TWI509081B - Method for producing granulation material for sintering - Google Patents

Description

Method for producing granulated raw material for sintering

The present invention relates to a method for producing a granulated raw material for sintering used in a Dwight Lloyd (DL) type sintering machine.

The sinter is produced by mixing and granulating by adding water to the raw material for sintering, and the obtained granulated raw material is charged into a sintering machine for calcination, and the sintered raw material is iron powder of a plurality of varieties. In the ore (generally referred to as a sinter feed of about 125 μm to 1000 μm), an appropriate amount of auxiliary raw material powder such as limestone, vermiculite or serpentine, powder, scale, ore, etc., coke powder, etc. Made of solid fuel. The sintered raw material generally forms a pseudoparticle by agglomerating at the time of granulation by containing moisture. In addition, when the granulated raw material for sintering, which is subjected to the quasi-particles, is placed on a pallet of a sintering machine, it serves to ensure good ventilation of the sintered raw material-packed layer, thereby facilitating the smooth progress of the sintering reaction.

However, iron ore for sintering has been degraded in recent years due to depletion of high-quality iron ore. That is, the low quality of iron ore tends to increase or pulverize the slag component, and thus the granulation property is lowered due to an increase in the alumina content or an increase in the ratio of the fine powder. On the other hand, as the sinter used in the blast furnace, from the viewpoint of a reduction in the production cost of the molten iron in the blast furnace or a decrease in the amount of generated CO ₂ , a low slag ratio, a high reduction property, and a high strength are sought.

In such an environment surrounding the iron ore for sintering, recently, a technique has been proposed in which a hard-grained micro-iron ore which is used as a particle called a pellet feed is used for manufacture. High quality sinter. For example, in one of the prior art, there is a Hybrid Pelletized Sinter method (hereinafter referred to as "HPS method"). The technique is to granulate a sintered raw material containing a large amount of micro iron powder ore like a pellet supply by using a cylinder mixer and a granulator, thereby producing a low-slag slag ratio and a highly reduced sinter (patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5).

Further, a method of performing humidity conditioning mixing by a high-speed rotary mixer before the granulation step of the sintering raw material powder is also proposed (Patent Document 6); or the micro iron powder ore is previously prepared by a stirring mixer before the granulation step. A method of mixing iron powder (Patent Document 7); a method in which fine powder (particle supply) is mixed in advance by an Eirich mixer, and then granulated by a cylindrical mixer (Patent Document 8).

Prior art literature Patent literature

Patent Document 1: Japanese Patent Special Publication No. 2-4658

Patent Document 2: Japanese Patent Special Publication No. 6-21297

Patent Document 3: Japanese Patent Special Fair 6-21298

Patent Document 4: Japanese Patent Special Fair 6-21299

Patent Document 5: Japanese Patent Special Fair No. 6-60358

Patent Document 6: Japanese Patent Laid-Open No. 60-52534

Patent Document 7: Japanese Patent Laid-Open No. 1-312036

Patent Document 8: Japanese Patent Laid-Open No. Hei 7-331342

However, the sintering preparation raw material containing the micro iron powder ore, in particular, the fine iron powder ore, and the ultrafine iron powder ore, is prepared by using the HPS method described in Patent Documents 1 to 5; In the method of granulation or the mixing treatment previously performed by the high-speed agitator described in Patent Document 6 to Patent Document 8, there are the following problems. The problem is that, as shown in Figure 1, not only fine particles (less than 0.5 mm) are produced and many coarse (more than 10 mm) quasi-particles are produced. The reason is that if the micro iron powder ore like the pellet supply has the same wettability, the finer the fine particles, the larger the specific surface area, and thus the water is easily absorbed, and the powder tends to retain a large amount of water, so that each micro iron powder Ore is easy to absorb water preferentially. As a result, it is easy to generate coarse quasiparticles in which the fine powders are only aggregated, or the fine particles adhere to the periphery of the core particles. Further, in these methods, there is also a problem of adhering the powder, or a poor dispersion of fine powder or moisture, and a problem of lowering the operation rate of the apparatus.

