JP4918754B2 - Semi-reduced sintered ore and method for producing the same - Google Patents

Description

  The present invention relates to a semi-reduced sintered ore that is formed by sintering raw materials such as iron ore, carbonaceous materials, and CaO-based auxiliary materials and used as a blast furnace raw material and the like, and a method for producing the same.

Sinter ore, which is the main raw material of the blast furnace ironmaking method, is generally manufactured as follows. First, a CaO-based auxiliary material (also referred to as a lime-based auxiliary material) containing CaO such as limestone, quicklime, and dolomite in fine iron ore having an average particle size of 2.0 to 3.0 mm, which is about 8 mm or less, meteorite, containing SiO ₂ raw material such as nickel slag, generated in steelworks recovered powder recycled product, 3 to 5 mm smaller than sintered powder requiring particle size is small refiring, and coke powder, a carbonaceous material such as anthracite added, Further, an appropriate amount of water is added to adjust the humidity, and these are mixed and granulated to obtain pseudo particles having an average particle diameter of 3.0 to 5.0 mm. Next, the pseudo particles are filled to a height of about 400 to 600 mm on a pallet of an endless moving type sintering machine, the carbon material on the surface layer of the packed bed is ignited, and the carbon material is drawn while sucking air downward. It burns, and the pseudo-particles which are raw materials are sintered by the combustion heat at that time. The sintered cake obtained by sintering is crushed and sized to obtain a product sintered ore of 3 to 5 mm or more.

  Such sintered ore is charged into a blast furnace and gas-reduced mainly by CO to become pig iron.

Normally, the blast furnace ironmaking method mainly uses indirect reduction with CO gas, so it is restricted by gas reduction equilibrium, requires a large amount of reducing material, and is strong in terms of ensuring air permeability in the blast furnace. High quality high quality coke is required. In contrast, in recent years, from the viewpoint of global warming countermeasures by suppressing CO ₂ emissions and extending the life of coke ovens that are aging, direct iron oxide by carbon (hereinafter referred to as C) as a steelmaking process A process that mainly uses reduction has been developed and put into practical use. In this case, since there is no restriction on the gas reduction equilibrium, the basic unit of the reducing material can be reduced, and CO ₂ emission can be suppressed and the coke oven operating rate can be reduced.

  Examples of the method for producing reduced iron using direct reduction include a smelting reduction method, a rotary hearth method, and a rotary kiln method, all of which involve large-scale capital investment and extremely low productivity. For the reason, it is a supplementary process of the blast furnace method at present.

  On the other hand, a method has been proposed in which an existing sintering machine is used, and a reduction reaction is performed simultaneously with agglomeration on the sintering machine to produce a sintered ore partially including a structure reduced to metallic Fe. .

  For example, in Patent Document 1, 5-20 wt% of powdered coke and anthracite are blended and granulated into powdered ore to form an inner layer, and the outer layer is mixed and coated with powdered ore, auxiliary materials and 2 to 5 wt% of powdered coke and anthracite. After forming two-layer pseudo-grains, mixing and granulating this as part of the sintering raw material, the melt produced from the outer layer of the raw material in the sintering process and direct reduction in the inner layer of powdered coke and anthracite, A method for producing a semi-reduced sintered ore characterized by reducing a part of the sintered ore is disclosed. In this technique, when powder coke and anthracite are confined in the interior, the powder coke and anthracite do not react with oxygen in the air in the first half of the temperature raising process in the sintering process, so they do not react and become FeO + C = only at a high temperature of 1100 ° C. A reduction reaction of Fe + CO-36350 kcal / kmol is caused to produce metallic Fe in a part of the sintered ore. Since this reaction is an endothermic reaction, it is possible to prevent heat from being excessive.

  According to Patent Document 2, CaO is coated on the surface layer of pseudo particles obtained by adding 15 to 18% of a carbonaceous material to iron ore or granulated, or the granulated pseudo particles are added to a solution in which CaO is dissolved. By dipping and adding CaO to the surface of the pseudo particles, re-oxidation after firing is prevented, and a semi-reduced sintered ore with a high reduction rate can be produced.

  In such an existing sintering machine, the method of producing semi-reduced sintered ore by using the direct reduction reaction and adding the carbon material required for reduction to fine iron ore involves a new large-scale capital investment. This is a highly feasible method for producing semi-reduced sintered ore in large quantities without any problems. The semi-reduced sintered ore obtained with the existing sintering machine is used in a large amount in a blast furnace even if the ratio of metallic Fe contained in the sintered ore is low, and is used for reducing ore production. If the carbonaceous material to be contained contains C to some extent, there is almost no restriction on the quality, and dust collection dust etc. can be used, so the total effect such as reducing the blast furnace reducing material ratio and reducing the load on the coke oven is great .

However, in the techniques shown in Patent Documents 1 and 2, it is necessary to burn about 2 to 4 times as much carbonaceous material as that of a normal sinter process, so even if the reduction reaction is an endothermic reaction, It tends to be excessive, and when it is reduced from Fe ₂ O ₃ or Fe ₃ O ₄ to FeO at high temperature, it reacts with gangue in the ore and added flux to generate a large amount of melt. . This melt is composed of a calcium ferrite melt generated by a reaction between a CaO-based auxiliary material added as an auxiliary material and ore, and an olivine-based melt generated by a reaction between FeO formed by reduction and gangue SiO ₂ in the ore. It is a liquid. The melt generated in a large amount in this way rapidly melts the surrounding particles, and at the same time, advances the melting from the outside to the inside of the pseudo particles. A huge void is formed in the sintering bed, which is the raw material packed layer, by melting and shrinking of the pseudo particles, and the suction gas in the sintering machine passes only through that portion. As a result, the sintering reaction in which the combustion zone should move gradually from the upper layer to the lower layer of the raw material packed layer, which is usually 400 to 600 mm, is hindered, and a large amount of unburned portion remains in the lower layer portion of the sintering bed. There is a problem that progress is prevented and productivity is extremely lowered.

For this reason, there is a problem in producing a sintered ore partially reduced in large quantities on a scale of several thousand tons per day as a main raw material of a blast furnace using an existing sintering machine.
JP-A-4-210432 JP 2000-192154 A

The present invention has been made in view of such circumstances, and can be manufactured without deteriorating the operation of the current sintering machine, a part of iron ore is reduced, and semi-reduction sintering containing metal Fe The purpose is to provide ore.
In addition, it is possible to produce a large amount of semi-reduced sintered ore containing a metal Fe partly reduced by advancing direct reduction without deteriorating the operation of the current sintering machine. It aims at providing the manufacturing method of a reduction sintered ore.
Furthermore, it aims at providing the manufacturing method of the semi-reduction sintered ore which can stabilize reaction in a sintering process and can achieve a high reduction rate and a high metal iron content rate.

In order to solve the above problems, in the first aspect of the present invention , a raw material layer is formed by using iron ore, a carbon material, and a CaO-based auxiliary material as a sintering material, and charging the sintering material into a sintering machine. and, the material layer becomes by sintering, a semi-reduced sintered ore portion of the iron ore is reduced, a component excluding the ignition loss of the iron ore or reduced iron producing particles for CaO / SiO ₂ A plurality of powders formed by molding a mixed powder obtained by adding CaO-based auxiliary materials to iron ore so that the mass ratio is 1 or more, and a carbon material of 5 mass % or more in external number with respect to the iron ore or the mixed powder. The reduced iron production particles constitute 5 to 50 mass% of the raw material layer as a part of the sintered raw material, the volume per one of the reduced iron production particles is 10 cm ³ or less, and iron ore is obtained by firing. some of the stone is reduced, and the average value of the entire sintered ore, more than 3 mass% Providing a semi-reduced sinter, characterized in that it contains the genus Fe.

In the second aspect of the present invention , iron ore, a carbon material, and a CaO-based auxiliary material are used as a sintering raw material, and the raw material layer is formed by charging the sintering raw material into a sintering machine. Then, a method for producing the semi-reduced sintered ore of the first aspect, wherein the volume per piece is formed by molding iron ore and a carbon material having an outer number of 5 mass% or more with respect to the iron ore. A part of iron ore is reduced by mixing and firing a plurality of particles for producing reduced iron having a size of 10 cm ³ or less as a part of the sintering raw material so as to be 5 to 50 mass% of the raw material layer. A method for producing a semi-reduced sintered ore, characterized in that the semi-reduced sintered ore containing 3 mass% or more of metal Fe as an average value of the entire sintered ore, is provided.

In the third aspect of the present invention , iron ore, a carbon material, and a CaO-based auxiliary material are used as a sintering raw material, and the raw material layer is formed by charging the sintering raw material into a sintering machine. A method for producing the semi-reduced sintered ore of the first aspect, wherein a mixed powder obtained by adding a CaO-based auxiliary material to iron ore and a carbonaceous material having an external number of 5 mass% or more with respect to the mixed powder. The resultant is formed into a plurality of particles for producing reduced iron having a volume of 10 cm ³ or less, and the CaO-based auxiliary material is a component excluding the loss of ignition of the particles for producing reduced iron, and CaO / SiO _2. The reduced iron production particles are mixed and fired so as to be 5 to 50 mass% of the raw material layer as a part of the sintered raw material. and returning a portion of the stone, as an average value of the entire sintered ore, a 3 mass% or more metals Fe To provide a method of manufacturing a semi-reduced sintered ore, characterized in that the semi-reduced sinter having.

In the second and third aspects , as the reduced iron-producing particles, those obtained by compressing a raw material with a roll molding machine or those obtained by rolling and granulating the raw material can be used.

In the fourth aspect of the present invention , iron ore, a carbon material, and a CaO-based auxiliary material are used as a sintering raw material, and the raw material layer is formed by charging the sintering raw material into a sintering machine. The semi-reduced sintered ore according to the first aspect of the invention, wherein iron ore and iron ore are mixed with 10 to 20% by mass of carbonaceous material, and water and as required The binder is added and mixed, and the mixture is compression-molded with a roll molding machine to obtain a plurality of particles for producing reduced iron having a volume of 10 cm ³ or less, and the particles for producing reduced iron are sintered. as part of the raw materials, combined mixed so that 5～50Mass% of the raw material layer, by reducing part of the iron ore by calcination, as an average value of the entire sintered ore, a 3 mass% or more metals Fe Provided is a method for producing a semi-reduced sintered ore characterized by containing.

In the fourth aspect, it is preferable that the sintering raw material for producing the reduced iron-producing particles is 8 mm or less for iron ore and 5 mm or less for carbonaceous material. In this case, the raw material for producing the particles for producing reduced iron preferably contains 40% by mass or more of particles of 125 μm or less.

In the fifth aspect of the present invention , iron ore, a carbon material, and a CaO-based auxiliary material are used as a sintering raw material, and the raw material layer is formed by charging the sintering raw material into a sintering machine. And a method for producing the semi-reduced sintered ore of the first aspect, wherein a mixed powder obtained by adding a CaO-based auxiliary material to iron ore and a mixed powder with an external number of 10 to 20 mass% carbonaceous material. Mix, further add water and a binder as necessary, and mix this mixture with a roll molding machine to form a plurality of particles for producing reduced iron having a volume of 10 cm ³ or less. The CaO-based auxiliary material is a component excluding the loss of ignition of the reduced iron production particles so that CaO / SiO ₂ is 1 or more, and the reduced iron production particles are used as a part of the sintered raw material. as a combined mixed so that 5～50Mass% of the raw material layer,
Provided is a method for producing a semi-reduced sintered ore, characterized in that a part of iron ore is reduced by firing to contain 3 mass% or more of metal Fe as an average value of the entire sintered ore.

In the fifth aspect, it is preferable that the raw material for producing the particles for producing reduced iron is 8 mm or less of iron ore, 5 mm or less of carbonaceous material, and 5 mm or less of CaO-based auxiliary material. In this case, the raw material for producing the particles for producing reduced iron preferably contains 40% by mass or more of particles of 125 μm or less.

In the fourth and fifth aspects , as the reduced iron production particles compression-molded by the roll molding machine, a plurality of briquettes molded into a predetermined shape by the roll molding machine, or a plate shape or a sheet shape by the roll molding machine or Ru can be used as the ground to a predetermined size after molding into a rod shape.

The fourth, Te fifth aspect odor, when charged pre Symbol compression molded reduced iron produced particles for the sintering machine, have preferably be charged into the raw material layer bottom 3/4 region.

Before SL compression molded iron ore and carbonaceous material as a raw material constituting the reduced iron production for particles preferably those having a particle diameter of 125μm or less as a whole they are to be equal to or greater than 70 mass%.

