JPH09125112A - Method for mixing and charging ore and coke into ball-less blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate the melting of ore by improving the air permeability of ore layers alternately formed with coke layers in a blast furnace. SOLUTION: The ore (O) and the coke (C) are discharged from a furnace top hopper in the state of mixing part thereof onto the coke layer of >=5 to <=25 deg. in the angle θ of surface inclination lowering from the peripheral part of the furnace toward the central part of the furnace formed in the furnace prior to charging of the ore in the stage of charging the ore into the blast furnace. While the coke is allowed to segregate again on the ore flowing on the base of a swiveling chute 14, the core is charged by tilting the chute 14 from the central part toward the peripheral part of the furnace, by which the resegregated coke layer C1 formed in a lit form longitudinally on the ore layer O charged into the furnace is distributed in the radial direction of the furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for charging ore and coke into a furnace alternately in layers from a furnace top hopper arranged in a bellless charging device of a blast furnace through a turning chute.

[0002]

2. Description of the Prior Art A raw material charging device for a blast furnace is roughly classified into a bell-type charging device, a furnace top hopper, and a bellless-type charging device having a swirling chute. Input devices are becoming mainstream. In the bellless charging device, the raw material charged in the furnace top hopper can be charged into any position in the radial direction of the blast furnace by using a swirling chute. In ordinary charging, ore as an iron raw material, fuel, and coke as a reducing agent are alternately charged into the furnace to form ore layers and coke layers alternately in the furnace.

Generally, the ore and coke charged in the blast furnace 1 as shown in the schematic cross-sectional view of the solid flow shown in FIG. 8 is a reduced powder of the ore with the layer structure of the ore layer O and the coke layer C being maintained. As shown in the flow line A, the inside of the shaft is lowered while being changed. That is, the coke charged in the furnace peripheral region 3 in the blast furnace 1 descends toward the raceway 6 formed by the hot air blown from the tuyere 4. Incidentally, in order to save expensive coke charged from the furnace top, it is actively practiced to blow auxiliary fuel such as pulverized coal from the tuyere 4 together with hot air.

Charges such as coke drop in a complicated manner represented by a squirrel-like flow into the upper part of the raceway 6 in front of the tuyere 4 and stagnation of the load down at the furnace core. In this way, the fusion zone 5 is formed by the balance of the respective heat velocities of the falling charge and the rising gas, and the hot metal 10 and the slag 11 are pooled in the hearth 9 via the dropping zone 7. . Hearth 9
The accumulated hot metal 10 is discharged to the outside of the furnace from the tap hole 8 together with the slag 11.

By the way, when the ore and the coke are charged alternately into the furnace as described above, the so-called mixed charging for mixing the coke in the ore layer to promote the reduction and melting of the iron ore. A technique (Japanese Patent Laid-Open No. 62-127413) is known. Iron ore is heated, reduced, softened, and melted in the blast furnace, and finally becomes hot metal and is discharged to the outside of the furnace.However, when the amount of gas flowing in the bed decreases due to softening and contraction of the ore, the reduction stops. At the same time, a problem that melting and dropping are delayed becomes apparent. In the mixed charging technique of mixing coke with ore, coke existing in the ore layer in a dispersed state prevents softening and shrinkage of the ore and improves the air permeability in the layer. In the above-mentioned mixed charging technique (Japanese Patent Laid-Open No. 62-127413), a highly reactive coke having a reactivity index of 30% or more is contained in the ore layer formed in the furnace with respect to the total amount of coke charged. It is characterized by being present in the range not exceeding 30%. Further, the highly reactive coke is formed horizontally in a layer in the ore layer or dispersed in the ore layer.

Further, Japanese Patent Laid-Open No. 62-260010 discloses a method of charging a mixed raw material of iron ore and coke into a bellless type blast furnace and dispersing them uniformly in the furnace.
The weight ratio of the reducing agent in the mixed raw material is constant or controlled over time, and the tilting angle of the swirling chute is controlled to charge the mixed raw material from the central part of the furnace toward the furnace wall and to the interior of the furnace. Mixing of the bellless blast furnace characterized by controlling at least one of the tilt angle of the swirling chute, the number of turns at each tilt angle, and the lower gate valve opening degree so that the subsequent deposition angle of the raw material does not exceed 20 degrees. It is a charging method.
It is reported that the coke can be uniformly dispersed in the ore layer by performing such control.

