JP4378943B2 - Method and apparatus for pseudo-sintering raw material for sintering - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pretreatment of a sintering raw material for producing a sintered ore charged in a blast furnace, and more particularly to a method and apparatus for forming a pseudo raw material of a sintering raw material using a rotary mixer.
[0002]
[Prior art]
Sinter is used as a raw material for iron making charged in the blast furnace. This sintered ore is generally made into pseudo particles by mixing and granulating iron-containing raw materials such as iron ore powder, iron-containing dust, sludge, etc., binders such as quick lime, limestone and slaked lime, and fuel and other auxiliary materials such as powdered coke. After that, it is manufactured by firing with a sintering machine. Usually, the lower suction type is used for the sintering machine, and the air necessary for sintering is sucked from the lower side of the sintering raw material and the fuel is burned from the upper side to the lower side of the sintering raw material. As a result, the sintered raw material is fired. For this reason, the sintering raw material has sufficient air permeability, and it is necessary that the powder coke as a fuel burns quickly and the sintering proceeds smoothly. Moreover, it is necessary that the sintered ore after firing has a predetermined strength.
[0003]
For this reason, as a pretreatment of the sintering raw material, pseudo-particle formation using a rotary mixer (also referred to as a drum mixer) is widely performed, and a part of the auxiliary raw material is added to ensure the above-mentioned purpose. For example, Patent Document 1 proposes a granulation method in which so-called three-layer pseudo particles are obtained by adding powder coke and limestone. The purpose of adding the powder coke and / or limestone is to attach the auxiliary material to be added to the surface of the pseudo particle. As a result, a pseudo-particle surface layer is formed on the coarse particles as the first layer and the outer periphery of the fine particles as a fine second layer, and a third layer rich in powder coke and / or limestone is formed. When the sintered ore is produced from the raw material, the combustibility of the powder coke is increased, and the production efficiency of the sintered ore can be improved.
[0004]
In Japanese Patent Application Laid-Open No. 2004-228561, supplementary raw materials for such a purpose are performed by inserting a belt conveyor into a rotary mixer and adding the raw materials. In addition, as another additional means, Patent Document 2 discloses that injection addition is performed from the discharge side of the rotary mixer using an air flow in the region from the intermediate portion in the raw material flow direction of the rotary mixer to the discharge side (discharge side). The method to do is mentioned.
[0005]
[Patent Document 1]
JP 2002-285250 A [Patent Document 2]
Japanese Patent Laid-Open No. 58-189335 [0006]
[Problems to be solved by the invention]
However, the additional method described in Patent Document 1, particularly the method using a belt conveyor, has the following problems. That is, deposits adhering to the inner wall during the granulation process in the rotary mixer fall onto the belt conveyor and adhere to and accumulate on the belt conveyor. A great deal of labor is required to remove this adhesion and deposit. Also, sometimes the drive part of the belt conveyor is damaged, causing interruption of operation. Further, when the deposit on the belt conveyor becomes excessive, the deposit contacts the rotary mixer inner wall, or the belt conveyor is bent by the load of the deposit and contacts the rotary mixer inner wall. Such contact between the inner wall of the rotary mixer and the deposit causes great damage to the inner wall of the rotary mixer, which causes the operation to be stopped and causes a serious safety problem.
[0007]
In addition, in the method according to Patent Document 2, the equipment cost for attaching an airflow generation device for additional equipment, an additional additive transport device, an injection device, and the like becomes excessive. Moreover, in the part in the rotary mixer of the injection device, the fall of deposits from the inner wall of the rotary mixer, or dust adheres to the part of the apparatus and smooth operation is hindered. Furthermore, in this method, since the supplementary auxiliary material is injected and added by the air flow toward the charging side of the rotary mixer, the additional auxiliary material is widely scattered in the rotary mixer and scattered to the charging side of the rotary mixer. Since the auxiliary material dispersed to the charging side is taken into the sintered raw material in the granulation process by the rotary mixer, the aim of attaching the additional auxiliary material to the surface of the pseudo particle cannot be realized.
