Sintered ore manufacturing method and sintering machine

Abstract

To accurately measure sintering of a carbonaceous material in an insertion layer and the melting progress situation of a sintering raw material and to optimize the sintering of the carbonaceous material and the melting progress situation of the sintering raw material if necessary when a sintered ore is produced.SOLUTION: A sintered ore production method comprises: inserting a sintering raw material into a circulating pallet 26 to form an insertion layer; igniting the upper surface layer of the insertion layer using an ignition furnace 20; sucking air from below the insertion layer to sinter a carbonaceous material contained in the sintering raw material and form sintered cake; and then discharging the sintered cake to produce a sintered ore. A contraction amount or a contraction speed of the insertion layer after the ignition is measured, and an initial packing density of the insertion layer is adjusted so that the contraction amount or the contraction speed of the insertion layer can be within a prescribed range.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing sintered ore, which is a raw material for a blast furnace, and a sintering machine for producing sintered ore. [Background technology]

[0002] Sintered ore, which is a raw material for blast furnaces, is generally produced using iron-containing raw materials such as iron ore powder, recovered powder in a steelworks, and sintered ore undersize powder, CaO-containing raw materials such as limestone and dolomite, and carbonaceous materials (solid fuel) such as coke fines and anthracite, using a Dwight Lloyd sintering machine (hereinafter referred to as a "sintering machine"), which is an endless traveling sintering machine.

[0003] The sintering raw materials are loaded onto the sinter machine's endless moving pallet to form a sintering bed. The thickness (height) of the sintering bed is approximately 400 to 800 mm. The carbonaceous material in the sintering bed is then ignited by an ignition furnace installed above the sintering bed. Air is drawn downward through a wind box installed below the pallet, causing the carbonaceous material in the sintering bed to combust. This combustion progresses gradually downward and forward as the pallet moves. The combustion heat generated during this process burns and melts the sintering raw materials, producing a sinter cake. The resulting sinter cake is then crushed in the discharge section, cooled in a cooler, and sized to produce the finished sintered ore.

[0004] In the above-mentioned sintering machine, from the viewpoint of improving the strength and yield of sintered ore, it is important to grasp and optimize the progress of the combustion of carbonaceous material and the melting of sinter raw materials in the sintering bed. For example, Patent Document 1 discloses a temperature measuring device that protrudes from the bottom of a pallet and has two or more temperature measuring parts for the purpose of measuring the temperature and sintering rate in the sintering bed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-243443 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned conventional techniques have the following problems.

[0007] That is, in Patent Document 1, the temperature in the sintering bed is measured by a temperature measuring device, but the temperature in the sintering bed decreases regardless of the progress of combustion of the carbonaceous material and melting of the sintering raw materials due to disturbance factors such as local voids generated in the sintering bed or excessive air intake through the boundary between the sintering bed and the pallet. Therefore, the temperature in the sintering bed does not necessarily reflect only the progress of combustion of the carbonaceous material and melting of the sintering raw materials in the sintering bed, and there is a problem that the temperature in the sintering bed has a large error when used as an indicator of the progress of combustion of the carbonaceous material and melting of the sintering raw materials.

[0008] The present invention has been made in view of the above problems, and its object is to provide a method for producing sintered ore and a sintering machine that can accurately measure the progress of combustion of carbonaceous material and melting of sintering raw materials in a sintering bed when producing sintered ore, and can optimize the progress of combustion of carbonaceous material and melting of sintering raw materials as needed. [Means for solving the problem]

[0009] The gist of the present invention for solving the above problems is as follows.

[0010] [1] A method for producing sintered ore, which comprises charging raw materials onto a circulating pallet to form a charging layer, igniting the upper surface of the charging layer using an ignition furnace, drawing air from below the charging layer to combust the carbonaceous material contained in the sintered raw materials and form a sinter cake, and then discharging the sinter cake from a discharge section to produce sintered ore, characterized in that the amount of shrinkage of the charging layer after ignition is measured, and the initial packing density of the charging layer is adjusted so that the amount of shrinkage of the charging layer is within a predetermined range.

[0011] [2] A method for producing sintered ore, which comprises charging sintering raw materials onto a circulating pallet to form a charging layer, igniting the upper surface of the charging layer using an ignition furnace, drawing air from below the charging layer to combust the carbonaceous material contained in the sintering raw materials and form a sintered cake, and then discharging the sintered cake from a discharge section to produce sintered ore, characterized in that the shrinkage rate of the charging layer after ignition is measured, and the initial packing density of the charging layer is adjusted so that the shrinkage rate of the charging layer is within a predetermined range.

