JP5966608B2 - Raw material charging method to blast furnace - Google Patents

Description

  The present invention relates to a raw material charging method for a blast furnace in which a raw material is charged into the furnace with a turning chute.

  In a blast furnace, generally, ore raw materials such as sintered ore, pellets and massive ore and coke are charged in layers from the top of the furnace, and combustion gas flows from the tuyere to obtain pig iron. The coke and ore raw material, which are the charged raw materials for the blast furnace, descend from the top of the furnace to the lower part of the furnace, and ore reduction and raw material temperature rise occur. The ore raw material layer is gradually deformed while filling the gaps between the ore raw materials due to the temperature rise and the load from above, and the lower part of the shaft part of the blast furnace has a very high resistance to gas and almost no gas flows. Form a layer.

Conventionally, raw material charging into a blast furnace is performed by alternately charging ore raw materials and coke, and in the furnace, ore raw material layers and coke layers are alternately layered. Further, in the lower part of the blast furnace, there are an ore raw material layer having a large ventilation resistance in which an ore called a fusion zone is softened and fused, and a coke slit having a relatively small ventilation resistance derived from coke.
The air permeability of this cohesive zone has a great influence on the air permeability of the entire blast furnace, and the productivity in the blast furnace is limited. When a low coke operation is performed, it is considered that the coke slit becomes extremely thin because the amount of coke used is reduced.

In order to improve the cohesive zone ventilation resistance, it is known that mixing coke into the ore raw material layer is effective, and many studies have been reported to obtain an appropriate mixing state. .
For example, in Patent Document 1, in a bell-less blast furnace, coke is charged into the ore hopper on the downstream side of the ore hopper, the coke is stacked on the ore on a conveyor, charged into the furnace top bunker, and the ore And coke are charged into the blast furnace through a turning chute.

  In Patent Document 2, ore and coke are separately stored in a bunker at the top of the furnace, and coke and ore are mixed and charged at the same time, so that a normal coke charging batch and a coke central charging batch are used. And three batches for mixing and charging are performed simultaneously.

  Furthermore, in Patent Document 3, in order to prevent the instability of the cohesive zone shape in the blast furnace operation and the decrease in the gas utilization rate near the center, and to improve the safe operation and thermal efficiency, the raw material charging method in the blast furnace is In addition, all ore and all coke are thoroughly mixed and then charged into the furnace.

JP-A-3-211210 JP 2004-107794 A Japanese Patent Publication No.59-10402

Incidentally, in order to improve the ventilation resistance of the cohesive zone, it is known that mixing coke with the ore layer is effective as in the conventional example described in Patent Document 3 described above.
However, the average particle size of the typical coke described in Patent Document 3 is about 40 mm, and the average particle size of the ore is about 15 mm. As a result, the air permeability in the furnace deteriorates, and there is a possibility that troubles such as gas blow-through and poor lowering of raw materials may occur.
In order to avoid these troubles, a method of forming a coke-only layer in the furnace axis can be considered. According to this method, the passage of gas through the coke layer is secured in the core portion of the furnace, so that air permeability can be improved. However, when the operation is performed by blowing a large amount of pulverized coal from the tuyere as a blast furnace reducing material, the air permeability is hindered by the unburned powder of pulverized coal, and the air permeability especially around the furnace wall is greatly deteriorated. In other words, it cannot be said that it is sufficient to ensure air permeability only in the core portion of the furnace.

  The present invention has been developed in view of the above-described present situation, and even when a large amount of pulverized coal is injected, air permeability is ensured, and stabilization of blast furnace operation and improvement of thermal efficiency can be achieved. It aims at providing the raw material charging method to a blast furnace.

That is, the gist configuration of the present invention is as follows.
1. In the blast furnace operation method of charging ore raw materials such as sintered ore, pellets, massive ore and blast furnace charging raw materials of coke into the blast furnace using a rotating chute,
Upon charged the blast furnace charging material into a blast furnace, the axial center of the blast furnace, to form the only center coke layer, the furnace wall peripheral portion of the blast furnace, surrounding the coke layer alone, or near the coke layer Form a layer with a mixed layer of ore raw material and coke on the surface, and form only a mixed layer of ore raw material and coke in the region between the central coke layer and the peripheral coke layer. A method for charging raw materials into a blast furnace.

