JP2007113054A - Method for charging cold-iron source into mixer car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively exhibit a heat-loss reducing effect with cold-iron source by suitably controlling the weight of the cold-iron source put into a mixer car while preventing the adverse effect on the operation. <P>SOLUTION: The cold-iron source C is put into the lower part of the opening hole part 12 of the car body 10 in the mixer car 2 during conveying to a blast furnace 1, the mixer car 2 which becomes empty by discharging molten iron in the car body 10 in the mixer car 2 into a converter facility 3, and after that, the molten iron from the blast furnace 1 is charged into the mixer car 2. Then, the weight of the cold-iron source C put into the car body 10 in the empty mixer car 2, is regulated based on the area of the opening hole part 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for charging a cold iron source into a kneading vehicle for transporting hot metal received in the blast furnace by reciprocating between the blast furnace and the converter equipment to the converter equipment.

  In a kneading vehicle that transports the hot metal received in the blast furnace back and forth between the blast furnace and the converter equipment to the converter equipment, after the discharge of the hot metal to the receiving container of the converter equipment is completed, To be returned to the blast furnace. At this time, the kneading vehicle releases the heat obtained by the hot metal before the discharge into the atmosphere, and heat loss occurs here. The heat loss causes a decrease in the temperature of the hot metal that is subsequently charged into the kneading vehicle, thereby reducing the amount of cold iron source to the hot metal blown in the converter process. An increase in the production of crude steel will be reduced, and an operation method for reducing heat loss has been proposed so far.

However, even when the above operation method is adopted, in a steelmaking facility where the blast furnace and the converter facility are separated from each other by several hundred meters to several kilometers, an empty kneading vehicle is removed from the converter facility to the blast furnace. It took a long time to return the car to the car, and this caused great heat loss from the chaotic car.
In order to solve such a problem, there has been proposed a method of operating a kneading vehicle in which a cold iron source is placed in a kneading vehicle that has finished dispensing hot metal (see, for example, Patent Documents 1 to 3).
In the operation method of the chaotic vehicle, by placing the cold iron source in the chaotic vehicle after the molten iron is discharged, the heat radiation from the chaotic vehicle is absorbed by the cold iron source, and thereby the heat radiation is released into the atmosphere. It is possible to reduce the heat loss without being recovered, and further, the chances of charging the cold iron source into the hot metal before blowing is increased, thereby reducing the hot metal mixture ratio (HMR) of the entire operation. .
JP 54-142216 A Japanese Patent No. 2852295 JP-A-5-59421

In the above Patent Documents 1 to 3, the weight of the cold iron source to be placed is about 10% of the weight of the received iron for the purpose of dissolving all of the previously placed cold iron source by receiving from the blast furnace. It is prescribed.
However, as a result of actual work, specifying the weight of the cold iron source to be placed only from the received weight may result in excessive cold iron source. In some cases, the effect of reducing the heat loss of the cold iron source cannot be fully exhibited, and the operation is adversely affected.

  Accordingly, the present invention provides a chaotic vehicle capable of effectively exhibiting the heat loss reduction effect of the cold iron source by making the weight of the cold iron source placed in the chaotic vehicle appropriate while preventing adverse effects on the operation. The purpose is to provide a method for supplying cold iron to the house.

In order to achieve the above object, the present invention takes the following technical means.
That is, the first technical means for solving the problems in the present invention is:
The molten iron in the kneading car is discharged to the converter facility, and while the empty kneading car is transported to the blast furnace, a cold iron source is placed below the furnace port of the kneading car, and then the kneading car is fed from the blast furnace. In the method of supplying cold iron to a chaotic car that is supposed to be filled with hot metal,
The weight of the cold iron source placed in the empty chaotic vehicle satisfies the expressions (1) and (2).

It is known that the heat loss in the chaotic vehicle is mainly due to external heat radiation from the surface of the chaotic vehicle and heat radiation from the furnace port.
In the operation method of the chaotic vehicle according to the present invention, a cold iron source is placed in the chaotic vehicle, and the heat that is originally released by external heat dissipation is absorbed in the cold iron source, thereby the heat in the chaotic vehicle is absorbed. The release to the outside is suppressed. Here, the amount of heat released by the external heat dissipation varies depending on the size of the area of the furnace port of the kneading vehicle, for example, as the area of the furnace port of the kneading vehicle increases, the heat dissipation from the furnace port increases, The amount of heat in the chaotic vehicle is relatively small, and the amount of heat dissipated by the external heat radiation is also small. The inventors of the present application focused on this point and repeated experiments on the area of the furnace opening and the weight of the cold iron source placed in the chaotic car. As a result, if the weight of the cold iron source to be kept is within the range of the following formula (1A), the dissipated heat due to external heat dissipation is sufficiently absorbed by the cold iron source that is kept, and consequently the heat loss of the cold iron source It was discovered that the reduction effect was fully demonstrated.

