WO2012015065A1

WO2012015065A1 - Method for producing starting material for sintering

Info

Publication number: WO2012015065A1
Application number: PCT/JP2011/067722
Authority: WO
Inventors: 隆英樋口; 大山　伸幸; 直幸竹内; 主代　晃一
Original assignee: Ｊｆｅスチール株式会社
Priority date: 2010-07-30
Filing date: 2011-07-27
Publication date: 2012-02-02
Also published as: JP5051317B1; CN103052724A; JP2013036049A; CN103052724B

Abstract

Provided is a method for producing a starting material for sintering, wherein it is possible to improve productivity compared to conventional methods by effectively using high-carbon dust during the process in which the surfaces of preliminary particles are being covered with a solid-fuel-based powder starting material. When the surfaces of the preliminary particles are being covered with a solid-fuel-based powder starting material, a solid-fuel-based powder starting material containing 5 to 40 mass% of high-carbon dust is used as the solid-fuel-based powder starting material.

Description

Method for manufacturing raw materials for sintering

The present invention relates to a method for producing a raw material for sintering used when producing a sintered ore using a downward suction type dweroid type sintering machine.

The sintered ore charged into the blast furnace is generally manufactured through the following treatment.
First, raw materials roughly divided into the following (a) to (d) are charged into a drum mixer, mixed with an appropriate amount of water, and granulated to produce a granular sintering raw material. To do.
(A) Iron ore (ore ore, return ore)
(B) SiO ₂ -containing raw material comprising silica, serpentine, nickel slag, etc. (c) Limestone-based powder raw material containing CaO such as limestone (d) Solid fuel-based powder raw material serving as a heat source for powder coke, anthracite, etc.

The sintering raw material composed of the granulated particles obtained by mixing and granulating the materials (a) to (d) described above has a predetermined thickness (usually 500 to 700 mm) on the pallet of a dwy-toroid type sintering machine. Are stacked in layers. Next, the solid fuel powder material distributed in the upper part of the sintering raw material layer loaded on the pallet is ignited, and after ignition, the solid fuel powder material is burned while sucking air downward. The raw material for sintering is sintered with combustion heat to form a sintered cake. At that time, hematite contained in iron ore reacts with limestone powder raw material and CaO contained in iron ore to produce calcium ferrite melt (hereinafter referred to as CF melt), which CF melt is used for sintering. Contributes to the combination of raw materials. This sintered cake is crushed and sized to become a sintered ore having a predetermined particle size. On the other hand, the sintered ore that does not satisfy the predetermined particle size is returned to ore and reused as a sintering raw material.

When sintering the raw material for sintering, there are the following two problems.
i) If the solid fuel powder raw material is effectively adhered to the surface of the sintering raw material, the combustibility of the solid fuel powder raw material can be improved.
ii) If the function of the CF melt can be improved by selectively generating the CF melt on the surface of the raw material for sintering, not only can the sintered ore be produced efficiently, but also blended into the raw material for sintering The amount of various materials used can be reduced.
In order to solve the above-mentioned problems, a technique for selectively generating a solid fuel-based powder raw material or a CF melt on the surface of a sintering raw material has been studied.

For example, regarding the former, Patent Document 1 describes that (a) iron ore, (b) SiO ₂ -containing material, and (c) limestone powder material are loaded from the inlet of the drum mixer, except for the solid fuel powder material. A technique for adding a solid fuel-based powder raw material at a position where the residence time until the granulated particles (hereinafter referred to as pseudo particles) reach the outlet is 10 to 120 seconds is disclosed. ing.
In the raw material for sintering obtained by this technique, the solid fuel-based powder raw material can be attached to the surface of the pseudo particles obtained by granulating the iron ore, the SiO ₂ -containing raw material, and the limestone-based powder raw material. As a result, the solid fuel-based powder raw material is not taken into the pseudo-particles and burns in the surface of the pseudo-particles, so that the flammability is greatly improved, and the solid fuel-based powder raw materials such as powder coke and anthracite Therefore, it is possible to increase the pseudo particle size by granulating except this.

Regarding the latter, in Patent Document 2, the above-mentioned (a) iron ore and (b) SiO ₂ -containing raw material are charged and granulated from the inlet of the drum mixer, and the pseudo particles after granulation are discharged. A technique is disclosed in which (c) a limestone powder raw material and (d) a solid fuel powder raw material are added to pseudo particles at a position where the residence time until reaching the outlet is 10 to 90 seconds. .
In the sintering raw material obtained by this technique, the limestone powder raw material and the solid fuel powder raw material are attached to the surface of the pseudo particles made of iron ore and the SiO ₂ -containing raw material. Therefore, when such a raw material for sintering is sintered, a CF melt is selectively generated on the surface of the raw material for sintering, and the formation of calcium silicate is suppressed.

