KR101598362B1 - Method and apparatus for operating blast furnace - Google Patents

Abstract

The present invention discloses a blast furnace operating method and a blast furnace operating apparatus. According to the present invention, in the blast furnace operation in which a raw material and fuel are charged through an upper portion of a blast furnace to produce a molten iron, a fluidity improving material is introduced into the blast furnace to decrease the viscosity of the slag generated during the production of the molten iron A blast furnace operating method and apparatus are provided.
According to the present invention, the slag fluidity improving material (powdery material containing Na and K) is directly blown through the blast furnace to directly affect the slag, whereby the slag viscosity can be quickly lowered by 10 to 15% 70 ~ 100 ℃ lower. By reducing the slag viscosity and melting point in such a short time, the amount of the slag staying in the furnace can be solved to help the outlet work, and the flow resistance can be reduced by securing the flow path in which the gas inside the furnace can relatively rise It is possible to facilitate aging recovery.

Description

[0001] METHOD AND APPARATUS FOR OPERATING BLAST FURNACE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blast furnace operation method and a blast furnace operation apparatus, and more particularly, to a blast furnace operation method and a blast furnace operation apparatus capable of increasing the fluidity of slag generated during blast furnace operation.

The steel industry is a core industry that supplies basic materials to all industries such as automobiles, shipbuilding, home appliances, and construction. In general, iron ore (sintering, sintering, pellets) and coke are charged into the blast furnace, and hot air and hot gases such as oxygen at 1,150 ° C There is a blast furnace process in which molten iron (pig iron) is produced by reducing iron ore after injection.

The hot air and oxygen blown into the tuyeres burn the fuel such as coke in the blast furnace to generate the reducing gas. The generated high-temperature reducing gas rises in the blast furnace to heat and reduce the iron ore while the iron ore is melted do. The generated iron (pig iron) and slag are discharged to the outside through the exit port at the bottom of the blast furnace at regular intervals, and then transferred to the steelmaking process by the TLC.

On the other hand, in order to produce high-quality charcoal, it is preferable to use a stabilizing light having a high content of iron (Fe) and a low content of other impurities. However, due to the continuous consumption of stabilizing light, To replace this, most of the recent blast furnace processes depend on sinter ores.

Sintered ore refers to artificial ores made by sintering minute iron ore (heating to 1,200 ~ 1,300 ° C to semi-molten state and bonding by spectroscopy by recrystallization or melting).

The sintering method most widely used for producing such sintered ores is a method in which a minute iron ore, an auxiliary material, a semitransparent material and a binder used as a sintering and mixing material are quantitatively cut out from a plurality of raw material reservoirs, laminated on a belt conveyor and transported, In water and firing in a sintering machine to produce sintered ores.

That is, the above-mentioned manufacturing method is a method suitable for mass production, in which fluxes of raw materials of 8 mm or less and fluxes such as limestone, silica sand and serpentine as raw materials and coke and anthracite fuel are mixed at a predetermined ratio Mix thoroughly in a mixer and add water to adjust the water content to about 6 to 7% to attach and granulate fine particles around the particles having a large particle size (construction: fine particles having a particle size of 0.2 mm or less, To be a pseudo-particle.

In this way the like iron making process of making the molten iron using iron ore as a main raw material, since the recent iron (Fe) of the containing ratio of the high high-quality iron ore subjected to being depleted, and the impurity of the iron ore because the choice but to use iron ores of Low Grade (SiO _2, Al ₂ O _3, etc.) content is gradually increasing. Furthermore, iron ores having a high iron (Fe) content have a significantly higher price than iron ores having a low content of iron (Fe).

On the other hand, the purpose of the steelmaking process is to produce good quality wire at a low cost by the amount required in the post-process. Therefore, recently, an impurity such as by the purpose of reducing the manufacturing costs of the established light depletion and molten iron (SiO _2, Al ₂ O _3, etc.) there is the content is increased ore the amount of the higher cost, so that impurities from the slag in particular, Al ₂ O ₃ The total absolute volume (volume) of the slag in the blast furnace is increasing. As a result, the slag melting temperature increases and the slag viscosity also increases.

Moreover, as the Al ₂ O ₃ content ratio increases, the viscosity of the slag increases sharply, and the discharge of the molten slurry is not smooth, which may cause deterioration of the purity of the slag and ventilation in the furnace.