2. At least two furnace top bunkers are provided at the top of the blast furnace, and the ore raw material or the ore raw material and the coke are added to one or two of the furnace top bunkers in a total amount of 30% by mass. Either or both of the mixed raw materials mixed so as to become the following are respectively stored, the coke is stored in one of the remaining furnace top bunkers, and the raw materials discharged from each furnace top bunker are temporarily stored in the collecting hopper Then, when charging the blast furnace charging raw material in the blast furnace by supplying the swirl chute,
(1) First, the raw material charging destination of the swirl chute is the inner peripheral part of the blast furnace wall, and only the coke is discharged from the furnace bunker charged with only coke, so that the periphery of the inner peripheral part of the blast furnace wall is Forming a coke layer,
(2) Next, the material charging destination of the swivel chute is the center of the blast furnace, and only the coke is discharged from the top bunker charged with only coke, so that the central coke layer is formed in the center of the blast furnace. Form the
(3) Next, the raw material charging destination of the turning chute is between the central coke layer and the peripheral coke layer, and the coke and the ore raw material and / or the mixed raw material are discharged simultaneously from each furnace top bunker, and the collecting hopper The mixed layer of the ore raw material and the coke is formed in a region between the central coke layer and the peripheral coke layer after being mixed in The raw material charging method to the blast furnace as described in 1.

3. 3. The raw material charging method to the blast furnace according to 2 above , wherein the formation of the mixed layer of the ore raw material and the coke is extended to the surface of the peripheral coke layer .

4). 4. The raw material charging method to the blast furnace according to any one of 1 to 3, wherein the blast furnace operation is a high pulverized coal ratio operation in which pulverized coal is blown from a tuyere at 180 kg or more per 1 ton of molten iron .

  According to the present invention, when ore raw material and coke are charged into the blast furnace, a central coke layer is formed in the axial center part of the blast furnace, and a peripheral coke layer is formed in the furnace wall part of the blast furnace. Since a mixed layer in which ore raw materials and coke are mixed is formed between the coke layer and the surrounding coke layer, the air permeability in the lower part of the furnace is remarkably improved, and the reduction rate of the ore is greatly improved. Even in a situation where a large amount of unburned powder derived from pulverized coal is generated in high pulverized coal ratio operation, stable blast furnace operation can be performed.

It is a schematic diagram which shows one Embodiment of the raw material charging method to the blast furnace of this invention. It is explanatory drawing which shows the raw material discharge | emission order from a furnace top bunker. It is a schematic diagram which shows the raw material charging state containing a furnace top bunker. It is a schematic diagram which contrasts and shows the raw material charging state to the blast furnace by this invention, and the raw material charging state in a normal blast furnace. It is explanatory drawing which compares the raw material charging state into the blast furnace by this invention, and the raw material charging state in a normal blast furnace, and shows the reduction | restoration state, ventilation | gas_flowing / heat-transfer state, and a molten carburizing state of an upper part, a middle part, and a lower part. It is a schematic block diagram which shows the experimental apparatus which measures the high temperature property of an ore raw material. It is a characteristic line figure which shows the relationship between the ventilation resistance of the experimental result of the experimental apparatus of FIG. It is a characteristic diagram which shows the relationship between the mixing ratio of the coke to the ore raw material and the maximum pressure loss ratio which used the coke particle diameter as a parameter.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing an embodiment of a method for charging a raw material into a blast furnace according to the present invention.
In the figure, reference numeral 1 denotes an ore raw material hopper for storing an ore raw material 2 composed of at least one of sintered ore, pellets and massive ore, and 3 denotes a coke hopper for storing coke 4. The ore raw material 2 and the coke 4 cut out from the ore raw material hopper 1 and the coke hopper 3 at a predetermined ratio are conveyed upward by the ore conveyor 5, and the ore raw material 2 and the coke 4 are mixed with the reserve hopper 6. It is stored as a blast furnace charging raw material 7. The blast furnace charging raw material 7 cut out from the reserve hopper 6 is transferred to the furnace top of the blast furnace 10 by the charging conveyor 8, and one of a plurality of, for example, three furnace top bunkers 12 a to 12 c through the receiving chute 11, for example. It is thrown into 12b and stored. Here, the ore raw material and the coke mixed raw material stored in the furnace top bunker 12b are adjusted so that the coke amount is 30% or less of the total amount of the mixed raw material. Here, the reason for adjusting the coke amount to 30% or less of the total amount of the mixed raw material is as follows.

