WO2021152989A1 - Method for charging raw material into blast furnace - Google Patents

Method for charging raw material into blast furnace Download PDF

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Publication number
WO2021152989A1
WO2021152989A1 PCT/JP2020/044357 JP2020044357W WO2021152989A1 WO 2021152989 A1 WO2021152989 A1 WO 2021152989A1 JP 2020044357 W JP2020044357 W JP 2020044357W WO 2021152989 A1 WO2021152989 A1 WO 2021152989A1
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Prior art keywords
ore
mixed
coke
coarse
furnace
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PCT/JP2020/044357
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French (fr)
Japanese (ja)
Inventor
和平 市川
佐藤　健
山本　哲也
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Ｊｆｅスチール株式会社
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Application filed by Ｊｆｅスチール株式会社 filed Critical Ｊｆｅスチール株式会社
Priority to CN202080094945.8A priority Critical patent/CN115023508B/en
Priority to JP2021508006A priority patent/JP6885528B1/en
Priority to KR1020227026245A priority patent/KR20220119154A/en
Priority to BR112022014972A priority patent/BR112022014972A2/en
Priority to EP20916867.3A priority patent/EP4083235A4/en
Publication of WO2021152989A1 publication Critical patent/WO2021152989A1/en

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B5/00—Making pig-iron in the blast furnace

Definitions

  • the present invention relates to a method of charging raw materials into a blast furnace.
  • the ore and coke which are the raw materials, are alternately charged from the top of the furnace in predetermined amounts, and the ore layer and the coke layer are alternately laminated in the furnace.
  • This layer of ore and coke is called one charge of ore and coke, respectively.
  • the gas flow in the furnace is controlled by controlling the layer thickness ratio of the ore layer and the coke layer in the furnace in the furnace radial direction.
  • the charging chute is tilted during charging of raw materials in order to realize stable blast furnace operation and form a layer thickness ratio distribution that can reduce the reducing agent ratio. The corners are changed as appropriate.
  • the ore and coke of each charge are charged in batches a plurality of times.
  • Non-Patent Document 1 discloses that the ratio of reducing agent in blast furnace operation can be reduced by mixing 50 kg / t-pi small coke in the ore layer.
  • Patent Document 1 states that the first batch when the ore layer is divided into two batches is a mixture of ore and coke, and the first half of the mixture is a charging chute as a furnace wall.
  • a method is disclosed in which a forward tilting charge is used in which the charge is tilted from the side to the center side of the furnace, and a reverse tilt charge is used in which the charge is tilted from the center side of the furnace to the furnace wall side in the latter half.
  • the coke mixing ratio is controlled by charging in this way, and the reducing property of the ore can be improved by this.
  • Patent Document 2 discloses a method in which small coke is mixed with ore charged in the vicinity of the center of the furnace and then charged in a forward tilted manner.
  • Non-Patent Document 2 discloses a method of classifying the sinter and charging coarse particles on the center side and fine particles on the peripheral side of the blast furnace.
  • the present invention has been made in view of such problems of the prior art, and an object of the present invention is a coarse-grained ore mixed with mixed coke that maintains high reduction reactivity while ensuring air permeability in a blast furnace. It is to provide a method of charging raw materials into a blast furnace capable of forming a layer.
  • the means for solving the above problems are as follows. (1) A method of charging raw materials into a blast furnace in which a mixture of ore and mixed coke is divided into two or more batches using a bellless charging device having a charging chute and charged into the blast furnace. It is divided into coarse-grained ore and fine-grained ore having an average particle size smaller than that of the coarse-grained ore, and mixed coke is mixed with the coarse-grained ore to obtain a coarse-grained ore in which mixed coke is mixed.
  • the mixed coke is mixed to form a fine-grained ore in which the mixed coke is mixed, and the charging chute is made from the furnace center side to the furnace wall side of the midpoint between the furnace center and the furnace wall in the radial direction of the blast furnace in at least the first batch.
  • a method for charging a raw material into a blast furnace in which all or a part of the coarse-grained ore mixed with the mixed coke is charged by tilting.
  • the charging chute is tilted from the furnace wall side to the furnace center side from the midpoint between the furnace center and the furnace wall in the radial direction of the blast furnace, and the mixed coke is mixed in the fine-grained ore.
  • the method for charging raw materials into a blast furnace according to (1), wherein all or part of the material is charged.
  • the coarse-grained ore mixed with the mixed coke is suppressed from flowing into the furnace center side, and the coke is suppressed from segregating toward the furnace center side. ..
  • a coarse-grained ore layer mixed with mixed coke that maintains high reduction reactivity while ensuring air permeability in the blast furnace is formed, and the reduction agent ratio and coke ratio in blast furnace operation can be reduced.
  • FIG. 1 is a schematic cross-sectional view of a coarse-grained ore layer 12 in which mixed coke charged by the method for charging raw materials into a blast furnace according to the present embodiment and a fine-grained ore layer 14 in which mixed coke is mixed.
  • FIG. 2 is a graph showing the relationship between the mixing amount of mixed coke mixed with the coarse-grained ore of the first batch and the reduction rate.
  • the ore is divided into coarse-grained ore and fine-grained ore in order to maintain high reducibility while ensuring air permeability in the blast furnace, and mixed coke is mixed with each of the coarse-grained ore mixed with mixed coke. Fine-grained ore mixed with mixed coke.
  • the present inventors flow into the center side of the furnace, and the difference in specific gravity and the difference in particle size between the coke and the ore. It was confirmed that the coke mixed with the coarse-grained ore was separated and segregated toward the center of the furnace.
  • the coke mixed with the ore is described as mixed coke to distinguish it from the coke used for forming the coke layer in the blast furnace.
  • the particle size of the mixed coke is in the range of 5-40 mm.
  • the ore is a sinter produced in a sintering plant, and coarse-grained ore and fine-grained ore having an average particle size smaller than that of the coarse-grained ore have a size within the range of 4 to 10 mm. It is divided by sieving the sinter using an open sieve. As the sieve, various types such as a woven net, a punch metal, and a grizzly bar, which are generally used for sieving ore, may be used. Since a large amount of ore is used in the blast furnace, it is preferable to use a grizzly bar type sieve.
  • the sinter By dividing the sinter using a sieve with a mesh size in the range of 4 to 10 mm, the sinter can be divided into coarse-grained ore and fine-grained ore at an appropriate mass ratio, and the reaction of the coarse-grained ore. It is possible to suppress the decrease in sex. If a sieve having a mesh size smaller than 4 mm is used, the amount of fine-grained ore collected becomes extremely small and most of the fine-grained ore becomes coarse-grained ore, which makes it difficult to charge the ore by particle size classification, which is not preferable. It is not preferable to use a sieve having a mesh size larger than 10 mm because the average particle size of the coarse-grained ore increases and the reactivity of the ore decreases.
  • the sintered ore is sieved with a sieve having an opening of any size within the range of 4 to 10 mm, and the sintered ore sieved on the sieve is a coarse-grained ore, which is sieved under the sieve.
  • the sieved ore is a fine-grained ore.
  • the mass ratio of coarse-grained ore to fine-grained ore changes depending on the particle size distribution of the ore and the size of the opening to be divided, but the mass ratio of coarse-grained ore to fine-grained ore is in the range of 50:50 to 90:10. It is preferable to select a sieve having a wide opening.
  • the controllability of the ore particle size in the radial direction inside the furnace is improved. do. It is more preferable that the sinter is sieved using a sieve having a mesh size of 5 to 8 mm and divided into coarse-grained ore and fine-grained ore.
  • the particle size distribution of the sinter may fluctuate depending on the operating conditions of the sinter.
  • the coarse-grained ore and the fine-grained ore are sieved by keeping the mesh size of the sieve constant so that the mass ratio of the coarse-grained ore and the fine-grained ore is approximately 50:50. Then, it may be appropriately mixed and used according to the balance between the coarse-grained ore and the fine-grained ore used in the blast furnace. That is, if the coarse-grained ore used in the blast furnace is insufficient, a part of the fine-grained ore is mixed with the coarse-grained ore. May be mixed with.
  • the ore used for forming the ore layer mixed with mixed coke is divided into coarse-grained ore and fine-grained ore by the method described above. Then, mixed coke is mixed with each of the coarse-grained ore and the fine-grained ore to prepare a coarse-grained ore mixed with the mixed coke and a coarse-grained ore mixed with the mixed coke.
  • the mixing amount of the mixed coke to be mixed with the coarse-grained ore and the fine-grained ore may be 30 kg / t-pig or more and 100 kg / t-pig or less, and 40 kg / t-pig or more and 80 kg / t-pig or less. preferable.
  • the unit kg / t-pig is the mass (kg) of the mixed coke to be mixed with respect to the mass (t) of the hot metal produced by melting and reducing each of the coarse-grained ore or the fine-grained ore in which the mixed coke is mixed. ).
  • Mixed coke and coarse-grained ore are mixed, for example, by further depositing mixed coke on a conveyor on which coarse-grained ore is deposited.
  • the coarse-grained ore mixed with mixed coke is charged into the furnace top hopper by a conveyor and charged into the blast furnace via a charging chute.
  • mixed coke and fine-grained ore are mixed by further depositing mixed coke on a conveyor on which fine-grained ore is deposited, for example.
  • the fine-grained ore mixed with mixed coke is charged into the furnace top hopper by a conveyor and charged into the blast furnace via a charging chute.
  • FIG. 1 is a schematic cross-sectional view of a coarse-grained ore layer 12 in which mixed coke charged by the method for charging raw materials into a blast furnace according to the present embodiment and a fine-grained ore layer 14 in which mixed coke is mixed. ..
  • the horizontal axis of FIG. 1 is the dimensionless furnace opening radius, which is a value obtained by dividing the distance from the furnace center by the furnace opening radius.
  • the vertical axis is the relative height from the reference height.
  • the ore mixed with mixed coke is charged into the blast furnace in two batches, and the coarse-grained ore layer 12 in which the mixed coke is mixed is formed by the charging of the first batch. By charging the batches, a fine-grained ore layer 14 in which mixed coke is mixed is formed.
  • the charging chute is tilted from the furnace center side to the furnace wall side from the midpoint between the furnace center and the furnace wall in the radial direction of the blast furnace in the first batch (hereinafter, This tilt is referred to as "reverse tilt") to charge the coarse-grained ore mixed with the mixed coke, and the coarse-grained ore layer 12 is formed on the coke layer 10.
  • the deposition surface of the coke layer 10 is inclined so that the central side of the furnace, which has a small dimensionless furnace opening radius, is low and the coke layer 10 is high toward the wall side.