FIG. 1 is a graph showing the change in slag viscosity with increasing Al ₂ O ₃ content ratio in blast furnace slag at 1,450 ° C.

The content of Al ₂ O ₃ in the slag in a conventional blast furnace is about 13-18%, which is usually controlled to be 18% or less.

As the content of Al ₂ O _{3 in the} blast furnace slag increases, the slag viscosity increases at the same basicity (CaO / SiO ₂ ratio), and the temperature at which the slag becomes solidified increases, leading to an increased risk of slag clogging .

Accordingly, in order to increase the fluidity of the slag, the molten metal temperature is raised or the basicity of the slag is lowered to lower the solidification temperature of the slag. Or limestone and serpentinite are used in the production of sintered ore used in the blast furnace, and the sintered ores contain the CaO and MgO components, which are slag fluxes, and are melted in the furnace to produce a slag having low melting point and low viscosity (CaO / SiO ₂ ) to produce slag at a level of 1.0 to 1.2.

If the basicity (CaO / SiO ₂ ratio) of the slag is lowered, the slag can be maintained in a liquid state at a low temperature and discharged to the outside. In the course of lowering the basicity (CaO / SiO ₂ ratio) It is necessary to use a large amount of the slag, so that the absolute amount of the slag to be loaded in the bottom of the blast furnace is increased, which leads to an increase in reduction ratio and aeration resistance.

That is, in order to facilitate the discharge of slag, the volume (kg / tp) of the blast furnace slag is increased by the amount of CaO and MgO, which are added in the production of the autocrystalline sintered ore, There is a problem that the reducing agent ratio is increased because an additional heat source is required for melting.

As a result, when the molten iron temperature falls below 1,400 ° C or the content of Al ₂ O ₃ in the slag increases due to an increase in the ratio of the iron ore used, which has a high content of impurities (Al ₂ O ₃ ), the slag viscosity increases sharply, Had a limitation in lowering the slag viscosity so that it could be discharged to the outside.

That is, when the furnace sulfur content is changed, the time for which the charged materials stay in the furnace generally increases, so that the content of silicon (Si) in the molten iron increases, so that CaO / SiO ₂ in the slag tends to rise sharply, Difficult to discharge.

Conventionally, researches for improving the viscosity of slag have been continued. That is, conventionally, the ratio of the major components constituting the slag (the MgO content ratio, the basicity, which means the [CaO content ratio / SiO2 content ratio]) is changed by changing the components of the slag by putting the pulverized coal and the slag- To improve the fluidity.

However, such a conventional technique may be effective in improving the flow of slag in the short term, but the overall absolute amount of the slag present in the blast furnace is not reduced but rather increased, which may cause a deterioration in the efficiency of the blast furnace in the long term.

Accordingly, the present invention is not limited to improving the viscosity of slag by adjusting the basicity through addition of SiO ₂ , CaO, Al ₂ O ₃ , or MgO, which are the main components of slag, but by using components other than the main constituent constituting the slag There is provided a blast furnace operation apparatus and a blast furnace operating apparatus which fundamentally improves the fluidity of slag by reducing the total absolute amount of slag present in the blast furnace irrespective of the basicity (C / S) of the slag by improving the fluidity by breaking the coupling of the slag It has its purpose.

That is, according to the present invention, the slag fluidity improving material (powdery material containing Na and K) is blown into the upper part of the blast furnace or tuyeres to directly act on the slag, thereby achieving a slag viscosity of 10 to 15 %, And the melting point can be lowered by 70 to 100 ° C, so that even when a low-cost iron ore having a high content ratio of impurities (Al ₂ O ₃ ) is used, the outgassing of slag can be smoothly carried out, And a blast furnace operating device

The blast furnace operation method according to an embodiment includes: a feedstock / feedstock supply step of supplying a fuel and a feedstock in a blast furnace; And a flowability improving material supplying step of supplying a flow improving material for increasing the flowability of the slag, wherein the flow improving material comprises an alkaline-based compound and is introduced into the blast furnace in the form of an oxide, And dissociating the slag structure.

According to one embodiment, the flowability improving material is characterized in that the tetrahedral bond of SiO ₂ and Al ₂ O ₃ of the slag is broken and replaced with an alkali-based element.

According to one embodiment, the flow improver may be blown up to the top of the blast furnace, and preferably blown into the blast furnace.

