KR19990083760A - A composite of coating material and the manufacturing method there of and the coating material and the method for coating the internal wall of a converter using the coating material - Google Patents

Abstract

The present invention is a coating material composition for prolonging the inner wall life of the converter (Converter) by oxidizing and burning the harmful components contained in the molten metal by blowing oxygen gas, etc. into the molten iron of pig iron in the furnace. And a method for preparing a coating material, an article prepared by the method, and a method for coating an inner wall of the converter using the article, including: MgO: 40-50 wt%, SiO ₂ : 0.25-0.35 wt%, Al ₂ O ₃ : 0.05 MgCO ₃ composed of 0.1 wt%, CaO: 1-2 wt%, CO ₂ : 45-55 wt% was thermally decomposed to 900-1200 ° C. to decompose CO ₂ , and the remaining MgO: 95.33-96.86 wt%, SiO ₂ : Pure MgO consisting of 0.60-0.67 wt%, Al ₂ O ₃ : 0.12-0.19 wt%, CaO: 2.42-3.81 wt%: 70-84 wt%; CaO: 50-55 wt%, SiO ₂ : 1.0-1.5 wt%, Al ₂ O ₃ : 0.25-0.75 wt%, MgO: 1.0-2.0 wt%, Fe ₂ O ₃ : 0.1-0.5 wt%, CO ₂ : A converter inner wall coating composition composed of 40 to 45 wt% of CaCO ₃ : 16 to 30 wt%;

Thermally decomposing CO ₂ by heat-treating MgCO ₃ at 900-1200 ° C. and crushing the remaining pure MgO: 70-84 wt% and CaCO ₃ : 16-30 wt% with a shredder to a 90-130 mesh; A second step of adding 15-25% water to give moldability to the fine particles crushed by the first step, and mixing with a blender to mix them; A third step of molding the mixture mixed by the second step using a mold and transferring the mixture to a drying shop; A method for manufacturing a converter inner wall coating material manufactured by a fourth process of naturally drying the molded product transferred by the third process at 20-30 ° C and then packaging and commercializing the molded article,

Pure MgO 70-84 wt%: CaCO ₃ 16-30 wt%, the compressive strength is 10-20Kg / ㎝ ² , the shape of the almond-shaped pellets,

When the temperature inside the converter 10 is lowered to a predetermined temperature after the tapping, the almond-shaped pellets having a mixing ratio of pure MgO: 70-84 wt% and CaCO ₃ : 16-30 wt% are converted to a converter (10). A) first step of filling the inside into an appropriate amount; When the first process is completed, the nitrogen is injected into the oxygen lance 30 at 10-20kg / cm ² pressure so that the pallet is fused to the inner wall 20 of the converter 10 while being dispersed in the converter 10 by the pressure of nitrogen. A second step of performing; After the second process is completed, the method consists of a third process of drawing the oxygen lance 30 introduced into the converter 10 to the outside of the converter 10 and air-cooling the coating.

Description

A composite of coating material and the manufacturing method there of and the coating material and the method for coating the internal wall of a converter using the coating material}

The present invention oxidizes and burns harmful components contained in the molten metal by blowing oxygen gas into the molten iron of the iron in the furnace, and also extends the inner wall life of the converter (refiner) using the heat. A method for producing a composition and a coating material, and an article manufactured by the method, and a method for coating the inner wall of the converter using the article, which are outside the technical scope of the patent application No. 99-3687, the applicant of the present application, are useful industrially. It is to be used.

In general, the converter 10 operation blows oxygen (O ₂ ) into the molten steel to remove carbon (C) and other harmful components (P, S) in the molten steel, as well as to control the steel components to clean the steel. It is a production operation.

The inner wall 20 of the conventional converter 10 is constructed of Dolomite Brick, which is vulnerable to oxidation erosion. Thus, when the converter 10 constructed of the dolomite brick is used, hundreds of charges (Charge: of the converter 10) are used. Only a number of times of use) resulted in enormous disruptions in productivity as well as economics.

