JP5867428B2 - Hot metal manufacturing method using vertical melting furnace - Google Patents

Description

  The present invention relates to a method for producing hot metal by using a vertical melting furnace, melting an iron source mainly composed of iron-based scrap using coke as a main heat source.

In vertical melting furnaces for iron making such as cupolas and shaft furnaces, materials that act as heat sources such as iron sources and coke are charged from the top of the furnace, and air or oxygen-enriched air is blown from the bottom of the furnace at room temperature or high temperature. Yes. Hot metal is produced by applying heat generated by the combustion of coke or the like to an iron source and melting it.
For example, in a vertical melting furnace in a foundry, pig iron purchased from the outside or pig iron scrap generated at its own site is used as an iron source. On the other hand, there are also vertical melting furnaces that produce pig iron mainly from iron-based scrap. Here, for convenience, the former is called a cupola and the latter is called a shaft furnace.
In cupolas and shaft furnaces, the iron source used is mainly different, but it is common to dissolve the iron source using the combustion heat of coke.

As a heat source or a reducing material, coke is generally used, but pulverized coal or waste plastic is also blown in as an auxiliary air accompanied by blowing.
In addition, as part of the iron source, massive iron ore mainly composed of iron oxide, so-called sintered ore obtained by sintering powdered iron ore, pellets obtained by granulating powdered iron ore, and generated in steel mills A dust agglomerate obtained by agglomerating dust containing iron may be charged from the top of the furnace. The reason for the agglomeration of dust is that in vertical melting furnaces, there is a gas flow from the bottom of the furnace to the top of the furnace. This is because it is discharged outside the furnace and hot metal cannot be obtained.
After being charged from the top of the furnace, the iron oxide, which is the iron source, descends to the high temperature region below the furnace with time, and comes into contact with reducing gas (CO gas) or coke, leading to a reduction / melting reaction. It is possible to obtain hot metal (molten pig iron).

Coke used as a heat source contains about 8 to 13 mass% of ash, and elements other than iron are also contained in the iron source, and these are so-called slag (slag) and molten iron along with hot metal. It needs to be discharged from the furnace. Substances other than iron, such as ash, generally have a high melting point and are difficult to discharge from a vertical melting furnace as they are, so add a fossilizing agent such as limestone or silica (additional raw material for adjusting slag components) to lower the melting point. It is widely done.
On the other hand, coke reacts with oxygen in the blast and burns to generate carbon dioxide (CO ₂ ) and heat (the following formula (1)). The generated CO ₂ gasifies coke to carbon monoxide (CO), and this reaction is an endothermic reaction (formula (2) below). Therefore, if the endothermic reaction can be suppressed, the coke ratio can be reduced. If the amount of expensive coke used can be reduced, the hot metal production cost can be reduced (the following formulas (1) and (2) are based on Non-Patent Document 1).
C + O ₂ = CO ₂ (ΔH ⁰ ₂₉₈ = -393.5 kJ / mol: exotherm) (1)
C + CO ₂ = 2CO (ΔH ⁰ ₂₉₈ = 172.4kJ / mol: endotherm) (2)

It can be easily understood that the contact of carbon (coke) and CO ₂ gas may be cut off in order to suppress the reaction of the formula (2). For this reason, Patent Document 1 proposes a method of suppressing the reaction of the fuel / reducing material by coating the surface of coke with a substance that suppresses the reaction such as mud or powder. In Patent Document 1, as a substance that suppresses the reaction, lime, a magnesia-based basic substance, an alumina-based neutral inorganic substance, an acidic inorganic substance such as quartzite, a powder mainly composed of an iron alloy powder such as FeSi, There is a slurry of these powders dissolved in a liquid.

JP 2000-328079 A

The Japan Institute of Metals, Introduction to Metal Chemistry Series 2 Steel Smelting, Maruzen Co., Ltd., 2000, p.34

  However, the method of Patent Document 1 requires the cost of finely pulverizing the coating material to coat the surface of the coke, and also includes a water tank for dissolving the coating material in water, a spraying device for the coating material on coke, and the like. This requires a lot of money. Therefore, although the method of patent document 1 has a fixed effect, it can be said that it is a method which is difficult to implement practically.

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, and from the top of the vertical melting furnace, as a raw fuel, an iron source mainly composed of iron-based scrap, coke, and a fouling agent are charged. However, in the method of producing hot metal by melting the iron source mainly by the combustion heat of coke, the coke gasification can be effectively suppressed and the amount of coke used can be reduced. It is providing the hot metal manufacturing method which can be implemented at low cost without performing.

As a result of repeated experiments and studies to solve the above-mentioned problems, the present inventors have compared the distribution state of raw fuel, particularly CaO, in the raw fuel layer formed by one charge of raw fuel from the top of the furnace. It was found that coke gasification can be effectively suppressed only by optimizing the relationship between the raw material layer and the coke layer. Furthermore, it has been found that coke gasification can be more effectively suppressed by optimizing the relationship between the raw material layer having a high SiO ₂ content and the coke layer.

The present invention has been made on the basis of such knowledge and has the following gist.
[1] From the top of the vertical melting furnace, an iron source mainly composed of iron-based scrap, coke and iron making agent are charged as raw fuel, and the iron source is mainly melted by the heat of combustion of the coke and molten iron. A method of manufacturing
The raw fuel layer formed by charging the raw fuel for one time from the top of the furnace is at least an iron-based scrap layer (s), a coke layer (c), and a raw material layer made of a raw material having a CaO content of 5 mass% or more ( x), and a raw material layer (y) made of a raw material having a SiO ₂ content of 95 mass% or more, and each layer is formed in any of the following forms (i) to (iv), and in this form, CaO A method for producing hot metal using a vertical melting furnace, wherein a raw material layer (x) made of a raw material having a content of 5 mass% or more is formed in contact with a coke layer (c).
(I) An iron-based scrap layer (s) is formed in the lowermost layer, a coke layer (c) is formed in the periphery of the furnace wall of the upper layer, and a raw material layer (x) is formed in the center of the furnace, and the coke layer (c The raw material layer (y) is formed on the upper layer.
(Ii) An iron-based scrap layer (s) is formed in the lowest layer, a coke layer (c) around the upper wall of the furnace wall, a raw material layer (x) on the lower side of the furnace center, and the upper side of the furnace center The raw material layer (y) is formed respectively.
(Iii) An iron-based scrap layer (s) is formed in the lowermost layer, a coke layer (c) is formed in the upper layer, a raw material layer (y) is formed around the upper furnace wall, and a raw material layer ( x) is formed respectively.
(Iv) An iron-based scrap layer (s) is formed in the lowest layer, a coke layer (c) around the upper furnace wall, a raw material layer (y) on the lower side of the furnace center, and an upper side of the furnace center The raw material layer (x) is formed respectively.