  • the coarse-grained ore in which the mixed coke is mixed when the coarse-grained ore in which the mixed coke is mixed is charged by tilting the charging chute in the reverse direction, the coarse-grained ore in which the mixed coke is mixed so as to be piled up from below with respect to the inclined sedimentary surface of the coke layer 10. Since the ore is deposited, the coarse-grained ore does not spread in the radial direction of the furnace opening. As a result, the coarse-grained ore mixed with the mixed coke is suppressed from flowing into the furnace center side, and the segregation of the mixed coke toward the furnace center side is suppressed. As a result, a coarse-grained ore layer mixed with mixed coke that maintains high reduction reactivity while ensuring air permeability in the blast furnace is formed, and the ratio of reducing agents in blast furnace operation is reduced.
  • the charging chute is tilted from the furnace wall side to the furnace center side from the midpoint between the furnace center and the furnace wall (hereinafter, this tilt is referred to as "forward tilt") to mix coke.
  • this tilt is referred to as "forward tilt" to mix coke.
  • the coarse-grained ore mixed with the above is charged, the coarse-grained ore is charged so as to flow from above the inclined surface on the furnace wall side to below the inclined surface on the furnace center side.
  • the coarse-grained ore flows into the furnace center side and spreads and deposits on the furnace center side.
  • the mixed coke mixed with the coarse-grained ore is separated due to the difference in specific gravity and particle size between the mixed coke and the ore, and the mixed coke is segregated toward the center of the furnace.
  • the mixed coke segregates toward the center of the furnace the amount of mixed coke effectively mixed with the ore is reduced, so that high reduction reactivity is not maintained and the ratio of reducing agent in blast furnace operation is high.
  • FIG. 2 is a graph showing the relationship between the mixing amount of mixed coke mixed in the coarse-grained ore of the first batch and the average reduction rate up to 1300 ° C.
  • the horizontal axis of FIG. 2 is the mixing amount of mixed coke (kg / t-pig), and the vertical axis is the average reduction rate (m Cincinnatil / min) up to 1300 ° C.
  • the average reduction rate is the average reduction rate obtained when 1550 g of ore is heated from 1000 ° C. to 1300 ° C. at 5 ° C./min under each coke mixing condition and reduced with CO gas, and is removed by reduction. It is a value showing the amount of oxygen in mol.
  • FIG. 2 shows the above relationship when the charging chute is tilted in the reverse direction to charge the coarse-grained ore mixed with mixed coke.
  • the dotted line in FIG. 2 shows the above relationship when the charging chute is tilted forward to charge the coarse-grained ore mixed with mixed coke.
  • the effect of improving the reduction rate with respect to the mixed coke amount is that the charging chute is tilted in the reverse direction to charge the coarse-grained ore rather than the charging chute is tilted forward to charge the coarse-grained ore. It was higher to enter. From this result, by tilting the charging chute in the reverse direction and charging the coarse-grained ore mixed with the mixed coke of the first batch, segregation of the mixed coke toward the center of the furnace is suppressed, which results in high reduction. It was confirmed that a coarse-grained ore layer mixed with mixed coke that maintains reactivity can be formed.
  • the fine-grained ore mixed with the mixed coke is charged into the blast furnace in the second batch, which is the final batch after the charging of the coarse-grained ore.
  • the fine-grained ore layer 14 is formed on the coarse-grained ore layer 12.
  • the coarse-grained ore layer 12 is inclined so as to be gently lowered from the midpoint between the center of the furnace and the furnace wall toward the furnace wall side. Therefore, it is preferable that the fine-grained ore mixed with the mixed coke is charged into the blast furnace by tilting the charging chute forward.
  • the fine-grained ore By charging the fine-grained ore in this way, the fine-grained ore is deposited so as to be piled up from below the inclined coarse-grained ore layer 12, so that the charged coarse-grained ore does not spread in the radial direction of the furnace opening. ..
  • the fine-grained ore mixed with the mixed coke is suppressed from flowing into the furnace wall side, and the segregation of the mixed coke toward the furnace wall side is suppressed.
  • a fine-grained ore layer mixed with mixed coke that maintains high reduction reactivity is formed, and the ratio of the reducing agent can be further reduced.
  • the fine-grained ore when the second batch of fine-grained ore is charged by tilting the charging chute in the reverse direction, the fine-grained ore is loaded so as to flow from above the inclined surface on the center side of the furnace to below the inclined surface on the furnace wall side. Be entered. Therefore, the fine-grained ore spreads and accumulates on the furnace wall side.
  • the mixed coke mixed with the fine-grained ore segregates toward the furnace wall side due to the difference in specific gravity and particle size between the coke and the ore.
  • the mixed coke segregates toward the furnace wall side, the amount of mixed coke effectively mixed with the ore is reduced.
  • the high reduction reactivity at the furnace wall is not maintained as compared with the case where the second batch of fine-grained ore is charged by tilting the charging chute forward, and the ratio of the reducing agent in the blast furnace operation is relatively high. It gets higher.
  • the ore is divided into coarse-grained ore and fine-grained ore, and mixed coke is mixed with each.
  • the charging chute is tilted in the reverse direction to charge the coarse-grained ore mixed with the mixed coke into the blast furnace.
  • the ore is divided into coarse-grained ore and fine-grained ore, mixed coke is mixed with each, and the coarse-grained ore mixed with mixed coke is charged in the first batch, and the final batch is obtained.
  • An example of charging fine-grained ore mixed with mixed coke was shown in the second batch, but the present invention is not limited to this.
  • the mixture of ore and mixed coke may be divided into 3 or more batches. Even in this case, segregation of the mixed coke toward the center of the furnace is suppressed by charging all or part of the coarse-grained ore mixed with the mixed coke by reversely tilting the charging chute in at least the first batch. NS.
  • the ratio of the reducing agent in the blast furnace operation is reduced as compared with the case where the charging chute is tilted forward in the first batch and the coarse-grained ore mixed with the mixed coke is charged. Furthermore, by tilting the charging chute forward to charge the final batch with all or part of the fine-grained ore mixed with mixed coke, high reduction reactivity at the furnace wall is maintained, and reduction in blast furnace operation. The material ratio can be reduced.
  • the mixture of ore and mixed coke is divided into 3 or more batches and charged, in the ore batches other than the first batch and the final batch, even if the coarse-grained ore mixed with the mixed coke is charged, it is mixed. Fine-grained ore mixed with coke may be charged. In this batch, it is more preferable to charge coarse-grained ore mixed with mixed coke or fine-grained ore mixed with mixed coke by reverse tilting. By charging these raw materials in a reverse tilt, the flow of the mixed coke with a part of the mixed coke charged in the previous batch to the furnace center side is suppressed, so that the mixed coke segregates toward the furnace center side. Is suppressed.
  • the coarse-grained ore and fine-grained ore mixed with mixed coke were charged into the blast furnace by the method of charging the raw material into the blast furnace according to the present embodiment, and the blast furnace was operated, and the effect of reducing the reducing agent ratio and the coke ratio was confirmed.
  • the example described will be described.
  • a blast furnace equipped with a bellless charging device with a charging chute and having an internal volume of 5000 m 3 is first charged with coke to form a coke layer, and then the ore is loaded in the furnace using the bellless charging device. It entered to form an ore layer. This operation was repeated, and the coke layer and the ore layer were alternately formed in the furnace to operate the blast furnace.
  • Example 1 the ratio of the average grain size of the coarse-grained ore to the average grain size of the fine-grained ore, the tilting direction of the charging chute of the first batch, and the tilting direction of the charging chute of the second batch and the mixing of mixed coke.
  • the reducing agent ratio and coke ratio in blast furnace operation were measured with and without change and under the same other conditions.
  • the measurement conditions and measurement results of Comparative Examples 1 to 5 and Invention Examples 1 to 3 are shown in Table 1 below.
  • the mixing ratio of mixed coke is 60 kg / t-pig.
  • the sieves used to separate the coarse-grained ore and the fine-grained ore are sieves with a mesh size of 10 mm (average particle size ratio 1.85) and a mesh size of 14 mm (average particle size ratio 1.35).
  • the average particle size ratio is a value obtained by dividing the average particle size of the coarse-grained ore sieved by the above-mentioned sieve by the average particle size of the fine-grained ore.
  • the average particle size of the fine-grained ore sieved using a sieve having a mesh size of 10 mm was 8 mm, and the average particle size of the coarse-grained ore was 14.8 mm.
  • the mass ratio of this coarse-grained ore to the fine-grained ore was 66:34.
  • the average particle size of the fine-grained ore sieved using the opening of 14 mm was 12 mm, and the average particle size of the coarse-grained ore was 16.2 mm.
  • the mass ratio of this coarse-grained ore to the fine-grained ore was 58:42.
  • the average particle size of the mixed coke was 25 mm.
  • the average particle size of both ore and coke was determined by sieving using a sieve having a nominal opening of 1 mm or more specified in JISZ 8801-2019.
  • As the representative diameter of the sieved mass 0.5 mm under the sieve of 1 mm is used, and the average value of the main dimensions of each sieve and the sieve with the opening above it is used for the others, and the sieve is sieved with respect to the representative diameter.
  • the average particle size was obtained by weighted averaging the obtained mass.
  • “O1 tilting direction” in Table 1 indicates the tilting direction of the ore charging chute charged in the first batch.
  • the “O2 tilting direction” indicates the tilting direction of the ore charging chute charged in the second batch.
  • coarse-grained ore was charged in the first batch, and fine-grained ore was charged in the second batch.
  • "Forward” in the tilting direction indicates that the charging chute was tilted forward to charge the ore, and "reverse” indicates that the charging chute was tilted in the reverse direction to charge the ore.
  • Invention Example 1 the ore was divided into coarse-grained ore and fine-grained ore (particle size ratio 1.35), mixed coke was mixed with these, and the coarse-grained ore was charged in the first batch by reverse tilting.
  • Invention Example 1 has a higher gas utilization rate than Comparative Example 3 in which coarse-grained ore is charged in the first batch under the same conditions by forward tilting, the pressure loss of the packed bed is reduced, and the reducing agent ratio and the reducing agent ratio are reduced. The coke ratio has been reduced.
  • Invention Example 3 the ore is divided into coarse-grained ore and fine-grained ore (particle size ratio: 1.83), mixed coke is mixed with these, and the coarse-grained ore is charged in the first batch by reverse tilting. did.
  • Invention Example 3 has a higher gas utilization rate than Comparative Example 5 in which coarse-grained ore is charged in the first batch under the same conditions by forward tilting, the pressure loss of the packed bed is reduced, and the reducing agent ratio and the reducing agent ratio are reduced. The coke ratio has been reduced.