The stored cold iron source is preheated by receiving radiant heat from the inner wall of the kneading car, and when the temperature of the inner wall surface and the surface of the cold iron source become equal, the cold iron source and the air in the kneading car are The heat transfer between them is in an equilibrium state. For this reason, the inside of the chaotic vehicle is kept warm by the preheated cold iron source, and this also reduces the heat loss of the chaotic vehicle.
On the other hand, in order to suppress heat dissipation through the furnace port, the surface of the inner wall of the kneading car, especially the area directly under and around the furnace port, is covered with a cold iron source, and the radiant heat released from these surfaces to the outside of the kneading car through the furnace port. It is effective to suppress this. As a result, the temperature immediately below and around the furnace port is lowered, and the release of radiant heat directly below and around the furnace port, which is indicated by the Stefan-Boltzmann law, is suppressed.

  In general, the cold iron source to be placed is put into the kneading vehicle by a known means and is deposited below the furnace port of the kneading vehicle. As a result of repeated experiments regarding the weight of the iron source, even when the cold iron source is put into the kneading vehicle by a known means by setting the weight of the cold iron source within the range of the following formula (1B), it is directly under the furnace port. And its surroundings can be covered with a cold iron source.

Therefore, when prescribing the weight of the cold iron source to be kept for the purpose of reducing the heat loss of the chaotic vehicle, by setting the weight of the cold iron source within a range satisfying the above formula (1), Therefore, the heat loss reduction effect of the cold iron source can be sufficiently exerted against the heat radiation.
Further, if the cold iron source is excessively placed in the hot metal received by the kneading wheel, the cold iron source remains undissolved and the temperature of the hot metal becomes remarkable. Thereby, there is a possibility that the metal will adhere to the inner wall of the kneading vehicle and the remarkable temperature drop of the hot metal may hinder the subsequent operation.

Therefore, the inventor of the present application examined in detail the operation results regarding the weight of the cold iron source to be placed and the weight of the hot metal to be received. As a result, by setting the weight of the cold iron source to be put in the range of the above formula (2), it is possible to dissolve all of the cold iron source and to prevent a significant temperature drop of the hot metal received. Know that you can.
Therefore, by making the weight of the cold iron source to be placed satisfy the above formulas (1) and (2), the effect of reducing the heat loss of the cold iron source to be left can be sufficiently exhibited, and The operation after putting the source in place can be improved.

The second technical means for solving the problems in the present invention is:
The molten iron in the kneading car is discharged to the converter facility, and while the empty kneading car is transported to the blast furnace, a cold iron source is placed below the furnace port of the kneading car, and then the kneading car is fed from the blast furnace. In the method of charging the cold iron source to the kneading car, the hot metal is charged and the hot metal received is discharged to the converter equipment while the hot metal is dephosphorized.
The weight of the cold iron source placed in the empty chaotic vehicle satisfies the expressions (1) and (3).

According to the above operating method, the hot metal received in the kneading vehicle is dephosphorized in the kneading vehicle and then delivered to the converter facility.
In the dephosphorization treatment, generally, a gas acid (oxygen gas) and a solid acid (such as iron oxide) are simultaneously charged into the hot metal as a dephosphorization material. At this time, it is desirable to perform the treatment with a high-efficiency solid acid ratio larger than a low-efficiency gas acid ratio. However, the dephosphorization treatment with a solid acid includes an endothermic reaction, and an increase in the solid acid ratio leads to a large consumption of the amount of heat in the hot metal, which causes a significant decrease in the temperature of the hot metal.

In order to prevent such a temperature drop, it is desirable that the hot metal has a sufficient heat margin before the dephosphorization treatment. Therefore, the present inventor makes the amount of heat of the hot metal slightly deprived by the cold iron source by setting the weight of the cold iron source to be set to the above formula (3) or less. It has been found that the thermal margin of the hot metal for performing the heat treatment can be sufficiently maintained.
And by making the weight of the cold iron source to put into below Formula (3), the solid acid ratio of a dephosphorization process can be increased, and also the ratio of the low-efficiency gaseous acid can be reduced. is there.

