JP6809446B2 - Manufacturing method of carbon material interior particles and manufacturing method of carbon material interior sintered ore - Google Patents

Description

The present invention relates to a technique for producing a sintered ore used as a raw material for iron making in a blast furnace or the like. Specifically, the present invention relates to a method for producing carbonaceous material interior particles containing a carbonaceous material and sintering the carbonaceous material internal particles. The present invention relates to a method for producing a carbonaceous material interior sinter produced as a part of a raw material.

In the blast furnace ironmaking method, sintered ore, iron ore, pellets, etc. are mainly used as iron sources. Here, the sinter is a kind of agglomerate ore and is produced by the following procedure. First, iron-containing raw materials such as iron ore and dust having a particle size of 10 mm or less, auxiliary raw materials containing at least lime-containing raw materials such as limestone, fresh lime, and steelmaking slag, and MgO-containing raw materials such as refined nickel slag, dolomite, and serpentine. An appropriate amount of water is added to a granulation raw material composed of a SiO _2- containing raw material such as iron ore and a coagulant material such as coke breeze and smokeless coal, and the mixture is mixed and granulated using a drum mixer or the like. Let it be a pseudo particle. Next, the granulated raw material made into pseudo particles is charged into a pallet that circulates and moves in the sintering machine, and the coagulant contained in the granulated raw material is burned to obtain a sintered cake. After that, the sintered cake is crushed, cooled, and sized, and those having a certain particle size or larger are recovered as a product sintered ore.

Conventionally, the method of uniformly performing liquid phase sintering of the entire sintered bed has been the mainstream, but in recent years, a part mainly composed of liquid phase sintering and a part in which liquid phase formation is suppressed are mixed in the sintered bed, and it is intentionally made. Sintering methods that aim for non-uniform structures are being studied. The reason for this is that many fine pores remain after sintering in the portion having a high melting point and being difficult to melt, and the portion becomes a sintered ore structure that is easily reduced and has a large contact area with the reducing gas.

As a method for producing such agglomerate ore, Patent Document 1 describes wet pellets in which a carbonaceous material is coated with iron ore powder and a CaO-containing raw material as a method in which liquid phase formation is suppressed at a high melting point. A method of mixing with a sintering raw material mainly composed of liquid phase sintering and then sintering in a downward suction type sintering machine is disclosed.

Japanese Patent No. 5790966

As disclosed in Patent Document 1, in the coal material interior sinter, coal material interior particles having a carbon material core are mixed with ordinary granulated particles having no carbon material core to be used as a sinter raw material and baked. Manufactured by sintering with a knot. However, when the carbonaceous material interior particles granulated by the granulator are transported to the sintering machine and disintegrate in the process of being charged into the sintering machine, a portion in which liquid phase formation is suppressed is not generated and is easily reduced. No sinter is formed. The present invention has been made in view of the above problems, and an object of the present invention is to obtain carbonaceous material interior particles capable of suppressing the collapse of carbonaceous material interior particles in a process of being transported to a sintering machine and charged into the sintering machine. The purpose is to provide a manufacturing method.

The features of the present invention that can solve such a problem are as follows.
(1) A powdery iron-containing raw material, a lime-containing raw material, and an organic binder are mixed to form a mixed powder.
A method for producing carbonaceous material interior particles, wherein the mixed powder and the carbonaceous material are granulated to produce carbonaceous material interior particles in which an outer layer made of the mixed powder is formed around a carbon material core.
(2) The method for producing carbonaceous material interior particles according to (1), wherein the organic binder is any one or more of carboxymethyl cellulose, polyvinyl alcohol, pregelatinized starch and magnesium lignin sulfonate.
(3) The method for producing carbonaceous material interior particles according to (2), wherein the polyvinyl alcohol is polyvinyl alcohol powder.
(4) The method for producing carbonaceous material interior particles according to (3), wherein the polyvinyl alcohol powder is a polyvinyl alcohol powder sieved under a sieve with a 100-mesh sieve.
(5) The carbonaceous material interior according to (3) or (4), wherein the polyvinyl alcohol powder is blended so that the blending ratio of the polyvinyl alcohol powder to the mixed powder is 0.1% by mass or more and 3.0% by mass or less. How to make particles.
(6) The carbonaceous material interior particles produced by the method for producing the carbonaceous material interior particles according to any one of (1) to (5) are mixed with an iron-containing raw material, an auxiliary raw material, and a binder. , A method for producing a carbonaceous interior sinter, which is blended with granulated granules to form a sintering raw material, and the sintering raw material is charged into a pallet of a sintering machine and sintered.