[0007]

SUMMARY OF THE INVENTION The above conventional mixing and charging technique has a low injection amount of auxiliary fuel such as pulverized coal and heavy oil,
The weight ratio of ore (O) and coke (C) charged from the top of the furnace (hereinafter O / C) has been effective under operating conditions with a relatively low level. On the other hand, from the experience of operation, it is not possible to obtain sufficient ventilation improvement even with mixed charging when the coke ratio is 350 kg / t or less (O / C 4.7 or more) due to the recent large amount of pulverized coal injection (150 kg / t or more). It has become clear.

The coke mixed in the ore becomes a resistance against shrinkage and deformation of the ore, and promotes the reduction reaction of the ore by converting the CO ₂ generated by the reduction of the ore into CO by the reaction of the formula (1). doing. C + CO ₂ → 2CO (1) The reason why highly reactive coke is used as the coke mixed in the ore layer is that the reaction of the formula (1) can be promoted.

When a large amount of pulverized coal is blown, char particles derived from pulverized coal which has not been burnt in the raceway rise in the furnace together with the gas, and the ore layer or the ore is softened and melted near the cohesive zone. Trapped in the landing zone. Unburned char contributes to ore reduction by the reaction of Eq. (1), and is consumed at the same time as mixed coke. Since the unburned char reactivity is much higher than the reactivity of coke, the mixed coke becomes unreacted and the effect of improving ventilation is not sufficiently exhibited. In addition, when a large amount of pulverized coal is injected, the O / C of the charging raw material is increased, and the ore layer thickness is relatively increased. As a result, it was clarified that the ventilation of the ore layer was deteriorated, and the ventilation was deteriorated especially when the ore melted down.

At the time of burning, the ore layer is almost completely fused and the amount of gas flowing in the layer is extremely small. The amount of heat for melting the ore is supplied by conduction heat transfer from the gas flowing in the coke layer around it. Therefore, it is difficult to improve the melting of the softened cohesive zone by the conventional mixed charging, although the ventilation of the softened cohesive zone is somewhat improved. As described above, it is difficult for the conventional mixed charging method to exert a sufficient effect for the reasons described above. Further, the charging method for realizing the mixed charging, JP-A-60-260010, also aims at the uniform dispersion of coke in the layer, so that it is difficult to sufficiently exert the effect. .

[0011]

[Means for Solving the Problems] When the ore softening, changes in the gas flow that governs burn-through after fusing, and heat transfer phenomena were examined in detail, the following points were revealed. (1) The amount of gas flowing in the cohesive zone is extremely small, and the influence of the gas flow on heat transfer dissolution is small.

(2) The delay in dissolution of the ore layer at high O / C is due to slow conduction heat transfer in the thick cohesive zone. Therefore, the dissolution rate can be improved by reducing the ore layer thickness. (3) Heat transfer in the cohesive zone can be promoted by forming a coke slit having good ventilation in the longitudinal direction in the cohesive zone.

The present invention aims to improve the dissolution rate of the ore layer at high O / C, particularly paying attention to the above (3).
Specifically, a coke layer with good ventilation is formed in the ore layer in the longitudinal direction in the shape of stripes to provide a coke slit with low ventilation resistance, and a gas flowing therethrough promotes melting and a charging method is realized. It is provided to the concrete charging means for doing.

