Sinter manufacturing method

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, comprising a step of depositing a sintering raw material on a pallet of a sintering machine from a feeder having a sub-gate to form a raw material charging layer; a step of inserting an aeration rod into the raw material charging layer from an upper surface of the raw material charging layer; a step of measuring a height of the upper surface of the raw material charging layer to measure a raw material layer thickness distribution in a horizontal width direction perpendicular to an advancing direction of the raw material charging layer; a step of leveling the upper surface of the raw material charging layer; a step of sintering the sintering raw material by igniting the surface of the leveled raw material charging layer; and a step of blowing oxygen-rich air from above into the raw material charging layer after ignition, in which in the cross section of the raw material fired in the ore discharge section of the sintering machine, at least two of the opening of the sub-gate, the depth of insertion of the ventilation rod, and an oxygen concentration of the oxygen-enriched air in a horizontal width direction are adjusted to make the height of a red heat part from a pallet bottom surface even.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing sintered ore, which is capable of obtaining sintered ore with good properties by controlling the charging state of sintering raw materials used in a sintering machine for producing sintered ore from iron ore. [Background technology]

[0002] Fig. 1 is a diagram for explaining an example of a conventionally known sintering machine to which the sintered ore manufacturing method according to the present invention is applied. In general, sintered ore used as a main raw material in the blast furnace iron-making process is manufactured through the steps shown in Fig. 1. The manufacturing method will be briefly described below according to the flow chart shown in the figure.

[0003] As shown in FIG. 1, sinter raw materials, which are composed of iron ore powder, recovered powder in the steelworks, sintered ore undersize powder, CaO-containing raw materials (CaO-based auxiliary raw materials) such as limestone and dolomite, granulation aids such as quicklime, and coagulants such as coke powder and anthracite, are first stored in hoppers 1. Then, these raw materials are fed from the hopper 1 containing them onto a conveyor at a predetermined ratio, and mixed in a drum mixer 2 for mixing and granulation, with an appropriate amount of water added to adjust the humidity, and granulated to form granulated particles (pseudo particles) with an average diameter of 3.0 to 6.0 mm. Next, the granulated particles are fed from a surge hopper 4 arranged on the sinter machine through a drum feeder 5 and a feed chute 6 to an endless moving sinter machine pallet 7 so as to have a raw material layer thickness (height) of about 400 to 600 mm, forming a raw material charging layer 8. Next, the ignition furnace 9 installed above the raw material charging layer 8 ignites the coagulation material on the upper surface of the raw material charging layer 8. Then, by sucking air from the wind box 10 arranged under the sintering machine pallet 7, the coagulation material (internal coagulation material) in the granulated particles in the raw material charging layer 8 is combusted from the upper layer to the lower layer, and the combustion heat generated at this time heats and melts the granulated sintered raw material, promoting the bonding of the raw materials to become sintered ore. The sintered layer (sintered cake) fired on the sintering machine pallet is transported to the next process through the ore discharge section 11 arranged behind the sintering machine, where it is crushed and sized, and those with a size of 5.0 mm or more are collected as finished sintered ore. 3 is a bed ore hopper, and 17 is a cut-off gate.

[0004] Here, the thickness of the raw material charging layer 8 is closely related to the air permeability of the raw material charging layer (sintering bed) during firing, and the parts with a thinner raw material layer have a smaller air resistance than the parts with a thicker raw material layer. Therefore, more air flows through the parts with a thinner raw material layer than the other parts. In other words, the firing air volume is larger. In such parts with a larger firing air volume, more oxygen is supplied, which promotes the combustion of the coagulant, increases the combustion speed, and the firing progresses faster.

[0005] If there are any parts in the raw material charging layer 8 where the firing air volume is excessively large, the high temperature caused by the combustion of the condensed materials cannot be maintained for a sufficient period of time in those parts, and the progress of the combustion zone will proceed quickly, weakening the structure after firing and reducing the yield of the finished product. Furthermore, if the firing air volume becomes too large, the firing itself will not propagate, and unburned areas will remain in the sintering bed, reducing productivity. The combustion zone is the part of the raw material charging layer 8 where the condensed materials are burning after ignition. The condensed materials in the raw material charging layer 8 burn sequentially from the upper layer to the lower layer, so the combustion zone also moves from the upper layer to the lower layer as firing progresses.