This aspect can be understood from the following experiments conducted by the inventors and the like.

First, in this experiment, it is difficult to granulate micro-iron ore containing particles such as pellets. The raw material of the stone (vanadium content: 40% by mass) was granulated, and at this time, the particle size distribution of the produced granulated particles (quasi-particles) and the particle size distribution of the pellets were measured. The results are shown in Fig. 2 (a) and Fig. 2 (b). First, as shown in Fig. 2(a), the proportion of coarse particles (more than 8 mm) is increased as compared with those who do not contain the particles. Its weight ratio is about 75% by mass. Further, the particle size distribution of the particle feed in the produced quasiparticles (Fig. 2(b)) shows the same tendency as the particle size distribution of the granulated particles (Fig. 2(a)). That is, it is understood that the proportion of the particles fed in the coarse particles is as high as about 80% by mass, and most of the particles are supplied in the coarse particles. Therefore, it is understood that the so-called coarse quasiparticles are formed by agglomerating the particle feeds together. Further, it is understood that the quasi-particles belonging to the coarse-grained region have a high moisture content (Fig. 2(b)). Therefore, the moisture is preferentially absorbed by the particulate feed, so that the particulate feeds are agglomerated with each other to form coarse quasiparticles, and as a result, the coarse quasiparticles absorb a large amount of moisture.

When the raw material of the fine iron ore containing such a large amount of the particulate material or the like is granulated, the particle size does not coincide with each other, and the fine powders are only aggregated with each other, so that the bonding strength is easily formed. The coarse quasiparticles. Therefore, when such quasiparticles are placed on a pallet of a sintering machine and deposited, as shown in Fig. 3 (a), the sintered raw material charging layer has a compact packing structure, and the bulk density is increased. Further, when such coarse quasiparticles are deposited on a pallet of a sintering machine at a fixed layer thickness, the quasiparticles are easily broken when a load (compression force) is applied, and thus the voids are reduced by powdering, and further This causes deterioration of the air permeability and becomes a factor that hinders the operation of the sintering machine. As a result, there is a prolonged sintering time or a sinter The yield is reduced and the productivity is reduced. Further, it is necessary to increase the amount of quicklime used as a binder for granulation, thereby causing an increase in the manufacturing cost of the sinter, or when a solid fuel such as coke powder is coated in a subsequent step, causing coke powder or the like as a whole sintering raw material. The occurrence of the state is uneven. As a result, combustion or poor heat is caused to lower the calcination rate.

An object of the present invention is to provide a method for preventing coarse granulated particles having inconsistent particle diameters and weak bonding strength at the time of granulation in the case where micro iron ore is used as a raw material for sinter production ( Quasi-particles) to create appropriate quasi-particles.

In other words, the present invention provides a method for producing a granulated raw material for sintering, which comprises a micro-iron powder ore and a fine particle which are firmly aggregated, or a micro-iron ore or the like which adheres to the periphery of the core particle. The quasi-particles have a relatively uniform particle size and a small particle size distribution. The granulated raw material for sintering obtained by the method can reduce the density of the sintered raw material-packed layer formed on the pallet or accompanying the air permeability when it is charged to the pallet of the sintering machine. The shortening of the increased calcination time is further effective for improving the productivity of high-quality sintering.

Further, the present invention produces a sintered ore by using such a granulated raw material for sintering, and improves the strength of the sintered ore by improving the combustion efficiency or the conditions for forming the melt, whereby the production cost of the molten iron can be lowered or derived from The amount of CO ₂ produced in the blast furnace is reduced.

The present invention is as follows as described above: not only as an existing ordinary The iron ore (sintered material) of the sintered raw material (average particle diameter: 50% of the particle diameter of about 1000 μm or more in terms of cumulative frequency distribution) is used as one of the raw materials for sintering, and the average particle diameter is also 40 μm. A micro iron powder ore (particle feed) of about 100 μm or an ultrafine iron ore (tailing) showing a particle size distribution of 10 μm or less is used as one of sintering raw materials. In addition, FIG. 4 is a comparative graph of the average particle diameter of the various iron ore fines.

