KR100851952B1 - Method for early-discharging low-reductive material produced in repairing blast furnace wall - Google Patents

Abstract

The present invention relates to a method for premature release of hard-reducing materials in the repair of furnace furnace walls. As a gas barrier agent, superfine silica (SiO ₂ ) having a particle size of 2 mm or less and a melting point of 600 to 700 ° C. or slag having a basicity of 1.12 or less and a basic slag of It is characterized by the use of a mixture with slag, which protects the equipment from deterioration during spray maintenance and makes it easy to check the condition inside the furnace. By minimizing heat dissipation, it is possible to shorten the time to secure the heat when the normal operation is increased after the spray repair is completed.

Reducing Reduction, Furnace Wall, Repair, Choja Silica, Tripod Suit

Description

Method for early-discharging low-reductive material produced in repairing blast furnace wall}

1 is a schematic diagram showing the internal condition of the blast furnace during normal operation.

2 is a cross-sectional view of the furnace situation and the blocker distribution in the prior art during the furnace furnace wall repair.

Figure 3 illustrates a blocker distribution according to the present invention.

Figure 4 illustrates the shape of the charge surface sealant distribution of the prior art and the present invention.

Figure 5 shows the normal operation degree before and after the re-blowing operation according to the present invention.

* Description of the symbols for the main parts of the drawings *

1: furnace 2: spray equipment

3: reduction level 4: furnace contents

5: windball 6: exit

7: Feed Gun 8: Hopper

9: spray nozzle 10: charge

10d: Charge Level 11: Gas Blocker

12: Slag 13: Mixed Layer (Coke)

14 core coke 15 gas flow in furnace

16: super silica sand 101: hose

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The present invention relates to a method for premature release of hard-reducing materials in the repair of furnace furnace walls, and more particularly, to include ultra-fine silica (SiO ₂ ) containing a small amount of hard-reducing material as a gas barrier agent and a large amount of components to improve the fluidity of the melt. Alternatively, the use of a mixture of vitreous silica and slag protects the equipment from deterioration during the spray repair period, making it easier to check the condition inside the furnace, and the heat dissipation of the contents of the furnace inside the furnace during the idle period. This method relates to a method for premature release of hard-reducing materials during the repair of furnace furnace walls, which can shorten the time to secure the furnace when the normal operation degree rises after the completion of spray repair.

In general, the main body of the furnace is made of iron shell on the outside, the inside is made of a refractory to withstand high temperatures, and between the edges and inserting a cooling plate (not shown) to protect the iron shell at high temperatures. It is supposed to be done. First, through the charging inlet of the upper furnace charging equipment as shown in Figure 1, the fuel coke and the iron ore as raw materials are alternately charged in a layered manner, the hot hot air warmed from the hot stove (Hot Stove) to the lower part of the furnace (1) Blow into coke 5 to burn coke to produce heat and reducing gas. At this time, the generated heat and reducing gas reduce and melt iron ore in the furnace to generate pig iron and slag, and the melt is discharged through the outlet of the lower part of the furnace.

The longer the life of the furnace, the more the damage and abrasion of the refractory, the more protruding, the greater the amount of breakage, the red shell and cracks are an unstable operation.

Therefore, in order to solve such a problem, periodic furnace wall repair is required. In order to repair such a furnace wall spray, spray equipment 2 after lowering the charge 10 in the furnace to the furnace wall repair site as shown in FIG. By spraying the high pressure air and the spray agent stored in the reservoir (8) to repair the damaged portion of the inner wall of the furnace. At this time, the sprayer repairs damaged smoke while moving and rotating up and down in the furnace.

However, as shown in FIG. 2, when the spray equipment 2 is used in the furnace for a long time during the rotation maintenance period, the heat-sensitive hose 101 and the nozzle 9 are degraded and replaced by the gas and heat rising from the furnace. The work must be done, and extra time is required for this, which causes the maintenance time to be extended. The replacement work due to the damage of the hose depends on the repair volume, but it is performed 2 ~ 5 times during the repair of the furnace wall. In addition, when the gas flow is blocked in the furnace, it is difficult to observe the furnace by the dust coming out of the gas, making it difficult for spray repair workers to find locally worn parts of the furnace wall, and it is difficult to check the spray repair status. In addition, there is a large amount of heat dissipation of the charges in the furnace, which requires a lot of time to secure the furnace when the operation degree rises after completion of the spray repair, resulting in an increase in the basicity, and a rise in the basicity during the re-blowing, which results in the discharge of the melt. Since the delay affects the normal operation, surface gas barriers have been applied to prevent this.

