JP2000336417A - Method for setting tuyere - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a setting method of a tuyere, with which the perfect separation and high smelting capacity can be obtd., in the case of separating and recovering zinc and iron from an electric furnace dust. SOLUTION: In the case of charging raw material, such as the electric furnace dust, through a tuyere at the upper stage in a vertical furnace which has two stages of tuyeres at the upper and the lower stages and fills coke, a reduction capacity is calculated from the raw material blowing quantity per unit surface area of the coke in a columnar smelting zone between raceways in the fronts of the tuyeres at the upper and the lower stages. Then, the cross sectional area of the raceway, with which both of the number of the tuyeres and the distance between the tuyeres at the upper and the lower stages sufficiently satisfy the smelting capacity, is obtd., and on the result, the number of the tuyeres is set. The above reduction capacity is regulated to <=0.0002 t/h/m2 and the number of the tuyeres is reversely calculated from gas speed at the front of the tuyere deciding the cross sectional area of the raceway.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a carbon-based solid reducing material packed bed furnace for filling a carbon-based solid reducing material such as coke with at least two upper and lower tuyeres. The present invention relates to a method of setting the number of tuyeres of a furnace in which a charged material is charged and operated.

[0002]

2. Description of the Related Art A furnace developed for efficiently melting chromium steel, for example, can be applied as a carbon-based solid-reducing-material-packed-bed furnace provided with such two-tiered tuyeres. That is, when a sufficient amount of heat for melting cannot be obtained with only the upper tuyere, the lower tuyere supplements the amount of heat and sufficiently melts the meantime.

As a method of setting the number of tuyeres of such a furnace, for example, Japanese Unexamined Patent Publication No. Hei 6-330 proposed by the present applicant has been proposed.
No. 126 is described. In this tuyere setting method, the operating conditions are set so that the distance between adjacent raceways is 300 mm or more. This is based on the theory that if the distance between adjacent raceways is less than 300 mm, they may be connected to each other, and if so, the smelting reduction reaction performed in the raceways becomes unstable.

[0004]

Normally, the amount of heat required for smelting is determined for a predetermined amount of blowing, and the amount of blowing gas supplied to all tuyeres is determined. At this time, when the number of tuyeres that blow gas increases, the amount of gas blown from each tuyere decreases, and the raceway decreases. Setting the number of tuyeres only for the purpose of widening the raceway interval as in the conventional tuyere setting method can be achieved by reducing the raceway, and in order to do so, increase the number of tuyeres. Will be.

[0005] On the other hand, in a furnace filled with a carbon-based solid reducing material, reducing the amount of gas blown into the tuyere also reduces the reducing ability. That is, injecting the blowing gas from the upper and lower two-stage tuyeres also means performing a reduction by giving a sufficient amount of heat between the raceways in front of the upper and lower two-stage tuyeres. The iron melts and drops and accumulates in the hearth. As described above, most of the iron component in the powdery granular material charged into the upper tuyere is an oxide, and iron oxide that is not reduced remains in the slag and is not recovered. In other words, an unreasonable increase in the number of tuyeres leads to a reduction in the reducing capacity and a reduction in the recovery rate of pig iron, that is, a reduction in the production capacity.

The present invention has been developed in order to solve the above-mentioned problems, and it is possible to improve the reducing ability, to sufficiently separate and recover highly volatile metals such as zinc, and to improve the productivity of pig iron. It is an object to provide a tuyere setting method.

[0007]

According to a first aspect of the present invention, there is provided a tuyere setting method comprising at least two upper and lower tuyeres and at least an upper tuyere. A method for setting the number of tuyeres of a carbon-based solid reducing material packed bed furnace in which a powdery and granular material is charged and filled with a carbon-based solid reducing material, wherein a cross section of a raceway of an upper tuyere is a bottom. The number of tuyeres and the interval between the upper and lower tuyeres to achieve the required smelting capacity are set based on the amount of raw material per unit surface area of the carbon-based solid reducing material in the cylinder having the height between the upper and lower tuyeres. It is characterized by the following.

The present inventors have paid particular attention to the point that zinc and iron are completely separated and recovered from electric furnace dust containing zinc, and have intensively studied to solve various problems that occur specifically.
At this time, it has been found that the above-described problem occurs, and that it can be solved by setting the number of tuyeres. In other words, when the total amount of injected gas is fixed,
As the number of tuyeres increases, the amount of gas blown from each tuyere decreases, and the raceway decreases. This relationship is unique.