Accordingly, in order to solve the above problems, in recent years, by using the MgO (magnesium oxide) -C (carbon) Brick (brick), which has a stronger oxidation erosion than the dolomite brick, the inner wall 20 of the converter 10 is used to convert the converter. The number of uses of (10) was extended to over 1000 charges.

However, since the MgO-C Brick also blows oxygen, there is a limit to extending the service life of the converter 10 to several thousand depending on its non-wetting property, which is its physical property.

Therefore, the oxidation-prevention technology of MgO-C Brick for extending the service life of the converter 10 has been researched, and has been widely used because the Vessel tilt slag coating method has been tried. The device is splashed and coated with slag of nitrogen gas.

Thus, it is the viscosity of the nitrogen system, the MgO component and the slag, as well as additives and operating condition management. These nitrogen systems and the method and conditions of MgO use must be well coordinated and managed to extend the life of the converter 10.

The splashing is examined as a nitrogen device, and the MgO is examined as a light MgO (hard sphere). There are light dolomite, fresh dolomite, and limestone, but slag splashing with nitrogen is used to extend the life of the MgO-C Brick. Without many problems.

The reason is first; In a short time, the MgO component should be saturated (more than 8%) in the slag. For small dolomites, the MgO content is 35-40%, and the CaO component is low in MgO purity and increases in fluidity at 45-50% CaO. It is high (small diameter: MgO: 70-74%).

second; Is a dose issue for early control of the MgO component,

Example: Gyeongso-gu: 1Ton Gyeongso Dolomite: 2Ton

third; This is because when the input amount is increased to increase the MgO component when using light dolomite when controlling the slag viscosity at high concentration by increasing the MgO component, the CaO content which additionally increases the fluidity increases.

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

fourth; This is because when using other MgO raw materials other than light bulbs, they must be processed into powder in the form of powder.

fifth; Like the light bulb, the "sphere" is instantaneously destroyed and dissipated by heat and temperature in the converter 10, and thus there is a shortage of advantages of early diffusion and reaching the appropriate viscosity of the slag caking state.

Sixth; When dolomite is used, it takes time to decompose the dolomite, and because it is a raw material, it is difficult to reach the optimum viscosity because the temperature in the furnace is lowered, and the amount of MgO is low (19-21%). In addition, even in view of other adverse conditions, the CaO content is excessively added, so there are many problems in adjusting the slag viscosity.

The present invention is to adjust the basicity of the slag by adding a certain amount of light magnesia during steelmaking and to minimize the MgO component erosion of the inner wall of the converter due to the slag to protect the inner wall of the converter to extend the service life of the converter It is an object of the present invention to provide a coating material composition of the inner wall of the converter, a method of manufacturing the coating material, an article manufactured by the method and a method of coating the inner wall of the converter using the article.

The present invention having such a purpose is MgO: 40-50 wt%, SiO ₂ : 0.25-0.35 wt%, Al ₂ O ₃ : 0.05-0.1 wt%, CaO: 1-2 wt%, CO ₂ : 45-55 MgCO ₃ consisting of wt% was heat-treated at 900-1200 ° C to decompose CO ₂ , and the remaining MgO: 95.33-96.86 wt%, SiO ₂ : 0.60-0.67 wt%, Al ₂ O ₃ : 0.12-0.19 wt%, CaO: Pure MgO consisting of 2.42-3.81 wt%: 70-84 wt%; CaO: 50-55 wt%, SiO ₂ : 1.0-1.5 wt%, Al ₂ O ₃ : 0.25-0.75 wt%, MgO: 1.0-2.0 wt%, Fe ₂ O ₃ : 0.1-0.5 wt%, CO ₂ : A converter inner wall coating composition composed of CaCO ₃ : 16-30 wt% comprising 40-45 wt%.