However, even with such a technology, due to the recent demand for CO ₂ reduction, when the amount of powder coke, which is a solid fuel-based powder raw material, is reduced, the amount of powder coke coating is reduced and a sufficient effect is obtained. There was nothing.

In sintering the raw material for sintering, powdered coke, anthracite, or the like is used as a solid fuel-based powder raw material.
On the other hand, the coke cooling method at the time of coke production includes a wet type and a dry type (referred to as CDQ). Due to the characteristics of the apparatus, a considerable amount of fine coke is generated when any apparatus is used. The fine coke has been piled up for a long time.
However, it is desirable to use such fine coke from the viewpoint of effective use of resources.

For this reason, for example, Patent Document 3 proposes a technique of using finely ground coke generated in the coke production process as a fuel for producing sintered ore, which is an iron source charged in a blast furnace. That is, in order to produce a sintered ore, powdery coke as a heat source is mixed with powdered iron ore, limestone, etc., and agglomerated by the combustion heat of the coke.
The above-mentioned patent document 3 kneads fine powder raw materials such as converter dust, sintered dust and water in fine powder coke recovered by CDQ at an appropriate ratio, and is a fuel for manufacturing sintered ore (hereinafter referred to as a sintering fuel). ) As a preferred particle size. As a result, it was expected that fine coke in a dry state could be reused while suppressing generation of dust.

However, since the sintering fuel produced as described above has low strength as individual particles, it collapses when mixed with other sintering raw materials with a drum mixer, and the sintering raw materials are sintered. When a packed bed is formed on the machine pallet, fine coke is mixed and unevenly distributed in the packed bed. Therefore, when the so-called “sintering operation” is performed by igniting in this state, there is a problem that uneven burning occurs in the sintering machine and a preferable operation cannot be performed.

In addition, since the fine powder coke generated by CDQ is in a dry state, dust is generated during handling. On the other hand, fine powder coke generated in a wet fire extinguisher is in a wet state, so it is necessary to reuse it after adding a drying process. In both cases, the cost of handling and drying is high for reuse.
Therefore, regardless of the wet method or the dry method, fine coke generated in coke cooling is sprayed on piles of iron ore that constitute the raw material for sintering, as described in Patent Document 4 and Patent Document 5. It has been practiced to disperse uniformly in the sintering raw material and use the sintering machine so that uneven burning does not occur.

In addition, in Patent Document 6, (a) iron ore and (b) SiO ₂ -containing raw material are charged from a charging port of a drum mixer and granulated. Disclosed is a technology that, when adding a limestone powder raw material and (d) a solid fuel powder raw material, the amount of coke powder mixed in (a) iron ore and (b) SiO ₂ containing raw material is kept to 1.5 mass% or less. Has been.
In this way, conventionally, finely ground coke is stopped using or the amount of mixing is stopped to 1.5 mass% or less, and the remaining portion is reused by being mixed into raw coal as waste. It was.

Japanese Patent No. 3794332 Japanese Patent No. 3755452 JP 61-291926 A JP 2000-169915 A JP 2000-96154 A Japanese Patent No. 39951825

The present invention is a further improvement of the technologies disclosed in

Patent Documents

1 and 2 listed above. Conventionally, fine coke that has been regarded as waste because of uneven burning in a sintering machine, It can be reused as a solid fuel powder material (condensation material) during production.

That is, the present invention is a treatment for attaching a solid fuel-based powder raw material (hereinafter referred to as an exterior treatment) to the surface of the pseudo particle that is a granulated product composed of iron ore, a SiO ₂ -containing raw material, and a limestone powder raw material, In the exterior treatment of attaching limestone powder raw material and solid fuel powder raw material to the surface of pseudo particles of iron ore and SiO ₂ -containing raw material, it is contrary to the conventional knowledge by effectively utilizing fine powder coke etc. Furthermore, it aims at providing the advantageous manufacturing method of the raw material for sintering which can improve productivity.

