JPH11106821A - Method for producing agglomerate raw material for steelmaking - Google Patents

Abstract

(57) [Problem] To produce at low cost an agglomerated raw material having excellent performance as a raw material for steelmaking from a raw material partially or wholly as a granular material. SOLUTION: A part or the whole is composed of a granular material, and at least a part thereof is CaO, Ca (OH) ₂ , MgO,
Using a raw material containing at least one selected from Mg (OH) ₂ , a pile of the raw material or a packed layer in an arbitrary space is formed, and carbon dioxide gas is added to the pile or the packed layer. A carbonation reaction is caused in the presence, and the raw material is consolidated and agglomerated using CaCO ₃ and / or MgCO ₃ generated in the carbonation reaction as a binder, and used as an iron source and / or an auxiliary material for steelmaking. Obtain agglomerate raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an agglomerate raw material which is obtained by agglomerating a raw material partially or wholly as a granular material and which is used as an iron source and / or an auxiliary material for steelmaking. More particularly, the present invention relates to a new method for producing a raw material for steelmaking, which can realize, at low cost, slag generated in an iron and steel manufacturing process, in particular, fine powder slag, which was conventionally difficult to use.

[0002]

2. Description of the Related Art In the operation of a converter, iron sources such as scrap iron and cold iron are used as main raw materials other than hot metal, and various sources such as CaO sources, MgO sources, mill scale, and carbon materials are used as slag-forming agents and coolants. The auxiliary raw material is charged into the furnace, and blowing is performed.

[0003]

However, when such an iron source or an auxiliary material is in the form of powder or granules or has a large proportion of granules, it is blown when introduced into a furnace. As it rises, it cannot be put into the furnace as it is. For this reason, when a powdery iron source (for example, iron-containing dust, magnetic separation dust, etc.) or an auxiliary material (for example, quicklime powder, limestone powder, MgO powder, coke powder, etc.) is used in a converter, these should be used appropriately. It is necessary to form a briquette using a binder, or to agglomerate it by a method such as granulation, which has caused a problem in terms of processing cost.

By the way, various slags generated in a steelmaking process such as converter slag contain a large amount of components that can be used as iron sources and auxiliary materials for steelmaking in converters and the like. It is desired to use it effectively as a raw material. However, some slags have a property of powdering due to transformation expansion of γ-dicalcium silicate generated upon cooling and expansion caused by hydration of free CaO. For these reasons, they cannot be used as raw materials for steelmaking. In addition, when the components in the slag are used as an iron source or an auxiliary material of a converter, it is preferable to perform separation (for example, recovery of bullion) to increase the purity of each component. It is necessary to pulverize slag, and slag thus pulverized cannot be used as a raw material for steelmaking as it is for the same reason.

[0005] Accordingly, an object of the present invention is to solve such a conventional problem and reduce the cost of agglomerating raw materials having excellent performance as raw materials for steelmaking from raw materials partially or wholly as granules. It is an object of the present invention to provide a method for producing a compacted raw material for steelmaking that can be produced. Another object of the present invention is to provide a method for producing the above-mentioned agglomerate raw material for steelmaking, which can use powdered slag or finely pulverized slag as a material.

[0006]

Means for Solving the Problems The present inventors have conducted experiments and studies to solve the above-mentioned problems, and as a result, have obtained the following knowledge. (1) Carbonation and solidification of a raw material made of a granular material that can be an iron source or an auxiliary raw material for steelmaking, that is, a carbonation reaction occurs in the presence of carbon dioxide gas in CaO or MgO contained in the raw material, The resulting CaCO ₃ and Mg
By consolidating CO ₃ as a binder, it is possible to agglomerate powder and granules without performing briquetting and granulation, which require processing costs as in the past, and agglomerates (preferable as raw materials for steelmaking) Lumps) are obtained. This agglomerate material for steelmaking uses a binder (CaC) using CaO and MgO, which are almost indispensable auxiliary material components in converter operation and the like.
O _3, MgCO ₃₎ to generate, which was consolidated powder and granular material, hence auxiliary material itself also serves as a binder, in particular an extremely large economic effect from this point.