Thermally decomposing CO ₂ by heat-treating MgCO ₃ at 900-1200 ° C. to crush the remaining pure MgO: 70-84 wt% and CaCO ₃ : 16-30 wt% with a shredder to a 90-130 mesh; A second step of adding 15-25% of moisture to give moldability to the fine particles crushed by the first step, and mixing with a blender to mix them; A third step of molding the mixture mixed by the second step using a mold and transferring the mixture to a drying shop; A method for manufacturing a converter inner wall coating material manufactured by a fourth process of naturally drying the molded product transferred by the third process at 20-30 ° C. and then packaging and commercializing the molded article,

Pure MgO 70-84 wt%: CaCO ₃ 16-30 wt%, the compressive strength is 10-20Kg / ㎝ ² , the shape of the pellets made of almond shape,

When the temperature inside the converter 10 is lowered to a predetermined temperature after finishing tapping, a pellet having a mixing ratio of pure MgO: 70-84 wt% and CaCO ₃ : 16-30 wt% is titrated in the converter 10. A first step of filling by an amount; When the first process is finished, the oxygen lance 30 is sprayed with nitrogen at a pressure of 10-20 kg / cm ² so that the pallet is dispersed in the converter 10 by nitrogen injection pressure and coated on the inner wall 20 of the converter 10. A second step; After the second process is completed, the oxygen lance 30 introduced into the converter 10 is drawn out to the outside of the converter 10, and is then made of a third process of air cooling.

1 is a process chart for producing a coating material of the present invention

Figure 2 is a process chart for coating the converter inner wall with the coating material of the present invention

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

[Code Description of Main Part of Drawing]

10: converter

20: inner wall

30: oxygen lance

The present invention first describes the composition of the coating material of the inner wall of the converter for extending the life of the converter.

MgCO ₃ consisting of MgO: 40-50 wt%, SiO ₂ : 0.25-0.35 wt%, Al ₂ O ₃ : 0.05-0.1 wt%, CaO: 1-2 wt%, CO ₂ : 45-55 wt% Pyrolysis of CO ₂ by heat treatment at 1200 ℃ MgO: 95.33-96.86 wt%, SiO ₂ : 0.60-0.67 wt%, Al ₂ O ₃ : 0.12-0.19 wt%, CaO: 2.42-3.81 wt% MgO: 70-84 wt%; CaO: 50-55 wt%, SiO ₂ : 1.0-1.5 wt%, Al ₂ O ₃ : 0.25-0.75 wt%, MgO: 1.0-2.0 wt%, Fe ₂ O ₃ : 0.1-0.5 wt%, CO ₂ : CaCO ₃ : 16-30 wt% consisting of 40-45 wt% is mixed.

The configuration of the method for producing a coating material using the composition thus constituted is as follows.

First, pure MgO: 70-84 wt% and CaCO ₃ : 16-30 wt% are crushed to 90-130 mesh with a crusher, and water is added to 15-25% to impart moldability to the crushed microparticles. Add and mix into a blender.

When the mixing operation is completed as described above, the mixture is molded by using a mold, wherein the size of the molded product is 30m / m in length, 60m / m in the shape of almonds, and using a belt conveyor to the drying cabinet Transfer and dry naturally at 20-30 ℃ for 24 hours.

In addition, the pellet structure of this invention is as follows.

Pure MgO 70-84wt%: CaCO ₃ 16-30 wt% ratio, the compressive strength is 10-20Kg / ㎝ ² , the shape is made of pellets to make a pellet (pellet).

In addition, the converter inner wall coating method of the present invention is as follows.

After finishing tapping, when the temperature inside the converter 10 becomes 900-1200 ° C, the pellets are mixed with pure MgO: 70-84 wt% and CaCO ₃ : 16-30 wt%. Fill in the right amount.

When the filling operation of the pellet is completed as described above, the oxygen lance 30 is introduced such that the end portion of the oxygen lance 30 is located at the upper portion of the pellet, and then nitrogen is introduced through the oxygen lance 30. Spraying at 20 Kg / cm ² pressure ensures that the pallet is evenly dispersed in converter 10 by the pressure of nitrogen.

