JPH07268495A - Production of sintering ore and raw material charging device of dwight-lloyd type sintering machine - Google Patents

Abstract

PURPOSE:To form gaps securing the air permeability of the intermediate layer of a sintered layer on the area excluding the brittle part of the upper layer area of a raw material bed chared to the surface of a pallet without disturbing the deposition of the raw material and to secure a uniform gaseous flow and air permeability in the sintered layer. CONSTITUTION:In a Dwight-Lloyd type sintering machine, at first, the surface of the floor of a pallet moving from a feeding stage of a raw material to a sintering stage is paved with paving sintering ores fed from a paving hopper. Next, the surface of the paving sintering ores is charged with the raw material from a raw material surge hopper 4 to form a deposited layer of the raw material and plural planar bodies 11 arranged at intervals in the pallet width direction are inserted into the flank 5a on the paving surge hopper 4 of the raw material deposited layer while they are rotated. Plural vent glooves 12 are notchedly formed on the flank 5a, and after that, the raw material deposited layer is sintered.

Description

Detailed Description of the Invention

[0001]

This invention relates to maintaining a uniform gas flow and securing air permeability in a raw material layer on a pallet during a sintering process when a sinter is manufactured by a Dwightroid type sintering machine. It relates to a method to be achieved and a raw material charging device used for this method.

[0002]

2. Description of the Related Art As shown in FIG. 1, the production of sinter using a Dwightroid-type sinter machine circulates and moves a pallet 1.
First, the bedding sinter 3 from the bedding hopper 2 is spread, and the sinter ore raw material 5 cut out from the surge hopper 4 is passed through the drum feeder 6, the sloping chute 7 and the cut plate 8. A charge of a fixed layer thickness is provided, and in the downstream region thereof, an ignition furnace 9 using a plurality of fuel burners arranged in the width direction of the pallet ignites the upper layer portion of the raw material and a wind box under the pallet 1 (not shown). The material 5 on the pallet 1 is sintered while the pallet 1 moves toward the terminal end side by suction from.

Specifically, in order to protect the pallet from overheating and prevent the raw materials from falling, a bedding sinter having a thickness of 20 to 30 mm is spread over the pallet, and a thickness of about 500 to 700 mm is applied on the sinter. The raw material is charged, and in that case, coarse particles are segregated in the lower layer and fine particles are segregated in the upper layer in order to increase the porosity of the raw material layer as much as possible.

Since this Dwightroid-type sintering machine is of the downward suction type as described above, the raw material layer in the sintering process is, as shown in FIG. A strong sinter layer (b), a combustion melt layer (c), a dry layer (d) and a wet layer (e) are formed. Here, water is added to the raw material in order to ensure air permeability by forming the pseudo particles, but this water evaporates in the upper layer region of the raw material layer and condenses in the lower layer wet layer, significantly impairing air permeability. Cause In particular, in the lower layer of the raw material layer (hereinafter referred to as the raw material bed) that has a certain thickness through the cut plate, the cooling rate becomes slower than in the upper layer area, so the heat retention effect is large and the red tropics are enlarged. However, the gas permeability is impaired due to the expanded molten layer, and uneven flow of the gas flow occurs due to uneven melting.

This phenomenon is further promoted when an inexpensive high crystal water ore is used as a raw material ore. That is, when a high crystal water ore is used as a raw material ore, the amount of water that enters the ore is large, and thus the amount of water added to secure the air permeability by forming the above pseudo particles naturally increases, When they are dried in the dry layer and condensed in the wet layer, the moisture content of the wet layer becomes excessively large, and the degree of impairing air permeability becomes extremely large. Further, since the highly crystallized water ore has many pores, it is easier to melt than the ordinary ore, and the molten layer tends to expand in the sintering bed as compared with the case where the ordinary ore is used. Therefore, the use of high crystal water ore promotes deterioration of air permeability and occurrence of drift.

[0006] The deterioration of air permeability and the occurrence of nonuniform flow cause uneven burning of the sinter or decrease in sinter strength and decrease the productivity of the sinter, so that the air permeability in the lower layer area of the raw material bed is ensured and uniform. It is essential to maintain a stable gas flow.

