JP2001164325A - Method for manufacturing sintered ore for blast furnace and operational method for manufacturing sintered ore for blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the strength and the yield of sintered ore by receiving lime stone of the grain size distribution as by the ordinary way from a mine, utilizing fine grains without exhausting them out of the system and using a large amount of highly crystallized water-containing ore. SOLUTION: The lime stone 2 is screened and the minus-mesh fine grain lime stones 17 are granulated into pseudo-grains 19 and blended with powdery iron ore 1, or the like, and plus-mesh lime stone 20 to prepare pseudo-grains for sintering, and the sintered ore is produced. The above sintered ore producing process and a sintered ore producing process using the pseudo-grains for sintering by using the lime stone 2 without screening are operated by changing over at any time. The separation point of the screening is made to 1, 0.5 or 0.25 mm. The pseudo-grains for sintering are charged into a pallet in a sintering machine with a charging device having a grain size segregation forming function in the thickness direction of raw material layer. The distribution of the CaO concentration in the raw material charged into the pallet in the raw material thickness direction is formed so as to be higher from the upper layer part toward the lower layer part. Further, the operation after blending a large amount of the high crystallized water-containing ore is execute.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for using limestone, which is important as one of the auxiliary materials of sinter for blast furnaces,
The present invention relates to a technique for producing sinter which uses limestone more efficiently while maintaining the quality of sinter, and further uses a large amount of highly crystalline water ore.

[0002]

2. Description of the Related Art Sinters used as raw materials for blast furnaces are:
Generally, it is manufactured as follows. First, iron ores unloaded from the Vessel are piled up in the ore yard for each brand.
Then piled various powder ore and containing CaO auxiliary material, containing SiO ₂ auxiliary materials, dust including iron, and the carbonaceous material or the like is mixed with a predetermined ratio bedding method blending powder. Raw materials such as the blending powder, plain iron ore, limestone, silica stone, coke breeze and returned ore are cut out from the respective mixing tanks, and water is added to the mixed raw materials to mix and granulate. The sintering material in the form of quasi-particles thus granulated is charged into a pallet of a sintering machine, and the carbon material is ignited by an ignition furnace. Sinter and agglomerate. After cooling the fired sintered cake, it is crushed and sized, and a product having a size of 3 to 50 mm is used as a product sinter ore as a raw material for a blast furnace.

[0003] Limestone used in the above-mentioned sinter production process is used as a slag-making material in an amount of 10 wt. % Or more. The initial melt formation reaction during raw material sintering mainly starts at the contact point between limestone and fine ore, and limestone exhibits a binder function during sintering. This melt formation reaction has a significant effect on the quality of the sinter ore and the stability of the sintering operation. Further, since the amount of limestone is so large, the particle size has a considerable influence on the particle size distribution of the entire raw material charged into the sintering machine. For example, when the particle size distribution of limestone is large, the permeability of the sintering material layer on the sintering machine bed is good, and the production rate per unit time increases.

[0004] Therefore, the particle size of limestone in the sintering raw material is a very important factor in the sinter production process. Conventionally, regarding the particle size of limestone, conventionally, generally 3 mm
By using the following, the amount of melt generated during sintering is increased to secure the strength of the sinter, and the yield of products resulting from securing the strength of the sinter is improved (based on the strength management standards). Pass rate). However, if the limestone particle size control standard is set to 3 mm or less, the productivity of the sinter ore and the tendency to reduce pulverization deteriorate. The main reason why productivity decreases when the limestone particle size is small is, for example, 1 mm
In the case of limestone having a degree of less than or equal to 1,100 ° C. or more during the heating process, the limestone is easily decomposed into CaO and CO ₂ , and quickly reacts with iron oxide in the fine ore to form a melt. Therefore, the air permeability of the sintered layer is deteriorated from the relatively early stage of sintering, the amount of suction air is reduced, and the production rate is reduced. In this way, while maintaining the strength and yield of the sinter at a certain level,
This is a method for producing sinter which has poor sinter productivity and reduced powdering properties.

