JP2022182574A - Manufacturing method of sintered ore - Google Patents

Abstract

To provide a manufacturing method of a sintered ore capable of preventing uneven burning of a sintered ore and capable of improving strength and yield of the sintered ore.SOLUTION: A method for manufacturing sintered ore for obtaining a sintered ore by sintering a sintering raw material charged on a pallet of a sintering machine, comprises: a step of inserting a sintering raw material on a pallet of an insertion portion of a sintering machine to deposit to form a raw material layer; a step of leveling an upper surface of the raw material layer; a step of sintering a sintering raw material by igniting on a surface of the levelled raw material layer; and a step of discharging sintered ore after sintering, in which a height of the upper surface of the sintering ore layer before discharging is measured to obtain a sintered ore layer thickness distribution in a horizontal width direction orthogonal to a direction of travel of the raw material layer, and a charging amount of the sintering raw material in the insertion portion is adjusted such that an obtained variation of the sintering ore layer thickness distribution before discharging becomes small.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a method for producing sintered ore with good properties by controlling the charging state of sintering raw materials charged on a pallet of a sintering machine.

FIG. 1 is a diagram showing an example of a sintering machine used in the method for producing sintered ore according to the present invention. In general, sintered ore used as a main raw material in the blast furnace ironmaking process is produced through the steps shown in FIG. The manufacturing method will be briefly described below according to the illustrated flow.

As shown in FIG. 1, iron ore powder with an average particle size of about 1.0 to 5.0 mm, recovered powder in steel works, sintered ore under-sieving powder, CaO-containing raw materials (CaO-based auxiliary raw materials) such as limestone and dolomite, quicklime First, sintering raw materials including granulation aids such as coke powder and coagulants such as anthracite are stored in hoppers 1, respectively. Then, these raw materials are cut out from the hopper 1 containing them in a predetermined ratio onto a conveyor, mixed by a drum mixer 2 for mixing and granulating, moisture is adjusted by adding an appropriate amount of water, and granulated. granulated particles (pseudo-particles) having an average diameter of 3.0 to 6.0 mm. Next, the granulated particles are fed from a surge hopper 4 placed on the sintering machine through a drum feeder 5 and a cutting chute 6 onto an endless movable sintering machine pallet 7 to form a raw material layer of about 400 to 600 mm. The raw material layer 8 is formed by charging so as to have a thickness (height). Next, the coagulant on the upper surface of the raw material layer 8 is ignited by the ignition furnace 9 installed above the raw material layer 8 . By sucking air from a wind box 10 arranged under the sintering machine pallet 7, the coagulant (inner coagulant) in the granulated particles in the raw material layer 8 is burned sequentially from the upper layer to the lower layer. The combustion heat generated at this time heats and melts the granulated sintering raw material, thereby promoting bonding between the raw materials to form a sintered ore. The sintered layer (sintered cake) fired on the sintering machine pallet is conveyed to the next process through the ore discharge section 11 arranged behind the sintering machine, crushed and sized to 5.0 mm The above is collected as product sintered ore. In addition, 3 is a bedding hopper, and 17 is a cut-off gate.

Here, the thickness of the raw material layer 8 is greatly related to the air permeability of the raw material charged layer (sintering bed) at the time of sintering. Therefore, a larger amount of air flows in the portion where the thickness of the raw material layer is smaller than in other portions. That is, the firing air volume is increased. Since a large amount of oxygen is supplied to such a portion where the firing air volume is large, the burning of the coagulant is accelerated, the burning rate increases, and the firing progresses quickly.

In addition, if there is a portion in the raw material layer 8 where the firing air volume is excessively large, only the combustion zone progresses rapidly without being able to maintain a high temperature state due to the burning of the coagulant in that portion, resulting in a structure after firing. becomes brittle and the yield of the product decreases. Furthermore, if the sintering air volume increases, the sintering itself will not propagate, and an unsintered area will remain in the sintering bed, resulting in a decrease in productivity. Note that the combustion zone is a portion of the raw material layer 8 after ignition where the coagulant is burning. Since the cohesive material in the raw material layer is sequentially burned from the upper layer to the lower layer, the combustion zone also moves from the upper layer to the lower layer as the firing progresses.