  In the present invention, the binder means one having a function of binding iron ore particles, and examples thereof include starch, tar, molasses, etc. However, in principle, the binder is not particularly limited as long as it has the above function. . However, although the CaO-based auxiliary material has a function of binding iron ore particles, it is not included in the binder referred to in the present invention for the purpose of the present invention.

According to the first to fifth aspects of the present invention, iron ore and carbonaceous material are formed into reduced iron production particles or molded particles, which are charged as part of the raw material layer. The contact with the material is strong, the contact area is large, and the direct reduction reaction occurs only partially, so there is little risk of generating a large amount of melt. It adheres and the oxidation of metal Fe is suppressed and a high metal Fe content can be obtained. For this reason, it is possible to produce a large amount of semi-reduced sintered ore containing part of the iron ore by reducing the direct reduction without deteriorating the operation of the current sintering machine and reducing a part of the iron ore. . Therefore, by using this semi-reduced sintered ore in a blast furnace, it is possible to reduce the amount of reducing material used in the entire manufacturing process, and in turn reduce CO ₂ emissions from the manufacturing process.

  In particular, as in the fourth and fifth aspects of the present invention, iron ore and carbonaceous material are compression-molded by a roll molding machine and charged as a molded particle into a sintering machine as a part of the sintered raw material. By limiting the conditions, the contact between the iron ore and the carbon material is stronger, the contact area can be increased, and the sintering is more optimized, so that the above effect can be further enhanced.

  Further, according to the sixth to ninth aspects of the present invention, a part of iron ore and a part of carbonaceous material among sintered raw materials, or a part of iron ore, a part of carbonaceous material and a secondary raw material among sintered raw materials. Part of the material is pre-compressed and charged into the sintering machine as a compacted body, which increases the contact area between the iron ore and the carbonaceous material, stabilizes the reaction during the sintering process, and increases the reduction rate In addition, since the compression molded body is densified, it is blocked from the outside air, and the oxidation of metallic iron is suppressed, and a high metallic iron content can be obtained.

Then, as in the seventh aspect of the present invention, when the particle sizes of iron ore and carbonaceous material are as fine as 40 mass% or more with a particle size of 125 μm or less as a whole, a higher reduction rate can be obtained. Furthermore, as in the eighth aspect of the present invention, by using quick lime as a CaO source to be contained in the compression molded body, the CaO source and the binder function are combined, and without using a binder during the production of the compression molded body. Since molding becomes possible, cost reduction can be achieved. Furthermore, as in the ninth aspect of the present invention, the CaO source content of the compression-molded product is adjusted so that CaO / SiO ₂ in the compression-molded product excluding loss on ignition becomes 1 or more. The secondary auxiliary material can effectively exhibit the function as an aggregate for maintaining the strength of the compression molded body or the function of preventing the formation of a hardly reducible FeO-SiO ₂ slag as a molten structure of sintered ore. it can. Furthermore, the effect which combined these effects can be exhibited by combining these suitably.

Hereinafter, the present invention will be described in detail.
(First embodiment)
In this embodiment, basically, iron ore, carbonaceous material, and CaO-based auxiliary material are used as sintering raw materials, and this is charged into a sintering machine to form a raw material layer, which is fired and semi-reduced sintered. Produce ore.

  At this time, as part of the raw material layer, a plurality of particles for producing reduced iron obtained by molding iron ore and a carbonaceous material having an external number of usually 5 mass% or more, preferably 10 to 20 mass% or more. Is charged. By firing the raw material layer in this state with a sintering machine, a part of the iron ore is reduced mainly by direct reduction, and a semi-reduced sintered ore containing metal Fe is obtained.

Such a configuration is based on the following findings of the present inventors.
(1) The point for effectively advancing the direct reduction reaction of iron ore by C is the contact state between the carbon material that is the C source and the iron ore that is the substance to be reduced. And it is important that the contact area is large.
(2) Such molded particles contain a large amount of carbonaceous material for proceeding the reduction reaction and may be excessively melted. However, even if the portion is excessively melted, the molded particles are one of the sintering raw materials. Therefore, there is little risk of generating a large amount of melt, and the productivity of the sintered ore is hardly reduced without substantially affecting the ventilation of the entire sintered bed.
(3) Although the reduced particles may be re-oxidized by oxygen in the suction gas, the particles formed from iron ore and carbonaceous materials are in close contact with each other. Maintain the form, and even if the surface is oxidized, the inside is not easily oxidized, and a good reduced state is maintained.

This will be specifically described below.
As in the blast furnace, the reduction reaction of iron ore is carried out by reaction with carbon in carbonaceous materials such as coke represented by formula (1) (direct reduction) and reaction with CO gas represented by formula (2) ( It proceeds by indirect reduction. The CO ₂ gas generated by the indirect reduction becomes CO gas by a reaction expressed by the equation (3) called a solution loss reaction.
Fe ₂ O ₃ + 3 / 2C = 2Fe + 3 / 2CO ₂ (1)
Fe ₂ O ₃ + 3CO = 2Fe + 3CO ₂ (2)
CO ₂ + C = 2CO (3)

  In these reduction reactions, indirect reduction is dominant when the temperature is 900 to 1100 ° C., and direct reduction is dominant when the temperature is 1200 ° C. or higher. In the present invention, when producing the semi-reduced sintered ore, the raw material layer temperature reaches about 1400 ° C., and the residence time of 1200 ° C. or more is lengthened to directly proceed the reduction.

  In this case, the reduced iron production particles have a strong contact between the iron ore that is the substance to be reduced and the carbonaceous material that is the reducing agent, and the contact area is large. The reaction can proceed effectively. Moreover, since the particles for producing reduced iron are charged as a part of the raw material layer, the above reaction occurs locally, and only the portion of the particles for producing reduced iron is melted excessively, generating a large amount of melt. There is little fear. Furthermore, since the particles for producing reduced iron are in close contact with iron ore and carbonaceous material, and maintain their form after reduction, the internal reoxidation is prevented even by oxygen in the suction gas, which is good. The reduced state is maintained. For this reason, reduction can proceed directly without deteriorating the operation of the current sintering machine, a part of iron ore can be reduced, and a large amount of semi-reduced sintered ore containing metal Fe can be produced. it can.

Reduce the amount of reducing material used (reducing material ratio) as a whole of the ironmaking process by using semi-reduced sintered ore containing metal Fe in part of such iron ore in a blast furnace. As a result, CO ₂ emissions from the ironmaking process can also be reduced. In particular, the effect of reducing CO ₂ emission from the ironmaking process can be increased by preferentially precipitating metal Fe.

This point will be described in more detail.
FIG. 1 is a graph showing the relationship between the sinter ore reduction rate on the horizontal axis and the blast furnace reductant ratio on the vertical axis. The amount of pulverized coal injected is 131 kg / thm (131 kg per ton of hot metal). ). As shown in this figure, it can be seen that when the reduction rate of sintered ore increases, the reducing material ratio of the blast furnace decreases, and when the reduction rate exceeds 30%, the reduction rate becomes abrupt. Since the normal sintered ore has a reduction rate of about 2%, by obtaining a semi-reduced sintered ore having a reduction rate of 30% or more according to this embodiment, the reducing material ratio of the blast furnace can be greatly reduced. .

Although the reducing material ratio of the blast furnace can be lowered by increasing the reduction rate of the sinter in this way, as described above, from the viewpoint of more effectively reducing the CO ₂ emission amount, It is preferable to deposit metal Fe rather than to uniformly increase the reduction rate of the metal. This will be described with reference to FIG. In Fig. 2, the horizontal axis represents the average reduction rate of the sinter during blast furnace charging, and the vertical axis represents the amount of C discharged from the ironmaking process. It is a figure which compares and shows C discharge | emission amount with the sintered ore which generate | occur | produced automatically. The line (a) is a case of a sintered ore that has been partially partially reduced uniformly, and the line (b) is a case of a sintered ore in which metal is preferentially generated. There will be between a) and line (b). In addition, "base" in a figure shows C discharge | emission amount when using the sintered ore which is not partially reduced. As is clear from this figure, it can be understood that the amount of C emission, that is, the amount of CO ₂ emission, can be further reduced by containing a larger amount of metal Fe than when the partial reduction is uniformly performed. In addition, in the case of semi-reduced sintered ore that has been partially partially reduced uniformly, the amount of C emission increases rather than the reduction rate up to 30%, and it seems that there is a similar tendency even if metal Fe is present to some extent. Therefore, it is understood that the reduction rate is preferably 30% or more in order to reduce the CO ₂ emission amount.

The amount of metallic Fe contained in the semi-reduced sintered ore is preferably 3 mass% or more as an overall average value. Thus, reducing reducing agent ratio in blast furnace, reduction and CO ₂ emissions in the entire ironmaking process, it is possible to effectively exhibit the effect of load reduction to coke oven.

  When obtaining the semi-reduced sintered ore of the present embodiment, the amount of carbonaceous material in the reduced iron production particles is preferably 5 mass% or more. This is because if it is less than 5 mass, the direct reduction reaction may not occur effectively. If the carbonaceous material content is 10 mass% or more, it is more preferable for the promotion of the direct reduction reaction. However, if the carbonaceous material exceeds 20 mass%, excessive melting tends to occur, so the carbonaceous material content is 10 to 20 mass%. Is preferred. As the carbon material, powder coke is suitable, but other carbon materials such as anthracite coal or dust collecting powder of coke cooling equipment can be used.

The CaO-based auxiliary material may be blended in the reduced iron production particles after firing so that the mass ratio of CaO / SiO ₂ is 1 or more with the components excluding the loss on ignition. The CaO-based auxiliary material has a function as an aggregate for maintaining the strength of the particles for producing reduced iron, or a function of preventing the formation of hardly-reducible FeO—SiO ₂ -based slag as a molten structure of sintered ore. When the mass ratio of CaO / SiO ₂ system is less than 1, a low melting point and hardly reducible FeO—SiO _{2 system} melt is likely to be generated. On the other hand, even if CaO becomes excessive, it is easy to generate a CaO—Fe ₂ O ₃ -based low melting point melt, and when a large amount of melt is generated, the particles themselves are excessively so as not to leave their shape. There is a possibility of melting. Ordinary iron ore contains about 0.6 to 5.5 mass% of SiO ₂ , and in the current sintering operation, multiple brands (usually 5 to 10 brands) are blended. SiO ₂ is the 3.7~4.8mass%. In order to function as an aggregate, the content of the CaO-based auxiliary material is preferably 2 mass% or more in terms of CaO. Further, in order to prevent the formation of a hardly sinterable SiO ₂ —CaO-based melt and to prevent a large amount of CaO—Fe ₂ O ₃ -based low melting point melt, the content of the CaO auxiliary material is CaO. It is preferable to set it as 8 mass% or less in conversion. The CaO-based auxiliary material (also referred to as a lime-based auxiliary material) is not particularly limited as long as it contains a CaO content, but typical examples include limestone, quicklime, and dolomite.

  Of the raw materials constituting the particles for producing reduced iron, the iron ore preferably has a particle size of 8 mm or less, the carbon material has a particle size of 5 mm or less, and the CaO-based auxiliary material has a particle size of 5 mm or less. Thus, by reducing the particle size of the raw material, it is possible to increase the contact area between the iron ore and the carbonaceous material and effectively cause a reduction reaction, thereby obtaining reduced particles with high density.

  Moreover, it is preferable that the particle | grains for iron ore and carbon | charcoal materials in it are 40 mass% or more of the particles for reduced iron manufacture at least the particle | grains of 125 micrometers or less. Thus, by atomizing the iron ore and the carbonaceous material, the reactivity of the reduction reaction between them increases, and the reduction rate of the iron ore can be further increased. More preferably, it is 70 mass% or more. When the CaO-based auxiliary material is contained in the reduced iron production particles, it is preferable that the particle size of 125 μm or less including the CaO-based auxiliary material is 40 mass% or more, and 70 mass% or more. More preferred.

The size of the particles for producing reduced iron is preferably 10 cm ³ or less. This is because the reduction reaction is an endothermic reaction, so the heat of combustion is compensated by the amount of combustion heat of coke at the time of sinter production. It is because it is easy to become. By setting it to 10 cm ³ or less, the reduction reaction proceeds sufficiently, and the effect of improving the air permeability of the raw material layer is exhibited. However, when the size of the particles for producing reduced iron is smaller than 0.065 cm ³ (corresponding to a sphere having a diameter of 5 mm), it becomes smaller than the surrounding granulated product and assimilates and melts with the granulated product during firing. If it is too small, the air permeability improving effect is hardly exhibited effectively, so 0.065 to 10 cm ³ is preferable. When the air permeability improving effect is more important, 0.3 cm ³ or more is preferable.