Conventionally, as the surface gas barrier agent, grain ore, sintered ore, silica, limestone, handmade slag, insulating castable, mill scale and slag were used. Among them, blockers except mill scale and slag were not used well because of their low frequency of use and poor sealing effect.

Millscale is an iron oxide (FeO), a representative hard-reducing substance that acts as an important factor of melt discharge in the furnace process as described in the table of blockers in Table 1 below, and alumina (Al ₂ O) which deteriorates the fluidity of slag and molten iron. ₃ ) Because it contains a large amount of components, it is difficult to reduce and dissolve in the smelting furnace and deteriorate the flowability of molten iron and slag, making it difficult to discharge the melt after re-blowing. There is a problem that causes.

FeO CaO SiO ₂ Al ₂ O ₃ MgO Fe ₂ O ₃ Other impurities Spray material 0 3.1 34.1 58.3 0 0.14 Remaining amount Mill scale 59.9 0.1 0.2 0.1 0.1 35.2 Remaining amount Slag 0.4 42 34.5 13.3 5.8 0.44 Remaining amount

In addition, the mill scale has a high basicity, which is an important factor influencing the flow of the furnace slag, and in order to improve the fluidity of the slag, it is inevitable that a large amount of silica (SLS.K) or limestone (LMS.K) needs to be charged during the repair of the furnace wall. There is a problem of increasing the cost of the molten iron due to unnecessary loading of ore.

As described above, not only the problem of using ore containing a large amount of hard-reducing substance as a blocker component, but also the hard-reducing substance contained in the refractory sprayed during spray repair is aggregated on the surface blocking agent due to the rebound loss. Since it does not reduce melting after re-blowing, it reduces the flowability of slag and induces air permeation resistance to charges. Therefore, the problem of minimizing the problems mentioned above by changing the material of the sealing material is changed. This has been required.

Accordingly, the present invention has been provided to solve the above problems more efficiently, the object of which is a gas barrier agent containing a small amount of the redox material and a large amount of components for improving the flowability of the melt (SiO ₂ ) Alternatively, by using a mixture of vitreous silica and slag, it is possible to achieve an early rise in operation during re-transmission, and by applying an alternative blocker having a component that can double the blocking effect of the gas barrier agent according to the prior art, It prevents deterioration of spray equipment due to dissipation, makes it easy to check the inside of the furnace, and minimizes heat dissipation of the contents inside the furnace during the period of idle air. To provide a method for premature release of non-reducing substances in the repair of furnace furnace walls. Will.

In order to achieve the above object, the method for early discharging of hard-reducing materials during repair of a furnace furnace according to the present invention is a method for premature discharge of hard-reducing materials for repairing a furnace furnace wall in general. It is characterized in that the use of a mixture of ultra-fine silica (SiO ₂ ) or the slag having a basicity of 1.12 or less at 700 ℃.

In addition, the method for discharging the hard-reducing substance of the present invention is charged with the fine-grained silica (SiO ₂ ) at each loading position of the topless loading chute at 1 to 4 revolutions, and then slag (slag) at each loading position of the topless loading chute. After charging at a rotational speed of 1 to 4, the mixed layer containing slag and superfine silica sand at a weight ratio of 3: 7 to 2: 8 was charged to each charging position of the topless loading chute at 1 to 4 rotational speeds, It is characterized in that the gas barrier agent is charged by loading the ultra-fine silica sand in each of the charging positions of the top charging chute at a rotation speed of 3 to 5. More preferably, the ultrafine silica (SiO ₂ ) is rotated 3 3 3 3 2 2 2 2 2 1 1 at the charging position of the 1 2 3 4 5 6 7 8 9 10 11 point of the top loading chute. After charging with slag, the slag was charged with 3 3 2 2 2 2 2 2 2 2 2 2 at the charging position of 1 2 3 4 5 6 7 8 9 10 11 point of the top loading chute. Afterwards, the mixed layer containing slag and superfine silica sand at a weight ratio of 3: 7 is placed at the charging position of 1 2 3 4 5 6 7 8 9 10 11 point in the top loading chute 3 3 3 2 2 2 2 2 2 2 1 After charging with the number of revolutions, the gas barrier agent is charged by loading the ultra-fine silica sand at 4 4 4 revolutions at the charging position of 9 10 11 point of the topless loading chute.

Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

The ultrafine silica sand (SiO ₂ ) and slag used as the gas barrier agent in the present invention are stored in each raw material storage tank until the start of the decompression operation for repairing the furnace wall. Thereafter, a predetermined amount of the gas barrier agent is temporarily stored in the raw material storage tank and then moved to the charging hopper at the upper part of the furnace using a belt conveyor, and the moved gas barrier agent is stored at the wall using the charging chute at the lower part of the charging hopper. It is charged while rotating to the center at a predetermined number of times at each position.

In the present invention, the ultrafine silica sand used as a gas barrier agent contains a large amount of a component that improves fluidity, and when the melting point is reached, the gas barrier effect is good in the internal atmosphere of the furnace, and the cohesion force is strong and the sealing effect is good, as well as pressurization for re-blowing. When the temperature of the charge surface rises, it is easily dissolved and decomposed compared to other ores, and is easily discharged into the furnace. Since the ultrafine silica sand has a problem that perfect gas blocking is difficult when the particle size is larger than 2 mm, it is preferable to use the ultrafine silica sand having a particle size of 2 mm or less. Moreover, in order to make the said effect further larger, it is preferable to make melting | fusing point into the range of 600-700 degreeC, More preferably, you may be 600 degreeC.

That is, as shown in Table 2, the ultra-fine silica sand contains a small amount of alumina (Al ₂ O ₃ ) component that deteriorates the fluidity of FeO and slag and pig iron (representative hard-reducing material) fast time after re-blowing Since it has the advantage of increasing the normal operation inside, it is possible to facilitate the work by blocking the perfect gas when repairing the wall, and also to ensure quick breathability and reflow of the melt (slag and molten iron) after re-blowing work. It shows the characteristics that can secure the liquidity early.

ingredient SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ MgO CaO Li ₂ O Other impurities Ingredient Content (wt%) 73.12 7.77 0.032 0.08 10.65 3.35 Remaining amount

In the present invention, slag (Slag) can be used mixed with the ultra-fine silica sand is more preferably melted than other charges used in the furnace to limit the basicity (CaO / SiO ₂ ) is also less than 1.12 in order to improve the fluidity when discharged. More preferably, those of 1.10 to 1.12 are used.

In the prepared gas barrier agent, since the gas flow in the furnace is distributed in the order of the center, the wall, and the middle in order to operate the furnace, the gas flows most in the center, so that the shape of the gas barrier agent is increased in the center as shown in part A of FIG. To increase the gas barrier effect.

The charging chute is divided by angles from 1 to 11 so that it can be tilted up and down while charging inside the furnace, and the smaller the number is, the larger the angle is, so as to rotate as desired at each of the predetermined tilt angles. It is then possible to spray a gas barrier on the wall.

In the present invention, preferably, the superfine silica sand (SiO ₂ ) is charged at the rotational speed of 1 to 4 at each charging position of the topless loading chute by the tilting angle, the rotational speed, and the flow control device of the chute, and then the slag. Is charged into each charging position of the top loading chute at 1 to 4 revolutions, and then a mixed layer containing slag and superfine silica at a weight ratio of 3: 7 to 2: 8 is placed at each loading position of the top loading chute. The gas barrier agent is charged by charging at a rotational speed of 3 to 5 at each charging position of the topless charging chute after charging at a rotational speed of. Most preferably, the ultrafine silica sand (SiO ₂ ) may be 3 3 3 3 2 2 2 2 2 1 1 at the charging position of the 1 2 3 4 5 6 7 8 9 10 11 point of the top loading chute. After charging at the rotational speed, the slag is loaded at the rotational speed of 3 2 3 4 5 6 7 8 9 10 11 at the charging position of the top loading chute at 3 3 2 2 2 2 2 2 2 2 2 Then, the mixed layer containing slag and superfine silica sand at a weight ratio of 3: 7 is placed at the charging position of 1 2 3 4 5 6 7 8 9 10 11 point in the top loading chute 3 3 3 2 2 2 2 2 2 2 After charging with 1 rotation speed, the superfine silica sand is charged at 4 4 4 rotational speed into the charging position of 9 10 11 point of the top loading chute to complete the gas barrier charging.

Hereinafter, the operation and effects of the present invention will be described in detail.