In addition, when the thickness of the raw material layer fluctuates and the firing rate in the horizontal width direction (hereinafter referred to as "width direction") perpendicular to the direction of movement of the raw material layer is different, the part with the slowest firing rate is used as a reference. In order to consider the completion of sintering, slow down the sintering machine pallet speed to lower the production rate, or discharge a part of the ore from the sintering machine pallet without sintering to increase the sintered ore powder. It will be operated while reducing the product yield, and in any case, it will lead to a reduction in the production rate. The firing rate is the thickness of the raw material layer divided by the time from when the coagulant on the upper surface of the raw material layer is ignited until the combustion zone reaches the lowest end of the raw material layer.

Therefore, in order to improve the product yield, reduce the amount of sintered ore sieved, and reduce the coagulant unit consumption, it is desirable to keep the firing rate constant in the width direction. For this purpose, it is necessary to accurately grasp the raw material layer thickness distribution in the width direction of the raw material layer on the sintering machine pallet so that the raw material layer thickness distribution is constant in the width direction.

Conventionally, as a technique for measuring the thickness of the raw material layer of the raw material charging layer on the sintering machine pallet, a plurality of level gauges were installed in the width direction on the raw material feeding side and the ignition furnace outlet side, and By measuring the moving average values of the raw material layer thickness of the ore section, the raw material layer thickness at the exit side of the ignition furnace, and the pressure under the ignition furnace, and obtaining the split gate opening standard value from these measurement results, the sintering at the entrance side of the sintering machine There is a proposal for a sintering raw material layer thickness control method and apparatus for a sintering machine that appropriately controls the raw material charging layer thickness and makes the raw material layer thickness on the discharge side of the ignition furnace constant in the width direction (for example, Patent Document 1 reference.).

Japanese Patent Application Laid-Open No. 2021-140686

In the sintering machine, the shrinkage behavior of the sintered ore on the pallet continues until the firing is completed, but the shrinkage is not constant, and the amount of shrinkage changes over time depending on the type of ore. I know that. Therefore, it can be seen that the raw material layer thickness on the pallet continues to fluctuate until the firing is completed.

Here, in the sintering raw material layer thickness level control method for a sintering machine described in Patent Document 1, the raw material layer thickness at the ore feeding section and the raw material layer thickness at the discharge side of the ignition furnace are measured. However, the exit side of the ignition furnace is a place where the pallet of the sintering machine reaches about 5 minutes after the start of firing. Generally, sintering takes about 30 minutes, and in the sintering raw material layer thickness level control method for a sintering machine described in Patent Document 1, the raw material layer thickness is measured only at the initial stage of sintering. However, since the raw material layer thickness after the initial stage of sintering cannot be accurately known (cannot be measured), there is an unsolved problem that this causes uneven burning of the sintered ore.

An object of the present invention is to propose a method for producing sintered ore that can prevent uneven burning of sintered ore and improve the strength and yield of sintered ore.

In the course of research to solve the problems of the above-mentioned conventional technology and to achieve the above-mentioned purpose, the inventors found that a plurality of level gauges installed in the width direction in the ore discharge section, which is the firing completion point, By measuring the raw material layer thickness at each position in the width direction, the raw material layer thickness at the end of firing, which is the rate-limiting sintering machine pallet speed, is measured. By equalizing the firing air volume and the firing rate, it is possible to prevent uneven burning and improve the strength and yield of the sintered ore.

That is, the present invention is a sintered ore production method for obtaining sintered ore by sintering sintering raw materials charged on a pallet of a sintering machine, wherein a step of charging and depositing a sintering raw material to form a raw material layer; a step of leveling the upper surface of the raw material layer; In a method for producing sintered ore, the height of the top surface of the sintered ore layer before discharging is measured, and the horizontal width perpendicular to the direction of movement of the raw material layer is measured. The sintered ore layer thickness distribution in the direction is obtained, and the charging amount of the sintering raw material in the charging section is adjusted so that the variation in the obtained sintered ore layer thickness distribution before the ore discharge is reduced. A method for producing sintered ore.

