after the filling process, and disposing a tip end portion of the oxygen lance apart from the upper portion of the pellet; After the oxygen lance is injected into the converter, nitrogen is injected at a high pressure through the oxygen lance, and the coating process is performed by coating the inner wall of the converter by dispersing the pallet in the electric furnace under the pressure of nitrogen.

Therefore, the present invention is to coat the inner wall of the converter using a coating material consisting of a mixture of limestone containing high purity MgO and CaCO ₃ with good corrosion resistance, it is possible to extend the number of times of use of the converter to thousands of charge (charge) to improve productivity In addition to being able to achieve the same effect as that of the conventional coating material in economical efficiency.

Description

Manufacturing method of inner wall coating material for fireproof converter and coating method of inner wall using converter {preparations of coating composite of internal wall of converter and coating method using it}

The present invention is a refractory coating material composition of the inner wall of the converter (Converter) to remove the impurities by oxidative combustion and remove the impurities by blowing oxygen gas or the like in the molten iron of the pig iron contained in the furnace or the surface and The present invention relates to a manufacturing method and a coating method using the same, and more particularly, to a fireproof converter inner wall coating material composition and a method for manufacturing the same, and a converter inner wall coating method using the same, which can easily extend the inner wall life of the converter.

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, the inner wall of the converter is made of magnesium oxide-carbon brick (MgO-C Brick), which has a stronger oxidation erosion than the dolomite brick, thereby extending the number of uses of the converter by more than 1000.

However, since the MgO-C 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.

Therefore, the oxidation prevention technology of MgO-C Brick for the extension of the service life of the converter has been studied and the Vessel tilt slag coating method has been attempted and is widely used. It uses a method of splashing and coating the slag with gas.

It is the viscosity of nitrogen equipment, MgO components and slag, and additionally, additives and operating conditions management, and these nitrogen equipment and MgO usage and conditions can be controlled and adjusted to extend the life of the converter.

The splashing was examined as a nitrogen device and the MgO was examined as light MgO (light spherical), but there was light dolomite, raw dolomite, limestone, etc., but slag splashing with nitrogen was performed to MgO-C Brick. The prolongation of lifespan conditions involve numerous problems.

First, MgO component should be saturated (more than 8wt%) in slag in a short time. For small dolomite, MgO content is 35wt%-40wt%, and MgO purity is low and fluidity is increased at 45wt%-50wt% CaO. This is because the CaO component is high (small sphere: MgO 70wt%-74wt%).

Second, there is an input problem for early control of MaO components (small ton: 1Ton, small tolomite: 2Ton).

Third, when small dolomite is used to control the slag viscosity at a high concentration by increasing the MaO component, increasing the input amount to increase the MgO component increases the CaO content which additionally increases the fluidity.

And if the CaO content is excessive, the phosphorus (P) component reduction is accompanied by a difficult problem.

Fourthly, when using other MgO raw materials other than light bulbs, it must be processed into powder (lump) in powder form.

Fifth, as in the light bulb, the 'sphere' is instantaneously destroyed and dissipated by heat and temperature in the converter, and thus there is a lack of advantages of early diffusion and reaching the appropriate viscosity of slag caking state.

Sixth, when raw dolomite is used, it takes time to decompose the dolomite, and since it is a raw material, the temperature in the furnace is lowered, so that it is not easy to reach the optimum viscosity, and the amount of MgO is low (19-21%) Even if other adverse conditions are taken into account, there is a problem in adjusting the slag viscosity because the CaO content is excessively added.

The present invention has been made to solve the problems of the prior art as described above, the object of the present invention is to adjust the basicity of the slag by adding a certain amount of mild magnesia during the steelmaking of the converter and the MgO of the inner wall of the converter due to the slag The present invention provides a fireproof converter inner wall coating material composition which can easily extend the service life of a converter by minimizing component erosion and protecting the inner wall of the converter, and a method of manufacturing the same and a method of coating the inner wall of the converter using the same. The use of pellets rich in MgO increases the concentration of MgO in the slag and the main component of the built-in brick is MgO, which reduces MgO elution and reduces furnace refractory erosion, thus extending the life of the furnace. A small amount of alumina oxide (Al ₂ O ₃ ) in the alumina cement added together is C The high refractory melt of MgO-CaO-Al ₂ O ₃ is formed in the small pore (pore) area which is generated when aCO ₃ is introduced into the furnace and pyrolyzed into CO ₂ to form a bond due to the melting point temperature of the three-component system. Erosion due to altered layer formation, reaction, and burndown of interior materials is lowered, and affinity with the interior interior materials is increased even at the same basicity and viscosity, so that coating adhesion is firmly formed, even when subjected to impact due to the behavior of molten steel during refining operation. Chemical and physical reactions, which are hot at the same high temperature, protect the furnace brick and extend the life of the furnace.

