JP2015117401A - Facility and method for granulating sintering material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a granulation facility and method for a sintering material, capable of obtaining a proper grain size distribution and of easily and effectively maintaining or improving the productivity of a sintered ore even when using a powdery iron ore (fine powdery ore or the like) for the sintering material as a main ingredient.SOLUTION: A granulation facility 10 for a sintering material comprises a pan pelletizer (disc type granulator) 20 for granulating a sintering material 1 into a pellet 2, and an agitator 30 for agitating and crushing the sintering material 1 during granulation or/and the pellet 2 after granulation with the pan pelletizer 20. In the granulation of the sintering material 1 into the pellet 2, agitation blades 33 of the agitator 30 are rotated by a revolution at which the load torque of the agitator 30 becomes maximum.

Description

  The present invention relates to a granulation facility and a granulation method for a sintered raw material, in which a sintered raw material is granulated to obtain a sintered raw material granulated product (pellet).

  Generally, in the iron making process, powdered ore, which is a raw material for sintering, is mixed with limestone powder raw materials and other auxiliary raw materials, and drum mixers (drum type granulators with a cylindrical rotating body) or pan pelletizers (dish-shaped) Disk-type granulator equipped with a rotating body) and granulated while adding water to form a sintered raw material granulated product (pellet), and then sintered with a sintering machine to obtain a sintered ore. Used in blast furnace. This sintered raw material granulated product is obtained by attaching a powder having a diameter of 1 mm or less to a core having a diameter of several millimeters, and is called “pseudo particle”.

  As granulation methods, a raw material mixed with coarse ore and fine ore is added to a drum mixer and granulated while spraying water, and a mixture of coarse ore and fine ore is added to a pan pelletizer. In addition, there is known a method of manufacturing pseudo particles by adding moisture to attach fine powder ore around coarse ore.

  Due to the recent supply of raw materials, the need to use fine ore (average diameter of about 40 to 150 μm) having a smaller particle size than conventional fine ore (average diameter of about 1 to 3 mm) is increasing. In the method, coarse “adhesion particles” with weak strength with fine powders adhering to each other increase, the proportion of pseudo particles decreases, uniform granulated products are not formed, and the productivity of sintered ore cannot be maintained. Yes.

  Therefore, Patent Document 1 proposes a method of producing a pre-granulated product using an Eirich mixer and a pan pelletizer, granulating the remaining raw material with a drum mixer, and introducing the pre-granulated product at the end of the process. Has been.

  Moreover, in patent document 2, in order to improve granulation property, the method of installing a stirring apparatus (stirring blade) in a granulation apparatus and stirring the mixture (sintering raw material) in a bread (raw material tank) is proposed. Has been.

JP 2003-113425 A JP 2002-317228 A

  However, as in Patent Document 1, the method of granulating and mixing a part of the raw material in advance has a problem that the granulation process increases, leading to an increase in equipment costs and operating costs.

  Moreover, in the said patent document 2, it cannot be said that the stirring apparatus is fully used effectively.

  The present invention has been made in view of the above circumstances, and an appropriate particle size distribution is obtained even when powdered iron ore (such as fine powder ore) is used as the main sintering raw material. An object of the present invention is to provide a granulation facility and a granulation method for a sintered raw material that can easily and effectively maintain and improve the productivity of sintered ore.

  The present inventors have intensively studied to solve the above problems. As a result, in the process of granulating a sintered raw material mainly composed of powdered iron ore (fine ore etc.) into a sintered raw material granulated product (pellet) with a disk type granulator or drum type granulator, A stirring and crushing device (stirring blade) is installed inside the mold granulator or drum type granulator, and the sintered raw material during granulation and pellets after granulation are stirred and crushed by the stirring and crushing device (stirring blade). Upon granulation, it was found that there is a correlation between the load torque of the rotating shaft of the stirring blade and the crushed ratio of coarse particles (coarse adhering particles).

  The present invention has been made based on the above findings, and the gist thereof is as follows.