[2] In the production method of [1] above, in the raw fuel layer formed by charging the raw fuel once from the top of the furnace, the raw material layer (y) made of a raw material having a SiO ₂ content of 95 mass% or more is provided. A method for producing hot metal using a vertical melting furnace, wherein the hot metal is formed in contact with the coke layer (c).
[3] In the production method of [1] or [2] above, the raw material having a CaO content of 5 mass% or more is at least in an agglomerated product of a CaO-based fossilizing agent, iron-containing dust and / or iron-containing sludge. A method for producing hot metal using a vertical melting furnace, wherein the hot metal melting furnace is at least one selected from the group consisting of:

[4] In the manufacturing method according to any one of [1] to [3] , raw fuel is charged into a bucket having a gate that can be opened at the bottom, and the raw fuel layer in the bucket is at least iron-based. scrap layer (s _0), coke layer (c _0), the raw material layer CaO content is from 5 mass% or more ingredients (x _0), and the raw material layer SiO ₂ content is from 95 mass% or more ingredients (y ₀ And each layer is formed in any of the following forms (a) to (d),
(A) An iron-based scrap layer (s ₀ ) is formed in the lowermost layer, a coke layer (c ₀ ) is formed around the inner wall of the upper bucket bucket, and a raw material layer (x ₀ ) is formed in the middle of the bucket. A raw material layer (y ₀ ) is formed on the layer (c ₀ ).
(A) An iron-based scrap layer (s ₀ ) is formed in the lowest layer, a coke layer (c ₀ ) around the inner wall of the bucket upper layer, a raw material layer (x ₀ ) at the lower side of the bucket center, and the bucket center A raw material layer (y ₀ ) is formed on the upper side of each.
(C) An iron-based scrap layer (s ₀ ) is formed in the lowermost layer, a coke layer (c ₀ ) is formed in the upper layer, a raw material layer (y ₀ ) around the inner wall of the upper bucket, and a central portion of the bucket A raw material layer (x ₀ ) is formed.
(D) An iron-based scrap layer (s ₀ ) is formed in the lowermost layer, a coke layer (c ₀ ) around the inner wall of the upper bucket bucket, a raw material layer (y ₀ ) at the lower side of the bucket center, and the bucket center A raw material layer (x ₀ ) is formed on the upper side of each.
A method for producing hot metal using a vertical melting furnace, wherein the raw fuel in the bucket is charged into the furnace by opening the gate at the bottom of the bucket at the top of the furnace.

[5] In the manufacturing method according to any one of [1] to [3] , raw fuel is charged into a bucket having a gate that can be opened at the bottom, and the raw fuel layer in the bucket is at least iron-based. A scrap layer (s ₀ ), a coke layer (c ₀ ), and a raw material layer (x ₀ ) made of a raw material having a CaO content of 5 mass% or more are formed, and each layer is in the form of the following (1) or (2) To be formed and
(1) An iron-based scrap layer (s ₀ ) is formed at the lowermost layer, a coke layer (c ₀ ) is formed around the inner wall of the upper bucket bucket, and a raw material layer (x ₀ ) is formed at the center of the bucket.
(2) An iron-based scrap layer (s ₀ ) is formed in the lowermost layer, a coke layer (c ₀ ) is formed in the upper layer, and a raw material layer (x ₀ ) is formed in the central portion of the upper bucket.
By opening the gate at the bottom of the bucket at the top of the furnace, the raw fuel in the bucket is charged into the furnace, and then a raw material having a SiO ₂ content of 95 mass% or more is charged from the charging chute provided at the top of the furnace. In the raw fuel layer formed by charging the raw fuel from the top of the furnace by being charged into the inside, each layer is formed in the form of (i) or (iii) A method for producing hot metal using a melting furnace.

  According to the present invention, an iron source mainly composed of iron-based scrap, coke, and a coking agent are charged as raw fuel from the top of the vertical melting furnace, and the iron source is mainly melted by the combustion heat of the coke. Thus, in the method for producing hot metal, since the gasification reaction of coke, which is an endothermic reaction, is effectively suppressed, the gas utilization rate can be increased and the amount of coke used can be reduced. Moreover, since the method of the present invention can be carried out at low cost without subjecting the coke to a special treatment, it is possible to produce hot metal at a low cost in combination with the reduction in the amount of coke used.

The graph which shows the test result which investigated the coke gasification rate about the case where the material packed bed is coke alone and the case where it is a mixture of coke and other materials. Explanatory drawing showing the test equipment used to quantify the coke gasification rate Schematic diagram showing the state of coke gasification reaction in the material packed bed CaO content in the raw material in contact with the coke, graph SiO ₂ content indicating the effect on the gasification reaction rate of the coke Explanatory drawing which shows one Embodiment of the vertical melting furnace provided for implementation of this invention, and the charging method of the raw fuel with respect to this vertical melting furnace Explanatory drawing which shows the distribution state (charging state) of the raw fuel layer in the furnace in the present invention method When the raw fuel put in the bucket is charged into the furnace, the distribution state (charging state) of the raw fuel layer in the bucket for obtaining the distribution state (charging state) shown in FIG. ) Explanatory drawing which shows the charging procedure of the raw fuel in the bucket for obtaining the distribution state (charging state) of the raw fuel layer in the bucket shown in FIG. Explanatory drawing which shows the charging procedure of the raw fuel in the bucket for obtaining the distribution state (charging state) of the raw fuel layer in the bucket shown in FIG. Explanatory drawing which shows the charging procedure of the raw fuel in the bucket for obtaining the distribution state (charging state) of the raw fuel layer in the bucket shown in FIG. Explanatory drawing which shows the charging procedure of the raw fuel in the bucket for obtaining the distribution state (charging state) of the raw fuel layer in the bucket shown in FIG. 1 shows a charging guide for charging raw fuel around the inner wall of the bucket. FIG. (A) is a plan view and FIG. (B) is a side view. The charging guide for charging the raw fuel into the central portion of the bucket is shown. FIG. (A) is a plan view and FIG. (B) is a side view. Explanatory drawing which shows the distribution state (charging state) of the raw fuel layer in the bucket in the conventional method when charging the raw fuel put in the bucket into the furnace Explanatory drawing which shows the charging procedure of the raw fuel in the bucket in the conventional method Explanatory drawing which shows other embodiment of the vertical melting furnace provided to implementation of this invention, and the charging method of the raw fuel with respect to this vertical melting furnace Explanatory drawing which shows the raw fuel layer formed in the furnace by charging raw fuel with the method of FIG.

The present inventors investigated the reactivity of coke with CO ₂ using the test furnace shown in FIG. A crucible was placed inside the vertical annular tube furnace, and coke and auxiliary materials or dust agglomerates were mixed and filled in the crucible. Limestone or silica was used as an auxiliary material. The dust agglomerated material is formed and solidified into a lump with cement so that the iron-containing dust generated in the steelworks can be recycled by reduction and melting in a vertical melting furnace. When fine dust is charged into a vertical melting furnace as it is, the air permeability is deteriorated and the air necessary for the combustion of coke cannot be sent. Usually, the particle size is agglomerated to a size of about 10 to 100 mm. used.

The reaction temperature was measured with a thermocouple inserted from above. In order to achieve a uniform distribution of the gas to the material packed bed (packed bed of mixture of coke and auxiliary materials or dust agglomerates), the lower part of the material packed bed was filled with alumina spheres. A mixed gas of CO ₂ and N ₂ was introduced into the furnace from the lower part of the apparatus through this filling part, and the change in mass was measured with an upper pan balance.
50 g of coke having a particle size of about 20 mm was used, and in the case of a gasification test using coke alone, only the coke was filled in the crucible. In the case of a gasification test of a mixture of coke and limestone or silica, and a gasification test of a mixture of coke and dust agglomerate, the particle size and filling amount of the coke are the same as above, and limestone, silica stone, and dust agglomerate. Was adjusted to the same particle size as coke. About 10 g of limestone, silica, or dust agglomerated material was uniformly mixed with coke.