The particles for producing reduced iron are preferably 5 to 50 mass%, more preferably 10 to 50 mass% of the entire raw material layer. The particles for producing reduced iron after molding have a relatively high strength, are less likely to collapse when charged into the sintering machine, and function as coarse particles in the raw material layer to ensure ventilation. And it has the function to improve the productivity of sintered ore by blending an appropriate amount. However, if the blending amount exceeds 50 mass% of the entire raw material layer, a layer in which the particles for producing reduced iron are concentrated is formed, and aeration is excessive, so that an unfired part is likely to occur. On the other hand, if the amount of particles for producing reduced iron is less than 5 mass%, the amount of metallic Fe in the obtained semi-reduced sintered ore is reduced, so the effect of reducing the reducing material ratio and reducing CO ₂ emissions in the blast furnace. Tends to be insufficient.

  The particles for producing reduced iron are produced by forming iron ore and a carbonaceous material, or iron ore, a carbonaceous material, and a CaO-based auxiliary material by an appropriate method. The production method in this case is typified by rolling granulation using a drum mixer or a disk pelletizer, which is conventionally known as a method for producing pseudo particles as a sintering raw material, and a briquetting method using a briquette machine. A method of compression molding (also referred to as pressure molding) with a roll molding machine or the like can be given. Of these, the compression molding method is preferred.

  The method of compression molding iron ore and carbonaceous materials, or iron ore, carbonaceous materials and CaO-based auxiliary materials makes the contact between iron ore and carbonaceous materials stronger than the method of forming pseudo particles by rolling granulation. Since these contact areas can be increased, the reduction reaction of iron ore can proceed more easily, and the reduction rate and the content of metallic iron can be further increased.

  This will be described with reference to FIG. In Fig. 3, the horizontal axis represents the reduction rate of sintered ore, and the vertical axis represents the content of metallic iron after sintering, and these relations are shown for the case of pseudo particles by rolling granulation and the case of briquette particles. FIG. As is apparent from this figure, it can be seen that briquette particles have a higher reduction rate when sintered than pseudo particles, and that the content of metal Fe after sintering is higher.

  Further, by using compression-molded particles such as briquette particles, the porosity in the raw material packed layer is increased, and the air permeability of the sintered bed is improved.

  When producing particles for producing reduced iron by compression molding typified by briquetting, it is preferable to carry out compression molding after adding an appropriate amount of water and / or binder to the raw material and mixing them. Also in this case of forming by rolling granulation, it is preferable to perform rolling granulation after adding an appropriate amount of water and / or binder to the raw material and mixing them.

  As the remainder of the raw material layer, pseudo particles used for ordinary sintered ore are used. That is, a material formed by rolling and granulating a sintered raw material mainly composed of iron ore, a carbonaceous material, and a CaO-based auxiliary material with a drum mixer, a disk pelletizer, or the like is used. In this case, ordinary iron ore is used as the iron ore, powder coke is used as the carbon material, and limestone or quick lime is used as the CaO-based auxiliary material. The blending ratio is preferably 2 to 6 mass% in terms of the number of carbonaceous materials when the iron ore and CaO-based auxiliary materials are 100 mass%. The CaO-based auxiliary material is preferably about 4 to 10 mass% in the total amount of the iron ore and the CaO-based auxiliary material.

  As a sintering machine, a bottom suction type endless moving type sintering machine is generally used. This downward suction type endless moving type sintering machine has an endless moving type moving grate, on which the reduced iron production particles and normal pseudo particles are supplied to form a raw material layer. This raw material layer is continuously sintered to produce the semi-reduced sintered ore of this embodiment.

Next, a specific example of the method for producing the semi-reduced sintered ore according to the present embodiment will be described.
FIG. 4 is a schematic diagram showing an example of equipment for producing the semi-reduced sintered ore according to the present embodiment. This facility includes a raw material manufacturing facility 40 and a downward suction type endless moving type sintering machine 50.

  The raw material production facility 40 has a normal pseudoparticle raw material source 1 to which iron ore, a carbonaceous material, and a CaO-based auxiliary raw material, which are normal pseudoparticle raw materials, can be supplied, and the raw material from the normal pseudoparticle raw material source 1 Is granulated by a rolling granulator 2 composed of a drum mixer, a disk pelletizer or the like, and usually becomes pseudo particles. The raw material production facility 40 has a raw material source 3 for particles for producing reduced iron that can be supplied with iron ore and carbonaceous materials, or iron ore, carbonaceous materials, and CaO-based auxiliary materials that are raw materials for particles for producing reduced iron. Then, the raw material from the raw material source 3 for particles for producing reduced iron is formed by the forming device 4 such as the above-described roll forming machine or rolling granulator to become particles for producing reduced iron. These normal pseudo particles and particles for producing reduced iron are mixed by a mixer 5 at a predetermined ratio and stored in the hopper 6, for example.

  The downward suction type endless moving type sintering machine 50 has an endless moving type moving grate 11, and on the moving grate 11, normal pseudo particles and particles for producing reduced iron by a roll feeder 10 which is a charging system. And the raw material layer 13 is formed. Alternatively, the normal pseudo particles and the reduced iron production particles may be separately supplied onto the moving grate 11 without using the mixer 5.

  An ignition furnace 12 is provided in the movement path of the moving great 11, and the pseudo particles on the moving great 11 are ignited when passing through the ignition furnace 12, and the sintering of the raw material layer 13 is started. 13a is formed. A crusher (not shown) is provided on the exit side of the moving grate 11, and the sintered ore dropped from the moving grate 11 is pulverized by this crusher, supplied to the conveyor 14, and supplied to the blast furnace.

  A plurality of wind boxes 15 are arranged immediately below the moving grate 11 along the traveling direction of the moving grate 11, and a vertical duct 16 is connected to each wind box 15. Thereby, the gas above the raw material layer 13 is sucked through the raw material layer 13 by the wind box 15 and the vertical duct 16.

  The vertical duct 16 is connected to a main exhaust gas duct 17 arranged horizontally, and exhaust gas is discharged through the main exhaust gas duct 17. An electric dust collector 20 and a main blower 21 are connected to the main exhaust gas duct 17, and the gas above the raw material layer 13 is sucked by the main blower 21, and the wind box 15, the vertical duct 16, the main exhaust gas duct 17, and the electric dust collector. It is discharged from the chimney 22 through 20 etc.

  A gas supply hood may be provided on the downstream side of the ignition furnace 12 above the raw material layer 13 and an exhaust gas circulation duct connected to the hood from the vertical duct 16 may be provided to perform exhaust gas circulation. By adopting such an exhaust gas circulation system, it becomes easy to appropriately control the atmosphere (oxygen concentration) in the raw material layer 13, and it is more effective for the generation of metallic Fe and prevention of reoxidation.

  In the facility configured as above, the raw material from the raw material source 1 for normal pseudo particles is granulated by the rolling granulator 2 to produce the normal pseudo particles, and from the raw material source 3 for particles for producing reduced iron. These raw materials are molded by a molding device 4 to produce particles for producing reduced iron, these ordinary pseudo particles and particles for producing reduced iron are mixed by a mixer 5, and this mixture is passed through a hopper 6 and a roll feeder 10. The raw material layer 13 is formed by feeding onto the moving grate 11 of the downward suction type endless moving type sintering machine 50. At this time, as shown in FIG. 5, the raw material layer 13 is in a state in which the reduced iron production particles 32 are dispersed in the matrix 31 of normal pseudo particles.

  Then, the surface of the raw material layer 13 is ignited by the ignition furnace 12 and fired while sucking the gas downward through the wind box 15 to sinter the pseudo particles constituting the raw material layer 13 to obtain a sintered ore. The sintered ore obtained by sintering in this manner falls from the moving great 11, and the sintered ore dropped by the crusher on the outlet side is crushed and supplied to the conveyor 14, and further supplied to the blast furnace. . In this case, as described above, in the reduced iron production particles 32 of the raw material layer 13, direct reduction occurs between the iron ore and the carbonaceous material, and the iron ore is partially reduced to partially become metal Fe. Semi-reduced sintered ore is produced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.
In this embodiment, at least iron ore, carbonaceous material, and CaO-based auxiliary raw materials are used as sintering raw materials, and this is charged into a sintering machine to form a raw material layer and fired to produce a semi-reduced sintered ore. In doing so, a more specific range of the first embodiment will be defined.

  In this embodiment, 10-20 mass% of carbonaceous material is added to the powdered iron ore and the powdered iron ore, mixed with water and a binder as necessary, and this mixture is roll-formed. The molded particles are compression-molded by a machine, and the molded particles are blended in an amount of 5 to 30 mass% and used as a sintering material to be charged into a sintering machine. And the sintering raw material with which this shaping | molding particle was mix | blended 5-50 mass%, Preferably 5-30 mass% is baked, a part of iron ore is reduce | restored, and 3 mass% or more is obtained as an average value of the whole sintered ore. A semi-reduced sintered ore containing metal Fe is obtained.

  In the present embodiment, as in the first embodiment, when the sintered ore is produced, the raw material layer temperature reaches about 1400 ° C., and the residence time of 1200 ° C. or more is lengthened to directly control the reduction. To do.

  In the present embodiment, molded particles that are compression-molded by a roll molding machine are used as the particles corresponding to the reduced iron production particles of the first embodiment. Such compression-molded molded particles have a higher density than the granulated pseudo particles that are normal sintering raw materials, and as described in the first embodiment, when sintered than the pseudo particles. The reduction ratio is high, and the content of metallic Fe after sintering is high.

In other words, the compacted particles that have been compression-molded by a roll molding machine are in direct reduction because the iron ore that is the substance to be reduced and the carbonaceous material that is the reducing agent are in strong contact with each other and the contact area is large. It is rapidly reduced to metallic Fe. On the other hand, since the inside has a high density, the oxygen diffusion rate is slow, C does not burn, and the reduction reaction proceeds directly when the temperature is raised by heat transfer. As shown in FIG. 6, the surface of the molded particles 63 dispersed in the normal pseudo particles 62 in the sintered packed layer (raw material layer) 61 has an FeO—SiO ₂ or FeO—CaO melt. Thus, a film 64 having a molten structure is formed, and this film 64 prevents a burst due to CO gas or CO ₂ gas generated by direct reduction inside. Therefore, after reduction (after firing), the film 64 remains and retains its shape, and this time, it effectively works to prevent reoxidation of the reduced Fe or FeO. Thus, the shaped particles can effectively advance the direct reduction reaction of iron ore. In addition, since the molded particles are a part of the sintered raw material and are dispersed in the raw material layer in the sintering machine, the above reaction occurs locally, and it is the portion of the particles for producing reduced iron that melts excessively. There is little risk of generating a large amount of melt. Further, the molded particles maintain their form even after reduction as described above, and internal re-oxidation is prevented by oxygen in the suction gas, so that a good reduction state is maintained. The reduction can proceed directly without deteriorating the operation of the steel, and a large amount of semi-reduced sintered ore containing 3% or more of metallic Fe can be produced. As a result, as in the first embodiment, the amount of reducing material used (reducing material ratio) as a whole manufacturing process can be reduced, and the amount of CO ₂ emitted from the manufacturing process can also be reduced. In particular, the effect of reducing CO ₂ emission from the manufacturing process can be increased by preferentially depositing metallic Fe.

  The molded particles effectively reduce iron ore as described above, and since they have high strength, there is little disintegration at the time of charging into the sintering machine, and aeration is ensured in the raw material layer. Therefore, it has a function of improving the productivity of sintered ore by blending an appropriate amount. However, if the blending amount exceeds 30 mass% of the entire sintered raw material, a layer in which the particles for producing reduced iron are concentrated is formed, and aeration is excessive. On the other hand, it becomes difficult to make the metal Fe in the obtained sintered ore 3 mass or more if the particles for producing reduced iron are less than 5 mass%. For this reason, in this embodiment, the compounding quantity in the sintering raw material of a shaping | molding particle shall be 5-30 mass%.

  The reason why the amount of metallic Fe contained in the sintered ore is set to 3 mass% or more as an overall average value is that it can effectively exert the effect of reducing the reducing material ratio in the blast furnace and reducing the load on the coke oven. Because.

