JPS6164807A - Melt reduction method of iron ore - Google Patents

Abstract

PURPOSE:To eliminate the need for electric power for the heat source for melt reduction in a method for obtaining the preliminarily reduced matter of iron ore and char by bringing the iron ore, coal and O2-contg. gas into reaction in a fluidized bed by bringing the briquettes of such materials and coal into melt reduction reaction. CONSTITUTION:Iron ore 11 and limestone 12 are heated by the combustion heat of coal 13 and air 21 in an ore preheating furnace 1 and the limestone 12 is converted to quicklime 16 which is supplied to a fluidized bed reaction furnace 2. The coal 13 and O2-contg. gas 22 are blown thereto. The coal 13 is thermally decomposed to generate a reducing gas and is made to the char 15. On the other hand, the gas generated in a melt reduction furnace 4 or the reducing gas 33 obtd. by subjecting said gas to CO2 removal is heated and blown into the furnace 2 and is mixed with the formed reducing gas mentioned above to reduce the ore 11, thus forming the preliminarily reduced ore 14. The quicklime 16 desulfurizes the gas in the furnace 2 and is discharged together with the ore 14 and the char 15 from the furnace 2. A required quantity of the coal 13 is added thereto from the outside and is made into the brickettes 17 by mixing and lumping and thereafter the briquettes 17 are charged into the furnace 4. O2 22 is blown through a top blowing lance 5 and O2, coal, etc. are blown through bottom blowing tuyeres 6 by which the ore 14 is melt-reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for melting and reducing iron ore without using a blast furnace process.

(Prior Art) The most widely used process for obtaining molten iron by reducing iron ore is a method using a blast furnace.

In this blast furnace iron ore reduction process, a large amount of coke is used as a heat source and reducing agent. The coke supplied to the blast furnace is manufactured by carbonizing highly coking coal, as it needs to have enough physical strength to not be destroyed by the load of the contents of the furnace, which can reach tens of meters in height. However, the availability of strong coking coal is small worldwide, and the availability is unevenly distributed in different regions, so there is a problem that the supply tends to be unstable. In addition, it requires huge equipment (coke oven) and a great deal of labor to carbonize the coal.

Further, iron ore supplied to the blast furnace is usually sintered and charged into the blast furnace as sintered ore. However, the sintering process of iron ore requires a large amount of energy and
The process of obtaining sintered ore generates large amounts of sulfur oxides and nitrogen oxides, which require high costs to process.

Therefore, a simple iron ore reduction process that does not involve a blast furnace is strongly desired.

Various studies are underway to meet this demand.

For example, there is a method of reducing iron ore to metallic iron in a shaft furnace or rotary kiln and then melting this metallic iron in an electric furnace, but this method uses a large amount of electricity and power as a heat source for the melting pot of metallic iron. There is a drawback in terms of cost. In our country, electricity is the most expensive energy, and processes that use electricity as the main heat source are extremely disadvantageous.

Therefore, it is important to construct a process that uses cheap primary energy such as coal or coke as a heat source.

On the other hand, a smelting reduction process in which iron ore is reduced while being heated and melted has also been studied. In the melting and reduction process, the process depends on how to protect the refractory material in the furnace from the highly corrosive molten iron oxide, and how to supply the large amount of energy required for reduction and melting. This is the key to whether or not it can be realized.

For example, in one of the melt reduction processes,
There is a rotary furnace system disclosed in No.-13043. Although the rotary furnace method was proposed from the viewpoint of increasing thermal efficiency, it is difficult to increase its size due to the mechanical constraints of rotating the high-temperature reaction vessel.

Further, as one of the melting and reduction processes for metal oxides, there is a method that uses electric power as a heating source. For example, processes using arc furnaces or plasma.

Although these processes that use electricity as a heat source have the advantage of being able to perform heating in a reducing atmosphere, they have drawbacks in terms of cost and cost because they use electricity as a heat source.

On the other hand, in the melt reduction process that directly utilizes the heat of combustion of carbonaceous materials such as coal, it is difficult to achieve both the oxidation reaction of burning the carbonaceous materials and the reduction reaction of reducing metal oxides, such as iron ore. Yes, there has been no success story so far.

In recent years, with the progress of bottom-blowing converter technology, the analogy is
As disclosed in Publication No. 8085, by placing the fire point during combustion in a molten iron bath, it is possible to improve heat transfer efficiency and reduce erosion of refractories, thereby reducing the need for reduction, such as melting scrap. The possibility of realization has arisen in cases where processing is not required.