The ore raw material 2 and the coke 4 cut out from the ore raw material hopper 1 and the coke hopper 3 are put into the reserve hopper 6 in a state where the coke 4 is laminated on the ore raw material 2 by the ore conveyor 5. By this, the ore raw material 2 and the coke 4 are mixed by this reserve hopper 6 and become a mixed raw material. However, since the mixed raw material stored in the reserve hopper 6 is conveyed to the receiving chute 11 by the charging conveyor 8, there is a specific gravity difference and a particle size difference between the coke and the ore raw material on the charging conveyor 8. Therefore, there is a possibility of segregation, and further, there is a possibility of segregation when being introduced into the furnace top bunker 12b via the receiving chute 11.
At this time, when the amount of coke to be mixed is 30% or less of the total amount, when the coke is stored in the furnace top bunker 12b, no large segregation occurs between the coke and the ore raw material, and the swirl chute 16 forms. The mixing rate of the mixed layer of the ore raw material and coke can be made substantially uniform.

On the other hand, when the amount of coke exceeds 30% of the total amount, segregation due to difference in specific gravity and particle size is likely to occur, and segregation between coke and ore raw material becomes large when stored in the furnace top bunker 12b, A region where only the ore raw material or only the coke exists locally is generated.
Moreover, as shown in FIG. 2, the discharging order when discharging the mixed raw material from the furnace top bunker 12b is sequentially moved upward from a position close to the discharge port 12g close to the central axis of the blast furnace, and thereafter from the central axis of the blast furnace. It moves in the direction away from the outside, and finally the upper end side of the inclined side wall 12h is discharged.

  For this reason, when only the ore raw material or only the coke is present immediately above the discharge port 12g or the upper end side of the inclined side wall 12h, only the ore raw material or only the coke is discharged. 14 is mixed with the coke and ore raw materials discharged from the other top bunker 12a and 12c, but the ratio of the ore raw material or the coke is increased and the ores formed by the swivel chute 16 are mixed. The mixing ratio of the raw material and coke mixed layer becomes non-uniform.

Next, a specific charging procedure for charging the ore raw material and coke into the blast furnace will be described with reference to FIG.
In this example, the ore raw material and coke mixed raw material are stored in the furnace top bunker 12b, only the coke is stored in the furnace top bunker 12a, and only the ore raw material is stored in the furnace top bunker 12c. Yes.
Further, the turning chute 16 is rotated about the shaft center of the blast furnace 10 and at the same time is reversely tilted to tilt toward the furnace wall side from the shaft center portion of the blast furnace 10. The case of performing will be described.
Furthermore, the case where a center coke layer is formed in the axial center part of a blast furnace is demonstrated.

As the raw material charging sequence from the furnace top bunker, first, the raw material charging destination of the swivel chute 16 is set to the inner peripheral portion of the furnace wall of the blast furnace, and only the coke is discharged from the furnace top bunker 12a charged with only coke. Thus, the peripheral coke layer 12f is formed on the inner peripheral portion of the furnace wall of the blast furnace.
That is, in a state where the raw material charging destination of the turning chute 16 faces the furnace wall portion of the blast furnace, the flow rate adjusting gates 13 of the furnace top bunkers 12b and 12c are closed, and the flow rate adjusting gate 13 of only the furnace top bunker 12a is opened. By supplying only the coke stored in the furnace top bunker 12a to the turning chute 16, as shown in FIG. 3, a peripheral coke layer 12f is formed on the inner peripheral portion of the blast furnace wall.