As test conditions, the temperature was 1300 ° C., which is a standard condition in a vertical melting furnace, and the atmosphere was a mixed gas of 35 vol% CO ₂ and the remaining N ₂ . When the reaction of the above formula (2) occurs, carbon is gasified and its mass decreases. Therefore, the mass reduction rate per unit volume of the material packed bed was calculated and used as the gasification reaction rate.
In the case of coke alone, when coke and limestone are mixed, each test result when coke and silica stone are mixed is shown in FIG. In FIG. 1, the gasification reaction rate in the case of coke alone is set to “1.0”, and the gasification reaction rate of coke under the mixing conditions with the auxiliary raw materials (silica stone, limestone) is shown as an index. In this test result, when coke and silica were mixed, the gasification rate was slightly slow, and when coke and limestone were mixed, the gasification reaction rate was increased.
Table 1 shows the composition of the auxiliary raw materials (limestone and silica) used in the test, and the composition of dust (A, B) and Portland cement constituting the dust agglomerate, together with the ash composition of coke. The main component of silica is SiO ₂ , but the main component of limestone is CaO, and the main components of both auxiliary materials are different. The main components of coke ash are SiO ₂ and Al ₂ O ₃ .

The results of the gasification reaction test are considered to be due to the following gasification reactions caused by the difference in the components of the packing particles. Hereinafter, a description will be given with reference to FIG.
First, in the case of coke alone shown in FIG. 3 (A), when carbon on the surface is gasified by coke gasification, ash remains on the surface. As described above, this ash has an extremely high melting point made of SiO ₂ and Al ₂ O ₃ and does not easily melt off. As a result, it covers the surface of the coke and prevents contact with the reaction gas, so the gasification rate is not so fast.

When coke and silica shown in FIG. 3B are mixed (when coke particles and silica are in contact), coke ash is generated by coke gasification as described above. This coke ash is believed to react with silica in contact, a large change in its melting point and coke ash reaction consisting of silica and SiO ₂ and Al ₂ O ₃ to SiO ₂ as a main component occurs Absent. Therefore, since the area of the portion where the coke and the quartzite are in contact with each other is hindered from contacting with the reaction gas, it is considered that the gasification reaction area of the coke decreases and the gasification rate decreases.

On the other hand, when coke and limestone shown in FIG. 3C are mixed (when coke particles and limestone are in contact), coke ash produced by gasification may react with limestone. CaO, which is the main component of limestone, has an extremely high melting point of 2567 ° C., but it easily forms a compound with SiO ₂ and Al ₂ O ₃ contained in coke ash and lowers the melting point. In this case, the lowest melting point is about 1170 ° C. Therefore, when the low melting point compound produced by the reaction between coke ash and limestone melts and melts, the surface of the coke is cleaned, and the contact between carbon and CO _{2 on} the surface of the coke particles is promoted, so the apparent coke gas It is considered that the chemical reaction area increases and the reaction between CO ₂ and carbon is promoted.
From the above, it is considered that the coke reactivity can be suppressed by charging a substance having a high CaO content so as not to contact the coke as much as possible. On the other hand, it is considered that a substance having a high SiO ₂ content such as silica stone is effective in suppressing coke reactivity if it is charged so as to come into contact with coke as much as possible.

Next, the limit value of the CaO content of a substance that promotes coke gasification and the limit value of the SiO ₂ content of a substance that suppresses coke gasification were examined. Dust agglomerates were prepared using dust A, dust B and Portland cement (binder) shown in Table 1, and further using silica stone and limestone as necessary. At that time, the dust agglomerates having different CaO contents and the dust agglomerates having different SiO ₂ contents can be prepared by adjusting the composition of dust A, dust B and Portland cement and adding silica stone and limestone as necessary. The compound was obtained. The dust agglomerate was mixed with coke and charged into a crucible, and the same gasification test as described above was performed. The result is shown in FIG. FIG. 4 shows the relationship between the CaO content of the dust agglomerate and the gasification reaction rate of the coke (FIGS. 4A and 4B), the SiO ₂ content of the dust agglomerate and the gasification reaction of the coke. 4 shows the relationship with the velocity (FIGS. 4 (c) and (d)). The gasification reaction rate in the case of coke alone is set to “1.0”, and the gasification reaction rate in each case is indexed. Indicated. Incidentally, FIG. 4 (b) is an enlarged view of the CaO content 2～8Mass% portion of FIG. 4 (a), FIG. 4 (d), SiO ₂ content of FIG. 4 (c) 92 to The 98 mass% portion is enlarged.
As a result of this gasification test, as shown in FIGS. 4A and 4B, it was found that when the CaO content of the substance in contact with the coke is 5 mass% or more, the gasification is switched to promotion. Further, as shown in FIG. 4 (c), (d) , the SiO ₂ content of substances in contact with the coke becomes more 95 mass%, it was found that the switch to the gasification suppressed.

From the above test results, the following can be said about the raw fuel charging state in the furnace. Since secondary materials and dust agglomerates with a CaO content of 5 mass% or more promote the gasification reaction, it is desirable not to charge them in a vertical melting furnace. However, secondary materials such as limestone hatch coke ash. It is necessary to charge in order to facilitate discharge from the furnace, and the dust agglomerate may be charged as an iron source. Therefore, it is preferable to insert such a substance so as not to come into contact with coke as much as possible. For this reason, for example, it is preferable to charge the auxiliary raw material and the dust agglomerate having a CaO content of 5 mass% or more so as to be concentric with the coke in the vertical melting furnace. Specifically, it is preferable that the same material is charged in the center of the furnace, and coke is charged in the outer periphery of the furnace wall. On the other hand, since the raw material (usually auxiliary material) having a SiO ₂ content of 95 mass% or more suppresses the gasification reaction by contacting with the coke particles, it can be charged in a state where it contacts with the coke as much as possible. preferable.

In the present invention, the main raw fuel charged in the furnace is an iron source mainly composed of iron-based scrap, coke, and a slagging agent.
Iron scrap includes iron scrap and casting scrap, but one or more of these can be used, and the iron source is mainly composed of such iron scrap (that is, the ratio of iron scrap is 50 mass). % Or more). As iron sources other than iron-based scrap, agglomerates of iron-containing dust and / or iron-containing sludge (hereinafter referred to as “iron-containing dust / sludge agglomerate”), massive iron ore, sintered Examples include ore (sintered powdered iron ore), granulated pellets of powdered iron ore, and the like, and one or more of these can be used. The details of the iron-containing dust / sludge agglomerate will be described later.
Examples of the faux-forming agent include limestone and quartzite, and one or more of these can be used.
In addition to the above raw fuel, carbon materials such as pulverized coal, charcoal, and waste plastic may be charged or blown into the furnace.

At least the raw fuel consisting of iron source mainly composed of iron-based scrap, coke and slagging agent is charged at regular intervals from the top of the vertical melting furnace, and each time the raw fuel is charged into the furnace A raw fuel layer is formed on the surface. The raw fuel charging method is as follows: (I) The raw fuel is loaded into a bucket having a gate that can be opened at the bottom, and the gate at the bottom of the bucket is opened at the top of the furnace. And (II) a method of charging raw fuel into the furnace from a charging chute provided at the top of the furnace, and (III) a method of using (I) and (II) in combination. Among these, the method (I) is the most common.
In a vertical melting furnace charged with raw fuel, molten iron is produced by melting an iron source mainly by the combustion heat of coke.