Therefore, the management standard of limestone particle size was reviewed,
Various proposals have been made with the aim of ensuring the strength of the sintered ore and improving the product yield, and at the same time improving the reduction pulverizability and improving the productivity by blending an appropriate amount of limestone of 3 mm or more.

For example, Japanese Patent Application Laid-Open No. 57-54230 discloses that limestone is crushed and classified (0.5 to 1) mm or more for the purpose of improving the reduction pulverizability of sinter. The weight ratio should be approximately 1/2, and those with (0.5-1) mm or more are more in the lower part of the sintering material layer, and those with less than (0.5-1) mm are sintered. It is increased in the upper part of the machine raw material layer, and an appropriate value of the ratio is disclosed (hereinafter referred to as “prior art 1”).

The particle size of limestone is divided into fine particles, fine particles and coarse particles, and the upper limit of the ratio is set lower for fine particles and coarse particles. In addition, there is a proposal to produce a sintered ore with good reduction powdering property while securing strength and yield at a certain level by setting the lower limit of the mixing ratio to a higher value. For example, JP-A-57-1
No. 92228 discloses that the particle size of limestone is 1 to 1 in the intermediate region.
3 mm 50 wt. % Or more in a coarse-grained region of 3 to 5 mm. % Or less and 0.25 mm or less in a fine grain region of 19 wt. %, And a method of blending with other raw materials is described (hereinafter referred to as “prior art 2”).

Further, Japanese Patent Application Laid-Open No. 7-252541 discloses a limestone in a sintering operation for charging a grain size segregation strengthening type raw material in which the particle size distribution in the thickness direction of the sintering raw material is coarse in the lower layer and fine in the upper layer. The purpose of the present invention is to produce a sintered ore with good reducibility and pulverizability with good productivity while avoiding a decrease in sintering yield due to insufficient slagging due to an excessively large particle size of iron, that is, an insufficient reaction between iron ore and limestone. And Then, on the premise that a charging device having a function of strengthening the particle size segregation in the thickness direction of the raw material layer of the sintering machine is used, the ratio of limestone having a particle size of 3 to 5 mm is made larger than the conventional level, and 10-30
wt. % (Hereinafter referred to as “prior art 3”).

On the other hand, in terms of iron ore supply, hematite (Fe ₂ O ₃ , hematite) and magnetite (Fe ₃ O ₄ ,
High-quality iron ore such as magnetite) is reduced, and a high crystal water content such as a pisolite ore or maramamba ore containing a large amount of goethite (Fe ₂ O ₃ .nH ₂ O) is generated. Ore ”is increasing. The content of water of crystallization in ore reaches as high as about 10% by mass. There has been a strong demand for a technique for using such a highly crystalline water ore in a large amount and advantageously as a sinter for a blast furnace.

However, the above-mentioned highly crystalline water ore generally has the following problems when used as a raw material for producing sinter. 1. Heat compensation is required for the thermal decomposition reaction at the time of elimination of water of crystallization that occurs when the temperature of the sintering raw material rises, and accordingly, more coke breeze is required. 2. Due to the porosity resulting from the elimination of water of crystallization, a local overmelting reaction is caused by the melt generated during the melting reaction of the sintering raw material. Due to the high melting property of such a high crystal water ore, air permeability in a sintering raw material layer in a pallet of a sintering machine is hindered. For this reason, the sintering productivity and yield are reduced. 3. Highly crystalline water ore has a low degree of crystallinity and is easily pulverized, so that the proportion of fine or fine powder is large. For this reason, the granulation of the sintering raw material is inferior and the permeability of the sintering raw material layer in the sintering machine bed is inferior, and as a result, the sintering production rate and yield are reduced.

Conventionally, the ratio of highly crystalline water ore containing (4 to 5) mass% or more of crystallization water to the mixed raw material is 2%.
If it is increased to about 5 mass% or more, the first to third
It has been found that the problem of the term becomes significant.