The third technical means for solving the problems in the present invention is:
The molten iron in the kneading car is discharged to the converter facility, and while the empty kneading car is transported to the blast furnace, a cold iron source is placed below the furnace port of the kneading car, and then the kneading car is fed from the blast furnace. In the method of supplying cold iron to a chaotic car that is supposed to be filled with hot metal,
The weight of the cold iron source placed in the empty chaotic vehicle satisfies the equations (4) and (2).

  According to the above operation method, the kneading vehicle is in an empty state from the completion of the hot metal discharge to the start of putting in the cold iron source, and at this time, the heat in the kneading vehicle is released into the atmosphere as heat loss. Therefore, the inventor of the present application pays attention to the heat loss due to heat radiation from the completion of hot metal discharge to the start of putting in the cold iron source, and the time from the completion of hot metal discharge to the start of putting in the cold iron source in the above formula (1A) By introducing it as a variable, it has been found that the following formula (4A) is obtained in consideration of heat radiation from the chaotic vehicle before the cold iron source is charged.

  Further, the above formula (1B) is further examined, and the average bulk specific gravity of the cold iron source is determined when the weight of the cold iron source is defined for the purpose of covering directly under and around the furnace port with the cold iron source to be placed. I found out that it affected. From this viewpoint, by introducing the bulk specific gravity of the cold iron source as a variable into the above formula (1B), the following formula (4B) considering the properties of the cold iron source to be input is obtained.

Thus, in the above formula (4), when reducing the heat loss of the kneading vehicle by placing the cold iron source, the time from the completion of hot metal discharge to the start of placing the cold iron source and the average bulk of the cold iron source In consideration of the relationship with the specific gravity, the weight of the cold iron source to be placed will be defined as more realistic.
Furthermore, in view of this point, as a fourth technical means for solving the problems in the present invention,
The molten iron in the kneading car is discharged to the converter facility, and while the empty kneading car is transported to the blast furnace, a cold iron source is placed below the furnace port of the kneading car, and then the kneading car is fed from the blast furnace. In the method of charging the cold iron source to the kneading car, the hot metal is charged and the hot metal received is discharged to the converter equipment while the hot metal is dephosphorized.
The weight of the cold iron source placed in the empty chaotic vehicle preferably satisfies the formulas (4) and (3).

  According to the cold iron source charging method to the kneading vehicle of the present invention, the heat loss reduction effect by the cold iron source can be set with an appropriate weight of the cold iron source placed in the kneading vehicle while preventing adverse effects on the operation. Can be exhibited effectively.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
In the flow of the steelmaking process of the present embodiment, as shown in FIG. 1, the molten iron produced in the blast furnace 1 is received by the kneading wheel 2 and conveyed to the converter facility 3 by the kneading wheel 2. Here, the hot metal is subjected to a desulfurization process while being conveyed by the kneading vehicle 2, and then is discharged to the hot metal ladle 5 at the hot metal discharge place 4 of the converter 3.
Then, the hot metal discharged from the kneading wheel 2 to the hot metal ladle 5 is subjected to a demetalization process and then conveyed to the converter 6, where it is blown and processed into molten steel. The molten steel is discharged from the converter 6 to the molten steel pan 7 and then commercialized through a molten steel process (secondary refining process) and a continuous casting process.

In the flow, as described above, the kneading wheel 2 reciprocates between the blast furnace 1 and the hot metal discharge place 4 of the converter facility 3 to convey the hot metal, and the hot metal ladle 5 moves from the hot metal discharge place 4 to the converter 6. The blowing process is performed with the molten iron charged in the converter 6, and the molten steel is transferred from the converter 6 to the continuous casting process downstream of the converter equipment 3.
Here, as shown in FIG. 2, the kneading vehicle 2 of the present embodiment has a hollow barrel-shaped furnace body 10, and the furnace body 10 is disposed on a bogie carriage 11. The furnace body 10 is rotatable around an axis that faces the longitudinal direction thereof, and a furnace port 12 formed in an upper portion of the furnace body 10 is turned sideways so that hot metal in the furnace body 10 can be discharged. Yes.