At this time, the dropping position of the charged raw material at the height of the raw material stock line is desirably 0.7 or more and 1.0 or less in the dimensionless radius of the blast furnace where the blast furnace shaft center part is 0 and the furnace wall part is 1. . The reason is that the air permeability around the furnace wall can be effectively improved by collecting the coke as much as possible around the furnace wall. If the dropping position of the charged raw material is smaller than the dimensionless radius of 0.7, coke flows from the middle part to the center part, and the coke layer on the furnace wall part may not function sufficiently.
Note that the amount of coke charged to form the peripheral coke layer is preferably about 20 to 40% by mass of the amount of coke charged per charge. This is because if the amount of coke charged to the furnace wall is less than 20% by mass, the air permeability around the furnace wall is not sufficiently improved, while more than 40% by mass of coke is concentrated on the furnace wall. In this case, not only the amount of coke to be used for the mixed layer and the central coke layer is decreased, but also the amount of heat removed from the furnace body is increased due to excessive gas flow in the periphery.

Next, the raw material charging destination of the turning chute 16 is the blast furnace axial center, and only the coke is discharged from the furnace top bunker 12a in which only the coke is charged, whereby the central coke layer 12d is formed in the central part of the blast furnace. Form.
That is, in a state where the turning chute 16 is tilted in a substantially vertical state, the flow rate adjustment gates 13 of the furnace top bunkers 12b and 12c are closed, the flow rate adjustment gate 13 of only the furnace top bunker 12a is opened, and the furnace top bunker 12a By supplying only the stored coke to the turning chute 16, as shown in FIG. 3, a central coke layer 12d is formed in the axial center portion.
The amount of coke charged to form the central coke layer is preferably about 10 to 30% by mass of the amount of coke charged per charge. This is because if the amount of coke charged into the shaft center part is less than 10% by mass, the air permeability around the shaft center part is not sufficiently improved, while more than 30% by mass coke is concentrated on the shaft center part. In this case, not only the amount of coke to be used for the mixed layer and the peripheral coke layer is decreased, but also the amount of heat extracted from the furnace body is increased due to excessive gas flow in the axial center.

Subsequently, the raw material charging destination of the turning chute 16 is between the central coke layer and the peripheral coke layer, and the coke and the ore raw material and / or the mixed raw material are discharged simultaneously from each furnace top bunker and mixed by the collecting hopper 14. After that, by supplying the swirl chute 16, a mixed layer 12e of ore material and coke is formed in a region between the central coke layer 12d and the peripheral coke layer 12f.
That is, when the raw material charging destination of the turning chute is between the central coke layer and the peripheral coke layer, not only the furnace top bunker 12a but also the flow rate adjustment gates 13 of the remaining two furnace top bunkers 12b and 12c are provided. The coke discharged from the furnace top bunker 12a, the mixed raw material discharged from the furnace top bunker 12b, and the ore raw material discharged from the furnace top bunker 12c are simultaneously supplied to the collecting hopper 14, The coke and the ore raw material are thoroughly mixed by the collecting hopper 14 and then supplied to the turning chute 16. As a result, in the region between the central coke layer 12d and the peripheral coke layer 12f in the blast furnace 10, the coke and the ore raw material have a substantially uniform mixing ratio, and a mixed layer 12e that does not generate a coke slit is formed. .
In addition, although the ratio of the coke in the mixed layer 12e is based also on the quantity of the center coke layer 12d and the peripheral coke layer 12f, it is preferable to set it as about 20-50 mass% of the total coke amount.

  In the present invention, as shown in FIG. 3, the mixed layer 12e is formed not only in the region between the central coke layer 12d and the peripheral coke layer 12f but also extending to the surface of the peripheral coke layer 12f. You can also.

Then, the layers composed of the peripheral coke layer 12f, the central coke layer 12d, and the mixed layer 12e are sequentially formed in the blast furnace 10 from the bottom to the top.
In this way, by sequentially laminating the layers composed of the peripheral coke layer 12f, the central coke layer 12d, and the mixed layer 12e, the central coke layer 12d having a low ventilation resistance is formed in the axial center portion and the furnace wall portion in the blast furnace 10. The peripheral coke layer 12f is formed from the blast furnace lower part toward the blast furnace upper part, and the mixed layer 12e in which the coke and the ore raw material are completely mixed is formed therebetween.

