WO2015005218A1 - Method for producing granulated raw material for sintering applications - Google Patents

Abstract

[Problem] To granulate adequate quasi-particles which can be used as a compounding raw material for use in the production of a sintered ore, while preventing the production of coarse granulated particles (quasi-particles) having irregular particle diameters and weak bond strength during the granulation. [Solution] A method for producing a granulated raw material for sintering applications from a sintering/compounding raw material comprising an iron ore fine powder such as a pellet feed, said method comprising: subjecting the sintering/compounding raw material to a mixing treatment for homogeneously dispersing each of the iron ore fine powder and water using a high-speed mixer such as an Eirich mixer; and subsequently subjecting the resultant product to a granulation treatment while stirring and mixing the product using a drum mixer and/or a pan pelletizer.

Description

Method for producing granulated raw material for sintering

The present invention relates to a method for producing a granulating raw material for sintering used in a DL type sintering machine.

Sintered ore consists of several brands of fine iron ore (generally called sinter feed of about 125-1000μm), auxiliaries such as limestone, quartzite, and serpentine, dust, scale, return ore, etc. Sintered blended raw material powdered with an appropriate amount of powdered coke and other solid fuel, mixed with water, granulated, and the resulting granulated raw material was charged into a sintering machine. Manufactured by firing. Generally, the sintered blending raw material contains moisture, and aggregates into pseudo particles during granulation. This pseudo-granulated raw material for sintering, when placed on the pallet of the sintering machine, helps to ensure good ventilation of the sintered raw material charging layer and facilitates the sintering reaction. Proceed to

By the way, in recent years, powder iron ore for sintering has been lowered in quality by depletion of high-quality iron ore. That is, the lower grade of iron ore leads to an increase in slag components and a tendency to pulverization, and therefore the granulation properties are decreased due to an increase in the alumina content and an increase in the pulverization ratio. On the other hand, sintered ore used in the blast furnace is required to have a low slag ratio, high reducibility, and high strength from the viewpoint of reducing hot metal production cost in the blast furnace and reducing CO ₂ generation amount. .

In such an environment surrounding powdered iron ore for sintering, high-quality sintered ore is produced using the hardly granulated fine iron ore that has been used for pellets recently called pellet feed. Techniques for this have been proposed. For example, one of these conventional techniques is the Hybrid Pelletized Sinter method (hereinafter referred to as “HPS method”). In this technology, low-slag-ratio, highly-reducible sintered ore is produced by granulating a sintering compounded raw material containing a large amount of fine iron ore such as pellet feed using a drum mixer and pelletizer. (Patent Literature 1, Patent Literature 2, Patent Literature 3, Patent Literature 4, Patent Literature 5).

In addition, prior to the sintering raw material powder granulating step, a method of conditioning and mixing with a high-speed rotary mixer (Patent Document 6), and prior to the granulating step, fine iron ore and iron dust are preliminarily mixed with a stirring mixer. There are also proposals such as a method of mixing (Patent Document 7) and a method of mixing fine powder (pellet feed) in advance with an Eirich mixer and then granulating with a drum mixer (Patent Document 8).

Japanese Patent Publication No.2-4658 Japanese Patent Publication No. 6-21297 Japanese Patent Publication No. 6-21298 Japanese Patent Publication No. 6-21299 Japanese Patent Publication No. 6-60358 JP 60-52534 A JP-A-1-312036 JP-A-7-331342

However, the sintered blending raw material containing a large amount of fine iron ore, particularly ultra fine iron ore such as pellet feed, is granulated using the HPS method as described in Patent Documents 1 to 5, In the method of mixing in advance using a high-speed stirrer as described in Patent Documents 6 to 8, there are the following problems. As shown in FIG. 1, in these methods, not only fine particles (less than 0.5 mm) but also large (greater than 10 mm) pseudo particles are generated. The reason is that fine iron ore like pellet feed, if the wettability is the same, the finer the specific surface area, the greater the specific surface area, so it is easy to absorb moisture and hold more moisture between the powders. It is because each fine iron ore becomes easy to absorb moisture preferentially. As a result, it is easy to generate coarse pseudo particles in which the fine particles are simply aggregated or coarse particles having irregular particle sizes in a form in which the fine particles adhere around the core particles. Furthermore, these methods also have problems of adhesion of powder, poor uniform dispersion of fine powder and moisture, and a decrease in equipment operation rate.