Therefore, in order to improve the obstruction of the air permeability of the sintering raw material layer and prevent the uneven flow, for example, JP-A-61-136637 is used.
In the publication, on the upstream side between the raw material supply device and the ignition device, a void is formed by a void forming device such as a ventilation rod to the middle layer of the sintering raw material layer on the pallet having poor air permeability,
A method has been proposed in which the air permeability of the sintered layer is adjusted by pressing the upper layer having good air permeability on the downstream side. Similarly, Japanese Patent Application Laid-Open No. 61-194120 discloses a method of adjusting the porosity of the raw material layer between the raw material charging device and the ignition furnace by mechanical means. However, in these methods, as shown in FIG. 2, since voids are preliminarily formed in the region where fragile sinter is generated, there is a problem that the fragile sinter becomes more fragile.

On the other hand, in Japanese Patent Laid-Open No. 2-26935, a plurality of air permeability control rods having one fixed end are provided between the floor ore sinter feed unit and the sinter raw material feed unit in the pallet layer to the lower layer. It is disclosed that it is inserted in the traveling direction to improve the air permeability of the lower layer portion of the sintered layer. According to this method, small-diameter holes extending in the pallet advancing direction are formed so as to be scattered in the cross section of the raw material layer, but there is little contribution to improving the air permeability of the lower layer portion. That is, in order to obtain a greater effect of improving air permeability, a large number of air permeability control rods are required, and in that case, the deposition of the raw material in the raw material supply section is greatly disturbed, resulting in uneven burning and sintering strength. It causes a defect.

Further, Japanese Patent Laid-Open No. 5-295456 discloses a server.
A method has been proposed in which a plurality of air-permeability control rods are inserted almost vertically into the slope of the raw material deposited on the pallet through a hopper and a sloping shoe, and a ventilation groove is formed to improve air permeability. . Although this ventilation groove improves the ventilation, since the raw material deposition layer that moves together with the pallet is scraped off by the rod fixed vertically to form the ventilation groove, the shape of the formed ventilation groove is not constant, and The grooves once formed are likely to collapse along with the movement of the pallet, which greatly disturbs the distribution of the ventilation grooves, and the desired air permeability may not be obtained.

[0010]

Therefore, the present invention is
In the upper layer area of the raw material bed charged on the pallet, a void is formed in the upper layer area of the sintered layer, which does not disturb the deposition of the raw material, to ensure air permeability in the intermediate area of the sintered layer. It is an object of the present invention to provide a method for achieving uniform gas flow and ensuring air permeability, together with a raw material charging device used in this method.

[0011]

The present invention is a dwightroid type sintering machine in which a bedding sinter supplied from a bedding hopper is first placed on a floor of a pallet which moves from a raw material supply process to a sintering process. Then, the raw material is charged from the raw material surge hopper onto the bedding sinter, and a deposited layer of the raw material is formed.
A plurality of plate-like bodies arranged at intervals in the pallet width direction are inserted into the slope of the bedding floor hopper side of the raw material deposit layer while rotating, and a plurality of ventilation grooves are formed in the slope to form the raw material. This is a method for producing a sintered ore characterized by sintering a deposited layer. Particularly, it is desirable to form a cut of a ventilation groove while removing a raw material adhering to a plate-shaped body.

Here, it is advantageous in practice that the ventilation groove is formed in a range from the pallet floor surface to 2/3 of the height of the raw material bed and the raw material contains high crystal water ore.

Further, in the above method, in a Dwightroid type sintering machine, a pallet filled with bedding sinter supplied from a bedding hopper is spread through a surge hopper, a drum feeder, a sloping chute and a cut plate. A raw material charging device for depositing raw material on a pallet, wherein a rotary shaft extending in the pallet width direction is installed near the slope of the floor hopper side of the raw material deposition layer so as to be movable in the pallet advancing direction and the raw material depositing direction. However, a raw material charging device of a Dwightroid-type sintering machine, which is formed by fixing a plurality of plate-shaped bodies to the rotating shaft, can be used. Here, the plate-shaped body may be provided with a scraper for scraping off the raw materials attached thereto,
It is advantageous for implementation.

Now, FIG. 3 shows a raw material charging device of the Dwightroid type sintering machine used in the method of the present invention. With this raw material charging device, the raw material 5 cut out from the surge hopper 4 is deposited on the pallet 1 with a constant layer thickness through the drum feeder 6, the sloping chute 7 and the cut plate 8. At this time, the slope 5a on the floor hopper side of the deposited layer of the raw material is deposited according to the angle of repose, and the raw material bed 5b is formed on the ignition furnace side.