Now, the present inventors have intensively studied a technology for improving productivity when performing so-called exterior treatment in which a solid fuel powder raw material, or a limestone powder raw material and a solid fuel powder raw material are attached to the surface of a pseudo particle. went.
As a result, high carbon dust such as fine coke generated in CDQ, etc., is used in combination with solid fuel-based powder raw materials represented by conventional powder coke and anthracite at an appropriate ratio so as to adhere to pseudo particles. In this way, it was newly found that not only productivity is improved but also combustibility and granulation strength are greatly improved.
In addition, according to the present invention, in addition to the fine powder coke generated in the above-described CDQ and the like, it was investigated that fine powder having a C concentration of 50 mass% or more can be used, and these are collectively referred to as high carbon dust. .
The present invention has been made based on these findings.

That is, the gist configuration of the present invention is as follows.
(1) Prepare a sintering raw material consisting of iron ore, SiO ₂ containing raw material, limestone powder raw material and solid fuel powder raw material,
From the drum mixer inlet, iron ore, SiO ₂ containing raw material and limestone powder raw material are charged and granulated to form pseudo particles,
A solid fuel-based powder raw material is added to the pseudo particles, and the solid fuel-based powder raw material is attached to the surface of the pseudo particles while being discharged from the drum mixer,
The solid fuel-based powder raw material contains 5 to 40 mass% of high carbon dust.
A method for producing a raw material for sintering.

(2) preparing a sintering raw material comprising iron ore, SiO ₂ -containing raw material, limestone powder raw material and solid fuel powder raw material,
The iron ore and the SiO ₂ -containing raw material are charged from the drum mixer inlet and granulated to form pseudo particles,
A solid fuel powder raw material and a limestone powder raw material are added to the pseudo particles, and the solid fuel powder raw material and the limestone powder raw material are put on the surface of the pseudo particles while reaching the discharge port of the drum mixer. Attach
The solid fuel-based powder raw material contains 5 to 40 mass% of high carbon dust.
A method for producing a raw material for sintering.

(3) The method for producing a sintering raw material according to (1) or (2), wherein the solid fuel-based powder raw material contains 10 to 40 mass% of high carbon dust.
(4) The method for manufacturing a raw material for sintering according to (1) or (2), wherein the high carbon dust has a size of 50 μm or less and a C concentration of 50 mass% or more.

(5) The method for producing a sintering raw material according to (1) or (2), wherein the pseudo particles do not contain high carbon dust.

(6) The method for producing a raw material for sintering according to (1), wherein the solid fuel-based powder raw material is added such that a residence time from the addition to discharge from the drum mixer is 10 to 50 seconds. .
(7) The method for producing a sintering raw material according to (6), wherein the residence time is 20 to 40 seconds.
(8) The sintering according to (2), wherein the solid fuel-based powder raw material and the limestone-based powder raw material are added so that a residence time from the addition to the discharge from the drum mixer is 10 to 50 seconds. For manufacturing raw materials.
(9) The method for producing a raw material for sintering according to (8), wherein the residence time is 20 to 40 seconds.

(10) The high carbon dust is at least one selected from the group consisting of CDQ dust collection powder, dust collection powder during iron powder production, and dust collection powder in a storage tank, and the C concentration is 50 mass% or more. The method for producing a raw material for sintering according to (1) or (2), which is adjusted.
(11) The method for producing a sintering raw material according to (1), wherein the solid fuel-based powder raw material has an average particle diameter of 250 μm to 2.5 mm.
(12) The firing according to (2), wherein the solid fuel-based powder raw material has an average particle diameter of 250 μm to 2.5 mm, and the limestone powder raw material has an average particle diameter of 250 μm to 5.0 mm. A method for producing a ligation raw material.

According to the present invention, since the high carbon dust is packaged on the surface of the pseudo particle, the pseudo particle diameter can be kept large, and since it is not embedded in the pseudo particle, the combustibility is improved. Furthermore, since it is used in combination with ordinary solid fuel, scattering of high carbon dust, which is fine powder, is suppressed and handling becomes easy. In addition, since the exterior is filled with high carbon dust in the solid fuel voids during the exterior, the strength of the exterior also increases, and as a result, the strength of the pseudo particles is improved, and when the sintering machine is supplied Powder generation is also reduced.
In addition, according to the present invention, since the pseudo particle diameter can be increased, the exterior time on the surface of the pseudo particle can be shortened, and the state of being built can be avoided.
Furthermore, since the solid fuel powder material using high carbon dust and the limestone powder material can be attached to the surface of the pseudo particles, the generation of CF is promoted and the generation of calcium silicate having a low strength is suppressed.
In addition, as a fuel, if the C concentration is 50 mass% or more, it can be used as a coagulating material for sintering. Even if the C concentration is less than 50 mass%, other fine powder having a C concentration of 50 mass% or more can be used. If it is mixed and the C concentration is adjusted to 50 mass% or more, it can be used.