In order to realize this, the present invention is MgCO ₃ which can obtain a material adjusted to 95.33wt%-96.86wt% MgO when thermally decomposed CO ₂ by heat treatment at 900 ℃-1200 ℃ in the converter wall coating composition for fireproof converter High purity MgO 85wt%-90wt% obtained by thermal decomposition of CO ₂ from magnesite containing, and heat treatment at 900 ℃-1200 ℃ to pyrolyze CO ₂ to obtain a material adjusted to 92.05wt%-95.51wt% CaO Provided is a refractory converter inner wall coating composition comprising 10 wt%-15 wt% of limestone containing ₃ .

In addition, the present invention heat-treated magnesite containing MgCO ₃ at 900 ℃-1200 ℃ by thermal decomposition of CO ₂ crushing to mix and crush the high purity MgO 85wt%-90wt% and CaCO ₃ containing limestone 10wt%-15wt% fair; A water mixing step of adding water to the crushed material crushed in the crushing step and then mixing the crushed water; A molding step of molding the mixture mixed in the water mixing step; And it provides a method for producing a fireproof converter inner wall coating material consisting of a drying step of transporting the molded product formed in the molding process to naturally dry it.

Furthermore, in the present invention, when the temperature inside the converter is lowered to a certain temperature after finishing tapping, the pellets mixed with high purity MgO 85wt%-90wt% and CaCO ₃ containing 10wt%-15wt% of limestone are converted into the inside of the converter. Filling process to fill; An oxygen lance injection step of injecting an oxygen lance into the converter after the filling process, and disposing a tip end portion of the oxygen lance apart from the upper portion of the pellet; And after the oxygen lance is put into the converter, the inner wall of the converter using a fireproof converter inner wall coating material consisting of a coating process of coating the coating on the inner wall of the furnace by dispersing the pallet in the electric furnace under the pressure of nitrogen by spraying nitrogen at high pressure through the oxygen lance. Provides a coating method.

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,

Figure 3 is a block diagram for explaining a coating method of the inner wall of the converter using the coating material composition of the present invention.

<Code Description of Main Parts of Drawing>

1: converter

1a: inner wall

2: pellet

3: oxygen lance

Hereinafter, a preferred embodiment of the converter inner wall coating material composition for fireproof according to the present invention, a method for producing the same, and a method for coating the inner wall of the converter using the same 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 made by mixing high purity MgO 85wt%-90wt% and limestone containing CaCO ₃ 10wt%-15wt%.

The high-purity MgO is a magnesite containing MgCO ₃ 900 ℃ - by heating to 1200 ℃ as a thermal decomposition of CO _2, when the pyrolytic CO ₂ content of 95.33wt% MgO - becomes a 96.86wt%.

In other words, the magnesite containing MgCO ₃ is MgO 40.0wt%-50.0wt%, SiO ₂ 0.25wt%-0.35wt%, Al ₂ O ₃ 0.05wt%-0.1wt%, CaO 1.0wt%-2.0wt% the remaining CO ₂ is coupled to the MgO and CaO in addition to the would joseongdoem yeomsangtae such as MgCO ₃ and CaCO _3, when the thermal decomposition by heating it to _{CO 2 MgO 95.33wt% - 96.86wt%} , SiO 2 0.60wt% -0.67wt High purity MgO consisting of%, Al ₂ O ₃ 0.12wt%-0.19wt% and CaO 2.42wt%-3.81wt% is produced.

Limestone containing CaCO ₃ is to be a composition of the coating material without heat treatment.

Of course, limestone containing CaCO ₃ is thermally decomposed at 900 ℃-1200 ℃ to decompose CO ₂ content of CaO is 92.05wt%-95.51wt%.