This point is also clear from the following experiment conducted by the inventors.
First, in this experiment, granulation was performed using a blended raw material containing finely granulated iron ore (vanadium content: 40 mass%) such as pellet feed, and at this time, the generated granulated particles (pseudo particles) ) And the particle size distribution of the pellet feed. The result is shown in FIG. First, as shown in FIG. 2 (a), those containing a large amount of pellet feed in the sintered blending material have a higher proportion of coarse particles (over 8 mm) than those containing no pellet feed. . The weight ratio reached about 75 mass%. In addition, the particle size distribution of the pellet feed in the granulated pseudo particles (FIG. 2B) showed the same tendency as the particle size distribution of the granulated particles (FIG. 2A). That is, the ratio of the pellet feed in the coarse grains was as high as about 80 mass%, and it was found that most of the pellet feed was unevenly distributed in the coarse grains. From this, it can be seen that coarse pseudo-particles are formed by aggregation of pellet feeds. And it turned out that this pseudo particle which belongs to a coarse-grain area | region also has a high moisture content (FIG.2 (b)). Therefore, the pellet feed is preferentially absorbed by the pellet feed, and therefore the pellet feeds aggregate to form coarse pseudo particles, and as a result, a large amount of moisture is absorbed in the coarse pseudo particles. It will be.

In this way, the blended raw material containing a large amount of fine iron ore such as pellet feed, when granulated, inevitably becomes uneven in particle size, and the fine powder is merely agglomerated, and the bond strength is weak. Coarse pseudo particles are easily generated. Therefore, when such pseudo particles are charged and deposited on the pallet of the sintering machine, as shown in FIG. 3 (a), the sintered raw material charging layer has a dense deposition structure and a bulk density. Becomes larger. Moreover, if such coarse pseudo-particles are deposited on a pallet of a sintering machine with a certain layer thickness, they are easily broken when a load (compressive force) is applied to the pseudo-particles. This leads to a decrease in porosity, which in turn causes deterioration in air permeability, which becomes an impediment to sintering machine operation. As a result, there is a possibility that the sintering time becomes long or the yield of the sintered ore is lowered and the productivity is lowered. Furthermore, the amount of quicklime, which is a binder used for granulation, must be increased, leading to an increase in the production cost of sintered ore, or when coating solid fuel such as powdered coke in the subsequent process. As a result, non-uniformity of the existing state of the powdered coke or the like as the whole raw material is caused. As a result, combustion and poor heat receiving are caused and the firing rate is lowered.

The object of the present invention is that when granulated iron ore is used as a raw material for the production of sintered ore, coarse granulated particles (pseudo particles) having irregular particle sizes and weak bond strength are generated during granulation. The object is to propose a method to prevent and granulate proper pseudo particles.

That is, the present invention is based on pseudo-particles having a relatively uniform particle size and a small particle size distribution, in which fine iron ore and fine particles are firmly aggregated, or in a structure in which fine iron ore or the like is adhered around the core particles. The manufacturing method of the granulation raw material for sintering which becomes becomes is proposed. When the granulated raw material for sintering obtained by such a method is placed on a pallet of a sintering machine, the density of the sintered raw material charging layer formed on the pallet is reduced and the air permeability is improved. Thus, the firing time can be shortened, which is effective in improving the productivity of high-quality sintering.

Furthermore, the present invention produces sintered ore using such a granulating raw material for sintering, thereby improving the strength of sintered ore through improvement of combustion efficiency and melt generation conditions. It is possible to reduce the hot metal production cost and the amount of CO ₂ generated from the blast furnace.

As described above, the present invention is based on powdered iron ore (sinter feed), which is a conventional general sintering raw material (average particle size: a particle size showing about 50 μm in cumulative frequency distribution is about 1000 μm or more). In addition, fine iron ore (pellet feed) having an average particle size of about 40 to 100 μm and ultra fine iron ore (tailing ore) having a particle size distribution of 10 μm or less are also used as one of the raw materials for sintering. It is a proposal. In addition, FIG. 4 is a comparative graph of the average particle diameter of such various iron ore powders.