In order to solve such a problem when using highly crystalline water ore, the prior art proposes removing crystal water in advance, or controlling the composition of the initial melt in the sintering process to overmelt. Proposals have been made to curb this.

[0013]

The above prior arts are all excellent in that they achieve their intended direct goals. However, in each case, the following problems remain.

First, a conventional technique based on limestone particle size control will be discussed. According to Prior Art 1, the size of limestone having a particle size (0.5 to 1) mm or less must be reduced to about 、 or less. However, limestone is usually transported from a yamamoto to a sinter production process. The ratio of limestone of (0.5 to 1) mm or less is significantly higher than this. Therefore, it is necessary to develop a method of utilizing the remainder of the limestone having the particle size by any method. Also, in Prior Art 2, the proportion of limestone having a particle size of 0.25 mm or less was 19 wt. In order to limit the percentage to less than 0.2%, as in the prior art 1, it is necessary to develop a method of utilizing a particle having a particle size of 0.25 mm or less. According to Prior Art 2, 0.25 mm becomes unnecessary.
The following fine limestone is described as being able to be used for hot metal removal P, hot metal removal S, or vaporization removal P in a bottom-blowing converter. is there. It is also desirable from the viewpoint of the process operation that it can be used in the sinter production process.

Generally, the particle size composition of the sintering raw material that affects the productivity of the sinter ore is determined from the viewpoint of ensuring the air permeability in the raw material layer.
It is desirable that the grains are coarse within an appropriate range. From that point, about 10 wt. It is desirable that the particle size distribution of the limestone occupying around% or more is large for improving the productivity. By the way, according to Prior Art 3, a limestone to be blended having a particle size distribution of 3 to 5 mm using a charging device for forming a particle size segregation of sintering raw material of 10 to 30 wt. %, Improvement in productivity and improvement in reduced pulverization while maintaining the yield are achieved. However, when attention is paid only to a limestone having a particle size of 3 mm or less, the particle size distribution is not different from the conventional one. Therefore, depending on the particle size configuration of the raw material other than limestone, there is a possibility that the productivity and the reduction pulverizability may not be improved. According to the experimental results of the present inventors, it has become clear that the above fear may occur.

As described above, in the prior art, as a means for reducing the proportion of fine limestone in limestone, fine limestone is removed by sieving and the fine limestone is discharged out of the sinter production process. It can be seen that the particle size distribution of the fine lime particles other than the coarse limestone particles is not different from the conventional one even if it is used as a basic step or the coarse limestone particles are limited to a required range and mixed and added. It is necessary to eliminate problems in sinter production caused by such matters.

Next, the use technology of the highly crystalline water ore will be described. In this regard, as described above, in order to remove the water of crystallization in advance, or to control and suppress the generation of the initial melt in sintering, to optimize the composition of the slag-forming component in the sintering compounding raw material, It relies on appropriate pretreatment of highly crystalline water ores. And there is no technology that focuses on the limestone particle size in the sintering compound raw material.

Therefore, an object of the present invention is to provide a limestone which is received from a mine supplying limestone, without changing its particle size distribution from the conventional one, and in a standard operation of sinter ore production, a fine-grained area occupying the limestone. A limestone having a reduced particle size distribution, for example, a particle having a particle size of (0.25 to 1) mm or less is used, and the reduced amount of limestone is used without being discharged out of the sinter production process. Based on the premise that the strength of sinter and product yield are maintained at required values,
It is an object of the present invention to develop a sinter ore production technique capable of improving productivity and reducing pulverizability. Furthermore, even when the particle size distribution of each sintering raw material other than limestone fluctuates in practical use, the balance between the strength and product yield of the sinter and the productivity and reduced powderability is improved. An object of the present invention is to develop a technology for producing a sintered ore that can be maintained.

Thus, an object of the present invention is to solve the above-mentioned problems and to produce a sintered ore in which the strength and the yield are secured by the downward suction type sintering machine and the reduced pulverizability is improved by the conventional method. It is an object of the present invention to provide a method for producing a sintered ore for a blast furnace for producing the sintered ore with high efficiency.