In the present embodiment, the amount of the carbonaceous material in the molded particles is set to 10 to 20 mass% or more for the following reason. The total Fe in the iron ore is 56 to 65 mass%, and the Fe is 560 to 650 kg per ton of iron ore. Since Fe in it is considered to be almost Fe ³⁺ , the amount of C necessary for 100% reduction of Fe ₂ O ₃ by the direct reduction reaction of the above formula (1) is 180 to 210 kg, which is a typical carbonaceous material. If the fixed C in a certain powder coke is 88 mass%, the amount of powder coke required to reduce Fe ₂ O ₃ by 100% is 205 to 239 kg / t-iron ore. Since the reduction rate required for actual shaped particles is about 50% or more, the amount of powder coke required is about 100 kg / t-iron ore or more, that is, 10 mass% or more. The metal Fe content of the molded particles is preferably 30 mass%, and the reduction rate at that time is about 60%. Therefore, the necessary carbonaceous material (powder coke) becomes 123 to 143 kg / t-iron ore, which is a theoretical amount of 1. If 2 to 1.3 times is required, the preferable range of the carbonaceous material is about 15 to 19 mass%. Further, if the carbon material exceeds 20 mass%, excessive melting tends to occur, so the upper limit is set to 20 mass%. As the carbon material, powder coke is suitable, but other carbon materials such as anthracite coal or dust collecting powder of coke cooling equipment can be used.

Usually, iron ore contains about ₁ to 5 mass% of SiO ₂ as a gangue and about ₁ to 2.5 mass% of Al ₂ O ₃ . On the other hand, the CaO-based auxiliary material contains almost no gangue. Also, ash major component of coke breeze as a carbonaceous material is SiO ₂ and _Al 2 _{O 3.} Accordingly, when a sintered ore is produced by sintering only with iron ore and carbonaceous material, the slag component is FeO-SiO ₂ slag composed of FeO and SiO ₂ formed by reducing Fe ₂ O ₃ , so-called firelight. Will be generated. Although this firelight has extremely low reducibility, by adding a CaO-based auxiliary material, calcium-ferrite slag can be formed and the reducibility can be improved. Moreover, it also has a function as an aggregate or a binder for maintaining the strength of the CaO-based auxiliary material molded particles. Accordingly, it is preferable that the molded particles contain a CaO-based auxiliary material so that CaO / SiO ₂ is 1 or more, preferably CaO / SiO ₂ > 1.5, with the components excluding the loss on ignition of the molded particles. On the other hand, the CaO-based auxiliary material easily generates a low melting point melt, and when the melt is generated in a large amount, there is a possibility that the particles themselves melt excessively so as not to leave their shape. Therefore, in order to prevent excessive melting of the particles, the content of the CaO-based auxiliary material is preferably 8 mass% or less in terms of CaO. The CaO-based auxiliary material is not particularly limited as long as it contains a CaO component, but typical examples include limestone, quicklime, and dolomite.

  The raw materials constituting the formed particles are preferably iron ore of 8 mm or less, carbonaceous material of 5 mm or less, and CaO-based auxiliary material of 5 mm or less. Thus, by reducing the particle size of the raw material, it is possible to increase the contact area between the iron ore and the carbonaceous material and effectively cause a reduction reaction, thereby obtaining reduced particles with high density.

  Moreover, it is preferable that a shaping | molding particle | grain makes it 40 mass% or more of the particle | grains below 125 micrometers or less as a whole at least the iron ore and carbon material in it. Thus, by atomizing the iron ore and the carbonaceous material, the reactivity of the reduction reaction between them increases, and the reduction rate of the iron ore can be further increased. Here, the iron ore and the carbonaceous material having a particle size of 125 μm or less as a whole is 40 mass% or more. The iron ore and the carbonaceous material are not individually composed of iron ore and the carbonaceous material. It means that the sum of the diameters is 40 mass% or more. More preferably, it is 70 mass% or more. Moreover, it is preferable that the particle | grains of 125 micrometers or less shall be 40 mass% or more about the whole shaping | molding particle | grains including not only an iron ore and a carbonaceous material but CaO type | system | group auxiliary material, and 70 mass% or more is more preferable.

The size of the shaped particles is preferably 10 cm ³ or less. This is because the reduction reaction is an endothermic reaction, so the heat of combustion is compensated by the amount of combustion heat of coke at the time of sinter production. It is because it is easy to become. In the case of 10 cm ³ , the diameter is 26.8 mm, which is a limit from the viewpoint of heat transfer. By setting it to 10 cm ³ or less, the reduction reaction proceeds sufficiently and the air permeability of the raw material layer is improved. . However, when the size of the particles for producing reduced iron is less than 0.065 cm ³ (corresponding to a sphere having a diameter of 5 mm), it is difficult to effectively exhibit the air permeability improvement effect, so 0.065 to 10 cm ³ is preferable. When the air permeability improving effect is more important, 0.3 cm ³ or more is preferable. Further, from the viewpoint of heat conductivity, 6 cm ³ or less is preferable.

  The formed particles are obtained by compression-molding iron ore and a carbonaceous material, or iron ore, a carbonaceous material, and a CaO-based auxiliary material with a roll molding machine or the like. Forming with a roll forming machine is classified into briquetting and compacting. The former is provided so that two rolls, each of which has a plurality of pockets to be a mother mold of a molded product, bite into each other and rotate at the same speed, and a raw material is supplied between these rolls to continuously form a predetermined shape. In the latter case, two rolls in which no pockets are formed are similarly rotated at the same speed to obtain a plate-like molded product, which is then pulverized to obtain molded particles and To do. In this case, compression molding is performed after adding an appropriate amount of water and, if necessary, an appropriate amount of binder to the raw material.

  The molding pressure of the molded particles is preferably 980 kN / m or more. Thereby, a shaping | molding particle can be made into sufficient intensity | strength. An experiment confirming this will be described. Here, 20% by mass of powdered coke (−5 mm) is added to iron ore of 8 mm or less, water is further added to 3%, and a gelatinized starch aqueous solution having a concentration of 40 mass% is used as the binder. An almond briquette having a length of 35 mm, a width of 25 mm, and a thickness of 16 mm was prepared by adding 4 mass% and changing the molding pressure between 245 and 1470 kN / m. Using 20 kg of briquettes at each molding pressure, a drop test was repeated 25 times from a height of 2 m, and a yield of +5 mm was investigated. The result is shown in FIG. As shown in this figure, it was confirmed that good results were obtained at 980 kN / m or more. The yield is saturated at 980 kN / m or more. Note that 2 m × 25 times = 50 m corresponds to the drop distance of the connecting portion of the transport line.

  As the remainder of the raw material layer, pseudo particles used for ordinary sintered ore are used, as in the first embodiment. That is, a material formed by rolling and granulating a sintered raw material mainly composed of iron ore, a carbonaceous material, and a CaO-based auxiliary material with a drum mixer, a disk pelletizer, or the like is used. In this case, ordinary iron ore is used as the iron ore, powder coke is used as the carbon material, and limestone or quick lime is used as the CaO-based auxiliary material. The blending ratio is preferably 4 to 6 mass% in terms of the number of carbonaceous materials when the iron ore and CaO-based auxiliary materials are 100 mass%. The CaO-based auxiliary material is preferably about 4 to 10 mass% in the total amount of the iron ore and the CaO-based auxiliary material.

  As a sintering machine, a lower suction type endless moving type sintering machine is generally used as in the first embodiment. This downward suction type endless moving type sintering machine has an endless moving type moving grate, on which the reduced iron production particles and normal pseudo particles are supplied to form a raw material layer. This raw material layer is continuously sintered to produce the semi-reduced sintered ore of this embodiment.

Next, a specific example of the method for producing the semi-reduced sintered ore according to the present embodiment will be described.
FIG. 8 is a schematic diagram showing an example of equipment for producing the semi-reduced sintered ore according to the present embodiment. This facility includes a molded particle manufacturing facility 100, a pseudo particle manufacturing facility 200, and a downward suction type endless moving type sintering machine 300.

  The molded particle production facility 100 is formed from a raw material hopper group 101 capable of supplying iron ore, carbonaceous materials and CaO-based auxiliary raw materials, a stirrer 102 for mixing raw materials and a binder (for example, starch, tar, molasses), and a mixture. A roll forming machine 103 for obtaining particles, the raw material from the raw material hopper group 101 is conveyed to the stirrer 102 by the conveyors 104 and 105, and the mixture stirred by the stirrer 102 is transferred to the roll forming machine 103 by the conveyor 106. The formed particles produced by the roll forming machine 103 are conveyed to the conveyor 401 that goes to the sintering machine 300 by the conveyor 107.

  The pseudo-particle manufacturing facility 200 includes a raw material hopper group 201 capable of supplying iron ore, carbonaceous material, CaO-based auxiliary raw materials, and the like, and a mixing / humidifying device for mixing these and adding water to adjust the humidity ( Drum) 202 and a granulator (drum) 203 for granulating the raw material, and the raw material from the raw material hopper group 201 is conveyed to the mixer / humidifier (drum) 202 by conveyors 204 and 205. The mixture discharged from the mixer / humidifier (drum) 202 is conveyed to the granulator (drum) 203 by the conveyor 206, and the pseudo particles produced by the granulator (drum) 203 are sintered by the conveyor 207. It is conveyed to a conveyor 401 that goes to the machine 300.

  As a result, the molded particles and the pseudo particles are mixed on the conveyor 401. The mixture on the conveyor 401 is transferred to the conveyor 402 and conveyed to the sintering machine 300.

  The downward suction type endless moving type sintering machine 300 has an endless moving type moving grate 311, and a mixture of normal pseudo particles and molded particles is supplied onto the moving grate 311 by an appropriate charging system. The raw material layer 313 is formed.

  An ignition furnace 312 is provided in the movement path of the moving great 311, and the pseudo particles on the moving great 311 are ignited when passing through the ignition furnace 312 to start sintering of the raw material layer 313. 313a is formed. A crusher (not shown) is provided on the exit side of the moving grate 311, and the sintered ore dropped from the moving grate 311 is pulverized by this crusher, supplied to the conveyor 314, and supplied to the blast furnace.

  A plurality of wind boxes 315 are arranged immediately below the moving grate 311 along the traveling direction of the moving grate 311, and a vertical duct 316 is connected to each wind box 315. Thereby, the gas above the material layer 313 is sucked through the material layer 313 by the wind box 315 and the vertical duct 316.

  The vertical duct 316 is connected to a main exhaust gas duct 317 arranged horizontally, and exhaust gas is discharged through the main exhaust gas duct 317. An electric dust collector 320 and a main blower 321 are connected to the main exhaust gas duct 317, and a gas above the material layer 313 is sucked by the main blower 321, and a wind box 315, a vertical duct 316, a main exhaust gas duct 317, an electric dust collector It is discharged from the chimney 322 through 320 or the like.

  In addition, a gas supply hood may be provided in the downstream portion of the ignition furnace 312 above the raw material layer 313, and an exhaust gas circulation duct connected to the hood from the vertical duct 316 may be provided to perform exhaust gas circulation. By adopting such an exhaust gas circulation system, it becomes easy to appropriately control the atmosphere (oxygen concentration) in the raw material layer 313, which is more effective for the generation of metallic Fe and the prevention of reoxidation.

  In the facility configured as described above, the molded particle is manufactured by the molded particle manufacturing facility 100, the pseudo particle is manufactured by the pseudo particle manufacturing facility 200, and this is mixed on the conveyor 401 by an appropriate means. Then, this mixture is supplied onto the moving grate 311 of the downward suction type endless moving type sintering machine 300 to form the raw material layer 313. At this time, as shown in FIG. 9, the raw material layer 313 is in a state where the shaped particles 332 are dispersed in the matrix 331 of normal pseudo particles.

  Then, the surface of the raw material layer 313 is ignited by the ignition furnace 312 and fired while sucking the gas downward through the wind box 315 to sinter the pseudo particles constituting the raw material layer 313 to obtain a sintered ore. The sintered ore obtained by sintering in this manner falls from the moving great 311, and the sintered ore dropped by the crusher on the outlet side is crushed and supplied to the conveyor 314, and further supplied to the blast furnace. . In this case, as described above, in the shaped particles 332 of the raw material layer 313, direct reduction occurs between the iron ore and the carbonaceous material, and the iron ore is partially reduced and partially reduced into Fe metal. Sinter is produced.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
In the present embodiment, as in the first and second embodiments, in the production of sintered ore, the raw material layer temperature reaches about 1400 ° C., and the residence time of 1200 ° C. or more is lengthened to control direct reduction. However, for this purpose, iron ore, carbonaceous material, and auxiliary raw materials are charged into the sintering machine as a sintering raw material and fired, and part of the iron ore is reduced by the carbonaceous material. When producing ore, part of iron ore and part of carbonaceous materials among sintered raw materials, or part of iron ore, part of carbonaceous materials and part of auxiliary materials among sintered raw materials are compression-molded in advance. A compression-molded body is formed (also referred to as pressure molding), and the remainder of the sintered raw material is granulated, and these are mixed and fired.