On the other hand, it has been found that the reducing ability is determined in the smelting region between the raceways in front of the upper and lower tuyeres. That is, for example, the iron oxide melted in the raceway in front of the upper tuyere receives heat from the raceway in front of the lower tuyere while dripping to the raceway in front of the lower tuyere. It is reduced to pig iron by contact with the system-based solid reducing agent. Therefore, the reducing capacity during this period is based on the assumption that a cylinder whose bottom is the cross section of the raceway and whose height is the distance between the upper and lower tuyeres, and which can contact the total surface area of the carbon-based solid reducing material therebetween. What is necessary is just to prescribe | regulate the insertion amount. However, since this cylinder contains the parameter of the distance between the upper and lower tuyeres, in addition to the cross-sectional area of the raceway simply determined by the number of tuyeres, for example, the distance between the upper and lower tuyeres,
In other words, when the heights of the cylinders are different, it is necessary to evaluate each height.However, for each condition of the height, the amount of the raw material injected per unit surface area of the carbon-based solid reducing material in the cylinder is determined. If evaluated, the reduction ability at that height can be evaluated. The unit surface area of the carbon-based solid reducing agent refers to the average surface area per unit volume of the carbon-based solid reducing agent such as coke.

According to a second aspect of the present invention, in the tuyere setting method according to the first aspect of the present invention, the cylinder having the cross section of the raceway as a bottom and the distance between the upper and lower tuyeres as a height. it is characterized in setting the blade number of units and the upper and lower tuyeres interval raw material blowing amount per unit surface area of the carbonaceous solid reducing agent in the inner as follows 0.0002t / h / m ^2.

According to the present invention, for example, when treating electric furnace dust containing zinc and iron, zinc is separated and recovered from exhaust gas from the furnace top and a sufficient pig iron production capacity is secured. It defines the numerical values necessary to perform

[0012]

Embodiments of the present invention will be described below. FIG. 1 shows a vertical smelting reduction furnace (hereinafter simply referred to as a vertical furnace) to which the furnace operating method of the present invention is applied. This vertical furnace 1 is filled with a solid reducing material 2 such as coke, and constitutes a solid reducing material packed bed type smelting reduction furnace as a whole. The vertical furnace 1 is provided with at least two upper and lower tuyeres. As the vertical furnace 1 provided with the tuyeres 3 and 4 in the upper and lower stages in this manner, for example, a furnace developed for efficiently melting chromium ore can be applied. That is, when sufficient heat amount for smelting reduction cannot be obtained with only the tuyere 3 in the upper stage, the heat amount is supplemented from the tuyere 4 in the lower stage and the smelting reduction is sufficiently performed during that time. The number of tuyeres 3 and 4 may be set, for example, from the reducing capacity and the melting capacity to achieve the required smelting capacity, which is determined according to the depth of the raceway in front of each tuyere or the cross-sectional area. Is done.

In these tuyeres 3 and 4, hot air and oxygen-enriched air are used as blowing gas from a blower 5 through a hot air generating furnace 6. This is because oxygen is required to burn the solid reducing material 2 in the furnace and use the combustion heat for melting, burning, evaporating, reducing, etc. the raw material, and also heats the blown gas. In this case, the sensible heat of the blown gas can be used as a form of heat input into the furnace.

On the other hand, a raw material is blown into the upper tuyere 3 from a raw material blowing device 7. The raw material blown from the tuyere 3 at the upper stage is basically limited to a granular material, and melts, burns, reduces and evaporates immediately after blowing. Of this raw material,
Oxides and hydroxides of low-volatile metals such as molten iron are reduced in the process of dropping the packed bed of the solid reducing material, and accumulate in the hearth. The vapor of the highly volatile metal such as zinc that evaporates rises to the furnace top through the gap of the solid reducing material 2 and is discharged together with the furnace gas as described later.

Powdery and granular raw materials, such as electric furnace dust, which are zinc-containing dusts, are in principle blown from the upper tuyere 3. Since the powdery and granular material is light, when it is charged from the furnace top, the low volatile metal is sufficiently melted and dropped into the packed bed of the solid reducing material 2 by the ascending airflow in the furnace, for example, as described above. Since the material is blown off before and is discharged from the furnace top as it is, the granular material is blown from the tuyere 3 in the upper stage in order to prevent the discharge. In other words, the powdery and granular material is
It must be melted immediately in the raceway in front of the upper tuyere 3 to be blown.