By implementing the method for producing carbon material interior sintered ore of the present invention, it is possible to produce carbon material interior particles having high crushing strength, so that the particles are disintegrated in the process of being transported to the sintering machine and charged into the sintering machine. It is possible to reduce the amount of carbon material interior particles.

It is a schematic diagram which shows an example of the manufacturing process 10 of the carbonaceous material interior particle which can carry out the manufacturing method of the carbonaceous material interior particle which concerns on this embodiment. It is a photograph which shows the mixed powder 30, coke particle 32 (including the growing carbonaceous material interior particle), and carbonaceous material interior particle 40 existing in the granulator 38. It is a schematic diagram which shows an example of the manufacturing process 100 of the coal material interior sintered ore that can carry out the manufacturing method of the coal material interior sintered ore. It is a graph which shows the relationship between the water content ratio of the carbonaceous material interior particle, and crushing strength. It is a graph which shows the relationship between the compounding ratio of polyvinyl alcohol powder, and the crushing strength of carbonaceous material interior particles. It is a graph which shows the RI of the sinter of an Example and a comparative example.

Hereinafter, the present invention will be described through embodiments of the present invention. FIG. 1 is a schematic view showing an example of a carbonaceous material interior particle manufacturing process 10 in which the method for producing carbonaceous material interior particles according to the present embodiment can be carried out. A method for producing the carbonaceous material interior particles according to the present embodiment will be described with reference to FIG.

In the production process 10 of the carbonaceous material interior particles, first, the iron ore powder 12 stored in the storage tank 14, the quicklime 16 stored in the storage tank 18, and the polyvinyl alcohol powder 20 stored in the storage tank 22 are respectively. A predetermined amount is cut out from the storage tank into the transport machine 24. The iron ore powder 12, quicklime 16 and polyvinyl alcohol powder 20 are transported by the transporter 24 to a kneader 28 such as an intensive mixer. The iron ore powder 12, quicklime 16 and polyvinyl alcohol powder 20 are mixed with an appropriate amount of water 26 in the kneader 28 to form a mixed powder 30.

In the present embodiment, the iron ore powder 12 is an example of a powdery iron-containing raw material, for example, iron ore powder having a particle size of 150 μm or less and a specific surface area of about 1500 cm ² / g. Quicklime 16 is an example of a lime-containing raw material, and limestone may be used instead of quicklime or together with quicklime. However, from the viewpoint of granulating the mixed powder 30, it is preferable to use quicklime having a high granulation effect. In addition, dolomite [CaMg (CO ₃ ) ₂ ], which increases the viscosity of the melt produced during sintering, may be added to quicklime and / or limestone. That is, the lime-containing raw material is a raw material containing any one or more of quicklime, limestone and dolomite. The polyvinyl alcohol powder 20 is an example of an organic binder, and as the organic binder, any one or more of carboxymethyl cellulose, polyvinyl alcohol, pregelatinized starch and magnesium lignin sulfonate may be used.

Next, the mixed powder 30 mixed by the kneader 28 and the coke particles 32 stored in the storage tank 34 are cut out in a predetermined amount by the conveyor 36 and used as a raw material for granulation. In the present embodiment, the mixed powder 30 and the coke particles 32 are mixed so that the blending ratio of the coke particles 32 with respect to the granulation raw material is 1% by mass or more and 5% by mass or less, more preferably 2% by mass or more and 4% by mass or less. It is cut out.