In addition, in the method for producing sintered ore according to the present invention configured as described above,
(1) The sintering raw material is charged onto the pallet of the charging section of the sintering machine from a feeder having a plurality of sub-gates arranged in the horizontal width direction perpendicular to the advancing direction of the raw material layer. Adjusting the charging amount of the sintering raw material in the inlet section by adjusting the opening degrees of the plurality of sub-gates;
(2) In the sintered ore layer thickness distribution before the ore discharge, the amount of sintering raw material charged is increased in the portion where the sintered ore layer is thin, and the sintering raw material is charged in the portion where the sintered ore layer is thick. Adjusting a plurality of sub-gate openings in the charging section so as to reduce the charging amount;
is considered to be a more preferable solution.

According to the present invention, the raw material layer thickness in the width direction of the sintered ore surface on the sintering machine pallet of the ore discharge section is continuously detected, the deviation of each raw material layer thickness in the width direction is obtained, and the deviation is reduced. By the step of adjusting the opening degree of the sub-gate in the charging section, the sintering rate can be accurately controlled to an appropriate state, and high-strength and high-quality sintered ore can be produced with a high yield.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating an example of the conventional sintering machine for which the manufacturing method of the sintered ore which concerns on this invention is object. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating one Embodiment of the sintering machine which enforces the manufacturing method of the sintered ore which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating one Embodiment of the thickness detection apparatus of the raw material layer in the sintering machine which enforces the manufacturing method of the sintered ore which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the concrete structure of the sintering machine which enforces the manufacturing method of the sintered ore which concerns on this invention. It is a figure for demonstrating the thickness detection method of the specific raw material layer of the sintering machine which enforces the manufacturing method of the sintered ore which concerns on this invention.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of the manufacturing method of the sintered ore which concerns on this invention is described, referring drawings.

FIG. 2 is a diagram for explaining an embodiment of a sintering machine that carries out the method for producing sintered ore according to the present invention. In the example shown in FIG. 2, the same members as in the example of the conventional sintering machine shown in FIG. The example shown in FIG. 2 is different from the conventional sintering machine shown in FIG. is provided.

In the sintering machine shown in FIG. 2, a sintered ore is obtained by sintering a sintering raw material 8 charged on a pallet 7 of the sintering machine. Then, the method for producing sintered ore of the present invention is: charging the sintering raw material onto the pallet 7 of the charging section of the sintering machine from the surge hopper 4 having a subgate and the drum feeder 5 disposed thereafter. a step of leveling the upper surface of the raw material layer 8 with a cut-off gate 17; and a step of discharging the sintered ore after sintering from the ore discharging section 11 . In the sintering machine shown in FIG. 2, the feature of the present invention is: In the ore discharge section 11, the height of the upper surface of the sintered ore layer before ore discharge is measured by the thickness detection device 21 disposed in the ore discharge section 11. Then, the sintered ore layer thickness distribution in the horizontal width direction perpendicular to the advancing direction of the raw material layer is obtained, and the amount of sintered raw material in the charging section is adjusted so that the obtained sintered ore layer thickness distribution before exhaust ore discharge is reduced. It is to adjust the charging amount.

In the method for producing sintered ore of the present invention described above, the sintering raw material is charged onto the pallet 7 of the charging section of the sintering machine in the horizontal width direction orthogonal to the traveling direction of the raw material layer 8. It is a preferred mode to start from the feeder 5 having a plurality of sub-gates and adjust the charging amount of the sintering raw material in the charging section by adjusting the opening degrees of the plurality of sub-gates. Further, in the method for producing sintered ore of the present invention described above, in the sintered ore layer thickness distribution before ore discharge, the amount of sintering raw material charged is increased in the portion where the thickness of the sintered ore layer is low, and sintering is performed. It is preferable to adjust the opening degrees of a plurality of subgates in the charging section so that the charging amount of the sintering raw material is reduced in the portion where the thickness of the ore layer is high.