As described above, for the pulverized raw material containing the micro-iron powder ore (average particle diameter: 100 μm or less) which is difficult to granulate as a pellet, when granulating, powder or fine powder, ultrafine powder The water is preferentially aggregated with each other via moisture, and coarse coarse particles having weak bonding strength are easily formed. Further, the quasiparticles mostly have a large particle size distribution (a state in which the difference in particle diameters largely differs), and when the sintering machine is operated, the sintered raw material is loaded (filled) on the pallet as shown in Fig. 3(a). Among the particles in the charged layer of the sintered raw material, the coarse particles and the fine particles are closely packed or irregularly filled to deteriorate the air permeability.

Therefore, the present invention has developed a method of pre-mixing a high-speed mixer using a stirring function to prevent fine powder or ultrafine iron ore before the granulation step of a cylinder mixer and/or a disk granulator. The preferential aggregation of each other achieves uniform dispersion of the micro iron powder ore and moisture, and finally prevents the production of coarse quasiparticles with weak bonding strength, thereby producing a quasi-uniform particle size, a small particle size distribution, and a strong bonding strength. particle.

In other words, the present invention relates to a method for producing a granulated raw material for sintering, which comprises producing a granulated raw material for sintering from a sintered raw material containing fine iron ore ore. The method for producing a granulated raw material is characterized in that the following sintering raw material is used as the sintering raw material, that is, 5% by mass to 50% by mass of micro iron powder ore as a pellet supply or tailings, as sintering Any one or more of the iron ore of the material, the auxiliary raw material powder, the miscellaneous raw material powder, and the solid fuel powder, after uniformly dispersing the fine iron powder ore and the water by using the high-speed mixer At least one of a cylinder mixer and a disk granulator is stirred and mixed to be granulated. According to this method, as shown in FIG. 3(b), by filling the granulated particles of uniform size, the state in which the voids are maintained can be maintained, and it is advantageous to ensure the air permeability.

Further, as a more preferable means for solving the present invention, it is considered that the above-described means for uniformly dispersing the moisture is a treatment in which the amount of moisture in the sintering preparation raw material is small, not exceeding Water is sprinkled within a range of appropriate moisture values. On the other hand, when the moisture of the sintered blending raw material is water close to an appropriate moisture value, watering is not performed; (2) the pellet feeding is average a fine iron ore fine ore having a particle diameter of 40 μm to 100 μm, wherein the tailings is a residue of micro iron ore fine ore having an average particle diameter of 10 μm or less, and the sintered material is iron ore having a size of an average particle diameter of 1000 μm or more; (3) The high-speed agitator is a crushing Ehrlich mixer having a function of crushing raw materials and coarse particles grown; (4) the high-speed agitator is disposed in front of the cylinder mixer or after the cylinder mixer And before the disc granulator; (5) the crushing Ehrlich mixer is at the center of rotation relative to the mixing disc (6) The number of revolutions of the stirring blade is set to be about 100 rpm to 500 rpm; (7) the auxiliary raw material powder is selected from the group consisting of limestone, dolomite, and vermiculite. And (8) the mixed raw material powder is any one or more selected from the group consisting of powder, scale and returning; (9) the solid fuel powder is a coke breeze.

(1) According to the present invention, it is possible to use a large amount of micro-iron powder ore which is difficult to granulate, such as a pellet supply or tailings, as an iron ore for sintering a raw material, and it is advantageous to produce a uniform particle size, a small particle size distribution and a high particle size distribution. A granulated raw material for strength sintering.

(2) Further, according to the present invention, it is possible to effectively achieve uniform dispersion of the fine iron ore fines or moisture during the stirring and mixing of the sintered raw materials, thereby reducing the amount of the binder used in the granulation.