[0020]

Means for Solving the Problems The inventors of the present invention have conducted the following studies from the above viewpoints, and have obtained the following findings.

First, the opening of the sieve in the limestone crushing process was changed from 3 mm to 5 mm in the conventional method, and the ratio of limestone having a particle size of 3 to 5 mm in the limestone was reduced to 8 wt. % To 34 wt. %, And the remainder is mixed with limestone composed of limestone with a particle size distribution of 3 mm under as usual and other sintering raw materials at a predetermined mixing ratio, and mixed and granulated by a conventional method to form a pseudo. The particles are prepared and charged into a downward suction type sintering machine using a particle size segregation forming charging device,
It was fired under standard operating conditions. In this way, the effect of increasing the proportion of limestone having a particle size of 3 to 5 mm on the improvement of the productivity of sinter and the improvement of the reduction pulverizability of the conventional method and the present test method was found to be almost ineffective. I couldn't. As a result of the analysis and examination of the test results, the reason why the above-mentioned effect was not clearly observed was that the particle size distribution of those having a particle size of 3 mm or less was the same as that of the conventional limestone despite increasing the proportion of limestone having a particle size of 3 to 5 mm. Was used.

Therefore, limestone having a particle size distribution under 3 mm and having the same particle size distribution as conventional limestone is treated by a sieving apparatus, and only limestone having a particle size under 0.25 mm is targeted at an average particle size of 1.7 mm. Pseudo-particles were granulated, and a blended raw material was prepared by adding this as a part of the original limestone blending ratio in the blended raw material. A test for producing a sintered ore was performed using the blended raw materials thus prepared. The sintered ore produced in this way maintained the strength control level, and the product yield maintained the conventional level. In addition, they have found that there are effects of improving productivity and reducing pulverizability.

The present inventors further performed the same test as described below, except that the opening of the sieving apparatus was changed from 0.25 mm to 1 mm under the above-mentioned sinter production test conditions. As a result, the effects of improving the strength level and product yield of the sinter, as well as the productivity and reduced pulverizability, were further increased.

The present invention has been made based on the above findings, and the gist is as follows. That is, in the method for producing a sintered ore for a blast furnace according to claim 1, limestone is compounded with iron ore together with other raw materials for compounding, water is added, granulated into pseudo-particles, and the obtained pseudo-particles are lowered. In the method for producing a sintered ore to be sintered by a suction type sintering machine, the limestone is cut out from a mixing tank of the limestone, and the cut out limestone is sieved. It is blended with other ingredients for blending, while the limestone under the sieve is granulated in advance into granules of limestone by a granulator, and the obtained limestone pseudo particles are treated in the same manner as the limestone on the sieve. Blended with iron ore and other ingredients for blending. Thus, a blending raw material is prepared in which the limestone on the sieve and the limestone under the sieve that has been previously quasi-particled are blended with iron ore and other blending raw materials. Next, water is added according to a conventional method, mixed and granulated to prepare pseudo particles for sintering. The simulated particles for sintering thus prepared are charged into a downward suction type sintering machine as a sintering raw material to produce sinter for a blast furnace.

According to a second aspect of the present invention, there is provided an operation method for producing a sinter for a blast furnace.
The limestone cut from the mixing tank in the sinter production process described in the above is blended with iron ore and other raw materials for compounding without sieving, and prepared into pseudo particles for sintering, and thus obtained. The method is characterized in that the sintering pseudo-particles are sintered by a downward suction type sintering machine, and the sinter production process is switched as needed to operate.

According to a third aspect of the present invention, there is provided a method for manufacturing a blast furnace sintered ore according to the first aspect, wherein the branching point of the limestone sieving particle size is 1 mm, 0.5 mm or 0.25 m.
The characteristic feature is that sinter is produced as m.