That is, the present invention according to claim 1 is a method for charging ore and coke in layers alternately from a furnace top hopper arranged in a bellless charging device of a blast furnace through a turning chute, At the stage of charging the ore into the furnace, the surface inclination angle θ that decreases from the peripheral area of the furnace formed in the furnace toward the center of the furnace before charging the ore is on the coke layer of 5 degrees or more and 25 degrees or less. , The ore (O) and a part of the coke (C) are discharged from the furnace hopper in a mixed state, and the choke is re-segregated on the ore flowing through the swirling chute from the central part of the furnace to the peripheral part. by charging tilts toward, the ore layer were charged into the furnace, the furnace radial width thickness DW _f longitudinal re segregation coke layer formed in a slit shape of the charging level dimensionless re segregation layer width thickness dimensionless by a furnace port radius R _O The W _f / R _O as 0.01 to 0.04, the ore in the bell-less blast furnace, characterized in that to distribute the furnace radial direction, a coke mixed charging method.

According to a second aspect of the present invention, in the method for charging ore and coke into the furnace alternately in layers from a furnace top hopper arranged in a bellless charging device of a blast furnace through a turning chute, the furnace is used. At the stage of charging the ore into the furnace, from the furnace top hopper, onto the coke layer with a surface inclination angle θ of less than 5 degrees that decreases from the furnace peripheral part formed in the furnace toward the furnace center before charging the ore The ore (O) and a part of the coke (C) are discharged in a mixed state, the coke is re-segregated on the ore flowing through the swirling chute, and the chute is tilted from the central part of the furnace toward the peripheral part. A dimensionless raw material position distance DR in which the raw material falling distance DR _f is made dimensionless by the furnace opening radius R _O at the charging position.
_f / R _O was charged so as to satisfy the following conditional expression, and the width or thickness DW _f in the furnace radial direction of the re-segregated coke layer formed in a slit shape in the longitudinal direction was added to the ore layer contained in the furnace interior. Ore and coke in a bellless blast furnace characterized by dimensionless re-segregation layer width thickness DW _f / R _O dimensionlessized by the charging level furnace radius R _O of 0.005 or more and less than 0.01 It is a mixed charging method.

Dimensionless raw material falling position interval DR _f > 0.04-0.008 × (surface inclination angle of coke layer formed before ore charging) The present invention according to claim 3 is for an ore layer charged in a furnace. The method of mixing ores and coke in a bellless blast furnace according to claim 1 or 2, wherein the re-segregated coke layers formed in a slit shape in the longitudinal direction are distributed in three or more locations in the furnace radial direction. .

[0017]

FIG. 5 shows the charging method of the mixed raw material of ore and coke in the bellless blast furnace 1. Ore (O) and coke (C) are charged as raw materials into one of the two furnace top poppers 12 using a charging belt conveyor from an ore tank (not shown) and a coke tank installed on the ground. , Ore (O) and coke (C) are simultaneously discharged from the furnace top hopper 12 for mixed charging. As a means for carrying out the mixed charging, as shown in the figure, ore and coke are loaded into the same hopper 12 and discharged, and then loaded into upper and lower two layers or multiple layers, or as shown in FIG. A method in which the coke (C) is stored in separate hoppers 12 at the top of the furnace and mixed and charged by discharging the coke at the same time is conceivable, but there is no particular limitation, and before charging the raw materials to the top hopper 12. The ore and coke may be mixed in advance. Furnace top hopper
The ore (O) and the coke (C) discharged from 12 are stacked on the furnace top 15 by a swirling chute 14 that rotates while maintaining a predetermined angle via a collecting chute 13. The charges are stacked in the furnace for each turning, and finally an ore layer O and a coke layer C are formed. It should be noted that C in FIGS.
Reference numeral ₁ denotes a slit-shaped re-segregation coke layer formed in the ore layer O.