  • the coarse-grained ore of the first batch is loaded with the reverse tilt regardless of whether the tilting direction of the fine-grained ore of the second batch is forward tilting or reverse tilting. It can be seen that the reducing agent ratio and the coke ratio can be reduced as compared with the case where the coarse-grained ore of the first batch is charged in a forward tilting manner. Based on these results, the ore was divided into coarse-grained ore and fine-grained ore, mixed coke was mixed with each, and the coarse-grained ore mixed with mixed coke was charged in the first batch by reverse tilting to blast furnace. It was confirmed that the reducing agent ratio and coke ratio in operation can be reduced.
  • Comparative Examples 2 and 4 in which the ore was divided into a coarse-grained ore and a fine-grained ore, the coarse-grained ore was charged in the first batch, and the fine-grained ore was charged in the second batch, the ore was regarded as the coarse-grained ore.
  • the reducing material ratio and the coke ratio were reduced as compared with Comparative Example 1 in which the ore was charged without being divided into fine-grained ores.
  • Comparative Examples 2 and 4 since the mixed coke was not mixed, the reduction reactivity was inferior, and therefore, the reducing agent ratio and the coke ratio were increased as compared with Comparative Examples 3 and 5.
  • Table 2 shows an example in which the same blast furnace as in Example 1 was used, the ore was charged in 3 batches, and the operation was performed under the condition of a tapping ratio of 2.0.
  • the sieving of coarse-grained ore and fine-grained ore was also set under two conditions, that is, an average particle size ratio of 1.35 and 1.85, as in Example 1.
  • the measurement conditions and measurement results of Comparative Example 11 and Invention Examples 11 to 24 are shown in Table 2 below.
  • “O1 tilting direction” in Table 2 indicates the tilting direction of the ore charging chute charged in the first batch.
  • the “O2 tilting direction” indicates the tilting direction of the ore charging chute charged in the second batch.
  • the “O3 tilting direction” indicates the tilting direction of the ore charged in the third batch, which is the final batch.
  • “Forward” in the tilting direction indicates that the charging chute was tilted forward to charge the ore, and “reverse” indicates that the charging chute was tilted in the reverse direction to charge the ore.
  • Comparative Example 11 and Invention Examples 11 and 12 the ore was divided into coarse-grained ore and fine-grained ore (particle size ratio 1.35), and mixed coke was mixed therewith.
  • each batch of the first batch and the second batch was a coarse-grained ore
  • the third batch was a fine-grained ore, all of which were charged in a forward tilting manner.
  • coarse-grained ore was charged in the first batch by reverse tilting
  • coarse-grained ore was charged in the second batch by reverse tilting
  • fine-grained ore was charged in the third batch by forward tilting. I charged it.
  • Invention Example 12 coarse-grained ore was charged in the first batch by reverse tilting, fine-grained ore was charged in the second batch by forward tilting, and fine-grained ore was charged in the third batch by forward tilting.
  • the gas utilization rate was higher than that of Comparative Example 11, the pressure loss of the packed bed was reduced, and the reducing agent ratio and the coke ratio were reduced.
  • Invention Example 11 in which the second batch was charged in the reverse tilt was more preferable because the reducing agent ratio and the coke ratio were reduced as compared with Invention Example 12 in which the second batch was charged in the forward tilt.
  • the second batch is a fine-grained ore
  • the third batch is a coarse-grained ore
  • the tilting directions of the charging chutes of the second and third batches are reversed and ordered in four patterns.
  • the raw materials were charged.
  • the gas utilization rate was higher than that of Comparative Example 11, the pressure loss of the packed bed was reduced, and the reducing agent ratio and the coke ratio were reduced.
  • the second batch is a coarse-grained ore
  • the third batch is a fine-grained ore
  • the tilting directions of the charging chutes of the second and third batches are reversed and ordered in four patterns.
  • the raw materials were charged.
  • the gas utilization rate was higher than that of Comparative Example 11, the pressure loss of the packed bed was reduced, and the reducing agent ratio and the coke ratio were reduced.
  • Invention Examples 18 and 20 in which the third batch was charged in the forward tilt have a higher gas utilization rate and pressure loss in the packed bed than in Invention Examples 17 and 19 in which the third batch was charged in the reverse tilt. was reduced, confirming that it was more preferable.
  • the gas utilization rate was higher than that of Comparative Example 11, the pressure loss of the packed bed was reduced, and the reducing agent ratio and the coke ratio were reduced.
  • Invention Examples 22 and 24 in which the third batch was charged in the forward tilt have the same or higher gas utilization rate than Invention Examples 21 and 23 in which the third batch was charged in the reverse tilt, and the filling layer It was confirmed that the pressure loss was reduced, which was more preferable.

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Abstract

A method for charging raw material into a blast furnace is provided which, while ensuring air ventilation inside of the furnace, enables forming an ore layer comprising an admixed coke mixture in which high reduction reactivity is maintained.　This method for charging raw material into a blast furnace involves using a bell-less charging device with a charge chute, dividing a mixture of ore and a coke mixture into at least two batches, and charging into the blast furnace, wherein the ore is divided into coarse-grain ore, and a fine-grain ore that has an average diameter smaller than that of the coarse-grain ore; the coke mixture is mixed with the coarse-grain ore to obtain coarse-grain ore with admixed coke mixture, and the coke mixture is mixed with the fine-grain ore to form fine-grain ore with admixed coke mixture; and, for at least the first batch, the aforementioned charging chute is tilted from the furnace center towards the furnace wall beyond an intermediate point in the blast furnace radial direction between the furnace center and the furnace wall, charging all or part of the coarse-grain ore with admixed coke mixture.

Description

高炉への原料装入方法How to charge raw materials to the blast furnace
　本発明は、高炉への原料装入方法に関する。 The present invention relates to a method of charging raw materials into a blast furnace.
　高炉では、炉頂部から原料である鉱石とコークスを所定量ずつ交互に装入して、炉内に鉱石層とコークス層とを交互に積層させている。この一層分の鉱石、コークスをそれぞれ１チャージ分の鉱石、コークスという。高炉では、炉内の鉱石層、コークス層の炉半径方向での層厚比を制御することで炉内のガス流れを制御している。装入シュートを有するベルレス装入装置を有する高炉では、安定な高炉操業を実現し、還元材比を低減できる層厚比分布を形成させるために、原料を装入する間に装入シュートの傾動角を適宜変更している。更に、高炉内のガス流れを制御するために、各チャージの鉱石やコークスを複数回バッチに分けて装入することも行われている。 In the blast furnace, the ore and coke, which are the raw materials, are alternately charged from the top of the furnace in predetermined amounts, and the ore layer and the coke layer are alternately laminated in the furnace. This layer of ore and coke is called one charge of ore and coke, respectively. In a blast furnace, the gas flow in the furnace is controlled by controlling the layer thickness ratio of the ore layer and the coke layer in the furnace in the furnace radial direction. In a blast furnace having a bellless charging device with a charging chute, the charging chute is tilted during charging of raw materials in order to realize stable blast furnace operation and form a layer thickness ratio distribution that can reduce the reducing agent ratio. The corners are changed as appropriate. Further, in order to control the gas flow in the blast furnace, the ore and coke of each charge are charged in batches a plurality of times.
　近年、地球温暖化防止の観点からＣＯ２削減が求められている。鉄鋼業においてはＣＯ２排出量の約７０％が高炉によるものなので、高炉におけるＣＯ２排出量の削減が求められる。高炉におけるＣＯ２排出量の削減は、高炉で使用する還元材（コークス、微粉炭、天然ガスなど）の削減により可能である。ここで、還元材を削減する１つの手段として、鉱石層へのコークス混合技術が知られている。非特許文献１には、鉱石層に５０ｋｇ／ｔ－ｐｉｇの小塊コークスを混合することで高炉操業における還元材比を低減できることが開示されている。 In recent years, CO 2 reduction has been required from the viewpoint of preventing global warming. In the steel industry, about 70% of CO 2 emissions are from blast furnaces, so reduction of CO 2 emissions in blast furnaces is required. The reduction of CO 2 emissions in the blast furnace is possible by reducing the reducing agents (coke, pulverized coal, natural gas, etc.) used in the blast furnace. Here, as one means for reducing the reducing agent, a coke mixing technique for an ore layer is known. Non-Patent Document 1 discloses that the ratio of reducing agent in blast furnace operation can be reduced by mixing 50 kg / t-pi small coke in the ore layer.
　鉱石層へのコークス混合技術として、特許文献１には、鉱石層を２バッチに分けて装入する際の１バッチ目を鉱石とコークスの混合物とし、このうちの前半は装入シュートを炉壁側から炉中心側へ傾動させて装入する順傾動装入とし、後半は炉中心側から炉壁側へ傾動させて装入する逆傾動装入とする方法が開示されている。特許文献１によると、このように装入することでコークス混合率が制御され、これにより鉱石の還元性を改善できるとしている。特許文献２には、炉中心付近に装入される鉱石に小塊コークスを混合した上で、順傾動装入する方法が開示されている。 As a coke mixing technique for an ore layer, Patent Document 1 states that the first batch when the ore layer is divided into two batches is a mixture of ore and coke, and the first half of the mixture is a charging chute as a furnace wall. A method is disclosed in which a forward tilting charge is used in which the charge is tilted from the side to the center side of the furnace, and a reverse tilt charge is used in which the charge is tilted from the center side of the furnace to the furnace wall side in the latter half. According to Patent Document 1, the coke mixing ratio is controlled by charging in this way, and the reducing property of the ore can be improved by this. Patent Document 2 discloses a method in which small coke is mixed with ore charged in the vicinity of the center of the furnace and then charged in a forward tilted manner.
　一方、高炉の生産性は高炉へ送風できる風量に律されるので、高炉内の通気性確保も重要である。高炉内の通気性を確保する技術として、非特許文献２には、焼結鉱を分級し粗粒を中心側に、細粒を高炉周辺側に装入する方法が開示されている。 On the other hand, the productivity of the blast furnace is regulated by the amount of air that can be blown to the blast furnace, so it is important to ensure the air permeability inside the blast furnace. As a technique for ensuring air permeability in the blast furnace, Non-Patent Document 2 discloses a method of classifying the sinter and charging coarse particles on the center side and fine particles on the peripheral side of the blast furnace.
