JP2005097665A - Reduced metal raw material agglomerate and its producing method, and method for producing reduced metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a reduced iron briquette at a low cost with which in the case of producing the reduced iron by heating and reducing the reduced iron raw material briquette by using a large quantity of fine powdery raw materials, such as electric furnace dust, with a reducing furnace, such as a rotary hearth furnace, the ordinary binder can be used and the mixture of the raw material is easily performed without needing high pressing force in a briquette forming machine and also, the dry of the briquette. <P>SOLUTION: Into the fine powdery raw material A, such as the electric furnace dust, the binder C and if necessary, moisture D are added/mixed to make binder-added slurry A1. After drying this slurry A1, coarse dried raw material B, such as coke powder, is added/mixed to make a dry-mixed material E. Then, this dry-mixed material E is compression-molded to make the reduced iron raw material briquette (reduced metal raw material briquette) F. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention belongs to the field of technology for producing a reduced metal by reducing a dry granulated product containing a powdered metal oxide and a powdered carbonaceous reducing material in a reduction furnace such as a rotary hearth furnace. The present invention relates to a technique for producing a dry granulated product using a large amount of raw materials.

(Prior art 1)
A typical production process for producing reduced iron pellets (hereinafter also simply referred to as “reduced iron”) as the reduced metal is shown in FIG. 2 (see, for example, Patent Documents 1 and 2).

  [Mixing step]: As shown in the figure, first, coal B and binder C as carbonaceous reducing materials are added to iron ore powder A as a powdered metal oxide raw material, and water D is further added by about several mass%. Then, they are mixed with the mixer 3 to obtain a raw mixture E.

  [Granulation step]: This raw mixture is granulated by a pelletizer 4 as a granulator to produce raw pellets F as a raw granulated product. Instead of granulating with pelletizer 4 to form raw pellet F, raw mixture E having a moisture content of 3 to 10% by mass is compression-molded at a relatively low pressure by briquette molding machine 4 and raw briquette having a high moisture content. F is also performed.

  [Drying step]: Next, the raw pellet (or raw briquette) F is dried in the dryer 5 to obtain a dry pellet (or dry briquette) G as a dry granulated product.

  [Reduction step]: The dry pellets (or dry briquettes) G are charged into a rotary hearth furnace 6 as a reduction furnace, and heated to reduce, so that high production without causing bursting in the furnace. And reduced iron H as a reduced metal can be obtained with high yield.

  However, as a powdered metal oxide raw material, in general, instead of or in addition to iron ore powder A having an average particle size of several tens to several hundreds of μm, an average particle size of submicron to several μm such as electric furnace dust is very fine. A fine powder raw material of a particle size may be used. When a large amount of such a fine powder raw material is used, the adhesiveness of the mixture is remarkably increased when water is added and mixed in the mixing step, and the inside of the mixer 4 or from the mixer 4 to the granulator 5 is increased. In addition, there is a problem that powder compaction occurs in a feeder (not shown) for cutting out the raw mixture E, and the required power of the equipment becomes excessive, and in a severe case, mixing and cutting itself cannot be performed.

(Prior art 2)
On the other hand, as shown in FIG. 3, in the mixing step, cellulose fiber C is added as a binder to dry raw materials A and B, and moisture D is not added or only a small amount of about 1% by mass is added and mixed in mixer 3. In the granulation step, this is formed into a briquette F having a low moisture content having sufficient strength by compression molding at a relatively high pressure by the briquette molding machine 4 as a granulator in the granulation step. A method of charging the briquette F directly into the reduction furnace 6 without drying is disclosed (see Patent Document 3).