[0008]
The present invention has been made to solve the above-mentioned problems, and a method for producing pseudo particles having a layer rich in powdered coke suitable for a sintering raw material as an outermost layer and a method for realizing the method. An object of the present invention is to propose a quasi-particle generator.
[0009]
[Means for solving the problems]
The method for pseudo-sintering a raw material for sintering according to the present invention uses an additional conveyor installed on the discharge port side of the rotary mixer when charging the iron-containing raw material into a rotary mixer to make pseudo particles. The discharge end of the loading conveyor is separated and brought close to the rear of the rotary mixer discharge port, and the supplementary auxiliary material is projected from the discharge end of the rotary mixer into the rear end portion of the rotary mixer. .
[0010]
In this pseudo-particle formation, it is preferable that the additional range of the additional auxiliary material is in a range of 1/4 to 1/12 from the discharge port with respect to the entire length of the rotary mixer in the rear end portion of the rotary mixer. is there. Further, it is preferable to add powdered coke to the above range of the rotary mixer, and optionally powdered coke and quicklime or limestone.
[0011]
In the apparatus for carrying out the pseudo-particle formation method, the additional conveyor is disposed on the discharge port side of the rotary mixer , and the discharge end thereof is disposed so as to be separated and close to the rear of the discharge port of the rotary mixer. In addition, it is preferable to use the additional conveyor that can adjust the projection distance by adjusting the initial projection speed and / or elevation angle of the additional auxiliary material .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing an outline of an iron-containing raw material pseudo-particle forming apparatus according to an embodiment of the present invention. The apparatus includes a raw material conveyor 1 for conveying the iron-containing raw material 5, a chute 2 for cutting the conveyed iron-containing raw material 5 into a rotary mixer 3, and a rotary mixer for converting the iron-containing raw material 5 into pseudo particles while rolling and transferring the iron-containing raw material 5. 3, an additional conveyor 10 that projects the auxiliary auxiliary material 11 in the middle of pseudo-particle formation of the iron-containing raw material 5, and an exhausting conveyor 20 that conveys the sintered raw material 21 after pseudo-particle formation to a sintering machine, Is provided. The additional conveyor 10 and the discharge conveyor 20 are provided close to the rotary mixer discharge port 4.
[0013]
When a predetermined iron-containing raw material 5 is cut out by the chute 2 and charged into the rotary mixer 3, the raw material rolls in the right direction in FIG. Pseudo-particle formation progresses by attaching. Then, the iron-containing material amount 5 that has been pseudo-granulated is discharged from the discharge port 4 of the rotary mixer by the discharge conveyor 20 and the granulation process is completed.
[0014]
In the granulation step, the supplementary auxiliary material is projected onto the iron-containing material that is being pseudo-granulated at a position that is almost the final step of pseudo-granulation, that is, at the rear end of the rotary mixer. Any additional material can be selected. For example, when powder coke or a mixture of powder coke and quicklime or limestone is used as a supplementary auxiliary material, a sintered material having air permeability and excellent combustion characteristics can be obtained. That is, by this additional operation, an outer shell rich in powder coke and lime is formed in the outer layer portion of the pseudo particle. The existence of the outer shell leads to stabilization of the shape and improvement of strength of the pseudo particles.
[0015]
As described above, in order to obtain a sintered raw material suitable for the sintered ore, the auxiliary raw material mounting position in the rotary mixer is important. If the mounting position is at the front end in the rotary mixer, the pseudo particles serving as nuclei are not sufficiently formed and grown, so that the additional components are taken into the pseudo particles. On the other hand, even if the repositioning position is in the middle part, the destruction of the sintering raw material is also progressing at the same time as the granulation action (pseudo-particle formation) of the sintering raw material. The purpose of making pseudo-particles of a three-layer structure in which the auxiliary material is taken in and the outermost layer is rich in powdered coke or the like cannot be achieved. Furthermore, if the rear end portion is too far, the added auxiliary raw material does not uniformly adhere to the outermost layer of the pseudo particles, and may remain in an unattached state, thereby preventing the smooth progress of the sintering. . For this reason, when the raw material reaches the rear end portion of the rotary mixer, especially when it reaches the range of 1/4 to 1/12 from the discharge port 4 with respect to the entire length of the rotary mixer, the additional auxiliary material is additionally mounted. It is good.