FIG. 3 is a diagram for explaining an embodiment of a raw material layer thickness detection device in a sintering machine that carries out the method for producing sintered ore according to the present invention. In the thickness detection device 21, an example of which is shown in FIG. A laser rangefinder 12 is used. A laser beam 13 is emitted vertically downward from a laser rangefinder 12, and the thickness of the raw material layer 8 charged onto the pallet 7 of the sintering machine is continuously measured from the intensity of the reflected laser beam 13. do. In the present invention, the thickness detection device 21 is arranged in the ore discharge section 11 of the sintering machine, and can measure the thickness of the sintered ore at the completion of sintering. This thickness detection device 21 is carried out at a position where the thickness can be measured on the upstream side from the position where the sintered ore is discharged in the ore discharge section of the sintering machine, but the measurement is performed at a position where the raw material layer is sufficiently sintered to the bottom. There is a need to do. Specifically, it is preferable to measure within a range of about 5 m upstream from the position where the sintered ore is discharged.

FIG. 4 is a diagram for explaining a specific configuration of a sintering machine for carrying out the method for producing sintered ore according to the present invention. The example shown in FIG. 4 shows the charging portion of the sintering raw material 19 and the ore discharging portion 11 of the sintered ore on the entrance side of the sintering machine. It is conveyed in the direction of arrow 14 in the figure). A direction orthogonal to the conveying direction 14 is defined as a width direction 15 of the sintering machine (direction of arrow 15 in the figure). The sintering raw material 19 cut out from the surge hopper 4 is spread and charged onto the pallet 7 of the sintering machine by the drum feeder 5 . A plurality of sub-gates 16 are arranged at equal intervals along the width direction 15 of the sintering machine at the charging portion of the drum feeder 5, and each gate is operated by a command from a control device (arithmetic device) (not shown). By adjusting the degree of opening, it is possible to increase or decrease the cut amount of the sintering raw material 19 at the corresponding portion.

A cut-off gate 17 is arranged on the side of the drum feeder 5 in the conveying direction 14 . This cut-off gate 17 is a so-called leveling plate, and is arranged across the width direction 15 of the sintering machine so as to be positioned at the upper end of the raw material layer 8 . The cut-off gate 17 can be vertically adjusted in the height direction from the bottom surface of the pallet 7, and by consolidating the excess portion of the raw material layer 8 of the sintering raw material 19 in the thickness direction, the raw material layer 8 to make the thickness uniform.

An ignition furnace 9 for igniting the sintering raw material 19 is provided on the output side of the cutoff gate 17 . The sintering material 19 is ignited in the ignition furnace 9 and sucked from an air box placed under the pallet 7 by a main exhaust fan (not shown) to start the sintering process.

The thickness of the raw material layer 8 after flattening by the cut-off gate 17 is constant, but since the cut-off gate 17 flattens the raw material by a method of consolidating the raw material, the thickness of the raw material layer 8 before flattening by the cut-off gate 17 is If there is a difference in the width direction, the sintered raw material 19 after leveling will have a porosity variation in the width direction. Since the sintering air volume fluctuates depending on the porosity of the sintering raw material 19, the width-directional deviation of the thickness of the raw material layer 8 before being leveled by the cut-off gate 17 causes the sintering air volume deviation in the width direction. If there is a deviation in the sintering air volume in the width direction, the sintering progresses quickly at a portion where the sintering rate of the sintering raw material 19 is high, and the shrinkage of the raw material layer 8 is promoted, so sintering in the ore discharge portion 11 at that portion Ore layer thickness decreases. In this way, a deviation in the thickness of the sintered ore layer in the ore discharge portion 11 occurs in the width direction.

