JP2001347228A - Sifting apparatus for lumpy raw material and sifting process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lumpy raw material sifting process in which the raw material with a particle diameter above a prescribed level is efficiently sifted out and the wide distribution of the particle diameters is achieved with the reduction of the residual or inclusive quantity of a small lump raw material. SOLUTION: A flat plate-like suspended member 8 formed of a flexible material is provided a the upper region of a sift body 5 and the lower end part of the flat plate-like suspended member 8 and the upper face 5a of a sift are properly spaced from each other and further, the flat plate-like suspended member 8 is installed long in the width direction of the sifting device. The upper end part of the flexible flat plate-like suspended member 8 is supported by the support member 9 of a vertically movable adjustment mechanism. The layer thickness of the lumpy raw material such as coke 8b loaded onto the upper face 5a of the sift is adjusted by means of the flexible flat plate-like suspended member 8. The layer thickness adjustment effect for the raw material becomes more conspicuous by shaping the flat plate-like suspended member 8 like a curtain. Consequently, the sifting efficiency is increased and the inclusion ratio of the small-lump raw material of a particle diameter below the target level into the processed raw material on the sift, is reduced and the distribution range of the particle diameter can be widened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for sieving coke, iron ore, and other bulk raw materials to prepare raw materials having a target particle size or more. When moving in the direction, by appropriately adjusting the thickness of the raw material layer and moving it smoothly so that the bulk raw material does not stay on the upper surface of the sieve, the raw material finer than the target particle size is efficiently sieved. The present invention relates to a technique for enlarging the distribution of raw material particle diameters after sieving.

[0002]

2. Description of the Related Art In blast furnace operation, control of the furnace interior material distribution is one of the most important operating factors. The reason is that the charge distribution governs the gas flow distribution in the blast furnace, whereby the heat exchange between the gas and the charge, the reduction and reduction of the ore, the level and shape of the softening zone and the coke The solution loss reaction and the like are defined, and therefore, the charge distribution has a significant effect on the operation results such as the fuel consumption, the tapping amount, the pig iron composition and the furnace condition. The control of the charge distribution currently performed in the blast furnace operation is performed by adjusting the layer thickness and the particle size of the charge in the radial direction in the furnace.

[0003] On the other hand, in recent blast furnace operations, pulverized coal injection, which blows pulverized coal from a tuyere to reduce the amount of coke used to reduce hot metal cost, has become the mainstream. Technology development to increase the number is being actively carried out. However, coke has conventionally been designed to have a larger particle size than ore, and it not only serves as a fuel or a reducing agent for iron ore, but also serves as a spacer that keeps voids in the furnace and ensures its permeability. I'm making it. By the way, pulverized coal is used as a partial substitute for coke. Therefore, as the pulverized coal injection amount is increased, the coke amount is reduced, and the permeability in the blast furnace is deteriorated accordingly. The method mainly used for improving the air permeability in the furnace is the above-described control of the furnace interior material distribution. Based on past operational experience and theoretical calculations, it is effective to create a state of good air permeability in the axial center of the furnace in the radial direction in order to reduce the pressure loss in the furnace during a large pulverized coal injection operation. Therefore, it has been found that a method of forming a layer of coke having a larger particle size than the ore or the auxiliary material at the shaft center of the furnace is effective. As described above, the coke charged into the shaft portion of the blast furnace (hereinafter referred to as “center charged coke”) has a large average particle diameter and a small proportion of fine particles (small coke). Desirable from the viewpoint of ensuring internal ventilation.

Conventionally, in a steel mill or the like, a lump material such as coke, iron ore, or sinter used as a material is subjected to a sieving treatment, and small particles or small lump portions are sieved to remove the sieved material. When prepared and used in a production process, various bulk materials are processed by a sieving apparatus. FIG. 6 shows a schematic side view illustrating the state of the coke sieving process using a sieving apparatus example, taking coke for a blast furnace as a lump material, and a schematic plan view of a sieve bar provided on the upper surface of the sieve of the apparatus. FIG. 7 shows an enlarged view of a main part of the coke sieving process state of FIG. As shown in FIG. 6A, the coke hopper 1 in the coke supply device
Open the cutting device 2 provided at the bottom material supply port,
The coke 3 is charged into the sieve body 5 of the sieving device 4.