In addition, the furnace body 10 is formed with an outer shell formed of an iron shell 14, and a fixed furnace refractory (refractory brick) 15 made of clay or high alumina containing an organic substance as a binder is pasted without a gap. In the vicinity of the furnace port 12, an in-furnace refractory material 15 is lined to form a refractory wall surface following the shape of the furnace port 12. An inner wall of the furnace body 10 is formed.
In the flow of the present embodiment shown in FIG. 1, a kneading wheel 2, a hot metal ladle 5, a converter 6, and a ladle ladle 7 are adopted as a transport container that moves between the processing facilities and transports the hot metal and molten steel. . These transport containers receive heat from the hot metal or molten steel that is received and become high temperature. However, the heat is released into the atmosphere before the transport container is returned from the transport destination to the transport source, and is heated here. Loss will occur.

  Particularly in the kneading vehicle 2, after the hot metal in the furnace body 10 is discharged at the hot metal discharge place 4, the casting of the blast furnace 1 is performed via the discharge place 8 that discharges slag remaining in the furnace body 10. Although it will be returned to the floor (not shown), it takes about 70 minutes from the hot metal discharge place 4 to the first return line L1 arriving at the discharge place 8 to digest at the discharge place 8. Since it takes about 30 minutes for the work to remove the slag, it takes about 130 minutes to digest the second return line L2 that starts at the waste disposal site 8 and arrives at the blast furnace 1. As shown in FIG. 3, the heat loss of the kneading vehicle 2 is larger at each stage than the heat loss from other transport containers.

Therefore, as shown in FIG. 1, in the present embodiment, in order to place the cold iron source shown in FIG. A cold iron source charging facility 9 is provided at the starting point.
In the present embodiment, the cold iron is used as the cold iron source C.
Here, in the 1st return line L1, the surface of the furnace refractory 15 which forms the inner wall of the kneading vehicle 2 is covered with the slag which remains in the furnace body 10 of the kneading vehicle. The slag becomes a film (insulation lid) to minimize heat radiation from the surface of the refractory 15 in the furnace. For this reason, the cold iron source C is placed immediately after completion of the waste disposal process at the waste disposal site 8 which is the starting point of the second return line L2.

And by putting the cold iron source C in the furnace body 10 which has completed the above-described exhausting process, the heat dissipation from the furnace body 10 is absorbed by the cold iron source C, thereby reducing the heat loss from the kneading vehicle 2. Reduction will be achieved.
By the way, it is known that the heat loss of the kneading vehicle 2 is mainly due to the heat radiation from the iron shell 14 and the release of the heat in the furnace body 10 from the furnace port 12. Here, the present inventors have found that the release of heat in these two paths is effectively suppressed by defining the weight of the cold iron source C to be placed.

  First, for the heat radiation from the iron shell 14, the heat in the furnace body 10 is absorbed by the cold iron source C, and the heat radiation is suppressed by the preheating effect of the cold iron source C. That is, the heat in the furnace body 10 to be released from the iron skin 14 is absorbed by the cold iron source C to be stored, and the cold iron source C is preheated by the heat. Then, heat radiation (radiant heat) from the preheated cold iron source C is received by the inner wall of the furnace body 10. Thereby, in the furnace body 10, it forms in the thermal equilibrium state between the cold iron source C and the inner wall of the furnace body 10, and the thermal insulation state in this furnace body 10 is maintained, As a result, the inner wall of the furnace body 10 The temperature decreases, and the temperature of the iron skin 14 also decreases due to heat transfer. As a result, the amount of heat released from the iron skin 14 is reduced.

At this time, as the area of the furnace port 12 increases, the amount of heat released from the furnace port 12 in the furnace body 10 increases, so the amount of heat in the furnace body 10 decreases. That is, the amount of heat in the furnace body 10 of the kneading vehicle 2 depends on the area of the furnace port 12, and accordingly, the weight of the cold iron source C to be placed also varies depending on the area of the furnace port 12. .
The inventors of the present application have found that the weight of the cold iron source C to be placed varies linearly with respect to the area of the furnace port 12. In addition, when the area A of the furnace port 12 is 1.8 m ² , even if a cold iron source C of 25 tons or more is placed, the surface temperature value of the cold iron source C reaches a peak, and the cold iron further exceeds that. When the amount of the source C is increased, the preheating effect accompanying the increase is hardly recognized, and when the area A of the furnace port 12 is set to 3.0 m ² , a cold iron source C of 23 tons or more is left in place. However, the value of the surface temperature of the cold iron source C reached a peak, and even if the amount of the cold iron source C was increased further, the preheating effect associated with the increase could hardly be recognized.