It is a schematic diagram which shows the example of the manufacturing apparatus of a suitable raw material for sintering used when applying this invention, and manufacturing the raw material for sintering. It is a schematic diagram which shows another example of the manufacturing apparatus of a suitable raw material for sintering used when manufacturing a raw material for sintering by applying this invention. It is a figure which shows the relationship between the particle size of a powder coke, and a combustion rate. It is a figure which shows the relationship between the compounding rate of the high carbon dust in the pseudo | simulation particle | grains according to this invention which coat | covered the powder coke which used high carbon dust together, a combustion rate, and the highest ultimate temperature in a layer. Comparison of the granulated strength after granulation and the sintered strength after sintering between the pseudo particles according to the present invention in which powder coke combined with high carbon dust is used and the conventional pseudo particles with high carbon dust inside FIG. It is a figure which compares and shows the burning speed of the pseudo | simulation particle | grains according to this invention which coat | covered the powder coke and powder limestone which used high carbon dust together, and the conventional pseudo particle | grains which comprised high carbon dust. It is a figure which compares and compares the suitable exterior granulation time and sintering productivity of the pseudo | simulation particle | grains according to this invention which coat | covered the powder coke and powder limestone which used high carbon dust together, and the conventional pseudo particle | grains which comprised high carbon dust. FIG. 8A is an image view of a cross section of a pseudo particle in which high carbon dust is embedded according to a conventional method, and FIG. 8B is an enlarged view of the surface layer portion. FIG. 9A is an image view of a cross-section of a pseudo particle covering powdered coke and powdered limestone combined with high carbon dust according to the present invention, and FIG. 9B is an enlarged view of the surface layer portion.

The present invention will be specifically described below.
1 and 2 schematically show an example of a sintering raw material manufacturing apparatus suitable for use in manufacturing a sintering raw material by applying the present invention.
1 and 2, reference numeral 1 is a drum mixer, 2 is iron ore, 3 is a SiO ₂ -containing raw material, 4 is a limestone powder raw material, 5 is a solid fuel powder raw material, and 6 is a sintering raw material.

FIG. 1 shows that iron ore 2, SiO ₂ -containing raw material 3 and limestone powder raw material 4 are charged into the drum mixer 1 from the inlet and the solid fuel powder raw material 5 is discharged to the drum mixer outlet. It is a case where it adds.
FIG. 2 shows that the iron ore 2 and the SiO ₂ -containing raw material 3 are charged into the drum mixer 1 from the charging port, and the limestone powder raw material 4 and the solid fuel-based powder raw material 5 are reached to the discharge port of the drum mixer. It is a case where it adds.

Hereinafter, the manufacturing process of the raw material for sintering shown in FIGS. 1 and 2 will be described more specifically.
In the case of FIG. 1, the iron ore 2, the SiO ₂ -containing raw material 3 and the limestone-based powder raw material 4 are charged into the drum mixer 1 from the inlet and granulated. The pseudo particles made of the iron ore 2 and the SiO ₂ -containing raw material 3 granulated in the drum mixer 1 move to the discharge port.
Then, the solid fuel-based powder raw material 5 is added at a position set in the middle of the downstream side where the residence time (that is, the exterior time) until the pseudo particles reach the discharge port is in the range of 10 to 50 seconds.
As a specific method, for example, the position of the front end of a belt conveyor or a screw conveyor arranged so as to be able to advance and retreat in the longitudinal direction in the drum mixer 1 from the downstream discharge port is adjusted and the solid fuel powder raw material 5 is added. Thus, the exterior time can be maintained within a predetermined range. An appropriate amount of water may be added as necessary. As a result, the solid fuel powder raw material 5 is uniformly coated on the surface of the pseudo particles until the pseudo particles reach the discharge port.