[0005] The sieve main body 5 constitutes the main part of a sieving apparatus, for example, three continuous sieves along an inclined surface, and the upper surface 5a of the sieve vibrates appropriately within a certain plane. Sieve upper surface 5 of each sieve body 5
In FIG. 6A, a plurality of sieve bars 6 as shown in FIG.
Are arranged in parallel with each other at a predetermined interval from each other in the direction of line movement indicated by the arrow in the figure. While the coke 3 charged on the sieve upper surface 5a moves on the sieve bar 6 in the line direction,
The small-grain portion is sieved from the gap of the sieving bar 6, and the on-screen coke 3 a having a predetermined particle size or more is discharged from the discharge side in the traveling direction of the sieving device 4. In this way, coke having the target particle size is prepared and transported to the blast furnace in the next step.

In the above process, the adjustment of the supply amount of coke 3 to the sieve body 5 is performed by opening the cutout device 2.
Next, the top and bottom of the layer thickness adjusting plate 7 provided above the sieve body 5
By the tilting operation, the distance between the layer thickness adjusting plate 7 and the upper surface 5a of the sieve is adjusted so that the coke 3 is moved in the line direction indicated by the arrow in FIG. When moving to, adjustment is made to form an appropriate coke layer thickness. Here, the setting of an appropriate coke layer thickness means that small particles or small lump coke having a target particle size or less in the coke layer is quickly sieved and the mixing ratio of small particles or small lump coke remaining in the on-sieve coke is reduced. Therefore, in order to increase the average coke particle size and increase the processing efficiency, the coke moving amount moving on the sieve body 5 is set to be large.

[0007]

However, there are the following problems in the operation of adjusting the opening degree of the cutting device 2 performed to adjust the coke supply speed from the coke hopper 1 to the sieving device 4. That is, in the method of providing the steel plate gate 2a and adjusting the opening area by adjusting the opening degree of the gate 2a to adjust the amount of coke flowing from the coke hopper 1 to the sieve body 5, the gate 2a is used to suppress the coke outflow amount. When the opening degree of the coke is reduced, when the large coke based on the variation in the coke particle size comes out of the coke hopper 1, the coke overlaps and stays at the outlet of the gate 2 a, and the subsequent coke 3 flows out onto the sieve body 5. In some cases, the sieving process efficiency is greatly reduced. On the other hand, when the opening degree of the gate 2a is increased and the amount of coke flowing out is increased, the coke layer thickness of the upper surface 5a of the sieve becomes too thick than an appropriate value. It moved on the sieve together with large lump coke while being sandwiched inside the coke layer, and remained in the on-sieve coke 3a. Mixed. As a result, the residual mixing ratio of small coke having a target particle size or less into the sieved coke is increased, and the average particle size of the coke is reduced.

[0008] The above-mentioned problems in the sieving of massive coke are also caused in the sieving process of massive raw materials such as ores and sintered ores. Accordingly, an object of the present invention is to eliminate the clogging / stagnation phenomenon of the large bulk material at the exit of the cutout gate from the bulk material supply hopper in the bulk material sieving process, improve the processing efficiency, and furthermore, increase the screen upper surface 5a. By preventing the raw material layer thickness from becoming too thick, the residual / mixing ratio of small-sized or small-sized raw material having a target particle size or less is reduced as much as possible, and the average particle size of the raw material on the screen after processing is increased. To provide a mass raw material sieving apparatus and a sieving treatment method.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies from the above-mentioned viewpoints, and have obtained the following findings. That is, in the mechanism for adjusting the thickness of the raw material layer formed on the upper surface of the sieve provided in the sieving apparatus for the bulk raw material, in order to sufficiently exhibit the original function required for the raw material layer thickness adjusting plate, A flexible material is used for the layer thickness adjusting plate, and the mounting posture and shape of the raw material layer thickness adjusting plate are optimized, and a gap adjusting mechanism between the upper surface of the sieve and the lower end surface of the raw material layer thickness adjusting plate is provided. It has been found that the intended purpose can be achieved by adopting the configuration.