In the present embodiment, the coke particles 32 are an example of a carbonaceous material, and the coal material has an outer layer made of a mixed powder 30 formed around the coke material to form a core of the carbon material. Anthracite charcoal, Hongei charcoal, may be used as the charcoal material. Since coke particles and Hongei charcoal have low volatile content, the amount of combustion gas generated from the sinter during sintering can be reduced by using them, and the strength of the sinter inside the sinter produced using the sinter is reduced. Is suppressed. As a result, it is possible to suppress a decrease in the yield of the sinter for the interior of the carbonaceous material.

The granulating raw material is conveyed by the conveying machine 36 to the granulating machine 38 such as a disc pelletizer. The granulation raw material is rolled together with an appropriate amount of water 26 by the granulator 38, and the coke particles 32 become the carbon material core due to the cross-linking force of water or the like, and the outer layer composed of the mixed powder 30 is formed around the coke material interior. Particle 40 is produced.

FIG. 2 is a photograph showing the mixed powder 30, coke particles 32 (including growing carbonaceous material interior particles), and carbonaceous material interior particles 40 existing in the granulator 38. The carbonaceous material internal particles 40 are produced according to the production process 10 of the carbonaceous material internal particles shown in FIG. 1. However, if the strength of the carbon material internal particles 40 is low, the carbon material internal particles 40 are conveyed to the sintering machine and baked. It collapses in the process of being charged into the particle. Therefore, in the method for producing carbonaceous material interior particles according to the present embodiment, polyvinyl alcohol powder 20 is blended with iron ore powder 12 and quicklime 16. As a result, the strength of the mixed powder 30 formed as an outer layer around the coke particles 32 is increased, and it is possible to suppress the collapse of the carbonaceous material interior particles 40 in the process of transporting the mixed powder 30 to the sintering machine and charging the coke particles 32 into the sintering machine. ..

FIG. 3 is a schematic view showing an example of a production process 100 of a carbonaceous interior sintered ore in which a method for producing a carbonaceous interior sintered ore can be carried out. In the production process 100 of the carbon material interior sintered ore, in parallel with the production process 10 of the carbon material interior particles shown in FIG. 1, iron-containing raw materials such as iron ore and dust having a particle size of 10 mm or less, limestone, and fresh lime. , A raw material 50 containing an auxiliary raw material containing a CaO-containing raw material such as steelmaking slag and a coagulant made of powdered coke or smokeless coal having a particle size of less than 3 mm is granulated by a granulator 52 such as a drum mixer. It is a grain size. The auxiliary raw material may include an MgO-containing raw material such as refined nickel slag, dolomite, and serpentinite, and a SiO _2- containing raw material made of silica stone or the like.

Next, the carbonaceous material interior particles 40 are mixed with the granulated particles obtained by granulating the raw material 50 to obtain a sintered raw material. Of the sintering raw materials, the granulated particles obtained by granulating the raw material 50 serve as a portion mainly composed of liquid phase sintering, and the carbonaceous material interior particles 40 serve as a portion in which liquid phase formation is suppressed. It is preferable to add the carbonaceous material interior particles 40 to the granulated particles so that the mixing ratio of the carbonaceous material interior particles 40 with respect to the sintering raw material is 10% by mass or more and 30% by mass or less. As a result, the air permeability of the sinter raw material is improved, and the productivity of the sinter for the interior of the carbonaceous material is improved.

The sintering raw material containing the carbonaceous material interior particles is carried into the surge hopper of the downward suction type sintering machine 60. The sintered raw material is charged from the surge hopper into an endlessly movable pallet to form an charged layer. The charge layer is ignited by an ignition furnace installed above, and the upper gas is sucked downward from the wind box installed below, so that the charge layer is sequentially burned and sintered. The charging layer is sintered by the heat of combustion generated by the combustion to form a sintered cake. The sintered cake is crushed and sized at the sinter part, and agglomerates having a particle size of 4 mm or more are recovered as a sinter for the interior of carbonaceous materials. The carbonaceous interior sintered ore produced in this way is used as a raw material for steelmaking in the blast furnace 70. The particle size in the present embodiment is a particle size sieved using a sieve having a nominal opening according to JIS (Japanese Industrial Standards) Z 8801-1, and for example, a particle size of 4 mm or more is defined as a particle size of 4 mm or more. The particle size that is sieved onto a sieve using a sieve with a nominal opening of 4 mm in accordance with JIS Z 8801-1.