  FIG. 5 shows an example of a vertical melting furnace provided for carrying out the present invention and a method of charging raw fuel into the vertical melting furnace. The furnace body 1 is usually cylindrical, and the raw fuel is charged from the top of the furnace by gravity. In this embodiment, the raw fuel is loaded into the furnace by the method (I). That is, the bucket 2 containing the raw fuel (in FIG. 5, iron-based scrap 3, coke 4 and iron making agent 5) is moved to the top of the furnace, the gate 20 at the bottom of the bucket is opened, the raw fuel is dropped, and the raw fuel is removed. Charge into the furnace. The bucket 2 has various shapes, sizes, and the like, but basically may be of any type as long as it has a function of charging raw fuel into the furnace body 1. In addition, although FIG. 5 has shown in the state which carried out the longitudinal cross-section of the bucket 2, hatching of the cross section is abbreviate | omitted.

  A plurality of tuyere 7 (air blowing ports) are installed in the lower part of the furnace body 1 in the circumferential direction. Air or oxygen-enriched air blown by a blower (not shown) is introduced into each tuyere 7 through an annular pipe 6 (header pipe), and blown into the furnace body 1 from this tuyere 7. The air to be blown or the oxygen-enriched air may be at normal temperature, or may be heated (for example, several hundred degrees C.). Equipment for that purpose is required for raising the temperature, and fuel is also required. However, since the amount of coke used can be reduced by that amount, it may be selected in consideration of economic efficiency. In the furnace main body 1, air or oxygen-enriched air burns coke, and the iron source is melted by the combustion heat generated thereby to produce hot metal. On the other hand, the ash content of the coke 4 reacts with the kneading agent 5 and melts into slag. Hot metal and slag are discharged out of the furnace from the outlet 8 in a molten state.

In the method of the present invention, in the raw fuel layer formed by charging the raw fuel for one time from the top of the furnace, the raw material layer x made of the raw material having a CaO content of 5 mass% or more is unevenly distributed in the central part of the furnace. Formed in contact with layer c.
In addition, in the raw fuel layer formed by charging the raw fuel for one time from the top of the furnace, the raw material layer y made of the raw material having a SiO ₂ content of 95 mass% or more is formed in contact with the coke layer c. It is preferable.
Here, the furnace wall peripheral part is an annular area near the furnace wall in the horizontal cross section of the furnace body, and the furnace central part is an area inside thereof.

A typical example of a raw material having a CaO content of 5 mass% or more is a CaO-based fossilizing agent such as limestone. For example, an iron-containing iron-containing dust / sludge agglomerate is also a binder such as Portland cement. Depending on the CaO contained, the CaO content may be 5 mass% or more, and such an agglomerated material is a raw material having a CaO content of 5 mass% or more. The same applies to granulated pellets of sintered ore and powdered iron ore. Therefore, the raw material having a CaO content of 5 mass% or more is at least one selected from these.
A typical example of the raw material having a SiO ₂ content of 95 mass% or more is a non-CaO-based fossilizing agent such as silica stone, but is not limited thereto.

Hereinafter, more specific embodiments of the present invention will be described.
FIG. 6 described below shows the furnace body 1 in a longitudinal section, and FIGS. 7 to 11 and FIGS. 14 to 16 show the bucket 2 in a longitudinal section. The hatching of the cross section is omitted.
In a more specific embodiment of the present invention, the raw fuel layer A formed by one charge of raw fuel from the top of the furnace has at least an iron-based scrap layer s, a coke layer c, and a CaO content of 5 mass%. In addition to the material layer x composed of the above materials and the material layer y composed of a material having a SiO ₂ content of 95 mass% or more, each layer is formed in any of the following forms (i) to (iv): .

(I) As shown in FIG. 6 (A), an iron-based scrap layer s (iron-based scrap 3) is formed in the lowermost layer, and a coke layer c (coke 4) is formed in the upper peripheral portion of the furnace wall. A raw material layer x (for example, limestone 5b) is formed on the part, and a raw material layer y (for example, silica 5a) is formed on the coke layer c.
(Ii) As shown in FIG. 6 (B), an iron-based scrap layer s (iron-based scrap 3) is formed in the lowermost layer, and a coke layer c (coke 4) is formed around the furnace wall in the upper layer, and the center of the furnace A raw material layer x (for example, limestone 5b) is formed on the lower side of the section, and a raw material layer y (for example, silica 5a) is formed on the upper side of the furnace center.
(Iii) As shown in FIG. 6C, an iron-based scrap layer s (iron-based scrap 3) is formed in the lowermost layer, a coke layer c (coke 4) is formed in the upper layer, and the furnace in the upper layer A raw material layer y (for example, silica 5a) is formed around the wall, and a raw material layer x (for example, limestone 5b) is formed at the furnace center.
(Iv) As shown in FIG. 6 (D), an iron-based scrap layer s (iron-based scrap 3) is formed in the lowermost layer, a coke layer c (coke 4) is formed around the furnace wall in the upper layer, and the center of the furnace A raw material layer y (for example, silica stone 5a) is formed on the lower side of the section, and a raw material layer x (for example, limestone 5b) is formed on the upper side of the furnace center.

Of the above forms (i) to (iv) (the forms shown in FIGS. 6 (A) to (D)), the degree of effect by reducing the contact between the coke and the raw material having a CaO content of 5 mass% or more is as small as possible. , (I), (ii), (iv)> (iii). On the other hand, the degree of the effect by being able to increase the contact between the coke and the raw material having a SiO ₂ content of 95 mass% or more is as follows: (i)>(iii)> (ii), (iv). Therefore, the overall effect of the above two effects is (i)> (ii), (iii), (iv).
In addition, embodiment of this invention is not limited to the thing of FIG. 6 (A)-(D).

In order to form the raw fuel layer A as shown in FIG. 6 by the raw fuel charging method using the bucket 2 as shown in FIG. 5 (method (I) described above), the following method is adopted. be able to.
In general, as shown in FIG. 14, the distribution state (charged state) of raw fuel in the bucket 2 in the conventional method is as follows: iron-based scrap 3 at the bottom layer, coke 4 thereon, and further auxiliary materials thereon. some limestone 5b (CaO Keizokasuzai = CaO content of 5 mass% or more ingredients) and silica 5a (SiO ₂ content of 95 mass% or more ingredients), and each is distributed in layers, the furnace from the bucket 2 This distribution state is maintained even when the battery is inserted into the battery.

On the other hand, in order to form the raw fuel layer A as shown in FIG. 6 in the furnace, when the raw fuel is charged into the bucket 2, the raw fuel layer A ₀ in the bucket 2 is at least iron. A system scrap layer s ₀ , a coke layer c ₀ , a raw material layer x _{0 made of} a raw material with a CaO content of 5 mass% or more, and a raw material layer y ₀ made of a raw material with a SiO ₂ content of 95 mass% or more, Each layer is formed in any one of the following forms (a) to (d).
In the following (A) to (D), the bucket inner wall peripheral portion is an annular region near the bucket wall surface in the bucket horizontal section, and the bucket central portion is an inner region thereof.