The behavior of the raw materials discharged from the swirling chute 14 during the mixed charging is shown in FIGS. On the swirling chute 14, the heavy ore layer O ₂ having a small particle size slowly flows at the bottom of the chute, and the coke layer C ₁ having a large particle size and lightly flows on the upper surface of the ore layer O _{1 having} a medium particle size at a high speed. . As a result, the resegregated coke layer C where the coke falls further
₁ appears. FIGS. 1 to 4 show the results of examining the coke deposition behavior by changing the tilt angle change direction of the turning chute, the size of the change, and the shape of the lower surface in this state. As shown in FIG. 4, when the tilting angle of the swirling chute 14 is changed from the tilting direction generally indicated by the arrow, that is, when the peripheral portion of the furnace is changed to the central portion of the furnace, the resegregated coke C _{1 is} attached to the furnace wall. Since it is pushed into the center of the ore and deposited again in the center of the furnace, it is not possible to form slit-like longitudinally segregated coke slits in the ore layer, and a re-segregated coke layer C ₁ is formed in the center of the furnace. To do. On the other hand, when the tilt angle of the swirling chute is changed in the opposite direction from the central part of the furnace toward the peripheral part of the furnace and the surface tilt angle of the lower coke layer C and the change width of the tilt angle of the swirling chute are properly set, the results shown in FIG. Thus, the ore layer O containing the re-segregated coke layer C ₁ of the present invention in a slit shape (streak shape) can be formed in the ore layer O.

As shown in FIG. 2, when the surface slope of the lower coke layer C is gentle and the swirling chute 14 is changed from the peripheral portion of the furnace to the central portion of the furnace, the charging position at the time of the previous turning and the charging position at this time approach each other. In this case, the resegregation coke layer C ₀ at the time of the previous turn is swept toward the furnace wall by the falling flow of the charge, and it is difficult to form an appropriate resegregation coke layer C ₁ as shown in FIG. become. Therefore, the re-segregated coke layer for each turning is swept away and gathered to form a single coke layer on the furnace wall. On the other hand, as shown in FIG. 3, when the surface slope of the lower coke layer C is tight, the raw material charged in each swirl does not remain in the charging position but flows into the central portion to form the resegregated coke layer C ₁ . Since it is formed, an appropriate resegregation coke layer cannot be obtained.

In the present invention, as shown in FIG.
Change the tilt angle from the center of the furnace to the periphery of the furnace.
And the surface inclination angle θ of the lower coke layer C is properly adjusted.
Slit-like re-segregation coke in ore layer O
Layer C₁Can be distributed annularly in the radial direction of the furnace
You. In FIG. 1, the surface of the coke layer C before charging the ore
Inclination angle θ, distance R from the furnace center to the material drop position_fIn
Then, from the turning chute 14 on the coke layer C every turning
Raw material drop containing ore and coke in the radial direction of the furnace
Lower position interval DR_fAnd a vertical slit-like re-segregation
Arks layer C₁Width and thickness of DW_fAnd like this
Material drop position interval DR_fRadius R at the drop position_Oso
Dimensionless dimensionless material drop position interval DR_f/ R_OAnd
And resegregation coke layer C₁Width thickness DW _fAlso the furnace mouth half
Diameter R_ODimensionless re-segregation coke layer width thickness D
W_f/ R_OIs defined.

The conditions for forming the slit-like re-segregated coke layer C ₁ optimum for improving the ventilation as shown in FIG. 1 in the ore layer O were investigated. That is, the surface inclination angle θ at which the lower coke layer C before the ore charging decreases from the furnace peripheral portion toward the furnace central portion is defined as the dimensionless raw material falling position interval DR _f / R.
_O and the dimensionless re-segregation coke layer width thickness DW _f / R _O formed in the ore layer O were evaluated. FIG. 7 shows the result. In FIG. 7, a circle indicates a sufficient dimensionless re-segregation coke layer width thickness DW _f / R _{O in the} ore layer O which has a slit shape in the longitudinal direction.
= 0.01-0.04 is formed, Δ is an acceptable DW _f
/ R _O = 0.005 to less than 0.01 is formed, and ● indicates that DW _f <0.005 where the resegregation coke layer is not sufficiently formed.

As shown in FIG. 7, if the surface inclination angle θ of the coke layer C before ore charging is 5 ° or more and 25 ° or less, a sufficient or acceptable dimensionless resegregation coke layer width / thickness can be obtained. Recognize. Further, when the surface inclination angle θ of the coke layer C before ore charging is less than 5 degrees, the dimensionless raw material falling position interval DR _f / R
Area above the straight line connecting _O = 0.04 and inclination angle θ = 5 degrees,
That is, the dimensionless material drop position interval DR _f > 0.04−0.008 ×
It shows that at least an acceptable DW _f / R _o = 0.005 to less than 0.01 can be obtained (the surface inclination angle of the coke layer formed before ore charging).