[0012] [3] The method for producing sintered ore according to [1], characterized in that the measurement is performed at two or more locations in the width direction of the pallet, and the initial packing density of the sintered ore bed is adjusted in the width direction of the pallet.

[0013] [4] The method for producing sintered ore according to [2], characterized in that the measurement is performed at two or more locations in the width direction of the pallet, and the initial packing density of the sintered ore bed is adjusted in the width direction of the pallet.

[0014] [5] The method for producing sintered ore according to [1], characterized in that the measurement is performed at two or more locations in the direction of movement of the pallet.

[0015] [6] The method for producing sintered ore according to [2], characterized in that the measurement is performed at two or more locations in the direction of movement of the pallet.

[0016] [7] The method for producing sintered ore according to [3], characterized in that the measurement is performed at two or more locations in the direction of movement of the pallet.

[0017] [8] The method for producing sintered ore according to [4], characterized in that the measurement is performed at two or more locations in the direction of movement of the pallet.

[0018] [9] The method for producing sintered ore according to any one of [1] to [8], wherein the measurement is performed by measuring the height position of the upper surface of the sintering bed.

[0019]

[10] The method for producing sintered ore according to [9], characterized in that the measurement is performed without contacting the sintering bed.

[0020]

[11] A sintering machine comprising a circulating pallet, a feeding section for charging sintering raw materials onto the pallet to form a sintering layer, an ignition furnace for igniting the carbonaceous material on the surface of the sintering layer, and a wind box installed below the pallet for drawing air from below the sintering layer, and sintering the sintering raw materials using the combustion heat of the carbonaceous material contained in the sintering raw materials, characterized in that it has a position measuring device for measuring the amount of shrinkage of the sintering layer after ignition and has the function of adjusting the initial packing density of the sintering layer so that the amount of shrinkage of the sintering layer is within a predetermined range.

[0021]

[12] A sintering machine comprising a circulating pallet, a feeding section for charging sintering raw materials onto the pallet to form a sintering layer, an ignition furnace for igniting the carbonaceous material on the surface of the sintering layer, and a wind box installed below the pallet for drawing air from below the sintering layer, and sintering the sintering raw materials using the combustion heat of the carbonaceous material contained in the sintering raw materials, characterized in that it has a position measuring device for measuring the shrinkage rate of the sintering layer after ignition and has the function of adjusting the initial packing density of the sintering layer so that the shrinkage rate of the sintering layer is within a predetermined range.

[0022]

[13] The sintering machine described in

[11] , characterized in that the position measuring device has the function of measuring two or more locations in the width direction of the pallet and adjusting the initial packing density of the sintering layer in the width direction of the pallet.

[0023]

[14] The sintering machine described in

[12] , characterized in that the position measuring device has the function of measuring two or more locations in the width direction of the pallet and adjusting the initial packing density of the sintering layer in the width direction of the pallet.

[0024]

[15] The sintering machine according to

[11] , characterized in that the position measuring device measures at least two positions in the direction of pallet movement.

[0025]

[16] The sintering machine according to

[12] , characterized in that the position measuring device measures at least two positions in the direction of pallet movement.

[0026]

[17] The sintering machine according to

[13] , characterized in that the position measuring device measures at least two positions in the direction of movement of the pallet.

[0027]

[18] The sintering machine according to

[14] , characterized in that the position measuring device measures at least two positions in the direction of movement of the pallet.

[0028]

[19] A sintering machine according to any one of

[11] to

[18] , characterized in that the position measuring device measures the height position of the upper surface of the sintering bed.

[0029]

[20] The sintering machine according to

[19] , characterized in that the position measuring device measures without contacting the sintering bed. [Effects of the Invention]