(A) As shown in FIG. 7A, an iron-based scrap layer s ₀ (iron-based scrap 3) is formed in the lowermost layer, and a coke layer c ₀ (coke 4) and a bucket are formed around the inner wall of the upper bucket bucket. material layer x ₀ in the central portion _(e.g., limestone 5b) are formed respectively, the raw material layer y ₀ on the upper layer of the coke layer c _{0 (e.g.,} silica 5a) so that is formed.
(B) As shown in FIG. 7B, an iron-based scrap layer s ₀ (iron-based scrap 3) is formed in the lowermost layer, and a coke layer c ₀ (coke 4) and bucket are formed around the inner wall of the upper bucket bucket. A raw material layer x ₀ (for example, limestone 5b) is formed on the lower side of the central portion, and a raw material layer y ₀ (for example, silica 5a) is formed on the upper side of the central portion of the bucket.
(C) As shown in FIG. 7C, an iron-based scrap layer s ₀ (iron-based scrap 3) is formed in the lowermost layer, a coke layer c ₀ (coke 4) is formed in the upper layer, and the upper layer A raw material layer y ₀ (for example, silica 5a) is formed around the inner wall of the bucket, and a raw material layer x ₀ (for example, limestone 5b) is formed at the central portion of the bucket.
(D) As shown in FIG. 7D, an iron-based scrap layer s ₀ (iron-based scrap 3) is formed in the lowermost layer, and a coke layer c ₀ (coke 4) and a bucket are formed around the inner wall of the upper bucket bucket. A raw material layer y ₀ (for example, silica 5a) is formed on the lower side of the central portion, and a raw material layer x ₀ (for example, limestone 5b) is formed on the upper side of the central portion of the bucket.

Then, as shown in FIG. 5, the raw fuel in the bucket 2 is charged into the furnace by opening the gate 20 at the bottom of the bucket at the top of the furnace. At this time, the distribution state of the raw fuel layer A ₀ in the bucket 2 is maintained as it is, and the raw fuel layer A shown in FIG. 6 is formed in the furnace. That is, FIG. 7A shows the raw fuel layer A in FIG. 6A, FIG. 7B shows the raw fuel layer A in FIG. 6B, and FIG. 7C shows the raw fuel layer A in FIG. As shown in FIG. 7D, the raw fuel layer A shown in FIG. 6D is formed.

  Since the raw fuel whose distribution state (charging state) in the bucket 2 is controlled as described above is mixed when charged into the vertical melting furnace, the distribution may be disturbed. The discharge behavior of raw fuel from the bottom of the bucket was observed outside the furnace. As a result, it was found that when iron-based scrap was arranged in the lowermost layer, the raw fuel in the bucket 2 was discharged only after the gate 20 at the bottom of the bucket was fully opened, and the raw fuel dropped almost vertically. Further, since the charging surface of the furnace main body 1 is substantially horizontal, the dropped raw fuel is deposited in the furnace main body 1 in a state where the deposited shape in the bucket 2 is substantially maintained, and the raw fuel shown in FIG. It was found that layer A was formed.

Attempts, the order of the raw fuel to be deposited in the bucket 2, from the lower side auxiliary materials (raw material layer x ₀ and the raw material layer y _0), coke (coke layer c _0), ferrous scrap (iron-based scrap layer s ₀ ), And when it becomes fine to coarse particles from the lower layer side to the upper layer side, the gate 20 at the bottom of the bucket begins to open and the outflow of the auxiliary material on the lower layer starts, and the lower layer in the bucket 2 Since the raw material in the central portion was discharged first, it was found that the deposition shape of the raw fuel in the furnace body 1 could not maintain the deposition shape in the bucket 2. Therefore, when charging the raw fuel in the bucket 2 are charged above the ferrous scrap, the iron-based scrap layer s ₀ is formed in the lowermost layer is desirable.

Next, a method for forming a raw fuel layer A ₀ as shown in FIG. 7 (A) ~ (D) in the bucket 2. Here, the case where the raw material having a CaO content of 5 mass% or more is limestone 5b and the raw material having a CaO content of less than 5 mass% is silica stone 5a will be described.
FIG. 15 shows a conventional method for charging raw fuel into the bucket 2 corresponding to FIG. The four hoppers 9a to 9d are a scrap charging hopper 9a, a coke charging hopper 9b, a limestone charging hopper 9c, and a quartz stone charging hopper 9d, respectively. The bucket 2 is initially charged with a predetermined amount of iron scrap 3 under the scrap charging hopper 9a, and then moved under the coke charging hopper 9b, where a predetermined amount of coke 4 is transferred. It is inserted. Next, the bucket 2 is moved under the limestone charging hopper 9c to be charged with a predetermined amount of limestone 5b, and finally is moved under the quarrystone charging hopper 9d to be charged with a predetermined amount of silica stone 5a. Is done. As a result, the raw fuel in the bucket 2 is stacked in layers as shown in FIG.

8 to 11 show a charging method for forming the raw fuel layer A ₀ shown in FIGS. 7A to 7D in the bucket 2.
Figure 8 is a charging method for forming a raw fuel layer A ₀ shown in FIG. 7 (A) in the bucket 2, first the bucket 2, a predetermined amount under the scrap instrumentation necessity hopper 9a The scrap 3 is charged and then moved under the coke charging hopper 9b, where a predetermined amount of coke 4 is charged. At that time, a cylindrical charging guide 12 is arranged in the center of the bucket 2 in advance, and the cap-shaped charging guide 10 is placed between the hopper and the bucket 2 (the upper end position of the charging guide 12). If it arrange | positions, the coke 4 will be inserted only into the outer side (bucket inner wall peripheral part) of the guide 12 for charging. Next, the bucket 2 moves under the limestone charging hopper 9c and a predetermined amount of limestone 5b is charged. At this time, the limestone 5b is placed only inside the cylindrical charging guide 12. Try to charge. At the time of this charging, a charging guide 11 having a ring shape and the upper surface 110 inclined downward in the centripetal direction may be disposed between the hopper and the bucket 2. Thereafter, the charging guide 12 is extracted, and finally moved below the silica stone charging hopper 9d to load the silica 5a. At this time, the cap-shaped charging guide 10 is replaced with the hopper and the bucket 2. By arranging it in between, the silica 5a can be charged only in the peripheral part of the bucket inner wall at the top of the coke 4. The charging of the silica 5a may be performed before the charging guide 12 is extracted. Thus, the charging of the raw fuel into the bucket 2 is completed.
FIG. 12 shows a charging guide 10 for charging raw fuel only to the peripheral part of the inner wall of the bucket. FIG. 12 (A) is a plan view and FIG. 12 (B) is a side view. Moreover, FIG. 13 shows the charging guide 11 for charging the raw fuel only in the central portion of the bucket. FIG. 13 (A) is a plan view and FIG. 13 (B) is a side view.