However, even with this converter technology, it has not yet been possible to charge metal oxides, such as iron ore, into a reaction vessel and perform melt reduction.

The technical issues in the process of melting and reducing metal oxides such as iron ore, which directly utilizes the heat of combustion of coal and other carbonaceous materials, are as follows: Second, how to charge the reducing agent into the smelting reduction furnace. Third, how to input heat into the smelting reduction furnace.

U.S. Patent No. 3985.544 discloses that in a fluidized bed, carbonaceous material is gasified through a partial combustion reaction with oxygen and turned into char, and iron ore is charged together with the carbonaceous material by the gas generated in this reaction. A process for reducing stones is disclosed. This U.S. Patent No. 3.985.544
In the process disclosed in the publication, iron ore pre-reduced by a reaction in a fluidized bed and char obtained by partial combustion of carbonaceous materials are loaded in powder form into an electric furnace through a nitrous arc electrode. The pre-reduced ore is dissolved and the reduction reaction proceeds using char as a reducing agent.

This prior art is excellent in that it can perform preliminary reduction of metal oxides such as iron ore and obtain the char necessary for melt reduction at the same time.

However, melting and reduction requires electricity as a heat source, and the process has not moved beyond the realm of electricity-based processes.

(Problems to be Solved by the Invention) This invention solves the problem that, when obtaining molten iron from iron ore, a process of carbonizing coal (coke manufacturing process) and a process of converting iron ore into burnt ore, such as in a blast furnace process, are required. The technical challenge is to create a process that does not require electricity as a heat source.

(Means for Solving the Problems) The gist of the present invention is to charge iron ore, coal, and oxygen-containing gas into a fluidized bed reactor and allow the reaction to proceed to produce a pre-reduced product of iron ore and char. and mix this pre-reduced ore with char and coal supplied from another system,
A method for melting and reducing iron ore, which comprises charging briquettes obtained by agglomeration into a top-bottom blowing converter type reaction vessel, and melting and reducing the pre-reduced ore.

The present invention will be explained in detail below.

In the process of this invention, pre-reduced ore produced in a fluidized bed reactor is melted and melted after reaching the interface between carbon-containing molten iron and slag in a smelting reduction furnace (top-bottom blown converter type reaction vessel). It is important to react.

Therefore, in this invention, a process of agglomerating the prereduced ore produced in the fluidized bed reactor together with char and other carbon materials is essential.

That is, the important point is how to bring the granular semi-reduced ore pre-reduced in the fluidized bed reactor to the reaction side with carbon in the iron bath. When trying to blow granular semi-reduced ore into the iron bath from the bottom blowing tuyere in order to reach the reaction side, the amount of granular semi-reduced ore per ton of molten iron produced is approximately 1.2~
13 tons of semi-reduced ore must be charged through the bottom blowing tuyere, which complicates the charging equipment. Therefore, the semi-reduced ore is not melted in the slag layer in the smelting reduction furnace.
It is necessary to form lumps of such a size that they reach the interface between the iron bath and slag, react with carbon in the iron bath, and proceed with reduction.

When agglomerating semi-reduced ore from a fluidized bed reactor, the present inventors mixed in charred coal that had been used for preliminary reduction of iron ore in the fluidized bed reactor, and added it to the smelting reduction furnace. We focused on incorporating a portion of the coal to be charged into briquettes, and at the same time making the coal itself function as a binder for agglomerating semi-reduced ore.

Furthermore, in the melting reduction furnace, carbonaceous material is suspended in the slag to promote the reduction reaction and reduce damage to the refractories.

Unlike the conventional technology using an electric furnace, as in the present invention, the heat source for the smelting reduction furnace is the combustion of carbonaceous materials and gas generated in the furnace, so that the slag on the iron bath is not exposed to an oxidizing atmosphere. However, in the present invention, this problem is solved by suspending carbonaceous material in the slag.

In the present invention, iron ore pre-reduced in a fluidized bed reactor is
The char obtained at the same time and the carbon material supplied from another system are agglomerated and charged into a smelting reduction furnace. After this agglomerate is charged into the furnace, it does not melt immediately, but passes through the slag layer and melts when it reaches the interface between the molten iron and slag, where the carbon in the molten iron converts it into iron ore. of the pre-reduced product is reduced. Therefore, even when the supply rate of pre-reduced ore (iron oxide) is high, the FeO concentration in the slag can be kept low, and damage to the refractories in the smelting reduction furnace can be maintained at a low level while maintaining high productivity. It became possible to melt and reduce the

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the drawings showing an apparatus for carrying out the invention.