[0030] According to the present invention, the amount or rate of shrinkage of the sintering raw material loading layer during sintering is measured, so that the progress of combustion of the carbonaceous material and melting of the sintering raw material in the loading layer can be measured with high accuracy, and the progress of combustion of the carbonaceous material and melting of the sintering raw material can be optimized as necessary. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a side view showing a schematic diagram of an example of a sintering machine used when carrying out a method for producing sintered ore according to the present invention. FIG. [Figure 2] FIG. 2 is a perspective schematic view of the sintering machine shown in FIG. [Figure 3] FIG. 10 is a diagram showing the results of investigating the behavior of the shrinkage amount of the sintering bed during sintering by changing the initial packing density of the sintering bed. [Figure 4] FIG. 10 is a diagram showing the results of investigating the amount of shrinkage of the sintering bed during sintering by changing the initial packing density of the sintering bed. [Figure 5]FIG. 10 is a diagram showing the results of investigating the yield of sintered ore after sintering by changing the initial packing density of the sintering bed. [Figure 6] FIG. 10 is a diagram showing the results of investigating the sintering time by changing the initial packing density of the sintering bed. [Figure 7] FIG. 10 is a diagram showing the results of investigating the production efficiency of a sinter machine by changing the initial packing density of the sintering bed. [Figure 8] FIG. 1 is a diagram showing the results of investigating TI strength by changing the initial packing density of the sintering bed. [Figure 9] FIG. 10 is a diagram showing the results of investigating the amount of shrinkage of the sintering bed during sintering by changing the initial packing density of the sintering bed. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a side view showing an example of a sintering machine 10 used when carrying out a method for producing sintered ore according to the present invention. Fig. 2 is a perspective view showing the sintering machine 10 shown in Fig. 1.

[0033] Sintering raw materials, which include iron-containing raw materials such as iron ore powder, recovered powder from the steelworks, and sintered ore undersize powder, CaO-containing raw materials such as limestone and dolomite, and carbonaceous materials (solid fuel) such as coke fines and anthracite, are fed by a roll feeder 14 from a surge hopper 12 provided in the ore feeding section 40 of the sintering machine 10, and are charged onto an endless moving pallet 26 that moves in a circular motion while being guided by the slope of a charging chute 15, forming a charging layer of the sintering raw materials inside the pallet 26. At this time, the thickness (height) of the charging layer is controlled by adjusting the opening of a plurality of dividing gates 16 installed below the surge hopper 12 along the width direction of the pallet 26.

[0034] In this embodiment, the dividing gate 16 is divided into, for example, eight gates as shown in Fig. 2, and each dividing gate 16 is assigned a gate number (1 to 8) in accordance with the order of its position in the width direction of the pallet 26. Furthermore, eight magnetic brakes 17 are provided at positions corresponding to the dividing gates 16 of the charging chute 15. The magnetic brakes 17 act on magnetic ores contained in the sintering raw material, thereby slowing down the charging speed of the sintering raw material.

[0035] The charging layer formed on the pallet 26 moves toward the downstream side of the sinter machine 10 together with the pallet 26. A level meter 18 is provided downstream of the dividing gate 16. Eight level meter 18 are provided, the same number as the number of dividing gates 16, one provided downstream of each dividing gate 16. Each level meter 18 is assigned the same number as the dividing gate number, and each level meter 18 measures the thickness of the charging layer of the dividing gate 16 assigned the same number. In this embodiment, an ultrasonic level meter is used as the level meter 18.

[0036] Each level meter 18 measures the thickness of the charging layer and outputs the measured thickness data to the control device 32. Based on the input thickness data, the control device 32 controls the opening degree of each dividing gate 16 so that the thickness of the charging layer becomes uniform in the width direction of the pallet 26 or becomes a specified thickness.

[0037] The upper surface of the sintering bed is ignited by the ignition furnace 20 installed downstream of the ore supply section 40. Furthermore, air is sucked in by the blower 24, and the air in the sintering bed is sucked downward through a plurality of wind boxes 22 installed below the pallets 26 in the machine longitudinal direction, while air is introduced into the sintering bed from above, causing the carbonaceous material contained in the sintering raw materials to combust. The amount of air sucked in can be adjusted by adjusting the rotation speed of the blower 24.

[0038] The sinter raw materials are baked and hardened by the heat of combustion of the carbonaceous material to form a sinter cake, which is a lump of sintered ore. The sinter cake is discharged from the ore discharge section 42. The sinter cake discharged from the ore discharge section 42 cracks in the width direction of the pallet 26 and breaks just before falling from the pallet 26. Red hot spots 38 appear on the fractured surface of the sinter cake left on the pallet 26. The ore discharge section camera 30 captures an image of the red hot spots 38 appearing on the fractured surface of the sinter cake and outputs the captured image data to the control device 32. The control device 32 controls the rotation speed of a drive device (not shown) that moves the pallet 26 according to the input thickness data of the red hot spots 38, and adjusts the moving speed of the pallet 26 to adjust the thickness of the red hot spots 38 within an appropriate range.

[0039] Thereafter, the sintered cake falls from the ore discharge section 42, is crushed, cooled in a cooler (not shown), and sized to become a sintered ore product consisting of agglomerates with a particle size exceeding 5.0 mm, for example.