On the other hand, since the massive raw material has a large weight, it does not blow off even if it receives a rising airflow in the furnace. In addition, since this kind of bulk raw material does not need to be instantaneously melted in front of the tuyere as described above, the raw material is charged from the furnace top by the furnace top charging device 8 in principle. In addition, as described later, in the present embodiment, it is necessary to maintain the temperature of the furnace top at a high temperature, but if a large amount of bulk material is charged at once, the temperature of the furnace top may be too low. Therefore, the bulk material is charged continuously in principle, so that the temperature at the furnace top does not decrease. More specifically, it is preferable to charge continuously by a charging pipe system from the furnace top. Of course, even if a large amount of bulk raw material is charged at a time, it is sufficient that a sufficient amount of heat is obtained and the furnace top temperature can be maintained high. Also, when the bulk material is pulverized into powder and granules, it should be blown from the tuyere 3 in the upper stage.

In this embodiment, in order to keep the temperature of the furnace top high, a secondary combustion gas is supplied to the space of the furnace top and intentionally burned in the furnace top. The secondary combustion gas is also supplied to the inside of the duct for discharging the exhaust gas from the furnace top and burned in the duct. However, when the secondary combustion gas is burned, carbon dioxide is generated. In the present embodiment, the furnace top is included, and exhaust gas cooling and cooling is performed from the furnace top.
It is necessary to reduce the oxygen potential in the duct leading to the cleaning device in accordance with the temperature. For this purpose, it is necessary to measure the gas temperature and the composition and strictly control the supply amount of the secondary combustion gas.

The exhaust gas discharged from the furnace top in this way is sent into the exhaust gas cooling / cleaning device 9. The exhaust gas cooling / cleaning device 9 is specifically a wet cooling device, that is, a liquid is sprayed in the exhaust gas to lower the temperature of the exhaust gas, to cool and solidify a substance in a vapor state, and to drip together with the liquid. Precipitation is performed so that it can be separated and recovered as a slurry, and gas that does not liquefy or solidify is collected as a gas. In this embodiment,
As described later, a highly volatile metal such as zinc is solidified and separated and recovered from the exhaust gas, and the discharged exhaust gas is obtained as a high-calorie fuel gas containing a carbon monoxide gas. In addition, by rapidly cooling such high-temperature exhaust gas, re-synthesis of dioxin which is a harmful substance contained in the raw material can be prevented.

Next, in the solid reduction material packed bed type smelting reduction furnace as described above, iron oxides and hydroxides, which are low volatile metals, and zinc oxides and hydroxides, which are high volatile metals, are mainly used. The following describes conditions for using a powdery material such as electric furnace dust as a zinc-containing dust as a charging material, separating and recovering it into iron and zinc, and simultaneously extracting a high-calorie fuel gas.

In recent years, the amount of generated iron scrap containing zinc, such as surface-treated steel sheets for automobiles, has been increasing. In an electric furnace or the like using this iron scrap as a main raw material, dust containing zinc and iron as main components is generated. At present, because of high collection costs, this dust is detoxified after dust collection, and then dumped to landfill. However, the content of zinc contained in the electric furnace dust is 20 to 30%, and the same amount of iron is also contained. These forms may be oxides or hydroxides, but the amount of dust generated is as large as 15 kilograms per ton of steel, low cost and no waste, and each is collected in a completely separated state. There is a need for technology to do this.

Here, an example of the composition of the raw material is shown in Table 1.
As is clear from the table, it contains a considerable proportion of iron and zinc, and also contains calcium oxide, silica, alumina and the like.

[0022]

[Table 1]

Next, the operating conditions are shown in Table 2. here,
The oxygen-enriched hot air shall be blown from the tuyere, and the powdery and charged raw materials shall also be blown from the tuyere.

[0024]

[Table 2]

As described above, the powdery and granular charge material is blown from the tuyere (the upper tuyere in the case of having at least two tuyeres). If the temperature in front of the tuyere is low, the iron component to be separated and collected by melting and dropping is not sufficiently melted,
It is blown off by the rising air current in the furnace, discharged from the furnace top, and taken out by the exhaust gas cooling / cleaning device. In other words, iron will be mixed into the slurry in the exhaust gas cooling / cleaning apparatus where only zinc is to be separated and recovered. It has been found that the temperature before the tuyere, especially the temperature before the tuyere for blowing the powdery and granular raw materials, greatly contributes to this. FIG. 2 shows the relationship between the temperature in front of the injection tuyere and the concentration of iron contained in the slurry in the exhaust gas cooling / cleaning device (in the figure, the concentration of iron in the solid content).