In the case of FIG. 2, the iron ore 2 and the SiO ₂ -containing raw material 3 are charged into the drum mixer 1 from the charging port and granulated. The pseudo particles made of the iron ore 2 and the SiO ₂ -containing raw material 3 granulated in the drum mixer 1 move to the discharge port.
As in the case of FIG. 1, the limestone powder raw material 4 and the limestone-based powder raw material 4 are located at the downstream side where the residence time (that is, the exterior time) until the pseudo particles reach the outlet is in the range of 10 to 50 seconds. Solid fuel system powder raw material 5 is added. As a result, the limestone powder raw material 4 and the solid fuel powder raw material 5 are uniformly coated on the surface of the pseudo particles until the pseudo particles reach the discharge port.

By the way, conventionally, the average particle diameter of the solid fuel-based powder raw material 5 used for the exterior treatment is about 250 μm to 2.0 mm. In this way, the average particle size of the solid fuel-based powder raw material that has been conventionally used is relatively large, and it is not always possible to form a strong outer shell layer of the solid fuel-based powder raw material. The speed was not sufficiently satisfactory.

Therefore, the inventors have conducted various studies to solve this problem, and as a result, if high carbon dust that has been forgotten to be used in the past is too fine, combined use at an appropriate ratio, combustibility and granulation strength. As a result, it has been found that productivity is greatly improved.

FIG. 3 shows the results of examining the relationship between the particle size of the powder coke and the combustion zone moving speed (hereinafter simply referred to as the combustion speed).
As shown in the figure, the smaller the particle size of the powder coke, the greater the specific surface area of the powder coke and the higher the ambient temperature, so the combustion rate increases.
Therefore, an improvement in the combustion rate can be expected by using such ultrafine powder and highly reactive carbon material (high carbon dust) in an appropriate ratio.

Next, in FIG. 4, according to the present invention, the results of examining the influence on the burning rate and the maximum temperature reached in the layer of the pseudo particles coated with the powdered coke combined with the high carbon dust are shown. Shown in relation to rate. As the high carbon dust, fine powder having a sieve size of 50 μm was used. Further, the total coke amount in the pseudo particles was fixed at 5 mass%.
As shown in the figure, in the pseudo particles according to the present invention with high carbon dust sheathed, the mixing ratio of high carbon dust is 0.25 mass% or more, that is, the mixing ratio of high carbon dust out of all carbon (solid fuel powder raw material). When the ratio is 5 mass% or more, the combustion rate increases, and the maximum reachable temperature in the layer increases accordingly. However, when the blending ratio of the high carbon dust exceeds 2 mass% (combination ratio with respect to the powder coke: 40 mass%), the highest temperature reached in the layer starts to decrease.

Therefore, in the present invention, the blending ratio (combination ratio) of the high carbon dust in the solid fuel powder raw material is limited to a range of 5 to 40 mass%. This is because, in the solid fuel-based powder raw material, if the blending ratio of the high carbon dust is less than 5 mass%, it cannot be said that the improvement of the combustibility and the granulation strength is sufficient. This is because the flammability decreases and the combustibility deteriorates.

Next, according to the present invention, FIG. 5 shows the results of examining the granulated strength of the pseudo particles when the powder coke combined with the high carbon dust is used and the sintering strength when the sintering is performed thereafter. .
For comparison, FIG. 5 also shows the results of examining the granulation strength and the sintering strength of the pseudo particles when high carbon dust is housed inside the pseudo particles.
The granulation strength and sintering strength were estimated based on the following estimation formulas (Equation 1 and Equation 2).

Where σ: strength of pseudo particles (N), ψ: degree of liquid fullness (−), S: powder surface area (m ² ), ε: porosity of pseudo particles (−), γ: surface of water Tension (N / m), θ: contact angle with water (°), d: pseudo particle size (m)

Here, σ _t : tensile strength (MPa), σ ₀ : substrate strength (MPa), P: porosity (−), c: constant (−)

As shown in the figure, when the high carbon dust was packaged according to the present invention, the granulation strength of the pseudo particles was remarkably improved. The reason for this is considered to be that wettability is greatly improved by covering the hydrophobic carbonaceous material.
In addition, when the present invention is followed, the sintering strength of the pseudo particles is also greatly improved. This reason is considered to be caused by a decrease in the porosity. That is, according to the present invention, when an appropriate amount of high carbon dust is used in combination, fine high carbon dust penetrates into the voids of ordinary powder coke, and as a result, generation of voids (destructive origin) generated after carbon firing is suppressed. This is thought to be due to this.