[0040] The control device 32 has a storage unit 34 and a control unit 36. The control device 32 is, for example, a general-purpose computer such as a workstation or a personal computer. The storage unit 34 is, for example, an updatable flash memory, a built-in hard disk or a hard disk connected via a data communication terminal, an information recording medium such as a memory card, and a read / write device for the information recording medium. The storage unit 34 pre-stores programs necessary for implementing the sinter ore manufacturing method according to this embodiment, as well as data used during execution of the programs. The control unit 36 ​​is, for example, a CPU, and controls the operation of the sinter machine 10 using the programs and data stored in the storage unit 34.

[0041] After ignition, the temperature of the sintering raw materials rises and melts due to the combustion of carbonaceous materials in the sintering bed, progressing from the top to the bottom. It is known that the sintering bed shrinks during this sintering process. Although the shrinkage progresses in all directions, due to the influence of the weight of the sintering bed, most of the shrinkage is observed as a decrease in the height of the top surface of the sintering bed.

[0042] The present inventors have observed the shrinkage behavior by measuring the height position of the upper surface of the sintering bed while changing the sintering conditions, and have obtained the following findings.

[0043] (1) The shrinkage rate of the sintering bed increases with the amount of carbonaceous material, reaching 10-20% at the optimal carbonaceous material content (4.0-4.4% by mass) where the sintering reaction proceeds without excess or deficiency. When the carbonaceous material content is increased by 1% by mass near the optimal carbonaceous material content, the shrinkage rate of the sintering bed increases by more than 7%, a change of more than seven times the carbonaceous material content. This suggests that the shrinkage of the sintering bed is not due to the loss of volume caused by the burning of the carbonaceous material itself, but is largely due to the melting of the sintered layer and the filling of voids. Therefore, it is believed that the shrinkage of the sintering bed accurately reflects the progress of sintering. The amount of carbonaceous material is adjusted by charging sintering raw materials with a predetermined carbonaceous material content into the surge hopper 12 and then loading the sintering raw materials onto the pallet 26.

[0044] (2) The initial packing density of the sintering bed (the packing density when the sintering bed is formed) is set to an appropriate value (1.70 to 1.90 ton / m 3 ), the time from ignition of the sintering bed to the start of contraction becomes longer, and the final contraction amount of the sintering bed becomes smaller. 3 ) is the weight of a substance when it contains water (wet ton) and its volume (m 3 ) is the value divided by

[0045] In Fig. 3, the initial depth of the sintering bed is set to 600 mm, and the initial packing density of the sintering bed is set to 1.76 to 2.07 ton / m 3 The results of investigating the behavior of the shrinkage of the sintering bed during sintering are shown in Fig. 3. As shown in Fig. 3, when the initial packing density of the sintering bed was changed in the range of 1.76 to 1.89 ton / m 3 In the case of , shrinkage of the sintering bed occurs 5 minutes after ignition, but the initial packing density of the sintering bed is 1.98 to 2.07 ton / m 3 In the case of , no significant shrinkage of the sinter bed occurred even after 20 minutes had passed since ignition. 3The final shrinkage was small in the case of . The initial packing density of the sintering bed was adjusted by changing the particle size composition of the sintering raw materials.

[0046] (3) The larger the initial packing density of the sintering bed, the smaller the shrinkage of the sintering bed. 3 Above this level, the shrinkage of the sintering bed is small and the amount of shrinkage may approach zero.

[0047] Figure 4 shows the results of investigating the amount of shrinkage of the sintering bed during sintering by changing the initial packing density of the sintering bed, with the initial depth of the sintering bed set to 600 mm. As shown in Figure 4, the amount of shrinkage of the sintering bed decreased as the initial packing density of the sintering bed increased.

[0048] (4) The yield of product sinter (grain size 5.0 mm or more) is 1.9 ton / m when the initial packing density of the sintered ore bed is 1.9 ton / m 3 When the initial packing density of the sintered bed is less than 2.0 ton / m, the packing density is almost constant. 3 Above this, it decreases slightly.

[0049] Figure 5 shows the results of an investigation into the yield of product sintered ore (particle size 5.0 mm or more) after sintering, with the initial depth of the sintering bed set to 600 mm and the initial packing density of the sintering bed varied. As shown in Figure 5, the initial packing density of the sintering bed had little effect on the yield of product sintered ore, but there was a tendency for the yield of product sintered ore to decrease as the initial packing density of the sintering bed increased.

[0050] (5) If the initial packing density of the sintering bed is large, the sintering time will be extended. As a result, if the initial packing density of the sintering bed is large, the production efficiency of the sintering machine (production efficiency per sintering machine area: ton / (hr × m 2 )) decreases.