Further, FIG. 9 is a charging method for forming a raw fuel layer A ₀ shown in FIG. 7 (B) in the bucket 2, first the bucket 2 is first Tokoro under scrap instrumentation necessity hopper 9a A predetermined amount of scrap 3 is charged, and then moved to a position below the coke charging hopper 9b, where a predetermined amount of coke 4 is charged. At that time, similarly to FIG. 8, a cylindrical charging guide 12 is arranged in the center of the bucket 2 in advance, and the cap-shaped charging guide 10 is placed between the hopper and the bucket 2 (charging guide). 12 at the upper end position), the coke 4 is charged only outside the charging guide 12 (at the periphery of the bucket inner wall). Next, the bucket 2 sequentially moves below the limestone charging hopper 9c and below the quarrystone charging hopper 9d, and a predetermined amount of limestone 5b and quarrystone 5a are sequentially charged. The limestone 5b and the quartz stone 5a are charged only inside the cylindrical charging guide 12, respectively. As a result, a layer of limestone 5b is formed on the lower side in the charging guide 12, and a layer of silica stone 5a is formed on the upper side. At the time of this charging, a charging guide 11 having a ring shape and the upper surface 110 inclined downward in the centripetal direction may be disposed between the hopper and the bucket 2. Thereafter, the charging guide 12 is extracted, and the charging of the raw material into the bucket 2 is completed.

Further, FIG. 10 is a charging method for forming a raw fuel layer A ₀ shown in FIG. 7 (C) in the bucket 2, the bucket 2 is initially Tokoro under scrap instrumentation necessity hopper 9a A certain amount of iron-based scrap 3 is charged, and then moves under the coke charging hopper 9b, where a predetermined amount of coke 4 is charged. Next, the bucket 2 moves below the silica hopper 9d and a predetermined amount of silica 5a is inserted. At this time, the cap-shaped guide 10 is inserted between the hopper and the bucket 2. By arranging it, the silica 5a can be charged only in the periphery of the bucket inner wall. The bucket 2 finally moves under the limestone charging hopper 9c and is charged with a predetermined amount of limestone 5b. At that time, the limestone 5b can be charged only in the central portion of the bucket by placing the charging guide 11 having a ring shape with the upper surface 110 inclined downward in the centripetal direction between the hopper and the bucket 2. . Thus, the charging of the raw fuel into the bucket 2 is completed.

Further, 11 is a charging method for forming a raw fuel layer A ₀ shown in FIG. 7 (D) in the bucket 2, first the bucket 2 is first Tokoro under scrap instrumentation necessity hopper 9a A predetermined amount of scrap 3 is charged, and then moved to a position below the coke charging hopper 9b, where a predetermined amount of coke 4 is charged. At that time, similarly to FIG. 8, a cylindrical charging guide 12 is arranged in the center of the bucket 2 in advance, and the cap-shaped charging guide 10 is placed between the hopper and the bucket 2 (charging guide). 12 at the upper end position), the coke 4 is charged only outside the charging guide 12 (at the periphery of the bucket inner wall). Next, the bucket 2 sequentially moves under the quarry stone charging hopper 9d and under the limestone charging hopper 9c, and a predetermined amount of silica stone 5a and limestone 5b are sequentially charged. The silica 5a and the limestone 5b are charged only into the cylindrical charging guide 12, respectively. As a result, a layer of silica 5a is formed on the lower side in the charging guide 12, and a layer of limestone 5b is formed on the upper side. At the time of this charging, a charging guide 11 having a ring shape and the upper surface 110 inclined downward in the centripetal direction may be disposed between the hopper and the bucket 2. Thereafter, the charging guide 12 is extracted, and the charging of the raw material into the bucket 2 is completed.

As described above, when the raw fuel is charged into the furnace using the bucket 2, the state of the raw fuel in the bucket (the form of the raw fuel layer A ₀ ) is adjusted in the furnace. Is a method for controlling the charging state of raw fuel (form of the raw fuel layer A), but the charging mechanism of the furnace body 1 of the vertical melting furnace (for example, a charging chute installed at the top of the furnace) It may be used to control the charging state of raw fuel (form of raw fuel layer A) in the furnace (methods (II) and (III) described above).

In the embodiment shown in FIG. 16, iron scrap, coke, and a part of the slagging agent are charged into the furnace using the bucket 2, and a specific charging device (charging chute 13 is provided at the top of the furnace body 1. ) And using this charging device, a part of the slagging agent and the like is charged.
In this embodiment, raw fuel other than raw material having a SiO ₂ content of 95 mass% or more is charged into a bucket 2 having a gate 20 that can be opened at the bottom, and the raw fuel is charged from the bucket 2 into the furnace. I do. The raw fuel layer A ₀ in the bucket 2 is composed of at least an iron-based scrap layer s ₀ , a coke layer c _0, and a raw material layer x ₀ made of a raw material having a CaO content of 5 mass% or more, and iron in the lowermost layer. A system scrap layer s ₀ (iron-based scrap 3) is formed, a coke layer c ₀ (coke 4) is formed on the upper layer, and a raw material layer x ₀ (for example, limestone 5b) is formed in the center of the upper bucket. So that

Then, by opening the gate 20 at the bottom of the bucket at the top of the furnace, the raw fuel in the bucket 2 is charged into the furnace, and then the SiO ₂ content is 95 mass% from the charging chute 13 provided at the top of the furnace. By charging the above raw material (for example, silica 5a) into the furnace, each layer is formed in the form of (iii) in the raw fuel layer A formed by the raw fuel charge for one time from the top of the furnace. It is intended to be done. FIG. 17 shows the raw fuel layer A of the form (iii) formed in the furnace as described above, and an iron-based scrap layer s (iron-based scrap 3) is formed in the lowermost layer, and its upper layer Then, a coke layer c (coke 4) is formed, and a raw material layer x (for example, limestone 5b) is formed in the furnace center portion of the upper layer, and a raw material layer y (for example, silica stone 5a) is formed in the periphery of the furnace wall.

As another embodiment, the bucket 2 has an iron-based scrap layer s ₀ (iron-based scrap 3) formed in the lowermost layer, and a coke layer c ₀ (coke 4) in the periphery of the bucket inner wall of the upper layer. A raw material layer x ₀ (for example, limestone 5b) may be formed in the bucket central portion. In this case, by opening the gate 20 at the bottom of the bucket at the top of the furnace, after charging the raw fuel in the bucket 2 into the furnace, the SiO ₂ content is 95 mass from the charging chute 13 provided at the top of the furnace. % Of raw material (for example, silica 5a) is charged into the furnace, and in the raw fuel layer A formed by one time raw fuel charging from the top of the furnace, each layer is in the form of (i) It is formed. That is, an iron-based scrap layer s (iron-based scrap 3) is formed in the lowermost layer, a coke layer c (coke 4) is formed around the upper furnace wall, and a raw material layer x (for example, limestone 5b) is formed in the center of the furnace. A raw material layer y (for example, silica 5a) is formed on the coke layer c.

The charging chutes 13 are provided at a plurality of locations on the furnace top of the furnace body 1, but are preferably provided at four or more locations in the circumferential direction of the furnace body, and more preferably about the same number as the tuyere 7. A flow rate adjusting valve 14 is provided below the charging chute 13 so that a predetermined amount of raw material (raw material having a SiO ₂ content of 95 mass% or more) can be charged at an arbitrary timing.