[0010] The present invention has been made based on the above findings, and the gist thereof is as follows. The bulk raw material sieving apparatus according to the first aspect of the present invention is provided with the following plate-shaped hanging member at an upper portion of the main screen of the bulk raw material sieving apparatus. That is, it is a flat member having a predetermined width in the width direction of the sieve body of the sieving apparatus, a predetermined height in the vertical direction, and a vertically lower end edge constituting an unconstrained free end and vertically hanging down. The lower end surface of the flat hanging member is parallel to the upper surface of the sieve body and is located above the upper surface with a predetermined interval between the upper surface of the sieve body, and the upper end portion of the flat hanging member. Is formed to be long in parallel with the width direction of the sieve main body, is supported at a predetermined height position from the upper surface of the sieve by a predetermined vertical movable adjustment mechanism, and furthermore, the flat hanging member has a flexible material. It is composed of

[0011] The sieving apparatus for bulk raw materials according to the second aspect of the invention is characterized in that, in the first aspect of the invention, the flat hanging member is made of hard rubber. Things.

According to a third aspect of the present invention, there is provided an apparatus for sieving a lump raw material according to the first or second aspect, wherein the flat hanging member is divided into two or more sheets in the width direction of the member. It is characterized by having a noren-like form.

The sieving treatment method of the bulk raw material according to the fourth aspect of the present invention is as follows. That is, a sieving process is performed on the bulk raw material charged on the upper surface of the sieve of the sieving apparatus to prepare a large-diameter raw material having a target particle size or more to be prepared. A flexible flat member is vertically suspended above the upper surface of the sieve, and the clearance between the upper surface of the sieve and the lower end of the flexible flat member is set to a predetermined value, and the flexible flat plate is disposed. While using a shaped member, while limiting the raw material layer thickness of the bulk raw material that is loaded on the upper surface of the sieve immediately below the flexible flat member and passes along the sieving line, It is characterized in that it passes through the installation position.

According to a fifth aspect of the present invention, in the method of the fourth aspect, the set clearance between the upper surface of the sieve and the lower end of the flexible plate-like member is reduced. It is characterized in that it is adjusted according to the particle size of the massive raw material charged on the upper surface.

According to a sixth aspect of the present invention, in the method of the fourth aspect, the set clearance between the upper surface of the sieve and the lower end of the flexible flat member is reduced. It is characterized in that it is adjusted in accordance with the target particle size to be prepared of the bulk raw material after the dividing treatment.

[0016]

Next, the present invention will be described with reference to the drawings. FIG. 1 shows a side view of a main part of a preferred sieving apparatus for a bulk material according to the present invention. FIG. 5 shows a conventional coke sieving apparatus shown in FIG. 6 in which the sieve body 5 in the upstream part in the line traveling direction and the coke 3
b and a portion corresponding to the place where the raw material layer thickness adjusting plate 7 is provided, and is provided in place of the main part of the sieving process according to the conventional method shown in FIG. FIG. 6 is a diagram for explaining a main part of the process according to FIG. In FIG.
The coke 3 charged into the upper surface 5a of the sieve main body 5 through the opening of the gate 2a of the cutting device 2 from the coke hopper 1
b is a material layer thickness adjusting plate 7 provided conventionally,
The coke charged by the flat hanging member 8 made of a flexible material and provided at a position above the sieve body and slightly away from the exit of the gate 2a in the line traveling direction. The layer thickness of 3b is adjusted.