(2) In addition to such cost advantages, the above-mentioned agglomerates in which the granules solidify using CaCO ₃ or MgCO ₃ as a binder are particularly excellent as raw materials for steelmaking. Has performance. That is, this agglomerate has sufficient strength at room temperature or at a certain high temperature,
0 when placed in a high temperature exceeding ℃ is CaCO ₃ or MgCO ₃ as a binder and砕化thermally decomposed, CaCO
₃ and MgCO ₃ release CO ₂ to become CaO or MgO. Therefore, the agglomerate put into the furnace does not immediately break down, but reaches the slag surface (or its vicinity; the same applies hereinafter) as a lump, and is not thermally decomposed until it is heated to a high temperature in the slag surface or slag.・ Crushed and uniformly dispersed on the slag surface and inside the slag. For this reason, agglomerates
In the initial stage after charging, it does not crush (pulverize) before reaching the slag surface, and does not cause scattering due to this crushing, while high temperature occurs on the slag surface or in the slag that arrives in a lump. The slag is rapidly crushed and dispersed by being heated, and is used as an iron source or an auxiliary material, so that a high yield and a high reaction efficiency can be obtained as a raw material for steelmaking.

(3) Generally, most of the slag generated in a steelmaking process such as converter slag contains a large amount of CaO and a relatively large amount of MgO. Therefore, this slag is a raw material. By using CaO or MgO contained in at least a part of the powder and granules and using the CaO or MgO contained therein for the above-described binder generation, it becomes possible to use the material as a raw material for steelmaking of powdered slag and finely pulverized slag,
It becomes possible to produce the agglomerate for steelmaking at a lower cost.

The present invention has been made based on such findings, and the features thereof are as follows. [1] A method for producing an agglomerate material used as an iron source and / or an auxiliary material for steelmaking, wherein a part or the whole is formed of a granular material and at least a part of CaO, Ca (O (O)
H) ₂ , MgO, using a raw material containing at least one selected from Mg (OH) ₂ , forming a pile of the raw material or a filling layer in an arbitrary space, and forming the pile or A carbonation reaction is caused in the packed bed in the presence of carbon dioxide gas, and CaCO ₃ and / or MgC
Agglomerating raw material for steel making characterized by solidifying and agglomerating the raw material using O ₃ (including the case where MgCO ₃ is present as a hydrate, hydroxide salt or double salt) as a binder Manufacturing method.

[2] In the production method according to the above [1], the raw material is slag, a raw material to be an iron source, a carbon material, dust collection, slag to be a CaO and / or Ca (OH) ₂ source. Other raw materials, MgO and / or Mg
(OH) _{2 A} method for producing an agglomerate material for steelmaking, comprising at least one material selected from material materials other than slag to be a source. [3] In the production method according to the above [1] or [2], at least a part of the raw material contains CaO and / or Ca
A method for producing an agglomerate raw material for steelmaking, which is a slag containing (OH) ₂ .

[4] In the method of the above-mentioned [1] or [2], at least a part of the raw material contains CaO and / or Ca (OH) ₂ and MgO and / or Mg
A method for producing an agglomerate raw material for steelmaking, which is a slag containing (OH) ₂ . [5] In the method according to any one of the above [1] to [4], carbon dioxide gas or a carbon dioxide-containing gas is blown into the pile or the packed bed of the raw material, or the pile or the packed bed is filled with carbon dioxide or carbon dioxide. A method for producing an agglomerate raw material for steelmaking, wherein the raw material is placed in a gas-containing gas atmosphere.

[6] In the method of any one of the above [1] to [5], a carbon dioxide gas or a carbon dioxide-containing gas is passed through water to saturate H ₂ O, and thereafter, a pile of raw materials is piled up. Alternatively, a method for producing an agglomerate raw material for steelmaking, wherein the raw material is supplied to a packed bed for carbonation treatment. [7] In the production method according to any one of the above [1] to [6], a pile or a packed bed of raw materials consolidated by a carbonation reaction is crushed to obtain an agglomerate of a desired size. A method for producing a compacted raw material for steelmaking.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The method of the present invention for producing an agglomerate raw material for steelmaking is characterized in that a part or the whole is composed of a granular material (a granular and / or coarse-grained substance; the same applies hereinafter) and at least a part of CaO , Ca (OH) ₂ , MgO, Mg (OH) ₂
A carbonation reaction in the presence of carbon dioxide gas on a raw material material containing at least one selected from the group consisting of CaCO ₃ and / or MgCO ₃ (where M
This includes cases where gCO ₃ is present as a hydrate, hydroxide salt or double salt. The same shall apply hereinafter) as a binder to consolidate and agglomerate (agglomerate) the raw materials.