The blocking agent may be distributed as described above at the same time as the charge reduction according to the known art, and the distribution thereof may be freely adjusted by the angle of the turning chute installed at the top of the furnace, and the surface of the charge charged during the reduction operation may be flattened. The charging distribution mode (MODE) is set in order to make the slag, and the slag and the superfine silica sand are distributed in the form of a layer stacked more in the center as shown in FIG. This is the distribution of the charges in the shape as described above due to the active inflow of furnace gas to the center during normal furnace wall repair period. Due to the deterioration of the lower vitreous silica layer, the structure is denser and the gas layer is first blocked in the semi-melt state, and the slag layer and the vitreous silica layer distributed on the upper part are radiated to the surface of the contents by the difference of the particle size and heat. Blockers penetrate through gaps in the distributed slag layer, densifying their structure. At this time, the blocker reaches the melting point between the slag by the heat of dissipation in the furnace, and the slag is not melted by the action of the different melting point blockers as shown in FIG. It is possible to block the flow of gas.

This forms a shape similar to that of a strong structure similar to that of FIG. 4, thereby completely blocking the flow of gas in the furnace to prevent deterioration of the upper furnace wall repair equipment and of course lowering the temperature of the upper surface layer of the blocker. In addition, it is possible to prevent visual disturbances in the generation of water vapor due to thermal reaction of the spray agent dropped on the surface of the blocker due to the rebound loss, and also to secure the visible distance to facilitate the observation of damaged furnace walls and to repair the furnace walls. By multiplying the furnace wall will be able to repair in a short time.

In addition, the distribution of the sealing agent applied to the surface of the charge can be freely adjusted by the angle of the swing chute installed on the top of the furnace, it is possible to add or reduce the amount if necessary from the surface of the charge.

On the other hand, as shown in Figure 3, by increasing the amount of distribution on the wall side, the amount of the rebound spray agent is biased, so that it is possible to prematurely destroy the solid part of the site during the re-blowing operation, the blocker (16) in the center By recharging, it is easily dissolved at high temperatures during re-blowing to secure the center temperature.

In addition, after refurbishment of the furnace wall, when the level (LEVEL) returned by the dry charging ore is returned to the furnace, the temperature is elevated to 1100 ° C. or higher from the tuyeres 5 installed in the lower part of the furnace. Hot air is blown into the furnace to blow air for normal operation.The barrier agent is easily dissolved even at a temperature below 600 ℃, ensuring proper pores, and the spray agent firmly attached to the barrier agent due to rebound loss is easily destroyed. In the case of hot wind and friction at high temperature, the ultra-fine silica is easily reduced and melted to secure sufficient pores so that the air permeability at the initial stage of ventilation can be achieved early as shown in FIG. do.

As can be seen from the above, according to the method of early discharge of the hard-reducing material during the repair of the furnace furnace wall of the present invention, by blocking the gas flow from the bottom of the furnace to protect the equipment from deterioration during the spray repair period, to reduce the repair time Easily observe the wear condition in the furnace to increase spray repair efficiency, and minimize the unnecessary heat dissipation of the contents inside the furnace during the furnace wall repair work to ensure stable heat retention time during normal operation after spray repair. It can be shortened. In addition, by minimizing the inflow of representative non-reducing substances from the blocker, the flow of melt in the furnace is smoothed during re-transmission, thereby eliminating the deterioration of the air permeability due to the delay of discharge, and minimizing the charging of alternative ores for smooth melt discharge. It can reduce the cost and eliminate the initial deterioration of breathability due to the initial re-blow blocker.

Although the present invention has been described in detail above, it will be apparent to those skilled in the art that various changes and modifications can be made within the spirit of the present invention, and such modifications and modifications belong to the appended claims.

Claims (3)

In the method of premature release of hard-reducing materials in the repair of furnace furnace walls, As a gas barrier agent, a superfine silica sand (SiO ₂ ) having a particle size of 2 mm or less and a melting point of 600 to 700 ° C. or a mixture of the super abrasive sand and a slag having a basicity of 1.12 or less is used. The superfine silica sand (SiO ₂ ) was charged at a rotational speed of 3 3 3 3 2 2 2 2 2 1 1 at the charging position of 1 2 3 4 5 6 7 8 9 10 11 point of the topless chute. next, After charging the slag into the charging position of 1 2 3 4 5 6 7 8 9 10 11 point of the topless loading chute at 3 3 2 2 2 2 2 2 2 2 2, The mixed layer in which the slag and the ultrafine silica sand are mixed at a weight ratio of 3: 7 is respectively placed at the charging position of 1 2 3 4 5 6 7 8 9 10 11 point of the topless chute 3 3 3 2 2 2 2 2 2 2 Charging at 1 revolution, And charging the gas barrier agent by charging the vitreous silica sand at a rotational speed of 4 4 4 at a charging position of 9 10 11 point of the top charging chute. delete delete

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