[0016]
In order to perform such additional loading, it is possible to throw additional auxiliary raw material from the rear end of the rotary mixer, but as shown in FIG. 1, the discharge of the additional conveyor close to the rotary mixer discharge port is performed. It is preferable to provide an additional conveyor that can project additional components by projecting additional components from the end to a predetermined range in the rotary mixer.
[0017]
FIG. 3 is a schematic diagram of a supplementary auxiliary material projection experiment apparatus, which includes a drive motor M and an inverter control unit INV that controls the rotation speed of the motor. FIG. 4 is a graph showing the extent of the auxiliary auxiliary material projection distance and the degree of dispersion of the auxiliary auxiliary material, using the speed of the belt conveyor and the falling distance from the end of the belt conveyor as parameters. . In this experiment, using the additional materials that are usually used, the height of the belt conveyor end is set at 1.75 m above the ground, and the conveyor speed of the belt conveyor is changed to 60 m / min, 180 m / min, and 300 m / min. It was. The range of the projection distance that includes 90% of the projectile (referred to as the mainstream range) is included in the range of about 300 mm centered on the projection distance represented by the parabolic motion formula of the mass point indicated by the broken line in FIG. It was confirmed that if this device was used, the additional raw materials could be projected almost together without being scattered. The projection distance in the experiment of projecting powder coke and limestone of the particle size and quantity ratio used for the sintering raw material as the additional auxiliary material is almost the same as the calculated value, and it is transferred into the rotary mixer by the additional conveyor. When projecting additional materials, it was found that the projection distance can be estimated by the above parabolic equation. Therefore, using this, the operation parameters such as the initial speed and projection level of the supplementary conveyor are determined, and the rotation speed of the drive motor M is adjusted while checking the projection distance of the supplementary auxiliary material to convey the belt conveyor. If the speed is controlled, the additional position can be adjusted.
[0018]
In addition, although the elevation angle is not given to the belt conveyor in the additional experiment, it is preferable that the additional conveyor 10 has an elevation angle control means so that not only the initial speed but also the elevation angle can be adjusted. Further, depending on the properties of the supplementary auxiliary material, it is preferable to widen the dispersion range of the additional auxiliary material. FIG. 2 shows an example of means for extending the dispersion range of the supplementary auxiliary materials. In the case of FIG. 2 (a), the additional conveyor 10 is installed obliquely with respect to the axial direction of the rotary mixer 3 to widen the dispersion range of the additional auxiliary material. In the case of FIG. 2 (b), the additional conveyor 10 is installed eccentrically from the central axis of the rotary mixer 3 to widen the dispersion range of the additional auxiliary material.
[0019]
According to the above apparatus of the present invention, the equipment cost can be kept low. Moreover, unlike the one by pneumatic transportation, various sizes of powder coke can be added to the same range. Even those having a large particle size or wet and heavy can be added to the target range. Further, since the additional conveyor 10 is outside the rotary mixer 3, there is no problem due to adhering matter, and maintenance is easy.