According to one embodiment, there is provided a fuel injection system comprising: a fuel crushing step of crushing fuel below a set particle; A pulverized coal supply step of transferring the pulverized pulverized fuel to the furnace side of the blast furnace; And a fluidity improving material supplying step of supplying the fluidity improving material to be mixed with the pulverized coal at the time of transferring the pulverized coal.

According to one embodiment, the fuel crushing step is characterized by crushing the fuel to 0.5 mm or less.

According to one embodiment, the fluidity improving material supply step is characterized in that 1 to 10t / hr of fluidity improving material is supplied per 1 to 150t / hr of pulverized pulverized coal.

According to one embodiment, at least two distributors are alternately connected to a plurality of stator troughs; And sequentially introducing the fluidity improving material-containing fine powder into the blast furnace from each distributor.

According to one embodiment, the method may further include a transfer gas supplying step of supplying a transfer gas for transferring the fine coal and the flow improver to the blast furnace side.

According to one embodiment, the transport gas is any one of inert gas selected from Ar, He, and N gas.

According to an embodiment of the present invention, the conveying gas supplying step supplies an inert gas at a pressure of 1 to 20 kg / cm 2.

According to one embodiment, the alkali-based compound is any one selected from Na2CO3, Na2CO4, NaHCO3, (NaPO3) 6 and CaF2.

According to one embodiment, the flow improver is in powder form.

A blast furnace operating apparatus according to an embodiment includes: a fuel hopper for supplying fuel; A fuel crusher for crushing the fuel to a set particle or less; A storage hopper for storing the pulverized pulverized fuel; A plurality of feed tanks alternately supplied with the differentiated fuel from the storage hopper; A flow improvable material supply unit for mixing the fluidity improving material with the pulverized fuel; And a distributor for distributing the mixed fuel and the flow improver into a plurality of blast furnace tuyers.

According to an embodiment, the distributor is divided into a first distributor and a second distributor, and the first distributor and the second distributor are alternately connected to a plurality of blast-furnace tuyeres, respectively.

According to one embodiment, a transfer gas supply unit may be further provided between the feed tank and the distributor to feed the transfer gas for transferring the process material.

According to one embodiment, the transport gas is an inert gas.

According to an embodiment of the present invention, a plurality of pulverized coal feed tanks are provided between the storage hopper and the distributor so as to supply pulverized coal alternately.

According to one embodiment, the fluidity improving material supply unit is configured to supply the fluidity improving material to the plurality of pulverized coal feed tanks.

According to one embodiment, a cyclone is installed between the fuel crusher and the storage hopper.

According to one embodiment, a fuel silo for primarily storing fuel supplied to the fuel hopper; And a fluidity improving material silo for primarily storing the fluidity improving material supplied to the fuel hopper.

According to the present invention, the slag fluidity improving material (powdery material containing Na, K, P, F and Mn) is directly blown through the blast furnace to directly affect the slag, 10 to 15% lower and melting point can be lowered by 70 to 100 ° C. By reducing the slag viscosity and melting point in such a short time, the amount of the slag staying in the furnace can be solved to help the outlet work, and the flow resistance can be reduced by securing the flow path in which the gas inside the furnace can relatively rise It is possible to facilitate aging recovery.

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In other words, the present invention does not improve the viscosity of the slag by adjusting the basicity through addition of SiO ₂ , CaO, Al ₂ O ₃ , and MgO, which are the main components of the slag, but uses components other than the main constituent constituting the slag The flowability of the slag can be improved by reducing the overall absolute amount of the slag present in the blast furnace irrespective of the basicity (C / S) of the slag.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing viscosity change of blast furnace slag with increasing Al ₂ O ₃ content ratio. FIG.
Figure 2 shows the Al ₂ O ₃ dissociation mechanism in the slag upon addition of the flow improver.
3 is a graph showing the viscosity change of the slag upon addition of the flow improver.
4 is a schematic view showing a blast furnace operating apparatus according to a first embodiment of the present invention;
5 is a schematic view showing a blast furnace operation apparatus according to a second embodiment of the present invention;
6 is a schematic view showing a blast furnace operation apparatus according to a third embodiment of the present invention.
7 is a table showing the relationship between the content of Al ₂ O ₃ and the slag fluidity in the blast furnace slag according to the embodiment of the present invention.
8 is a graph showing the relationship between the Al ₂ O ₃ content and the slag fluidity in the blast furnace slag when Na ₂ CO ₃ is used.
9 is a graph showing the relationship between the molten iron temperature and the slag fluidity when Na ₂ CO ₃ is used.