特許第６２６０２８８号公報Japanese Patent No. 6260288 特許第６１６７８２９号公報Japanese Patent No. 6167829
　粗粒鉱石を高炉中心側に装入することで高炉内の通気性は改善されると考えられるが、粗粒鉱石は比表面積が小さく炉内での反応性が劣るので、かえって高炉の還元材比を上昇させてしまう懸念がある。この粗粒鉱石の還元反応性を担保するために、コークス混合技術の適用が考えられる。しかしながら、特許文献１、２に開示された順傾動装入では、装入位置から炉中心側に流れ込むように鉱石とコークスの混合物が装入される。このため、鉱石に比べて比重の軽いコークスが分離し、炉中心側に偏析させてしまう懸念がある。炉中心側にコークスが偏析すると有効に鉱石と混合されるコークスの割合が少なくなるので還元反応性の改善効果が得られない、という課題があった。 It is thought that the air permeability in the blast furnace can be improved by charging the coarse-grained ore into the center side of the blast furnace. There is a concern that the ratio will increase. In order to ensure the reduction reactivity of this coarse-grained ore, the application of coke mixing technology can be considered. However, in the forward tilt charging disclosed in Patent Documents 1 and 2, a mixture of ore and coke is charged so as to flow from the charging position toward the center of the furnace. For this reason, there is a concern that coke, which has a lighter specific density than ore, will separate and segregate toward the center of the furnace. When coke segregates on the center side of the furnace, the proportion of coke that is effectively mixed with the ore decreases, so there is a problem that the effect of improving the reduction reactivity cannot be obtained.
　本発明は、このような従来技術の課題を鑑みてなされたものであり、その目的は、高炉内の通気性を確保しつつ高い還元反応性が維持される混合コークスが混合された粗粒鉱石層を形成できる、高炉への原料装入方法を提供することである。 The present invention has been made in view of such problems of the prior art, and an object of the present invention is a coarse-grained ore mixed with mixed coke that maintains high reduction reactivity while ensuring air permeability in a blast furnace. It is to provide a method of charging raw materials into a blast furnace capable of forming a layer.
　上記課題を解決するための手段は、以下の通りである。
（１）装入シュートを有するベルレス装入装置を用いて鉱石と混合コークスとの混合物を２バッチ以上に分割して高炉内に装入する高炉への原料装入方法であって、前記鉱石を粗粒鉱石と、前記粗粒鉱石よりも平均粒径が小さい細粒鉱石とに分け、前記粗粒鉱石に混合コークスを混合して混合コークスが混合された粗粒鉱石とし、前記細粒鉱石に混合コークスを混合して混合コークスが混合された細粒鉱石とし、少なくとも１バッチ目に高炉の半径方向における炉中心と炉壁との中間点よりも炉中心側から炉壁側へ前記装入シュートを傾動させて前記混合コークスが混合された粗粒鉱石の全部または一部を装入する、高炉への原料装入方法。
（２）最終バッチで前記高炉の半径方向における炉中心と炉壁との中間点よりも炉壁側から炉中心側へ前記装入シュートを傾動させて前記混合コークスが混合された細粒鉱石の全部または一部を装入する、（１）に記載の高炉への原料装入方法。 The means for solving the above problems are as follows.
(1) A method of charging raw materials into a blast furnace in which a mixture of ore and mixed coke is divided into two or more batches using a bellless charging device having a charging chute and charged into the blast furnace. It is divided into coarse-grained ore and fine-grained ore having an average particle size smaller than that of the coarse-grained ore, and mixed coke is mixed with the coarse-grained ore to obtain a coarse-grained ore in which mixed coke is mixed. The mixed coke is mixed to form a fine-grained ore in which the mixed coke is mixed, and the charging chute is made from the furnace center side to the furnace wall side of the midpoint between the furnace center and the furnace wall in the radial direction of the blast furnace in at least the first batch. A method for charging a raw material into a blast furnace, in which all or a part of the coarse-grained ore mixed with the mixed coke is charged by tilting.
(2) In the final batch, the charging chute is tilted from the furnace wall side to the furnace center side from the midpoint between the furnace center and the furnace wall in the radial direction of the blast furnace, and the mixed coke is mixed in the fine-grained ore. The method for charging raw materials into a blast furnace according to (1), wherein all or part of the material is charged.
　本発明に係る高炉への原料装入方法を実施することで、混合コークスが混合された粗粒鉱石が炉中心側に流れ込むことが抑制され、炉中心側にコークスが偏析することが抑制される。これにより、高炉内の通気性を確保しつつ高い還元反応性が維持される混合コークスが混合された粗粒鉱石層が形成され、高炉操業における還元材比およびコークス比の低減が実現できる。 By implementing the method for charging the raw material into the blast furnace according to the present invention, the coarse-grained ore mixed with the mixed coke is suppressed from flowing into the furnace center side, and the coke is suppressed from segregating toward the furnace center side. .. As a result, a coarse-grained ore layer mixed with mixed coke that maintains high reduction reactivity while ensuring air permeability in the blast furnace is formed, and the reduction agent ratio and coke ratio in blast furnace operation can be reduced.
図１は、本実施形態に係る高炉への原料装入方法で装入された混合コークスが混合された粗粒鉱石層１２および混合コークスが混合された細粒鉱石層１４の断面模式図である。FIG. 1 is a schematic cross-sectional view of a coarse-grained ore layer 12 in which mixed coke charged by the method for charging raw materials into a blast furnace according to the present embodiment and a fine-grained ore layer 14 in which mixed coke is mixed. .. 図２は、１バッチ目の粗粒鉱石に混合する混合コークスの混合量と還元速度との関係を示すグラフである。FIG. 2 is a graph showing the relationship between the mixing amount of mixed coke mixed with the coarse-grained ore of the first batch and the reduction rate.
　高炉内の通気性を確保しつつ高い還元性を維持させるために鉱石を粗粒鉱石と細粒鉱石とに分割し、それぞれに混合コークスを混合して混合コークスが混合された粗粒鉱石と、混合コークスが混合された細粒鉱石とする。本発明者らは、装入シュートを順傾動させて混合コークスが混合された粗粒鉱石を高炉内に装入すると、これらが炉中心側に流れ込み、コークスと鉱石との比重差および粒径差により、粗粒鉱石に混合されたコークスが分離し炉中心側に偏析することを確認した。この対策として、混合コークスが混合された粗粒鉱石を逆傾動させて高炉内に装入することで粗粒鉱石に混合された混合コークスの偏析が抑制され、高炉内の通気性を確保しつつ高い還元反応性が維持される混合コークスが混合された粗粒鉱石層を形成できることを見出して本発明を完成させた。以下、本発明の実施の形態を通じて本発明を説明する。 The ore is divided into coarse-grained ore and fine-grained ore in order to maintain high reducibility while ensuring air permeability in the blast furnace, and mixed coke is mixed with each of the coarse-grained ore mixed with mixed coke. Fine-grained ore mixed with mixed coke. When the coarse-grained ore mixed with mixed coke is charged into the blast furnace by tilting the charging chute forward, the present inventors flow into the center side of the furnace, and the difference in specific gravity and the difference in particle size between the coke and the ore. It was confirmed that the coke mixed with the coarse-grained ore was separated and segregated toward the center of the furnace. As a countermeasure, segregation of the mixed coke mixed with the coarse-grained ore is suppressed by reverse-tilting the coarse-grained ore mixed with the mixed coke and charging it into the blast furnace, while ensuring the air permeability in the blast furnace. The present invention was completed by finding that a coarse-grained ore layer mixed with mixed coke that maintains high reduction reactivity can be formed. Hereinafter, the present invention will be described through embodiments of the present invention.
　本実施形態の説明において、鉱石に混合するコークスを、高炉内のコークス層の形成に用いられるコークスと区別するために混合コークスと記載する。混合コークスの粒径は５～４０ｍｍの範囲内である。鉱石は、焼結工場で製造された焼結鉱であり、粗粒鉱石および当該粗粒鉱石よりも平均粒径が小さい細粒鉱石は、４～１０ｍｍの範囲内のいずれかの大きさの目開きの篩を用いて当該焼結鉱を篩分けすることで分割される。篩には、一般に鉱石の篩分けに使用される織網やパンチメタル、グリズリーバー等種々の型式のものを用いてよい。高炉では多量の鉱石が使用されるので、グリズリーバータイプの篩を用いることが好ましい。 In the description of this embodiment, the coke mixed with the ore is described as mixed coke to distinguish it from the coke used for forming the coke layer in the blast furnace. The particle size of the mixed coke is in the range of 5-40 mm. The ore is a sinter produced in a sintering plant, and coarse-grained ore and fine-grained ore having an average particle size smaller than that of the coarse-grained ore have a size within the range of 4 to 10 mm. It is divided by sieving the sinter using an open sieve. As the sieve, various types such as a woven net, a punch metal, and a grizzly bar, which are generally used for sieving ore, may be used. Since a large amount of ore is used in the blast furnace, it is preferable to use a grizzly bar type sieve.
　４～１０ｍｍの範囲内の目開きの篩を用いて焼結鉱を分割することで、焼結鉱を適切な質量割合で粗粒鉱石と細粒鉱石とに分割できるとともに、粗粒鉱石の反応性低下を抑制できる。４ｍｍより小さい目開きの篩を用いると、細粒鉱石の採取量が極端に少なくなって大半が粗粒鉱石になってしまい、鉱石の粒度分級による装入が困難になるので好ましくない。１０ｍｍより大きい目開きの篩を用いると、粗粒鉱石の平均粒径が大きくなって鉱石の反応性が低下するので好ましくない。 By dividing the sinter using a sieve with a mesh size in the range of 4 to 10 mm, the sinter can be divided into coarse-grained ore and fine-grained ore at an appropriate mass ratio, and the reaction of the coarse-grained ore. It is possible to suppress the decrease in sex. If a sieve having a mesh size smaller than 4 mm is used, the amount of fine-grained ore collected becomes extremely small and most of the fine-grained ore becomes coarse-grained ore, which makes it difficult to charge the ore by particle size classification, which is not preferable. It is not preferable to use a sieve having a mesh size larger than 10 mm because the average particle size of the coarse-grained ore increases and the reactivity of the ore decreases.
