KR19990045879A - A composite of coating material for coating the internal wall of a converter and the method for producing coating material using that - Google Patents

Abstract

The present invention is a coating material composition for extending the inner wall life of the converter (Converter) to remove the impure elements by oxidative combustion and removal by blowing oxygen gas or the like into the molten iron or surface of pig iron contained in the furnace. And it relates to a coating material manufacturing method using the composition, which is MgO: 82-87 wt%, CaO: 11-15 wt%, SiO ₂ : 0.1-1.0 wt%, Al ₂ O ₃ : 0.1-0.3 wt%, Fe ₂ A converter inner wall coating composition composed of O ₃ : 0.3-0.7 wt% and CO ₂ : 0.1-0.5 wt%.

MgO: 82-87 wt%, CaO: 11-15 wt%, SiO ₂ : 0.1-1.0 wt%, Al ₂ O ₃ : 0.1-0.3 wt%, Fe ₂ O ₃ : 0.3-0.7 wt%, CO ₂ : A first step of crushing the dolomite consisting of 0.1-0.5 wt% with a crusher to make 90-130 mesh; A second step of adding and mixing water to give moldability to the dolomite and limestone crushed to be 90 to 130 mesh; A third step of molding the mixture mixed by the second step into an almond form using a mold; A fourth step of transferring the molded article formed by the third step to a drying cabinet using a belt conveyor; A fifth step of naturally drying the molded product transferred by the fourth step at room temperature; The manufacturing method consists of a sixth process of packaging and packaging the molded article dried by the fifth process.

Description

A composite of coating material for coating the internal wall of a converter and the method for producing coating material using that}

The present invention is a coating material composition for extending the inner wall life of the converter (Converter) to remove the impure elements by oxidative combustion and removal by blowing oxygen gas or the like into the molten iron or surface of pig iron contained in the furnace. And to a coating material manufacturing method using the composition.

In general, the furnace 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, and when using the converter 10 constructed of the dolomite brick, hundreds of charges (Charge: of the converter 10) are used. Only the number of times of use) resulted in huge obstacles in productivity as well as economics.

Therefore, in order to solve the above problems, in recent years, by converting the inner wall 20 of the converter 10 into a MgO (magnesium oxide) -C (carbon) brick (brick), which is stronger than the dolomite brick, the converter is used. 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 own non-wetting property.

Therefore, the oxidation-prevention technology of MgO-C Brick for extending the service life of the converter 10 has been studied, and the vessel-type tilt slag coating method has been tried and used. It is applied by splashing the slag with nitrogen gas.

Therefore, it is the viscosity of the nitrogen device, the MgO component and the slag, and additionally the management of additives and operating conditions. These nitrogen systems and MgO usage and conditions 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 light MgO. It is accompanied by a lot of problems.

The reason is first; In a short time, MgO component should be saturated (more than 8%) in slag. For small dolomite, MgO content is 35-40% and CaO component with low MgO purity and fluidity is increased at 45-50% CaO. High (Mgo: 70-74%)

second; It is a dosage issue to control the MgO component early,

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, the phosphorus (P) component is also 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 (lump) in powder form.

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

Sixth; When using dolomite, it takes time to decompose the dolomite, and because it is a raw material, it is difficult to reach the optimum viscosity due to the temperature inside the furnace, 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 adjusts the basicity of the slag by adding a certain amount of limestone and dolomite during the steelmaking of the converter, and minimize the erosion of the MgO component 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 and coating method of the inner wall of the converter.

The present invention having such a purpose is MgO: 82-87 wt%, CaO: 11-15 wt%, SiO ₂ : 0.1-1.0 wt%, Al ₂ O ₃ : 0.1-0.3 wt%, Fe ₂ O ₃ : 0.3 A converter inner wall coating composition composed of 0.7 wt%, CO ₂ : 0.1-0.5 wt%,

MgO: 82-87 wt%, CaO: 11-15 wt%, SiO ₂ : 0.1-1.0 wt%, Al ₂ O ₃ : 0.1-0.3 wt%, Fe ₂ O ₃ : 0.3-0.7 wt%, CO ₂ : A first step of crushing the dolomite consisting of 0.1-0.5 wt% with a crusher to make 90-130 mesh; A second step of adding and mixing water to give moldability to the dolomite and limestone crushed to be 90 to 130 mesh; A third step of molding the mixture mixed by the second step into an almond form using a mold; A fourth step of transferring the molded article formed by the third step to a drying cabinet using a belt conveyor; A fifth step of naturally drying the molded product transferred by the fourth step at room temperature; It characterized in that the manufacture consisting of a sixth step of packaging and commercialized the molded article dried by the fifth step.

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

Figure 2 is a block diagram for explaining a method for coating the converter inner wall with a 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.