Hereinafter, embodiments of a blast furnace operation method and a blast furnace operation apparatus according to the present invention will be described with reference to the accompanying drawings.

The blast furnace operation method of the present invention blows a flowability improving material, which can lower the viscosity of the slag and increase the fluidity, into the blast furnace so as to reduce the viscosity and the melting point of the slag.

That is, according to the present invention, when the content of the impurities containing the flowability improving material in the slag increases, the specific basicity (CaO / SiO ₂ or CaO + MgO / SiO ₂ + Al ₂ O ₃ ) and Al ₂ O ₃ , the inventors have focused on the phenomenon that the viscosity and melting point of the slag are lowered. The impurities containing the fluidity improving material lower the viscosity and melting point of the slag by performing a breaker to break the tetrahedral bond of SiO ₂ and Al ₂ O ₃ .

FIG. 2 is a chemical reaction diagram showing application of a calcium oxide and a sodium oxide as a fluidity improving material. The fluidity improving material is an alkali which can dissociate the slag structure by breaking the tetrahedral bond of SiO ₂ and Al ₂ O ₃ of the slag. (Hereinafter, referred to as an " alkaline-based element compound ") containing a group element (Na, K, etc.). At this time, the compound of the alkaline element should be introduced into the blast furnace in oxide form so as to break the tetrahedral bond of SiO ₂ and Al ₂ O ₃ .

In other words, oxygen takes away electrons from other atoms and oxidizes them. The alkali metal is located at the beginning of the left end period of the periodic table and is a highly reactive tender metal. Therefore, in an alkaline-based element compound, especially in an oxide-type compound, oxygen ions chemically react with SiO ₂ and Al ₂ O ₃ constituting the slag to break the bond, and Si ^{4 +} and SiO ₂ of Al ₂ O ₃ the four O ^-2 coupled to each vertex of a tetrahedron Al ^{3 +} is substituted with alkali elements. As a result, the structure of the slag present in the blast furnace can be dissociated, and the absolute amount of the slag itself can be reduced, and as a result, the flowability of the slag can be improved.

On the other hand, the fluidity improving material may include Na ₂ O, Na ₂ CO ₃ , Na ₂ CO ₄ , NaHCO ₃ , (NaPO ₃ ) ₆ in terms of recycling the wastes generated from steelworks to contribute to environmental pollution problems.

Referring to FIG. 2, when the calcium oxide in the slag that contains the Al ₂ O ₃ injected oxygen ions of Al ₂ O ₃ is dissociated is that each vertex of the tetrahedron substituted with calcium behavior as a pair (pair), and sodium-based When the oxide is added, each vertex of the tetrahedron is replaced with a sodium element and behaves as a single unit. That is, when the components contained in the slag are introduced to dissociate the structure of the slag, such as CaO, even if it is an oxide, the slag does not completely dissociate due to its behavior as a pair. However, when the alkaline- The slag structure can be completely dissociated into a single unit.

FIG. 3 is a graph showing changes in viscosity and melting point of slag upon addition of the flowability improving material, showing an example in which Na ₂ O is added as a flowability improving material.

The viscosity of the slag decreases gradually regardless of the basicity of the slag when the fluidity improving material is added, and the viscosity decrease of the slag is larger as the basicity is lower.

In addition, the addition of the fluidity improver reduces the melting point of the slag to a large extent, and in particular, the lower the melting point of the slag is, the lower the basicity is.

When the basicity exceeds 1.2, the slag melting point is significantly changed compared to the viscosity reducing effect depending on the fluidity improving material. Therefore, the present invention is preferably applied when the basicity is 0.8 to 1.2.

On the other hand, as a method of blowing the slag fluidity improving material into the blast furnace, a method of injecting fuel and raw material into the upper part of the blast furnace can be applied. In this case, the fluidity improving material can be transferred along the feeding route of the blast furnace according to the existing blast furnace operation. When the blast furnace is charged into the blast furnace, It is necessary to take a form of lump having a particle size of 45 mm.