The reaction between CaO and CO ₂ , that is, consolidation using CaCO ₃ generated by a carbonation reaction, is a technique that has been known for a long time. When placed under a gas atmosphere, the CaCO ₃ produced by the following reaction formula, resulting in consolidation phenomenon between the particles of the CaCO ₃ as the binder. CaO + CO ₂ → CaCO ₃

Conventionally, as a technique utilizing such a carbonation reaction, for example, a method of producing a hardened product such as a building material using a kneaded product of steelmaking crushed slag and water (for example, Japanese Unexamined Patent Publication No. -74559) and a method for producing unfired pellets (for example, see JP-A-57-92143 and JP-A-58-92143).
-48642, JP-A-58-133334) and the like. However, these prior arts are all intended only to produce a hardened product or a non-fired pellet having a required strength in a short time, and a raw material including a granular material is solidified by a carbonation reaction. Nothing is shown about obtaining an agglomerate for a steelmaking raw material by sintering or that the agglomerate has particularly excellent performance as a steelmaking raw material.

[0016] Further, with respect to the powdery or granular material containing MgO, if this is placed in a carbon dioxide gas atmosphere, MgC can be obtained by a carbonation reaction.
O ₃ is generated, and a consolidation phenomenon occurs between the particles using the MgCO ₃ as a binder. MgCO ₃ generated by the carbonation reaction of MgO can be used in various forms such as anhydrate, hydrate (eg, dihydrate, trihydrate, pentahydrate, etc.) and hydroxide salt (basic magnesium carbonate). Although, for example, MgCO ₃
Is produced by the following reaction formula. _{MgO + CO 2 + 3H 2 O} → MgCO 3 · 3H 2 O

The steelmaking agglomerate obtained by the production method of the present invention comprises binders CaCO ₃ and MgCO ₃ ,
Almost essential secondary material components in the converter operation as CaO source and MgO source (the former is a slag-making agent, a refining agent, and the latter is a slag control agent). These CaCO ₃ and MgCO ₃
Is injected into the furnace and heated by the slag,
₂ is released to form CaO and MgO, which are used as auxiliary raw materials. Therefore, the agglomerate for steelmaking obtained by the production method of the present invention has a great feature that the auxiliary material itself also functions as a binder, and can be said to be an extremely economical agglomerate.

Hereinafter, the method for producing the agglomerate material for steelmaking of the present invention will be specifically described. FIG. 1 shows an example of a production flow according to the method of the present invention. The raw material (starting raw material) used in the production method of the present invention is a substance that can be an iron source or an auxiliary raw material for steelmaking, and is partially or entirely composed of a granular material and at least partially composed of CaO, Ca
1 selected from (OH) ₂ , MgO and Mg (OH) ₂
There are no restrictions on the type and composition of the raw material as long as it is a raw material containing more than seeds, and various types of slag (for example, blast furnace slag, steelmaking slag such as decarburized slag and dephosphorized slag, ore reduction slag, etc.) , Raw materials to be used as iron sources (for example, ingots recovered from slag), carbon materials (for example, coke powder, anthracite, etc.), and various types of dust (for example, converter dust, blast furnace dust, etc.) ), CaO and / or Ca (OH) ₂ source, MgO and / or Mg (O
H) A raw material consisting of one or more of raw materials other than slag to be a source of ₂ (eg, limestone, quicklime, slaked lime, dolomite, magnesia flicker, etc.) can be used.

However, CaO, Ca (OH) ₂ ,
When a raw material containing neither MgO nor Mg (OH) ₂ or a raw material whose content is insufficient to consolidate the raw material by a carbonation reaction is used as a main raw material, , CaO, Ca (OH) ₂ , M
A raw material of at least one selected from gO and Mg (OH) ₂ or a raw material containing one or more of these (for example, quicklime, slaked lime, magnesia clinker, slag, etc.) is mixed and mixed into the raw material. CaO, Ca (O
H) ₂ , MgO, and Mg (OH) ₂ are adjusted in advance so as to contain an appropriate amount of at least one selected from the group. Further, the raw material may be composed of only one or more raw materials selected from CaO, Ca (OH) ₂ , MgO, and Mg (OH) ₂ .