Thus, by compression molding part of iron ore and part of carbonaceous material among sintered raw materials, or part of iron ore, part of carbonaceous material and part of auxiliary raw materials among sintered raw materials Since the iron ore and carbonaceous material are consolidated and their contact area is increased, the reduction of the sintered ore is promoted by inserting such a compression molded body into the sintering machine as a part of the raw material. Can do. For this reason, the reduction rate of sintered ore and the content rate of metallic Fe can be increased. By using such a sintered ore in a blast furnace, the reducing material as the whole manufacturing process is obtained as in the first embodiment. The amount used (reducing material ratio) can be reduced, and as a result, the amount of CO ₂ emitted from the manufacturing process can also be reduced.

  In addition, since the raw material of the compression molded body is densified by pressurization, the raw material is present more densely than the granulated product even when it becomes a sintered ore. At this time, the portion densified by compression molding is blocked from the outside air, and the oxidation of metallic iron generated by direct reduction is suppressed.

  That is, a compression-molded body obtained by compression-molding a part of iron ore and a part of carbon material among sintered raw materials, or a part of iron ore, a part of carbon material and a part of auxiliary materials among sintered raw materials. A high reduction rate and a high content of metallic iron are realized by supplying a sintered raw material together with the granulated material of the sintering raw material to produce a semi-reduced sintered ore.

  In this embodiment, from the viewpoint of maintaining good reactivity, the iron ore is preferably a fine iron ore having a particle size of 8 mm or less, and the carbon material is a fine coke having a particle size of 5 mm or less, and further, a particle size of 3 mm or less. Is preferred. As the auxiliary material, CaO-based auxiliary materials such as limestone and quicklime are used.

The composition of the core part of the granulated product (the part excluding the agglomerated material described later) and the composition of the compression-molded product are composed of 10 to 20% by mass of carbonaceous material as a reducing material with respect to 100% by mass of iron ore and auxiliary materials. Is preferred. The content of the auxiliary material is preferably blended so that the basicity (CaO / SiO ₂ ) of the core portion is 1 or more. Specifically, it is preferably 4 to 10% by mass. The core part of the granulated material may be a single layer or, for example, may have a two-layer structure in which an outer layer made of iron ore is formed on the outer side of an inner layer made of iron ore, auxiliary material and carbonaceous material. Good. The granulated material is constituted by coating the carbon material as a fuel (condensation material) on the outside of the core portion. Moreover, you may use the thing by which the carbon material was coat | covered outside as a compression molding body. The carbon material to be coated is preferably 1 to 4% by mass with respect to 100% by mass in total of iron ore and auxiliary materials.

  Here, if the amount of the carbon material in the core portion is 10 to 20% by mass with respect to 100% by mass of the iron ore and the auxiliary raw material, the iron ore in the pseudo particles can be effectively reduced within this range. Moreover, it is because unreacted coke hardly remains. Moreover, sintering of iron ore can be appropriately advanced by setting the amount of carbonaceous material to be sheathed on the core portion to 1 to 4% by mass with respect to 100% by mass of iron ore and auxiliary raw materials in total.

  In this embodiment, the compression molded body is a briquette formed into a predetermined shape by a compression molding means in a roll molding machine, or is crushed to a predetermined size after being formed into a plate shape, a sheet shape, or a rod shape by a roll molding machine. The crushing strength of a single particle is 39.2 N or more.

The compression molded body preferably has a volume of 10 cm ³ or less. By setting it within this range, optimum air permeability can be obtained. If the size is larger than this, the air permeability tends to be excessive, and unfired portions are likely to be generated. However, when the size of the compression molded body particles is smaller than 0.065 cm ^3, it becomes smaller than the surrounding granulated product, and assimilates and melts with the granulated product during firing, and the reduction rate does not sufficiently increase. Therefore, the volume of the compression molded body is more preferably 0.065 to 10 cm ³ . Furthermore, favorable air permeability is obtained by setting the width of the thinnest portion of the compression molded body to 8 mm or more and 20 mm or less.

  It is preferable that the iron ore and carbon material as raw materials constituting the compression-molded body have a particle size of 125 μm or less as a whole and be 40 mass% or more. Thus, by atomizing the iron ore and the carbonaceous material, the reactivity of the reduction reaction between them increases, and the reduction rate of the iron ore can be further increased. Here, the iron ore and the carbonaceous material having a particle size of 125 μm or less as a whole is 40 mass% or more. The iron ore and the carbonaceous material are not individually composed of iron ore and the carbonaceous material. It means that the sum of the diameters is 40 mass% or more. More preferably, it is 70 mass% or more. Moreover, it is preferable that the particle | grains of 125 micrometers or less shall be 40 mass% or more about the whole shaping | molding particle | grains including not only an iron ore and a carbonaceous material but CaO type | system | group auxiliary material, and 70 mass% or more is more preferable.

  As the sintering machine, it is preferable to use a downward suction type endless moving type sintering machine as in the first and second embodiments. Specifically, pseudo-particles and compression-molded bodies, which are granulated products of granulated sintered raw materials, are supplied onto the endless moving type moving great to form a raw material layer and provided in the moving path of the moving great The raw material layer is ignited and sintered by the ignition furnace. A plurality of wind boxes are arranged immediately below the moving grate, and the gas above the raw material layer is sucked downward through each wind box during sintering.

  When the compression-molded body is charged into the sintering machine, it is preferable to charge it in the region of the lower part 3/4 of the raw material layer of the sintering machine. In the region close to the surface of the raw material layer, the temperature during sintering is relatively low and the high temperature holding time is short. Further, since the air permeability is improved by inserting the compression molded body into this region, this tendency becomes more remarkable. As a result, the reduction reaction of the molded body ends in an insufficient state as compared with the lower layer of the packed bed. In order to charge in this way, for example, as shown in FIG. 10, pseudo particles 71 as a granulated product are supplied from above by a conveying means such as a belt conveyor 79 and compressed to an appropriate position in the raw material layer 72. The compression molded body 74 may be supplied from the molded body hopper 77 through a chute 73 whose charging position can be adjusted. In addition, the code | symbol 75 is a bedding ore, 76 is a sintering pallet, 78 is a fixed quantity cut-out apparatus for compression molded objects, 80 is a segregation charging apparatus.

  The mixing ratio of the compression molded body to the granulated product charged into the sintering machine, that is, the mixing ratio of the compression molded body in the raw material layer is preferably 5 to 50 mass% or less. When this mixing ratio exceeds 50 mass%, that is, when the compression-molded product has a ratio higher than the same ratio as the granulated product, air permeability tends to be excessive, and an unfired portion is likely to occur. On the other hand, if it is less than 5 mass%, the effect of mixing and charging the compression molded body is small. Preferably it is 10-50 mass%.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.
In the present embodiment, as in the first to third embodiments, in the production of sintered ore, the raw material layer temperature reaches about 1400 ° C., the residence time of 1200 ° C. or more is lengthened, and direct reduction is controlled. However, for this purpose, iron ore, carbonaceous material, and auxiliary raw materials are charged into the sintering machine as a sintering raw material and fired, and part of the iron ore is reduced by the carbonaceous material. In producing the ore, a part of the iron ore, a part of the carbonaceous material and a part of the auxiliary raw material among the sintered raw materials are mixed uniformly in advance, and then compression-molded to form a compression-molded body, and the rest of the sintered raw material is A granulated product is obtained, and these are mixed and fired.

  In this way, by compressing a part of the iron ore, a part of the carbonaceous material, and a part of the auxiliary raw material among the sintered raw materials, the iron ore and the carbonaceous material are consolidated to increase their contact area. Therefore, the reduction of the sintered ore can be promoted by charging such a compression molded body into the sintering machine as a part of the raw material.

  Further, since the raw material of the compression molded body is densified by compression, the raw material is present more densely than the granulated product even when it becomes a sintered ore. At this time, the portion densified by compression molding is blocked from the outside air, and the oxidation of metallic iron generated by direct reduction is suppressed.

That is, a compression-molded body obtained by compression-molding a part of iron ore, a part of carbonaceous material and a part of auxiliary materials among the sintered raw materials is put into a sintering machine together with the granulated product of the sintered raw materials and subjected to semi-reduction firing. By producing the ore, a high reduction rate and a high metallic iron content are realized. By using such a sintered ore in a blast furnace, the amount of reducing material used (reducing material ratio) in the entire manufacturing process can be reduced as in the first embodiment, and as a result, CO ₂ from the manufacturing process can be reduced. Emissions can also be reduced.

  In this embodiment, from the viewpoint of maintaining good reactivity, the iron ore is preferably a fine iron ore having a particle size of 8 mm or less of 80% or more, as in the third embodiment. Powdered coke having a particle size of 5 mm or less is preferably 80% or more, and more preferably a particle size of 3 mm or less is 80% or more. Moreover, what contains a CaO source is suitable as an auxiliary material, and a limestone and quicklime can be mentioned as a CaO source, for example.

  Also in the present embodiment, as in the third embodiment, the compression molded body is a briquette formed into a predetermined shape by a compression molding means in a roll molding machine, or a plate shape in the roll molding machine, as in the third embodiment. , Which is formed into a sheet or rod shape and then pulverized to a predetermined size, and the crushing strength of a single particle is 39.2 N or more.

Also in this embodiment, as in the third embodiment, the volume of the compression-molded particles is preferably 10 cm ³ or less from the viewpoint of obtaining optimum air permeability and reactivity. Further, when the size of the compression molded body particles is smaller than 0.065 cm ³ , the volume of the compression molded body may be assimilated and melted with the granulated product at the time of firing, and the reduction rate may not be sufficiently increased. Is more preferably 0.065 to 10 cm ³ . Furthermore, favorable air permeability is obtained by setting the width of the thinnest portion of the compression molded body to 8 mm or more and 20 mm or less.

  As in the third embodiment, it is preferable that the iron ore and carbon material as raw materials constituting the compression-molded body have a particle diameter of 125 μm or less as a whole and be 40 mass% or more. Thus, by atomizing the iron ore and the carbonaceous material, the reactivity of the reduction reaction between them increases, and the reduction rate of the iron ore can be further increased. Here, the iron ore and the carbonaceous material having a particle size of 125 μm or less as a whole is 40 mass% or more. The iron ore and the carbonaceous material are not individually composed of iron ore and the carbonaceous material. It means that the sum of the diameters is 40 mass% or more. More preferably, it is 70 mass% or more. Moreover, it is preferable that the particle | grains of 125 micrometers or less shall be 40 mass% or more about the whole shaping | molding particle | grains including not only an iron ore and a carbonaceous material but CaO type | system | group auxiliary material, and 70 mass% or more is more preferable.

  When quicklime is used as a part or all of the CaO source used as an auxiliary material and the compression molded body contains quicklime as an auxiliary material, the compression molded body is preferably molded without using a binder. By using quick lime as a CaO source to be contained in the compression molded body, quick lime functions as a CaO source and also functions as a binder, and a normally used organic binder is not used when producing the compression molded body. Can be molded. Therefore, it is possible to reduce the cost by omitting the binder that is usually used when forming the compression molded body.

  As for the CaO source used as an auxiliary material, it is preferable that the blending amount in the granulated product is larger than the blending amount in the compression molded body. Specifically, it is preferable that the blending amount of the CaO source in the compression molded body is 40 to 70 mass% of the blending amount of the CaO source in the granulated product. The CaO source is usually added to generate a melt necessary for sintering, but the compression molded body in the present invention is compressed so that a reduction reaction occurs effectively between the iron ore and the carbonaceous material. Therefore, the amount of CaO source does not have to be as large as the remaining granulated product, and 40 to 70 mass% of the CaO source blending amount contained in the remaining granulated product is sufficient. And even if the CaO source blending amount of the compression molded body is reduced in this way, the quality of the sintered ore is properly maintained, the reduction rate of the compression molded body is rather increased, and the CaO source blending amount is low. Cost can be reduced.

The blending amount of the CaO-based auxiliary material in the compression-molded body is preferably such that the CaO / SiO ₂ in the compacting body excluding ignition loss is 1 or more. This effectively functions as an aggregate for maintaining the strength of the compression molded body with CaO-based auxiliary raw materials or as a molten structure of sintered ore to prevent the formation of irreducible FeO-SiO ₂ slag. It can be demonstrated.