As described above, the sintered blending raw material containing a difficult-to-granulate fine iron ore (average particle size: 100 μm or less) such as pellet feed, when this is granulated, the powder, fine powder, and ultrafine powder moisture. Thus, coarse pseudo-particles having a weak bond strength tend to be preferentially aggregated with each other. Moreover, such pseudo particles often have a large particle size distribution (a state in which the difference in particle size is large and uneven), and the sintering material charging (filling) layer on the pallet is shown during operation of the sintering machine. As shown in FIG. 3 (a), the particles in the charging layer of the sintering raw material are coarsely and finely packed densely or irregularly and deteriorate the air permeability.

Therefore, in the present invention, prior to the granulating step by the drum mixer and / or the bread type pelletizer, pre-aggregation is performed using a high-speed agitator having a large agitating function to prevent preferential aggregation of fine and ultrafine iron ore. , Aim to uniformly disperse each of the fine iron ore and water, and finally prevent the generation of coarse pseudo-particles with low bond strength, and the particle size is relatively uniform, the particle size distribution is small, and the bond strength We have developed a method for producing strong pseudo-particles.

That is, the present invention relates to a method for producing a granulated raw material for sintering from a sintered blending raw material containing fine iron ore, and as the sintering blended raw material, 5-50 mass% pellet feed or fine iron ore that is tailing ore. Stone, sintered iron ore that is a sinter feed, and other raw material powder, miscellaneous raw material powder and sintered fuel material containing at least one of solid fuel powder, and using the high-speed stirrer, this fine iron ore A method for producing a granulation raw material for sintering, characterized by carrying out uniform dispersion treatment on stone and moisture, respectively, and stirring and mixing using at least one of a drum mixer and a pan-type pelletizer. According to this method, as shown in FIG. 3 (b), granulated particles of uniform size are filled, and a state in which voids are maintained can be maintained, which is advantageous for ensuring air permeability. is there.

As a more preferable solution of the present invention,
(1) In the above-mentioned uniform dispersion treatment of water, when the water content of the sintered blending raw material is small, water is sprayed in a range not exceeding the proper moisture value, while the water content of the sintered blending raw material is adjusted to the proper moisture value. If it is close to the water, it should not be sprinkled.
(2) The pellet feed is a fine iron ore having an average particle size of 40 μm to 100 μm, the tailing ore is a residue of fine iron ore having an average particle size of 10 μm or less, and Sinter feed is fine iron ore having an average particle size of 1000 μm or more,
(3) The high-speed stirrer is a crushing Eirich mixer having a crushing function of raw materials and coarse grains that have grown.
(4) The high-speed stirrer is installed before the drum mixer, or after the drum mixer and before the pan-type pelletizer,
(5) The crushing Eirich mixer has a stirring blade rotating at a high speed at a position eccentric in the radial direction with respect to the rotation center of the mixing pan,
(6) The rotation speed of the stirring blade is about 100 to 500 rpm,
(7) The auxiliary raw material powder is at least one selected from limestone, dolomite, silica, and serpentine,
(8) The miscellaneous raw material powder is any one or more selected from dust, scale, and return ore,
(9) The solid fuel powder is coke,
Can be considered.

(1) According to the present invention, it becomes possible to use a large amount of hardly granulated fine iron ore such as pellet feed and tailing ore as iron ore for sintering blended raw materials, and the particle size is still In addition, a granulated raw material for sintering having a small particle size distribution and high strength can be advantageously produced.
(2) Further, according to the present invention, since the uniform dispersion of fine iron ore and moisture can be effectively achieved during the stirring and mixing of the sintered blending raw material, the amount of binder used during granulation can be reduced. Can do.
(3) When the granulated raw material for sintering produced according to the present invention is charged and deposited on the pallet of the DL sintering machine, the density of the sintered raw material charged layer is reduced when the raw material is charged. As a result, it is possible to shorten the firing time accompanying the improvement of the air permeability and to improve the sintering productivity.

It is a comparison graph of the particle size distribution of the pseudo particle in the presence or absence of fine iron ore blending. It is a graph which shows the distribution of the pellet feed for every particle size of a pseudo | simulated particle (granulated particle), and the dispersion | distribution condition of a water | moisture content. It is a comparison figure of the conventional granulated particle deposition layer (a) and the granulated particle deposition layer (b) of the present invention. It is a comparison graph of the average particle diameter of a fine iron ore, a fine iron ore, and a super fine iron ore. It is a comparison figure of the granulation raw material manufacturing equipment for sintering which changed the installation position of the high-speed stirrer. It is a graph which shows the relationship between the stirring crushing position by a high-speed stirrer at the time of a granulation test, granulated particle average diameter, and air permeability. It is a graph which shows the relationship between the stirring crushing position by a high-speed stirrer at the time of a granulation test, a product yield, baking time, and a production rate. It is a basic diagram which shows an example of the stirring blade arrangement | positioning structure of a high-speed stirrer (Eirich mixer).