  Thereby, the following relationship is established between the weight of the cold iron source C to be placed and the area of the furnace port 12 of the furnace body 10, thereby effectively exerting the preheating effect of the cold iron source C to be placed. Thus, it has been found that the amount of heat released from the iron skin 14 of the kneading vehicle 2 can be reduced.

On the other hand, by covering the surface of the in-furnace refractory 15 in the furnace body 10, particularly the surface of the in-furnace refractory 15 immediately below and around the furnace port 12 with the cold iron source C, the inside of the furnace body 10 is covered. The release of heat from the furnace port 12 is reduced. As a result, the temperature immediately below and around the furnace port 12 decreases, and the release of radiant heat from the refractory 15 in and around the furnace port 12 indicated by Stefan-Boltzmann's law is suppressed. .
When the cold iron source is placed in the furnace body 10 in this way, in this embodiment, the cold iron source C is placed in the furnace body 10 of the kneading vehicle 2 by a known means in the cold iron source charging facility 9. Although it is placed, the surface area below the furnace port 12 to be covered by the cold iron source C to be placed increases as the area of the furnace port 12 increases. That is, the area of the surface to be covered in the kneading wheel 2 depends on the area of the furnace port 12, and the weight of the cold iron source C to be placed also varies depending on the area of the furnace port 12.

  Here, when the furnace port 12 is substantially circular, the area of the furnace port 12 is proportional to the square of the radius. Further, it is considered that the volume of the cold iron source C that is sufficient to cover the lower part of the furnace port 12 (the orthographic projection surface of the furnace port 12) and the periphery thereof is proportional to the cube of the radius. As a result, the following expression (1B ′) is established.

Furthermore, when the area A of the furnace port 12 is set to 1.8 m ² , the inventors of the present application assume that the weight of the cold iron source C is 8.0 ton or less, and the cold iron source C causes the lower part of the furnace port 12 and the I found out that the surrounding area could not be covered. From this result and the above formula (1B ′), the relationship of the following formula (1B) is established between the weight of the cold iron source C to be placed and the area of the furnace port 12, so that the cold iron source to be put in place. It has been found that the inner wall of the chaotic vehicle 2 can be sufficiently covered by C.

  Therefore, by setting the weight of the cold iron source C in a range that satisfies the following formula (1), the heat loss reduction effect of the cold iron source C placed in the furnace body 10 with respect to the heat loss of the kneading vehicle 2 is reduced. It can be fully demonstrated.

FIG. 4 shows the relationship between the area of the furnace port 12 (horizontal axis: m ² ) and the weight of the cold iron source C to be placed (vertical axis: ton / car), and a range that satisfies the above formula (1). By setting the weight of the cold iron source C, the heat loss reducing effect of the cold iron source C can be effectively exhibited.
FIG. 5 shows the relationship between the weight of the cold iron source C to be placed (horizontal axis: ton / vehicle) and the heat loss reduction effect by the cold iron source C (vertical axis: Mcal). Moreover, FIG. 8 has shown the time-dependent change (horizontal axis: minutes) of the surface temperature (vertical axis: degree C) just under the furnace port of the placed cold iron source. As shown in FIG. 5 and FIG. 8, as the weight of the cold iron source C to be placed increases, the heat loss reduction effect due to the preheating of the cold iron source C and the overall heat loss reduction effect due to the heat loss reduction effect from the furnace port 12 are increased. Increase. However, the heat loss reduction effect does not have linearity, and has reached a peak with an increase in the weight of the cold iron source C to be placed.

In view of this point, the inventors of the present application have examined the relationship between the cold iron source C to be placed and the hot metal received by the kneading wheel 2 in which the cold iron source C is placed. As a result, if the cold iron source C is placed in excess, the cold iron source C remains undissolved and the temperature drop of the hot metal becomes remarkable, and not only the heat loss reduction effect of the cold iron source C is effectively exhibited, but also the hot metal is remarkable. It has been found that there is a possibility that the subsequent operation may be hindered by a temperature drop.
Therefore, the inventor of the present application conducted an experiment on the weight of the cold iron source C to be placed and the weight of the hot metal to be received. As a result, by setting the weight of the cold iron source C to be put in the range of the following formula (2), it is possible to dissolve all the cold iron source C and prevent a significant temperature drop of the hot metal. I find out what I can do.