The particle size of the coke particles 32 used in the method for producing the carbonaceous material interior particles according to the present embodiment is preferably 2 mm or more. By using coke particles having a particle size of 2 mm or more, it is possible to prevent the coke particles from disappearing in the step of sintering the sintering raw material containing the carbonaceous material interior particles with a sintering machine. The particle size of the coke particles 32 is more preferably 3 mm or more. By using a carbonaceous material having a particle size of 3 mm or more, the disappearance of coke particles can be further suppressed.

On the other hand, when coke particles having a large particle size are used, the amount of combustion gas generated from coke during sintering increases, and cracks occur in the outer layer covering the coke particles in the carbonaceous material interior sinter. When the outer layer covering the coke particles is cracked, the strength of the carbonaceous interior sinter is greatly reduced, and as a result, the yield of the carbonaceous interior sinter is significantly reduced. Therefore, the particle size of the coke particles 32 is preferably 8 mm or less, and more preferably 6 mm or less.

Further, the particle size of the produced carbonaceous material interior particles 40 is preferably 8 mm or more and 18 mm or less. As described above, the carbonaceous interior sinter having a particle size of 4 mm or more is recovered as a product sinter, and the sinter having a particle size of less than 4 mm is recycled (returned) into a sintering raw material. Further, when the carbonaceous material interior particles 40 are sintered by a sintering machine, the volume becomes smaller due to evaporation of water or partial melting. Therefore, the particle size of the carbonaceous material interior particles 40 is preferably 8 mm or more, and more preferably 10 mm or more so that even if the carbonaceous material interior particles 40 are sintered as they are, they do not return ore.

On the other hand, if the thickness of the outer layer of the coke particles 32 formed on the carbon material inner particles 40 exceeds 5 mm, it becomes difficult to sinter all the outer layers of the carbon material inner particles 40 within a limited sintering time. Become. If a portion of insufficient sintering is present in the sinter for the interior of the carbonaceous material, the strength of the sinter for the interior of the carbonaceous material decreases, and the yield of the sinter for the interior of the carbon material decreases. Therefore, the thickness of the outer layer of the carbonaceous material interior particles 40 is preferably 5 mm or less. For example, the particles of the carbonaceous material interior particles when the particle size of the coke particles 32 is 8 mm and the thickness of the outer layer is 5 mm. The diameter will be 18 mm. Therefore, the particle size of the carbonaceous material interior particles 40 is preferably 18 mm or less.

Further, in the method for producing carbonaceous material interior particles according to the present embodiment, polyvinyl alcohol, which is an organic binder, is used as the binder. Since the organic binder volatilizes due to combustion of the carbonaceous material interior particles 40 during sintering, it does not remain in the coal material internal sintered ore after sintering. Therefore, by using an organic binder, the effect of using the binder on the carbonaceous material interior particles 40 and the carbonaceous material internal firing produced by sintering the sintering raw material containing the carbonaceous material internal particles 40. The impact on sinter can be reduced.

Further, in the method for producing carbonaceous material interior particles according to the present embodiment, an example in which powdered polyvinyl alcohol powder 20 is used as the organic binder is shown. However, it is not limited to the powdery organic binder, and an organic binder solution in which the organic binder is dissolved at a certain concentration may be used.

However, in order to keep the quality of the iron ore interior particles constant, it is required to keep the water content and the binder content of the iron ore interior particles 40 constant. Therefore, tentatively, the organic binder solution is mixed in the stirrer or the granulator. When the raw material containing the iron ore powder 12 is sprayed with, when the water content of the iron ore powder 12 fluctuates, it is necessary to control the binder concentration in the solution according to the water content of the raw material containing the iron ore powder 12. Further, if the concentration of the organic binder solution is different, the viscosity of the organic binder solution is also different, and it is necessary to adjust the spraying conditions of the organic binder solution according to the viscosity.