In Fig. 1, 1 is an ore preheating furnace, and 2 is a fluidized bed reactor, which pre-reduces granular iron ore and separates the volatile content of granular coal charged at the same time. It functions to make the world a better place.

3 is an agglomeration device to which, for example, a briquette machine is applied, and mixes and agglomerates the pre-reduced ore from the fluidized bed reactor, char, and carbon material supplied from other systems.

4 is a melting reduction furnace, and in this invention, a top-bottom blown converter type reaction vessel is applied. The melting reduction furnace 4 includes a lance 5 for top-blowing oxygen, a tuyere 6 for bottom-blowing oxygen and, if necessary, a gas for stirring powdered carbonaceous material, an iron bath, and slag, and a lance 5 for blowing agglomerated materials (briquettes). 17) is provided with a charging device 7 for charging a solid charge such as 17) into the smelting reduction furnace.

(Operation) Next, the operation when melting and reducing iron ore using the apparatus shown in FIG. 1 will be explained.

Iron ore 11 and limestone 12 are heated in ore preheating furnace 1 by the heat of combustion reaction between coal 13 and air 21, and limestone (CaC03) is turned into quicklime (CaO) and supplied to fluidized bed reactor IK.

Note that lime-containing minerals such as dolomite can also be used instead of limestone. Especially in the melting reduction furnace described below,
When using a magnesia-based furnace material, magnesia-containing minerals such as dolomite are reasonable.

In the fluidized bed reactor 2, the stone L13 and oxygen or oxygen-containing gas 22 are blown into the preheated ore and quicklime in a fluidized state.

Then, the injected coal 13 is thermally decomposed (by heat exchange with the preheated ore and partial combustion due to reaction with oxygen), generates reducing gas, and becomes char 15.

From the viewpoint of preventing sintering troubles in the fluidized bed reactor (pre-reduction furnace), the amount of char produced is appropriate at 5 to 10%, but when using char as the heat source of the smelting reduction furnace, it should be increased to about 6096. You can also do that.6
An amount of char produced in excess of 0% is undesirable because it increases the heat load in the fluidized bed reactor.

On the other hand, in the fluidized bed reactor 2, the gas generated in the smelting reduction furnace 4 or the reducing gas 23 obtained by decarbonating this gas is exchanged with the fuel gas 24 from the fluidized bed reactor 2. The temperature is raised to 700-9001: and then blown in.

The reducing gas 23 blown into the fluidized bed reactor 2 is the coal 13
The mixture is mixed with the reducing gas produced by the thermal decomposition of iron ore to reduce the high temperature granular iron ore in a fluidized state, producing pre-reduced ore (
Semi-reduced ore) 14 is produced.

The preliminary reduction rate of iron ore is selected in the range of 0.5 to 0.8, which is advantageous for the reaction efficiency in the fluidized bed reactor (pre-reduction furnace) and the fuel utilization rate of the entire smelting reduction system of the present invention. Preferably, it is in the range of 0.6 to 0.7.

In addition, the quicklime 16 generated in the ore preheating furnace 1 is charged into the fluidized bed reactor 2 together with the preheated ore, and after desulfurizing the gas in the fluidized bed reactor 2, the semi-reduced ore 14 and char 15 It is also discharged from the fluidized bed reduction furnace 2.

The amount of quicklime is determined by the slag basicity (Ca o / Si 02
) is determined from 1.1 to 1.7 in consideration of the gangue components and amounts in the iron ore and carbonaceous material.

Thus obtained semi-reduced ore 14, char 15
The quicklime 16 is mixed with carbonaceous materials from outside the system such as coal and coke necessary for heat calculation in the smelting reduction furnace 4, and is kneaded and then molded by an agglomeration device 3, for example, a briquette machine, to form briquettes 17. , charging device 7
is charged into the melting reduction furnace 4.

In the melting reduction furnace 4, oxygen 22 is blown toward the bath from the top blowing lance 5, and oxygen and carbonaceous material such as coal are blown into the bath from the bottom blowing tuyere 6. Then, the carbon material contained in the supplied briquettes 17, the carbon material blown in with oxygen from the bottom blowing tuyere 6, or the carbon material such as coke 18 supplied from the charging device 7, and the top blowing lance 5. A large amount of heat is generated by reaction with oxygen supplied from

Due to this large amount of heat, the semi-reduced ore 1 in the briquette 17
4 melts, reduction progresses, and the molten iron 19 becomes '-'.