[1] A granulation facility for granulating a sintered raw material mainly composed of powdered iron ore into pellets,
A granulator equipped with a dish-like or cylindrical rotating body, and an agitation crushing device for agitating and crushing the sintered raw material during granulation and / or pellets after granulation in the granulator,
The stirring and crushing device includes a rotating shaft and a stirring and crushing member attached to the rotating shaft, and the number of rotations of the rotating shaft of the stirring and crushing device is based on the maximum value of the load torque generated on the rotating shaft. A granulation facility for sintered raw materials characterized by being determined.

  [2] The rotational speed of the rotating shaft of the stirring and crushing apparatus is determined to be a rotational speed in a range of 80% to 120% with respect to the rotational speed at which the load torque generated on the rotating shaft reaches a maximum value. The granulation facility for the sintering raw material according to the above [1].

[3] A granulation method for granulating a sintered raw material mainly composed of powdered iron ore into pellets,
A granulator equipped with a dish-like or cylindrical rotating body, and a stirring and crushing device that stirs and crushes the sintered raw material during granulation and / or the pellets after granulation in the granulator,
The stirring and crushing device is provided with a rotating shaft and a stirring and crushing member attached to the rotating shaft, and the rotation speed of the rotating shaft of the stirring and crushing device is the maximum value of load torque generated on the rotating shaft. A method for granulating a sintered raw material, which is determined based on

  [4] The rotational speed of the rotating shaft of the stirring and crushing device is determined to be a rotational speed in a range of 80% to 120% with respect to the rotational speed at which the load torque generated on the rotating shaft becomes a maximum value. The method for granulating a sintered raw material according to [3] above.

  In the present invention, even when powdered iron ore (fine powder ore, etc.) is used as the main sintering raw material, an appropriate particle size distribution can be obtained and the productivity of sintered ore can be easily and effectively maintained.・ I can improve.

It is a figure which shows the granulation equipment of the sintering raw material which concerns on one Embodiment of this invention. It is a figure which shows the example of the coarse grain crushing ratio in one Embodiment of this invention. It is a figure which shows the example of the load torque curve of the stirrer in one Embodiment of this invention. It is a figure which shows the control flow in one Embodiment of this invention. It is a figure which shows the productivity of the sintered ore in the Example of this invention.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a granulation facility for a sintering raw material according to an embodiment of the present invention.

  As shown in FIG. 1, a granulation facility 10 for a sintered raw material according to an embodiment of the present invention is a sintered material that is a mixture of powdered iron ore (fine ore, fine ore) as a main raw material and other auxiliary raw materials. The raw material 1 is granulated into a sintered raw material granulated product (pellet) 2, and is formed by a pan pelletizer (disk type granulator) 20 having a pan (dish-like rotating body) 21 and a pan pelletizer 20. It has a stirrer (stirring crushing device) 30 that stirs and crushes the sintered raw material 1 and / or the pellets 2 after granulation.

  The stirrer 30 includes a rotation motor 31, a rotation shaft 32 rotated by the rotation motor 31, and a stirring blade (stirring crushing member) 33 attached to the rotation shaft 32.

  In such a granulation facility 10 for the sintered raw material, the sintered raw material 1 is rolled and granulated by the pan pelletizer 20, and the sintered raw material 1 and / or pellets are rotated by the rotation of the stirring blade 33 of the stirrer 30. 2 is stirred and crushed.

  As described above, when a large amount of fine ore is blended in the sintering raw material 1, coarse adhered particles (coarse particles) with weak strength to which fine ores have adhered to each other increase, but as described above, the stirring blade 33 As a result, the coarse particles are crushed and the pellets 2 can be made uniform in particle size.

  However, the present inventors have found that the coarse particle breaking ability of the stirring crusher 30 varies depending on the rotation speed of the stirrer 30 (that is, the rotation speed of the rotating shaft 32 and the rotation speed of the stirring blade 33). However, the present inventors have found that there is a suitable number of rotations instead of increasing the number of rotations.