According to a fourth aspect of the present invention, there is provided the operation method for producing a sinter for a blast furnace according to the second aspect, wherein the branch point of the limestone sieved particle size is 1 mm, 0.5 mm or 0.25 mm.
It is characterized in that it operates in the production of sinter ore as mm.

According to a fifth aspect of the present invention, in the method for producing a blast furnace sintered ore according to the first or third aspect, the pseudo particles for sintering are charged into a pallet of a downward suction type sintering machine. As a charging device, the charging is performed using a charging device having a function of forming a grain size segregation in the thickness direction of the raw material layer on the pallet, thereby producing a sintered ore.

According to a sixth aspect of the present invention, there is provided an operation method for producing a sinter for a blast furnace according to the second or fourth aspect, wherein the pseudo particles for sintering are charged into a pallet of a downward suction type sintering machine. It is characterized in that the pallet is charged by using a charging device having a function of forming a grain size segregation in the thickness direction of the raw material layer on the pallet, and the sinter is manufactured.

In a seventh aspect of the present invention, there is provided a method for producing a sintered ore for a blast furnace according to the fifth aspect, wherein the CaO concentration in the raw material charged on the pallet by the charging device having the function of forming a particle size segregation. The distribution in the raw material layer thickness direction,
It is characterized in that a sintered ore is produced by forming a high concentration from an upper layer portion toward a lower layer portion.

According to an eighth aspect of the present invention, there is provided an operation method for producing a sinter for a blast furnace according to the sixth aspect, wherein the CaO concentration in the raw material charged on the pallet by the charging apparatus having the function of forming the particle size segregation is provided. The distribution of the raw material layer in the thickness direction is formed so as to increase in concentration from the upper part to the lower part, and the sinter production is operated.

The method for producing a sintered ore for a blast furnace according to the ninth aspect is the production method according to the first, third, fifth or seventh aspect,
4 mass% of crystallization water as iron ore in the compounding raw material
The iron ore containing the above is blended in the main raw material in an amount of 25 mass% or more to produce a sintered ore.

According to a tenth aspect of the present invention, there is provided the operation method for producing a blast furnace sinter according to the second, fourth, sixth, or eighth aspect, wherein the iron ore in the compounding raw material comprises 4mass of crystallization water.
The iron ore containing s% or more is blended in the main raw material in an amount of 25 mass% or more to operate sinter production.

Here, the iron ore in the blended raw material refers to blending powder (B powder) and plain iron ore, and the main raw materials are iron ore, returned ore, and the like.

[0035]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sinter ore production flow for a blast furnace for explaining an example of an embodiment of a method for producing a sinter ore and an operation method for sinter ore production according to the present invention. Fine ore 1, limestone 2,
The raw materials of silica stone 3, coke breeze 4, returned ore 5 and other miscellaneous raw materials 6 are cut out from the respective mixing tanks 7, and water 9 is added to the mixed raw materials 8 mixed at a predetermined ratio, and
Then, the mixture is processed by the granulator 11 to form pseudo particles. Further, coke breeze 12 is appropriately added, and the mixture is treated by the coating mixer 13. Pulverized sintering raw material 1 in the form of pseudo particles
4 is charged into a sintering machine 15 and sintered to agglomerate. When charging the pseudo particles for sintering to the pallet of the sintering machine 15,
A charging apparatus having a segregation forming function in the thickness direction is used so that the particle size distribution in the thickness direction of the raw material layer is coarse in the lower layer and fine in the upper layer. By segregating the particle distribution of the sintering raw material in this manner and increasing the fuel coke distribution in the upper layer compared to the lower layer, it is effective in improving the quality and productivity of the sinter. . After mining from the sintering machine, hot crushing and cooling, crushing and sizing are performed to obtain a sintered mineralized product.