　すなわち、焼結鉱を４～１０ｍｍの範囲内のいずれかの大きさの目開きの篩で篩分け、篩上に篩分けられた焼結鉱が粗粒鉱石であり、篩下に篩分けられた焼結鉱が細粒鉱石である。鉱石の粒度分布および分割する目開きの大きさにより粗粒鉱石と細粒鉱石の質量比が変わるが、粗粒鉱石と細粒鉱石との質量比率が５０：５０～９０：１０の範囲内となる目開きの篩を選定することが好ましい。このように鉱石を所定の粒径で粗粒鉱石、細粒鉱石として分割し、それぞれを別のバッチで高炉内へ装入することで、炉内半径方向での鉱石粒径の制御性が向上する。５～８ｍｍの目開きの篩を用いて焼結鉱を篩分けして粗粒鉱石および細粒鉱石に分割することがより好ましい。 That is, the sintered ore is sieved with a sieve having an opening of any size within the range of 4 to 10 mm, and the sintered ore sieved on the sieve is a coarse-grained ore, which is sieved under the sieve. The sieved ore is a fine-grained ore. The mass ratio of coarse-grained ore to fine-grained ore changes depending on the particle size distribution of the ore and the size of the opening to be divided, but the mass ratio of coarse-grained ore to fine-grained ore is in the range of 50:50 to 90:10. It is preferable to select a sieve having a wide opening. By dividing the ore into coarse-grained ore and fine-grained ore with a predetermined particle size and charging each into the blast furnace in a separate batch, the controllability of the ore particle size in the radial direction inside the furnace is improved. do. It is more preferable that the sinter is sieved using a sieve having a mesh size of 5 to 8 mm and divided into coarse-grained ore and fine-grained ore.
　焼結鉱の粒度分布は焼結機の操業条件により変動することがある。このような場合には、たとえば、粗粒鉱石と細粒鉱石の質量比率が概ね５０：５０となるように篩の目開きを一定にして粗粒鉱石と細粒鉱石を篩分けしておく。そして、高炉で使用する粗粒鉱石と細粒鉱石のバランスに合わせて、適宜混合して使用してもよい。すなわち、高炉で使用する粗粒鉱石が足りない場合は細粒鉱石の一部を粗粒鉱石へ混合し、高炉で使用する細粒鉱石が足りない場合は粗粒鉱石の一部を細粒鉱石へ混合してもよい。 The particle size distribution of the sinter may fluctuate depending on the operating conditions of the sinter. In such a case, for example, the coarse-grained ore and the fine-grained ore are sieved by keeping the mesh size of the sieve constant so that the mass ratio of the coarse-grained ore and the fine-grained ore is approximately 50:50. Then, it may be appropriately mixed and used according to the balance between the coarse-grained ore and the fine-grained ore used in the blast furnace. That is, if the coarse-grained ore used in the blast furnace is insufficient, a part of the fine-grained ore is mixed with the coarse-grained ore. May be mixed with.
　本実施形態に係る高炉への原料装入方法では、混合コークスが混合された鉱石層の形成に用いられる鉱石を上述した方法で粗粒鉱石と細粒鉱石とに分割する。そして、粗粒鉱石および細粒鉱石のそれぞれに混合コークスを混合して、混合コークスが混合された粗粒鉱石および混合コークスが混合された粗粒鉱石を調製する。粗粒鉱石および細粒鉱石に混合する混合コークスの混合量は、３０ｋｇ／ｔ－ｐiｇ以上１００ｋｇ／ｔ－ｐiｇ以下であればよく、４０ｋｇ／ｔ－ｐiｇ以上８０ｋｇ／ｔ－ｐiｇ以下であることが好ましい。単位ｋｇ／ｔ－ｐiｇは、混合コークスを混合する粗粒鉱石あるいは細粒鉱石のそれぞれの鉱石が溶融、還元して製造される溶銑の質量（ｔ）に対する、混合される混合コークスの質量（ｋｇ）を表す。 In the method of charging raw materials into the blast furnace according to the present embodiment, the ore used for forming the ore layer mixed with mixed coke is divided into coarse-grained ore and fine-grained ore by the method described above. Then, mixed coke is mixed with each of the coarse-grained ore and the fine-grained ore to prepare a coarse-grained ore mixed with the mixed coke and a coarse-grained ore mixed with the mixed coke. The mixing amount of the mixed coke to be mixed with the coarse-grained ore and the fine-grained ore may be 30 kg / t-pig or more and 100 kg / t-pig or less, and 40 kg / t-pig or more and 80 kg / t-pig or less. preferable. The unit kg / t-pig is the mass (kg) of the mixed coke to be mixed with respect to the mass (t) of the hot metal produced by melting and reducing each of the coarse-grained ore or the fine-grained ore in which the mixed coke is mixed. ).
　混合コークスと粗粒鉱石は、例えば、粗粒鉱石が堆積したコンベア上に混合コークスをさらに堆積させることで混合される。混合コークスが混合された粗粒鉱石は、コンベアによって炉頂ホッパーに装入され、装入シュートを介して高炉内に装入される。 Mixed coke and coarse-grained ore are mixed, for example, by further depositing mixed coke on a conveyor on which coarse-grained ore is deposited. The coarse-grained ore mixed with mixed coke is charged into the furnace top hopper by a conveyor and charged into the blast furnace via a charging chute.
　同様に混合コークスと細粒鉱石は、例えば、細粒鉱石が堆積したコンベア上に混合コークスをさらに堆積させることで混合される。混合コークスが混合された細粒鉱石は、コンベアによって炉頂ホッパーに装入され、装入シュートを介して高炉内に装入される。 Similarly, mixed coke and fine-grained ore are mixed by further depositing mixed coke on a conveyor on which fine-grained ore is deposited, for example. The fine-grained ore mixed with mixed coke is charged into the furnace top hopper by a conveyor and charged into the blast furnace via a charging chute.
　図１は、本実施形態に係る高炉への原料装入方法で装入された混合コークスが混合された粗粒鉱石層１２および混合コークスが混合された細粒鉱石層１４の断面模式図である。図１の横軸は無次元炉口半径であり、炉中心からの距離を炉口半径で除した値である。縦軸は基準高さからの相対高さである。図１に示した例では、混合コークスが混合された鉱石は２バッチに分けて高炉に装入され、１バッチ目の装入により混合コークスが混合された粗粒鉱石層１２が形成され、２バッチ目の装入により混合コークスが混合された細粒鉱石層１４が形成される。 FIG. 1 is a schematic cross-sectional view of a coarse-grained ore layer 12 in which mixed coke charged by the method for charging raw materials into a blast furnace according to the present embodiment and a fine-grained ore layer 14 in which mixed coke is mixed. .. The horizontal axis of FIG. 1 is the dimensionless furnace opening radius, which is a value obtained by dividing the distance from the furnace center by the furnace opening radius. The vertical axis is the relative height from the reference height. In the example shown in FIG. 1, the ore mixed with mixed coke is charged into the blast furnace in two batches, and the coarse-grained ore layer 12 in which the mixed coke is mixed is formed by the charging of the first batch. By charging the batches, a fine-grained ore layer 14 in which mixed coke is mixed is formed.
　本実施形態に係る高炉への原料装入方法では、１バッチ目に装入シュートを高炉の半径方向における炉中心と炉壁との中間点よりも炉中心側から炉壁側へ傾動（以後、この傾動を「逆傾動」と記載する。）させて混合コークスが混合された粗粒鉱石を装入し、粗粒鉱石層１２をコークス層１０の上に形成させる。図１に示すように、コークス層１０の堆積面は、無次元炉口半径が小さい炉中心側が低く、炉壁側に向けて高くなるように傾斜している。このため、装入シュートを逆傾動させて混合コークスが混合された粗粒鉱石を装入すると、コークス層１０の傾斜した堆積面に対して下方から積み上がるように混合コークスが混合された粗粒鉱石が堆積するので、粗粒鉱石が炉口半径方向に広がらない。この結果、混合コークスが混合された粗粒鉱石が炉中心側に流れ込むことが抑制され、混合コークスの炉中心側への偏析が抑制される。これにより、高炉内の通気性を確保しつつ高い還元反応性が維持される混合コークスが混合された粗粒鉱石層が形成され、高炉操業における還元材比が低減する。 In the method of charging raw materials into the blast furnace according to the present embodiment, the charging chute is tilted from the furnace center side to the furnace wall side from the midpoint between the furnace center and the furnace wall in the radial direction of the blast furnace in the first batch (hereinafter, This tilt is referred to as "reverse tilt") to charge the coarse-grained ore mixed with the mixed coke, and the coarse-grained ore layer 12 is formed on the coke layer 10. As shown in FIG. 1, the deposition surface of the coke layer 10 is inclined so that the central side of the furnace, which has a small dimensionless furnace opening radius, is low and the coke layer 10 is high toward the wall side. Therefore, when the coarse-grained ore in which the mixed coke is mixed is charged by tilting the charging chute in the reverse direction, the coarse-grained ore in which the mixed coke is mixed so as to be piled up from below with respect to the inclined sedimentary surface of the coke layer 10. Since the ore is deposited, the coarse-grained ore does not spread in the radial direction of the furnace opening. As a result, the coarse-grained ore mixed with the mixed coke is suppressed from flowing into the furnace center side, and the segregation of the mixed coke toward the furnace center side is suppressed. As a result, a coarse-grained ore layer mixed with mixed coke that maintains high reduction reactivity while ensuring air permeability in the blast furnace is formed, and the ratio of reducing agents in blast furnace operation is reduced.
　一方、１バッチ目に、装入シュートを炉中心と炉壁との中間点よりも炉壁側から炉中心側へ傾動（以後、この傾動を「順傾動」と記載する。）させて混合コークスが混合された粗粒鉱石を装入すると、粗粒鉱石は炉壁側の傾斜面の上方から炉中心側の傾斜面の下方へ流れるように装入される。このように装入されると、粗粒鉱石は炉中心側に流れ込み、炉中心側に広がって堆積する。粗粒鉱石が炉中心側に広がると、混合コークスと鉱石との比重差および粒径差により粗粒鉱石に混合された混合コークスが分離し混合コークスが炉中心側に偏析する。混合コークスが炉中心側に偏析すると、鉱石に有効に混合される混合コークスの量が少なくなるので、高い還元反応性が維持されず高炉操業における還元材比が高くなる。 On the other hand, in the first batch, the charging chute is tilted from the furnace wall side to the furnace center side from the midpoint between the furnace center and the furnace wall (hereinafter, this tilt is referred to as "forward tilt") to mix coke. When the coarse-grained ore mixed with the above is charged, the coarse-grained ore is charged so as to flow from above the inclined surface on the furnace wall side to below the inclined surface on the furnace center side. When charged in this way, the coarse-grained ore flows into the furnace center side and spreads and deposits on the furnace center side. When the coarse-grained ore spreads toward the center of the furnace, the mixed coke mixed with the coarse-grained ore is separated due to the difference in specific gravity and particle size between the mixed coke and the ore, and the mixed coke is segregated toward the center of the furnace. When the mixed coke segregates toward the center of the furnace, the amount of mixed coke effectively mixed with the ore is reduced, so that high reduction reactivity is not maintained and the ratio of reducing agent in blast furnace operation is high.