In this way, since the dispersed pellets maintain a predetermined viscosity, the coating is performed while being fused to the inner wall 20 of the converter 10, after which the oxygen lance 30 is drawn out of the converter 10. Air-cooled (natural cooling).

Referring to the operation of the present invention configured as described above is as follows.

In order to obtain pure MgO, the present invention first obtains MgO: 40-50 wt%, SiO ₂ : 0.25-0.35 wt%, and Al ₂ O ₃ : 0.05-0.1 wt%, CaO: 1-2 wt%, and CO ₂ : obtained by heat-treating MgCO ₃ consisting of 45-55 wt%, the reason for using pure MgO is to maintain the high viscosity of the slag, to maintain the saturated state of the MgO component in the slag to prevent erosion by infiltration will be.

However, when MgO exceeds 95.33-96.86 wt% or less in the pure MgO, the viscosity of the slag is not maintained, and the saturation of the MgO component in the slag is not maintained, and erosion cannot be prevented.

In addition, the present invention is CaCO ₃ mixed with the pure MgO is CaO: 50-55 wt% and SiO ₂ : 1.0-1.5 wt% and Al ₂ O ₃ : 0.25-0.75wt% and MgO: 1.0-2.0 wt%, And Fe ₂ O ₃ : 0.1-0.5 wt%, CO ₂ : 40-45 wt%, CaO of the composition is prevented by erosion by infiltration due to maintaining the fluidity of the slag and maintaining the saturated state of MgO component in the slag And so on.

However, if CaO ₃ exceeds or falls below 50-55 wt%, CaCO ₃ does not perform the above functions, that is, to prevent erosion by infiltration due to maintaining fluidity of slag and maintaining saturated state of MgO component in slag. .

In addition, the present invention crushes the pure MgO: 70-84 wt% and CaCO ₃ : 16-30 wt% with a crusher to form 90-130 mesh in the form of bulky lumps, for more than 130 mesh This is because the moldability is not good, the adhesion is poor, easily broken, and when it is 90 mesh or less, it is scattered and difficult to handle.

However, after crushing the pure MgO and CaCO ₃ into 90-130 meshes of a size suitable for use, the package may be stored or sold in the packaged state.

The pure MgO and CaCO ₃ crushed to be 90-130 mesh and CaCO ₃ is mixed with a mixer after adding water to give moldability, wherein the addition rate of the water is pure MgO + CaCO ₃ 75-85%: moisture It is preferable to set it as 15-25%.

The reason is that when the moisture is 15% or less, the moldability is not good, and molding cannot be performed. When the moisture is more than 25%, the molding becomes difficult due to the excessively high degree of molding.

In addition, after the addition of water, the mixture is then molded using a molding machine (mould), and the size of the molded product is 30 m / m in length and 60 m / m in width to form almonds. Make.

The reason for the size of the molded article to be 30 m / m in length and 60 m / m in width is to facilitate handling.

In addition, the reason for making the coating material in the form of almonds is for easy handling, less friction between the coating materials, and to increase the contact area when coating the inner wall 20 of the converter 10.

On the other hand, the product is molded using the molding machine is transferred to a drying plant using a belt conveyor, the molded article thus transferred is allowed to dry naturally, that is, air-cooled for 24 hours at room temperature.

The operation as described above relates to a method of manufacturing a coating material for coating the inner wall 20 of the converter 10. When the production of the coating material is completed by the above process, the packaging is stored or sold.

In addition, the present invention is to coat the inner wall 20 of the converter 10 with the coating material prepared as described above, the coating method is as follows.

In the present invention, when the tapping operation of the converter 10 is completed, the working state is maintained until the temperature in the converter 10 is maintained at 900-1200 ° C, and when the temperature reaches the temperature, the pellet is injected from the top of the converter 10. do.

When the pellet injection operation into the converter 10 is completed as described above, the oxygen lance 30 is injected into the converter 10, and then high pressure nitrogen is blown into the oxygen lance 30. When the pellet is scattered in the converter 10 by the high-pressure nitrogen, the pellet is attached to the inner wall 20 of the converter 10 to form a coating.