Therefore, by making the weight of the cold iron source C to be placed satisfy the above formulas (1) and (2), the operation after the cold iron source C is placed is not hindered, and the The heat loss reduction effect of the cold iron source C is effectively exhibited.
Further, in the steel making process, as shown in FIG. 1, after the hot metal is desiliconized in the cast floor, the kneading wheel 2 for conveying the hot metal is moved toward the converter facility 3, and the kneading wheel 2 is moved. It is also possible to adopt a configuration in which the hot metal in the furnace body 10 is subjected to a demetalization process, a dephosphorization process and a desulfurization process in the middle of the movement.

In this case, in the dephosphorization treatment, gaseous acid (oxygen gas) and solid acid (iron oxide) are charged into the molten iron as a dephosphorizing material. The reaction with the gaseous acid is an exothermic reaction, and there is no possibility that the temperature of the hot metal is lowered. However, since the treatment with gas acid is inefficient, a large amount of oxygen gas must be blown into the furnace body 10, and as a result, the carbon in the hot metal required as a heat source for the blowing process in the converter 6. May be consumed more than necessary as carbon dioxide (CO _x ) by reaction with gaseous acid. In addition, there is a risk that the refractory 15 in the furnace of the kneading vehicle 2 may be damaged at an early stage by burning the reactant due to the reaction or removing the reactant adhering to the refractory 15 in the furnace by spitting. .

For this reason, it is desirable to perform the dephosphorization treatment with a solid acid ratio larger than a gas-acid ratio. However, the dephosphorization treatment with solid acid is an endothermic reaction as a whole, and when the solid acid ratio is increased, a large amount of heat is consumed in the hot metal, which causes a significant decrease in the temperature of the hot metal.
In order to prevent such a temperature drop, it is desirable that the hot metal has a sufficient heat margin before the dephosphorization treatment. Therefore, the inventor of the present application sets the weight of the cold iron source C to be equal to or less than the following formula (3), so that the amount of heat of the hot metal is partially deprived by the cold iron source C. It has been found that the thermal margin of hot metal for dephosphorization treatment can be sufficiently maintained.

By setting the weight of the cold iron source placed in the range of the above formula (3), it is possible to increase the solid acid ratio in the dephosphorization process. Thereby, not only can the ratio of the gas acid (heat raising material) be reduced, but also the suppression of carbon dioxide emission by the dephosphorization process, the improvement of the productivity of the converter 6, the furnace body 10 of the kneading vehicle 2, and the like. The service life is extended.
By the way, in the present embodiment, although the time required for the first return line L1 is about 70 minutes, the time varies depending on the amount of hot metal supplied from the blast furnace 1 and the operating condition of the converter 6. The amount of heat remaining in the furnace body 10 after the completion of the exhausting process varies depending on the time required for the first return line L1.

  The inventors of the present application have found that the heat radiation from the completion of hot metal discharge to the start of placing the cold iron source C affects the heat radiation from the iron skin 14. The present inventors have found that when the area of the furnace port 12 is constant, the weight of the cold iron source C varies linearly with respect to the time required for the first return line L1. Therefore, in the above formula (1A), the proportional constant on the right side is divided by the average time of 100 minutes in the actual operation of the time, and the time is introduced as a variable in the term, and the cold iron source C is left in place. The following formula (4A) was obtained in consideration of heat dissipation from the chaotic vehicle 2 before the operation.

In the present embodiment, the cold iron is used as the cold iron source C to be placed as described above. On the other hand, it is extremely difficult to insert hot metal ingots having the specifications as shown in FIG. 6 and coarse converter dust as the cold iron source C to be placed in view of the reduction of HMR and recycling of scrap. preferable. Even in actual operation, it is often used as a cold iron source C in which the molten metal, converter coarse dust, and the like are placed.
By the way, in the said embodiment, the refractory material 15 in the furnace directly under and around the furnace port 12 is covered by putting the cold iron source C having a weight defined by the above formula (1B) into the furnace body 10. It is supposed to be Here, when adopting as a cold iron source C in which any one or a plurality of the cold iron sources C is placed among the plural types of the cold iron sources C, the cold iron source C for covering the refractory 15 in the furnace. The weight varies depending on the average bulk specific gravity of the cold iron source C to be placed.