As is clear from the figure, the concentration of iron contained in the slurry was such that the temperature before the injection tuyere was 1500 ° C.
In the above region, the size becomes smaller. In other words, the tuyere temperature is 15
If the temperature is set to 00 ° C. or higher, the iron content in the powdery granular material is immediately melted and dropped in front of the tuyere, and therefore, it is considered that a small percentage of the iron is blown off by the rising airflow in the furnace.
Further, by setting the temperature before the blowing tuyere to 1700 ° C. or higher, the melting can be further promoted. Once melted in this way, the molten iron drops into the solid reducing material layer, is reduced during that time, and accumulates in the hearth. Therefore, if it is taken out, high-purity iron can be separated and recovered.

On the other hand, when gaseous zinc reacts with carbon dioxide, solid zinc oxide and carbon monoxide are produced. This reaction is a reversible reaction. As the temperature is lower or the oxygen potential is higher, solid zinc oxide is easily generated. When the temperature in the furnace and from the furnace top to the exhaust gas duct is low, or the oxygen potential is large, solid zinc oxide cannot reach the exhaust gas cooling / manufacturing device and adheres to the furnace wall or duct wall. If the amount becomes extremely large, the duct or the furnace may be closed, and the operation may not be continued.

The factors governing the reaction are temperature and oxygen potential. The oxygen potential is an index indicating the degree of oxidizing property of the atmosphere. Since the atmosphere at the top of the furnace is almost exclusively carbon dioxide and carbon monoxide, specifically, CO + 1
/ 2O ₂ = free energy change of reaction of CO ₂ ΔG ° = -67150 + 20.37 (T + 273) (ca
l) is defined by the following equation obtained from When the relationship between the oxygen potential and the temperature of the furnace top is examined by substituting the reaction heat necessary for the reaction, a single curve (substantially a straight line) shown in FIG. 3 is obtained. In the region where the oxygen potential is lower or the temperature is higher than this, gaseous zinc is stable. That is, the zinc state of the gas can be maintained in the lower left region of the curve in the figure. This area is given by the following two equations.

Log (Po ₂ ) = 2 log (Pco ₂ / Pco) − 29386 / (T + 273) +8.914 (1) log (Po ₂ ) ≦ −48138 / (T + 273) +25.35 (25) 2) However, T: Atmosphere temperature in the furnace or furnace top (° C) Po ₂ : Oxygen potential (atm) In addition to these conditions, the temperature of the furnace top is set to 730 ° C or more as a temperature condition in which zinc is further stabilized as a gas. did. Further, it is desirable that the gas temperature T (° C.) and the oxygen potential Po ₂ (atm) at the furnace top before the secondary combustion are in the region surrounded by the following three equations. The reason for this is that the adhesion of zinc oxide is reduced even in the part near the charging surface at the furnace top, the adhesion of zinc oxide in the furnace is eliminated, and there is no need to perform secondary combustion. This is because, even in the case of performing combustion, excessively high-temperature combustion gas is not generated, and it is not necessary to excessively reduce the oxygen potential.

T ≧ 730 ° C. log (Po ₂ ) ≦ −29386 / (T + 273) +6.51 (3) When operating while satisfying these conditions, zinc oxide adheres from the furnace top to the exhaust gas duct. In addition, it is possible to separate and recover zinc and iron as described above, and at the same time, it is possible to collect high-calorie fuel gas. On the other hand, if the conditions were not satisfied, the zinc oxide adhering to the furnace wall clogged the furnace in about one to two weeks, and the operation could not be continued. In order to control these conditions, the amount of air blown from the tuyere, the amount of oxygen enriched, the coke ratio changed by adjusting the feed rate of the raw material, the execution of secondary combustion at the furnace top and duct, and the secondary combustion The main means was gas conditioning.

Next, a method for setting the tuyere for satisfying the above conditions and achieving sufficient smelting reduction of iron and separation and recovery of zinc was examined. In other words, when the total amount of gas blown from the tuyere is determined, the amount of gas blown from each tuyere decreases as the number of tuyeres increases, and the amount of heat generated in the raceway should decrease. That's why. here,
For example raceways feather preoral shape, considered to be circular as shown in FIG. 4, the area of the cross section of the raceways and S _r, the depth, i.e. the diameter of the raceways and D _r Then, the cross-sectional area _Sr is expressed by the following five equations.