FIGS. 3 (a) and 3 (b) are schematic diagrams showing the structural characteristics of a pseudo particle deposition layer which is a granulation raw material for sintering. Conventional pseudo-particles as shown in FIG. 3 (a) are obtained by the method as shown in FIG. 5 (a). That is, in the conventional granulated raw material manufacturing process for sintering, the iron ore powder and auxiliary raw material powder cut out from the mixing tank are first mixed in the drum mixer 1, and then the mixed raw material is mixed with the bread-type pelletizer 2 It is a method of carrying out granulation processing by feeding to a granulator such as the above. In the mixing step and the granulation step, about 1 to 2 mass% of water is added, and the humidity is adjusted to obtain predetermined granulated moisture, thereby producing desired pseudo particles. In addition, 3 of illustration is an exterior coke and the exterior drum mixer of an auxiliary material.

On the other hand, the present invention having a pseudo-particle structure as shown in FIG. 3 (b) replaces the conventional granulating raw material manufacturing process for sintering, which includes a mixing step by a drum mixer and a granulating step by a pan pelletizer. As shown in FIG. 5 (b), before the mixing step by the drum mixer 1, the sintered blended raw material containing fine iron ore is first prepared by using a high-speed stirrer 4 such as an Eirich mixer. The purpose is to include steps of uniform dispersion (diffusion) and uniform dispersion of water. In addition, as shown in FIG. 5C, the present invention uses a high-speed stirrer 4 such as an Eirich mixer after the mixing process by the drum mixer 1 and before the pelletizer 2 to uniformly disperse the fine iron ore ( Diffusion) and a process of uniformly dispersing moisture.

In this way, in addition to the usual fine iron ore that is a sinter feed, the sintering blend contains a lot of the fine iron ore such as pellet feed and tailing ore (hereinafter referred to as fine fine iron ore including ultra fine tailing ore). In the case of raw materials, agglomerates and coarse pseudo-particles, in which only fine raw materials are gathered, are unloaded from the ship, unloaded to the raw material yard, and betting, which is a mixed treatment of several types of powder and fine iron ore. It is known that it is inevitably formed. If this is supplied as it is (without any treatment) and supplied to the drum mixer, mixing treatment and subsequent granulation treatment with the pelletizer 2 inevitably generate coarse agglomerated particles and pseudo particles with weak bond strength. Is a granulated raw material for sintering having a large particle size distribution width.

Therefore, in the present invention, the sintered blending raw material containing 5 mass% to 50 mass% of such fine iron ore is added before the stirring and mixing process in the drum mixer 1 as shown in FIG. As shown in FIG. 5 (c), before the granulation process by the pan pelletizer 2 after the drum mixer 1, an appropriate amount of water is supplied to the fine iron ore by the high-speed stirrer (Eirich mixer 4) without excess or deficiency. Therefore, both of them were uniformly dispersed. The reason is derived from the results of laboratory granulation tests described below. That is, at least before the final stage of the final granulation process, it is considered effective to uniformly disperse the sintered compounding raw material by uniform diffusion and addition of an appropriate amount of moisture according to the particle size and initial moisture. This is because the. For example, depending on the initial moisture value (about 0.1 to 10 mass%) of the sintered blending raw material, in order to obtain an appropriate moisture value (for example, about 7 mass%) suitable for high-speed stirring with a high-speed stirrer, When the initial moisture is low (0.1 to 5.5 mass%), water is sprayed during stirring. On the other hand, when the initial moisture of the sintering compound material is close to the appropriate moisture value (for example, 6.5 mass%), it is preferable to stop watering.