On the other hand, the dimensionless material falling position interval DR _f / R
_O = 0.04 and surface inclination angle θ of coke layer C before ore charging =
In the region below the line connecting the 5 degrees, coke flows into the peripheral area of the furnace, and the dimensionless re-segregation coke layer width thickness DW _f / R _O <0.005 is obtained, and the proper re-segregation coke is generated in the ore layer O. It hardly forms the layer C ₁ and does not contribute to the improvement of ventilation.

The re-segregation coke layer C ₁ formed in the ore layer O does not necessarily have to be formed for each turn of the turning chute 14, and the portion where the ore layer O is considered to be insufficiently melted is not necessarily formed. 3 in the radial direction of the specific area around the center
It is preferable to form so as to be distributed in more than one place, preferably in more than six places. The average layer ore layer O charged to the normal from the turning chute 14 on the coke layer C thickness H (see FIG. 1) is a furnace port radius R _O in dimensionless dimensionless ore layer thickness H /
Since R _O = 0.1, the raw material drop position furnace port radius R _O = 54
In the case of 0 cm, the average ore layer thickness H = R _O × 0.1 = 54 cm.

In order to improve the ore meltability in the radial portion where the ore layer O is insufficiently melted, that is, in the region where the dimensionless distance is 0.3,
Positional distance DR _f <less than dimensionless ore layer thickness H = 54 cm
It is necessary to form the coke resegregation layer C ₁ with H (= 54 cm). That is, a radial area corresponding to a dimensionless distance of 0.3 = 540 cm × 0.3 = 162 cm from the turning chute 14 (16
2/54 = 3) It is necessary to form the re-segregated coke layer C ₁ at least at three places by turning three times. Furthermore, in order to improve the heat transfer melting rate, it is desirable to form the resegregated coke layers C ₁ at 6 or more places.

To form the re-segregated coke layer C ₁ in a specific region of the ore layer O in the radial direction, for example,
As shown in FIG. 6, it becomes possible by controlling the timing of discharging the ore (O) and the coke (C) stored in the two furnace top hoppers 12, respectively. That is, first, the ore (O) may be discharged from the furnace top hopper 12, and the coke (C) may be discharged from another furnace top hopper 12 when the turning chute 14 reaches a specific area.

[0027]

[Examples] Table 1 shows the results of carrying out the mixed charging method of the present invention in a large bellless blast furnace having an inner volume of 4500 m ³ and a furnace diameter of 5.3 m. It is a blast furnace with two parallel bunkers on the top of the furnace. A swirling chute with a chute length of 4.0 m is used to load one batch of ore and coke into the furnace in 13 swirls.
The tilt angle of the turning chute was set at 52.5 degrees as 1 point and 13 degrees as 14 points, and the points were divided at equal intervals. Fuel ratio is 480kg / t to 510kg /
It is between t and a large amount of pulverized coal is injected. As the mixed charging coke, about 80 kg / t of coke having a particle size of 15-50 mm and the same size as the normal coke was charged. The ore was charged into the top hopper, and then the same hopper was charged with the mixing coke and simultaneously discharged.

[0028]

[Table 1]

In Comparative Example 1, a coke surface (coke terrace) having an inclination angle of 0 was formed on the furnace wall, and a mixed coke layer was formed thereon. The length of the coke terrace is 1.5 m
Because it is short, the dimensionless material drop position interval during mixed charging is 0.
03 and short. As a result, mixed coke is concentrated and deposited near the furnace wall, making it difficult to form a longitudinal coke layer in the ore layer. As a result, the pressure loss in the lower part of the blast furnace was as large as 0.029 kg / m ³ and the fluctuation of the ventilation resistance was σΔP.
As / v is 0.030, it can be seen that the fluctuation of the operation is large. At the same time it becomes difficult to maintain the hot metal temperature above 1500 ° C,
The fluctuation of [Si] in the hot metal is also extremely large.