Therefore, it is preferable to use a powdery binder such as polyvinyl alcohol powder 20 as the binder. By using a powdery binder as the organic binder, the organic binder and the iron ore raw material can be mixed and uniformly mixed without the above-mentioned control. As a result, the strength of the carbonaceous material interior particles 40 is improved on average as a whole, and the quality of the carbonaceous material interior particles 40 can be kept constant.

Further, it is preferable to use polyvinyl alcohol powder sieved under a sieve with a 100 mesh sieve. Since the particle size of the polyvinyl alcohol powder sieved under the sieve with a 100-mesh sieve is 150 μm or less, it is about the same as the particle size of the iron ore powder 12 mixed with the polyvinyl alcohol powder. By making the particle sizes of the polyvinyl alcohol powder and the iron ore powder 12 about the same in this way, segregation due to the difference in particle size can be suppressed and the mixture can be mixed more uniformly, and the quality of the carbonaceous material interior particles 40 can be kept constant. it can.

Next, the strength of the carbonaceous material interior particles 40 will be described. From the time when the carbonaceous material interior particles 40 are manufactured to the time when they are charged into the downward suction type sintering machine 60, the carbon material internal particles 40 transfer to a plurality of conveyors. Therefore, it is preferable that the carbonaceous material interior particles 40 have a strength to withstand the connection between a plurality of conveyors and the impact at the time of loading the pallet of the downward suction type sintering machine 60. First, the carbonaceous interior particles having different crushing strengths were experimentally produced, and the collapse state of the carbonaceous interior particles after the transfer of the conveyor and the pallet loading was confirmed. As a result, by setting the crushing strength of the carbonaceous material interior particles to 9.8 N / piece or more, it can withstand the impact of connecting multiple conveyors and loading the pallet of the downward suction type sintering machine 60, and is a downward suction type. It has been found that direct delivery to the sintering machine 60 is possible. In the present embodiment, the crushing strength is the maximum strength measured by compressing the carbonaceous material interior particles at a compression rate of 1 mm / min using a compression tester.

In order to increase the crushing strength of the carbonaceous interior particles to 9.8 N / piece or more, iron ore powder containing hematite as the main mineral has a Braine specific surface area of about 1800 to 2000 cm ² / g or an iron ore having a particle size of 45 μm or less. It is necessary to use iron ore powder having a stone powder content of 80% by mass or more. However, most of the hematite concentrate fine powder currently distributed in the iron ore market has a Braine specific surface area of about 500 to 1500 cm ² / g and a content ratio of iron ore powder of about 45 μm or less of about 35 to 75% by mass. .. Therefore, even if these raw materials are used as they are, it is not possible to produce carbonaceous material interior particles having a crushing strength of 9.8 N / piece or more.

On the other hand, by crushing the iron ore powder using a ball mill or the like, the content ratio of the iron ore powder having a Braine specific surface area of 1800 cm ² / g or more or a particle size of 45 μm or less can be achieved of 80% by mass or more, but the equipment cost and running can be achieved. The cost is high. Therefore, in order to confirm whether or not the crushing strength of the carbonaceous material interior particles can be increased to 9.8 N / piece or more by blending the polyvinyl alcohol powder 20 with the outer layer mixed powder 30 formed around the carbonaceous material, FIG. The production test of the carbonaceous material interior particles was carried out according to the production process 10 of the carbonaceous material interior particles shown in 1.

The production test of the carbonaceous material interior particles was carried out according to the following procedure. First, iron ore powder having a particle size of 150 μm or less and a Braine specific surface area of 1500 cm ² / g, quicklime having a particle size of 75 μm or less, and polyvinyl alcohol powder having a particle size of 150 μm or less are mixed in a mass ratio of 95: 4: 1. The mixture was mixed in a ratio and uniformly mixed using an intensive mixer to obtain a mixed powder. This mixed powder and coke particles having a particle size of 2 mm or more and 8 mm or less were mixed at a mass ratio of 98: 2 to prepare a granulation raw material. This granulation raw material was rolled using a disc pelletizer to granulate the granulation raw material, and carbon material inner particles in which an outer layer made of a mixed powder was formed around the carbon material were produced. The water required for granulation of the granulation raw material was supplied by spraying an appropriate amount into the intensive mixer and the disc pelletizer.