Therefore, as shown in the right half of FIG. 4, the central coke of the shaft center portion is caused by flowing high temperature gas mainly composed of CO from the tuyere blast pipe 17 provided in the hot water reservoir in the lower part of the blast furnace 10. A rising gas flow is formed through the layer 12d and the peripheral coke layer 12f, and a rising gas flow is formed through the mixed layer 12e. Coke is burned by the high-temperature gas flowing in from the blower pipe 17, and the ore raw material is reduced and dissolved.
In FIG. 4, 18 is a coke layer in the conventional charging system, 19 is an ore layer, 20 is an ore / coke mixed layer, 21 is a cohesive zone (ore softening layer), and 22 is a gas flow. Indicates.

As a result, the ore raw material in the lower part of the blast furnace 10 is melted, so that the coke and the ore raw material charged in the blast furnace 10 descend from the top of the furnace to the lower part of the furnace, and the reduction of the ore raw material and the ore The temperature of the raw material is raised.
For this reason, a fusion zone in which the ore material is softened is formed on the upper side of the molten layer, and the ore material is reduced on the upper side of the fusion zone.
At this time, as shown in the right half of FIG. 5, in the lower part of the blast furnace 10, the ore raw material and the coke are completely mixed in the mixed layer 12e, and the coke enters between the ore raw materials. Since there is no slit, the air permeability is improved and the high-temperature gas passes directly between the ore raw materials, so there is no heat transfer delay and the heat transfer characteristics can be improved.

For this reason, in the lower part of the cohesive zone of the blast furnace 10, the contact area between the ore raw material and the high temperature gas is expanded, and carburization can be promoted. Further, in the cohesive zone, air permeability and heat transfer can be improved. Furthermore, since the ore raw material and coke are arranged close to each other in the upper part of the blast furnace 10, the coupling is a mutual activation phenomenon between the reduction reaction of the ore raw material and the gasification reaction (carbon solution loss reaction). Good reduction is performed without causing a reduction delay due to the reaction.
The reduction reaction at this time is represented by FeO + CO = Fe + CO ₂ .
The gasification reaction is represented by C + CO ₂ = 2CO.

  On the other hand, in the conventional example in which the ore and coke described above are laminated in layers, as shown in the left half of FIG. 4, the ore and coke are alternately charged in the blast furnace, and the ore layer and coke are placed in the blast furnace. The layers are charged in layers. In this case, when high temperature gas mainly composed of CO is introduced from the tuyere blast pipe 21, the ventilation is restricted by the reduction of the coke slit at the lower part of the cohesive zone as shown in the left half of FIG. As the pressure loss increases, there is a problem that the contact area of the ore with the hot gas is reduced and carburization is limited.

In addition, a coke slit is formed on the upper side of the cohesive zone, and heat conduction is mainly conducted to the ore through the coke slit, so that a heat transfer delay occurs and heat transfer is insufficient, and in the upper part of the blast furnace 10, Since the coke layer with good air permeability and the ore layer with poor air permeability are laminated, not only the rate of temperature increase is reduced, but only the reduction reaction is performed and the above coupling reaction cannot be expected. There is a problem that occurs.
However, in the present embodiment, as described above, the charging layer formed by the coke-only central coke layer 12d, the peripheral coke layer 12f, and the mixed layer 12e in which coke and ore raw materials are completely mixed is laminated. Therefore, coke slits are not formed in the mixed layer 12e, the gas flow is made uniform, good heat transfer is ensured, and stable ventilation can be improved, thereby solving the problems of the conventional example. be able to.