Therefore, next, in FIG. 6, according to the present invention, the results of examining the burning rate of the pseudo particles coated with the powdered coke and powdered limestone combined with the high carbon dust and the pseudo particles equipped with the high carbon dust according to the conventional method are shown. It shows by the relationship with the compounding rate of the high carbon dust (ultra-fine carbonaceous material) in pseudo particles. The total amount of carbon (solid fuel powder raw material) in the pseudo particles was constant at 5 mass%.
As shown in the figure, in the conventional quasi-particles with high carbon dust, the combustion rate rather decreased as the blending ratio of high carbon dust increased.
On the other hand, in the case of the pseudo particles according to the present invention in which the high carbon dust is packaged, the combustion rate is greatly increased as the blending ratio of the high carbon dust is increased.

According to the results of FIG. 6, the blending ratio of high carbon dust in the pseudo particles (total carbon amount: 5 mass%) is 0.25 mass% or more, that is, the blending ratio of high carbon dust in the total carbon (solid fuel powder raw material). When it becomes 5 mass% or more, the improvement of a combustion rate is remarkable. However, when the blending ratio of high carbon dust out of the total carbon (solid fuel powder raw material) exceeds 40 mass%, the width of the combustion melting zone is expanded, resulting in an adverse effect of increasing the pressure loss in the sintered layer.
Therefore, in the present invention, the blending ratio (combination ratio) of high carbon dust in the solid fuel powder material is limited to a range of 5 to 40 mass%.

In the present invention, the high carbon dust preferably has a size of 50 μm or less and a C concentration of 50 mass% or more. This is because when the size of the high carbon dust exceeds 50 μm, the powder coke that is externally packed does not close-pack and the coverage on the particle surface tends to decrease. In addition, the suitable minimum of the magnitude | size of high carbon dust is 10 micrometers.
On the other hand, if the high carbon dust C concentration is less than 50 mass%, there is a disadvantage that the combustion heat is small and the coexistence of slag components and ash content inhibits the combustibility of the powder coke.
Here, the size of the high carbon dust is defined as a circle-equivalent diameter when the high carbon dust is spherical, and as a sieve diameter when the high carbon dust is non-spherical.
The high carbon dust is at least one selected from the group consisting of CDQ dust collection powder, dust collection powder during iron powder production, and dust collection powder in a storage tank, and the C concentration is adjusted to 50 mass% or more. It is preferable that Table 1 shows examples of components of CDQ dust collection powder, dust collection powder during iron powder production, and dust collection powder in the storage tank.

Next, FIG. 7 shows the results of examining the suitable external granulation time of the agenda in which high carbon dust according to the present invention is used together with the pseudo coke and powder limestone externally coated with the high carbon dust according to the conventional method, Shown in relation to sintering productivity.
As shown in the figure, the preferred exterior granulation time of the conventional pseudo particles was around 60 seconds, whereas the preferred exterior granulation time of the pseudo particles according to the present invention was about 20 to 40 seconds. The time was reduced to about 1/2.
Thus, the productivity of the drum mixer can be improved by reducing the exterior time in the exterior processing. Moreover, when the obtained raw material for sintering is sintered, a CF melt can be selectively generated on the surface of the raw material for sintering, and a sintered ore can be produced efficiently.

FIG. 8 (a) and FIG. 9 (a) show pseudo particles in which ultra fine powder and highly reactive carbonaceous material (high carbon dust) are provided according to the conventional method, and ultra fine powder and highly reactive carbonaceous material (high carbon dust) according to the present invention. ) In combination with powder coke and powdered limestone, the cross-sectional images of pseudo particles are shown in comparison. 8B and 9B are enlarged views of the surface layer portion of each cross section.
As is clear from a comparison between FIG. 8B and FIG. 9B, in the pseudo particles according to the conventional method, high carbon dust is scattered inside, whereas in the pseudo particles according to the present invention, the high particle is high. Carbon dust exists in the form of entering the gaps of the powder coke in the outer layer of the particles. As a result, the granulation strength and sintering strength as described above can be improved, the combustion rate can be increased, and the outer granulation time can be shortened. As a result, a marked improvement in productivity can be achieved.

1 and 2, in order to transport the limestone powder raw material 4 and the solid fuel powder raw material 5 to a position where a predetermined exterior time is secured, a transport device (for example, a belt conveyor, a screw conveyor) Etc.) must be inserted into the drum mixer 1. However, since a large amount of dust is floating in the drum mixer 1, the use of a belt conveyor increases the frequency of failure of a motor or a roller that supplies driving force to the belt.
Therefore, it is possible to feed the limestone powder raw material 4 and the solid fuel powder raw material 5 from the outside of the discharge port without inserting a belt conveyor into the drum mixer 1 and increasing the conveying speed. When this method is employed, when the limestone powder raw material 4 and the solid fuel powder raw material 5 are added to the pseudo particles, not only the impact of natural fall but also the horizontal impact is applied due to the conveying speed. Accordingly, the pseudo particles are likely to collapse, and the limestone powder raw material 4 and the solid fuel powder raw material 5 are mixed inside the pseudo particles.