In other words, limestone containing CaCO ₃ had a CaO 50.0wt%-55.0wt%, SiO ₂ 1.0wt%-1.5wt%, Al ₂ O ₃ 0.25wt%-0.75wt%, MgO 1.0wt%-2.0wt%, Fe ₂ O ₃ is composed of 0.1wt%-0.5wt% and the remaining CO ₂ is bonded to CaO and MgO to form the same salt state as CaCO ₃ and MgCO _3, and when thermally decomposed CO ₂ by heat treatment, CaO 92.05wt%- 95.51 wt%, SiO ₂ 1.91 wt%-2.51 wt%, Al ₂ O ₃ 0.48 wt%-1.26 wt%, MgO 1.91 wt%-3.34 wt% and Fe ₂ O ₃ 0.19 wt%-0.84 wt% High purity CaO is produced.

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

As shown in FIG. 1, the high purity MgO 85wt%-90wt% remaining by thermally decomposing CO ₂ by heat-treating magnesite containing MgCO ₃ at 900 ° C-1200 ° C, and limestone 10wt%-containing CaCO ₃ The coating material is passed through a crushing fixation (S10) for mixing and crushing 15 wt% as it is, a water mixing step (S20) for mixing moisture, a molding step (S30) for molding into a small size shape, and a drying step (S40) for drying. In this case, the crushed crushed product can be commercialized as it is and the dry coating material can be commercialized.

Here, the shredding step (S10) is a mixture of high purity MgO 85wt%-90wt% and CaCO ₃ limestone 10wt%-15wt% to produce a shredded bar, shredded by a shredder or the like to the particle size of 90 mesh -Shred to 130 mesh.

The water mixing step (S20) is to add water to the crushed crushed in the crushing step (S10) and then to mix it with a mixer or the like, in the water mixing process (S20) to give moldability to the crushed crushed matter Moisture 15wt%-25wt% is added. Of course, after drying, the alumina cement 1wt% ~ to maintain the proper strength, improve the fire resistance, uniform coating and proper elasticity of the coating layer, high melting point bonding of MgO and CaO It is preferable to add moisture containing 2wt%, 6wt% ~ 10wt% of high juice (MgSO ₄ , 7H ₂ O).

The molding step (S30) is to mold the mixture mixed in the water mixing step (S20), the molding of the mixture into a mold, it is preferable that the size of the molding is molded into a pellet of horizontal and vertical 30mm-60mm, The pellet is formed into a spherical shape or an almond shape.

The drying step (S40) is to transfer the molded article formed in the molding process to a drying plant using a belt conveyor, such as to naturally dry it, and to dry the molding to room temperature of 20 ℃-30 ℃ drying temperature and the Preferably, the molding is dried for 24 hours.

The high purity MgO 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.

Of course, when the MgO contained in the high purity MgO is less than or exceeds 95.33wt%-96.86wt%, it is not possible to maintain the viscosity of the slag and maintain the saturated state of the MgO component in the slag and prevent erosion.

Limestone containing CaCO ₃ is converted to high purity CaO as CO ₂ is thermally decomposed during the coating method described below, and the high purity CaO is mixed with the high purity MgO to maintain the fluidity of slag and maintain the saturated state of MgO component in slag. It serves to prevent erosion by infiltration.

Of course, if CaO ₃ contained in the high purity CaO obtained by pyrolysis of CaCO ₃ is less than or exceeds 92.05wt% -95.51wt%, it is infiltrated by maintaining the fluidity of slag and maintaining the saturated state of MgO component in slag. Can not perform the function of preventing erosion.

On the other hand, in the present invention, the limestone containing the high purity MgO and CaCO ₃ , which are large lumps, is crushed into 90 mesh-130 mesh, and when the particle size is larger than the above range, the moldability is poor 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 limestone containing high purity MgO and CaCO ₃ may be packaged and stored as it is after being crushed to a size of 90 mesh to 130 mesh or sold in the packaged state.

In order to give moldability to the mixture of limestone containing high purity MgO and CaCO ₃ , water is added and then kneaded, wherein the addition ratio of the moisture is the total weight of limestone containing high purity MgO and CaCO ₃ . It is 15wt%-25wt% of.

If the moisture is less than 15wt%, the moldability is not good, so that it is difficult to mold easily, and if the moisture is more than 25wt%, the water becomes too high and the handling becomes difficult even if it is molded.