  In the above prior art 2, since the moisture is mixed in a substantially non-added state in the mixing step, the stickiness of the mixture E does not increase, and the problem as in the above prior art 1 does not occur. Moreover, since it is not necessary to dry the briquette F, the dryer for drying the granulated material F can be omitted, and the fuel for drying can also be reduced. However, since water is not substantially added to the mixture E, in order to form a high-strength briquette F, an extremely high pressure is required as compared with the prior art 1, and as a result, the segment of the briquetting machine 4 There is a problem that the wear of the resin becomes remarkable, the life of the segment is shortened, and the cost of maintenance is increased. Also, paper fluff or the like is suitable as the cellulose fiber used as the binder, but there is a problem that the cost is high and it is difficult to obtain it as compared with conventional binders such as molasses and wheat flour.

(Prior art 3)
Although not shown, using a coal such as bituminous coal containing at least 20% by mass of a volatile component as a carbonaceous reducing material, without adding a binder and moisture, the dry raw material and the coal are mixed to form a dry mixture, A method is disclosed in which the volatile matter generated from the coal is made to function as a binder by pressurizing it at a relatively low pressure at 427 ° C. or higher to form a briquette F, and the briquette F is charged into the reduction furnace 6 as it is. (See Patent Document 4).

In the prior art 3, since the mixing is performed without adding a binder and moisture in the mixing step, the adhesiveness of the mixture E does not increase, and the problem as in the prior art 1 does not occur. Moreover, since it is not necessary to dry the briquette F in addition to making a binder unnecessary, the dryer for drying the granulated material F can be omitted, and the fuel for drying can also be reduced. Furthermore, since it pressurizes in the state which heated and softened coal, it can shape | mold at a comparatively low pressure and can reduce the abrasion of the segment of a briquette molding machine. However, since the carbonaceous reducing material that can be used is restricted to predetermined bituminous coals, it may be difficult to obtain, and there is a problem that the equipment cost increases because heating is required during briquetting.
JP-A-11-279611 JP-A-11-193423 International Publication No. WO 01/94651 A1 Pamphlet Japanese National Patent Publication No. 11-511511

  Accordingly, the present invention provides a conventional binder for producing a reduced metal by heating and reducing a reduced metal raw material agglomerate produced by using a large amount of a fine powder raw material containing a metal oxide and / or a carbonaceous reducing material in a reduction furnace. To provide a low-cost method for producing a reduced metal raw material agglomerate that is easy to mix the raw materials, does not increase the pressure of the compression molding machine, and does not require drying of the agglomerates With the goal.

  In the first aspect of the present invention, a binder is added to a fine powder raw material containing a metal oxide and / or a carbonaceous reducing material, and this is mixed to form a slurry-like binder-added slurry, and the binder-added slurry is dried. Binder added dry raw material, obtained by adding and mixing a coarse powder dry raw material containing metal oxide and / or carbonaceous reducing material to this binder added dry raw material to form a dry mixture, and compression molding this dry mixture It is a reduced metal raw material agglomerate. In addition, when adding a binder to the said fine powder raw material, when the moisture content in the said fine powder raw material is insufficient, you may add a water | moisture content further.

  Invention of Claim 2 is a reduced metal raw material agglomerate of Claim 1 whose volume average diameter of the said fine powder raw material is less than 30 micrometers.

  The invention according to claim 3 is the reduced metal raw material agglomerate according to claim 1 or 2, wherein the water content of the binder-added slurry is 10% by mass or more.

  The invention according to claim 4 is the reduced metal raw material agglomerate according to any one of claims 1 to 3 having a water content of 3% by mass or less.

  In the invention according to claim 5, a binder is added to a fine powder material having a volume average diameter of less than 30 μm containing a metal oxide and / or a carbonaceous reducing material, and this is mixed to have a moisture content of 10% by mass or more in the external number. A binder addition step for producing a binder addition slurry, a raw material drying step for drying the binder addition slurry to a predetermined moisture content to obtain a binder addition dry raw material, and a metal oxide and / or carbonaceous material for the binder addition dry raw material. Add and mix coarse powder dry raw material containing a reducing material with a volume average diameter of 30 μm or more to form a dry mixture with a water content of 3% by mass or less, and compress this dry mixture to form a reduced metal raw material agglomerate. It is a manufacturing method of the reduced metal raw material agglomerate characterized by including the compression molding process.