However, when the oxygen lance 30 is injected into the converter 10, the end of the oxygen lance 30 does not come into contact with the upper portion of the pellet injected into the converter 10.

In addition, the temperature at the time of injecting the pellets into the converter 10 should be maintained at 900-1200 ° C., which is a temperature at which the pellets do not thermally decompose, and also injects nitrogen into the oxygen lance 30 to pellets. The spraying pressure at the time of scattering is suitably 10-20Kg / cm <^2> .

However, when the injection pressure is 10Kg / ㎝ ² or less, the pellet is not scattered properly, the coating is not evenly achieved, and if the spray pressure exceeds 20Kg / ㎝ ² , the scattering of the pellet is too severe, there is a problem in the coating, of course, There is a problem that the net is broken.

When the coating is made in the converter 10 as described above, the oxygen lance 30 is removed from the converter 10.

As described above, the present invention manufactures a coating material made of pure MgO and pure CaO having good corrosion resistance on the inner wall of the converter, and by using the coating on the inner wall of the converter, the number of times of use of the converter can be extended to several thousand charges to improve productivity. Of course, there is an effect that is much better than the conventional coating material also in economics.

Claims (4)

In forming the inner wall coating of the converter to improve the lifetime of the converter, MgO: 40-50 wt%, SiO ₂ : 0.25-0.35 wt%, Al ₂ O ₃ : 0.05-0.1 wt%, CaO: 1-2 wt %, CO ₂ : 45-55 wt% of MgCO ₃ by heat treatment at 900-1200 ℃ thermal decomposition of CO ₂ MgO: 95.33-96.86 wt%, SiO ₂ : 0.60-0.67 wt%, Al ₂ O ₃ : Pure MgO consisting of 0.12-0.19 wt%, CaO: 2.42-3.81 wt%: 70-84 wt%; CaO: 50-55 wt%, SiO ₂ : 1.0-1.5 wt%, Al ₂ O ₃ : 0.25-0.75 wt%, MgO: 1.0-2.0 wt%, Fe ₂ O ₃ : 0.1-0.5 wt%, CO ₂ : A converter wall coating composition, characterized in that the composition consisting of 40 to 45 wt% of CaCO ₃ : 16-30 wt% by mixing. In manufacturing the coating material of the inner wall of the converter to improve the life of the converter, the thermal decomposition of MgCO ₃ by heat treatment at 900-1200 ℃ CO ₂ and the remaining pure MgO: 70-84 wt%, CaCO ₃ : 16-30wt% A first step of shredding with a shredder to make 90-130 mesh; A second step of adding 15-25% water to give moldability to the fine particles crushed by the first step, and mixing with a blender to mix them; A third step of molding the mixture mixed by the second step using a mold and transferring the mixture to a drying shop; A method for manufacturing a converter inner wall coating material, comprising a fourth step of manufacturing the molded product transferred by the third step at 20-30 ° C and then drying and packaging the product. In forming the coating material of the inner wall of the converter to improve the lifetime of the converter, the ratio of pure MgO 70-84 wt%: CaCO ₃ 16-30 wt%, the compressive strength is 10-20Kg / cm ² , Pellets characterized by the shape of the almond. In coating the inner wall of the converter to improve the life of the converter, when the temperature inside the converter 10 is lowered to a predetermined temperature after finishing tapping, pure MgO: 70-84 wt% and CaCO ₃ : 16-30 wt% A first step of filling the pellets in the form of almonds having a mixing ratio of an appropriate amount into the converter 10; When the first process is completed, the nitrogen is injected into the oxygen lance 30 at 10-20kg / cm ² pressure so that the pallet is fused to the inner wall 20 of the converter 10 while being dispersed in the converter 10 by the pressure of nitrogen. A second step of performing; After the second process is completed, the coating of the inner wall of the converter, characterized in that the coating consisting of a third step of drawing the oxygen lance (30) introduced into the converter (10) outside the converter (10) and then air-cooled.