Then, in the vicinity of the slope 5a, the pallet 1
A rotary shaft 10 extending in the width direction is provided at a position where it does not interfere with the pallet 1 at all, and a plurality of plate-like bodies, in the illustrated example, disks 11 are fixed to the rotary shaft 10 at substantially equal intervals, and the rotary shaft 10 is used as a raw material. It is configured to be movable in the stacking direction, that is, the height direction of the raw material bed 5b and the traveling direction of the pallet 1. Therefore, since the disc 11 fixed to the rotating shaft 10 can be moved back and forth with respect to the slope 5a of the raw material deposit layer, as shown in FIG. By inserting in the advancing direction, the ventilation groove 12 having a size corresponding to the insertion depth of the disk 11 into the raw material deposition layer can be cut and formed.

For example, as shown in FIG. 4, if the disk 11 located at the A position is moved to the B position, it is possible to reach a higher position in the middle region of the sintering raw material layer above the bedbed ore 3 layers. Vent groove extending
12 are formed. Similarly, by moving the disk 11 from the position A to the position C above the raw material bed in the height direction, it is possible to form the ventilation groove 12 in the center of the intermediate region of the sintering raw material layer.

The position of the ventilation groove is mainly changed depending on the raw material situation, but in any case, it is necessary to form it in a region excluding the surface region of the raw material bed. This is because the surface area of the raw material bed has a small drop from the sloping chute, therefore the packing density is small and the porosity is large. Since it becomes a layer, further forming a ventilation groove in this portion deteriorates quality such as sinter strength.

Further, since sinter having a large particle size is used in the bed ore layer, it is not necessary to ensure air permeability, and conversely, it is not preferable to form the ventilation groove from the viewpoint of preventing the raw material layer from falling. Ventilation grooves are formed in the area above the bed deposit.

As described above, by forming the cut using the rotating disk 11, the ventilation groove having a predetermined shape is surely formed in the lower layer region in the raw material deposit layer in the pallet, and the subsequent sintering process. In addition to avoiding the non-uniform gas flow caused by the non-uniform melting, the air permeability is improved.

It is preferable that the disc 11 is rotated in a direction opposed to the flow of the raw material on the slope of the raw material for reliable formation of the ventilation groove. Furthermore, the rotation speed is 4 to 10 r.
It is preferably about pm. That is, since the ventilation groove in the middle and lower layers of the raw material is stably formed by pressing the raw material in the vicinity of the side surface of the disk by rotation, the pressing force is small and the formed groove collapses when the rotation speed is less than 4 rpm. Cheap. On the other hand, if it exceeds 10 rpm, the particles will collapse, and the powder after the collapse will accumulate directly under the disc, obstructing aeration.

Further, when the disc 11 is inserted into the raw material deposition layer,
There is a possibility that the raw material adheres to the circular plate 11 and the deposited state of the raw material is greatly disturbed, and uneven burning and poor sintering strength are rather promoted. Therefore, in the raw material charging device shown in FIG. 3, as shown in FIGS. 5 (a) and 5 (b), the scraper 13 placed close to the disc 11 scrapes off the raw material adhering to the disc 11. I chose That is, the scraper 13 is composed of an iron brush disposed opposite to the side surface of the disk 11 and an iron plate made of a wear-resistant material that supports the brush, and the scraper 13 is pressed against the disk 11 to scrape off the raw material.

The rotary shaft 10 of the disk 11 is supported by a frame 14 installed below the drum feeder 6 via a bracket 15, and a motor 16 with a reducer installed on the frame 14 via a chain 17. The motor 10 is connected and the rotary shaft 10 is driven by the driving force of this motor 16.
And rotate the disc 11. Although a circular plate is shown in the illustrated example as the plate-like body forming the ventilation groove, it may be a polygonal plate, an elliptical plate, or the like, and any shape may be used as long as the ventilation groove can be formed.

Further, in the plate-shaped body, if the thickness is less than 10 mm, the ventilation effect of the obtained groove is small, and if it exceeds 30 mm, the formed groove becomes excessively large, the gas flow is concentrated in the groove, and uneven burning occurs. Therefore, the proper thickness is 10 to 30 mm. Also,
The plate diameter is preferably about 600 mmφ so as not to cut the ventilation groove in the bed height direction and to prevent the rotating shaft for rotating the plate-shaped body from entering the raw material slope.