　図２は、１バッチ目の粗粒鉱石に混合する混合コークスの混合量と１３００℃までの平均還元速度との関係を示すグラフである。図２の横軸は混合コークスの混合量（ｋｇ／ｔ－ｐｉｇ）であり、縦軸は１３００℃までの平均還元速度（ｍоｌ／ｍｉｎ）である。平均還元速度は、１５５０ｇの鉱石を各コークス混合条件において１０００℃から１３００℃まで５℃／ｍｉｎで昇温させ、ＣＯガスにて還元させた際に得られる平均還元速度であり、還元により除去される酸素量をｍｏｌ数で示した値である。図２の実線は、装入シュートを逆傾動させて混合コークスが混合された粗粒鉱石を装入した場合の上記関係を示す。図２の点線は、装入シュートを順傾動させて混合コークスが混合された粗粒鉱石を装入した場合の上記関係を示す。 FIG. 2 is a graph showing the relationship between the mixing amount of mixed coke mixed in the coarse-grained ore of the first batch and the average reduction rate up to 1300 ° C. The horizontal axis of FIG. 2 is the mixing amount of mixed coke (kg / t-pig), and the vertical axis is the average reduction rate (mоl / min) up to 1300 ° C. The average reduction rate is the average reduction rate obtained when 1550 g of ore is heated from 1000 ° C. to 1300 ° C. at 5 ° C./min under each coke mixing condition and reduced with CO gas, and is removed by reduction. It is a value showing the amount of oxygen in mol. The solid line in FIG. 2 shows the above relationship when the charging chute is tilted in the reverse direction to charge the coarse-grained ore mixed with mixed coke. The dotted line in FIG. 2 shows the above relationship when the charging chute is tilted forward to charge the coarse-grained ore mixed with mixed coke.
　図２に示すように、混合コークス混合量に対する還元速度の向上効果は、装入シュートを順傾動させて粗粒鉱石を装入するよりも、装入シュートを逆傾動させて粗粒鉱石を装入する方が高くなった。この結果から、装入シュートを逆傾動させて１バッチ目の混合コークスが混合された粗粒鉱石を装入することで、混合コークスの炉中心側への偏析が抑制され、これにより、高い還元反応性が維持される混合コークスが混合された粗粒鉱石層が形成できることが確認された。 As shown in FIG. 2, the effect of improving the reduction rate with respect to the mixed coke amount is that the charging chute is tilted in the reverse direction to charge the coarse-grained ore rather than the charging chute is tilted forward to charge the coarse-grained ore. It was higher to enter. From this result, by tilting the charging chute in the reverse direction and charging the coarse-grained ore mixed with the mixed coke of the first batch, segregation of the mixed coke toward the center of the furnace is suppressed, which results in high reduction. It was confirmed that a coarse-grained ore layer mixed with mixed coke that maintains reactivity can be formed.
　再び、図１を参照する。混合コークスが混合された細粒鉱石は、粗粒鉱石の装入後の最終バッチとなる２バッチ目に高炉内に装入される。これにより、粗粒鉱石層１２の上に細粒鉱石層１４が形成される。図１に示すように、粗粒鉱石層１２は、炉中心と炉壁の中間点から炉壁側に向けてなだらかに低くなるように傾斜している。このため、混合コークスが混合された細粒鉱石は、装入シュートを順傾動させて高炉内に装入されることが好ましい。このように細粒鉱石を装入することで、傾斜した粗粒鉱石層１２の下方から積み上がるように細粒鉱石が堆積するので、装入された粗粒鉱石が炉口半径方向に広がらない。これにより、混合コークスが混合された細粒鉱石が炉壁側に流れ込むことが抑制され、混合コークスの炉壁側への偏析が抑制される。この結果、高い還元反応性が維持される混合コークスが混合された細粒鉱石層が形成され、さらなる還元材比の低減が実現できる。 Refer to FIG. 1 again. The fine-grained ore mixed with the mixed coke is charged into the blast furnace in the second batch, which is the final batch after the charging of the coarse-grained ore. As a result, the fine-grained ore layer 14 is formed on the coarse-grained ore layer 12. As shown in FIG. 1, the coarse-grained ore layer 12 is inclined so as to be gently lowered from the midpoint between the center of the furnace and the furnace wall toward the furnace wall side. Therefore, it is preferable that the fine-grained ore mixed with the mixed coke is charged into the blast furnace by tilting the charging chute forward. By charging the fine-grained ore in this way, the fine-grained ore is deposited so as to be piled up from below the inclined coarse-grained ore layer 12, so that the charged coarse-grained ore does not spread in the radial direction of the furnace opening. .. As a result, the fine-grained ore mixed with the mixed coke is suppressed from flowing into the furnace wall side, and the segregation of the mixed coke toward the furnace wall side is suppressed. As a result, a fine-grained ore layer mixed with mixed coke that maintains high reduction reactivity is formed, and the ratio of the reducing agent can be further reduced.
　一方、２バッチ目の細粒鉱石が装入シュートを逆傾動させて装入されると、細粒鉱石は炉中心側の傾斜面の上方から炉壁側の傾斜面の下方へ流れるように装入される。このため、細粒鉱石は炉壁側に広がって堆積する。細粒鉱石が炉壁側に広がると、コークスと鉱石との比重差および粒径差により細粒鉱石に混合された混合コークスが炉壁側に偏析する。混合コークスが炉壁側に偏析すると、鉱石に有効に混合される混合コークスの量が少なくなる。この結果、２バッチ目の細粒鉱石が装入シュートを順傾動させて装入される場合と比較して炉壁部での高い還元反応性が維持されず高炉操業における還元材比が比較的高くなる。 On the other hand, when the second batch of fine-grained ore is charged by tilting the charging chute in the reverse direction, the fine-grained ore is loaded so as to flow from above the inclined surface on the center side of the furnace to below the inclined surface on the furnace wall side. Be entered. Therefore, the fine-grained ore spreads and accumulates on the furnace wall side. When the fine-grained ore spreads toward the furnace wall side, the mixed coke mixed with the fine-grained ore segregates toward the furnace wall side due to the difference in specific gravity and particle size between the coke and the ore. When the mixed coke segregates toward the furnace wall side, the amount of mixed coke effectively mixed with the ore is reduced. As a result, the high reduction reactivity at the furnace wall is not maintained as compared with the case where the second batch of fine-grained ore is charged by tilting the charging chute forward, and the ratio of the reducing agent in the blast furnace operation is relatively high. It gets higher.
　このように、本実施形態に係る高炉への原料装入方法では、鉱石を粗粒鉱石と細粒鉱石とに分け、それぞれに混合コークスを混合する。そして、１バッチ目に装入シュートを逆傾動させて混合コークスが混合された粗粒鉱石を高炉内に装入する。これにより、粗粒鉱石に混合された混合コークスが炉中心側に偏析することが抑制される。この結果、高炉内の通気性を確保しつつ高い還元反応性が維持される混合コークスが混合された粗粒鉱石層が形成され、高炉操業における還元材比の低減が実現できる。 As described above, in the method of charging the raw material into the blast furnace according to the present embodiment, the ore is divided into coarse-grained ore and fine-grained ore, and mixed coke is mixed with each. Then, in the first batch, the charging chute is tilted in the reverse direction to charge the coarse-grained ore mixed with the mixed coke into the blast furnace. As a result, it is possible to prevent the mixed coke mixed with the coarse-grained ore from segregating toward the center of the furnace. As a result, a coarse-grained ore layer mixed with mixed coke that maintains high reduction reactivity while ensuring air permeability in the blast furnace is formed, and the ratio of reducing agents in blast furnace operation can be reduced.
　本実施形態では、鉱石を粗粒鉱石と細粒鉱石とに分割し、それぞれに混合コークスを混合して、１バッチ目に混合コークスが混合された粗粒鉱石を装入し、最終バッチとなる２バッチ目に混合コークスが混合された細粒鉱石を装入する例を示したが、これに限らない。例えば、鉱石と混合コークスとの混合物を３バッチ以上に分割してもよい。この場合においても、少なくとも１バッチ目に装入シュートを逆傾動させて混合コークスが混合された粗粒鉱石の全部または一部を装入することで炉中心側への混合コークスの偏析が抑制される。このため、１バッチ目に装入シュートを順傾動させて混合コークスが混合された粗粒鉱石を装入した場合よりも高炉操業における還元材比は低減する。さらに、最終バッチに装入シュートを順傾動させて混合コークスが混合された細粒鉱石の全部または一部を装入することで炉壁部での高い還元反応性が維持され、高炉操業における還元材比の低減が実現できる。 In the present embodiment, the ore is divided into coarse-grained ore and fine-grained ore, mixed coke is mixed with each, and the coarse-grained ore mixed with mixed coke is charged in the first batch, and the final batch is obtained. An example of charging fine-grained ore mixed with mixed coke was shown in the second batch, but the present invention is not limited to this. For example, the mixture of ore and mixed coke may be divided into 3 or more batches. Even in this case, segregation of the mixed coke toward the center of the furnace is suppressed by charging all or part of the coarse-grained ore mixed with the mixed coke by reversely tilting the charging chute in at least the first batch. NS. Therefore, the ratio of the reducing agent in the blast furnace operation is reduced as compared with the case where the charging chute is tilted forward in the first batch and the coarse-grained ore mixed with the mixed coke is charged. Furthermore, by tilting the charging chute forward to charge the final batch with all or part of the fine-grained ore mixed with mixed coke, high reduction reactivity at the furnace wall is maintained, and reduction in blast furnace operation. The material ratio can be reduced.
　鉱石と混合コークスとの混合物を３バッチ以上に分割して装入する場合に、１バッチ目と最終バッチ以外の鉱石バッチでは、混合コークスが混合された粗粒鉱石を装入しても、混合コークスが混合された細粒鉱石を装入してもよい。このバッチでは、混合コークスが混合された粗粒鉱石または混合コークスが混合された細粒鉱石を逆傾動で装入することがより好ましい。これら原料を逆傾動で装入することで、その前のバッチで装入された混合コークスの一部を伴って炉中心側へ流れ込むことが抑制され、これにより、混合コークスが炉中心側に偏析することが抑制される。 When the mixture of ore and mixed coke is divided into 3 or more batches and charged, in the ore batches other than the first batch and the final batch, even if the coarse-grained ore mixed with the mixed coke is charged, it is mixed. Fine-grained ore mixed with coke may be charged. In this batch, it is more preferable to charge coarse-grained ore mixed with mixed coke or fine-grained ore mixed with mixed coke by reverse tilting. By charging these raw materials in a reverse tilt, the flow of the mixed coke with a part of the mixed coke charged in the previous batch to the furnace center side is suppressed, so that the mixed coke segregates toward the furnace center side. Is suppressed.