The flexible plate-shaped hanging member 8 is made of hard rubber or the like, and has a width substantially the same as the width of the sieve body 5 in the width direction of the sieve body 5 and the gate 2a. The upper end is located at a position sufficiently higher than the top of the layer thickness of the coke 3b charged from above. The level at the lower end is above the upper surface 5a of the sieve, and the target particle size of the coke to be prepared (in the present invention, a coke having a predetermined particle size (d) or more is to be prepared. Diameter (d)), e.g.
The length in the height direction of the flexible plate-shaped hanging member 8 is determined so as to be located at a height of about 1.5 times. The upper end of the flexible flat hanging member 8 is supported by a support member 9 of a lower movable adjustment mechanism (not shown) capable of adjusting the position in the vertical direction. Therefore, the lower edge of the flexible flat hanging member 8 forms an unconstrained free end. As described above, the flexible flat-plate hanging member 8, the supporting member 9, and the up-down movable adjusting mechanism (not shown) constitute the bulk raw material layer thickness adjusting device 10, which is an important component of the apparatus of the present invention.

The form of the flexible plate-shaped hanging member 8 is desirably divided into two or more in the width direction to form a goodwill. At the divided boundary, there is little or no gap, and the gap is made smaller than the target particle size of the raw material. At that time, the number of divisions depends on the width of the sieve body 5,
It is desirable that the width of one sheet after the division be several times the target particle diameter of the raw material. FIG. 2 is a schematic front partial view illustrating a positional relationship between a flexible flat hanging member and a main sieve body in the sieving apparatus of the present invention. As shown in FIGS. 1 and 2, the flexible flat hanging member 8 (8 ′) is desirably provided near the downstream side of the sieve body 5 at the upstream side. FIG. 2 exemplifies a curtain-like flexible flat-plate hanging member 8 '. Further, as shown in FIG. 3, the form of the flexible flat plate-shaped hanging member 8 ″ may be formed in the shape of a noren.

In the present invention, since the bulk raw material sieving apparatus is configured as described above, the following operations and effects are exhibited.

1. The bulk material layer thickness adjusting device 10 is
And the flat hanging member 8 is made of a flexible material.
When the layer thickness of the coke 3b is larger than the set clearance between the upper surface 5a of the sieve and the lower end of the flexible plate-shaped hanging members 8, 8 ', 8 "when moving in the line traveling direction, When the lower portions of the shape-pending members 8, 8 ', 8 "slightly bend in the traveling direction, the layer thickness of the coke 3b becomes slightly thicker than the initially set layer thickness, and the coke 3b to be subsequently fed is reduced. The movement is prevented from staying or stopping. Thereafter, when the layer thickness of the coke 3b to be charged is reduced to an appropriate thickness as before, the lower shape of the flexible flat plate-shaped hanging members 8, 8 ', 8 "returns to the original shape. Then, the initially set clearance is maintained again, so that the upper surface 5a of the sieve always approaches an appropriate coke layer thickness, and as a result, the coke on the sieve after the sieve treatment (see 3a in FIG. 6). The ratio of small or small coke remaining or mixed therein is reduced, and the average coke particle size is also increased, and the lower shape of the flexible plate-shaped hanging members 8, 8 ', 8 "as described above is reduced. Due to the deformation, the coke 3b charged during this time is removed from the gate 2 of the coke hopper 1.
Since there is no stagnation near the outlet a, the sieving efficiency is also improved.

2. Flexible flat hanging member 8, 8 ', 8 "
Is supported by a support member 9 of a vertically movable adjustment device (not shown), so that when the particle size of the bulk material charged on the upper surface 5a of the sieve fluctuates to large or small, the supporting member 9 9 can be raised or lowered by an appropriate distance, respectively. Therefore, the distance between the upper surface 5a of the sieve and the lower ends of the flexible flat hanging members 8, 8 ', 8 "can be set to an appropriate distance. Also, the target grain of coke to be prepared by the sieving process can be set. The above-mentioned interval can be appropriately set according to the diameter, and as a result, the same effect as in the above item 1 can be obtained.

3. Flexible flat hanging member 8, 8 ', 8 "
Is in the shape of a noren, so that the flexible plate-shaped hanging members 8, 8 ', 8 "are arranged in the width direction with respect to the variation in the thickness of the charged coke 3b in the width direction of the sieving apparatus. Therefore, it is possible to make an appropriate deformation, so that the particle size distribution of the sieve-on-screen coke 3a (see FIG. 6A) in the width direction is made uniform. The use of the members 8, 8 ', 8 "has an effect of moving the charged coke 3b in the width direction, so that the effect of reducing the width-direction variation of the charged coke 3b layer thickness is exhibited.