However, in the case of fluctuating blast furnace slag, it takes a long time to lower the slag viscosity because it takes longer than 48 hours for the fluidity improving material put into the upper part of the blast furnace down to the tuyere, and the fluidity improving material is lowered, SiO ₂ ratio) is lowered, the viscosity of the slag is increased so much that it may accumulate in the furnace, which may flow back through the blast furnace tuyere.

As another method for blowing the fluidity improving material into the blast furnace, a method of directly blowing the flow improving material through a blast furnace can be applied.

When the fluidity improving material is directly blown through the blast furnace of the blast furnace, the time for reaching the slag from the time when the flowability improving material is blown into the blast furnace is remarkably saved, thereby reducing the viscosity and melting point of the slag in a short time (2 to 3 hours) It is preferable to add the flowability improving material to the upper part of the blast furnace.

In other words, when the fluidity improving material (Na, K) is blown through the blast furnace of the blast furnace, the blast furnace is operated directly at the position where the molten slag is present, .

On the other hand, in the lower part of the blast furnace, a plurality of tuyeres are formed in a circumferential direction at regular intervals. When the flow improving material is blown through the tuyere, the tuyere must be blown in uniformly or uniformly in all tuyere in the circumferential direction of the blast furnace. In other words, the fluidity improving material should be continuously supplied in a uniform amount or ratio in all the tongues in the circumferential direction of the blast furnace, so that the fluctuation factor of the blast furnace can be minimized.

The side effects that may occur when the fluidity improver is blown in through the blast furnace and when there is a variation in the flow rate in the circumferential direction is as follows.

First, the fluctuation of the heat flux ratio (the heat capacity of the charge / the heat capacity of the gas) may cause the instability of the softened welded joint due to the change of the theoretical flame temperature. That is, when the temperature distribution of the furnace changes due to the change of the heat flow ratio, the softened welded zone increases in the process of moving up and down the position of the softened welded zone where the aeration resistance is greatest in the furnace.

Second, there is a difference in the amount of pulverized coal burned at the tip of the tuyere when the flow rate variation of the fluidity improving material in the circumferential direction occurs, and the amount of fuel consumed at the tip of the tuyere is different, It can induce a feeling. When the feeling of comfort is intensified, the inclination of the first iron ore on the blast furnace is increased, making it difficult to charge the desired amount of iron ore and fuel. This is because the slope at the entrance to the facility will flow to an undesired location.

In addition, when the amount of pulverized coal and fuel consumed at the tip of the tuyere is changed, the amount of the heat that is introduced into the furnace and the amount of the generated high-temperature reducing gas varies depending on the circumferential direction, so that the upward force of the gas locally increases. It increases the risk that you can.

Therefore, when the fluidity improving material is introduced through the trough of the blast furnace, it is preferable that the fluidity improving material is formed in powder form so that the slag can be uniformly distributed over the entirety.

Hereinafter, a method of directly blowing the fluidity improving material into the blast furnace will be mainly described.

4 shows a blast furnace operation method and apparatus according to a first embodiment of the present invention.

Referring to Fig. 4, the blast furnace apparatus of the first embodiment comprises a fuel hopper 10 for supplying fuel, a fuel crusher 20 for crushing the fuel to a set particle or less, a storage hopper 40 A plurality of feed tanks 50 that are alternately supplied with the pulverized fuel from the storage hopper 40, a flow improver material supplier 60 that mixes the flow improver with the pulverized fuel, a mixed material of the pulverized fuel and the flow improver To the plurality of blast furnace tuyeres.

A cyclone 30 is installed between the fuel crusher 20 and the storage hopper 40 so as to collect dust generated when the fuel is crushed. .

A plurality of distributors 70 may be provided. In the first embodiment, the distributor 70 is divided into the first distributor and the second distributor, but the distributor 70 may be arranged in a larger number as required. That is, the fluidity improving material capable of reducing the slag melting point and viscosity can be directly blown into the tuyeres 1a of the blast furnace 1, and the first distributor and the second distributor The second distributor is alternately connected to a plurality of blast-furnace tuyeres through a plurality of distribution lines.

For example, a plurality of tuyeres may be divided into an odd number and an even number, and the odd tuyere may be connected to the first distributor through a distribution line, and the even tuyere may be connected to the second distributor through a distribution line. Accordingly, the first distributor and the second distributor may be alternately operated to blow the fluidity improving material into the blast furnace trough or the fluidity improving material may be blown into the blast furnace through the first distributor. If the abnormality occurs, the operation of the first distributor And the second distributor is operated to blow the fluidity improving material into the blast furnace tuyere.