The reason for the size of the molding is 30mm-60mm is for easy handling, and the reason for making the coating material in spherical shape or almond shape is easy handling, less friction between coating materials, and the contact area when coating the converter inner wall. And the molding to the size as described above is to produce a small amount of dust when the input to the inner wall of the converter, and to powder in a quick time after the input into the converter, the coating material prepared in the present invention is a pellet rich in MgO component When MgO is used, the MgO concentration in slag increases, so that MgO elution, which is the main component of the built-in bricks, is extremely low, resulting in less formation, reaction, and dropping of the interior material, and lower erosion, resulting in a lower amount of MgO-CaO in the coating layer attached to the wall. The high melting point compound of -Al ₂ O ₃ is produced, and the structure is firm and elastic, thus maximizing the service life of the converter.

As described above, the coating material for coating the converter inner wall is manufactured, and the coating material manufactured by the above process is packaged and stored or sold.

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

That is, in the coating method of the present invention, as shown in Fig. 2 and 3, the filling step (S100), the pellet (2) filling the pellet 2 into the converter (1) is completed tapping The high pressure nitrogen is injected into the oxygen lance input process S110 for injecting the front end of the oxygen lance 2 into the internal converter 1 and the oxygen lance 2 introduced into the converter 1 to pellet ( 2) is made of a coating step (S120) for coating the inner wall (1a) of the converter (1).

Here, in the filling step (S100), after the tapping is finished, when the temperature inside the converter (1) is lowered to a constant temperature, limestone containing high purity MgO 85wt%-90wt% and CaCO ₃ 10wt%-15wt% mixed and dried The pellet 2 is filled in the converter 1.

At this time, the pellet 2 has a compressive strength of 10Kg / cm²-20Kg / cm²It can be formed into a spherical shape with 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.

In addition, when the temperature inside the converter 1 is lowered to 900 ° C. to 1200 ° C. in the filling process S100, the pellets 2 are introduced. When the temperature in the converter 1 is maintained to 900 ° C. to 1200 ° C. While in the standby state until the temperature reaches the pellet 2 is injected from the top of the converter (1).

In the oxygen lance injection step (S110), the oxygen lance (3) is introduced into the converter (1) after the filling step (S100), but the distal end portion of the oxygen lance (3) is disposed above the pellet (2) Done.

In the coating process (S120) after the oxygen lance (3) is put into the converter (1), the nitrogen is injected at a high pressure through the oxygen lance (3) by the pressure of the nitrogen in the converter (1) inside the pallet (2) To disperse the coating on the inner wall (1a) of the converter (1).

At this time, the injection pressure of the nitrogen is injected through the oxygen lance (3) is 10Kg / cm ² - it is preferable to a 20Kg / cm ^2.

Then, the pellets 2 dispersed at the injection pressure of nitrogen are coated on the inner wall 1a of the converter 1, and then the coating is performed by drawing the oxygen lance 3 to the outside of the converter 1. After the work is completed, the oxygen lance 3 is separated from the converter 1, and the converter 1 is cooled by air.

Here, in the present invention, the temperature at which the pellet 2 is injected into the converter 1 is maintained at 900 ° C. to 1200 ° C., wherein the limestone containing CaCO ₃ which is not pyrolyzed in the composition of the pellet ₂ is converted to a converter. When the CO ₂ is thermally decomposed by the temperature inside (1), the inner wall 1a of the converter 1 is smoothly coated while the CO ₂ is decomposed from the pellets ₂ .

In addition, if the injection pressure of the nitrogen injected in the oxygen lance (3) it is less than 10Kg / cm ² pellets (2) is difficult and becomes a uniformly achieved overall coating can not be properly scattering, is more than 20Kg / cm ² pellets (2 ), Too much scattering of the coating may cause coating degradation and pellet breakage.

As described above, the converter interior wall coating material composition and the manufacturing method thereof according to the present invention and the coating method of the converter inner wall using the same, the slag rich in MgO at the same basicity and viscosity have a strong affinity with the furnace brick having the MgO component of 70 to 80% and adhere the coating. Because the castle is firmly formed, even if it is impacted by the behavior of molten steel during refining operation, the dense structure is formed in the coating layer due to the strong adhesion of the coating and the small amount of Al ₂ O ₃ thermal behavior. As a result, it is easy to extend the service life of the converter.