  That is, in FIG. 2, the rate of coarse particle breakage when the rotation speed of the stirrer 30 is changed to 40 rpm, 80 rpm, and 120 rpm (the generation of coarse particles relative to the number of coarse particles generated when the stirring and crushing device 30 is not used). An example of the number reduction ratio) is shown. In this example, when the rotational speed is 80 rpm, the ratio of coarse particles is maximized, indicating that it is most effective.

  As described above, the reason why the coarse particle breaking effect is reduced when the rotational speed of the stirrer 30 is too low or too high is as follows.

  That is, the relative speed at which the granulated product (sintered raw material 1 during granulation, pellet 2 after granulation) and the stirring blade 33 come into contact with each other varies depending on the number of revolutions of the agitator 30, and thus acts on the granulated product. The power changes. The granulated material is crushed when a force stronger than a certain threshold is applied depending on the particle size and particle structure. Therefore, since the relative speed of the granulated product and the stirring blade 33 increases as the rotational speed is higher, a large force is generated in the granulated product, and the coarse particles can be reliably broken.

  On the other hand, when the rotation speed of the stirrer 30 is high, the granulated material is repelled widely by the stirring blade 33, and the granulated material rolling in the pan pelletizer 20 is transferred to the stirring blade 33. The approaching flow is obstructed, and the contact probability between the granulated product and the stirring blade 33 decreases.

  In this way, the crushing ability of the stirrer 30 (stirring blade 33) is comprehensively determined by both the force acting on the granulated material and the contact probability, so that even if the rotation speed of the stirrer 30 is too low, Too much is not good.

  Next, FIG. 3 shows an example of the load torque curve of the stirrer 30 (that is, the load torque curve of the rotary motor 31 and the load torque curve of the rotary shaft 32) under the same conditions as in FIG. Similar to the coarse particle breaking rate, the load torque of the stirrer 30 is maximum when the rotational speed is 80 rpm.

  This is because the load torque is increased by crushing more coarse grains, and the maximum load torque in the load torque curve is the optimum load torque (optimum torque). .

  From the above, it is most effective if the stirrer 30 is operated at the rotation speed at which the coarse particle breakage ratio is maximized, but the coarse particle breakage ratio is maximized as shown in FIG. The number of rotations is directly determined because it takes time to investigate the coarse particle breakage ratio under various conditions. Therefore, as shown in FIG. 3, the number of rotations at which the load torque of the stirrer 30 is maximized. It is efficient to operate 30. Even if the conditions of the pan pelletizer 20 and the like change, it is only necessary to adjust the rotational speed in the direction in which the load torque of the stirrer 30 increases, and the rotational speed control of the stirrer 30 is easy.

  Therefore, in this embodiment, the rotational speed of the stirrer 30 (the rotational speed of the rotary shaft 32) is based on the maximum value of the load torque of the stirrer 30 (the load torque curve of the rotary motor 31 and the load torque of the rotary shaft 32). To decide.

  Specifically, the stirrer 30 (stirring blade 33) is rotated at a rotation speed at which the load torque of the stirrer 30 is maximized.

  FIG. 4 is a diagram showing a control flow in this embodiment.

  First, the stirrer 30 is based on the specifications of the stirrer 30 (size and shape of the stirring blade 33), material conditions (sintering raw material composition and moisture content), and operating conditions (the rotation speed and inclination angle of the pan pelletizer 20). The optimum torque is calculated. And granulation is performed while rotating the stirrer 30 (stirring blade 33) at the rotation speed at which the optimum torque is generated.

  Note that when the material conditions and operating conditions change, the optimum torque may change, so the optimum torque is calculated again and the rotation speed of the agitator 30 is changed.

  As described above, in this embodiment, the coarse particles can be effectively crushed by the stirrer 30 (stirrer blade 33), and even when a large amount of fine ore is blended, an appropriate particle size of the pellet 2 is obtained. Distribution can be realized, and productivity of sintered ore can be easily and effectively maintained and improved.