A transfer gas supply unit 80 is provided between the feed tank 50 and the distributor 70 to feed the transfer gas for transferring the process material and the fluidity improving material supply unit 60 supplies the transfer gas supply unit 80 with fluidity And is configured to supply the improvement material.

An inert gas such as argon (Ar), helium (He), or nitrogen (N) may be used as the transfer gas to prevent the reaction with other materials in the blast furnace 1.

The blast furnace operation method using the blast furnace apparatus of the first embodiment thus constituted comprises a fuel supply step for supplying and supplying fuel in a fixed quantity, a fuel crushing step for crushing the fuel to a predetermined particle or less, a pulverized coal And a distribution step of distributing and supplying pulverized coal mixed with the fluidity improving material to a plurality of blast furnace tuyeres. In the transfer step, the flowability improving material is supplied to the pulverized coal to be mixed with the pulverized coal.

In the fuel crushing step, the fuel is crushed to a predetermined particle size or less, for example, 0.5 mm or less, and if it is less than the set particle size, it can contribute to stabilization of the blast furnace operation.

In the flow improving material supply step, 1 to 10 t / hr of flow improver may be supplied per 1 to 150 t / hr of the pulverized coal.

The distributing step may include at least two distributor alternately connected to the plurality of blast furnace tuyeres, and sequentially injecting the differential fuel into the blast furnace from each distributor.

In addition, the blast furnace operating method of the first embodiment may further include a transfer gas supplying step of supplying a transfer gas for transferring the fine coal and the flow improver to the blast furnace side.

At this time, inert gas selected from among Ar, He, and N is used as the transport gas. In the transport gas supply step, the transport gas is supplied at a pressure of 1 to 20 kg / cm 2.

FIG. 5 illustrates a blast furnace operation method and apparatus according to a second embodiment of the present invention.

Referring to Fig. 5, the blast furnace apparatus of the second embodiment is similar to that of the blast furnace apparatus of the first embodiment. However, in the blast furnace apparatus of the second embodiment, a plurality of pulverized coal feed tanks are provided so as to alternately supply pulverized coal between the storage hopper 40 and the distributor 70, and the fluidity improving material supplying unit 60 includes a plurality of pulverized coal feeders And to supply the fluidity improving material to the tank.

That is, in the second embodiment, a small-sized fluidity improving material feed tank is separately prepared as the fluidity improving material supply unit, and when the pulverized coal is introduced into the pulverized coal feed tank, a certain amount of the fluidity improving material is continuously taken in.

Since the blast furnace operation method applied to the second embodiment is similar to the blast furnace operating method of the first embodiment, a detailed description thereof will be omitted.

6 shows a blast furnace operation method and apparatus according to a third embodiment of the present invention.

Referring to FIG. 6, the blast furnace apparatus of the third embodiment comprises at least one fuel silo 5 for storing fuel, at least one flow improver material silo 6 for storing the flow improver material, And a fuel crusher 20 for crushing the fuel supplied from the fuel hopper 10 to a predetermined particle or less and supplying it to the blast furnace tuyere.

That is, the blast furnace operating apparatus of the third embodiment utilizes the pulverized coal silo blending function to fill the fluidity improving material silo with a material containing Na and K, So that they can be mixed evenly while crushing them simultaneously in the fuel crusher (20).

The blast furnace operation method using the blast furnace apparatus of the third embodiment configured as described above is characterized by including a fuel supply step of supplying and supplying fuel in a fixed quantity, a flow improvable material supply step of supplying the flow improvable material to be mixed with the supplied fuel, A fuel crushing step of crushing the fuel mixed with the material to a set particle or less, and a pulverizing coal input step of injecting pulverized pulverized fuel into the blast furnace.

7 to 9 are tables showing the relationship between the Al ₂ O ₃ content and the slag fluidity in the blast furnace slag and the relationship between the molten iron temperature and the slag fluidity length, respectively, when the flowability improving material was directly blown into the blast furnace slag according to the embodiment of the present invention, Graph.

According to this, when the slag fluidity improving material (powdery material containing Na and K) is directly blown through the interior of the blast furnace, in particular, through the trough of the blast furnace, the fluidity improving material acts directly on the slag, It can be deduced that the flow length of the slag is increased more than before and the viscosity of the slag is decreased by this. Accordingly, the slag viscosity can be lowered by 10 to 15% and the melting point can be lowered by 70 to 100 ° C within 2 to 3 hours after the fluidity improving material is blown.