FIG. 4 is a graph showing the relationship between the water content ratio of the carbonaceous material interior particles produced by the method for producing the carbonaceous material interior particles according to the present embodiment and the crushing strength. In FIG. 4, the horizontal axis is the water content ratio (mass%) of the carbonaceous material interior particles, and the vertical axis is the crushing strength (N / piece) of the carbonaceous material interior particles. Immediately after the carbonaceous material interior particles were granulated, the water content was 7 to 8% by mass, and at this point, the crushing strength of the carbonaceous material interior particles was 9.8 N / piece or more. From this result, even when iron ore powder having a Braine specific surface area of less than 1800 cm ² / g or a particle size of 45 μm or less and an iron ore powder having a content of less than 80% by mass is used, the mixed powder containing the iron ore powder is used. It was confirmed that the carbonaceous material interior particles having a crushing strength of 9.8 N / piece or more can be produced by blending the polyvinyl alcohol powder so that the blending ratio of the polyvinyl alcohol powder is 1% by mass or more. On the other hand, when the polyvinyl alcohol powder was not blended, the crushing strength of the carbonaceous material interior particles was 2.0 to 3.9 N / piece, and the crushing strength could not be 9.8 N / piece or more.

Further, as shown in FIG. 4, when the water content is reduced by drying, the crushing strength of the carbonaceous material interior particles is improved. In particular, by reducing the water content of the carbonaceous material interior particles to 2% by mass or less, the crushing strength of the carbonaceous material interior particles is greatly improved. Therefore, the water content of the carbonaceous material interior particles is dried to 2% by mass or less. It is preferable, and it is more preferable to dry the water content of the carbonaceous material interior particles to 1% by mass or less. As a result, the strength of the carbonaceous material interior particles can be improved without increasing the blending amount of the organic binder.

Next, the mass ratios of iron ore powder, quicklime, and polyvinyl alcohol powder were 95.9: 4.0: 0.1, 95.0: 4.0: 1.0, and 94.0: 4. The carbonaceous material interior particles were produced by changing the mixing ratio so as to be 0.0: 2.0 and 93.0: 4.0: 3.0, and the crushing strength of each carbon material internal particle was measured. The result is shown in FIG.

FIG. 5 is a graph showing the relationship between the mixing ratio of polyvinyl alcohol powder and the crushing strength of the carbonaceous material interior particles. In FIG. 5, the horizontal axis is the mixing ratio (mass%) of the polyvinyl alcohol powder to the mixed powder, and the vertical axis is the crushing strength (N / piece) of the carbonaceous material interior particles. As shown in FIG. 5, the crushing strength of the carbonaceous material interior particles can be improved by increasing the mixing ratio of the polyvinyl alcohol powder to the mixed powder. On the other hand, even if the compounding ratio of the polyvinyl alcohol powder was higher than 2% by mass, the crushing strength of the carbonaceous material interior particles did not improve, and a saturation tendency was observed. Further, when the polyvinyl alcohol powder is mixed so that the mixing ratio of the polyvinyl alcohol powder to the mixed powder is 3% by mass or more, the polyvinyl alcohol powder dissolves in the water brought in of the iron ore powder and the water supplied at the time of granulation, and the viscosity increases. As a result, stable granulation became difficult. From these results, it is preferable to mix the polyvinyl alcohol powder so that the mixing ratio of the polyvinyl alcohol powder to the mixed powder is 0.1% by mass or more and 3.0% by mass or less, and the mixing ratio of the polyvinyl alcohol powder to the mixed powder. It can be seen that it is more preferable to blend the polyvinyl alcohol powder so that the content is 0.1% by mass or more and 2.0% by mass or less.