The raw material to be used may have any particle size composition as long as a part or all of the material is a powder. However, the raw materials to be fed into a steelmaking furnace such as a converter as an iron source or auxiliary raw materials generally depend on the specific gravity thereof, but are generally powdered materials (for example, having a sieve particle size of −).
When the content of powder (about 6 mm) is 20% by weight or more, the rate of scattering by blowing up is remarkably increased, so that it is difficult to use the powder as it is as a raw material for the furnace. The point is that the raw material containing the granules is used as a raw material for agglomeration for steelmaking. Therefore, it can be said that the present invention is particularly suitable for agglomerating a raw material containing such a ratio of powder and granules.

In the carbonized solidified raw material obtained by the present invention, as the particle size of the raw material to be used is smaller, the raw material particles can be brought into closer contact with each other and consolidated.
As a result, the bonding between the particles is enhanced, and the strength of the lump can be ensured. Therefore, from this point as well, it is preferable that the raw material material is substantially composed of a granular material or a material containing a relatively large amount of the granular material. Specifically, as the raw material, it is particularly preferable to use a raw material having a particle size distribution in which the size under the sieve of 20 mm or less is 100% by weight and the size of the particle under the sieve of 10 mm or less is 20% by weight or more. Here, the particle size under the sieve of 20 mm or less refers to the particle size of the raw material passing through a sieve having a sieve of 20 mm, and the particle size of 10 mm or less under the sieve refers to the particle size of the raw material passing through a sieve having a sieve of 10 mm. The sieve to be used may be either a mesh sieve or a grizzly.

When the raw material is slag, the slag having the above-mentioned particle size distribution includes fine powder slag powdered by expansion caused by hydration (digestion) of free CaO present in the slag, and slag of slag. Γ-dicalcium silicate (2CaO.Si) generated during cooling
O ₂₎ pulverized slag were powdered by transformation expansion of the slag was pulverized by grinding treatment with bullion removal process, it contains slag etc., interest member of the殆as steelmaking raw material for these slag as it Therefore, such slugs can be suitably used in the present invention.

In general, slag generated in the steel making process contains a considerable amount (usually 20% to 60% by weight) of Ca.
O or Ca (OH) ₂ whose CaO has been changed, and most slags have a certain amount of MgO together with CaO or Mg (O) whose MgO has been changed.
H) ₂ is included. Therefore, it is particularly preferable to use slag generated in the steel manufacturing process for part or all of the raw material. At that time, it is more preferable to use the powdered slag or the finely pulverized slag as described above, since these can be used as materials.

The slag used as a raw material includes blast furnace slag such as blast furnace slow cooling slag, blast furnace granulated slag, etc., desiliconized slag, desulfurized slag, dephosphorized slag generated in processes such as pretreatment, converter and casting. Examples include steelmaking slag such as slag, decarburized slag, and cast slag, ore reduction slag, electric furnace slag, and the like, but are not limited thereto. These slags may be used as a mixture of two or more kinds.

Among these slags, examples of typical slag compositions (% is "% by weight") are shown below. (1) Decarburized slag ... T. Fe: 17.5%, CaO: 4
_{6.2%, SiO 2: 11.7%} , Al 2 O 3: 1.4
%, MgO: 8.3%, MnO: 6.2%, P: 0.7
6%, S: 0.04% (2) Dephosphorized slag ... Fe: 5.8%, CaO: 5
_{4.9%, SiO 2: 18.4%} , Al 2 O 3: 2.8
%, MgO: 2.3%, MnO: 1.9%, P: 2.8
%, S: 0.03%

(3) Desulfurized slag: T. Fe: 10.5
%, CaO: 50.3%, SiO 2: 10.0%, Al 2
O ₃ : 5.4%, MgO: 1.1%, MnO: 0.4
%, P: 0.13%, S: 1.8% (4) Desiliconized slag ... Fe: 10.5%, CaO: 1
_{3.6%, SiO 2: 43.7%} , Al 2 O 3: 3.8
%, MgO: 0.4%, MnO: 15.8%, P: 0.
10%, S: 0.19% (5) Granulated blast furnace slag: FeO: 0.3%, CaO: 4
2.0%, SiO ₂ : 33.8%, MnO: 0.3%,
MgO: 6.7%, Al ₂ O ₃ : 14.4%

Of the slag generated in the steel making process, dephosphorized slag has a high P content, and desiliconized slag has a high MnO content. However, in the present invention, these slags can be used as a raw material without any problem.

In the slag generated in the steel making process, some or all of the CaO and MgO contained therein are changed to Ca (OH) ₂ or Mg (OH) ₂ due to temporal absorption of moisture or other causes. If there is, but without any problem as a slag to be used for the material feedstock in the present invention method, as described above, the present invention method these Ca (OH) ₂ or Mg (O
H) _{2 is} also CaCO ₃ , MgCO ₃
It changes to ₃ to produce a binder, and a steelmaking agglomerate is obtained.