(3) For the granulated raw material for sintering produced by the present invention, when it is placed on a pallet deposited on a DL sintering machine, the sintering raw material can be charged into the layer when the granulated raw material for sintering is charged. The decrease in density can further shorten the calcination time and improve the productivity of the sintering accompanying the improvement in the air permeability.

1‧‧‧Cylinder mixer

2‧‧‧Disc granulator

3‧‧‧Cylinder mixer for external use of coke powder/auxiliary material

4‧‧‧High speed mixer

5‧‧‧Mixed disc

6‧‧‧Agitating blades

7‧‧‧Scraper

Fig. 1 is a graph comparing the particle size distribution of quasiparticles in the presence or absence of micro iron ore.

2(a) and 2(b) show the particle diameters of the quasiparticles (granulated particles). A plot of the distribution of particle feed and the dispersion of moisture.

Fig. 3 (a) and Fig. 3 (b) are comparison diagrams of Fig. 3 (a) of the conventional granulated particle deposition layer and Fig. 3 (b) of the granulated particle deposition layer of the present invention.

Fig. 4 is a graph comparing the average particle diameters of iron powder ore, micro iron powder ore, and ultrafine iron powder ore.

5(a) to 5(e) are comparison views of the granulation raw material manufacturing equipment for sintering which changes the installation position of the high-speed mixer.

6(a) and 6(b) are graphs showing the relationship between the stirring crushing position of the high-speed agitator and the average diameter of the granulated particles and the air permeability in the granulation test.

7( a ) to 7 ( c ) are graphs showing the relationship between the stirring crushing position of the high-speed agitator, the yield of the finished product, the firing time, and the productivity in the granulation test.

8(a) and 8(b) are schematic views showing an example of a stirring blade arrangement structure of a high-speed agitator (Ehrlich mixer).

3(a) and 3(b) are schematic diagrams showing structural features of a quasi-particle-laden layer as a granulated raw material for sintering. The quasi-particle of the prior type shown in Fig. 3(a) is obtained by the method shown in Fig. 5(a). That is, the conventional manufacturing process for granulating raw materials for sintering is a method in which iron ore fine powder or secondary raw material powder cut out from a mixing tank is first mixed by a cylinder mixer 1, and then the mixed raw materials are sent. The granulation treatment is carried out in a granulator such as a disk granulator 2. In addition, in the mixing step and the granulation step, water is added in an amount of about 1% by mass to about 2% by mass, and humidification is adjusted so as to become a predetermined granulated water, thereby producing a product. Quasi-particles needed. In addition, the 3 shown in the figure is a cylindrical mixer for exterior packaging containing external coke powder and an auxiliary material.

On the other hand, in the present invention having the structure of the quasiparticles shown in Fig. 3 (b), the conventional granulation raw material for sintering is used instead of the mixing step of the cylindrical mixer and the granulation step of the disk granulator. Manufacturing process, and as shown in FIG. 5(b), before the mixing step of the cylinder mixer 1, the following steps are added, that is, the sintering preparation material containing the micro iron powder ore is firstly used as an Ehrlich mixer The high-speed agitator 4 performs uniform dispersion (diffusion) of the micro-iron powder ore and uniform dispersion treatment of moisture. Further, the present invention is a method in which, as shown in Fig. 5(c), after the mixing step of the cylinder mixer 1 and before the granulator 2, the following steps are added, that is, using an Ehrlich mixer The high-speed agitator 4 performs uniform dispersion (diffusion) of the fine iron ore and uniform dispersion treatment of moisture.