On the other hand, the gangue, carbonaceous material and quicklime 16 in the semi-reduced ore 14
The slag 20 is generated by the reaction, and is stored in the melting reduction furnace 4. Since the slag 20 thus increases in the melting reduction furnace 4 over time, it is discharged out of the furnace intermittently or continuously.

This invention agglomerates the pre-reduction process product in the fluidized bed reactor 2 and melts and reacts it preferentially at or near the interface between the molten iron 19 and the slag 20 in the smelting reduction furnace 4. This method is characterized by achieving a production rate as high as possible, and also by allowing both the oxidation reaction of the carbonaceous material and the reduction reaction of the semi-reduced ore 14 to proceed.This point will be further explained.

The present inventors, as described below in the section of the embodiments of the present invention,
When melting and reducing iron oxide in a melting furnace containing molten iron containing carbon and slag with coke suspended above it, iron oxide is used as a form of supply of iron oxide to the melting reduction furnace. It was found that the reduction rate was higher when the iron oxide was supplied in an agglomerated state rather than in the form of a granular powder.As a result of research involving experiments, it was found that the iron oxide in the form of lumps supplied from the upper part of the slag in the smelting reduction furnace without dissolving into slag.
It was found that the slag and molten iron had reached the interface.

There are usually two cases in which the reduction reaction of molten iron oxide with carbon occurs.

FeOx +XC5olid = Fe +xco--
=・(1) FeOx +XC1ron = Fe +
Equation 2) shows the reduction of iron oxide (FeOx) by carbon contained in molten iron.

FIG. 2 shows the progress of reduction of molten iron oxide by solid carbon and carbon in molten iron.

In Figure 2, curve A shows the progress of reduction of iron oxide by graphite and solid carbon forming the crucible, and curve B shows the progress of reduction of iron oxide by carbon-saturated molten iron. From Figure 2, the reduction reaction of iron oxide with solid carbon (curve A
), the initial reduction rate is very slow compared to the reduction reaction of iron oxide by carbon-saturated molten iron (curve B), and after a certain amount of time, iron oxide is reduced to form molten iron. , it can be seen that the reduction rate becomes faster as it approaches the state of curve B where reduction by carbon-saturated molten iron progresses.

In this way, the melting reduction rate of iron oxide is often due to the carbon in the molten iron, so in order to improve the productivity of the reactor, it is advantageous to have a process in which iron oxide and molten iron containing carbon are brought into direct contact. It is clear that

On the other hand, when reduced iron pellets are fed into molten slag and melted, since the temperature of the pellets is low, a solidified film of slag is formed on the surface, and after a certain amount of time, the slag solidifies. After the film has redissolved, the pellet itself begins to dissolve.

Figure 3 shows the change over time in the thickness of the coagulated slag film when a reduced pellet with a diameter of approximately 20 mm is immersed in molten slag at 1400°C. In the case of Figure 3, the coagulated film of slag on the pellet surface It can be seen that it takes about 3 minutes for the pellet to disappear and for the pellet to start dissolving.

In the iron ore melting reduction process of this invention,
9200 to 800 kg of slag is generated per ton of molten iron produced, and this slag is mainly Si02-At203.
- Consists of CaO.

Generally, the reaction rate of slag components is proportional to the concentration of the components involved in the reaction.

When the iron ore supplied to the smelting reduction furnace is dissolved into slag, the iron content is diluted into the slag, which is disadvantageous in terms of reaction rate.

The present invention takes advantage of the fact that the smaller the specific surface area of iron ore agglomerated with char etc., the longer the time delay when it dissolves into slag. The slag reaches the interface of the molten iron without being dissolved in the iron bath, where it comes into contact with the iron bath and dissolves and reacts, achieving the high reaction rate shown in Figure 2.

To create this condition, the agglomerated charge must be
It is necessary to control the sedimentation property in the slag in the smelting reduction furnace and the start time of dissolution into the slag. Therefore, semi-reduced ore14. When agglomerating Char 151 Coal 13, conditions must be determined with the following points in mind.

In order for the agglomerated materials (referred to as briquettes for simplicity) thrown into the slag being stirred by gas blowing from the bottom blowing tuyere 6 to settle without floating in the slag, it is necessary to It must have specific gravity. The lower limit of the size of the briquettes 17 is regulated from the viewpoints of reducing the specific surface area of the briquettes 17 and controlling the rate of dissolution of the precipitate, which has formed a solidified slag film due to the temperature difference with the molten slag, into the slag 20.