In this embodiment, as the thickness detection device 21, a total of six layer thickness level sensors 18 (as an example, the laser rangefinder 12 shown in FIG. 2 can be used) are installed in the ore discharge section 11 at regular intervals. It is arranged to measure the thickness of the sintered ore layer at the time of completion of firing. Specifically, as shown in FIG. 5, if the measured values of each layer thickness level sensor 18 are d1 to d6 and the average value of d1 to d6 is D, di (i=1 to 6) is smaller than D. At the points, the burning velocity is faster than the average in the width direction, and at the points where di (i=1 to 6) is larger than D, the burning velocity is slower than the average in the width direction. Therefore, the object of the present invention can be achieved by reducing the standard deviation σd of d1 to d6.

Therefore, in the present embodiment, the opening degree of the sub-gate 16 is adjusted in the charging section based on the measured value of the layer thickness level sensor 18 so that the standard deviation σd of d1 to d6 becomes small. Since the raw material is first compacted by the cut-off gate 17, it is difficult to determine the change amount of the opening of the sub-gate 16 at once. Therefore, first, the thickness of the raw material layer 8 in the corresponding range is adjusted by sub-gate adjustment by the same amount as the sintered ore layer thickness to be adjusted in the ore discharge section 11, and if there is a shortage or excess, additional adjustment is performed as needed. The opening of the subgate 16 may be adjusted manually, or may be equipped with an automatic adjustment function by a machine. Since the amount of shrinkage of the sintering raw material 19 varies depending on the type of mineral, it is preferable to adjust the sub-gate opening degree at the timing when the composition of the sintering raw material 19 used changes.

Using a Dwight Lloyd sintering machine with a daily scale of 8000 tons having the same configuration as the example shown in FIG. , the sintering raw material 19 (iron ore, limestone, return ore, coke fine, etc.) was discharged from the drum feeder 5 . The opening of the subgate 16 was set to a constant opening that does not interfere with daily production activities. The sintering raw material 19 was flattened by the cut-off gate 17 and then ignited by the ignition furnace 9 to be sintered. According to the manufacturing process described above, the following three patterns of control methods were compared.

<Without sub-gate adjustment: conventional example>
By maintaining the opening degree of the sub-gate 16 at the above-mentioned constant opening degree, six layer thickness level sensors 18 (for example, laser rangefinders) arranged in the width direction of the ore discharge section 11 as shown in FIGS. , the distances d1 to d6 to the sintered ore in the ore discharge section 11 were measured. The result at this time was defined as "unadjusted".

<In the case of sub-gate adjustment: Comparative example according to Patent Document 1>
At the outlet point of the ignition furnace 9, the average value D of the distances d1 to d6 to the raw material layer measured by each layer thickness level sensor 18 is calculated, and the difference between each di (i = 1 to 6) and D (D- di) was obtained. The opening of the subgate was adjusted by rotating the rotary handle on the side of the gate. The opening degree of the sub-gate 16 was adjusted in the direction of opening the sub-gate 16 when (D-di) was positive and in the direction of closing the sub-gate 16 when (D-di) was negative. When the sintering raw material 19 discharged from the drum feeder 5 after adjusting the opening degree of the subgate 16 reaches each raw material layer thickness level sensor 18 at the point in front of the ore discharge section 11 as sintered ore, the sintered ore layer d1 to d6 were measured in the width direction. The result at that time was taken as "adjustment of the opening degree of the sub-gate with each raw material layer thickness on the discharge side of the ignition furnace".

<In the case of sub-gate adjustment: Example of the present invention>
At the point before the ore discharge section 11, the average value D of the distances d1 to d6 to the sintered ore measured by each layer thickness level sensor 18 is calculated, and the difference between each di (i = 1 to 6) and D (D -di) was determined. The opening of the subgate was adjusted by rotating the rotary handle on the side of the gate. The opening degree of the sub-gate 16 was adjusted in the direction of opening the sub-gate 16 when (D-di) was positive and in the direction of closing the sub-gate 16 when (D-di) was negative. When the sintering raw material 19 discharged from the drum feeder 5 after adjusting the opening degree of the subgate 16 reaches each raw material layer thickness level sensor 18 at the point in front of the ore discharge section 11 as sintered ore, the sintered ore layer d1 to d6 were measured again in the width direction. The result at that time was defined as "adjustment of the opening of the sub-gate by the thickness of each raw material layer in the ore discharge section."