　本実施形態に係る高炉への原料装入方法で混合コークスが混合された粗粒鉱石および細粒鉱石を高炉に装入して高炉操業を実施し、還元材比およびコークス比の低減効果を確認した実施例を説明する。装入シュートを有するベルレス装入装置を備え、内容積が５０００ｍ３である高炉に、まずコークスを装入してコークス層を形成させた後、ベルレス装入装置を用いて炉内に鉱石を装入して鉱石層を形成させた。この操作を繰り返し実施し、炉内にコークス層と鉱石層とを交互に形成させて高炉操業を実施した。 The coarse-grained ore and fine-grained ore mixed with mixed coke were charged into the blast furnace by the method of charging the raw material into the blast furnace according to the present embodiment, and the blast furnace was operated, and the effect of reducing the reducing agent ratio and the coke ratio was confirmed. The example described will be described. A blast furnace equipped with a bellless charging device with a charging chute and having an internal volume of 5000 m 3 is first charged with coke to form a coke layer, and then the ore is loaded in the furnace using the bellless charging device. It entered to form an ore layer. This operation was repeated, and the coke layer and the ore layer were alternately formed in the furnace to operate the blast furnace.
　実施例１では、細粒鉱石の平均粒径に対する粗粒鉱石の平均粒径の比率、１バッチ目の装入シュートの傾動方向、２バッチ目の装入シュートの傾動方向および混合コークスの混合の有無を変え、他の条件は同じにして高炉操業における還元材比およびコークス比を測定した。比較例１～５および発明例１～３の測定条件および測定結果を下記表１に示す。混合コークスの混合率は６０ｋｇ／ｔ－ｐｉｇである。 In Example 1, the ratio of the average grain size of the coarse-grained ore to the average grain size of the fine-grained ore, the tilting direction of the charging chute of the first batch, and the tilting direction of the charging chute of the second batch and the mixing of mixed coke. The reducing agent ratio and coke ratio in blast furnace operation were measured with and without change and under the same other conditions. The measurement conditions and measurement results of Comparative Examples 1 to 5 and Invention Examples 1 to 3 are shown in Table 1 below. The mixing ratio of mixed coke is 60 kg / t-pig.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  
　粗粒鉱石と細粒鉱石とに分離するのに用いた篩は、目開き１０ｍｍ（平均粒径比１．８５）および目開き１４ｍｍ（平均粒径比１．３５）の篩である。平均粒径比とは、上記篩で篩分けられた粗粒鉱石の平均粒径を細粒鉱石の平均粒径で除した値である。 The sieves used to separate the coarse-grained ore and the fine-grained ore are sieves with a mesh size of 10 mm (average particle size ratio 1.85) and a mesh size of 14 mm (average particle size ratio 1.35). The average particle size ratio is a value obtained by dividing the average particle size of the coarse-grained ore sieved by the above-mentioned sieve by the average particle size of the fine-grained ore.
　目開き１０ｍｍの篩を用いて篩分けられた細粒鉱石の平均粒径は８ｍｍであり、粗粒鉱石の平均粒径は１４．８ｍｍであった。この粗粒鉱石と細粒鉱石との質量比は６６：３４であった。 The average particle size of the fine-grained ore sieved using a sieve having a mesh size of 10 mm was 8 mm, and the average particle size of the coarse-grained ore was 14.8 mm. The mass ratio of this coarse-grained ore to the fine-grained ore was 66:34.
　目開き１４ｍｍを用いて篩分けられた細粒鉱石の平均粒径は１２ｍｍであり、粗粒鉱石の平均粒径は１６．２ｍｍであった。この粗粒鉱石と細粒鉱石との質量比は５８：４２であった。混合コークスの平均粒径は２５ｍｍであった。 The average particle size of the fine-grained ore sieved using the opening of 14 mm was 12 mm, and the average particle size of the coarse-grained ore was 16.2 mm. The mass ratio of this coarse-grained ore to the fine-grained ore was 58:42. The average particle size of the mixed coke was 25 mm.
　平均粒径は、鉱石、コークス共に、ＪＩＳＺ　８８０１－２０１９に規定される公称目開き１ｍｍ以上の篩を用いて篩分けて求めた。篩分けられた質量の代表径として、１ｍｍの篩下は０．５ｍｍ、その他は各篩とその一つ上の目開きの篩の主寸法の平均値を使用し、代表径に対して篩分けられた質量を加重平均して平均粒径を求めた。 The average particle size of both ore and coke was determined by sieving using a sieve having a nominal opening of 1 mm or more specified in JISZ 8801-2019. As the representative diameter of the sieved mass, 0.5 mm under the sieve of 1 mm is used, and the average value of the main dimensions of each sieve and the sieve with the opening above it is used for the others, and the sieve is sieved with respect to the representative diameter. The average particle size was obtained by weighted averaging the obtained mass.
　表１における「Ｏ１傾動方向」は、１バッチ目に装入する鉱石の装入シュートの傾動方向を示す。「Ｏ２傾動方向」は、２バッチ目に装入する鉱石の装入シュートの傾動方向を示す。比較例２～５、発明例１～３においては、１バッチ目に粗粒鉱石を装入し、２バッチ目に細粒鉱石を装入した。傾動方向における「順」は、装入シュートを順傾動させて鉱石を装入したことを示し、「逆」は、装入シュートを逆傾動させて鉱石を装入したことを示す。 "O1 tilting direction" in Table 1 indicates the tilting direction of the ore charging chute charged in the first batch. The “O2 tilting direction” indicates the tilting direction of the ore charging chute charged in the second batch. In Comparative Examples 2 to 5 and Invention Examples 1 to 3, coarse-grained ore was charged in the first batch, and fine-grained ore was charged in the second batch. "Forward" in the tilting direction indicates that the charging chute was tilted forward to charge the ore, and "reverse" indicates that the charging chute was tilted in the reverse direction to charge the ore.
　発明例１では、鉱石を粗粒鉱石と細粒鉱石とに分割（粒径比１．３５）し、これらに混合コークスを混合して１バッチ目に粗粒鉱石を逆傾動で装入した。この結果、発明例１は、同じ条件で１バッチ目に粗粒鉱石を順傾動で装入した比較例３よりもガス利用率が高くなり、充填層の圧力損失が減少し、還元材比およびコークス比が低減した。同様に、発明例３では、鉱石を粗粒鉱石と細粒鉱石に分割（粒径比１．８３）し、これらに混合コークスを混合して１バッチ目に粗粒鉱石を逆傾動で装入した。この結果、発明例３は、同じ条件で１バッチ目に粗粒鉱石を順傾動で装入した比較例５よりもガス利用率が高くなり、充填層の圧力損失が減少し、還元材比およびコークス比が低減した。 In Invention Example 1, the ore was divided into coarse-grained ore and fine-grained ore (particle size ratio 1.35), mixed coke was mixed with these, and the coarse-grained ore was charged in the first batch by reverse tilting. As a result, Invention Example 1 has a higher gas utilization rate than Comparative Example 3 in which coarse-grained ore is charged in the first batch under the same conditions by forward tilting, the pressure loss of the packed bed is reduced, and the reducing agent ratio and the reducing agent ratio are reduced. The coke ratio has been reduced. Similarly, in Invention Example 3, the ore is divided into coarse-grained ore and fine-grained ore (particle size ratio: 1.83), mixed coke is mixed with these, and the coarse-grained ore is charged in the first batch by reverse tilting. did. As a result, Invention Example 3 has a higher gas utilization rate than Comparative Example 5 in which coarse-grained ore is charged in the first batch under the same conditions by forward tilting, the pressure loss of the packed bed is reduced, and the reducing agent ratio and the reducing agent ratio are reduced. The coke ratio has been reduced.
　発明例２、３および比較例５との比較から、２バッチ目の細粒鉱石の傾動方向が順傾動であっても逆傾動であっても、１バッチ目の粗粒鉱石を逆傾動で装入することで、１バッチ目の粗粒鉱石を順傾動で装入した場合より還元材比およびコークス比が低減できることがわかる。これらの結果から、鉱石を粗粒鉱石と細粒鉱石とに分け、それぞれに混合コークスを混合し、１バッチ目に逆傾動で混合コークスが混合された粗粒鉱石を装入することで、高炉操業における還元材比およびコークス比を低減できることが確認された。 From the comparison with Invention Examples 2 and 3 and Comparative Example 5, the coarse-grained ore of the first batch is loaded with the reverse tilt regardless of whether the tilting direction of the fine-grained ore of the second batch is forward tilting or reverse tilting. It can be seen that the reducing agent ratio and the coke ratio can be reduced as compared with the case where the coarse-grained ore of the first batch is charged in a forward tilting manner. Based on these results, the ore was divided into coarse-grained ore and fine-grained ore, mixed coke was mixed with each, and the coarse-grained ore mixed with mixed coke was charged in the first batch by reverse tilting to blast furnace. It was confirmed that the reducing agent ratio and coke ratio in operation can be reduced.
　さらに、２バッチ目の混合コークスが混合された細粒鉱石を順傾動で装入した発明例３は、同じ条件で２バッチ目の混合コークスが混合された細粒鉱石を逆傾動で装入した発明例２よりも還元材比およびコークス比が低減した。この結果から、２バッチ目の混合コークスが混合された細粒鉱石を逆傾動で装入することで、高炉操業における還元材比およびコークス比をさらに低減できることが確認された。 Further, in Invention Example 3 in which the fine-grained ore mixed with the second batch of mixed coke was charged by forward tilting, the fine-grained ore mixed with the second batch of mixed coke was charged by reverse tilting under the same conditions. The reducing agent ratio and the coke ratio were reduced as compared with Invention Example 2. From this result, it was confirmed that the reducing agent ratio and the coke ratio in the blast furnace operation can be further reduced by charging the fine-grained ore mixed with the mixed coke in the second batch by reverse tilting.
　鉱石を粗粒鉱石と細粒鉱石とに分割し、１バッチ目に粗粒鉱石を装入し、２バッチ目に細粒鉱石を装入した比較例２、４は、鉱石を粗粒鉱石と細粒鉱石に分割しないで装入した比較例１よりも還元材比およびコークス比が低減した。一方、比較例２、４は混合コークスを混合していないので還元反応性が劣り、このため、比較例３、５よりも還元材比およびコークス比が増加した。 In Comparative Examples 2 and 4, in which the ore was divided into a coarse-grained ore and a fine-grained ore, the coarse-grained ore was charged in the first batch, and the fine-grained ore was charged in the second batch, the ore was regarded as the coarse-grained ore. The reducing material ratio and the coke ratio were reduced as compared with Comparative Example 1 in which the ore was charged without being divided into fine-grained ores. On the other hand, in Comparative Examples 2 and 4, since the mixed coke was not mixed, the reduction reactivity was inferior, and therefore, the reducing agent ratio and the coke ratio were increased as compared with Comparative Examples 3 and 5.