In Comparative Example 2, the length of the coke terrace on the furnace wall was shortened to 0.5 m, and the mixed raw material was mixed on the slope of the coke (angle).
(26 degrees) charged up. Although the distance between the non-dimensional raw material dropping positions during the mixed charging is as large as 0.05, the charged mixed raw material does not stay at the charging position near the furnace wall but flows into the central part of the furnace. At the same time, the coke in the mixed raw material was re-segregated in the furnace, and the mixed coke was concentrated and deposited in the center of the furnace. as a result,
It can be seen that the pressure loss in the lower part of the blast furnace is as large as 0.030 kg / m ³ and the fluctuation σΔP / v of the ventilation resistance is 0.028, indicating that stable operation is not possible. At the same time, it becomes difficult to maintain the hot metal temperature above 1500 ° C, and at the same time, the utilization rate of the gas at the top of the furnace decreases, and the fuel ratio is forced to rise to 520 kg / t.

In Example 1, a coke surface (coke terrace) having an inclination angle of 5 degrees was formed on the furnace wall, and a mixed coke layer was formed on the coke surface. Length of coke terrace 2.
Since the length was increased to 5 m, the distance between the non-dimensional material dropping positions during mixed charging could be set to a large 0.04. As a result, the mixed raw material charged in the vicinity of the furnace wall was, as shown in FIG.
Longitudinal slit-like re-segregation coke layer C ₁ in the ore layer
Is formed. As a result, the softening and melting of the cohesive zone are promoted, resulting in a decrease in the pressure loss in the lower part of the blast furnace to 0.020 kg / m ³ and a change in ventilation resistance σΔP / v to 0.018.
Stable operation was realized. It became possible to maintain the hot metal temperature as high as 1503 ° C, and the pulverized coal injection rate could be increased to 200 kg / t, and at the same time the fuel ratio could be reduced to 490 kg / t.

In Example 2, the length of the coke terrace on the furnace wall was shortened to 0.5 m, and the mixed raw material was charged on the slope of the coke (angle 15 °). The distance between the dimensionless raw material dropping positions during the mixed charging was increased to 0.05, and at the same time, the charging pattern of the coke was adjusted so that the inclination angle of the lower surface was 20 degrees. Since the coke inclination angle was in the appropriate range, the charged mixed raw material remained at the charging position, and a stable deposited layer as shown in FIG. 1 was formed. As a result, the pressure loss in the lower part of the blast furnace decreased to 0.018 kg / m ³ and the fluctuation of the ventilation resistance σΔP / v was 0.015, enabling stable operation. At the same time, it became possible to maintain the hot metal temperature as high as 1505 ° C, and the amount of pulverized coal injected was 20%.
It was able to increase up to 5kg / t and at the same time reduce the fuel ratio to 480kg / t.

In this embodiment, the ore was charged into the furnace top hopper, and then the mixed coke was charged into the same hopper and discharged simultaneously. However, the mixed coke is charged into different hoppers and discharged simultaneously with the ore. Is also possible. Further, as the mixed coke, a coke having an air permeability close to that of a normal coke is used, but it is also possible to use a coke having a small particle size with high reactivity as is conventionally done.

[0034]

As described above, according to the present invention, the dissolution rate of the ore charged in the blast furnace is reduced when the production capacity of coke is reduced, when the coke ratio is low, when the coke ratio is low, and when pulverized coal is blown in large amounts. By increasing the re-segregation coke layer by utilizing the ventilation improving effect, it is possible to further reduce the coke ratio and stabilize the operation.

When the amount of coke produced in a steel mill is insufficient, it is generally common to purchase coke from the market to supplement it, but the price of market coke is about 50% higher than that of self-produced coke. The economic effect of the present invention, which can reduce the amount used, is great. Also, by improving the breathability,
As shown in the examples, the amount of tapped metal can be increased and the production amount of the entire steel mill can be increased.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing in cross section a case where an appropriate resegregation coke layer is formed in an ore layer by charging a raw material according to the present invention.

FIG. 2 is an explanatory view showing in cross section a case where an appropriate resegregation coke layer is not formed by charging a raw material in Comparative Example 1.