The basic feature of the present invention is that, in the above-mentioned process, limestone 2 as a raw material is cut out from the mixing tank 7 with the particle size distribution unchanged from the conventional one. As described above, as a pretreatment of the raw material limestone 2, the raw material limestone 2 is sieved by the sieving device 16, and the obtained undersized limestone 17 having a predetermined particle size or less is granulated by the small granulator 18. In addition, as a method of the sieving device 16, as a device suitable for sieving fine particles, instead of a conventional vibrating screen, if a jumping screen of a method of tensioning and relaxing the screen itself is used, up to limestone of finer particle size, This is desirable because sieving can be performed without clogging trouble. Thus, the sieved limestone 17 containing fine limestone
Limestone Pseudo-particles 1 with the particle size distribution changed in the larger direction
Prepare to 9. This is to mix it with other compounding raw materials like the limestone 20 on the sieve.

According to this method, of the limestone 2 received by the sintering plant, for example, -0.5 mm or-
The particle size distribution of the fine limestone such as 0.25 mm is raised by an appropriate amount to reduce the mixing ratio of the fine limestone. Of course, the same effect can be obtained by raising the particle size distribution in the fine grain portion of -1 mm. This solves the problem of developing a method for utilizing the limestone in the sintering process, which is a problem when trying to reduce the proportion of fine-grained limestone in the compounding material for sintering. You. -0.25mm, -0.5mm as fine limestone
Or if limestone with a particle size of -1 mm is turned into pseudo particles,
This is advantageous for the effect of improving the reduction pulverizability of the sintered mineral product.

Further, as proposed in the above-mentioned prior arts 2 and 3, the limestone 2 received by the sintering plant is sieved in order to improve the reduction pulverizability, and the limestone 2 is simply coarse-grained limestone. In the case of limestone with a particle size composition by simply increasing the proportion of limestone and decreasing the proportion of fine-grained limestone,
The particle size distribution focusing only on the fine-grained limestone is similar to the conventional one and has not changed at all. That is, in this case, the minimum particle size in the fine limestone does not change from the conventional level. It is difficult to improve the tendency of the reduction pulverizability to deteriorate due to this. However, the problem can be solved by preliminarily sieving limestone and granulating limestone of the present invention.

Next, the operation method of the present invention for producing sinter is as follows.
As shown in the sinter production flow of FIG.
Is passed through a limestone pre-treatment step 21 in which (A) a sieving treatment as a pre-treatment and a granulation treatment of fine limestone accompanying the limestone pre-treatment are carried out, and then a production process (hereinafter, referred to as a “mixing raw material”). Manufacturing process A ”) and (B)
A production process (hereinafter, referred to as a limestone pre-treatment process 21) in which the limestone is directly blended with other blending raw materials without being used.
The operation is switched at any time from “manufacturing process B”.

Here, the selection and switching of the production process A or the production process B are performed based on the results of the quality control standards of the sintered mineral products, the quality characteristics and level of each raw material for compounding used, the supply / demand situation, the production process, and the like. Considering the plan, the temperature distribution, air permeability, and firing state of the sintering raw material layer of the pallet are determined and determined. In addition, as the characteristics of the product quality, attention is paid particularly to a good balance between strength and reduced powderability, and the characteristic factors of each raw material for compounding are, in particular, the chemical composition and particle size distribution of iron ore, limestone. Consider the chemical component composition and particle size of minor raw materials, such as excluding auxiliary raw materials and mill scale, and the particle size of coke breeze, etc., and ensure productivity in connection with the production process plan. In this way, by operating the method of appropriately switching between the manufacturing processes A and B, the product quality is stabilized, the raw material cost and the operating cost are saved, and the production process operation is stabilized.

In the present invention, the raw material limestone for blending is used as a raw material for blending after being pre-treated as described above.
When charging the pallet, a segregation charging apparatus in the thickness direction is used so that the particle size distribution in the thickness direction of the raw material layer on the pallet is such that coarse particles are distributed more in the lower part and fine particles are distributed more in the upper part. Thus, when the raw limestone for blending is pre-treated, that is, the particle size under the sieve is, for example, -1 mm, -0.5 m
m, or -0.25 mm granulated fine limestone to prepare limestone pseudo-particles, thus increasing the average particle size of the fine limestone and blending with other raw materials, granulated from this blended raw material The pseudo-particles obtained are subjected to the internal state of the raw material layer thickness when the layer thickness direction segregation charging apparatus is used, that is, the particle size distribution in the layer thickness direction (however, true in the granulation steps 10 to 13 shown in FIG. 1). Particle size distribution including particles and limestone pseudo-particles remaining), morphology and distribution of limestone attached to pseudo-particles, and CaO component distribution in layer thickness direction are different from those in the case where limestone is not pre-treated. It is clear.