When slag generated in the steel manufacturing process is used for a part or all of the raw material, the slag is subjected to slag removal processing as necessary. In this slag removal process, the main slag (granular iron) is used. Minutes are removed. Generally, the slag component and the metal in the slag are mixed in a state in which they are closely entangled. Therefore, when performing the metal ingot removal processing, the slag is performed in a state in which the slag is in the form of powder and / or coarse particles. After the slag is crushed by a crusher or the like to a particle size of mm order or less (for example, 5 mm or less), a slag removal treatment is performed. However, the slag only needs to have a particle size capable of recovering and removing the slag at a certain recovery rate.Therefore, if the slag can be removed to a certain degree even if it is relatively coarse-grained due to the properties of the slag, etc. The slag may be pulverized to a particle size capable of reducing the slag. In addition, some slags are carried in a state of natural powdering or granulation to a particle size capable of removing metal, and such slags may not require the above-described pulverizing treatment. . Ingot removal as described above is appropriately performed as necessary according to the ingot content of the slag.

Usually, the metal removal treatment is performed by magnetic separation (a method of removing iron particles in slag by a magnet) using a magnetic separator or the like, but is not necessarily limited to this. A specific gravity selection method such as a wind power separation utilizing a specific gravity difference between the slag component and the slag component can also be used. By this metal removal processing, a main metal component in the slag is removed.

The raw material thus pre-processed as required is piled up or filled in an arbitrary space for carbonation solidification. Here, when stacking the raw material, the pile may be piled up.However, in order to allow the injected carbon dioxide gas to sufficiently flow through the entire pile, and to prevent the raw material from being scattered or flowing out due to rainwater, the pile should be stacked. It is preferable to cover with a sheet or the like.

For stacking or filling the raw materials,
For example, a pit whose three sides are surrounded by a partition wall, a formwork or a container whose four sides are surrounded by a partition wall, or the like can be used. In the case where the raw material is piled or filled in the pits, it is preferable that the pile or the filled layer is covered with a sheet or the like as in the case of the above-mentioned unstacking. Also in the case of using a mold or a container, it is preferable to cover the filling layer of the raw material with a sheet or to provide a lid. FIG. 1 shows the form 1
2 shows a state in which a filling layer A is formed inside.

The stacking or filling amount of the raw material is not particularly limited, and may be, for example, a stacking or filling amount of several to several hundred tons, or a smaller stacking or filling amount. The amount is arbitrary. However, even if the pile amount or filling amount of the raw material is large, agglomerates can be easily cut out by crushing the pile or the packed bed after carbonation with heavy equipment, etc. Since agglomerates having a predetermined particle size can be obtained by passing the mixture, it is preferable that the pile amount or the filling amount of the raw material is somewhat large from the viewpoint of productivity. Specifically, the scale is set to 10 t or more. Is preferred.

Although the density of the agglomerate to be produced depends on the pile of the raw material or the bulk density (consolidation density) of the packed bed, in order to secure a predetermined handling strength as the agglomerate for steelmaking. Is preferably a certain high density, and therefore it is preferable to compact the pile or the packed bed.

The compaction of the pile or the packed bed of the raw material can be carried out by a method of compacting the pile or the packed bed from above by a heavy machine, or a method of compacting the pile or the packed bed by applying vibration. By adjusting the degree of compaction when performing these, the pile density or the bulk density of the packed bed is adjusted. However, if excessive compaction is performed, the flow of carbon dioxide gas becomes poor, so that carbonation of the raw material material tends to be insufficient. In general, the porosity of the pile or the packed layer is particularly preferably about 13 to 15% from the viewpoint of the strength of the produced agglomerate and the gas permeability during the production.

As a specific method of compaction, for example, when compaction is performed on a pile or a packed layer in a pit, a mold or a container as described above, a target is placed inside the pit, the mold or the container. A weighing line indicating the volume to be used is displayed, and after the raw materials with known weights are put in the inside thereof, compaction is performed until the pile or the upper surface of the packed layer reaches the height of the weighing line.