[0006] If the firing speed differs in the horizontal width direction (hereinafter referred to as the "width direction") perpendicular to the moving direction of the raw material charging layer 8 due to the variation in the raw material layer thickness, the operation considers the completion of firing based on the part with the slowest firing speed, so the pallet speed of the sintering machine is slowed down to reduce the production rate, or a part of the ore is discharged from the sintering machine pallet without being fired, increasing the amount of sintered ore undersize and reducing the product yield, and in either case, the production rate has to be reduced. The firing speed is calculated by dividing the raw material layer thickness by the time from when the coagulant on the top surface of the raw material charging layer 8 is ignited to when the combustion zone reaches the bottom of the raw material charging layer 8.

[0007] Therefore, in order to improve the product yield and reduce the amount of sintered ore undersize powder and the aggregate consumption, it is desirable to make the sintering speed constant in the width direction. To achieve this, it is necessary to accurately grasp the distribution of the thickness of the raw material layer 8 in the width direction on the sintering machine pallet and make the distribution of the raw material layer thickness constant in the width direction.

[0008] As a technique for measuring the raw material layer thickness of the raw material charging layer 8 on the sintering machine pallet, a technique has been disclosed in which the raw material layer thickness at the ore feeding section and the raw material layer thickness at the ore discharge section at each position in the width direction are measured using multiple level meters installed in the width direction on the raw material feeding side and the ore discharge side, the shrinkage rate of the sintered ore is calculated from the difference between the measured values, the raw material charging density at the ore feeding section is determined so that the width direction deviations of the cold strength and mechanical properties of the sintered ore are minimized, and the sub-gate opening is adjusted to achieve this raw material charging density (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 5-5589 Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the method for controlling the sintering raw material layer thickness level of a sintering machine described in Patent Document 1, the charging density is controlled by the gate opening degree of the sub-gate. However, since the number of divisions of the sub-gate is limited, there was an unsolved problem that it was difficult to adjust the firing air volume in an area narrower than the width of each sub-gate.

[0011] An object of the present invention is to provide a method for producing sintered ore that can prevent uneven burning of the sintered ore and improve the strength and yield of the sintered ore. [Means for solving the problem]

[0012] In the course of research aimed at solving the problems in the prior art and achieving the above-mentioned object, the inventors discovered that by measuring the thickness of the raw material layer in the ore supply section at each position in the width direction using multiple level gauges installed in the width direction on the raw material supply side, and then adjusting at least two or more conditions among the sub-gate opening, the ventilator insertion depth, and the oxygen concentration in the width direction, it is possible to equalize the firing air volume in each width direction and thus the firing speed. As a result, the height of the red-hot part from the bottom of the pallet becomes uniform in the cross section of the raw materials fired in the sintering machine discharge section, preventing uneven burning and improving the strength and yield of the sintered ore.

[0013] That is, the present invention is a method for producing sintered ore by sintering sintering raw materials loaded on a pallet of a sintering machine, the method comprising the steps of: depositing the sintering raw materials from a feeder having a sub-gate onto the pallet of the sintering machine to form a raw material charging layer; inserting an air vent rod into the raw material charging layer from the upper surface of the raw material charging layer; measuring the height of the upper surface of the raw material charging layer and measuring the raw material layer thickness distribution in the horizontal width direction perpendicular to the traveling direction of the raw material charging layer; leveling the upper surface of the raw material charging layer; igniting the surface of the leveled raw material charging layer to sinter the sintering raw materials; and blowing high oxygen concentration air from above into the raw material charging layer after ignition, wherein at least two of the opening degree of the sub-gate, the insertion depth of the air vent rod, and the oxygen concentration of the high oxygen concentration air in the horizontal width direction are adjusted so that the height of the red-hot part from the bottom of the pallet is uniform in the cross section of the raw materials fired in the ore discharge section of the sintering machine.