As a result of various studies and considerations, the present inventors
The following conclusions were obtained.

By adding the above-described limestone pretreatment step, the grain size distribution in the layer thickness direction in the raw material layer on the pallet of the sintering machine becomes larger in the upper part compared with the case where the limestone pretreatment step is not added. The proportion of fine grains occupying further decreases, while the proportion of coarse grains occupying the lower part further increases. Furthermore,
It was concluded that the amount of limestone in the thickness direction, and thus the CaO concentration, was lower in the upper part and higher in the lower part. In FIG.
Regarding the particle size distribution in the layer thickness direction in the raw material layer on the pallet of the sintering machine, the conventional method (FIG. 3A) and the method of the present invention (FIG.
FIG. 3 is a diagram schematically comparing (b)), and FIG. 3 shows an estimation of a CaO concentration change in a layer thickness direction by a conventional method (FIG.
(A)) and a diagram comparing the method of the present invention (the same figure, (b)). As described above, in the lower suction type sintering machine, in the upper part of the raw material layer, the temperature tends to increase due to the decrease in the endothermic reaction accompanying the decomposition reaction due to the reduction in the amount of limestone, and the strength of the sintered mineral product And the yield is improved. On the other hand, in the lower part of the raw material layer, the permeability is improved by increasing the amount of coarse-grained limestone, and the cooling rate is further improved, so that the productivity and the reduction pulverization property are improved.

As described above, quasi-granularization of limestone having a finer grain size is helped by the effect of improving the permeability in the sintering material layer in the pallet, and the deterioration of the permeability when a large amount of highly crystalline water ore is used is alleviated. I also confirmed that.

[0046]

According to the present invention, the grain size distribution of limestone for sintering raw materials is coarsened in order to secure the strength and yield of sintered mineral products, and further improve the productivity and the reduction pulverizability. In the method of adjusting in the direction, conventionally, limestone in a fine-grain area, for example,-
0.5 mm or -0.25 mm of fine limestone is discharged out of the sintering process, and there is no effective method for its use. All limestone can be used as a raw material for sinter production. Also, taking into account the quality and characteristics of raw materials at the time of sinter production, the supply and demand of raw materials, and the production process plan, compare the quality control standards with current quality results,
In addition, it is possible to judge whether or not the pretreatment of the limestone is necessary according to the operation result other than the quality, and perform the cost reduction operation. Furthermore, the particle size distribution and component concentration distribution of the raw material on the sintering machine pallet in the layer thickness direction are further improved, and a better balance between product strength and yield assurance, productivity improvement and reduction powdering property improvement is achieved. Can be taken. Furthermore, the improvement of air permeability in the sintering bed by such a limestone particle size control technique stabilizes the operation of blending a large amount of highly crystalline water ore. Therefore, it is possible to smoothly respond to the raw material supply trend and reduce the raw material cost. ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the above-mentioned sintered ore for blast furnaces, and the operation method regarding the production of sintered ore for blast furnaces can be provided, and an industrially useful effect is brought.

[Brief description of the drawings]

FIG. 1 is a sinter ore production flow for a blast furnace for describing an embodiment of a method for producing a sinter ore and an operation method for sinter production according to the present invention.

FIG. 2 is a schematic diagram comparing a particle size distribution in a layer thickness direction in a raw material layer on a sintering machine pallet with a conventional method and the present invention method.