The screw conveyor does not need to be equipped with a large number of rollers and has a simple structure. Therefore, even if it is inserted into the drum mixer 1, it can hardly be broken and can be operated stably. If the screw conveyor is inserted into the drum mixer 1, the tip position can be adjusted and the limestone powder raw material 4 and the solid fuel powder raw material 5 can be added to predetermined positions. In that case, since the impact is relaxed (only the impact of natural fall), the collapse of the pseudo particles can be prevented. Further, the collapse of the limestone powder raw material 4 and the solid fuel powder raw material 5 can be prevented, and the particle diameter adjusted in advance can be maintained. Accordingly, it is preferable to use a screw conveyor as the conveying means.

The average particle diameter of the limestone powder raw material 4 used for the exterior treatment is preferably 250 μm to 5.0 mm, and the average particle diameter of the solid fuel powder raw material 5 is preferably 250 μm to 2.5 mm. When the average particle diameter of the limestone powder raw material 4 exceeds 5.0 mm and the average particle diameter of the solid fuel powder raw material 5 exceeds 2.5 mm, the coarse particles of the limestone powder raw material 4 and the solid fuel powder raw material 5 Therefore, it becomes difficult to uniformly coat the surface of the pseudo particle in a short time. On the other hand, if the average particle size is less than 250 μm, the fine particles of the limestone powder raw material 4 and the solid fuel powder raw material 5 increase and intrude through gaps that inevitably exist in the pseudo particles, and also enter the limestone powder. The raw material 4 and the solid fuel-based powder raw material 5 are mixed into the sintering raw material. When such a sintering material is sintered, the effect of selectively generating the CF melt on the surface of the sintering material cannot be obtained.
The blending ratios of the solid fuel powder raw material and the limestone powder raw material with respect to the entire sintering raw material are respectively 3.0 to 6.0 mass% for the solid fuel powder raw material and 6.0 to 12% for the limestone powder raw material. It is preferable to set it to about 0 mass%. More preferably, they are in the range of solid fuel powder raw material: 3.5 to 5.0 mass%, limestone powder raw material: 6.5 to 10.0 mass%.

Furthermore, if the exterior time is less than 10 seconds, the surface of the pseudo particles cannot be uniformly coated. If the exterior time exceeds 50 seconds, the limestone powder raw material 4, the solid fuel powder raw material 4, since the pseudo particles collapse and granulate again after adding the limestone powder raw material 4 and the solid fuel powder raw material 5. 5 is mixed inside the pseudo particle. As a result, not only the surface of the pseudo particles cannot be uniformly coated, but also the sintering raw material in which the limestone powder raw material 4 and the solid fuel powder raw material 5 are mixed. Therefore, the exterior time is preferably about 10 to 50 seconds. More preferably, it is in the range of 20 to 40 seconds.

Example 1
As shown in FIG. 2, the iron ore 2 and the SiO ₂ -containing raw material 3 were charged into the drum mixer 1 from the charging port and granulated. In addition, as the SiO ₂ -containing raw material 3, silica stone or nickel slag was used. In the drum mixer 1, the iron ore 2 and the SiO ₂ -containing raw material 3 are granulated into pseudo particles, and the limestone is at a position where the residence time until the pseudo particles reach the discharge port of the drum mixer 1 is 40 seconds. Limestone with an average particle diameter of 0.9 mm: 10 mass% as the system powder raw material 4 and high coke dust with an average particle diameter of 0.9 mm as the solid fuel system powder raw material 5: 4 mass% and an average particle diameter of 50 μm: 1 mass% (combination ratio to all coke: 20%) was added. Moreover, the specific addition method adjusts the front-end | tip position of the screw conveyor arrange | positioned so that it can advance / retreat to the longitudinal direction in the drum mixer 1 from a discharge port, and the residence time until a pseudo particle reaches a discharge port is 40 seconds. The limestone powder raw material 4 and the solid fuel powder raw material 5 were added to the position. Therefore, the exterior time is 40 seconds.
This is an invention example.