After the adjustment of the bulk specific gravity of the pile or the packed bed of the raw material as described above is completed, a carbonation reaction is caused in the pile or the packed bed in the presence of carbon dioxide gas, and the CaCO ₃ generated thereby is produced. Alternatively, the raw material is carbonated (consolidated) using CaCO ₃ and MgCO ₃ as binders. Specifically, a carbon dioxide gas or a carbon dioxide-containing gas is blown into a pile or a packed layer of the raw material, or the pile or the packed layer is placed under a carbon dioxide or a carbon dioxide-containing gas atmosphere, and the carbonized solidification of the raw material is performed. Is carried out.

There is no particular limitation on the method of blowing carbon dioxide gas or carbon dioxide-containing gas into the pile or the packed bed.
Gas blowing means is provided at the bottom of the pile or packed bed,
It is most effective to blow gas through this gas blowing means. Specifically, gas supply pipes or hoses are arranged at an appropriate arrangement density at the bottom of the pile or the packed layer (when using pits, formwork or containers, etc., their floors). A carbon dioxide gas or a carbon dioxide-containing gas can be blown out from a gas blowing hole provided at an appropriate pitch (for example, a pitch of 300 mm to 400 mm) in a pipe or a hose.

As a method of placing the pile or the packed layer in a carbon dioxide gas or a carbon dioxide-containing gas atmosphere, the pile or the packed layer is placed in an airtight space (including a container or the like).
A method of supplying a carbon dioxide gas or a carbon dioxide-containing gas into this space in an arbitrary mode can be adopted. As the carbon dioxide-containing gas used, for example, a lime burning plant exhaust gas (usually, CO ₂ : about 25%) or a heating furnace exhaust gas (usually, CO ₂ : about 6.5%) discharged in an integrated steel mill is used. Suitable, but not limited to. In addition, if the concentration of carbon dioxide in the carbon dioxide-containing gas is too low, there is a problem that the processing efficiency is reduced, but other problems are not particularly significant. Therefore, the concentration of carbon dioxide is not particularly limited, but is preferably 3% or more for efficient processing.

There is no particular limitation on the amount of carbon dioxide gas or gas containing carbon dioxide gas to be blown, and gas may be blown to such an extent that a pile of raw materials or a packed bed does not flow. Is 0.004 to 0.5 m ³ /
It is sufficient that a gas blowing amount of about min · t can be secured.
Also, there is no special restriction on the gas blowing time (carbonation time), but as a guide, the time when the blowing amount of carbon dioxide gas (CO ₂ ) becomes 3% or more of the weight of the raw material, that is,
In terms of gas amount, it is preferable to perform gas blowing until carbon dioxide (CO ₂ ) of 15 m ³ or more per 1 t of material is supplied.

The carbon dioxide gas or carbon dioxide-containing gas blown into the pile or the packed bed of the raw materials may be at room temperature.
If the temperature of the gas is higher than room temperature, it is advantageous because the reactivity increases accordingly. However, if the gas temperature is excessively high, Ca
CO ₃ is decomposed into CaO and CO ₂ , and MgCO ₃
Since it is decomposed into O and CO ₂ , it is necessary to use a gas having a temperature that does not cause such decomposition even when a high-temperature gas is used.

In addition, water is required to carbonize the raw material using the reaction of CaO, MgO, etc. with carbon dioxide gas, and water is required. The water content in the raw material immediately before the start of the carbonation treatment is 3 to 10%. % Is preferable. This is C in water
This is because the carbonation reaction is promoted by dissolving aO, MgO and carbon dioxide gas. Therefore, if the water content of the raw material constituting the pile or the packed bed is too low, water can be added to the raw material at an appropriate stage to increase the water content of the raw material. Moreover, H ₂ blown once into water carbon dioxide or carbon dioxide-containing gas
By saturating O and then blowing it into the pile or packed bed, it is possible to prevent the raw material from drying and to promote the carbonation reaction.

By supplying carbon dioxide or a carbon dioxide-containing gas into the pile or the packed bed of the raw materials as described above, CaO (or Ca (O
H) ₂ ), the reaction of MgO (or Mg (OH) ₂ ) with carbon dioxide produces CaCO ₃ and MgCO ₃ ,
ACO ₃ or taken CaCO ₃ and MgCO ₃ are the binder particles of the material feedstock closely consolidated.