MgO (magnesium oxide): 82-87 wt%, CaO (quick lime): 11-15 wt%, SiO ₂ (silicon oxide): 0.1-1.0 wt%, Al ₂ O ₃ (aluminum oxide): 0.1-0.3 wt% , Fe ₂ O ₃ (iron oxide): 0.3-0.7 wt%, CO ₂ : 0.1-0.5 wt% by mixing (hereinafter referred to as dolomite).

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

First, MgO: 82-87 wt%, CaO: 11-15 wt%, SiO ₂ : 0.1-1.0 wt%, Al ₂ O ₃ : 0.1-0.3 wt%, Fe ₂ O ₃ : 0.3-0.7 wt%, CO ₂ : The dolomite consisting of 0.1-0.5wt% is crushed to 90-130 mesh using a crusher.

Once this is done, add moisture to 15-25% to give moldability to the dolomite and mix using a blender to mix it.

When the mixing operation is completed as described above, the mixture is molded into an almond form using a mold, wherein the size of the molded product is molded into an almond form having a length of 30 m / m and a width of 60 m / m.

In this way, the molded article molded in almond form is transferred to a drying plant using a belt conveyor, and the finished molded article is naturally dried at room temperature of 20-30 ° C. for 24 hours to form pellets.

However, the compressive strength of the pellets in the almond form is to maintain 10-20Kg / cm ² .

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

The present invention is first MgO: 82-87 wt%, CaO: 11-15 wt%, SiO ₂ : 0.1-1.0 wt%, Al ₂ O ₃ : 0.1-0.3 wt%, Fe ₂ O ₃ : 0.3-0.7 wt%, CO ₂ : 0.1-0.5 wt%, the reason for using the 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 It is.

However, when the MgO exceeds 82-87 wt% or less, the viscosity of the slag and the saturation of the MgO component in the slag cannot be maintained and erosion cannot be prevented.

In addition, the CaO is to maintain the fluidity of the slag, to maintain the saturated state of the MgO component in the slag to prevent erosion by infiltration.

However, when the CaO exceeds 11-15 wt% or less, the above-described role, that is, prevents erosion by the infiltration due to maintaining the fluidity of the slag and maintaining the saturated state of the MgO component in the slag.

In addition, the present invention breaks the dolomite with a crusher so as to form a 90-130 mesh in a large lump form, because if it exceeds the 130 mesh, the moldability is not good, and also easily broken, if the mesh is less than 90 This is because it is scattered and difficult to handle.

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

The dolomite and limestone crushed to 90-130 mesh are added with water to give moldability, and then mixed with a mixer, wherein the addition rate of the water is dolomite + limestone 75-85: moisture 15-25%. It is preferable to set it as.

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

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 to facilitate handling, less friction between the coating materials, and to increase the contact area when coating the converter 10 and the inner wall 20.

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 transported is naturally dried for 24 hours at room temperature.

The inner wall 20 of the converter 10 is coated with the coating material prepared as described above. The coating method is as follows.

According to the present invention, when the tapping work of the converter 10 is completed, the working state is maintained until the temperature in the converter 10 is maintained at 900-1200 ° C. When the temperature of the converter 10 is 900-1200 ° C, Pellets are injected at the top of the converter 10.

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 nitrogen of the high pressure, 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 made, if it 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 may be removed from the converter 10.

The present invention as described above can be used to coat the inner wall of the converter using a good corrosion resistance dolomite can extend the number of times of use of the converter to improve the productivity, as well as economical than conventional coating materials This is a great effect.

Claims (2)

MgO (magnesium oxide): 82-87 wt%, CaO (quick lime): 11-15 wt%, SiO ₂ (silicon oxide): 0.1-1.0 wt to form an inner wall coating of the converter to improve the lifetime of the converter %, Al ₂ O ₃ (aluminum oxide): 0.1-0.3 wt%, Fe ₂ O ₃ (iron oxide): 0.3-0.7 wt%, CO ₂ : 0.1-0.5 wt%, the converter inner wall coating composition. In preparing the coating material of the inner wall of the converter to improve the lifetime of the converter, MgO: 82-87 wt%, CaO: 11-15 wt%, SiO ₂ : 0.1-1.0 wt%, Al ₂ O ₃ : 0.1-0.3 wt A first step of crushing the dolomite consisting of%, Fe ₂ O ₃ : 0.3-0.7 wt%, and CO ₂ : 0.1-0.5 wt% to a 90-130 mesh; A second step of adding and mixing water to give moldability to the dolomite and limestone crushed to be 90 to 130 mesh; A third step of molding the mixture mixed by the second step into an almond form using a mold; A fourth step of transferring the molded article formed by the third step to a drying cabinet using a belt conveyor; A fifth step of naturally drying the molded product transferred by the fourth step at room temperature; 6. A method for manufacturing a converter inner wall coating material, comprising a sixth step of packaging and packaging a molded product dried by the fifth step.