Therefore, the inventors of the present invention introduced the average bulk specific gravity of the cold iron source C as a variable into the above formula (1B), and the proportional constant was determined to be a general average bulk specific gravity of 3.6 in actual operation. By dividing by (ton / m ³ ), the following formula (4B) in consideration of the type of cold iron source C to be placed was obtained.

  Thereby, the following formula (4) is obtained.

In the formula (4), the weight of the cold iron source C is defined in consideration of the relationship between the time from the completion of hot metal discharge to the start of placing the cold iron source C and the bulk specific gravity of the cold iron source C. As a result, by setting the weight of the cold iron source C placed in the kneading vehicle 2 within a range satisfying the formula (4), the weight becomes more realistic.
The above formula (4) can also be used in a steelmaking process in which the hot metal in the kneading wheel 2 is dephosphorized, and the weight of the cold iron source C to be placed is set to the above formula (4) and formula. By setting to a range that satisfies (3), the effect of reducing the heat loss of the cold iron source C that is put in place even when dephosphorizing the molten iron in the kneading wheel 2 is effectively exhibited.

Hereinafter, examples will be described together with comparative examples to demonstrate the effects of the present invention.
As shown in FIG. 7, Examples 1-8 and Comparative Examples 1-7 were compared for the heat loss reduction effect of the stored cold iron source C.
Here, in Examples 1-8 and Comparative Examples 1-7, the capacity | capacitance of the chaotic vehicle 2 is set to 65 m < ³ >, and the time from the putting start of the cold iron source C to the receiving in the blast furnace 1 is unified in 130 minutes. At the same time, the hot metal temperature at the start of the blast furnace 1 is in the range of 1480 ° C to 1520 ° C, and the hot metal temperature at the time of hot metal discharge is 1280 ° C to 1380 ° C (some cases may have been reduced to about 1200 ° C in the comparative example) Each stipulates. The time required for one cycle from the start of blast furnace acceptance to the start of the next heat blast furnace acceptance was 560 minutes on average, and was in the range of 350 to 700 minutes.

Also, the area A (m ² ) of the furnace port 12 of the kneading vehicle 2, the time t (minutes) from the completion of the hot metal discharge to the placement of the cold iron source C, the hot metal received after the cold iron source C is placed. The conditions of the weight W _p (ton) and the weight W _i (ton) of the cold iron source C to be placed are set to different values in Examples 1 to 8 and Comparative Examples 1 to 7, respectively. In Comparative Example 1, the cold iron source C is not placed.
Furthermore, in Example 1 and Example 2, it is assumed that the weight of the cold iron source C to be placed satisfies at least the above formulas (1) and (2), and in Examples 3 and 4, It is assumed that the weight of the cold iron source C to be placed satisfies at least the above formulas (1) and (3), and in Examples 5 and 6, the weight of the cold iron source C to be placed is at least the above formula ( 2) and Equation (3) are satisfied, and in Example 7 and Example 8, the weight of the cold iron source C to be placed shall satisfy at least the above Equation (3) and Equation (4). .

Further, in Comparative Examples 4 and 7, and Examples 3, 4, 7, and 8, dephosphorization treatment is performed. Here, in the dephosphorization treatment, the treatment time is set to 35 minutes, the hot metal temperature after the dephosphorization treatment is defined as a range of 1280 ° C to 1320 ° C, and gaseous oxygen is blown onto the hot metal surface from the top blowing lance. At the same time, quick lime, iron ore, and converter slag are employed as dephosphorizing materials and injected into the hot metal.
In addition, as the operation results, from the surface temperature (° C.) immediately before receiving the cold iron source C located below the furnace port 12, the hot metal temperature measured at the blast furnace cast iron main body immediately after the start of receiving and the start of receiving Lowering temperature (° C) showing the temperature difference from the hot metal temperature in the kneading car after 50 minutes, the difference in temperature difference between each example with respect to Comparative Example 1 (° C), and the gaseous acid in the case where the dephosphorization treatment was performed The input amount (Nm ³ / ton) is shown.

  Moreover, when calculating the heat loss reduction effect of each example in the effect, the heat loss reduction effect includes the heat loss reduction effect (Mcal) and the heat loss reduction efficiency (%) from the furnace port 12, and the preheating of the cold iron source C. The heat loss reduction effect (Mcal) and heat loss reduction efficiency (%) from the iron skin due to the effect, and the overall heat loss reduction effect (Mcal) and heat loss reduction efficiency (%) combining these two effects are shown. Yes. Here, the heat loss reduction efficiency is the ratio of the heat loss reduction effect when the cold iron source is placed with respect to the case where the cold iron source is not placed. The definition is shown in FIG.