In order to verify the above effect of the present embodiment, using the experimental apparatus shown in FIG. 6, changes in the ventilation resistance were investigated by simulating the raw material reduction and temperature rising processes in the blast furnace.
In this experimental apparatus, a furnace core tube 32 is disposed on the inner peripheral surface of a cylindrical furnace body 31, and a cylindrical heating heater 33 is disposed outside the furnace core tube 32. A graphite crucible 35 is disposed at the upper end of a cylindrical body 34 made of a refractory inside the furnace core tube 32, and a charging raw material 36 is charged into the crucible 35. A load is applied to the charged raw material 36 from above by a load loading device 38 connected via a punch bar 37 so as to be in the same level as the fused layer at the bottom of the blast furnace. A drop sampling device 39 is provided below the cylindrical body 34.

The gas adjusted by the gas mixing device 40 is sent to the crucible 35 through the lower cylindrical body 34, and the gas that has passed through the charging material 36 in the crucible 35 is analyzed by the gas analyzer 41. The heating heater 33 is provided with a thermocouple 42 for controlling the heating temperature, and the crucible 35 is set to 1200 to 1500 by controlling the heater 33 with a control device (not shown) while measuring the temperature with the thermocouple 42. Heat to ° C.
Here, as the ore of the charging raw material 36 charged in the crucible 35, a mixture of 50 to 100% by mass of sintered ore and 0 to 50% by mass of massive iron ore was used.

FIG. 7 is a characteristic diagram showing the relationship between the ventilation resistance and the heating temperature when the amount of coke mixed with ore showing an example of the experimental results of the experimental apparatus is changed.
As shown in FIG. 7, when the coke is not mixed, the ventilation resistance rapidly increases in a high temperature range of 1300 ° C. or higher, whereas when the coke is mixed, the ventilation resistance is remarkably reduced. At this time, it can be seen that the effect increases when the amount of coke mixed is increased. This is because the mixing of coke suppresses the deformation of the ore and maintains the voids in the vicinity of the mixed coke. This is to prevent this.

FIG. 8 is a characteristic diagram showing the relationship between the coke mixing ratio and the maximum pressure loss ratio when the coke sizes are different.
As shown in FIG. 8, in the case of using a lump coke and a small lump coke, the ventilation resistance values in the fusion layer are different, and when a small lump coke is used, the lump coke is used. In comparison, it was demonstrated that the pressure loss was reduced even with the same mixing amount.
Here, the lump coke means a particle having a particle size of about 30 to 60 mm, and the small and medium lump coke means a particle having a particle size of about 10 to 30 mm. On the other hand, the ore raw material usually has a particle size of about 5 to 20 mm.

In addition, the inventors investigated the ratio of coke in the mixed layer suitable for reduction of pressure loss, that is, improvement of air permeability (amount of coke / amount of ore raw materials), and a mass ratio of about 7 to 25% is preferable. There was found. More preferably, it is 10 to 15% of range.
Conventionally, the amount of coke required for producing hot metal: 1 ton (kg), that is, the coke ratio was about 350 to 380 kg / t. However, when the raw material is charged according to the present invention, the coke ratio is 300. It is possible to reduce to about ~ 330 kg / t.

When coke is not mixed in the ore layer at all (Comparative Example 1), 70% by mass of coke is mixed in the ore layer, and the remaining 30% by mass is disposed in the blast furnace core (Comparative Example 2). When the remaining coke is 20% in the axial center part of the blast furnace and 20% in the inner peripheral part of the furnace wall (Invention Example 1), the pulverized coal ratio: 180 kg / t high pulverized coal ratio The operation was performed. It should be noted that the output ratio, which is a value obtained by dividing the amount of tapping per day (t / d) of the blast furnace by the volume (m ³ ) of the furnace, was 2.0 in all cases.
The operation results in each case are shown in comparison with Table 1.

In Table 1, the coke ratio and the pulverized coal ratio are the amount of coke and the amount of pulverized coal (kg) used when producing hot metal 1t.
The reducing material ratio is the sum of the coke ratio and pulverized coal ratio.
The gas utilization rate is a ratio of the concentration of CO ₂ and CO at the top of the furnace, and is calculated by the following equation.
Gas utilization rate = CO ₂ / (CO ₂ + CO) × 100
Here, CO ₂ is the furnace top CO ₂ concentration [%]
CO is furnace top CO concentration [%]
ΔP / V is an index obtained by indexing the ventilation resistance in the blast furnace, and is calculated by the following equation.
ΔP / V = (BP−TP) / BGV
Here, BP is the blowing pressure [Pa].
TP is the furnace top pressure [Pa]
BGV is Bosch gas amount [m ³ (standard state) / min]