Thus, it is known that in the case of preparing a raw material for sintering, the sintered raw material contains, in addition to the usual iron ore as a frit, a plurality of such fine iron ore as a pellet feed or tailings (below) , the tailings containing ultrafine powder is called micro iron powder ore. When it is unloaded from the ship, discharged to the raw material site, mixed with several kinds of powder and micro iron powder ore, ore oredding, it is not allowed. It is avoided to form aggregates or coarse quasi-particles in which the fine powder raw materials are not too concentrated with each other. When this state is maintained (without any treatment), the mixture is supplied to the cylinder mixer for mixing treatment, or the granulation treatment is continued by the granulator 2, and coarse aggregated particles having weak bonding strength are inevitably generated. Or a quasiparticle, which becomes a granulation raw material for sintering which has a particle diameter inconsistent and a large particle size distribution range.

Therefore, in the present invention, the sintered mixed raw material containing the fine iron ore fine ore of 5% by mass or more and 50% by mass or less is stirred and mixed in the cylindrical mixer 1 as shown in Fig. 5 (b). Before the treatment, or as shown in Fig. 5(c), before the granulation treatment of the disc granulator 2 after the cylinder mixer 1, by the high-speed mixer (Ehrlich mixer 4), especially for the micro-iron The fine ore is appropriately supplied with an appropriate amount of water to achieve uniform dispersion treatment of both. The reason for this is derived from the results of the granulation test in the laboratory described below. In other words, it is considered that it is effective to uniformly disperse the sintered raw material at least before the first stage of the final granulation treatment, and to uniformly disperse it according to an appropriate amount of water corresponding to the particle diameter and the initial moisture. For example, in order to prepare an appropriate moisture value (for example, about 7% by mass) suitable for high-speed stirring of a high-speed mixer in accordance with the initial moisture content (about 0.1% by mass to 10% by mass) of the raw material for sintering, it is necessary to prepare the sintering in the sintering. When the initial moisture content of the raw material is small (0.1% by mass to 5.5% by mass), water is sprinkled during stirring. On the other hand, it is preferable to stop watering when the initial moisture of the sintered raw material approaches an appropriate moisture value (for example, 6.5% by mass).

In order to achieve uniform dispersion of raw materials, especially micro iron ore, and uniform dispersion of particle diameters in consideration of the addition of moisture or the like, the flow chart shown in FIG. 5 is preferably used at which point in time. The treatment is carried out in the following five cases: (a) the existing method (no Ehrlich mixer), (b) the method of placing the Ehrlich mixer in front of the cylinder mixer, and (c) the Ehrlich mixer a method of installing after the cylinder mixer (before the granulator), (d) a method of installing the Ehrlich mixer in the granulator, and (e) placing the Ehrlich mixer in the granulator, and A method of sieving and crushing only the coarse particles after the treatment with the Ehrlich mixer. In addition, the sintering mix used The raw materials were a sinter: 80% by mass, a pellet supply: 16% by mass, a tailings: 4% by mass, and an Ehrlich mixer was used as a high-speed mixer. The results are shown in Fig. 6 (a) and Fig. 6 (b).

Fig. 6 (a) and Fig. 6 (b) show the influence on the average diameter and the air permeability of the granulated particles due to the difference in the position of the Eigen mixer. According to this, in the case (b) before the Ehrlich mixer is installed in the cylinder mixer, the coarse particles (particles in which the fine powders are aggregated) are crushed and diffused, and the water is uniformly dispersed as a whole, so that the particles are averaged. The diameter is about 4.3 mm and becomes an appropriate particle. On the other hand, in the case (c) in which the Ehrlich mixer is installed in a cylinder mixer (before the disc granulator), the granulation is caused by crushing after granulation, but the average is performed. The particle size was slightly lowered to 4.25 mm. Further, regarding the air permeability index (JPU), the case (b) in which the Ehrlich mixer was placed before the cylinder mixer was a good result. Further, in the case (d) after the Alpha mixer was installed in the granulator, the air permeability index was slightly lowered as compared with the case (b), and the Ehrlich mixer was placed in the granulator and only crushed. The case of the coarse particles (e) shows the same degree of characteristics as the case (b).