　実施例１と同じ高炉を使用して、鉱石を３バッチで装入して、出銑比２．０の条件で操業した例を表２に示す。粗粒鉱石と細粒鉱石の篩分けも実施例１と同様に平均粒径比１．３５と１．８５の２種類の条件とした。比較例１１および発明例１１～２４の測定条件および測定結果を下記表２に示す。 Table 2 shows an example in which the same blast furnace as in Example 1 was used, the ore was charged in 3 batches, and the operation was performed under the condition of a tapping ratio of 2.0. The sieving of coarse-grained ore and fine-grained ore was also set under two conditions, that is, an average particle size ratio of 1.35 and 1.85, as in Example 1. The measurement conditions and measurement results of Comparative Example 11 and Invention Examples 11 to 24 are shown in Table 2 below.
Figure JPOXMLDOC01-appb-T000002
  
Figure JPOXMLDOC01-appb-T000002
  
　表２における「Ｏ１傾動方向」は、１バッチ目に装入する鉱石の装入シュートの傾動方向を示す。「Ｏ２傾動方向」は、２バッチ目に装入する鉱石の装入シュートの傾動方向を示す。「Ｏ３傾動方向」は、最終バッチである３バッチ目に装入する鉱石の傾動方向を示す。傾動方向における「順」は、装入シュートを順傾動させて鉱石を装入したことを示し、「逆」は、装入シュートを逆傾動させて鉱石を装入したことを示す。 "O1 tilting direction" in Table 2 indicates the tilting direction of the ore charging chute charged in the first batch. The “O2 tilting direction” indicates the tilting direction of the ore charging chute charged in the second batch. The “O3 tilting direction” indicates the tilting direction of the ore charged in the third batch, which is the final batch. "Forward" in the tilting direction indicates that the charging chute was tilted forward to charge the ore, and "reverse" indicates that the charging chute was tilted in the reverse direction to charge the ore.
　比較例１１および発明例１１、１２では、鉱石を粗粒鉱石と細粒鉱石とに分割（粒径比１．３５）し、これらに混合コークスを混合した。比較例１１では、１バッチ目、２バッチ目の各バッチを粗粒鉱石とし、３バッチ目は細粒鉱石とし、いずれも順傾動で装入した。これに対して発明例１１では、１バッチ目に粗粒鉱石を逆傾動で装入し、２バッチ目は粗粒鉱石を逆傾動で装入し、３バッチ目に細粒鉱石を順傾動で装入した。発明例１２では、１バッチ目に粗粒鉱石を逆傾動で装入し、２バッチ目は細粒鉱石を順傾動で装入し、３バッチ目に細粒鉱石を順傾動で装入した。発明例１１、１２のいずれの場合も比較例１１に比べてガス利用率が高くなり、充填層の圧力損失が減少し、還元材比およびコークス比が低減した。なかでも、２バッチ目を逆傾動で装入した発明例１１の方が順傾動で装入した発明例１２よりも還元材比およびコークス比が低減し、より好ましいことが確認された。 In Comparative Example 11 and Invention Examples 11 and 12, the ore was divided into coarse-grained ore and fine-grained ore (particle size ratio 1.35), and mixed coke was mixed therewith. In Comparative Example 11, each batch of the first batch and the second batch was a coarse-grained ore, and the third batch was a fine-grained ore, all of which were charged in a forward tilting manner. On the other hand, in Invention Example 11, coarse-grained ore was charged in the first batch by reverse tilting, coarse-grained ore was charged in the second batch by reverse tilting, and fine-grained ore was charged in the third batch by forward tilting. I charged it. In Invention Example 12, coarse-grained ore was charged in the first batch by reverse tilting, fine-grained ore was charged in the second batch by forward tilting, and fine-grained ore was charged in the third batch by forward tilting. In both cases of Invention Examples 11 and 12, the gas utilization rate was higher than that of Comparative Example 11, the pressure loss of the packed bed was reduced, and the reducing agent ratio and the coke ratio were reduced. Among them, it was confirmed that Invention Example 11 in which the second batch was charged in the reverse tilt was more preferable because the reducing agent ratio and the coke ratio were reduced as compared with Invention Example 12 in which the second batch was charged in the forward tilt.
　発明例１３から発明例２４では、粗粒鉱石と細粒鉱石との篩分けを目開き１０ｍｍ（平均粒径比１．８５）の篩を用いて行なった。発明例１３から２４のいずれも、１バッチ目は粗粒鉱石を逆傾動で装入した。 In Invention Examples 13 to 24, sieving of coarse-grained ore and fine-grained ore was performed using a sieve having an opening of 10 mm (average particle size ratio 1.85). In all of Invention Examples 13 to 24, coarse-grained ore was charged in the first batch by reverse tilting.
　発明例１３から発明例１６では、２バッチ目を細粒鉱石、３バッチ目を粗粒鉱石として、２バッチ目、３バッチ目の装入シュートの傾動方向をそれぞれ逆、順とした４パターンで原料を装入した。発明例１３から発明例１６のいずれの場合も比較例１１よりもガス利用率が高くなり、充填層の圧力損失が減少し、還元材比およびコークス比が低減した。 In Invention Examples 13 to 16, the second batch is a fine-grained ore, the third batch is a coarse-grained ore, and the tilting directions of the charging chutes of the second and third batches are reversed and ordered in four patterns. The raw materials were charged. In each of Invention Example 13 to Invention Example 16, the gas utilization rate was higher than that of Comparative Example 11, the pressure loss of the packed bed was reduced, and the reducing agent ratio and the coke ratio were reduced.
　発明例１７から発明例２０では、２バッチ目を粗粒鉱石、３バッチ目を細粒鉱石として、２バッチ目、３バッチ目の装入シュートの傾動方向をそれぞれ逆、順とした４パターンで原料を装入した。発明例１７から発明例２０のいずれの場合も比較例１１よりもガス利用率が高くなり、充填層の圧力損失が減少し、還元材比およびコークス比が低減した。なかでも、３バッチ目を順傾動で装入した発明例１８、２０は、３バッチ目を逆傾動で装入した発明例１７、１９に比べて、ガス利用率が高く、充填層の圧力損失が減少しており、より好ましいことが確認された。 In Invention Examples 17 to 20, the second batch is a coarse-grained ore, the third batch is a fine-grained ore, and the tilting directions of the charging chutes of the second and third batches are reversed and ordered in four patterns. The raw materials were charged. In each of the cases of Invention Example 17 to Invention Example 20, the gas utilization rate was higher than that of Comparative Example 11, the pressure loss of the packed bed was reduced, and the reducing agent ratio and the coke ratio were reduced. Among them, Invention Examples 18 and 20 in which the third batch was charged in the forward tilt have a higher gas utilization rate and pressure loss in the packed bed than in Invention Examples 17 and 19 in which the third batch was charged in the reverse tilt. Was reduced, confirming that it was more preferable.
　発明例２１から発明例２４では、２バッチ目、３バッチ目をいずれも細粒鉱石として、２バッチ目、３バッチ目の装入シュートの傾動方向をそれぞれ逆、順とした４パターンで原料を装入した。発明例２１から発明例２４のいずれの場合も比較例１１よりもガス利用率が高くなり、充填層の圧力損失が減少し、還元材比およびコークス比が低減した。なかでも、３バッチ目を順傾動で装入した発明例２２、２４は、３バッチ目を逆傾動で装入した発明例２１、２３に比べて、ガス利用率が同等か高く、充填層の圧力損失が減少しており、より好ましいことが確認された。 In Invention Examples 21 to 24, the raw materials are used in four patterns in which the second and third batches are all fine-grained ores, and the tilting directions of the charging chutes of the second and third batches are reversed and in order, respectively. I charged it. In each of Invention Example 21 to Invention Example 24, the gas utilization rate was higher than that of Comparative Example 11, the pressure loss of the packed bed was reduced, and the reducing agent ratio and the coke ratio were reduced. Among them, Invention Examples 22 and 24 in which the third batch was charged in the forward tilt have the same or higher gas utilization rate than Invention Examples 21 and 23 in which the third batch was charged in the reverse tilt, and the filling layer It was confirmed that the pressure loss was reduced, which was more preferable.
　１０　コークス層
　１２　粗粒鉱石層
　１４　細粒鉱石層 10 coke layer 12 coarse-grained ore layer 14 fine-grained ore layer

Claims (2)

  1. 　装入シュートを有するベルレス装入装置を用いて鉱石と混合コークスとの混合物を２バッチ以上に分割して高炉内に装入する高炉への原料装入方法であって、
    　前記鉱石を粗粒鉱石と、前記粗粒鉱石よりも平均粒径が小さい細粒鉱石とに分け、前記粗粒鉱石に混合コークスを混合して混合コークスが混合された粗粒鉱石とし、前記細粒鉱石に混合コークスを混合して混合コークスが混合された細粒鉱石とし、
    　少なくとも１バッチ目に高炉の半径方向における炉中心と炉壁との中間点よりも炉中心側から炉壁側へ前記装入シュートを傾動させて前記混合コークスが混合された粗粒鉱石の全部または一部を装入する、高炉への原料装入方法。     It is a method of charging raw materials into a blast furnace in which a mixture of ore and mixed coke is divided into two or more batches and charged into the blast furnace using a bellless charging device having a charging chute.
    The ore is divided into a coarse-grained ore and a fine-grained ore having an average particle size smaller than that of the coarse-grained ore. Mixed coke is mixed with grain ore to make fine-grained ore mixed with mixed coke.
    At least in the first batch, all of the coarse-grained ore mixed with the mixed coke by tilting the charging chute from the furnace center side to the furnace wall side from the midpoint between the furnace center and the furnace wall in the radial direction of the blast furnace, or A method of charging raw materials into a blast furnace, in which a part is charged.
  2. 　最終バッチで前記高炉の半径方向における炉中心と炉壁との中間点よりも炉壁側から炉中心側へ前記装入シュートを傾動させて前記混合コークスが混合された細粒鉱石の全部または一部を装入する、請求項１に記載の高炉への原料装入方法。 In the final batch, all or one of the fine-grained ores mixed with the mixed coke by tilting the charging chute from the furnace wall side to the furnace center side from the midpoint between the furnace center and the furnace wall in the radial direction of the blast furnace. The method for charging a raw material into a blast furnace according to claim 1, wherein the portion is charged.
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