[0032] ^{_{S r = π · D r 2}} /4 (m 2) ......... (5) On the other hand, the depth (diameter) D _r of said raceways, appears in a well-known following equation (6). D _r = 0.375 · (ρ _g / (φ · ε ³ · ρ _p ) ^0.5 · U ₀ · D _t / (g · D _p ) ^0.5 (m) ……… (6) where φ is the shape factor (− ) Ε: porosity (−) ρ _g : blown gas density (kg / m ³ ) ρ _p : coke apparent density (kg / m ³ ) D _p : coke charging diameter (m) U ₀ : gas in front of tuyere Velocity (m / s) D _t : Tuyere inner diameter (m) Further, the gas velocity U ₀ before the tuyere is expressed by the following equation using the number of tuyeres n.

U ₀ = (B _v + Eo ₂ ) / n × (B _t +273) /273×1.033/ (B _p +1.033) × 4 / (π · D _t ² ) (7) _Bv : Air volume (Nm ³ / s) Eo ₂ : Enriched oxygen volume (Nm ³ / s) B _t : Air temperature (° C.) B _p : Tuyere pressure (kg / cm ² G). That will reduce the blade preoral gas velocity U ₀ An increase wings talkative n, also decreases the cross-sectional area S _r raceways simultaneously.

On the other hand, as shown in FIG. 4, the iron oxide melted in the raceway in front of the upper tuyere is heated up to the raceway in front of the lower tuyere and comes into contact with the carbon-based solid reducing material. It is reduced by this and accumulates in the hearth as pig iron.
That is, it can be said that this area is a smelting area. If the reducing capacity of this smelting area is not sufficient, the iron oxide remains in the slag and the smelting capacity is relatively reduced. The reducing ability of the smelting zone is determined by the total surface area of the carbon-based solid reducing material in the smelting zone. Therefore, this smelting region is regarded as a column having the cross-sectional area of the raceway as the bottom, and the relationship between the total surface area of the carbon-based solid reducing material present in the volume and the concentration of iron oxide recovered from the slag is described. investigate. The total surface area of the carbon-based solid reducing agent in this smelting region is determined by using the carbon-based solid reducing agent (coke) surface area a per unit volume, the distance (height) H between the upper and lower tuyeres, and the number of tuyere sets n. , S _r
・ It is expressed by H ・ a ・ n. However, what is to be evaluated here is not the melting ability of the entire columnar smelting area, but the reducing ability per unit surface area of coke in the smelting area. In other words, what we are trying to set here is the total return capacity to achieve the required smelting capacity, which requires the cross-sectional area of the raceway, which varies with the number of tuyeres. , The required smelting capacity for each height of the cylinder, that is, for each distance between the upper and lower tuyeres,
By dividing by the reduction capacity per unit surface area of coke in the smelting area, the cross-sectional area of the raceway can be obtained, and the number of tuyere can be set based on that. Therefore, the total raw material injection amount W
_d (t / day) coke total surface area S _r of the smelting area
The figure shows the relationship between the raw material injection amount W _d / ( _Sr · Ha · n) per unit surface area of coke in the smelting area divided by H · a · n and the iron oxide concentration (%) in the slag. It is shown in FIG. As is clear from the figure, the raw material injection amount W _d / (S _r · H · a · n) per unit surface area of coke in the smelting area is 0.
In the region of 0002 t / h / m ² or less, the iron concentration in the slag product is 1.5% or less. That is, in this region, the molten iron oxide is almost completely reduced, and the smelting region including the raceway has a sufficient reducing ability.

Next, as described above, W _d / (S _r · H · a
・ N) = 0.002 t / h / m ² The reduction capacity and the number of tuyeres in the smelting area set from 0.0002 t / h / m ² (in the figure, the number of tuyere sets, the set of upper and lower tuyeres are shown, and are substantially the same as the number of tuyeres) FIG. 6 shows the relationship between the two. The distance H between the upper and lower tuyeres is
Two types of 2.0m and 2.5m, inner diameter of tuyere is 0.08m
Think at. As shown in the figure, when the required smelting capacity per day is 35 t, the number of tuyere sets is set to 1 at the interval between the upper and lower tuyeres of 2.0 m.