In the invention according to claim 6, a binder is added to a fine powder raw material having a volume average diameter of less than 30 μm containing a metal oxide and / or a carbonaceous reducing material, and this is mixed to have a moisture content of 10% by mass or more in the external number. A binder addition step for forming a binder addition slurry, a raw material drying step for drying the binder addition slurry to a predetermined moisture content to obtain a binder addition dry raw material, and a reduced metal raw material lump by compression molding the binder addition dry raw material It is a manufacturing method of the reduced metal raw material agglomerate characterized by including the compression molding process with the product.

  In the invention according to claim 7, a binder is added to a fine powder material having a volume average diameter of less than 30 μm containing a metal oxide and / or a carbonaceous reducing material, and this is mixed to have a moisture content of 10% by mass or more in the external number. A binder addition step for producing a binder addition slurry, a raw material drying step for drying the binder addition slurry to a predetermined moisture content to obtain a binder addition dry raw material, and a metal oxide and / or carbonaceous material for the binder addition dry raw material. Addition / mixing step of adding / mixing coarse powder dry raw material containing a reducing material and having a volume average diameter of 30 μm or more into a dry mixture having a water content of 3% by mass or less, and compression-molding the dry mixture to reduce metal raw material A method for producing a reduced metal, comprising: a compression molding step for forming an agglomerate; and a reduction step for heating and reducing the reduced metal raw material agglomerate to obtain a reduced metal.

  The invention according to claim 8 is a binder having a water content of 10% by mass or more by adding a binder to a fine powder material having a volume average diameter of less than 30 μm containing a metal oxide and a carbonaceous reducing material, and mixing the binder. A binder addition step for forming an added slurry, a raw material drying step for drying the binder-added slurry to a predetermined moisture content to obtain a binder-added dry raw material, and a reduced metal raw material agglomerate by compression molding the binder-added dry raw material A reduced metal production method comprising: a compression molding step, and a reduction step of heating and reducing the reduced metal raw material agglomerate to obtain a reduced metal.

  The present invention is configured as described above. When the binder is added and mixed, since the raw material is in a slurry state, it can be easily mixed without increasing the adhesiveness of the raw material. Moreover, since it mixes with a coarse-grain dry raw material as needed after drying after binder addition, it can mix easily, without the viscosity of a raw material increasing. In addition, since the binder can be added and mixed in the presence of moisture in the raw material, a normal binder can be used, and the adhesive function of the binder is exhibited even after drying. Of briquettes. And since it can shape | mold in a dry state, a briquette can be directly charged into a reduction furnace, without drying. Therefore, according to the present invention, it is possible to use a normal binder, easy mixing of raw materials, without increasing the pressurizing force of the briquette molding machine, and low-cost reduced metal raw material lump that does not require drying of briquettes A method for producing the composition can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a flowchart showing an example of a schematic equipment configuration in a reduced iron manufacturing process according to the embodiment of the present invention. Here, in this example, the same reference numerals as those in FIGS. 2 and 3 are attached to the same equipment as the conventional process shown in FIGS. The difference from the conventional process shown in FIG. 2 is that instead of omitting the raw granulated product drying process (dryer 5), a binder addition process (mixer 1) and a raw material drying process (dryer 2) are newly provided. The difference from the conventional process shown in FIG. 3 is that a binder addition process (mixer 1) and a raw material drying process (dryer 2) are newly provided.

 [Binder addition process]: As shown in FIG. 1, first, for example, electric furnace dust A as a fine powder raw material containing iron oxide (metal oxide), for example, molasses C as a binder and, if necessary, moisture D are added. Then, the mixture is mixed with, for example, a Raedig mixer 1 as a mixer to form a slurry-like binder-added slurry A1. By mixing in the form of a slurry having a high water content, the mixture can be mixed while the tackiness of the mixture is low. In addition, since the binder C can be added and mixed in the presence of moisture, a normal binder C such as molasses can be used without using a special binder such as a paper fluff disclosed in the above-mentioned conventional technique 2.