After the completion of carbonation solidification, if necessary, the pile or packed bed is crushed to an appropriate size by a heavy machine or the like, and agglomerates are cut out. Adjustment is performed to obtain a steelmaking agglomerate having a desired particle size. The agglomerate under the sieve is reused as a raw material. The particle size of the agglomerate raw material for steelmaking obtained by the production method of the present invention can be arbitrarily selected depending on the size of the packed bed at the time of production, the degree of crushing treatment and sieving, and the like. A particle size of about -80 mm is appropriate. The sieve to be used may be either a mesh sieve or a grizzly.

As described above, MgO or Mg (O
MgCO ₃ is anhydrate produced by carbonation reaction of H) _2,
Hydrates, hydroxide salts, etc., which take various forms. MgCO ₃ contained as a binder in the steelmaking agglomerate obtained by the method of the present invention may be any of these forms of MgCO 3. ₃ is acceptable. For example, as a hydrate of _{MgCO 3, MgCO 3 · 2H 2} O, MgCO 3 · 3H
₂ O, MgCO ₃ .5H ₂ O, etc., and hydroxide salts (basic magnesium carbonate) such as MgCO ₃ .Mg
_{(OH) 2 · 3H 2 O} , 4MgCO 3 · Mg (OH) 2 · 4
_{H 2 O, 4MgCO 3 · Mg} (OH) 2 · 5H 2 O, 4Mg
CO ₃ .Mg (OH) ₂ .8H ₂ O and the like. Further, M
GCO ₃ may form a variety of double salt in combination with other salts, may be MgCO ₃ present in the form of such a double salt.

The agglomerate raw material for steelmaking obtained by the above-described production method of the present invention is a raw material partially or wholly composed of granules, which is tightly consolidated using CaCO ₃ and MgCO ₃ as binders. Therefore, it has sufficient strength as a raw material for furnace input. Further, as described above, the agglomerate obtained by the present invention has sufficient strength at room temperature or at a certain high temperature, but CaCO ₃ or MgCO ₃ becomes hot at a high temperature exceeding 900 ° C. Decompose and crush, C
CaO and MgO aCO ₃ and MgCO ₃ is to release the CO ₂
Becomes Therefore, the agglomerated raw material charged into the furnace does not immediately break up, but reaches the slag surface in a lump state, and is thermally decomposed and crushed only when heated to a high temperature in the slag surface or in the slag. It will be evenly dispersed inside. For this reason, the agglomerate raw material does not crush before reaching the slag surface in the initial stage after being charged, and does not scatter due to this crushing, while the slag surface or slag that has arrived as a mass Since the slag is rapidly crushed and dispersed by heating with high-temperature slag and is used as an iron source or an auxiliary material, it has a great feature in terms of performance that a high yield and a high reaction efficiency can be obtained as a steelmaking raw material.

[0047]

EXAMPLES Example 1 Steelmaking slag powder having a particle size of 3 mm or less and 100% by weight (T.Fe: 1.6% by weight, CaO: 35.3% by weight)
%, SiO ₂ : 19.2 wt%, Al ₂ O ₃ : 13.6 w
t%, MgO: 27.3 wt%) with a width of 7 m and a depth of 10 m.
After piled up to a height of 1.5 m in the pit and properly compacted, the pit was sealed and the carbon dioxide gas supply amount was 70 Nm ³ /
The slag was blown at a rate of hr for 5 days to solidify the slag with carbonic acid. The carbonated and solidified slag was roughly crushed by a heavy machine to give an agglomerate having a particle size of 80 mm or less. At this time, when the particle size distribution of the entire amount of the slag carbonized was measured, the particle size was 8 mm.
The proportion of the following was about 13%. Moreover, the crushing strength of the crushed agglomerate was 160 kg / piece, and had a strength usable as a raw material for a steelmaking furnace. As a result of actually feeding this agglomerate to the converter as an auxiliary raw material, the amount of scattering by blow-up (the amount of dust collected by a dust collector) was small, and the agglomerate could be used as a raw material for a steelmaking furnace without any problem.

[Example 2] Among the magnetic separation chips (metals) collected from the dephosphorized slag, magnetic separation chips having a particle size of 8 mm or less and slaked lime, which cannot be used as a raw material for the converter as they are, were uniformly mixed with a tire shovel. (The ratio of slaked lime in the mixture: 15 wt%) was piled up in a pit having a width of 4 m and a depth of 6 m to a height of 1.5 m and compacted appropriately, then the pit was sealed, and a carbon dioxide gas supply rate of 50 Nm ³ / The raw material was carbonized and solidified by blowing for 3 days at a rate of hr. The carbonized solidified raw material was roughly crushed by a heavy machine to obtain an agglomerate having a particle size of 80 mm or less. At this point, the particle size distribution of the entire amount of the carbonized solidified raw material was measured.
%Met. The crushing strength of the agglomerate after crushing is 110
kg / piece, and had a strength that could be used as a raw material for steelmaking furnaces. Actually, the agglomerate was put into a converter type dephosphorization furnace as an iron source, and as a result, the amount of scattering by blow-up (the amount of dust collected by a dust collector) was small, and it could be used as a raw material for a steelmaking furnace without any problem.