Here, the concept of the inner diameter of the tuyere will be described.
As can be seen from the above equation (6), it is considered effective to increase the gas velocity by reducing the inner diameter of the tuyere in order to increase the raceway and increase the reducing ability. However, it is known that if the gas velocity is increased excessively, the impact on the coke increases and the generation of coke powder increases. In the coke packed bed, generation of powder must be avoided as much as possible because it causes a decrease in ventilation and liquid permeability and a deterioration in operation. When ordinary coke is used, it is safe to keep the tuyere wind speed at 200 m / s or less in order to suppress an increase in the amount of generated coke powder.

Further, it is necessary to insert a lance for injecting the raw material from the upper tuyere, so that an inner diameter of at least 0.08 m is required. FIG. 7 shows the relationship between the tuyere inner diameter and the tuyere wind speed in this embodiment.
In this case, even with one tuyere set, the tuyere wind speed does not exceed 200 m / s when the inner diameter is 0.08 m or more, and 0.08 m is adopted as the tuyere inner diameter.

[0038]

As described above, according to the tuyere setting method according to the first aspect of the present invention, the inside of the cylinder having the cross section of the raceway as the bottom and the distance between the upper and lower tuyeres as the height is provided. From the amount of raw material injected per unit surface area of the carbon-based solid reducing material, to determine the number of tuyeres and the upper and lower tuyere intervals to achieve the required smelting capacity, the carbon-based solid reducing material in the cylinder By evaluating the amount of raw material that can be contacted, the conditions under which it can be sufficiently reduced can be satisfied and the reduction capacity can be improved, thereby sufficiently separating and recovering highly volatile metals such as zinc and producing pig iron. It can also improve the performance.

Further, according to the tuyere setting method according to the second aspect of the present invention, the carbon-based solid reducing material in a cylinder having a cross section of a raceway as a bottom and a distance between upper and lower tuyeres as a height. Of raw material per unit surface area is 0.0002t
/ H / m ² or less and the number of tuyeres and the interval between upper and lower tuyeres are set. Therefore, when treating electric furnace dust containing zinc and iron, zinc is separated and recovered from exhaust gas from the furnace top and sufficient pig iron Production capacity can be secured.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a furnace to which a tuyere setting method of the present invention is applied.

FIG. 2 is an explanatory diagram showing a relationship between a tuyere front temperature and a concentration of iron collected and contained in exhaust gas from a furnace top.

FIG. 3 is an explanatory diagram of a region controlled by a furnace top temperature and an oxygen potential.

FIG. 4 is an explanatory diagram of a smelting region between upper and lower raceways.

FIG. 5 is an explanatory diagram showing a relationship between a raw material injection amount per unit surface area of coke in a smelting region and an iron oxide concentration in slag.

FIG. 6 is an explanatory diagram for setting the number of tuyere and the upper and lower tuyere intervals for achieving the reducing ability.

FIG. 7 is an explanatory diagram of a relationship between a tuyere inner diameter and a tuyere wind speed.

[Explanation of symbols]

 1 is a vertical furnace 2 is a carbon-based solid reducing material 3 is an upper tuyere 4 is a lower tuyere 5 is a blower 6 is a hot air generator 7 is a raw material injection device 8 is a furnace top charging device 9 is an exhaust gas cooling / Cleaning equipment

Continued on the front page (72) Inventor Masato Mizuto 1-chome, Kawasaki-dori Mizushima, Kurashiki-shi, Okayama Pref. (No address) F-term in Kawasaki Steel Corporation Mizushima Works (reference) 4K001 AA08 AA10 AA30 BA14 BA22 EA05 GA01 GB03 HA01 4K012 CB04

Claims (2)

[Claims] 1. A carbon-based solid reducing material-filled bed type having at least two tuyeres at the upper and lower stages, charging a granular charge material from at least the upper tuyeres, and filling the carbon-based solid reducing material. A method of setting the number of tuyeres of a furnace, wherein the raw material per unit surface area of the carbon-based solid reducing material in a cylinder having a cross section of a raceway of an upper tuyere as a bottom and a distance between the upper and lower tuyeres as a height. A method for setting the number of tuyeres, wherein the number of tuyeres and the interval between upper and lower tuyeres to achieve a required smelting capacity are set based on the amount of tuyere. 2. The raw material injection amount per unit surface area of the carbon-based solid reducing material in a cylinder whose bottom is a cross section of the raceway and whose height is the distance between the upper and lower tuyeres is 0.0002.
tuyere setting method according to claim 1, characterized in that setting the blade number of units and the upper and lower tuyeres interval as t / h / m ² or less.