Furthermore, since the reduction rate of iron oxide is more advantageous in the molten state, increasing the briquette size too much is disadvantageous because it lengthens the melting time. Therefore, an upper limit is defined from this aspect.

These conditions regarding the briquette size are related to heating properties such as heat capacity and thermal conductivity, and are therefore also influenced by the ingredients and packing density of the briquette.

On the other hand, the conditions on the slag side in the smelting reduction furnace are as follows:
First, there are the physical properties related to heat transfer properties such as temperature and other slag melting points and heat capacity, and more important factors include the thickness of the slag layer, the apparent density that decreases due to bubbles generated during the reaction process, and other important factors. There are factors related to the settling properties of briquettes, such as the strength of stirring.

As described above, it is difficult to generalize the conditions for allowing the briquettes to reach the slag-metal interface without melting in the smelting reduction furnace. The briquette size is determined based on the production rate of molten iron, the required amount of gas to be generated from the smelting reduction furnace, the preliminary reduction rate of iron ore determined from the heat balance in the fluidized bed reactor, and the required amount of carbon material. Determine the composition (amount of iron ore, amount of carbonaceous material, amount of quicklime), and further consider the amount of bottom-blown oxygen, the stirring intensity determined by the amount of stirring gas, and the thickness of the slag layer.

As a guideline for the briquette size, the terminal velocity equation of particles in a fluid by Stokes μ5 Viscosity of varnish slag Ckf/m ” sec] um: Speed of stirred slag Cm/sec) pg = Density of briquette Cky/m 3) ρ3 : The apparent density of the slag during forming [k = 7 m3]D, and the limit size of briquettes that flow equally with varnish slag (m) determine the size of briquettes that flow equally with slag, so a particle size larger than this is determined. Bye.

According to the experience of the present inventors, a briquette size of 10 to 50 tmn in diameter gave good results.

In actual operations, some of the iron ore is dissolved into slag,
In particular, when the charging speed of briquettes into the smelting reduction furnace is high, the FeO concentration in the slag becomes high. In such a case, coke or char produced in a fluidized bed reactor is suspended in slag, and reduction with solid carbon proceeds in parallel to lower the FeO concentration.

On the other hand, carbon may be supplied to the iron bath by charging carbon material from the top, but an effective method is to blow it into the iron bath along with oxygen from the bottom blowing tuyere.

FIG. 4 shows the carbon dissolution rate versus the coke injection rate when coke is blown into the iron bath from the bottom blowing tuyere. As is clear from this figure, sufficient carbon can be supplied by blowing coke from the bottom blowing tuyere.

(Example) Iron oxide powder, iron oxide pellets, semi-reduced ore, char, and quicklime obtained from the fluidized bed reactor shown in Fig. 1 were agglomerated using a high frequency melting furnace with a rated amount of molten metal of 100 i < 9. The three types of raw materials for the briquettes obtained by this process were each melted and reduced.

In melt reduction using iron oxide powder (iron ore powder) as a raw material, 60 kf of carbon-saturated iron is melted in the aforementioned high-frequency melting furnace,
While blowing oxygen into the iron bath from the bottom tuyere, Cab:
45%, 5102m 85%, klzo3: 1
Melting reduction was carried out in the presence of a slag consisting of 0'76°MgO:10%. The thickness of the slag layer when standing still is 4
It was 0rm+. Coke grains (particle size: 10
mm), and when the temperature reached 1500°C, iron ore (particle size: 0.075 to 2 wR) was added so that the iron concentration in the slag was 10 parts.

Slag was sampled at predetermined time intervals while maintaining a constant temperature, and iron was analyzed to investigate the decrease in iron concentration in the slag as reduction progressed, thereby determining the reaction rate.

In FIG. 5, the reaction rate constants are shown as a function of the amount of coke present in the slag.

Figure 5 shows that the reduction rate increases as the amount of coke increases, and that the reaction proceeds at a considerable rate even when the amount of coke is zero, and that the reduction reaction is carried out by the carbon in the iron bath. I understand that.

The reaction rate when iron oxide (iron ore powder) pellets are used as a raw material in melt reduction is also shown in broken lines in FIG.

As is clear from FIG. 5, when iron oxide pellets are used as the raw material for melt reduction, the reaction rate is much higher than when iron oxide powder is used as the raw material.