Next, when the granulated raw material for sintering produced by the above-described four cases (b to e) in which the position of the Elevator of the high-speed mixer is changed is applied to the DL sintering machine to produce the sintered ore. The yield, sintering time, and productivity of each item were evaluated. The results are shown in Fig. 7 (a) to Fig. 7 (c).

As shown in Fig. 7 (a) to Fig. 7 (c), in the case (b) before the Alpha mixer is disposed in the cylinder mixer, the air permeability is improved and the sintering reaction proceeds uniformly, so that the calcination time is shortened. And productivity is improved. On the other hand, mixing Ehrlich In the case (c) after the machine is installed in the cylinder mixer, the sintered granulated raw material obtained in this case is used to produce sintered ore, and as a result, the average particle diameter of the granulated particles is reduced as compared with the case (b). However, the particle size distribution is improved, so that the air permeability is improved and the sintering reaction proceeds uniformly, whereby the calcination time is shortened and the productivity is improved. In the case (d) after the Ehrlich mixer is installed in the granulator, the average particle diameter of the granulated particles is the same as in the case (b), but the particle diameters are not uniform, the air permeability is insufficient, and the sintering reaction is uneven. Thereby, the calcination time is prolonged and the productivity is lowered.

Regarding the above-mentioned experiment, it is known that the position of the high-speed mixer (Ehrlich Mixer) is set before the cylinder mixer or before the disc granulator after the cylinder mixer. Good results are obtained, and these methods are employed as the method of the present invention.

In addition, an Ehrlich mixer was used as a high speed mixer in the experiment. The Ehrlich mixer is a well-known high-speed stirring granulator, and is a device that combines the function of crushing-diffusion of particles, particularly coarse particles, with aggregation and growth of particles that are crosslinked by liquid. Granulation function.

In the present invention, an apparatus configuration that further enhances the high-speed stirring function of the Alpha mixer is used. In other words, the high-speed agitator suitable for the present invention has a structure in which it is slightly eccentric in the radial direction with respect to the center of rotation of the mixing disc 5 (the coarse quasi-particles tend to stay and are eccentric to the clockwise side). Positioning, a plurality of agitating blades 6 are radially arranged and offset in the up-and-down direction as shown in FIG. 8, thereby preventing co-rotation of the agitating blade and the raw material and efficiently mixing and mixing the raw materials. It is better to strengthen the sintering than to strengthen the granulation. The crushing-diffusion effect of the material and the generated particles. By adopting such a configuration, uniform dispersion (diffusion) of the micro iron ore itself is achieved, and uniform dispersion and coarse particles are realized by effective supply of added moisture (sprinkling) corresponding to the initial moisture and particle size distribution of the raw material. Crushed, granulated.

The speed of the agitating blade can be freely changed from a high speed at which high shear force is exerted to a low speed at which granulation is achieved by slow agitation, and the present invention is particularly characterized by the following device configuration, that is, agitation The speed is set to high speed, and the crushing of the raw material is promoted, and the strong stirring (diffusion) of the micro iron powder ore corresponds to the proper supply of the water having the particle diameter and the initial moisture value, that is, the uniform diffusion of the water, the dispersion and the mixing, the local particle. Growth (granulation). Further, it is considered that when the stirring blade is operated at the medium speed to the low speed side, it contributes to the growth of the granules and the growth of the granules, and the crushing action of the raw materials is slightly lost.

However, in the above-described prior art (Patent Documents 6 to 8), even when a high-speed agitator is used, the humidity is adjusted without considering the appropriate moisture value at the time of high-speed stirring, so that it is charged to the mixer. The moisture of the raw material increases, the adhesion to the inside of the mixer and the blade increases, and the load current value increases. As a result, there is a problem that the shearing force of the agitator is lowered, resulting in a decrease in the crushing force of the raw material and causing deterioration of the particle size distribution.