The composition of the core part of the granulated product and the composition of the compression-molded product are preferably those in which the carbonaceous material as the reducing material is 10 to 20% by mass relative to 100% by mass of the iron ore and the auxiliary material. The content of the auxiliary material is preferably blended so that the basicity (CaO / SiO ₂ ) of the core portion is 1 or more. Specifically, it is preferably 4 to 10% by mass. The core part of the granulated material may be a single layer or, for example, may have a two-layer structure in which an outer layer made of iron ore is formed on the outer side of an inner layer made of iron ore, auxiliary material and carbonaceous material. Good. The granulated material is constituted by coating the carbon material as a fuel (condensation material) on the outside of the core portion. Moreover, you may use the thing by which the carbon material was coat | covered outside as a compression molding body. The carbon material to be coated is preferably 1 to 4% by mass with respect to 100% by mass in total of iron ore and auxiliary materials.

  Here, if the amount of the carbon material in the core portion is 10 to 20% by mass with respect to 100% by mass of the iron ore and the auxiliary raw material, the iron ore in the pseudo particles can be effectively reduced within this range. Moreover, it is because unreacted coke hardly remains. Moreover, sintering of iron ore can be appropriately advanced by setting the amount of carbonaceous material to be sheathed on the core portion to 1 to 4% by mass with respect to 100% by mass of iron ore and auxiliary raw materials in total.

  As the sintering machine, as in the first to third embodiments, it is preferable to use a downward suction type endless moving type sintering machine. Specifically, pseudo-particles and compression-molded bodies, which are granulated products of granulated sintered raw materials, are supplied onto the endless moving type moving great to form a raw material layer and provided in the moving path of the moving great The raw material layer is ignited and sintered by the ignition furnace. A plurality of wind boxes are arranged immediately below the moving grate, and the gas above the raw material layer is sucked downward through each wind box during sintering.

  The sintering raw material may be charged into the sintering machine after mixing the compression molded body and the granulated product, or both may be charged separately and mixed when forming the raw material layer. May be. In the case of giving a distribution to the charging of the compression molded body, for example, it is preferable to separately load using the above-described apparatus of FIG.

  When the compression-molded body is charged into the sintering machine, it is preferable to charge it in the region of the lower part 3/4 of the raw material layer of the sintering machine. In the region close to the surface of the raw material layer, the temperature during sintering is relatively low and the high temperature holding time is short. Further, since the air permeability is improved by inserting the compression molded body into this region, this tendency becomes more remarkable. As a result, the reduction reaction of the molded body ends in an insufficient state as compared with the lower layer of the packed bed.

  The mixing ratio of the compression molded body to the granulated product charged into the sintering machine, that is, the mixing ratio of the compression molded body in the raw material layer is preferably 5 to 50 mass% or less. When this mixing ratio exceeds 50 mass%, that is, when the compression-molded product has a ratio higher than the same ratio as the granulated product, air permeability tends to be excessive, and an unfired portion is likely to occur. On the other hand, if it is less than 5 mass%, the effect of mixing and charging the compression molded body is small. Preferably it is 10-50 mass%.

Examples of the present invention will be described below in comparison with comparative examples.
1. First Example The first example corresponds to the first embodiment, and corresponds to the following Comparative Example 1, Examples 1-4, Comparative Example 2, and Examples 5-9.

(Comparative Example 1)
Fine iron ore having a particle size of 8 mm or less, an average particle size of 2.3 mm, and a SiO ₂ content of 3.5 mass%, recycled dust, serpentine with a particle size of 3 mm or less, limestone with a particle size of 5 mm or less, quick lime as a binder, After mixing 3 minutes while humidifying with a drum mixer, 3 minutes after mixing the sintered mixed raw material in which 4.4 mass% of powder coke is added to the raw material containing 5 mm or less of sieving sintered powder in the ratio of Table 1 The granulated normal quasi-particles having an average particle size of 4.0 mm were charged into a test batch-type firing furnace having a diameter of 300 mm so as to have a constant layer thickness. Here, blast furnace dust, mill scale, and in-house collection were used as recycled dust (the same applies to the following examples). The average particle size is an arithmetic average particle size based on mass (the same applies to the following examples). The arithmetic average particle diameter D is determined when particles are classified into a plurality of particle diameter ranges, the representative particle diameter (intermediate value of each particle diameter range) is d, and the total mass of the particles in each particle diameter range is W. Can be represented by the following formula.
D = Σ (W · d) / ΣW

  The amount of pseudo particles charged was 45 kg. The surface of the filled raw material layer was ignited with an ignition burner using propane gas as a fuel for 2 minutes while sucking the firing furnace at an exhaust air pressure of 2 kPa, and then the exhaust air pressure was increased to 10 kPa to produce sintered ore. The components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. As shown in these figures, the production rate, the product yield of 5 mm or more, and the shutter strength were within the allowable range, but the obtained sintered ore contained no metallic Fe.

Example 1
Powder iron ore with a particle size of 8 mm or less and an average particle size of 2.3 mm and a carbon material (powder coke) with an external number of 10 mass% with respect to the powder iron ore are mixed for 3 minutes while humidifying with a drum mixer, and then the diameter φ1300 mm After granulating for 5 minutes with a disk pelletizer having a depth of 150 mm, the particles were passed through a sieve having an opening of 5 mm to produce particles for producing reduced iron having a diameter of 5 to 12 mm. 13.5 kg of this reduced iron production particle and 31.5 kg of pseudo particles produced under the same conditions as in Comparative Example 1 were mixed for 1 minute with a drum mixer, and then fixed in the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1 The layer thickness was charged and fired under the same conditions. As in Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. As shown in these figures, the obtained sintered ore had a high Fe content of 8.5 mass%, a production rate of 5 mm or more, a product yield, and a good shutter strength.

(Example 2)
Same as Comparative Example 1 and 13.5 kg of reduced iron manufacturing particles manufactured by the same method as in Example 1 except that the amount of carbonaceous material in the reduced iron manufacturing particles was 15 mass% in terms of the external number with respect to fine iron ore. After mixing 31.5 kg of pseudo-particles produced under the same conditions as in Example 1, the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1 was charged so as to have a constant layer thickness and fired under the same conditions. . As in Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. As shown in these figures, the obtained sintered ore had a high metal Fe content of 15.5 mass%, a production rate of 5 mm or more, a product yield, and a good shutter strength.

(Example 3)
Same as Comparative Example 1 and 13.5 kg of reduced iron manufacturing particles manufactured by the same method as in Example 1 except that the amount of carbonaceous material of the reduced iron manufacturing particles is 20 mass% in terms of the external number with respect to fine iron ore. After mixing 31.5 kg of pseudo-particles produced under the same conditions as in Example 1, the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1 was charged so as to have a constant layer thickness and fired under the same conditions. . As in Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. In this case, the content of metal Fe was as high as 19.7 mass%, but a partially overmelted state was observed around the particles for producing reduced iron, so the production rate was slightly as 1.41 t / m ² / h. Declined. The product yield of 5 mm or more and the shutter strength were good.

Example 4
Same as Comparative Example 1 and 13.5 kg of reduced iron manufacturing particles manufactured by the same method as in Example 1 except that the amount of carbonaceous material in the reduced iron manufacturing particles is 5 mass% in terms of the external number with respect to fine iron ore. After mixing 31.5 kg of pseudo-particles produced under the same conditions as in Example 1, the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1 was charged so as to have a constant layer thickness and fired under the same conditions. . As in Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. In this case, the metal Fe content was 0.8 mass%, lower than that of the other examples in which metal Fe was obtained, and the effect of reducing the blast furnace reducing material ratio was smaller than that of the other examples. Although the production rate was high, the product yield of 5 mm or more and the shutter strength were lower than those of other examples.

(Comparative Example 2)
The diameter which used only the particle for reduced iron manufacture manufactured by the same method as Example 1 in comparative example 1 except having made the carbonaceous compounding quantity of the particle for reduced iron manufacture into 20 mass% by the external number with respect to fine iron ore. The batch-type firing furnace with a diameter of 300 mm was charged so as to have a constant layer thickness and fired under the same conditions. As in Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. In this case, although the metal Fe content was as high as 23.2 mass%, overmelting was remarkable 3 to 5 cm below the upper part of the batch firing furnace, and a large amount of unsintered particles remained from the middle layer to the lower layer. The yield of products with a production rate of 5 mm or more was significantly reduced.

(Example 5)
Reduced iron production particles 13 produced by the same method as Example 1 except that the composition of the reduced iron production particles was 6 mass% quick lime and 15 mass% carbonaceous material with respect to the powdered iron ore. After mixing 31.5 kg of pseudo-particles manufactured under the same conditions as in Comparative Example 1 in the same manner as in Example 1, a constant layer thickness was obtained in the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1. Charged and fired under the same conditions. As in Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. As shown in these figures, the obtained sintered ore had a high content of metal Fe of 17.9 mass%, the production rate, the product yield of 5 mm or more was an acceptable range, and the shutter strength was good.

(Example 6)
After blending limestone with a particle size of 5 mm or less and powdery material with a mass of 15 mass% or less with respect to the powdered iron ore, and mixing for 5 minutes while adding starch and water with a Henschel mixer, 16.2 mm × A briquette having a volume of 1 cm ³ was produced with a molding load of 20 t using a double roll molding machine having a diameter of 400 mm obtained by cutting an almond cup of 12 mm × 8.8 mm, and this was used as particles for producing reduced iron. After mixing 13.5 kg of the particles for producing reduced iron and 31.5 kg of pseudo particles produced under the same conditions as in Comparative Example 1 in the same manner as in Example 1, the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1 was used. It charged so that it might become a fixed layer thickness, and baked on the same conditions. As in Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. As shown in these figures, the obtained sintered ore had a high metal Fe content of 21.2 mass%, a production rate of 5 mm or more, a product yield, and a good shutter strength. In particular, the shutter intensity showed the highest value.

(Example 7)
Same as Example 1 except that the mixture of quick lime of the particles for producing reduced iron is 3.8 mass% with respect to the powdered iron ore and the amount of the carbonaceous material is 15 mass% with respect to the powdered iron ore. After mixing, the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1 was charged so as to have a constant layer thickness and fired under the same conditions. Only the particles for producing reduced iron produced by the same method were charged into the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1 so as to have a constant layer thickness and fired under the same conditions. Similar to Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. As shown in these figures, the obtained sintered ore had a metal Fe content of 5.2 mass%. The production rate, the product yield of 5 mm or more, and the shutter strength all showed slightly low values. Moreover, the trace which was melt | dissolved excessively was recognized by the obtained sintered ore.

(Example 8)
Same as Comparative Example 1 and 20.0 kg of reduced iron production particles produced by the same method as in Example 1 except that the amount of carbonaceous material in the reduced iron production particles was 5 mass% in terms of the external number with respect to fine iron ore. After mixing 25.0 kg of pseudo-particles produced under the same conditions as in Example 1, the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1 was charged so as to have a constant layer thickness and fired under the same conditions. . As in Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. As shown in these figures, the obtained sintered ore had a metal Fe content of 2.2 mass%. Moreover, the production rate, the product yield of 5 mm or more, and the shutter strength were good.

Example 9
Same as Comparative Example 1 and 2.4 kg of reduced iron production particles produced by the same method as in Example 1 except that the carbonaceous material content of the reduced iron production particles was 20 mass% in terms of the external number with respect to fine iron ore. After mixing 42.6 kg of pseudo-particles produced under the same conditions as in Example 1, the batch-type firing furnace having a diameter of 300 mm used in Comparative Example 1 was charged to have a constant layer thickness and fired under the same conditions. . As in Comparative Example 1, the components of the sintered ore at this time are shown in Table 2, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 3. In this case, although the metal Fe content was 3.2 mass% and a partially overmelted state was seen around the reductive production particles, the production rate was 5 mm or more, the product yield was high, and the shutter strength was good. .

From the above, in the examples within the scope of the present invention, the obtained sintered ore was partially reduced and contained metallic Fe. Therefore, when these sintered ores are used in a blast furnace, as described above, a reducing agent ratio reduction and CO ₂ reduction effect in the blast furnace can be obtained. In addition, it was confirmed that a production rate, a yield, and shutter intensity | strength are more than the same level as a normal sintered ore (comparative example 1).

2. Second Example The second example corresponds to the second embodiment, and the following Comparative Example 11, Examples 11 to 14, Comparative Example 12, Example 15, and Comparative Examples 13 and 14 are provided. Applicable.