4. Flexible flat hanging member 8, 8 ', 8 "
Is very simple and its inspection and maintenance are easy. And the equipment cost and maintenance cost are also low.

The raw material is treated by using the bulk raw material sieving apparatus according to the present invention to prepare a large particle size raw material having a target particle size or more. At that time, the clearance between the upper surface of the sieve and the lower end of the flexible flat member is set to an appropriate value. Here, the appropriate set value of the clearance should be determined according to the target particle size that is equal to or larger than the target particle size, and cannot be determined uniquely. However, the target particle size of the raw material to be prepared (in the present invention, ,
It is intended to prepare one having a predetermined particle size or more,
It is desirable that the predetermined particle size is d), for example, about 1 to 1.5 times. By doing so, small-sized or small-sized raw materials having a target particle size or less remain in the processed sieve raw materials.
This is because the mixing ratio is reduced. In that case, the average particle size of the raw material also increases. In addition, at the place where the raw material is charged on the upper surface of the sieve, the raw material charged is appropriately changed depending on the variation in the particle diameter of the raw material so that the raw material does not clog or stay.

The above-mentioned 1. ~ 4. The same operation and effect can be obtained even if the raw material to be sieved is a lump material other than coke. Therefore, in the process of manufacturing an industrial product, when the bulk raw material is sieved to prepare particles having a particle size larger than a predetermined particle size, the sieving apparatus and the sieving process described above for coke are used. The method is also applicable to the manufacturing process of an industrial product.

[0026]

EXAMPLES The present invention will be further described with reference to examples. In the blast furnace operation, in the preparation process of the so-called "center charging coke" used for charging the shaft center portion, the sieving apparatus and the sieving method of the bulk material of the present invention were implemented. FIG. 4 is a schematic diagram showing a process of preparing coke produced in a coke oven into a centrally charged coke and then charging the coke into a blast furnace. After the coke 3 produced in the coke oven 12 is subjected to preliminary sieving by the primary sieving device 13, the coke hopper 1
Transfer and charge to A massive coke 3 is cut out from the coke hopper 1 and charged into the massive raw material sieving device 4 according to the present invention described with reference to FIGS. 1 and 3, and the massive coke 3 is subjected to the target granulation by the sieving treatment method of the present invention. An on-screen coke 3a as a large lump having a diameter or more was obtained. This is transferred to the blast furnace 14 by a predetermined transfer device, and the central charging coke 1
Charged as 5.

During the above operation, the average particle size and harmonic average particle size, and -25 mm and -50 mm for the center charged coke 15 (Example) obtained according to the present invention.
FIG. 5 shows the mixing ratio of the particle size coke. In addition, the result about the center charge coke (comparative example) obtained by processing using the conventional bulk raw material sieving apparatus described in FIGS. 6 and 7 is also shown.

When the results obtained in the examples according to the present invention were compared with the results obtained in the comparative example according to the prior art, the particle size was large and the mixing ratio of small coke was significantly reduced. For example, for the average particle size of the central charging coke,
What was conventionally 70 mm was increased to 75.2 mm, and the mixing ratio of small coke under 50 mm was 9.7 mass%, which was conventionally 16 mass%.
Decreased to. Along with this, the yield of the central charging coke was increased from the conventional 70 mass% to 80 mass%, and a remarkable improvement effect was recognized.

[0029]

According to the present invention, the layer thickness of the bulk material can be adjusted by the sieving device without causing the material moving on the upper surface of the sieve to stay, so that the processing efficiency is improved and the target particle size is improved. It is possible to reduce the mixing ratio of the small-diameter raw material having a diameter equal to or less than the raw material on the processed raw material on the sieve, thereby increasing the particle size distribution. Therefore, when the apparatus and method of the present invention are applied to, for example, the preparation of coke charged in the center of a blast furnace, it contributes to control of the distribution of materials inside the blast furnace and is effective in improving air permeability in the furnace. An apparatus and a method for sieving such a bulk material can be provided, and an industrially useful effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of a preferred sieving apparatus for a bulk material according to the present invention.