Next, the iron-containing dust / sludge agglomerate will be described.
The iron-containing dust / sludge agglomerate may be any one of iron-containing dust and iron-containing sludge, or any material obtained by solidifying a raw material mainly composed of iron-containing dust and sludge. However, in general, one or more types of iron-containing dust and iron-containing sludge are mixed with a hydraulic binder, and if necessary, water is added to the raw material containing carbonaceous powder for reduction, and then molded. The molded product is then hydrated and cured to form an agglomerated product.

  The iron-containing dust is dust containing iron oxide and / or metallic iron, and the type thereof is not particularly limited, but typical examples include steel-making dust generated in a steel manufacturing process. The steelmaking dust includes hot metal pretreatment dust generated in the hot metal pretreatment process, converter dust generated in the converter decarburization process, electric furnace dust generated in the electric furnace, and the like. These steelmaking dusts are collected by collecting dust from the exhaust gas generated in the steelmaking process. Examples of iron-containing dust other than steelmaking dust include blast furnace dust and rolling dust.

The iron-containing sludge is a sludge containing iron oxide and / or metallic iron, and there is no particular limitation on the type thereof, but it is sludge formed by collecting various types of dust as described above with a wet dust collector. Is a typical example.
As said hydraulic binder, 1 or more types, such as various cements, such as a Portland cement, a blast furnace cement, an alumina cement, a fly ash cement, blast furnace granulated slag fine powder, quick lime, can be used, for example. In general, the blending amount of the hydraulic binder in the raw material is preferably about 2 to 25 mass% from the viewpoints of strength development and suppression of slag generation.

The molding process can be performed by any method such as molding using a mold, extrusion molding, roll press molding, etc. However, if the molding is made dense, the iron-containing dust / sludge agglomerate tends to increase in strength. For this reason, it is preferable to mold as high a density as possible. For this reason, it is preferable to compression-mold the mixture of raw material and water or to perform compression molding while vibrating. Specifically, it is preferable to perform molding using a compression molding machine such as a briquette molding machine, a press molding machine, an extrusion molding machine, or the like having a vibration function.
Although the shape of a molded product is arbitrary, in order to suppress powdering at the time of charging to a furnace as much as possible, it is preferable that there are few corners. Also, the size of the molded product is arbitrary, but if it is too small, the pressure loss of the furnace will increase when it is charged into the vertical melting furnace, while if it is too large, it will agglomerate when charged in the vertical melting furnace. In general, a size of about 20 to 2000 cc in volume is preferable because a reduction and dissolution delay due to a temperature rise delay in the center of the compound occurs.

A molded product obtained by molding a mixture of a raw material and water is cured for a certain period of time in order to be hydrated and cured by a hydraulic binder. The curing method and period may be arbitrary. For example, after performing primary curing with steam, secondary curing in the atmosphere may be performed. The curing period is preferably as short as possible from the aspects of curing space and productivity, but may be appropriately selected according to the required strength after curing. Generally, about 1 to 7 days is preferable.
Further, the iron-containing dust / sludge agglomerate may be produced by a method other than the production method in which the molded body is hydrated and cured using a hydraulic binder as described above. For example, what was obtained by solidifying a molded object using binders (for example, molasses and an organic binder) other than a hydraulic binder may be used.

Iron scrap was melted using the combustion heat of coke using a vertical melting furnace with a furnace inner diameter of 3.4 m to produce hot metal (pig iron).
Table 2 shows the composition of the raw fuel used. In general, iron sources are mixed and used in consideration of supply and demand and economic efficiency. In this example, among steel scrap standards established by the Japan Iron Source Association, which are widely used, those corresponding to H2 were mainly used (scrap A). This standard is related to the size of the scrap, and there is no standard for the component, but it contains impurities other than iron due to adhering earth and sand although it is a trace amount. Since these impurity concentrations are necessary for designing the slag component, Table 2 shows the estimated values for the composition other than iron. However, since the components vary depending on the lot, the components are not necessarily the same. Scrap B is pig iron scrap generated in the steelworks.

Dust A and B are two typical types of various powders generated in steelworks, and after adding a suitable amount of water and hydraulic Portland cement (binder), they are mixed into a 50 mm lump. And then hardened by curing for a predetermined time to obtain a dust agglomerated product. The dust agglomerate has a CaO content of 9 mass%. The iron content in the dust is often contained in the form of iron oxide, but can be reduced and melted in a vertical melting furnace as an iron source to form molten iron. As a source other than the iron source, coke as a heat source, limestone and quartzite as an additive (auxiliary raw material for adjusting slag components) were used. Limestone, dust agglomerate the raw material CaO content is more than 5 mass%, silica is SiO ₂ content falls under 95 mass% or more ingredients.
In order to maintain the fluidity of the slag, as slag basicity (value obtained by dividing CaO concentration in slag (mass%) of SiO ₂ concentration (mass%)) becomes a constant value (0.92), The blending amount of the faux-making agent was appropriately adjusted.
Table 3 shows the operating conditions and exhaust gas composition of the present invention and the comparative examples.

Invention Example 1 had an output amount of 70 t / hr, and was charged with 900 kg / t of slap A and 120 kg / t of scrap B as iron sources. As shown in FIG. 5, the raw fuel is charged from the top of the furnace using the bucket 2, and the raw fuel layer A in the furnace is in the form shown in FIG. 6A, that is, the iron-based scrap layer s is formed in the lowermost layer. The coke layer c is formed around the furnace wall and the raw material layer x (limestone layer) is formed at the center of the furnace, and the raw material layer y (silica stone layer) is formed above the coke layer c. .
In the present invention example 1, since the low melting point slag was generated and the surface of the coke was cleaned and the gasification reaction was not promoted, the gas utilization rate was relatively high, and the coke ratio was also high. It was as low as 180 kg / t.

In Invention Example 2, the amount of slag was 70 t / hr, and 900 kg / t of slap A and 120 kg / t of scrap B were charged as iron sources. As shown in FIG. 5, the raw fuel is charged from the top of the furnace using the bucket 2, and the raw fuel layer A in the furnace is in the form shown in FIG. 6B, that is, the iron-based scrap layer s is formed in the lowermost layer. The coke layer c is formed around the upper furnace wall, the raw material layer x (limestone layer) is formed at the lower part of the central part of the furnace, and the raw material layer y (silica stone layer) is formed at the upper part of the central part of the furnace. .
In the present invention example 2, since the low melting point slag was generated to clean the surface of the coke and the gasification reaction was not promoted, the gas utilization rate was relatively high, and the coke ratio was also high. It was as low as 182 kg / t.

Invention Example 3 had an output amount of 70 t / hr, and was charged with 900 kg / t of scrap A and 120 kg / t of scrap B as iron sources. As shown in FIG. 5, the raw fuel is charged from the top of the furnace using the bucket 2, and the raw fuel layer A in the furnace is in the form shown in FIG. 6C, that is, the iron-based scrap layer s is formed in the lowermost layer. A coke layer c was formed as an upper layer, and a raw material layer y (silica stone layer) was formed around the furnace wall of the upper layer, and a raw material layer x (limestone layer) was formed at the furnace center.
In this invention example 3, since the low melting point slag was generated and the surface of the coke was cleaned and the gasification reaction was not promoted, the gas utilization rate was relatively high, and the coke ratio was also high. It was as low as 185 kg / t.