  As the fine powder raw material A to which the present invention is applied, it is desirable to target a material having a volume average diameter of less than 30 μm, more preferably less than 20 μm, particularly less than 10 μm. This is because, in the fine powder raw material A having such a particle size, the adhesiveness of the mixture is particularly high when the water content is not appropriate.

  The water content of the binder-added slurry A1 is preferably 10% by mass or more in terms of the external number. This is because, although the water content to be slurried varies depending on the type (brand) and particle size of the fine powder raw material A, it is usually difficult to form a slurry at less than 10% by mass. There is no particular upper limit on the water content of the slurry A1, but if the water content is too high, the fuel consumption required for drying in the raw material drying step in the next step will be excessive, so that it is as small as possible within the range of slurrying. Is preferable.

  In the above, “adding moisture D if necessary” means that when the fine powder raw material A originally has a sufficiently high moisture content and is in a slurry state, it is not necessary to add moisture D, and fine powder When the raw material A is dry powder or has a low water content, it means that an appropriate amount of water needs to be added so as to form a slurry.

[Raw material drying process]
Next, the binder-added slurry A1 is dried by, for example, a rotary dryer 2 as a dryer to obtain a binder-added dry raw material A2. Drying is not necessarily performed until moisture has been completely removed. Even if the briquette F after compression molding is inserted into the reduction furnace 6 as it is, it does not cause bursting in the furnace (that is, in the briquette F (that is, It is sufficient to reduce the residual water content in the binder-added dry raw material A2 to such an extent that the water content in the dry mixture E) is 3% by mass or less, preferably 1% by mass or less. In addition, it is desirable to appropriately adjust the drying temperature in the range of 100 to 250 ° C., for example, in accordance with the type of the binder so that the binder does not deteriorate due to heating during drying and the effect as the binder does not disappear. .

[Addition and mixing process]
For example, coke powder B as a coarse powder dry raw material containing a carbonaceous reducing material is added to the binder-added dry raw material A2, and mixed with, for example, a Raedig mixer 3 as a mixer to obtain a dry mixture E. Since it can be mixed in a dry state substantially free of moisture, the problem due to the increase in the stickiness of the mixture as in the prior art 1 does not occur. As the coarse powder dry raw material B, one having a volume average diameter of 30 μm or more, more preferably 50 μm or more, and particularly preferably 100 μm or more is preferably used. By using a particle having such a particle size, the particle size is different from that of the binder-added dry raw material A2, so that the packing density is increased during compression molding of the dry mixture E, and a high-strength briquette F is obtained. However, if the coarse powder dry raw material B is too coarse, the number of joint points with the binder-added dry raw material A2 is reduced, and the strength of the briquette F is reduced, and the surface area of the particles is reduced and the reduction rate is reduced. The volume average diameter of the coarse powder dry raw material B is 500 μm or less, more preferably 300 μm or less, and particularly preferably 200 μm or less. Note that the amount of coke powder B added is sufficient to reduce iron oxide (metal oxide) in the binder-added dry raw material A2. The addition / mixing of the coarse powder dry raw material B to the binder-added dry raw material A2 may be performed after the entire amount of the coarse powder dry raw material B has been added to the binder-added dry raw material A2, or may be mixed all at once. You may mix, adding coarse powder dry raw material B to A2.

[Compression molding process]
Then, this dry mixture E is compression-molded at a relatively low pressure by, for example, a twin-roll briquette molding machine 4 as a compression molding machine, and a reduced iron raw material briquette (hereinafter referred to as a reduced metal raw material agglomerate) having a particle diameter of several tens of millimeters, for example. , Also simply called “briquette”.) Although the detailed mechanism is unknown at this stage, the binder C in the dry mixture E is once mixed with the fine powder raw material A in the presence of water, and is dispersed between the particles of the fine raw material A together with moisture, and then the drying step. It is assumed that even if the moisture is removed through the process, the function as a binder, that is, the particle bonding function is maintained, and a high-strength briquette F can be obtained even by compression molding at a relatively low pressure.