Further, the number of the plate-shaped members is not particularly limited, but in order to obtain a good gas flow, the interval between the plate-shaped members is 100 to 400 depending on the height of the raw material deposition layer on the pallet 1.
It is preferable to set the number of sheets to be mm. This is because if the distance is less than 100 mm, the number of ventilation grooves becomes too large and the strength of the sinter becomes insufficient, while if it exceeds 400 mm, the effect of the ventilation grooves cannot be expected.

[0025]

In the method of the present invention, since the rotating plate-like body is charged into the raw material deposition layer to form the ventilation groove by cutting,
A ventilation groove having a desired shape can be stably obtained, and the ventilation groove once formed does not collapse with the movement of the pallet. This is because the particles of the raw material are not consolidated on the side surface side of the disk by rotating the plate-like body, and the once formed ventilation groove does not collapse as the pallet moves. In the above-mentioned Japanese Patent Laid-Open No. 5-295456, since the raw material is scraped off by the ventilation rod, there is a possibility of returning to the original filling structure after the ventilation rod has passed.

[0026]

【Example】

Example 1 Using the raw materials having the formulations shown in Table 1, the productivity when the sinter was produced under the operating conditions shown in Table 2, the air permeability during the sintering, and the quality of the obtained sinter were investigated. Results are shown in FIG.

[0027]

[Table 1]

[0028]

[Table 2]

In this embodiment, as shown in FIGS. 3 to 5, a rotary shaft having 25 discs (thickness: 20 mm and diameter: 600 mm) fixed at 200 mm intervals in the pallet width direction is provided with a reduction gear motor. While rotating with, insert a disk into the raw material deposition layer and change the height from the pallet floor surface at each position of 50, 100 and 150 mm (hereinafter referred to as the ventilation groove height) within the range of 50 to 300 mm. Formed ventilation grooves. All the formed ventilation grooves had a substantially constant shape, and the ventilation grooves did not collapse with the movement of the pallet.

For comparison, a ventilation groove was also formed by inserting 20 mmφ round bars in the vertical direction with respect to the slope of the raw material deposition layer at the same intervals as in the above embodiment. The evaluation in this operation is also shown in FIG.

As is apparent from FIG. 6, by forming the ventilation groove in the lower layer region of the sintering raw material layer which does not collapse even when the pallet is moved, the drop strength and the yield are not adversely affected, and the productivity is improved. As a result, the energy intensity has improved significantly.

Further, by forming the ventilation groove,

[Equation 1] Is significantly improved at any ventilation groove height,
If the ventilation groove height exceeds 300 mm, the sinter ore strength tends to decrease, and the rate of return ore increases. In other words, if ventilation grooves are formed in a region above 2/3 of the height of the sintered bed layer, ventilation will tend to be excessive, and air may flow too much in the ventilation grooves, which may cause uneven burning. . Therefore,
It is most effective to form the ventilation groove in the range from the pallet floor surface to 2/3 of the height of the raw material bed layer.

Further, since iron scrapers are provided on both sides of the disk forming the ventilation groove to remove the adhering raw material,
A long-term stable operation was achieved without the need to manually remove adhering raw materials.

On the other hand, when the ventilation groove is formed by using the round bar, the air permeability, the production rate, the basic unit, and the occurrence rate of the returned ore are improved as compared with the case where the ventilation groove is not provided. Compared with the case of using a plate, the ventilation rod is inferior in air permeability because it only scrapes the raw material and the formation of the ventilation groove is unstable. In addition, the poor air permeability means that the gas flow is not uniform, the uneven burning due to this has not been eliminated, and the occurrence rate of returned ore is higher than that of the disc type.

Example 2 Using the raw materials having the compositions shown in Table 3, the productivity when the sinter was produced under the operating conditions shown in Table 2, the air permeability during the sinter, and the obtained sinter. The result of having investigated about quality is shown in FIG.

[0036]

[Table 3]

In this embodiment, as shown in FIGS. 3 to 5, the rotary shaft having 25 discs (thickness: 20 mm and diameter: 600 mm) fixed at 200 mm intervals in the pallet width direction is provided with a reduction gear motor. While rotating with, insert a disk into the raw material deposition layer and change the height from the pallet floor surface at each position of 50, 100 and 150 mm (hereinafter referred to as the ventilation groove height) within the range of 50 to 300 mm. Formed ventilation grooves. All the formed ventilation grooves had a substantially constant shape, and the ventilation grooves did not collapse with the movement of the pallet.