[0051] Figure 6 shows the results of investigating the sintering time by changing the initial packing density of the sintering bed, with the initial depth of the sintering bed set to 600 mm. Figure 7 shows the results of investigating the production efficiency of the sinter machine by changing the initial packing density of the sintering bed, with the initial depth of the sintering bed set to 600 mm. As shown in Figure 6, the sintering time increased as the initial packing density of the sintering bed increased. Also, as shown in Figure 7, the production efficiency of the sinter machine decreased as the initial packing density of the sintering bed increased.

[0052] (6) The initial packing density of the sintering bed is 2.0 ton / m 3 Below 2.0 ton / m, the TI strength is almost constant. 3 Above this, the TI strength decreases.

[0053] Figure 8 shows the results of investigating the TI strength by changing the initial packing density of the sintering bed with an initial depth of 600 mm. As shown in Figure 8, when the initial packing density of the sintering bed is 2.0 ton / m 3 Above this, the TI strength decreased. Here, the TI strength is the rotational strength index of sintered ore measured in accordance with JIS M 8712. The TI strength is measured by the following procedures (i) and (ii).

[0054] (i) Using a rotating drum (inner diameter 1000 mm, inner length 500 mm), rotate a 15 kg measurement sample at a speed of 25 rpm ± 1 rpm for a total of 200 rotations.

[0055] (ii) The measurement sample after rotation is sieved through a sieve with a mesh size of 6.3 mm, and the TI strength is calculated as the mass fraction (mass%) of the post-test measurement sample with a particle size of +6.3 mm sieved onto the sieve to the total mass of the pre-test measurement sample.

[0056] From the above findings, it was found that if the initial packing density of the sintering bed is greater than the appropriate range, the production efficiency of the sintering machine 10 will drop significantly, and improvements in the yield and TI strength of the sintered ore product cannot be expected.

[0057] Therefore, if the initial packing density of the sintering bed is excessively large so as to cause a decrease in production efficiency, it is necessary to reduce the initial packing density of the sintering bed to an appropriate value. However, it has been extremely difficult to quickly determine whether the initial packing density of the sintering bed is appropriate during the sintering process.

[0058] Therefore, the present inventors have intensively studied a means for quickly determining whether the initial packing density of the sintering bed is appropriate during the sintering process, and have found that it is possible to estimate whether the initial packing density of the sintering bed is appropriate by measuring the amount or rate of shrinkage of the sintering bed during sintering.

[0059] The inventors set the initial packing density of the sintered bed on the left side of the center of the pallet 26 to 1.76 ton / m on the pallet 26 having a sintered bed width of 800 mm and an initial sintered bed depth of 400 mm. 3 (optimum packing density), and the initial packing density of the sintering layer on the right side from the center is 1.98 ton / m 3 (excessive packing density) (solid line), and the initial packing density of the charging layer across the entire width of the pallet 26 is 1.76 ton / m 3 The amount of shrinkage of the sintering bed during sintering was investigated for the cases where the sintering was performed as normal (dashed line) and normal (dashed line). Figure 9 shows the results of the investigation.

[0060] As shown in Fig. 9, the initial packing density of the sintered bed was 1.98 ton / m 3 In this case, the initial packing density of the sintered bed is 1.76 ton / m 3 The shrinkage of the sintering bed during sintering was smaller than in the case of (1). Therefore, it was found that it is possible to estimate whether the initial packing density of the sintering bed is appropriate by measuring the shrinkage or shrinkage rate of the sintering bed during sintering. In other words, it was found that the decline in the production efficiency of the sintering machine can be suppressed by adjusting the initial packing density of the sintering bed based on the measurement results of the shrinkage behavior of the sintering bed during sintering.

[0061] The present invention has been made based on the above findings, and the sintering machine 10 according to the present invention is provided with a position measuring device 28 for measuring the amount and rate of shrinkage of the sintering bed during sintering. The position measuring device 28 is provided downstream of the ignition furnace 20, and measures the height position of the upper surface layer of the sintering bed as it leaves the ignition furnace 20, and outputs the measured height position data to the control device 32. The control unit 36 ​​of the control device 32 calculates the amount and rate of shrinkage of the sintering bed based on the input height position data.

[0062] <Measurement mechanism of the position measuring device 28> The measurement target of the position measuring device 28 is the outer surface of the sintering bed, which is at a lower temperature than the inside of the sintering bed, where the temperature reaches 1200°C or higher. Therefore, it is also possible to measure the height position of the upper surface of the sintering bed using a contact-type weight or a roller with an arm as the position measuring device 28. However, from the viewpoint of durability, it is preferable that the position measuring device 28 be a non-contact type position measuring device such as an ultrasonic distance meter.