[0020]
【Example】
6.5t / min of iron-containing raw material consisting of iron ore powder, return mineral, iron-containing dust, sludge and silica sand is cut out from the chute into the rotary mixer, and a 24-m long rotary mixer is rotated at a speed of 3.5 to 4.5 (times / min) The raw material was transferred in the rotary mixer at a speed of 20 m / 300 to 360 s. The additional conveyor 10 touches the rotary mixer discharge port from the center of the discharge port so that the projection position of the additional material is 3 to 3.5 m above the average height of the upper surface of the material in the rotary mixer. It was installed 1-1.5m above. The additional raw materials were projected at a supply rate of 0.6 to 0.9 t / min for limestone and 0.2 to 0.3 t / min for powdered coke. The conveyor speed at this time was 120 to 600 m / min, and the projection range of the supplementary auxiliary material was in the range of 1 to 6 m from the rotary mixer discharge port.
[0021]
The pseudo particles obtained when the projecting range of the supplementary auxiliary material is set to the range of 1 to 6 m from the rotary mixer discharge port have a particle size of 1 to 1.5 mm and the outermost layer is a powder coke-rich outside. It was a shell. When the sintered raw material composed of the pseudo particles was sintered with a Dwytroid type sintering machine, the air permeability and the combustibility during the sintering were good, and the obtained sintered ore had the required strength. It was. However, the pseudo particles obtained when the projecting range of the supplementary auxiliary material is less than 1 m from the rotary mixer discharge port has a particle diameter of 1 to 1.5 mm, but the powder coke to the outermost layer part The sintered ore obtained with a small amount of adhesion and poor air permeability and combustibility during sintering did not have the required strength. On the other hand, the pseudo particles obtained when the projecting range of the supplementary auxiliary material is in a position exceeding 6 m from the rotary mixer discharge port has a particle size of 1.1 to 1.45 mm, and a considerable portion of limestone and powder coke is simulated. The limestone and powder coke that are entrained inside the particles and adhered to the outermost layer of the pseudo particles are relatively small, and the sintered ore obtained with poor air permeability and combustibility during sintering has the required strength. It wasn't.
[0022]
【The invention's effect】
According to the present invention, the equipment cost can be kept low, and a sintered raw material having air permeability and excellent combustibility can be obtained by an apparatus that is easy to maintain.
[Brief description of the drawings]
FIG. 1 is a schematic front view showing a sintering raw material pretreatment apparatus according to the present invention.
FIGS. 2A and 2B are a plan view and a partial cross-sectional view showing an example of means for expanding the dispersion range of the supplementary auxiliary material. FIGS.
FIG. 3 is a schematic view of a supplementary auxiliary material projection experiment apparatus.
FIG. 4 shows the projection distance of the supplementary auxiliary material and the degree of dispersion of the supplementary auxiliary material, using the speed of the belt conveyor and the drop distance from the end of the belt conveyor as parameters, using the experimental apparatus shown in FIG. It is a graph which shows.
[Explanation of symbols]
1: Raw material conveyor
2: Shoot
3: Rotary mixer
4: Exhaust outlet
5: Iron-containing raw materials
10: Additional conveyor
11: Supplementary auxiliary materials
20: Exhaust conveyor
21 ： Sintering raw material

Claims (4)

In charging the iron-containing raw material into the rotary mixer and making it into pseudo particles, the additional conveyor installed on the rotary outlet side of the rotary mixer is used, and the discharge end of the additional conveyor is located behind the rotary mixer outlet A method for forming a sintered raw material into pseudo particles by projecting the auxiliary auxiliary material from the discharge end of the rotary mixer into the rear end portion of the rotary mixer .   The additional range of the additional auxiliary material is a range of 1/4 to 1/12 from the discharge port with respect to the entire length of the rotary mixer in the rear end portion of the rotary mixer. A method for forming a spun raw material into pseudo particles.   The method for forming pseudo-sintered raw materials according to claim 1 or 2, wherein the auxiliary auxiliary material is powder coke, or powder coke and quick lime or limestone. An additional conveyor is disposed on the discharge port side of the rotary mixer, and a discharge end of the additional conveyer is disposed at the rear of the rotary mixer discharge port so as to be able to be separated and approached. An apparatus for quasi-particle formation of a sintered material, wherein the projection distance can be adjusted by adjusting the initial projection speed and / or elevation angle of the material.

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