[Reduction process]
The briquette F manufactured in the compression molding step is charged on a moving hearth (not shown) that rotates horizontally in the rotary hearth furnace 5 via a charging device (not shown) of a rotary hearth furnace 6 as a reduction furnace. And in the rotary hearth furnace 5, for example, by heating at an atmospheric temperature of 1100 to 1450 ° C. and a residence time of 8 to 20 minutes, the iron oxide in the fine powder material A (with the carbonaceous reducing material B incorporated in the briquette F) ( Metal oxide) is rapidly reduced, and reduced iron (reduced metal) H with high productivity and high yield and high metallization rate is obtained.

  In the embodiment described above, the electric furnace dust is exemplified as the fine powder raw material A containing metal oxide, and the coke powder is exemplified as the coarse powder dry raw material B containing the carbonaceous reducing material. However, the present invention is not limited thereto.

  That is, as the fine powder raw material A containing metal oxide, in addition to electric furnace dust, iron mill dust containing iron oxide such as blast furnace dust, converter dust, mill scale, mill sludge, or iron ore powder may be used. In addition to iron, those containing metal element oxides such as Ni, Mn, Cr, Mo, Ti may be used. Moreover, you may use combining these 2 or more types.

  As the coarse powder dry material B containing the carbonaceous reducing material, in addition to coke powder, coal, char, charcoal, waste toner, biomass and other carbides, carbon-containing dust such as blast furnace dust, and the like may be used. Moreover, you may use combining these 2 or more types.

  Moreover, in the said embodiment, although the thing containing a metal oxide as a fine powder raw material A and the thing containing a carbonaceous reducing material as a coarse powder dry raw material B were used, it is not limited to this combination, What is the said embodiment? Conversely, a fine powder raw material A containing a carbonaceous reducing material and a coarse powder dry raw material B containing a metal oxide may be used. Furthermore, you may use what contains both a metal oxide and a carbonaceous reducing material in both the fine powder raw material A and the coarse powder dry raw material B or any one (for example, blast furnace dust). Moreover, the coarse powder dry raw material B does not need to be used for the fine powder raw material A using what contains both a metal oxide and a carbonaceous reducing material.

  In the above embodiment, molasses is used as the binder C, a rotary dryer is used as the dryer 2, a twin roll briquette forming machine is used as the compression molding machine 4, a reduced iron raw material briquette (briquette) is used as the reduced metal raw material agglomerate F, and a reduction furnace. Although a rotary hearth furnace is exemplified as 6 and reduced iron is exemplified as the reduced metal H, the invention is not limited thereto.

  As the binder C, flour, lignin, bentonite, quicklime, slaked lime, etc. may be used in addition to molasses.

  As the dryer 2, a low-temperature dryer or the like may be used in addition to a rotary dryer, and sun drying may be used instead of a mechanical dryer.

  As the compression molding machine 4, besides a twin roll briquette molding machine, a tablet molding machine, an extrusion molding machine or the like may be used. Therefore, as the reduced metal raw material agglomerate F, tablets, plate-like agglomerates, rod-like agglomerates and the like may be used in addition to briquettes.

  As the reduction furnace 6, a linear hearth furnace may be used in addition to a rotary hearth furnace.

  The element contained in the reduced metal H to be produced may contain non-ferrous metals such as Mn, Ni, Cr, Mo and Ti in addition to Fe, and the form of the reduced metal H is represented by reduced iron. In addition to sponge metal, molten metal, solid metal solidified after melting, or the like may be used.

  In order to confirm the effect of the present invention, a briquette manufacturing experiment was conducted using a small experimental apparatus.