As described above, by implementing the method for producing the carbonaceous material interior particles according to the present embodiment, the carbonaceous material interior particles having high crushing strength can be produced, so that the particles are transported to the sintering machine and mounted on the sintering machine. It is possible to reduce the amount of carbonaceous material interior particles that disintegrate in the process of being inserted. Then, by sintering the sintering raw material containing the sinter interior particles to produce the sinter for the sinter, a large amount of sinter structure that is easily reduced to the sinter is formed, and the sinter for the interior of the sinter. Improvement of ore reduction efficiency can be realized.

Further, even when iron ore powder having a specific surface area of less than 1800 cm ² / g or a particle size of 45 μm or less and an iron ore powder having a content of less than 80% by mass is used, the mixing ratio of polyvinyl alcohol powder to the mixed powder is still high. It was confirmed that by blending polyvinyl alcohol powder so as to be 1% by mass or more, it is possible to produce highly strong carbonaceous material interior particles that can be directly sent to the sintering machine.

Next, the result of confirming the reduction reactivity of the sinter for the interior of the carbonaceous material produced by sintering the sintering raw material containing the inner particles of the carbonaceous material will be described. FIG. 6 is a graph showing RI of sinters of Examples and Comparative Examples. RI is an index showing the reducibility of the sinter, and is a value measured in accordance with JIS M 8713.

In the comparative example shown in FIG. 6, it is simulated that the polyvinyl alcohol powder is not mixed and the carbonaceous material interior particles are disintegrated in the process of being transported to and charged into the sintering machine, and the sintering material does not contain the carbonaceous material internal particles. The raw material was charged into the sinter at a charging rate of 650 t / h to produce sinter. On the other hand, in the embodiment, assuming that the carbonaceous material interior particles do not disintegrate in the process of blending the polyvinyl alcohol powder and transporting and charging it to the sintering machine, the amount of the carbonaceous material interior particles is about 7% by mass (about 50 t / /). (Equivalent to h) The blended sintering raw material was charged into a sinter at a charging rate of 650 t / h to produce a sinter.

As shown in FIG. 6, it was confirmed that the RI of the carbonaceous interior sinter of the example was 3% higher than the RI of the sinter of the comparative example. From this result, by producing the carbonaceous material interior particles having high crushing strength by using the method for producing the carbonaceous material interior particles according to the present embodiment, the carbon material interior that collapses in the process of being transported to the sintering machine and charged. It can be seen that the number of particles can be reduced, and as a result, the reducibility of the sinter for the sinter which is produced from the sinter raw material containing the sinter for the sinter can be improved.

10 Manufacturing process of carbonaceous material interior particles 12 Iron ore powder 14 Storage tank 16 Fresh lime 18 Storage tank 20 Polyvinyl alcohol powder 22 Storage tank 24 Transporter 26 Water 28 Kneader 30 Mixing powder 32 Coke particles 34 Storage tank 36 Transporter 38 Granulator 40 Coal material interior particles 50 Raw material 52 Granulator 60 Downward suction type sintering machine 70 Blast furnace 100 Coal material interior sintered ore manufacturing process

Claims (3)

A powdery iron-containing raw material, a lime-containing raw material, and a polyvinyl alcohol powder are mixed to form a mixed powder.
A method for producing carbonaceous material interior particles, wherein the mixed powder and the carbonaceous material are granulated to produce carbonaceous material interior particles in which an outer layer made of the mixed powder is formed around the carbon material core .
The mixing ratio of polyvinyl alcohol powder to the mixed powder is 0.1% by mass or more and 3.0% by mass.
% Or less, a method for producing carbonaceous material interior particles, in which the polyvinyl alcohol powder is blended. The method for producing carbonaceous material interior particles according to claim 1 , wherein the polyvinyl alcohol powder is a polyvinyl alcohol powder sieved under a sieve with a 100-mesh sieve. The carbonaceous material interior particles produced by the method for producing carbonaceous material interior particles according to claim 1 or 2 , are converted into granulated particles obtained by mixing and granulating an iron-containing raw material, an auxiliary raw material, and a coagulant. Blend and use as a sintering raw material
A method for producing a carbonaceous interior sinter, in which the sintering raw material is charged into a pallet of a sintering machine and sintered.