This experiment is shown in FIG. 5 from the viewpoint of when the high-speed stirrer should be used in order to achieve uniform dispersion in consideration of the uniform diffusion of the raw material, particularly fine iron ore, and the particle size of added water and the like. The processing of the flowchart as shown in the following: (a) the conventional method (without Eirich mixer), (b) the method where the Eirich mixer is installed in front of the drum mixer, (c) the Eilic mixer is installed after the drum mixer (however, , In front of the pelletizer), (d) a method in which the Eirich mixer is installed after the pelletizer, (e) an Eirich mixer is installed after the pelletizer, and sieved after the Eirich mixer treatment and only coarse particles 5 cases of the method of crushing In addition, the sintering compounding raw material used was a blending example of sinter feed: 80 mass%, pellet feed: 16 mass%, tailing ore: 4 mass%, and an Eirich mixer was used as a high-speed stirrer. The result is shown in FIG.

6 (a) and 6 (b) show the influence of air permeability due to the difference in the Eirich mixer installation position on the average diameter of each granulated particle. According to it, in the case (b) in which the Eirich mixer was installed in front of the drum mixer, the coarse particles (particles in which the fine particles were aggregated) were crushed and diffused, and the water was uniformly dispersed throughout, so the average particle size Was about 4.3 mm and proper particles. On the other hand, in the case (c) in which the Eirich mixer is installed after the drum mixer (but before the pan-type pelletizer), since the pulverization occurs after granulation, the sizing is promoted, but the average particle size is 4.25 mm. Slightly decreased. As for the air permeability index (JPU), the case (b) in which the Eirich mixer was arranged in front of the drum mixer gave better results. The case (d) in which the Eirich mixer was installed after the pelletizer had a slightly lower air permeability index than the case (b), and the Eirich mixer was installed after the pelletizer and only the coarse particles were crushed ( e) showed the same characteristics as the case (b).

Next, the granulation raw material for sintering produced by applying the above-mentioned four cases (be to e) with different installation positions of the Eirich mixer, which is a high-speed stirrer, is charged into a DL sintering machine and sintered. Each item of yield, sintering time, and production rate when producing ore was evaluated. The results are shown in FIGS. 7 (a) to (c).

As shown in FIG. 7, the case (b) in which the Eirich mixer is arranged in front of the drum mixer has improved air permeability and the sintering reaction proceeds uniformly, so that the firing time is shortened and the productivity is improved. It became high. On the other hand, in the case (c) in which an Eirich mixer was installed after the drum mixer, the sintered ore was produced using the granulation raw material for sintering obtained in this case. Although the average particle size of the particles became small, the air permeability was improved because the particle size distribution was improved, and the sintering reaction proceeded uniformly, so the firing time was shortened and the productivity was increased. In case (d) in which the Eirich mixer is installed after the pelletizer, the average particle size of the granulated particles is the same as in case (b), but the particle size is uneven and air permeability is insufficient and sintering is performed. The reaction became non-uniform, the firing time became longer, and the productivity decreased.

Overall evaluation of the above experiment shows that good results can be obtained when the high-speed stirrer (Eirich mixer) is installed before the drum mixer or before the pan-type pelletizer after the drum mixer. These methods are adopted as the method of the present invention.

In the experiment, an Eirich mixer was used as a high-speed stirrer. This Eirich mixer is known as a high-speed agitation granulator, and has a function of pulverizing and diffusing particles, particularly coarse particles, and a function of agglomeration of particles due to liquid crosslinking and agglomeration accompanying growth.

In the present invention, it was decided to use a facility configuration that emphasized the high-speed stirring function of the Eirich mixer. That is, the high-speed stirrer suitable for the present invention has a plurality of stirrers at positions slightly deviated in the radial direction with respect to the rotation center of the mixing pan 5 (positions where coarse pseudo particles tend to stay, decentered in the clockwise direction). As shown in FIG. 8, the blades 6 are of a structure that is radially shifted in the vertical direction, and when the raw materials are efficiently stirred and mixed while preventing the rotation of the stirring blades and the raw materials, granulation is performed. Rather than the action, it enhances the crushing-diffusion action of the sintered compounding raw material and the produced particles. By having such a structure, uniform dispersion (diffusion) of fine iron ore itself, uniform dispersion by effective supply of added moisture (sprinkling) according to the initial moisture and particle size distribution of raw materials, coarse grain crushing, Granulation can be achieved.

The speed of the stirring blade can be freely changed from a high speed that exhibits a high shearing force to a low speed at which granulation is performed by gentle stirring. In particular, the present invention increases the stirring speed. Crushing of raw materials, strong agitation of fine iron ore (diffusion), supply of appropriate amount of water according to particle size and initial moisture value, that is, uniform diffusion of water, dispersion and mixing, partial grain growth (granulation) There is a feature in the equipment configuration that encourages In addition, it is considered that when the stirring blade is operated at a medium to low speed side, grain growth and sizing is promoted, and the raw material crushing action is somewhat sacrificed.