  Here, the stirring blade 33 is rotated at a rotation speed at which the load torque of the stirrer 30 is maximized. However, in some cases, the load torque of the stirrer 30 is maximum in consideration of the elasticity of operation. The stirring blade 33 may be rotated at a rotational speed in the range of 80% to 120% with respect to the rotational speed. For example, when the rotation speed at which the load torque of the stirrer 30 is maximum is 80 rpm, the stirring blade 33 may be rotated at 64 rpm to 96 rpm.

  In this embodiment, a disk type granulator (pan pelletizer) is used. However, the same operation can be performed even when a drum type granulator is used.

  In order to confirm the effect of the present invention, a granulation test of a sintered raw material was performed based on the above embodiment.

  The specifications and operating conditions of the pan pelletizer 20 are shown in Table 1, and the composition of the sintering raw material 1 is shown in Table 2.

  First, from the load torque curve of the stirrer 30, the rotation speed of the stirrer 30 that generates the optimum torque was calculated as 80 rpm.

  Therefore, as Comparative Example 1, the sintered raw material 1 was granulated without using the stirrer 30. Further, as Comparative Example 2, the sintered raw material 1 was granulated by rotating the agitator 30 at 120 rpm which does not become the optimum torque. Then, as an example of the present invention, the sintered raw material 1 was granulated by rotating the stirrer 30 at an optimum torque of 80 rpm.

  The result of having taken the sample of the pellet about each example, sintering the pellet, and evaluating productivity is shown in FIG. In FIG. 5, Comparative Example 1 is normalized as 1 and shown as a productivity index. Here, said productivity means the quantity per unit time which can produce the sintered ore provided with appropriate particle size and intensity | strength.

  As shown in FIG. 5, the productivity of the example of the present invention was improved compared to Comparative Examples 1 and 2, and the effects of the present invention could be confirmed.

1 Sintered raw material 2 Pellet (sintered raw material granulated product)
10 Sintering raw material granulation equipment 20 Bread pelletizer (disc type granulator)
21 bread (rotating plate)
30 Stirrer (stir crusher)
31 Rotating motor 32 Rotating shaft 33 Stirring blade (stirring crushing member)

Claims (4)

A granulation facility for granulating a sintered raw material mainly composed of powdered iron ore into pellets,
A granulator equipped with a dish-like or cylindrical rotating body, and an agitation crushing device for agitating and crushing the sintered raw material during granulation and / or pellets after granulation in the granulator,
The stirring and crushing device includes a rotating shaft and a stirring and crushing member attached to the rotating shaft, and the number of rotations of the rotating shaft of the stirring and crushing device is based on the maximum value of the load torque generated on the rotating shaft. A granulation facility for sintered raw materials characterized by being determined.   The rotational speed of the rotating shaft of the stirring and crushing apparatus is determined to be a rotational speed in a range of 80% to 120% with respect to the rotational speed at which the load torque generated on the rotating shaft becomes a maximum value. Item 2. A granulation facility for a sintering raw material according to Item 1. It is a granulation method for granulating a sintered raw material mainly composed of powdered iron ore into pellets,
A granulator equipped with a dish-like or cylindrical rotating body, and a stirring and crushing device that stirs and crushes the sintered raw material during granulation and / or the pellets after granulation in the granulator,
The stirring and crushing device is provided with a rotating shaft and a stirring and crushing member attached to the rotating shaft, and the rotation speed of the rotating shaft of the stirring and crushing device is the maximum value of load torque generated on the rotating shaft. A method for granulating a sintered raw material, which is determined based on   The rotational speed of the rotating shaft of the stirring and crushing apparatus is determined to be a rotational speed in a range of 80% to 120% with respect to the rotational speed at which a load torque generated on the rotating shaft becomes a maximum value. 4. A method for granulating a sintered raw material according to 3.

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