Example 3 Anthracite having a particle size of 15 mm or less and powdered slaked lime were uniformly mixed, and this mixture (the ratio of slaked lime in the mixture: 10 wt%) was placed in a pit having a width of 7 m × 10 m and a height of 1 m. Then, the pit was sealed and carbon dioxide gas was blown in at a supply rate of 50 Nm ³ / hr for 5 days to carbonize and solidify the raw material. The carbonized solidified raw material is roughly crushed by a heavy machine, and the particle size is 80 mm.
The following agglomerates were obtained. At this time, the particle size distribution of the entire amount of the carbonated solidified material was measured, and the ratio of those having a particle size of 8 mm or less was about 8%. The crushing strength of the agglomerate after crushing was 90 kg / piece, and had a strength usable as a raw material for a steelmaking furnace. As a result of actually feeding this agglomerate to the converter as an auxiliary raw material, the amount of scattering by blow-up (the amount of dust collected by a dust collector) was small, and the agglomerate could be used as a raw material for a steelmaking furnace without any problem.

[0050]

As described above, according to the production method of the present invention, the agglomerate raw material for steel making which exhibits excellent performance is reduced by using the powdery material which can be used as an iron source or auxiliary material for steel making as a raw material. Mass production can be at cost. In particular, since powdered slag and finely pulverized slag, which were conventionally difficult to use as raw materials for steelmaking in terms of processing costs, can be used at low cost for steelmaking, slag generated in the steelmaking process can be effectively used. But it is a very useful invention.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a production flow of the method of the present invention.

[Explanation of symbols]

 1: Mold, A: Filled layer

Claims (7)

[Claims] 1. A method for producing an agglomerate raw material used as an iron source and / or an auxiliary raw material for steelmaking, wherein a part or all of the raw material is a granular material and at least a part of Ca is used.
Using a raw material containing at least one selected from O, Ca (OH) ₂ , MgO, and Mg (OH) ₂ , forming a pile by the raw material or a filling layer in an arbitrary space,
A carbonation reaction is caused in the pile or packed bed in the presence of carbon dioxide gas, and CaCO ₃ and / or
Alternatively, agglomeration for steelmaking characterized by solidifying and agglomerating the raw material using MgCO ₃ (including the case where MgCO ₃ is present as a hydrate, hydroxide salt or double salt) as a binder. Raw material production method. 2. The raw material is slag, a raw material to be an iron source, a carbon material, dust collection dust, CaO and / or Ca
(OH) ₂ Raw material other than slag to be a source, MgO
The method for producing an agglomerate raw material for steelmaking according to claim 1, further comprising at least one selected from raw materials other than slag to be a Mg (OH) ₂ source. 3. The production of an agglomerate material for steelmaking according to claim 1, wherein at least a part of the material material is a slag containing CaO and / or Ca (OH) ₂ in its component. Method. 4. At least a part of the raw material contains CaO and / or Ca (OH) ₂ and MgO and / or
3. The method for producing an agglomerate raw material for steelmaking according to claim 1, wherein the slag contains Mg (OH) _{2. 4} . 5. The method according to claim 1, wherein a carbon dioxide gas or a carbon dioxide-containing gas is blown into the pile or the packed layer of the raw material, or the pile or the packed layer is placed in a carbon dioxide or a carbon dioxide-containing gas atmosphere. 1, 2, 3 or 4
The method for producing agglomerated raw materials for steelmaking according to the above. 6. A method in which a carbon dioxide gas or a carbon dioxide-containing gas is passed through water to saturate H ₂ O, and then supplied to a pile or a packed bed of raw materials for carbonation treatment. The method for producing an agglomerate raw material for steelmaking according to claim 1, 2, 3, 4, or 5. 7. The agglomerate having a desired size is obtained by crushing a pile or a packed bed of raw materials consolidated by a carbonation reaction. Or 6
The method for producing agglomerated raw materials for steelmaking according to the above.