By the way, in the prior arts (Patent Documents 6 to 8), even when a high-speed stirrer is used, the humidity is adjusted without taking into consideration the appropriate moisture value at the time of high-speed stirring. Moisture increases, adhesion to the stirrer and blades increases, and the load current value increases. As a result, there is a problem in that the shearing force of the stirrer is reduced, leading to a reduction in the crushing force of the raw material, leading to deterioration of the particle size distribution.

In this regard, in the present invention, for example, the raw moisture content is monitored so that the initial moisture value of the combustion blended raw material charged into the high-speed stirrer can be constantly maintained at a level lower than the appropriate granulated moisture value (for example, about 7 mass%). If the initial moisture value of the raw material is close to the appropriate moisture, watering is stopped in the high-speed stirrer. It was to be.

As a result, it is possible to effectively suppress the adhesion of raw materials in a high-speed stirrer and to exhibit an excellent stirring effect as compared with the conventional method. That is, it is possible to efficiently reduce the coarse particles in the granulated particles by adding the granulation operation after sufficiently reducing the moisture in the raw material, particularly the moisture on the coarse particle side. From this, in order to improve sintering productivity in this invention, it was suggested that controlling the particle size distribution of granulated particles appropriately is also important. That is, an appropriate particle size distribution is a distribution in which the ratio of coarse particles and ungranulated powder is low.

For the purpose of strengthening the crushing function by high-speed stirring and the uniform dispersion characteristic of the present invention, it is recommended that the rotation speed of the stirring blade be 100 rpm to 500 rpm, preferably 150 rpm to 350 rpm. This is because a stirring effect or the like cannot be obtained at a slow speed of less than 100 rpm. In this case, the rotation speed of the mixing pan 5 as the main body is operated at a constant speed of about 15 rpm in any case, and the number of the stirring blades 6 is about 8 to 32. Applies.

Note that the mixing pan 5 is a rotating cylindrical flat container that moves the entire raw material, so that all the raw materials in the mixer are constantly flowing. In addition, a scraper 7 is usually installed in the high-speed stirrer. The scraper 7 is positioned above the mixing pan 5, and has a role of peeling off the raw material that is to remain on the inner wall or the bottom of the mixing pan 5 and continuously feeding the raw material to the stirring blade 6. In particular, the raw material to be retained at the bottom is also peeled off by a bottom scraping chip (not shown) attached to the lowermost end of the stirring blade, but is preferably used together with the scraper 7.

On the other hand, in the case of using an Eirich mixer in which the rotation speed of the stirring blade was 80 rpm and the number of stirring blades was 8, a large amount of coarse pseudo particles was observed, and the average diameter of the pseudo particles was 4. The weight ratio of the pseudo particles was as large as about 5 mm, about 13%, which was not different from the conventional method.

When producing a sintered ore using a granulating raw material for sintering produced based on the method of the present invention, an effect of improving the yield of sintered ore and the strength of the sintered ore can also be expected. This is because in the conventional method, powder coke is coated on pseudo particles with non-uniform particle size, so that combustion and heat reception become non-uniform and yield decreases, but it was manufactured by applying the present invention. In the case of a granulated raw material for sintering, since the particle size becomes relatively uniform, the existence state of the powder coke is also optimized. In addition, when not implementing external granulation of powder coke, uniform mixing before granulation is necessary to achieve uniform mixing of powder coke and limestone, but in the case of the present invention, such a burden is reduced. The

This example was carried out by a method according to the equipment flow shown in FIG. As sintering raw materials used in this example, as the sinter feed, 50 mass% of Australian iron ore (average diameter 3.8 mm) and 50 mass% of South American iron ore (average diameter 2.7 mm) were used. In addition, when blending fine iron ore that is pellet feed, especially when blending more than 20 mass%, the above blending ratio (1: 1) of Australian iron ore and South American iron ore is transferred to these without changing. I responded. In addition, as the fine iron ore, tailing ore (residue generated in the process of producing pellet feed) was also used as part of the fine iron ore. This sintering compound material was based on a basicity of 2.0.