FIG. 3 is an explanatory view showing in cross section a case where an appropriate resegregation coke layer is not formed by charging a raw material in Comparative Example 2.

FIG. 4 is an explanatory view showing in cross section a case where an appropriate resegregation coke layer is not formed by charging a raw material in a conventional example.

FIG. 5 is an explanatory view showing a cross section of a case where ore and coke are simultaneously discharged from the same furnace top hopper according to the present invention and charged through a swirling chute.

FIG. 6 is an explanatory view showing a cross section of a case where ores and coke are simultaneously discharged from different furnace top hoppers according to the present invention and charged through a swirling chute.

FIG. 7 shows the relationship between the surface inclination angle θ at which the lower coke layer before the ore charging decreases from the furnace peripheral portion toward the furnace central portion and the dimensionless raw material falling position interval DR _f / R _O formed in the ore layer. 2 is a graph evaluated from the dimensionless re-segregation coke layer width thickness DW _f / R _o .

FIG. 8 is an explanatory view schematically showing in cross section the effect status of the conventional raw material in the blast furnace.

[Explanation of symbols]

 1 Blast Furnace (Bellless Blast Furnace) 2 Furnace Center Area 3 Furnace Peripheral Area 4 Tuyere 5 Fusing Zone 6 Raceway 7 Dripping Zone 8 Tap Hole 9 Hearth Floor 10 Molten Iron 11 Slag 12 Top Chopper 13 Collecting Chute 14 Swing Chute 15 Top of the furnace A Flow line C Coke layer O Ore layer

Claims (3)

[Claims] 1. A method of charging ore and coke into a furnace alternately in layers from a furnace top hopper arranged in a bellless charging device of a blast furnace through a swirling chute, wherein the ore is charged into the furnace. Then, the ore (O) from the furnace top hopper is placed on the coke layer having a surface inclination angle θ of 5 degrees or more and 25 degrees or less that decreases from the furnace peripheral part formed in the furnace toward the furnace center part before the ore charging. And a part of the coke (C) are discharged in a mixed state, and the chute is charged while being re-segregated on the ore flowing in the swirling chute while tilting from the central part of the furnace toward the peripheral part. To the ore layer charged in the furnace,
Longitudinally dimensionless repolarization dimensionless by a furnace port radius R _O of the charging level width thickness DW _f of the furnace radial re segregation coke layer formed in a slit shape segregation layer width thickness DW _f / R _O
A method for mixing ores and coke in a bellless blast furnace, which is characterized by being distributed in the radial direction of the furnace as 0.01 to 0.04. 2. A method of charging ore and coke into a furnace alternately in layers from a furnace top hopper arranged in a bellless charging device of a blast furnace through a swirling chute, wherein the ore is charged into the furnace. In addition, the ore (O) and the coke (C) are fed from the furnace top hopper onto the coke layer having a surface inclination angle θ of less than 5 degrees which decreases from the furnace peripheral portion toward the furnace central portion formed in the furnace before charging the ore. ) Is discharged in a mixed state, and coke is re-segregated on the ore flowing through the swirling chute, and the chute is tilted from the central part of the furnace toward the peripheral part to charge the raw material drop interval DR _f . The dimensionless raw material position distance DR _f / R _{O, which} is made dimensionless by the furnace radius R _O of the position, is charged so as to satisfy the following conditional expression, and a longitudinal slit is formed in the ore layer contained in the furnace. the furnace radial width thickness DW _f re segregation coke layer formed instrumentation Dimensionless Re segregation layer width dimensionless by the level of the furnace opening radius R _O thickness DW _f / R _O 0.005
A method for mixing ores and coke in a bellless blast furnace, characterized in that the content is distributed in the radial direction of the furnace with a value of less than 0.01. Note Dimensionless raw material drop position interval DR _f > 0.04−0.008 × (surface inclination angle of coke layer formed before ore charging) 3. A resegregation coke layer formed in a slit shape in the longitudinal direction is formed in the ore layer charged in the furnace in a radial direction of 3 in the furnace.
A method for charging ore and coke in a bellless blast furnace, which is characterized in that it is distributed in more than one place.