As described above, coating the inner wall of the converter using the coating material prepared according to the present invention is because the coating of the converter inner wall with a limestone coating material containing high purity MgO and CaCO ₃ with good corrosion resistance, so that the number of times of use of the converter It can be extended to thousands of charge (charge) to improve the productivity and also has the advantage that it is superior to the conventional coating material in economical efficiency. In particular, the present invention by using a pellet rich in MgO component MgO concentration in slag is increased MgO elution, which is the main component of the built-in brick, is extremely low, resulting in less formation of internal materials, altered layer formation, reaction, and dropping, thereby lowering the erosion and maximizing the service life of the converter. Has strong affinity with furnace bricks with 70% to 80% MgO component, resulting in a strong coating adhesion and remaining coating Because the tissue is MgO-CaO-Al ₂ O firmly to the high melting point compounds of ₃ I in combination with themselves and refractory batdeorado the impact of the behavior during the polishing operation the molten steel protect the furnace wall brick with a strong coating attachment life of the refractory It is to extend.

Claims (12)

delete In manufacturing fireproof converter inner wall coating material, 900 ℃ - when the heat treatment by thermal decomposition of CO ₂ in 1200 ℃ 95.33wt% - by thermal decomposition of CO ₂ from magnesite containing MgCO ₃ to obtain a material adjusted to MgO of 96.86wt% pure MgO 85wt% obtained - 90wt% and 900 ℃ - crushing step of crushing mixed with 15wt% heat-treated at 1200 ℃ by thermal decomposition when the 92.05wt% CO ₂ - - containing CaCO ₃ to obtain a material adjusted to 95.51wt% CaO of limestone 10wt%; A water mixing step of adding 15 wt%-25 wt% of water to the crushed material crushed in the crushing step, and then mixing them; A molding process of molding the mixture mixed in the water mixing process into a mold, and molding the pellets having a horizontal and vertical size of the molding from 30 mm to 60 mm; And a method of manufacturing a fireproof converter inner wall coating material, which comprises a drying step of conveying the pellets formed in the molding step and naturally drying them. The method of claim 2, The method of manufacturing a refractory converter inner wall coating material, characterized in that the shredding the particle size of the shredded to 90 mesh-130 mesh in the shredding process. The method of claim 2, 15 to 25 wt% of water is added in the water mixing process, but the alumina cement contains 1 wt% to 2 wt% of the alumina, and 6 wt% to 10 wt% of juice (MgSO ₄ , 7H ₂ O). Method of manufacturing the inner wall coating material. The method of claim 2, The pellets teuneun compressive strength 10Kg / cm ² - process for producing a fire-resistant coating material for electric furnace wall, characterized by formed in a spherical shape of 60mm - 30mm diameter, with a reserved 20Kg / cm ^2. The method of claim 2, The method of manufacturing a refractory converter inner wall coating material, characterized in that the molding is dried at a drying temperature of 20 ℃-30 ℃ in the drying step. The method of claim 6, A method for manufacturing a fireproof converter inner wall coating material, characterized in that the molding is dried for 24 hours. In coating the inner wall of the fireproof converter, 900 ℃ - when the heat treatment by thermal decomposition of CO ₂ in 1200 ℃ 95.33wt% - by thermal decomposition of CO ₂ from magnesite containing MgCO ₃ to obtain a material adjusted to MgO of 96.86wt% pure MgO 85wt% obtained - 90wt% and 900 ℃ - a mixing 15wt% crushed, and crushed - when the heat treatment by thermal decomposition of CO ₂ in 1200 ℃ 92.05wt% - containing CaCO ₃ to obtain a material adjusted to 95.51wt% CaO of limestone 10wt% 15wt%-25wt% of water is added to the crushed material, and then mixed, and the water-mixed mixture is formed into a mold, which is formed into pellets having a size of 30 mm to 60 mm in width and length of the molding, and the formed pellet is transferred. Filling the pellet prepared by natural drying it, the charging step of filling the inside of the converter when the temperature inside the converter is lowered to a certain temperature after the tapping; An oxygen lance injection step of injecting an oxygen lance into the converter after the filling process, and disposing a tip end portion of the oxygen lance apart from the upper portion of the pellet; And after the oxygen lance to the converter after the injection of nitrogen at a high pressure through the oxygen lance to the inner wall of the converter using a coating process for coating the inner wall of the converter by dispersing the pallet inside the converter by the pressure of nitrogen. Coating method. delete delete The method of claim 8, The coating method of the inner wall of the converter using the inner wall coating material for the converter, characterized in that the temperature inside the converter in the filling process is 900 ℃-1200 ℃. The method of claim 8, Coating method of the inner wall of the converter with the converter refractory coating material for the inner wall, characterized in that to 20Kg / cm ² - an injection pressure of nitrogen 10Kg / cm ² in the coating process.