The high-speed stirrer was installed in front of the drum mixer or in front of the pelletizer after the drum mixer, and the operation changed depending on the sintering raw materials and operating conditions, so external monitoring was strengthened. In particular, the main purpose was to control the rotation speed of the stirring blades of the high-speed stirrer, and in addition, by adjusting the clearance with the bottom surface of the mixing pan, it was operated with the aim of uniform dispersion of the fine iron ore and pseudo particles to be stirred. . Therefore, in this embodiment, a thickness measuring device such as a laser displacement meter is also used. And the magnitude | size of the fine iron ore and pseudo particles which should be stirred, ie, the degree of crushing, was adjusted by adjusting the rotational speed of this stirring blade.

An Eirich mixer was used as a high-speed stirrer. The diameter of the mixing pan of the Eirich mixer used was 0.75 m, the number of rotations (counterclockwise) was 15 rpm, and the stirring blades (eccentric distance from the center of the pan: 115 mm) were the number of rotations: 250 rpm and the number of stirring blades: Eight were used. The direction of rotation of the stirring blades was opposite to the direction of rotation of the mixing pan in order to prevent the raw material from rotating. In addition, the clearance between the tip of the stirring blade and the inner bottom surface of the mixing pan was set to about 8 mm as a reference for efficiently crushing coarse particles having a particle diameter of 8 mm or more. As a result, the pseudo particles were reliably crushed in any of the coarse particles having a particle diameter of 8 mm or more. The obtained granulated pseudo particles had an average diameter of 4.3 mm, and a desired granulation raw material for sintering was obtained.

The production technique according to the present invention can be applied not only to the production of a granulation raw material for sintering but also to the production technique of agglomerated ore for blast furnace.

DESCRIPTION OF SYMBOLS 1 Drum mixer 2 Bread-type pelletizer 3 Exterior coke, auxiliary material exterior drum mixer 4 High-speed stirrer 5 Mixing pan 6 Stirring blade 7 Scraper

Claims (10)

In the method of producing a granulation raw material for sintering from a sintering blended raw material containing fine iron ore,
The sintered blending raw material is 5 to 50 mass% pellet feed or fine iron ore that is tailing ore, fine iron ore that is sinter feed, and other raw material powder, miscellaneous raw material powder, and solid fuel powder. Use a sintered compounding material containing one or more types, perform a uniform dispersion process on the fine iron ore and moisture using a high-speed stirrer, and then stir and mix using at least one of a drum mixer and a pan-type pelletizer A method for producing a granulating raw material for sintering, characterized by performing granulation. When the moisture content of the above-mentioned sintered blending material is small, the above-mentioned uniform dispersion treatment is performed by spraying water within a range not exceeding the appropriate moisture value, while the moisture content of the sintered blending material is close to the appropriate moisture value. 2. The method for producing a granulated raw material for sintering according to claim 1, wherein in some cases, the treatment is performed without watering. The pellet feed is fine iron ore with an average particle size of 40 μm to 100 μm, the tailing ore is a residue of fine iron ore with an average particle size of 10 μm or less, and the sinter feed is The method for producing a granulated raw material for sintering according to claim 1 or 2, wherein the average particle size is fine iron ore having a size of 1000 µm or more. The granulated raw material for sintering according to any one of claims 1 to 3, wherein the high-speed stirrer is an Eirich mixer for crushing having a function of crushing the raw material and coarse grains that have grown. Production method. The method for producing a granulated raw material for sintering according to any one of claims 1 to 4, wherein the high-speed stirrer is installed before the drum mixer or after the drum mixer and before the pan-type pelletizer. . The granulation for sintering according to claim 4, wherein the crushing Eirich mixer has a stirring blade rotating at a high speed at a position eccentric in a radial direction with respect to a rotation center of the mixing pan. Raw material manufacturing method. The method for producing a granulation raw material for sintering according to claim 6, wherein the rotation speed of the stirring blade is about 100 to 500 rpm. The method for producing a granulated raw material for sintering according to claim 1, wherein the auxiliary raw material powder is at least one selected from limestone, dolomite, silica stone, and serpentine. 2. The method for producing a granulated raw material for sintering according to claim 1, wherein the miscellaneous raw material powder is at least one selected from dust, scale, and return. The method for producing a granulated raw material for sintering according to claim 1, wherein the solid fuel powder is coke.

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