[0063] From the viewpoints of a wide measurement field and measurement depth, high position resolution, a large number of measurement points, and high measurement speed, it is more preferable that the position measurement device 28 be a non-contact optical position measurement device such as a laser scanner. Examples of laser scanners include the Leica ScanStation P series 3D scanner. Many of these achieve high-speed scanning by minute movements of a galvanometer mirror that reflects a laser. However, if they are installed directly above the charging layer and attempt to measure vertically downward, limitations such as reduced measurement accuracy and speed may arise (although there are models that do not encounter limitations, the limitations tend to be greater for models with higher speed and accuracy).

[0064] In such cases, the position measuring device 28 can be installed obliquely above the sintering bed rather than directly above it, and measurements can be taken obliquely downward. The smaller the depression angle (the angle between the line of sight to an object below and the horizontal), the fewer restrictions there are on measurement accuracy and measurement speed. However, if the incident angle of the laser to the top surface of the sintering bed is small, unevenness on the top surface of the sintering bed can create blind spots at the measurement position or reduce the height measurement accuracy. For this reason, it is preferable that the depression angle be 15 degrees or more.

[0065] When measuring over a wide range in the longitudinal direction of the sintering machine 10 (the moving direction of the pallet 26), the depression angle may be insufficient for locations far from the position measuring device 28. In such cases, multiple position measuring devices 28 may be installed.

[0066] <Measurement target position of the position measuring device 28> The purpose of the measurement by the position measuring device 28 is to grasp the shrinkage of the charging layer due to the sintering reaction, so it is necessary to measure downstream of the ignition furnace 20 where the sintering reaction starts. In particular, it is preferable to measure near the ore discharge part 42 where the sintering reaction is considered to have completed or its upstream side (for example, within 2 m from the ore discharge part 42). This makes it possible to grasp the degree of sintering of the sintered cake after sintering.

[0067] Furthermore, it is more preferable to measure at two or more locations: near the discharge section 42 or its upstream side, and further upstream (for example, within 10 to 90% of the path from the ignition furnace 20 to the discharge section 42). By measuring at two or more locations in the direction of movement of the pallet 26, comparison with previous or subsequent measurements allows not only the degree of sintering of the sintered cake after sintering but also the sintering rate during sintering to be determined. Understanding the sintering rate is useful information for preventing excessive sintering, which could inhibit the formation of calcium ferrite phase or reduce strength. Furthermore, by measuring at a location further upstream than near the discharge section 42 or its upstream side, the degree of sintering can be determined more quickly than when measuring near the discharge section 42 or its upstream side, allowing operational action to be taken more quickly to optimize the sintering reaction.

[0068] Furthermore, it is preferable to use the position measuring device 28 to measure two or more positions in the width direction horizontally perpendicular to the moving direction of the pallet 26. In this way, even if there is a difference in the progress of sintering in the width direction of the pallet 26, it can be optimized by adjusting the packing density of the charging layer in the width direction of the pallet 26.

[0069] <Measurement frequency of the position measuring device 28> The measurement frequency of the position measuring device 28 can be effective even if it is limited to low frequency measurements at times when changes in the progress of the sintering reaction are expected, such as when the raw material composition is changed, but by setting the measurement interval to within the time required for the sintering raw material to pass through the entire length of the sintering machine (for example, 20 minutes), and more preferably within 2 minutes, which can be considered as virtually continuous measurement, it is possible to respond to unexpected changes in the composition or particle size of the sintering raw material.

[0070] When the control unit 36 ​​acquires height position data of the upper surface of the sintering bed from the position measuring device 28, it calculates the shrinkage amount and shrinkage rate of the sintering bed from the amount of descent of the upper surface of the sintering bed. If the shrinkage amount or shrinkage rate of the sintering bed is not appropriate, the control unit 36 ​​has a function of issuing an alarm to notify an operator or a function of transmitting a signal to a device controlling the initial packing density of the sintering bed to change the initial packing density of the sintering bed. Upon receiving the signal from the control unit 36, the operator or the device controlling the initial packing density of the sintering bed adjusts the initial packing density of the sintering bed based on a predetermined means, and controls the shrinkage amount or shrinkage rate of the sintering bed within a predetermined range.