In this regard, in the present invention, the initial moisture value of the sintering preparation raw material charged to the high-speed agitator is monitored, and can be maintained at a level lower than the appropriate granulated moisture value (for example, about 7 mass%). In the case where the moisture of the raw material is close to the dryness, for example, in the high-speed mixer, water is sprinkled within a range not exceeding the appropriate moisture value, and when the initial moisture value of the raw material is close to the appropriate moisture, the method is stopped. Sprinkling water in a high speed mixer.

As a result, the adhesion of the raw materials in the high-speed agitator can be effectively suppressed with respect to the conventional method, and an excellent stirring effect can be exhibited. That is, the granulation operation is added after sufficiently reducing the moisture in the raw material, particularly the moisture on the side of the coarse particles, whereby the coarse particles in the granulated particles can be effectively reduced. Therefore, in the present invention, it is suggested that in order to improve the sintering productivity, it is important to appropriately control the particle size distribution of the granulated particles. That is, the appropriate particle size distribution is a distribution in which the ratio of the coarse particles and the ungranulated powder is low.

In order to achieve the strengthening of the crushing function or the uniform dispersion of the high-speed stirring which is peculiar to the present invention, it is recommended that the number of revolutions of the stirring blade is from 100 rpm to 500 rpm, preferably from 150 rpm to 350 rpm. This is because the stirring effect or the like cannot be obtained at a slow speed of less than 100 rpm, which is not preferable. In this case, the rotation speed of the mixing disc 5 as the main body is always operated at a constant speed of about 15 rpm, and the number of the stirring blades 6 can be applied to about 8 to 32 pieces. By.

Further, the mixing disc 5 is a rotary disk-shaped container that rotates the entire raw material, whereby all the raw materials in the mixer can be kept flowing. Further, a scraper 7 is usually provided in the high speed mixer. The scraper blade 7 is positioned above the mixing disc 5, and serves to peel off the material to be stayed in the vicinity of the inner wall or the bottom surface of the mixing disc 5, and to continuously feed the raw material to the stirring blade 6. In particular, the material to be retained at the bottom is peeled off by a bottom blade (not shown) attached to the lowermost end of the stirring blade, but it is preferably used together with the blade 7.

On the other hand, when the number of revolutions of the stirring blade was 80 rpm and the number of stirring blades was eight, it was observed that a large number of coarse quasiparticles were produced, and the average diameter of the quasiparticles was as large as Around 4.5 mm, the weight ratio of quasiparticles is about 13%, which is no different from the existing methods.

When a sintered ore is produced by using the granulated raw material for sintering produced by the method of the present invention, an effect of improving the yield of sintered ore or the strength of sintered ore can be expected. This is because, in the conventional method, the quasiparticles having uneven particle size are covered with the coke powder, so that the combustion or the heat is uneven, and the yield is lowered. However, in the case of the granulated raw material for sintering produced by applying the present invention, It becomes a relatively uniform particle size, and thus the state of occurrence of the coke powder is also optimized. Further, in the case where the external granulation of the coke powder is not carried out, uniform mixing before granulation is required in order to achieve uniform mixing of the coke powder or the limestone, but in the case of the present invention, the burden can be alleviated.

[Examples]

This embodiment is implemented using a method in accordance with the apparatus flow shown in Fig. 5(b). The sintered raw material used in this example is mainly composed of 50% by mass of iron ore (average diameter: 3.8 mm) produced in Australia and 50% by mass of iron ore (average diameter: 2.7 mm) produced in South America. Further, in the case of blending the fine iron ore fines as the pellet supply, especially when the blending ratio is 20% by mass or more, it is dealt with by not changing the blending ratio of the Australian iron ore and the South American iron ore (1). :1), transfer these kinds of ore. Further, as the micro iron ore, the tailings (residues generated during the process of producing the pellets) are also used as a part of the micro iron powder ore. Further, the sintering preparation raw material is based on a basicity of 2.0.