In the above-described procedure, in the ore discharge section 11, the distance d1 to d6 (in the case of “unadjusted”) to the sintered ore before subgate adjustment (same after adjustment because subgate adjustment is not performed), sintered ore after subgate adjustment From the distances d1 to d6 to coalescence (in the case of ``adjustment of subgate opening with each raw material layer thickness on the discharge side of the ignition furnace'' and ``adjustment of subgate opening with each raw material layer thickness at the discharge section''), respectively, σd of the distance to the sinter after subgate adjustment was calculated. Moreover, the shutter strength of the sintered ore and the yield of the sintered ore were measured. The shutter strength of the sintered ore was determined according to JIS M 8711. The yield of the sintered ore was calculated from "the weight on the sieve/the weight of the base material" when the sintered ore after the ore discharge was sieved through a sieve mesh with a sieve mesh of 5×15 mm. The results are shown in Table 1 below.

From the results in Table 1, σd of the distance to the sintered ore, the shutter strength of the sintered ore, and the yield of the sintered ore are all "unadjusted" < "the opening degree of the subgate is adjusted at each raw material layer thickness on the exit side of the ignition furnace. ”<“Adjustment of opening degree of sub-gate with each material layer thickness of ore discharge section”. From this, by changing the sub-gate opening degree based on the height of each sintered ore in front of the ore discharge section, the firing rate can be accurately controlled to an appropriate state, and high-strength and high-quality sintered ore can be obtained. can be produced with high yield.

The method for producing sintered ore according to the present invention is used for sintering raw materials obtained from various formulations, especially when aiming to prevent uneven burning of sintered ore and to improve the strength and yield of sintered ore. Suitable application is possible.

1 Hopper 2 Drum Mixer 3 Bedding 4 Surge Hopper 5 Drum Feeder 6 Cutting Chute 7 Pallet 8 Raw Material Layer 9 Ignition Furnace 10 Wind Box 11 Ore Discharge Section 12 Laser Rangefinder 13 Laser Light 14 Conveying Direction 15 Width Direction 16 Subgate 17 Cut Off gate 18 Raw material layer thickness level sensor 19 Sintered raw material 21 Thickness detector

Claims (3)

A sintered ore production method for obtaining sintered ore by sintering a sintered raw material charged onto a pallet of a sintering machine, wherein the sintered raw material is charged onto the pallet of the charging section of the sintering machine. forming a raw material layer by depositing, smoothing the upper surface of the raw material layer, igniting the surface of the smoothed raw material layer to sinter the sintering raw material, and sintered sintered ore and a method for producing sintered ore comprising
Measure the height of the upper surface of the sintered ore layer before ore discharge, obtain the sintered ore layer thickness distribution in the horizontal width direction perpendicular to the direction of movement of the raw material layer, and obtain the dispersion of the obtained sintered ore layer thickness distribution before ore discharge. A method for producing sintered ore, characterized in that the charging amount of the sintering raw material in the charging section is adjusted so that the is small. The sintering raw material is charged onto the pallet of the charging section of the sintering machine from a feeder having a plurality of sub-gates arranged in the horizontal width direction orthogonal to the direction of movement of the raw material layer. 2. The method for producing sintered ore according to claim 1, wherein the charging amount of the sintering raw material is adjusted by adjusting the opening degrees of the plurality of subgates. In the sintered ore layer thickness distribution before the ore discharge, the amount of sintering raw material charged is increased in the portion where the sintered ore layer is thin, and the amount of sintered raw material charged is increased in the portion where the sintered ore layer is thick. 3. The method for producing sintered ore according to claim 2, wherein a plurality of subgate opening degrees in the charging section are adjusted so as to reduce the

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