(Comparative Example 11)
Fine iron ore containing particles with a particle size of 8 mm or less, an average particle size of 2.3 mm, and SiO ₂ containing 3.5 mass%, recycled powder such as blast furnace dust and mill scale, serpentine with a particle size of 3 mm or less, limestone with a particle size of 5 mm or less Baked by adding quick lime as a granulating binder and under-sieving sintered powder of 5 mm or less in a ratio of Table 4 to a raw material containing 45 mass% of particles of 125 μm or less and an external mass of 4.0 mass% of coke breeze The mixed raw materials are mixed for 3 minutes while being humidified with a drum mixer, and then the normal pseudo particles having an average particle diameter of 4.0 mm, which are granulated for 3 minutes, are placed in a batch-type firing furnace for testing with a diameter of 300 mm so as to have a constant layer thickness. I was charged. The amount of pseudo particles charged was 45 kg in terms of dry weight. The surface of the filled raw material layer was ignited with an ignition burner using propane gas as a fuel for 2 minutes while sucking the firing furnace at an exhaust air pressure of 2 kPa, and then the exhaust air pressure was increased to 10 kPa to produce sintered ore. The components of the sintered ore at this time are shown in Table 5, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 6. As shown in these figures, the production rate, product yield of 10 mm or more, and the shutter strength were within the allowable range, but the obtained sintered ore contained no metallic Fe.

(Example 11)
Add 15% by mass of coke breeze to the same fine iron ore, mix for 3 minutes while adding water with a drum mixer, and then add 40 mass% concentrated pregelatinized starch aqueous solution as a binder with a mixer having a stirring screw. The mixture was mixed for 2 minutes, and almond briquette particles having a length of 35 mm × width of 25 mm × thickness of 16 mm were produced while applying a molding pressure of 1470 kN / m with a double roll molding machine. The briquette particles were mixed with the pseudo particles produced in Comparative Example 11 so as to have an inner mass of 10 mass%, and then fired in the same manner as in Comparative Example 11 using 40 kg as a sample. The components of the sintered ore at this time are shown in Table 5, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 6. As shown in these figures, the obtained sintered ore had a metal Fe content of 3.4 mass%, a production rate of 10 mm or more, a product yield, and a good shutter strength.

(Example 12)
In Comparative Example 11, briquette particles were produced in the same manner as in Example 11 except that the amount of powder coke blended was 20 mass% with respect to the powdered iron ore, and the briquette particles were 10 mass% in number. After mixing with the manufactured pseudo particles, 40 kg was used as a sample and fired in the same manner as in Comparative Example 11. The components of the sintered ore at this time are shown in Table 5, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 6. As shown in these figures, the obtained sintered ore had a metal Fe content of 5.6 mass%, a production rate of 10 mm or more of product yield, and a good shutter strength.

(Example 13)
The sintered ore was produced by firing in the same manner as in Example 12 except that the blending amount of briquette particles was 5 mass%. The components of the sintered ore at this time are shown in Table 5, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 6. As shown in these figures, the obtained sintered ore had a metal Fe content of 3.0 mass%, a production rate of 10 mm or more, a product yield, and a good shutter strength.

(Example 14)
A briquette was produced by the same method as in Example 11 except that the size of the briquette particles was 19 mm × 14 mm × 8 mm, and the briquette particles were mixed with the pseudo particles produced in Comparative Example 11 so that the inner number was 30 mass%. After that, it was fired in the same manner as in Example 11. The components of the sintered ore at this time are shown in Table 5, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 6. As shown in these figures, the obtained sintered ore had a metal Fe content of 10.2 mass%, a production rate of 10 mm or more, a product yield, and a good shutter strength.

(Example 15)
Briquette particles were produced in the same manner as in Example 12 except that the amount of powder coke added to briquette particles was 25 mass%, mixed with pseudo particles, and fired in the same manner as in Example 12. The components of the sintered ore at this time are shown in Table 5, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 6. In this case, the briquette melted to a considerable extent, but the metal Fe content was 2.1 mass%.

(Example 16)
Briquette particles were produced in the same manner as in Example 11 except that 20 mass% of powder coke was added to the raw material obtained by mixing 6.0 mass% of quick lime as a binder and CaO source with respect to the powdered iron ore. Was mixed with the pseudo-particles produced in Comparative Example 11 so that the inner volume was 10 mass%, and then 40 kg was used as a sample and fired in the same manner as in Comparative Example 11. The components of the sintered ore at this time are shown in Table 5, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 6. As shown in these figures, the obtained sintered ore had a metal Fe content of 7.3 mass%, a production rate of 10 mm or more, a product yield, and a good shutter strength.

(Example 17)
Briquette particles were produced in the same manner as in Example 11, except that 20 mass% of powder coke was blended into the raw material obtained by mixing 2.0 mass% of quicklime as a binder and CaO source with respect to the powdered iron ore. Was mixed with the pseudo-particles produced in Comparative Example 11 so that the inner volume was 10 mass%, and then 40 kg was used as a sample and fired in the same manner as in Comparative Example 11. The components of the sintered ore at this time are shown in Table 5, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 6. As shown in these figures, the obtained sintered ore had a metal Fe content of 4.8 mass%, a production rate of 10 mm or more, a product yield, and a shutter strength within an allowable range.

(Example 18)
A briquette was produced in the same manner as in Example 11 except that the briquette particle was made into a spherical shape having a diameter of 5 mm, and this briquette particle was mixed with the pseudo particle produced in Comparative Example 11 so that the inner number was 50 mass%. Firing was carried out in the same manner as in Example 11. The components of the sintered ore at this time are shown in Table 5, and the results of measuring the production rate, the product yield of 5 mm or more, and the shutter strength are shown in Table 6. As shown in these figures, the obtained sintered ore has a metal Fe content of 3.8 mass%, and the sintered ore after firing also shows vacancies that are thought to have been caused by excessive melting of briquettes. It was. Further, the production rate, the product yield of 10 mm or more, and the shutter strength were within the allowable range.

From the above, in the examples within the scope of the present invention, the obtained sintered ore was partially reduced and contained metallic Fe. Therefore, when these sintered ores are used in a blast furnace, as described above, a reducing agent ratio reduction and CO ₂ reduction effect in the blast furnace can be obtained. In addition, it was confirmed that a production rate, a yield, and shutter intensity | strength are more than the same level as a normal sintered ore (comparative example 11).

3. Third Example The third example corresponds to the third embodiment described above. Here, pellet feed is used as iron ore, limestone and quicklime are used as CaO-based auxiliary materials, and powder is used as a carbonaceous material. Coke was used. These compositions are shown in Table 7.

  A granulated product and a compression molded product were produced using the sintered raw material. Tables 8 and 9 show the raw material composition of the core part of the granulated product and the raw material composition of the compression molded body, respectively. In addition, as a granulated material, the thing which coat | covered the powder coke so that it might become 3 mass% of a charging raw material as a coagulant | flour outside the core part shown in Table 8 was used. Moreover, as a compression molding body, the thing of the dimension and volume as shown to A, B, and C of Table 10 was used.

  The sintering pot test was done using these granulated material and compression molding. In the sintering pot test, the raw material was pretreated under the same mixing and granulation conditions, and the raw material packed layer was 270 mm in diameter and 300 mm in height, and the suction negative pressure was 6 kPa. The results are shown in Table 11.

  Comparative example 21 among Table 11 is a case where a sintered ore is manufactured using only a granulated material, without using a compression molding. Example 21 adds 33 mass% of the compression molded body shown in A of Table 10 as a sintering machine charging raw material to the sintering raw material composition of Comparative Example 21, and charges the entire sintering raw material packed bed. Is fired. The production rate and product yield are the same as in Comparative Example 21, and the reduction rate of the granulated part is 40%, which is equivalent to that of Comparative Example 21, but the reduction rate of the compression molded part is as high as 60%. The reduction rate of the whole ore was 47%, which was a value significantly higher than that of Comparative Example 21.

  Example 22 is a case where the compression-molded body was charged into the lower 3/4 in the sintered raw material packed layer and fired as compared with Example 21. The production rate and product yield are equivalent to those of Comparative Example 21 and Example 21, and the reduction rate of the granulated part is 40%, which is equivalent to that of Comparative Example 21 and Example 21, but the reduction rate of the compression molded part. Was 67%, and the reduction rate of the entire sintered ore was 49%, which was significantly higher than that of Comparative Example 21.

Example 23 is a case where the size of the compression-molded body is enlarged from Example 22 to B in Table 10. The increase in the size of the compression-molded body improved the air permeability of the packed layer at the time of firing, and although the product yield deteriorated, the production rate was improved to 1.2 T / m ² / hr by shortening the firing time. Moreover, the reduction rate of the compression molded body portion was high, and the reduction rate of the entire sintered ore was 47%, which was also significantly higher than that of Comparative Example 21.

  Example 24 is a case where, compared with Example 23, the compression molded body was charged in the lower half in the sintered raw material packed layer and fired. The production rate and product yield are the same as in Comparative Example 21, and the reduction rate of the granulated part is 40%, which is equivalent to that of Comparative Example 21, but the reduction rate of the compression molded part is as high as 69%, and sintering The reduction rate of the entire ore was 50%, which was significantly higher than that of Comparative Example 21.

  Example 25 is a case where 50% by mass of the compression molded body as a raw material charged in the sintering machine was added to Example 23 and fired. The production rate and product yield are the same as in Comparative Example 21, and the reduction rate of the granulated part is 40%, which is equivalent to that of Comparative Example 21, but the reduction rate of the compression molded part is as high as 60%. The reduction rate of the entire ore was 50%, which was significantly higher than that of Comparative Example 21.

  Example 26 is a case where the content of the compression-molded body is changed to 4 mass% of the whole raw materials charged in the sintering machine and fired with respect to Example 23. The production rate and product yield were the same as in Comparative Example 21. The reduction ratio of the entire sintered ore was 41%, which was lower than that in Example 23, but was slightly higher than that in Comparative Example 21.

  Example 27 is a case where the content of the compression-molded body was changed to 55 mass% of the whole raw material charged in the sintering machine, compared to Example 23. The product yield was equivalent to that of Comparative Example 21, and the production rate was higher than that of Comparative Example 21. However, the air permeability was excessively increased, the reduction rate of the compression molded product was lowered, and the reduction rate of the entire sintered ore was 46%, which was higher than that of Comparative Example 21, but lower than that of Example 23.

  Example 28 is a case where the size of the compression-molded body was reduced with respect to Example 23 and fired. The production rate and product yield were the same as in Comparative Example 21. However, there was a tendency for the firing to become unstable, and the reduction rate of the entire sintered ore was 44%, which was higher than that of Comparative Example 21, but lower than that of Example 23.

Example 29 is a case where the CaO / SiO ₂ value of the compression-molded particles was reduced to 0.9 as compared to Example 23. The production rate and product yield were the same as in Comparative Example 21. However, since CaO / SiO ₂ was low, the reduction rate of the compression molded product was reduced, and the reduction rate of the entire sintered ore was 43%, which was slightly higher than that of Comparative Example 21, but lower than that of Example 23.

4). Fourth Example The fourth example corresponds to the above fourth embodiment. Here, pellet feed is used as iron ore, limestone and quicklime are used as CaO-based auxiliary materials, and powder is used as a carbonaceous material. Coke was used. These compositions are shown in Table 12.

  A granulated product and a compression molded product were produced using the sintered raw material. Table 13 shows the raw material composition of the core part of the granulated product and the raw material composition of the compression molded body. In addition, as a granulated material, the thing which coat | covered the powder coke so that it might become 3 mass% of a charging raw material as a coagulant | flour outside the core part shown in Table 2 was used. In addition, a compression molded body having a size and volume as shown in Table 14 was used.

  The sintering pot test was done using these granulated material and compression molding. In the sintering pot test, the raw material was pretreated under the same mixing and granulation conditions, and the raw material packed layer was 270 mm in diameter and 300 mm in height, and the suction negative pressure was 6 kPa. Table 15 shows the composition and characteristics of the compression molded product, and Table 16 shows the test results.

  In Tables 15 and 16, Examples 31 and 32 were obtained by adding 33 mass% of the compression molded body as a raw material charged in the sintering machine, Example 31 used limestone as a CaO source, and Example 32 used quick lime. It was. Further, in both Examples 31 and 32, the Fe / CaO value of the compression-molded product is the same as that of the granulated product, and 1.4 mass% of starch is added as a binder. The crushing strength and the drop strength of the compression-molded body are higher in Example 32 than in Example 31, and as a result of performing a firing test by mixing with the granulated product, the production rate, product yield, and reduction rate were implemented. Example 31 and Example 32 were equivalent.