As mentioned above, when iron oxide pellets are used as a raw material, the pellets dissolve near the interface between the iron bath and the slag due to the difference in sedimentation and dissolution rate with respect to slag, and this area locally contains iron oxide. This is because the part with high concentration υ is advantageous for the reduction reaction. Furthermore, since the above-mentioned areas with high iron oxide concentrations were localized, there was no adverse effect on the furnace wall strength.

Next, semi-reduced ore, char (mixing ratio 10% by weight), quicklime, and coal obtained from the fluidized bed reactor shown in Figure 1 were kneaded and agglomerated at high temperature, and this was used as the raw material for smelting reduction. The relationship between the reaction rate constant and the amount of coke in the slag is also shown as point A in FIG.

It can be seen that the reducing property is further improved due to the reaction accelerating effect of incorporating carbonaceous material into the raw material briquettes.

In the process of the present invention, semi-reduced ore and charcoal obtained from a fluidized bed reactor are mixed at a high temperature of 700 to 800°C, so a substance that exhibits fluidity at high temperatures, such as coal, is mixed as a binder and heated. It is possible to agglomerate, in which case there is no need to add a binder separately,
Not only is it advantageous in terms of cost, but it is also excellent in terms of energy use efficiency from the perspective of utilizing the sensible heat of semi-reduced ore.

In this example, when agglomerating the raw materials, the mixing ratio of char is 10% by weight, but in order to ensure reaction and dissolution in the melting reduction furnace, for example, char having a volatile component of about 30% is required. In seeds, an additional 500 kf
Some coal is required as a reducing agent and heat source.

In a smelting reduction furnace, if powdered coal is fed from the top, it will scatter due to the gas generated in the furnace, making it extremely difficult to charge it into the furnace, but it can be obtained from a fluidized bed reactor. Charging becomes extremely easy if it is agglomerated together with semi-reduced ore and char and charged as briquettes.

When agglomerating the raw material charged to the smelting reduction furnace, the amount of char was set at 10% by weight from the viewpoint of preventing sintering in the fluidized bed reactor and other reasons, but from the point of view of heat balance in the smelting reduction furnace, An increase in the amount of char leads to a decrease in the amount of coal required, and since char is advantageous in terms of reaction, it is better to increase the amount of char within the range allowed by the moldability of briquettes and the cost of char-forming.

(Effects of the Invention) Since the present invention is constructed and operated as described above, the present invention can be used in the carbonization process of coal used in coke production, the process of sintering iron ore, and furthermore, does not require electric power for heating. It is possible to produce molten iron from iron ore and coal using extremely compact equipment with high equipment and labor productivity without having to do so.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing the overall image of the melting reduction method of the present invention,
Figure 2 shows the transition of melting and reduction of iron oxide by solid carbon and carbon in molten iron, Figure 3 shows the change over time in the thickness of slag solidified and adhered to the surface of pellets immersed in molten slag, and Figure 4 The figure shows the relationship between the dissolution rate of carbon in molten iron and the coke injection rate when coke is bottom blown, and Figure 5 shows the form of iron ore supplied to the smelting reduction furnace in the form of powder, pellets, and briquettes with carbonaceous material. It is a figure which shows the change of the reduction rate when changing. 1... Ore preheating furnace 2... Fluidized bed reactor 3...
・Agglomeration device 4... Melting reduction furnace (top-bottom blowing converter type reaction vessel) 5...
Top blowing lance 6...Bottom blowing lower...Charging device
11... Iron ore 12... Limestone 13.
... Coal 14 ... Preliminary reduced ore (semi-reduced ore) 15.
... Char 16 ... Quicklime 17 ... Agglomerated material (briquettes) 18 ... Coke 19 ... Molten iron 20 ...
Slag 21...Air 22...Oxygen-containing gas 23...Reducing gas 24...Fuel gas - 1/1 inch (J, /e-"...
-)尤4(suC Ajo-eup 1(2to^)

Claims (1)

[Claims] Iron ore, coal, and oxygen-containing gas are charged into a fluidized bed reactor and the reaction proceeds to obtain a pre-reduced product of iron ore and char, and this pre-reduced ore and char as well as coal supplied from another system. A method for melting and reducing iron ore, characterized in that briquettes obtained by mixing and agglomerating iron ore are charged into a top-bottom blowing converter type reaction vessel, and the pre-reduced ore is melted and reduced.