[0071] The initial packing density of the sintering bed can also be adjusted by changing the particle size composition of the sintering raw materials, but this requires 30 minutes or more to change the sintering raw material mix and start adjustment, during which time improper operation continues. As a method for quickly adjusting the initial packing density of the sintering bed based on the amount of shrinkage or shrinkage rate of the sintering bed measured during the sintering process, it is preferable to use one or more of the following methods: adjusting the opening of the dividing gate 16, adjusting the angle of the charging chute 15, and adjusting the magnetic force of the magnetic brake 17. By using these methods to adjust the initial packing density of the sintering bed, the time required to start adjustment can be reduced to less than 30 minutes.

[0072] For example, in the case of the dividing gate 16, the initial packing density of the charging bed increases by widening the opening of the dividing gate 16, and decreases by narrowing the opening of the dividing gate 16. In this way, the initial packing density of the charging bed can be adjusted by adjusting the opening of the dividing gate 16.

[0073] In addition, in the charging chute 15, the initial packing density of the charging bed increases by increasing the inclination angle of the charging chute 15 with respect to the horizontal plane, and the initial packing density of the charging bed decreases by decreasing the inclination angle of the charging chute 15 with respect to the horizontal plane. In this way, the initial packing density of the charging bed can be adjusted by adjusting the inclination angle of the charging chute 15.

[0074] In addition, the magnetic brake 17 applies magnetic force to the magnetic ore contained in the sintering raw material to slow down the charging speed of the sintering raw material. This reduces the initial density of the sintering bed. Therefore, the magnetic brake 17 can adjust the initial packing density of the sintering bed by adjusting the distance between the magnet and the charging chute or by adjusting the magnetic force of the magnetic brake 17.

[0075] Furthermore, instead of or in addition to these methods, it is preferable to adjust the initial packing density using ventilation rods. The ventilation rods are rod- or plate-shaped structures that are inserted into the charging layer formed on the pallet 26, and inserting the ventilation rods prevents the initial packing density from becoming too high.

[0076] The thickness of the sintered layer before ignition can be measured by the level meter 18. Furthermore, if a non-contact optical device such as a laser scanner, which has a wide measurement field and can measure a large number of measurement points at high speed, is used as the position measuring device 28, it is possible to measure both the thickness of the sintered layer after ignition and the thickness of the sintered layer before ignition with the same position measuring device.

[0077] Furthermore, when a non-contact optical device such as a laser scanner is used as the position measuring device 28, the upper surface layer from which the height position data has been acquired can be divided into two or more regions in the width direction of the pallet 26, and the average height position in the divided regions can be calculated. For example, when the upper surface layer is divided into two regions in the width direction of the pallet 26, the center of the width direction is used as the boundary, and the average height of the region on the front side and the average height of the region on the back side are calculated.

[0078] As described above, according to the present invention, the shrinkage amount or shrinkage rate of the sintering raw material charging layer during sintering is measured, so that the progress of combustion of the carbonaceous material and melting of the sintering raw material in the charging layer can be measured with high accuracy, and the progress of combustion of the carbonaceous material and melting of the sintering raw material can be optimized as necessary. [Example]

[0079] An example in which sintered ore was produced using the same apparatus as the sintering machine 10 shown in Figures 1 and 2 will be described below. In this example, the opening degree of the charging gate was adjusted in accordance with the amount of shrinkage of the sinter raw material charging layer in four regions (regions 1, 2, 3, and 4) divided in the width direction of the pallet 26 (Example 1 of the present invention). The results of Example 1 of the present invention and Comparative Example 1 in which the opening degree of the charging gate was not adjusted are shown in Table 1.

[0080] [Table 1]

[0081] In this way, by adjusting the opening degree of the charging gate for each region divided in the width direction of the sintering machine, the initial packing density of the charging layer was adjusted, and the deviation in the amount of shrinkage of the sintering raw material charging layer was reduced, thereby improving the sintering yield and the TI strength of the product. [Explanation of symbols]

[0082] 10. Sintering machine 12 Surge Hopper 14 Roll Feeder 15 Charging chute 16 Split Gate 17 Magnetic Brake 18 Level meter 20 Ignition furnace 22 Wind box 24 Blower 26 palettes 28 Position measuring device 29 Thermometer 30 Mine discharge camera 32 Control device 34 Storage area 36 Control Unit 38 Red Tropics 40 Ore supply department 42 Mine Discharge Section

Claims

1. A method for producing sintered ore, comprising the steps of charging raw materials onto a circulating moving pallet to form a charging layer, igniting an upper surface layer of the charging layer using an ignition furnace, drawing air from below the charging layer to combust carbonaceous materials contained in the sintered raw materials to form a sintered cake, and then discharging the sintered cake from a discharge part to produce sintered ore, A method for producing sintered ore, characterized in that the amount of shrinkage of a sintering bed after ignition is measured, and if the amount of shrinkage of the sintering bed is smaller than an appropriate range, the initial packing density of the sintering bed is lowered so that the amount of shrinkage of the sintering bed falls within an appropriate range.