FIG. 2 is a schematic front partial view illustrating a positional relationship between a flexible flat hanging member and a sieve main body in the sieving apparatus of the present invention.

FIG. 3 is a schematic front view showing an example of a flexible flat-shaped hanging member having a stepped curtain in the screening device of the present invention.

FIG. 4 is a schematic flow chart showing a process in which coke produced in a coke oven is subjected to a sieving process by the technique of the present invention to prepare a coke charged centrally in the blast furnace and then charged into the blast furnace.

FIG. 5 is a graph comparing the particle size of the central charging coke as the sieved coke and the mixing ratio of small lump coke between the example and the comparative example.

FIG. 6 is a schematic side view illustrating a conventional coke sieving process.

FIG. 7 is an enlarged view of a main part of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coke hopper 2 Cutting-out apparatus 2a Gate 3 Coke (mass raw material) 3a Coke on a sieve 3b Coke charged 4 Sieving apparatus 5 Sieve main body 5a Sieve upper surface 6 Sieve bar 7 Layer thickness adjusting plate 8 Flexible flat hanging member 8 ', 8 "Noren-shaped flexible flat-plate hanging member 9 Support member 10 Mass raw material layer thickness adjusting device 11 Frame 12 Coke oven 13 Primary sieving device 14 Blast furnace 15 Central charging coke

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Minoru Kuwahara 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd. (72) Inventor Koji Morekane 1-1-2, Marunouchi, Chiyoda-ku, Tokyo F-term (reference) in Nippon Kokan Co., Ltd. 4D021 AA03 AB04 CA07 CB20 DC10 EA05 4H012 GB00 4K001 AA10 BA02 BA05 BA24 CA02 CA47 CA49

Claims (6)

[Claims] 1. An apparatus for sifting a lump of raw material, which is located above a sieve body, has a predetermined width in a width direction of the sieve body, has a predetermined height in a vertical direction, and has a lower edge. Is a flat member that constitutes an unconstrained free end and vertically hangs down, and the lower end surface of the flat hanging member is parallel to the upper surface of the sieve body and a predetermined distance between the upper surface and the upper surface of the sieve. It is located above with an interval, while the upper end of the flat hanging member is formed to be long in parallel with the width direction of the sieve body,
It is supported at a predetermined height from the upper surface of the sieve by a predetermined vertically movable adjustment mechanism, and the flat hanging member is made of a flexible material. Sieving device. 2. A material according to claim 1, wherein said plate-shaped hanging member is made of hard rubber.
An apparatus for sifting bulk raw materials as described above. 3. The bulk raw material according to claim 1, wherein the flat hanging member is divided into two or more pieces in a width direction of the member to form a goodwill shape. Sieving device. 4. A method for sieving a bulk raw material, which comprises sieving the bulk raw material charged on the upper surface of a sieve of a sieving apparatus to prepare a raw material having a large particle diameter larger than a target particle diameter to be prepared. The flexible flat member is vertically suspended above the upper surface of the sieve in advance, and the clearance between the upper surface of the sieve and the lower end of the flexible flat member is set to a predetermined value and disposed. Using a flat plate member, while restricting the raw material layer thickness of the bulk raw material that is loaded on the upper surface of the sieve immediately below the flexible flat member and passes along a sieving line, the flexible flat member A method of sieving a bulk raw material, wherein the raw material is passed through an installation position. 5. The set clearance between the upper surface of the sieve and the lower end of the flexible flat member is adjusted in accordance with the particle size of the bulk raw material charged on the upper surface of the sieve.
A method for sieving the bulk raw material according to the above. 6. A set clearance between the upper surface of the sieve and the lower end of the flexible flat member is adjusted according to the target particle size of the bulk material to be prepared after the sieving process. The method for sieving a bulk raw material according to claim 4.