In addition to this, as an effect, the remaining amount of molten iron (ton) of the cold iron source C, the weight of the molten iron that has solidified and remained in the kneading wheel 2 (ton), and the in-furnace refractory provided around the furnace port 12 The damage rate (mm / heat) per process of the object 15 is shown.
As is clear from FIG. 7, in the case of Comparative Examples 2 to 7 that do not satisfy the conditions of the present invention, the low heat loss reduction effect, the low heat loss reduction efficiency (about 20%), the melting of the cold iron source C According to Examples 1 to 8 that satisfy the conditions of the present invention, one or a plurality of remaining solidified hot metal residue and early damage tendency of the in-furnace refractory 15 are observed. The effect and the heat loss reduction efficiency (about 40%) are recognized, and there is no residual melting of the cold iron source C, no residual solidified hot metal, no early damage tendency of the refractory 15 in the furnace, and the heat of the cold iron source C The loss reduction effect is effectively exhibited, and the possibility of causing trouble in other processes and the chaotic vehicle 2 is solved.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments. For example, it is possible to perform a desulfurization process after the hot metal being transported by the kneading vehicle 2 is subjected to a desulfurization process, and then to discharge the hot metal to the hot metal discharge place 4 of the converter 3.
Alternatively, it is possible to perform a dephosphorization process and a desulfurization process after the hot metal being conveyed is removed by the kneading vehicle 2 and then the hot metal is discharged to the hot metal discharge place 4 of the converter 3. is there.

It is a figure which shows the flow of a steel manufacturing process. It is a partially broken side view of a chaotic vehicle. It is a figure which shows the heat loss of a receiving container. It is a figure which shows the optimal range of the weight of the cold iron source put. It is a figure which shows a heat loss reduction effect. It is a figure which shows the specification of a cold iron source. It is a figure which compares and shows an Example and a comparative example. It is a figure which shows the time-dependent change of the surface temperature of the cold iron source put. It is a list figure which shows the definition of each heat loss reduction effect and heat loss reduction efficiency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blast furnace 2 Chaotic car 3 Converter equipment 4 Hot metal discharge place 6 Converter 8 Exhaust place 9 Cold iron source input equipment 10 Furnace 12 Furnace 14 Iron skin 15 Refractory in furnace C Cold iron source

Claims (4)

The molten iron in the kneading car is discharged to the converter facility, and while the empty kneading car is transported to the blast furnace, a cold iron source is placed below the furnace port of the kneading car, and then the kneading car is fed from the blast furnace. In the method of supplying cold iron to a chaotic car that is supposed to be filled with hot metal,
The method of putting a cold iron source into a chaotic vehicle, wherein the weight of the cold iron source placed in the empty chaotic vehicle satisfies the expressions (1) and (2).

The molten iron in the kneading car is discharged to the converter facility, and while the empty kneading car is transported to the blast furnace, a cold iron source is placed below the furnace port of the kneading car, and then the kneading car is fed from the blast furnace. In the method of charging the cold iron source to the kneading car, the hot metal is charged and the hot metal received is discharged to the converter equipment while the hot metal is dephosphorized.
The method of putting a cold iron source into a chaotic vehicle, wherein the weight of the cold iron source placed in the empty chaotic vehicle satisfies the expressions (1) and (3).

The molten iron in the kneading car is discharged to the converter facility, and while the empty kneading car is transported to the blast furnace, a cold iron source is placed below the furnace port of the kneading car, and then the kneading car is fed from the blast furnace. In the method of supplying cold iron to a chaotic car that is supposed to be filled with hot metal,
The method of putting a cold iron source into a chaotic vehicle, wherein the weight of the cold iron source placed in the empty chaotic vehicle satisfies the expressions (4) and (2).

The molten iron in the kneading car is discharged to the converter facility, and while the empty kneading car is transported to the blast furnace, a cold iron source is placed below the furnace port of the kneading car, and then the kneading car is fed from the blast furnace. In the method of charging the cold iron source to the kneading car, the hot metal is charged and the hot metal received is discharged to the converter equipment while the hot metal is dephosphorized.
The method of putting a cold iron source into a chaotic vehicle, wherein the weight of the cold iron source placed in the empty chaotic vehicle satisfies the equations (4) and (3).

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