Invention Example 4 had an output amount of 70 t / hr, and was charged with 900 kg / t of slap A and 120 kg / t of scrap B as iron sources. As shown in FIG. 5, the raw fuel is charged from the top of the furnace using the bucket 2, and the raw fuel layer A in the furnace is in the form shown in FIG. 6D, that is, the iron-based scrap layer s is formed in the lowermost layer. The coke layer c is formed around the upper wall of the furnace layer, the raw material layer y (silica stone layer) is formed on the lower side of the central part of the furnace, and the raw material layer x (limestone layer) is formed on the upper side of the central part of the furnace. .
In this invention example 4, since the low melting point slag was generated and the surface of the coke was cleaned and the gasification reaction was not promoted, the gas utilization rate was relatively high and the coke ratio was also high. It was as low as 183 kg / t.

In Comparative Example 1, the output amount was 70 t / hr, and slap A as an iron source was charged at 900 kg / t and scrap B was charged at 120 kg / t. The raw fuel was put into the bucket 2 in the state as shown in FIG. 14, and the raw fuel was charged from the top of the furnace using the bucket 2 as shown in FIG. In the raw fuel layer in the furnace, an iron-based scrap layer, a coke layer, a limestone layer, and a silica layer were uniformly formed from the lower layer side.
In Comparative Example 1, a low melting point slag was generated to clean the surface of the coke, and the gas utilization rate was lowered to promote the gasification reaction, and the coke ratio was as high as 201 kg / t.

DESCRIPTION OF SYMBOLS 1 Furnace body 2 Bucket 3 Iron-based scrap 4 Coke 5 Coagulant 5a Silica stone 5b Limestone 6 Annular pipe 7 Feather 8 Outlet 9a, 9b, 9c, 9d Hopper 10, 11, 12 Charging guide 13 Charging chute 14 Flow control valve 20 Gate 110 Upper surface A, A ₀ Raw fuel layer s, s ₀ Iron-based scrap layer c, c ₀ Coke layer
Raw material layer made of raw material with x, x ₀ CaO content of 5 mass% or more
Raw material layer made of raw material with y, y ₀ SiO ₂ content of 95 mass% or more

Claims (5)

From the top of the vertical melting furnace, an iron source mainly composed of iron-based scrap, coke and iron making agent are charged as raw fuel, and the iron source is mainly melted by the combustion heat of the coke to produce hot metal. A method,
The raw fuel layer formed by charging the raw fuel for one time from the top of the furnace is at least an iron-based scrap layer (s), a coke layer (c), and a raw material layer made of a raw material having a CaO content of 5 mass% or more ( x), and a raw material layer (y) made of a raw material having a SiO ₂ content of 95 mass% or more, and each layer is formed in any of the following forms (i) to (iv), and in this form, CaO A method for producing hot metal using a vertical melting furnace, wherein a raw material layer (x) made of a raw material having a content of 5 mass% or more is formed in contact with a coke layer (c).
(I) An iron-based scrap layer (s) is formed in the lowermost layer, a coke layer (c) is formed in the periphery of the furnace wall of the upper layer, and a raw material layer (x) is formed in the center of the furnace, and the coke layer (c The raw material layer (y) is formed on the upper layer.
(Ii) An iron-based scrap layer (s) is formed in the lowest layer, a coke layer (c) around the upper wall of the furnace wall, a raw material layer (x) on the lower side of the furnace center, and the upper side of the furnace center The raw material layer (y) is formed respectively.
(Iii) An iron-based scrap layer (s) is formed in the lowermost layer, a coke layer (c) is formed in the upper layer, a raw material layer (y) is formed around the upper furnace wall, and a raw material layer ( x) is formed respectively.
(Iv) An iron-based scrap layer (s) is formed in the lowest layer, a coke layer (c) around the upper furnace wall, a raw material layer (y) on the lower side of the furnace center, and an upper side of the furnace center The raw material layer (x) is formed respectively. In the raw fuel layer formed by one charge of raw fuel from the top of the furnace, the raw material layer (y) made of raw material having a SiO ₂ content of 95 mass% or more is formed in contact with the coke layer (c). A method for producing hot metal using the vertical melting furnace according to claim 1.   2. The raw material having a CaO content of 5 mass% or more is at least one selected from agglomerates of a CaO-based fouling agent, iron-containing dust and / or iron-containing sludge. Or the manufacturing method of the hot metal using the vertical melting furnace as described in 2. Raw fuel is charged into a bucket having an openable gate at the bottom, and the raw fuel layer in the bucket has at least an iron-based scrap layer (s ₀ ), a coke layer (c ₀ ), and a CaO content of 5 mass. % Of a raw material layer (x ₀ ) made of a raw material of at least% and a raw material layer (y ₀ ) made of a raw material having a SiO ₂ content of 95 mass% or more, and each layer is any of the following (a) to (e) To be formed in some form,
(A) An iron-based scrap layer (s ₀ ) is formed in the lowermost layer, a coke layer (c ₀ ) is formed around the inner wall of the upper bucket bucket, and a raw material layer (x ₀ ) is formed in the middle of the bucket. A raw material layer (y ₀ ) is formed on the layer (c ₀ ).
(A) An iron-based scrap layer (s ₀ ) is formed in the lowest layer, a coke layer (c ₀ ) around the inner wall of the bucket upper layer, a raw material layer (x ₀ ) at the lower side of the bucket center, and the bucket center A raw material layer (y ₀ ) is formed on the upper side of each.
(C) An iron-based scrap layer (s ₀ ) is formed in the lowermost layer, a coke layer (c ₀ ) is formed in the upper layer, a raw material layer (y ₀ ) around the inner wall of the upper bucket, and a central portion of the bucket A raw material layer (x ₀ ) is formed.
(D) An iron-based scrap layer (s ₀ ) is formed in the lowermost layer, a coke layer (c ₀ ) around the inner wall of the upper bucket bucket, a raw material layer (y ₀ ) at the lower side of the bucket center, and the bucket center A raw material layer (x ₀ ) is formed on the upper side of each.
The hot metal using the vertical melting furnace according to any one of claims 1 to 3 , wherein the raw fuel in the bucket is charged into the furnace by opening the gate at the bottom of the bucket at the top of the furnace. Manufacturing method. Raw fuel is charged into a bucket having a gate that can be opened at the bottom, and the raw fuel layer in the bucket has at least an iron-based scrap layer (s ₀ ), a coke layer (c ₀ ), and a CaO content of 5 mass. % Of the raw material layer (x ₀ ) composed of the raw material, and each layer is formed in the following form (1) or (2),
(1) An iron-based scrap layer (s ₀ ) is formed at the lowermost layer, a coke layer (c ₀ ) is formed around the inner wall of the upper bucket bucket, and a raw material layer (x ₀ ) is formed at the center of the bucket.
(2) An iron-based scrap layer (s ₀ ) is formed in the lowermost layer, a coke layer (c ₀ ) is formed in the upper layer, and a raw material layer (x ₀ ) is formed in the central portion of the upper bucket.
By opening the gate at the bottom of the bucket at the top of the furnace, the raw fuel in the bucket is charged into the furnace, and then a raw material having a SiO ₂ content of 95 mass% or more is charged from the charging chute provided at the top of the furnace. In the raw fuel layer formed by charging the raw fuel from the top of the furnace by being charged into the reactor, each layer is formed in the form of (i) or (iii). The manufacturing method of the hot metal using the vertical melting furnace in any one of 1-3 .

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