As is apparent from FIG. 7, by forming the ventilation groove in the lower layer region of the sintering raw material layer, which is not broken by the movement of the pallet, the drop strength and the yield are not adversely affected, and the productivity is improved. As a result, the energy intensity has improved significantly. In particular, the tendency of the yield reduction at the time of 50% compounding based on the high crystal water ore compounding rate of 0%, which was inevitable in the past, was almost improved.

In other words, the high crystal water ore is porous, and the crystal water is dehydrated by heating to increase the porosity after heating, and the reaction interfacial area with the initial melt increases, so that it rapidly increases in a short time. Produces a unique melt. For this reason, conventionally, the through pores that distribute the air to the lower layer are blocked and the uneven burning is increased. On the other hand, according to the present invention, since the ventilation groove for surely ventilating is formed, the air circulation path is facilitated and uneven burning can be prevented.

[0040]

EFFECTS OF THE INVENTION According to the present invention, a ventilation groove is formed in the lower layer region which obstructs the gas permeability and gas flow of the raw material bed in accordance with the circumstances of the raw material, and the gas permeability and gas flow of this lower layer region are greatly increased. The productivity can be improved without deteriorating the quality.

Further, even when a large change in operating conditions, which is represented by using a high crystal water ore as a raw material ore, appropriate aeration and gas flow can be maintained, and operation can be performed while maintaining high productivity. It is possible to deal with changes in conditions quickly and flexibly. Furthermore, there is an advantage that energy efficiency can be improved by reducing the basic unit of coke, the basic unit of electric power, etc. Moreover, it can be carried out only by installing a simple equipment on the existing sintering machine, which greatly improves the efficiency of the production of sinter. It contributes.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a Dwightroid-type sintering machine.

FIG. 2 is a schematic view showing a state of a raw material layer in a sintering process.

FIG. 3 is a schematic view showing a raw material charging device according to the present invention.

FIG. 4 is a schematic diagram showing the operation of the disc in the raw material charging device according to the present invention.

FIG. 5 is a schematic view showing a raw material charging device.

FIG. 6 is a graph showing operation results.

FIG. 7 is a graph showing operation results.

[Explanation of symbols]

 1 Pallet 2 Bedding hopper 3 Bedding sinter 4 Surge hopper 5 Raw material 5a Slope 5b Raw material bed 6 Drum feeder 7 Sloping chute 8 Cut plate 9 Ignition furnace 10 Rotating shaft 11 Disc 12 Ventilation groove 13 Scraper 14 Frame 15 Bracket 16 Motor with reducer 17 chain

Claims (6)

[Claims] 1. In a Dwightroid-type sintering machine, on a floor of a pallet that moves from a raw material supply step to a sintering step,
First, the bedding sinter supplied from the bedding hopper is spread, and then the raw material is charged on the bedding sinter from the raw material surge hopper to form a deposited layer of the raw material. A plurality of plate-like bodies arranged at intervals in the pallet width direction are inserted into the slope while rotating, and a plurality of ventilation grooves are cut and formed in the slope, and then the raw material deposition layer is sintered. Method for producing sintered ore. 2. The method for producing a sintered ore according to claim 1, further comprising removing a raw material adhering to the plate-shaped body. 3. The manufacturing method according to claim 1, wherein the ventilation groove is formed in a range from the floor surface of the pallet to 2/3 of the height of the raw material bed. 4. The raw material contains a highly crystalline water ore,
The manufacturing method according to claim 1. 5. In a Dwightroid-type sintering machine, a pallet filled with bedding sinter supplied from a bedding hopper is spread on a pallet through a surge hopper, a drum feeder, a sloping chute and a cut plate. In the raw material charging device for depositing, a rotary shaft extending in the pallet width direction is installed near the slope of the floor hopper side of the raw material deposit layer so as to be movable in the pallet advancing direction and the raw material depositing direction. A raw material charging device for a Dwightroid-type sintering machine, which is formed by fixing a plurality of plate-shaped bodies. 6. The raw material charging device according to claim 5, wherein the plate-shaped body has a scraper for scraping off the raw material attached thereto.