The high-speed agitator is installed at a position before the cylinder mixer or after the cylinder mixer and before the granulator, and the operation is changed according to the sintering raw material and the operating conditions, thereby enhancing external monitoring. In particular, attention is paid to controlling the rotational speed of the agitating blades of the high-speed agitator, and also adjusting the gap with the inner bottom surface of the mixing disc, thereby specifically targeting the uniform dispersion of the micro-iron ore or quasi-particles for stirring. Running. Therefore, in the present embodiment, a thickness measuring device such as a laser displacement meter or the like is also used. Further, by adjusting the rotation speed of the stirring blade, the size of the agitated micro iron ore or quasiparticles, that is, the degree of crushing is adjusted.

An Ehrlich mixer was used as a high speed mixer. The diameter of the mixing disc of the used Ehrlich mixer was 0.75 m, the number of revolutions (counterclockwise) was set to 15 rpm, and the stirring blade (eccentric distance from the center of the disc: 115 mm) was used: number of revolutions: 250 rpm, number of stirring blades: 8. In order to prevent the co-rotation of the raw materials, the rotation direction of the stirring blade is set to be opposite to the rotation direction of the mixing disk. Further, in order to efficiently crush coarse particles having a particle diameter of 8 mm or more, the gap between the tip end portion of the stirring blade and the inner bottom surface of the mixing disk is based on about 8 mm. As a result, the coarse quasi-particles having a particle diameter of 8 mm or more were surely crushed. The obtained granulated quasiparticles had an average diameter of 4.3 mm, thereby obtaining a desired granulated raw material for sintering.

[Industrial availability]

The manufacturing technique of the present invention can be applied not only to the production of granulated raw materials for sintering but also to the manufacturing technology of block mineralization for blast furnaces.

Claims (7)

A method for producing a granulated raw material for sintering, which comprises producing a granulated raw material for sintering from a sintered raw material containing fine iron ore ore, wherein the method for producing a granulated raw material for sintering is characterized in that the following sintered raw material is used as a raw material The sintered raw material, that is, contains 5 to 50% by mass of micro iron powder ore as a pellet supply or tailings, iron ore as a sintering material, and auxiliary raw material powder, miscellaneous raw material powder and solid fuel powder. Any one or more of the above-mentioned sintering preparation raw materials, after uniformly dispersing the fine iron powder ore and moisture using a high-speed mixer, using at least one of a cylinder mixer and a disc granulator The granulation is carried out by stirring and mixing, and the high-speed agitator includes a crushing Ehrlich mixer having a function of crushing the raw material and the coarse particles of the grain growth, the crushing Ehrlich mixer being in a state of being opposed to the mixing disc The rotation center is formed by arranging a stirring blade that rotates at a high speed in a position eccentric in the radial direction, and the number of rotations of the agitation blade is set to about 100 rpm to 500 rpm. The method for producing a granulated raw material for sintering according to the first aspect of the invention, wherein the uniform dispersion treatment of moisture is a treatment in which the amount of water in the sintering preparation raw material is small, not exceeding Water is sprinkled in a range of an appropriate moisture value. On the other hand, when the moisture of the sintered raw material is water close to an appropriate moisture value, watering is not performed. The method for producing a granulated raw material for sintering according to the first or second aspect of the invention, wherein The pellets are micro iron powder ore having an average particle diameter of 40 μm to 100 μm, and the tailings are residues of micro iron powder ore having an average particle diameter of 10 μm or less, and the sintered material has an average particle diameter of 1000 μm or more. The size of the iron ore. The method for producing a granulation raw material for sintering according to the first or second aspect of the invention, wherein the high speed agitator is disposed before the cylinder mixer or after the cylinder mixer and the circle Before the disc granulator. The method for producing a granulated raw material for sintering according to the first aspect of the invention, wherein the auxiliary raw material powder is at least one selected from the group consisting of limestone, dolomite, vermiculite, and serpentine. The method for producing a granulated raw material for sintering according to the first aspect of the invention, wherein the raw material powder is at least one selected from the group consisting of powder, scale and return. The method for producing a granulated raw material for sintering according to the first aspect of the invention, wherein the solid fuel powder is a coke breeze.