As shown in Table 1, although Comparative Example 2 is improved as compared with Comparative Example 1, the gas utilization rate does not improve much, and the amount of increase in pulverized coal is larger than the amount of reduction in coke ratio. As a result, the ratio of reducing materials was inevitably increased. Furthermore, in Comparative Example 2, it was possible to grasp in advance the deterioration of the unloading of the raw material and the gas blow-off by the sign of the pressure fluctuation of the shaft portion, but since the amount of pressure fluctuation increased, from the viewpoint of maintaining the operation, the coke ratio It was forced to increase.
On the other hand, the invention example 1 did not generate shaft pressure fluctuations even under high pulverized coal ratio operation, the gas utilization rate was greatly improved, and the coke ratio could be greatly reduced. For this reason, although the pulverized coal ratio is increased, the overall reducing material ratio has been successfully reduced.

1 Ore Powder Hopper 2 Ore Raw Material 3 Coke Hopper 4 Coke 5 Ore Conveyor 6 Reserving Hopper 7 Blast Furnace Charge Raw Material 8 Charge Conveyor 10 Blast Furnace 11 Receiving Chute 12a-12c Top Bunker 12d Central Coke Layer 12e Mixed Layer 12f Around Coke layer 12g Furnace top bunker outlet 12h Inclined side wall of furnace top bunker 13 Flow control gate 14 Collecting hopper 15 Bellless charging device 16 Turning chute 17 Blow pipe 18 Coke layer 19 Ore layer 20 Ore / coke mixed layer 21 Fusion Zone (Ore softening layer)
22 Gas flow

Claims (4)

In the blast furnace operation method of charging ore raw materials such as sintered ore, pellets, massive ore and blast furnace charging raw materials of coke into the blast furnace using a rotating chute,
Upon charged the blast furnace charging material into a blast furnace, the axial center of the blast furnace, to form the only center coke layer, the furnace wall peripheral portion of the blast furnace, surrounding the coke layer alone, or near the coke layer Form a layer with a mixed layer of ore raw material and coke on the surface, and form only a mixed layer of ore raw material and coke in the region between the central coke layer and the peripheral coke layer. A method for charging raw materials into a blast furnace. At least two furnace top bunkers are provided at the top of the blast furnace, and the ore raw material or the ore raw material and the coke are added to one or two of the furnace top bunkers in a total amount of 30% by mass. Either or both of the mixed raw materials mixed so as to become the following are respectively stored, the coke is stored in one of the remaining furnace top bunkers, and the raw materials discharged from each furnace top bunker are temporarily stored in the collecting hopper Then, when charging the blast furnace charging raw material in the blast furnace by supplying the swirl chute,
(1) First, the raw material charging destination of the swirl chute is the inner peripheral part of the blast furnace wall, and only the coke is discharged from the furnace bunker charged with only coke, so that the periphery of the inner peripheral part of the blast furnace wall is Forming a coke layer,
(2) Next, the material charging destination of the swivel chute is the center of the blast furnace, and only the coke is discharged from the top bunker charged with only coke, so that the central coke layer is formed in the center of the blast furnace. Form the
(3) Next, the raw material charging destination of the turning chute is between the central coke layer and the peripheral coke layer, and the coke and the ore raw material and / or the mixed raw material are discharged simultaneously from each furnace top bunker, and the collecting hopper Then, a mixed layer of ore raw material and coke is formed in a region between the central coke layer and the peripheral coke layer.
The raw material charging method to the blast furnace according to claim 1. The method of charging a raw material into a blast furnace according to claim 2, wherein the formation of the mixed layer of the ore raw material and the coke is extended to the surface of the peripheral coke layer. The method for charging raw materials into a blast furnace according to any one of claims 1 to 3, wherein the blast furnace operation is a high pulverized coal ratio operation in which pulverized coal is blown from a tuyere at 180 kg or more per 1 ton of molten iron.

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