FIG. 3 CaO in the thickness direction of the raw material layer on the pallet of the sintering machine
FIG. 5 is a diagram showing a comparison between a conventional method and a method according to the present invention regarding a change in concentration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fine ore 2 Limestone 3 Silica 4 Coke breeze 5 Return ore 6 Other miscellaneous raw materials 7 Blending tank 8 Blended raw material 9 Water 10 Mixer 11 Granulator 12 Granulated coke 13 Coating mixer 14 Sintering raw material 15 Sintering machine 16 Sieving device 17 Limestone under sieve 18 Small granulator 19 Limestone pseudo-particle 20 Limestone on sieve 21 Limestone pretreatment process

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideaki Sato 1-2-1 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 4K001 AA10 BA02 CA34 CA39 CA41 GA10 GB02

Claims (10)

[Claims] 1. A sinter in which limestone is mixed with iron ore together with other raw materials for mixing, water is added, granulated into pseudo-particles, and the obtained pseudo-particles are sintered by a downward suction type sintering machine. In the manufacturing method, the limestone is cut out from the limestone blending tank, the cut limestone is sieved, the limestone on the sieve is blended with the iron ore and other raw materials for blending, and the limestone under the sieve is This is granulated into limestone pseudo-particles, and the obtained limestone pseudo-particles are blended with the iron ore and other compounding raw materials. Thus, the limestone on the sieve and the limestone under the sieve are both the iron ore and the other. A sintering ore for a blast furnace, characterized in that pseudo-particles for sintering are prepared from the raw material for mixing and the raw material for mixing, and the pseudo-particles for sintering thus prepared are used as a raw material for sintering. 2. A process for producing a sinter according to claim 1 and a process for producing a sinter according to claim 1, wherein the limestone cut from the mixing tank is not sieved, and iron ore and other limestone are removed. The production process of sinter, which mixes with the raw materials for compounding and prepares pseudo-particles for sintering, and sinters the pseudo-particles for sintering thus obtained with a downward suction type sintering machine, is switched as needed to operate An operation method for producing sinter for a blast furnace, comprising: 3. The branching point of the limestone sieving particle size,
2. The method according to claim 1, wherein the distance is 1 mm, 0.5 mm, or 0.25 mm.
A method for producing a sintered ore for a blast furnace according to the above. 4. The branching point of the limestone sieving particle size,
The thickness is set to 1 mm, 0.5 mm or 0.25 mm.
An operation method for producing a sintered ore for a blast furnace as described above. 5. A charging device having a function of forming a grain size segregation in the thickness direction of a raw material layer on the pallet when charging the sintering pseudo particles into a pallet of the downward suction type sintering machine. 4. The method for producing a sintered ore for a blast furnace according to claim 1 or 3, wherein: 6. A charging device having a function of forming a grain size segregation in a thickness direction of a raw material layer on the pallet when charging the sintering pseudo particles into a pallet of the downward suction type sintering machine. The operation method for producing a sinter for a blast furnace according to claim 2 or 4, wherein 7. The distribution of the CaO concentration in the raw material loaded in the pallet in the raw material layer in the thickness direction of the raw material charged into the pallet by the charging device having the function of forming the particle size segregation becomes higher from the upper part to the lower part. The method for producing a sintered ore for a blast furnace according to claim 5, wherein the sinter is formed as follows. 8. The distribution of the CaO concentration in the raw material charged into the pallet loaded in the pallet by the charging device having the particle size segregation forming function in the thickness direction of the raw material layer becomes higher from the upper part to the lower part. The operation method for producing a sinter for a blast furnace according to claim 6, wherein the sinter is formed as described above. 9. An iron ore containing 4 mass% or more of crystallization water as the iron ore in the raw material is 25 ma in the main raw material.
Claims 1 and 3, characterized in that ss% or more is blended.
8. The method for producing a blast furnace sintered ore according to 5 or 7. 10. The iron ore in the compounding raw material,
Iron ore containing 4 mass% or more of crystallization water in the main raw material 25m
ass% or more, characterized in that:
The operation method for producing a sinter for a blast furnace according to 4, 6, or 8.