(Invention Example 1)
As a fine powder raw material containing iron oxide and a carbonaceous reducing material, an electric furnace dust blended with coke powder was used. In this experiment, no coarse powder dry material was used. The volume average diameter of each raw material was measured using a laser diffraction / scattering particle size measuring device (Microtrac FRA, manufactured by Leed & Northrup), and the electric furnace dust was 0.64 μm and the coke powder was 132.7 μm. It was. The electric furnace dust and coke powder in a dry state were blended at a mass ratio of 83:17 to obtain a fine powder raw material (the volume average diameter of the fine powder raw material is the volume average diameter of the electric furnace dust and coke powder. It is about 23 μm when calculated by weighted average with the mass ratio). Then, 5% by mass of molasses and 10% by mass of water are added as binder to the fine powder raw material, and the mixture is placed in a plastic bag and kneaded by hand for 3 minutes. It was. Subsequently, this binder-added slurry was spread on a bat and sufficiently dried in an electric heating type small dryer at 105 ° C. for 24 hours to obtain a dry mixture. This dry mixture was filled into a mold having an inner diameter of 20 mm, and compression-molded by applying a load of 2 t with a die to produce a tablet having a thickness of 8.4 to 8.8 mm [Sample No. 1].

(Comparative Example 1)
With respect to the same fine powder raw material as in Invention Example 1, 5% by mass of molasses and 5% by mass of water were added, and this was put in a plastic bag and mixed by hand for 3 minutes to obtain a water-containing mixture. This water-containing mixture was directly compressed and produced in the same manner and under the same conditions as in the above-mentioned invention without drying, to produce a water-containing tablet. This water-containing tablet was sufficiently dried in the above-mentioned electric heating type small dryer under the conditions of 105 ° C. and 24 hours to obtain a dry tablet [Sample No. 2].

(Invention Example 2)
Instead of the combination of electric furnace dust and coke powder in Invention Example 1 above, a tablet was produced by the same method and conditions as in Invention Example 1 except that a combination of iron ore powder and coal powder was used [Sample No. 3]. The volume average diameter of each raw material was 40 μm for iron ore powder and 35 μm for coal powder.

(Comparative Example 2)
Instead of the combination of electric furnace dust and coke powder of Comparative Example 1 above, a dry tablet was produced in the same manner and conditions as in Comparative Example 1 except that the combination of iron ore powder and coal powder was used [Sample No. . 4].

[Physical property measurement results]
The apparent density, crushing strength, and drop strength of each tablet were measured. The measurement results are shown in Table 1.

  As shown in Table 1, when the mixture of the inventive binder and moisture was molded after drying (Sample Nos. 1 and 3), it was dried after molding as the comparative example (Sample Nos. 1 and 3). ), There is almost no change in the apparent density, the crushing strength shows a little lower value, but 50N / piece required for the rotary hearth furnace is secured, and the drop strength is both 50 times or more. So it can withstand practical use.

  In the above examples, a method of forcibly mixing a small amount of sample by hand mixing was adopted, but this is to avoid the problem caused by the increase in stickiness during mixing of the hydrous raw material of Comparative Example 1. By the way, a sample having the same composition as in Comparative Example 1 (however, the amount of water added was 2-3% by mass, which is slightly less than 5% by mass of Comparative Example 1) in the actual equipment, was readied with a Redich mixer (single screw). Was mixed with a paddle mixer), cut out with a hollow screw feeder, and attempted to be compression molded with a briquette molding machine. However, powder compaction occurred inside these devices, causing trips due to overload and continuous operation. There wasn't.

It is a flowchart which shows the example of the schematic equipment structure in the reduced iron manufacturing process which concerns on Embodiment 1 of this invention. It is a flowchart which shows the schematic installation structure in the reduced iron manufacturing process of the prior art 1. FIG. It is a flowchart which shows the schematic installation structure in the reduced iron manufacturing process of the prior art 1. FIG.