  Example 33 is a case in which quick binder lime having a binder effect is blended instead of starch as a binder and limestone as a CaO source for Example 31, and starch as a binder for Example 32. Is not added, and is within the scope of the present invention. The crushing strength and drop strength of the compression molded product were lower than in Example 32, but were equivalent to Example 31. In addition, as a result of performing the firing test by mixing with the granulated product, the production rate and the product yield are the same as in Example 31, and the reduction rate is slightly lower than that in Example 31 and is at a level that is not a problem. It was.

  Example 34 is a case where a fine raw material was used as a blending raw material with respect to Example 31, and the ratio of the particle size of 125 μm or less with respect to the mixed raw material was 75 mass% with respect to 55 mass% of Example 31. The crushing strength and drop strength of the finished product were lower than those of Example 31, but there was no problem when handling. In addition, as a result of performing the firing test by mixing with the granulated product, the production rate and the product yield were the same as in Example 31, but the reduction rate of the compression molded part was 68%. Improved from 60%.

  Example 35 is a formulation in which CaO is reduced with respect to Example 31, and Fe / CaO is 0.7 with respect to Example 31 and is within the scope of the present invention. As a result of carrying out the firing test by mixing with the granulated product, the production rate and product yield are the same as in Example 31, but the reduction rate of the compression molded part is 65%, which is 60% of Example 31. More improved.

  Example 36 is a formulation in which CaO is reduced with respect to Example 31, and Fe / CaO is 0.4 with respect to Example 31 and is within the scope of the present invention. As a result of carrying out the firing test by mixing with the granulated product, the production rate and product yield are the same as in Example 31, but the reduction rate of the compression molded part is 63%, which is 60% of Example 31. More improved.

  Example 37 is a formulation in which CaO is reduced with respect to Example 32, and Fe / CaO is 0.7 with respect to Example 32, and is within the scope of the present invention. As a result of carrying out the firing test by mixing with the granulated product, the production rate and product yield are the same as in Example 32, but the reduction rate of the compression molded part is 68%, 62% of Example 32. More improved.

  Example 38 is a formulation in which CaO is reduced with respect to Example 32, and Fe / CaO is 0.4 with respect to Example 32, and is within the scope of the present invention. As a result of carrying out the firing test by mixing with the granulated product, the production rate and product yield are the same as in Example 32, but the reduction rate of the compression molded part is 65%, 62% of Example 32. More improved.

  Example 39 is a case where iron ore powder of 3 mm or less is used as a raw material of the compression molded body in place of the pellet feed of Examples 31 and 32. The production rate and product yield were similar to those in Examples 31 and 32, but the reduction rate of the compression molded part was 48%, which was lower than in Examples 31 and 32.

  Example 40 is a case where the iron ore powder was pulverized before mixing to 1 mm or less with respect to Example 39, and the ratio of 125 μm or less in the entire mixed raw material was 40 mass%, which is within the scope of the present invention. As a result of carrying out the firing test by mixing with the granulated product, the production rate and product yield are the same as in Example 39, but the reduction rate of the compression molded part is 56%, 48% of Example 39. More improved.

  Example 41 is a case where the iron ore powder is pulverized to 1 mm or less before mixing with respect to Example 39, and the ratio of 125 μm or less in the entire mixed raw material is 58 mass%, and is within the scope of the present invention. As a result of carrying out the firing test by mixing with the granulated product, the production rate and product yield are the same as in Example 39, but the reduction rate of the compression molded part is 62%, 48% of Example 39. More improved.

In Example 42, the CaO / SiO ₂ of the compression molded body portion of Example 34 was changed to 1.1. The production rate and product yield were the same as in Example 34, but the reduction rate of the compression molded part was 55%, which was lower than in Example 34.

The figure which shows the relationship between the reduction rate of a sintered ore, and a blast furnace reducing material ratio. The relationship between the average reduction rate of sinter during blast furnace charging and the amount of C discharged from the ironmaking process was compared between the sinter with uniform partial reduction and the sinter with the preferential generation of metallic Fe. FIG. Figure showing the relationship between the reduction rate during sintering and the content of metallic iron after sintering in the case of pseudo particles by rolling granulation and the case of briquette particles The schematic diagram which shows an example of the equipment for enforcing the manufacturing method of the semi-reduction sintered ore which concerns on the 1st Embodiment of this invention. The schematic diagram which shows the structure of the raw material layer in the manufacturing method of the semi-reduction sintered ore which concerns on the 1st Embodiment of this invention. The schematic diagram for demonstrating the state of the shaping | molding particle | grains during sintering in the manufacturing method of the semi-reduction sintered ore which concerns on the 2nd Embodiment of this invention. The figure which shows the relationship between the shaping | molding pressure of a shaping | molding particle, and the yield of +5 mm after a drop test. The schematic diagram which shows an example of the equipment for enforcing the manufacturing method of the semi-reduction sintered ore which concerns on the 2nd Embodiment of this invention. The schematic diagram which shows the structure of the raw material layer in the manufacturing method of the semi-reduction sintered ore which concerns on the 2nd Embodiment of this invention. The figure for demonstrating an example of the charging method of the sintering raw material in the manufacturing method of the semi-reduction sintered ore which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

1 Raw material source for pseudo particles 2 Rolling granulator 3 Raw material source for particles for producing reduced iron 4 Molding device 5 Mixer 6 Hopper 10 Roll feeder 11 Moving grate 12 Ignition furnace 13 Raw material layer 14 Conveyor 15 Wind box 16 Vertical duct 17 Main exhaust duct 20 Electric dust collector 21 Main blower 22 Chimney 31 Matrix of normal pseudo particles 32 Reduced iron production particles 40 Raw material production equipment 50 Downward suction type endless moving type sintering machine 61 Sintered packed bed (raw material layer)
62 Pseudoparticles 63 Molded particles 64 Film 71 Pseudoparticles 72 Raw material layer 73 Chute 74 Compression molded body 75 Floor bedding 76 Sintered pallet 77 Compression molded body hopper 78 Compression molded body quantitative cutting device 79 Belt conveyor 100 Molded particle production Equipment 200 Pseudoparticle Production Equipment 300 Downward Suction Type Endless Moving Sintering Machine 331 Pseudoparticle Matrix 332 Molded Particle

Claims (13)

Using iron ore, carbonaceous material and CaO-based auxiliary materials as sintering raw materials, charging the sintering raw materials into a sintering machine to form a raw material layer, firing this raw material layer, and part of the iron ore Is a reduced semi-reduced sintered ore,
A mixed powder in which the mass ratio of the iron ore or a component excluding the ignition loss of the reduced iron production for particle CaO / SiO ₂ was added CaO-based auxiliary raw material iron ore to be 1 or more, the iron ore or the mixture a plurality of reduced iron production for particles obtained by molding and 5 mass% or more of carbonaceous material outside number relative to flour is, as part of the sintering raw material, constitute 5～50Mass% of the raw material layer, wherein The volume per particle of the reduced iron production particle is 10 cm ³ or less, a part of the iron ore is reduced by firing, and the average value of the entire sintered ore contains 3 mass% or more of metal Fe. A semi-reduced sintered ore that is characterized. An iron ore and carbonaceous material and a CaO-based auxiliary raw material as raw material to be sintered, and charged with sintering material on sintering machine constitutes a raw material layer, a half of claim 1 by firing the raw material layer A method for producing a reduced sintered ore, comprising:
Part of the sintered raw material, a plurality of particles for producing reduced iron having a volume of 10 cm ³ or less, each of which is formed by molding iron ore and carbon material of 5 mass% or more with respect to iron ore. As described above, a part of the iron ore is reduced by mixing and firing so as to be 5 to 50 mass% of the raw material layer, and a semi-reduction containing 3 mass% or more of metal Fe as an average value of the entire sintered ore A method for producing a semi-reduced sintered ore characterized in that it is a sintered ore. An iron ore and carbonaceous material and a CaO-based auxiliary raw material as raw material to be sintered, and charged with sintering material on sintering machine constitutes a raw material layer, a half of claim 1 by firing the raw material layer A method for producing a reduced sintered ore, comprising:
A plurality of particles for producing reduced iron having a volume of 10 cm ³ or less per mixed powder obtained by adding CaO-based auxiliary materials to iron ore and a carbon material having an external number of 5 mass% or more with respect to the mixed powder In this case, the CaO-based auxiliary material is a component excluding the loss of ignition of the reduced iron production particles so that the mass ratio of CaO / SiO ₂ is 1 or more, and these reduced iron production particles are As a part of the sintered raw material, a part of the iron ore is reduced by mixing and firing so as to be 5 to 50 mass% of the raw material layer, and the average value of the entire sintered ore is 3 mass% or more. A method for producing a semi-reduced sintered ore comprising a metal Fe-containing semi-reduced sintered ore. The semi-reduced sintered ore according to claim 2 or 3 , wherein the particles for producing reduced iron are those obtained by compression-molding a raw material by a roll molding machine or rolling granulation of the raw material. Manufacturing method. An iron ore and carbonaceous material and a CaO-based auxiliary raw material as raw material to be sintered, and charged with sintering material on sintering machine constitutes a raw material layer, a half of claim 1 by firing the raw material layer A method for producing a reduced sintered ore, comprising:
Blended and 10～20Mass% of carbonaceous material outside number against iron ore and iron ore, the addition of more binder and mixed if necessary with water, the mixture was compression-molded by a roll forming machine, 1 A plurality of particles for producing reduced iron having a volume per piece of 10 cm ³ or less, and the particles for producing reduced iron are mixed as part of the sintered raw material so as to be 5 to 50 mass% of the raw material layer,
A method for producing a semi-reduced sintered ore characterized in that a part of iron ore is reduced by firing and contains 3 mass% or more of metal Fe as an average value of the entire sintered ore. The method for producing a semi-reduced sintered ore according to claim 5 , wherein the raw material for producing the particles for producing reduced iron is 8 mm or less for iron ore and 5 mm or less for carbonaceous material. The method for producing a semi-reduced sintered ore according to claim 6 , wherein the raw material for producing the particles for producing reduced iron contains 40 mass% or more of particles of 125 μm or less. An iron ore and carbonaceous material and a CaO-based auxiliary raw material as raw material to be sintered, and charged with sintering material on sintering machine constitutes a raw material layer, and firing the raw material layer, a half of claim 1 A method for producing a reduced sintered ore, comprising:
A mixture of iron ore with CaO-based auxiliary material and a mixture of 10 to 20 mass% carbonaceous material with respect to the mixed powder, water and, if necessary, a binder added and mixed, and this mixture is rolled. Compression molding is performed with a molding machine to obtain a plurality of particles for producing reduced iron having a volume of 10 cm ³ or less . In this case, the CaO-based auxiliary material is a component excluding the loss of ignition of the particles for producing reduced iron. Formulated so that CaO / SiO ₂ is 1 or more, and this reduced iron production particle is mixed so as to be 5 to 50 mass% of the raw material layer as a part of the sintered raw material,
A method for producing a semi-reduced sintered ore characterized in that a part of iron ore is reduced by firing and contains 3 mass% or more of metal Fe as an average value of the entire sintered ore. The semi-reduction sintering according to claim 8 , wherein raw materials for producing the particles for producing reduced iron are iron ore of 8 mm or less, carbonaceous material of 5 mm or less, and CaO-based auxiliary material of 5 mm or less. Manufacturing method of ore. The method for producing a semi-reduced sintered ore according to claim 9 , wherein the raw material for producing the particles for producing reduced iron contains 40 mass% or more of particles of 125 µm or less. Particles for producing reduced iron that have been compression-molded by the roll forming machine, a plurality of briquettes formed into a predetermined shape by a roll forming machine, or a predetermined size after being formed into a plate shape, a sheet shape, or a rod shape by a roll forming machine The method for producing a semi-reduced sintered ore according to any one of claims 5 to 10 , wherein a pulverized product is used. The charged particles according to any one of claims 5 to 11, wherein the compression-molded particles for producing reduced iron are charged into a region below 3/4 of the lower part of the raw material layer when charged into a sintering machine. The manufacturing method of the semi-reduced sintered ore as described. Said compression molded iron ore and carbonaceous material as a raw material constituting the reduced iron production for particles according to claim 11 or those having a particle diameter of 125μm or less as a whole they are characterized in that so as to be above 70 mass% The method for producing a semi-reduced sintered ore according to claim 12 .

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