That is, the slag viscosity and the melting point are remarkably lowered in a short time to smooth the discharge of the slag, and the flow path through which the gas inside the furnace can rise relatively can be widened, thereby reducing the ventilation resistance and facilitating the recovery of the sulfur content. If the furnace slag is not discharged to the outside of the furnace due to the aging irregularity, the amount of residual slag in the furnace is increased.

One; Blast furnace 1a; Tongue
5.6; Silos 10; Fuel hopper
20; Fuel crusher 30; Cyclone
40; Storage hopper 50; Feed tank
60; A fluidity improving material supply unit 70; Distributor
80; [0052]

Claims (21)

Discharging the fuel and the raw material in a quantitative manner and supplying the fuel and the raw material to the furnace side;
Crushing the supplied fuel to a set particle size or less;
Transferring the pulverized fission fuel to the blast furnace side;
Supplying the fluidity improving material to be mixed with the pulverized fuel;
Injecting the fluidity improving material mixed with the fluidity improving material into the blast furnace through a plurality of tuyeres provided in the blast furnace;
/ RTI >
Wherein the flow improver is made of an alkaline-based compound and is injected into the blast furnace in the form of an oxide powder.
The method according to claim 1,
Wherein the flowability improving material breaks the tetrahedral bond of SiO ₂ and Al ₂ O ₃ of the slag and is replaced with an alkali-based element.
delete delete delete The method according to claim 1,
Wherein the step of crushing the fuel comprises crushing the fuel to a size of 0.5 mm or less.
The method according to claim 1,
Wherein the step of supplying the fluidity improving material comprises supplying the fluidity improving material at 1 to 10 t / hr per 1 to 150 t / hr of the pulverized fuel to be conveyed.
The method according to claim 1,
Wherein the step of injecting the fluidity improving material mixed fluid into the blast furnace is performed by alternately connecting at least two or more distributors to the blast furnace blades, sequentially discharging the blended fluid containing the fluidity improving material from each distributor into the blast furnace In the blast furnace.
The method according to claim 1,
Further comprising the step of supplying the transfer gas to transfer the mixed fuel mixed with the flow improver to the blast furnace side.
10. The method of claim 9,
Wherein the transfer gas is any one of inert gas selected from Ar, He, and N gases.
11. The method of claim 10,
Wherein the transfer gas is supplied at a pressure of 1 to 20 kg / cm < 2 >.
The method according to claim 1,
Wherein the alkali-based compound is any one selected from Na2CO3, Na2CO4, NaHCO3 and (NaPO3) 6.
delete A fuel hopper for supplying fuel;
A fuel crusher for crushing the fuel supplied from the fuel hopper to a size smaller than a set particle size;
A storage hopper in which the pulverized pulverized fuel is stored;
A plurality of feed tanks for alternately receiving the differential fuel from the storage hopper;
A flow improvable material supply unit for mixing the flow improvable material with the pulverized fuel supplied to the plurality of feed tanks; And
A distributor for distributing the differentiated fuel mixed with the flowability improving material supplied from the plurality of feed tanks to a plurality of tuyeres provided in the blast furnace and blowing the mixed fuel into the blast furnace;
.
15. The method of claim 14,
Wherein the distributor is divided into a first distributor and a second distributor, and the first distributor and the second distributor are alternately connected to a plurality of blast-furnace tuyeres, respectively.
15. The method of claim 14,
Further comprising a transfer gas supply unit installed between the feed tanks and the distributor to supply the transfer gas for transferring the mixed fuel mixed with the fluidity improving material to the blast furnace side.
17. The method of claim 16,
Wherein the transfer gas is any one of inert gas selected from Ar, He and N gases.
delete delete 15. The method of claim 14,
And a cyclone is installed between the fuel crusher and the storage hopper.
One or more fuel silos and fluidity improving material silos, each storing fuel and flow improvers;
A fuel hopper supplied with fuel and fluidity improving material quantitatively discharged from the fuel silo and the flow improver material silos; And
A fuel crusher for crushing the fuel supplied from the fuel hopper to a size smaller than a set particle and mixing the pulverized fuel and the fluidity improving material;
.

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