Explanation of symbols

1 ... Mixer (Ledig mixer)
2 ... Dryer (rotary dryer)
3 ... Mixer (Ledig mixer)
4 ... Compression molding machine (briquette molding machine)
6 ... Reduction furnace (rotary hearth furnace)
A ... Fine powder raw material (electric furnace dust)
A1 ... Binder-added slurry A2 ... Binder-added dry raw material B ... Coarse powder dry raw material (coke powder)
C ... Binder (molasses)
D ... moisture E ... dry mixture F ... reduced metal raw material agglomerate (reduced iron raw material briquette)
H ... Reduced metal (reduced iron)

Claims (8)

A binder is added to a fine powder raw material containing metal oxide and / or a carbonaceous reducing material, and this is mixed to form a slurry-like binder-added slurry, and this binder-added slurry is dried to form a binder-added dry raw material. A reduced metal raw material agglomerate obtained by adding and mixing a coarse powder dry raw material containing a metal oxide and / or a carbonaceous reducing material to the additional dry raw material to form a dry mixture, and compression-molding this dry mixture. The reduced metal raw material agglomerate according to claim 1, wherein the fine powder raw material has a volume average diameter of less than 30 µm. The reduced metal raw material agglomerate according to claim 1 or 2, wherein the water content of the binder-added slurry is 10% by mass or more. The reduced metal raw material agglomerate according to any one of claims 1 to 3, wherein the water content is 3% by mass or less. A binder addition step of adding a binder to a fine powder raw material having a volume average diameter of less than 30 μm containing a metal oxide and / or a carbonaceous reducing material, and mixing the resulting mixture to obtain a binder-added slurry having a moisture content of 10% by mass or more. When,
A raw material drying step of drying the binder-added slurry to a predetermined moisture content to form a binder-added dry raw material;
A dry powder having a volume average diameter of 30 μm or more containing a metal oxide and / or carbonaceous reducing material is added to and mixed with the binder-added dry raw material to form a dry mixture having a water content of 3% by mass or less. A compression molding process in which the mixture is compression molded into a reduced metal raw material agglomerate;
A method for producing a reduced metal raw material agglomerate, comprising: A binder addition step of adding a binder to a fine powder raw material having a volume average diameter of less than 30 μm containing a metal oxide and / or a carbonaceous reducing material, and mixing the resulting mixture to obtain a binder-added slurry having a moisture content of 10% by mass or more. When,
A raw material drying step of drying the binder-added slurry to a predetermined moisture content to form a binder-added dry raw material;
A compression molding step in which the binder-added dry raw material is compression-molded to form a reduced metal raw material agglomerate;
A method for producing a reduced metal raw material agglomerate, comprising: A binder addition step of adding a binder to a fine powder raw material having a volume average diameter of less than 30 μm containing a metal oxide and / or a carbonaceous reducing material, and mixing the resulting mixture to obtain a binder-added slurry having a moisture content of 10% by mass or more. When,
A raw material drying step of drying the binder-added slurry to a predetermined moisture content to form a binder-added dry raw material;
Addition and mixing to this binder-added dry raw material, adding and mixing a coarse powder dry raw material containing a metal oxide and / or carbonaceous reducing material with a volume average diameter of 30 μm or more to form a dry mixture having a moisture content of 3% by mass or less Process,
A compression molding step of compressing and molding this dry mixture into a reduced metal raw material agglomerate;
A reduction step of heating and reducing the reduced metal raw material agglomerate to form a reduced metal;
A method for producing a reduced metal, comprising: A binder addition step in which a binder is added to a fine powder raw material having a volume average diameter of less than 30 μm containing a metal oxide and a carbonaceous reducing material, and this is mixed to form a binder-added slurry having a moisture content of 10% by mass or more in an external number;
A raw material drying step of drying the binder-added slurry to a predetermined moisture content to form a binder-added dry raw material;
A compression molding step in which the binder-added dry raw material is compression-molded to form a reduced metal raw material agglomerate;
And a reduction step of heating and reducing the reduced metal raw material agglomerate to obtain a reduced metal.

Images