2. A method for producing sintered ore, comprising the steps of charging raw materials onto a circulating moving pallet to form a charging layer, igniting an upper surface layer of the charging layer using an ignition furnace, drawing air from below the charging layer to combust carbonaceous materials contained in the sintered raw materials to form a sintered cake, and then discharging the sintered cake from a discharge part to produce sintered ore, A method for producing sintered ore, characterized in that the shrinkage rate of a sintered ore bed after ignition is measured, and if the shrinkage rate of the sintered ore bed is slower than an appropriate range, the initial packing density of the sintered ore bed is reduced so that the shrinkage rate of the sintered ore bed falls within an appropriate range.

3. 2. The method for producing sintered ore according to claim 1, wherein the measurement is performed at two or more locations in the width direction of the pallet, and the initial packing density of the sintered ore bed is adjusted in the width direction of the pallet.

4. 3. The method for producing sintered ore according to claim 2, wherein the measurement is performed at two or more locations in the width direction of the pallet, and the initial packing density of the sintered ore bed is adjusted in the width direction of the pallet.

5. 2. The method for producing sintered ore according to claim 1, wherein the measurement is performed at two or more locations in the direction of movement of the pallet.

6. 3. The method for producing sintered ore according to claim 2, wherein the measurement is performed at two or more locations in the direction of movement of the pallet.

7. 4. The method for producing sintered ore according to claim 3, wherein the measurement is performed at two or more locations in the direction of movement of the pallet.

8. 5. The method for producing sintered ore according to claim 4, wherein the measurement is performed at two or more locations in the moving direction of the pallet.

9. The method for producing sintered ore according to any one of claims 1 to 8, wherein the measurement comprises measuring a height position of an upper surface of the sintering bed.

10. The method for producing sintered ore according to claim 9, wherein the measurement is performed without contacting the sintering bed.

11. A sintering machine comprising: a circulating pallet; a feeding section for charging sintering raw materials onto the pallet to form a charging layer; an ignition furnace for igniting carbonaceous material on the surface of the charging layer; and an air box installed below the pallet for drawing air from below the charging layer, the sintering machine sintering the sintering raw materials by the combustion heat of the carbonaceous material contained in the sintering raw materials, A sintering machine comprising: a position measuring device for measuring the amount of shrinkage of the sintering bed after ignition; and a function for lowering the initial packing density of the sintering bed so that the amount of shrinkage of the sintering bed falls within an appropriate range when the amount of shrinkage of the sintering bed measured by the position measuring device is smaller than an appropriate range.

12. A sintering machine comprising: a circulating pallet; a feeding section for charging sintering raw materials onto the pallet to form a charging layer; an ignition furnace for igniting carbonaceous material on the surface of the charging layer; and an air box installed below the pallet for drawing air from below the charging layer, the sintering machine sintering the sintering raw materials by the combustion heat of the carbonaceous material contained in the sintering raw materials, A sintering machine comprising: a position measuring device for measuring a shrinkage rate of the sintering bed after ignition; and a function for lowering the initial packing density of the sintering bed so that the shrinkage rate of the sintering bed falls within an appropriate range when the shrinkage rate of the sintering bed measured by the position measuring device is slower than an appropriate range.

13. The sintering machine according to claim 11, characterized in that the position measuring device has a function of measuring two or more positions in the width direction of the pallet and adjusting the initial packing density of the sintering bed in the width direction of the pallet.

14. The sintering machine according to claim 12, characterized in that the position measuring device has a function of measuring two or more positions in the width direction of the pallet and adjusting the initial packing density of the sintering bed in the width direction of the pallet.

15. 12. The sintering machine according to claim 11, wherein the position measuring device measures at least two locations in the direction of movement of the pallet.

16. 13. The sintering machine according to claim 12, wherein the position measuring device measures at least two locations in the direction of movement of the pallet.

17. 14. The sintering machine according to claim 13, characterized in that the position measuring device measures at least two locations in the direction of movement of the pallet.

18. 15. The sintering machine according to claim 14, wherein the position measuring device measures at least two locations in the direction of movement of the pallet.

19. The sintering machine according to any one of claims 11 to 18, wherein the position measuring device measures the height position of the upper surface of the sintering bed.

20. 20. The sintering machine according to claim 19, wherein the position measuring device measures without contacting the sintering bed.

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