On the other hand, as Comparative Example 1, the iron ore 2 and the SiO ₂ -containing raw material 3 are charged into the drum mixer 1 from the charging port and granulated, and the pseudo particles reach the discharge port of the drum mixer 1 as in the invention example. In the position where the residence time of the limestone becomes 80 seconds, the limestone powder raw material 4 has a particle size of 1.9 mm: limestone: 10 mass% and the solid fuel powder raw material 5 has a particle size of 1.9 mm of powder coke: 5 mass% did. Therefore, the exterior time is 80 seconds.

Further, as Comparative Example 2, a raw material for sintering was manufactured under the same conditions as Comparative Example 1 except that the exterior time was 40 seconds.

Sintering raw materials for the inventive examples and comparative examples 1 and 2 were sintered. As a result, a sintered ore having sufficient strength was obtained with the sintering raw materials of the inventive example and comparative example 1. This indicates that the CF melt was generated on the surface of the raw material for sintering.

However, the sinter produced from the raw material for sintering of Comparative Example 2 was inferior in strength to the sintered ore using the raw material for sintering of Comparative Example 1. This indicates that the limestone powder raw material 4 and the solid fuel powder raw material 5 could not be uniformly coated on the surface of the pseudo particles, so that the generation of CF melt was uneven.

That is, according to the present invention, when the raw material for sintering is manufactured, the exterior time can be shortened, and further, the sintered raw material having sufficient strength can be obtained by sintering the raw material for sintering.

1 a drum mixer 2 ore 3 SiO ₂ containing feedstock 4 limestone based flour raw material 5 solid fuel based flour material 6 sintering raw material

Claims

Prepare a sintering raw material consisting of iron ore, SiO 2 containing raw material, limestone powder raw material and solid fuel powder raw material,
From the drum mixer inlet, iron ore, SiO 2 containing raw material and limestone powder raw material are charged and granulated to form pseudo particles,
A solid fuel-based powder raw material is added to the pseudo particles, and the solid fuel-based powder raw material is attached to the surface of the pseudo particles while being discharged from the drum mixer,
The solid fuel-based powder raw material contains 5 to 40 mass% of high carbon dust.
A method for producing a raw material for sintering.
Prepare a sintering raw material consisting of iron ore, SiO 2 containing raw material, limestone powder raw material and solid fuel powder raw material,
The iron ore and the SiO 2 -containing raw material are charged from the drum mixer inlet and granulated to form pseudo particles,
A solid fuel powder raw material and a limestone powder raw material are added to the pseudo particles, and the solid fuel powder raw material and the limestone powder raw material are put on the surface of the pseudo particles while reaching the discharge port of the drum mixer. Attach
The solid fuel-based powder raw material contains 5 to 40 mass% of high carbon dust.
A method for producing a raw material for sintering.
The method for producing a sintering raw material according to claim 1 or 2, wherein the solid fuel-based powder raw material contains 10 to 40 mass% of high carbon dust.
The method for producing a raw material for sintering according to claim 1 or 2, wherein the high carbon dust has a size of 50 µm or less and a C concentration of 50 mass% or more.
The method for producing a raw material for sintering according to claim 1 or 2, wherein the pseudo particles do not contain high carbon dust.
2. The method for producing a sintering raw material according to claim 1, wherein the solid fuel-based powder raw material is added such that a residence time from the addition to discharge from the drum mixer is 10 to 50 seconds.
The method for producing a raw material for sintering according to claim 6, wherein the residence time is 20 to 40 seconds.
The sintering raw material according to claim 2, wherein the addition of the solid fuel powder raw material and the limestone powder raw material is performed such that a residence time from the addition to the discharge from the drum mixer is 10 to 50 seconds. Production method.
The method for producing a raw material for sintering according to claim 8, wherein the residence time is 20 to 40 seconds.
The high carbon dust is at least one selected from the group consisting of CDQ dust collection powder, dust collection powder during iron powder production, and dust collection powder in a storage tank, and the C concentration is adjusted to 50 mass% or more. The method for producing a raw material for sintering according to claim 1 or 2, wherein
The method for producing a raw material for sintering according to claim 1, wherein the solid fuel-based powder raw material has an average particle diameter of 250 µm to 2.5 mm.
The solid fuel-based powder raw material has an average particle diameter of 250 μm to 2.5 mm;
The limestone powder raw material has an average particle diameter of 250 μm to 5.0 mm,
The manufacturing method of the raw material for sintering of Claim 2.