[0014] In the method for producing sintered ore according to the present invention configured as described above, (1) When adjusting the sub-gate opening and the insertion depth of the vent rod, after checking the deviation in the firing air volume for each width direction of the sintering machine after adjusting the sub-gate opening, adjust the insertion depth of the vent rod in the width direction of the sintering machine to compensate for the remaining deviation so that the firing air volume becomes constant in the width direction. (2) When adjusting the sub-gate opening and the oxygen concentration in the width direction, after checking the deviation in the firing air volume for each width direction of the sintering machine after adjusting the sub-gate opening, adjust the oxygen concentration in the width direction of the sintering machine using an oxygen blowing device to compensate for the remaining deviation, so that the firing air volume becomes constant in the width direction. (3) When adjusting the insertion depth of the ventilation rod and the oxygen concentration in the width direction, after the raw materials are discharged from the drum feeder, a raw material layer thickness level sensor is used to measure the raw material layer thickness of the raw material charging layer for each width direction of the sintering machine before the cutoff gate, the deviation of the raw material layer thickness from the target value is confirmed, the firing air volume for each width direction of the sintering machine caused by the remaining deviation of the raw material layer thickness in the width direction is calculated, and the insertion depth of the ventilation rod in the width direction of the sintering machine is adjusted to compensate for the deviation of the firing air volume for each width direction of the sintering machine so that the firing air volume is constant in the width direction. If the adjustment of the insertion depth of the ventilation rod is not enough to adjust the amount of adjustment, an oxygen blowing device is used to adjust the oxygen concentration in the width direction of the sintering machine so as to compensate for the remaining deviation and to make the firing air volume constant in the width direction. This is believed to be a more preferable solution. Effect of the Invention

[0015] According to the present invention, by adjusting at least two or more conditions among the sub-gate opening, the ventilating rod insertion depth, and the oxygen concentration in the width direction so that the height of the red-hot part from the bottom of the pallet is uniform in the cross section of the raw material sintered in the ore discharge section of the sintering machine, the sintering speed in the width direction can be accurately controlled to an appropriate state, and high-strength, high-quality sintered ore can be produced with a high yield. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram for explaining an example of a conventional sintering machine to which the sintered ore manufacturing method according to the present invention is applied. [Diagram 2] FIG. 2 is a diagram for explaining one embodiment of a sintering raw material charging section in a sintering machine for carrying out the sintered ore manufacturing method according to the present invention. [Diagram 3] FIG. 2 is a diagram for explaining one embodiment of a thickness detection device for a raw material charging layer in a sintering machine for carrying out the sintered ore manufacturing method according to the present invention. [Figure 4] 4 is a graph for explaining the relationship between air volume and air bar depth in the method for producing sintered ore according to the present invention. [Diagram 5]4 is a graph for explaining the relationship between air volume and oxygen concentration in the method for producing sintered ore according to the present invention. [Figure 6] FIG. 2 is a diagram for explaining one embodiment of a red-hot part in the method for producing sintered ore according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, one embodiment of a method for producing sintered ore according to the present invention will be described with reference to the drawings.

[0018] FIG. 2 is a diagram for explaining one embodiment of the sintering raw material charging section in a sintering machine implementing the sintering ore manufacturing method according to the present invention. In the example shown in FIG. 2, the same members as those in the sintering machine shown in FIG. 1 are given the same reference numerals, and their explanations are omitted. In the example shown in FIG. 2, the sintering raw material 20 is transported on the pallet 7 in a transport direction 13 (the direction of the arrow 13 in the figure). The direction perpendicular to the transport direction 13 is defined as the horizontal width direction 14 of the sintering machine (the direction of the arrow 14 in the figure). The raw material discharged from the surge hopper 4 is dispersed and charged onto the pallet 7 of the sintering machine by the drum feeder 5. In the charging section of the drum feeder 5, sub-gates 15 are arranged at equal intervals in the width direction of the sintering machine, and the amount of the sintering raw material 20 discharged from the corresponding portion can be increased or decreased by adjusting the opening degree of each gate according to a command from a control device (calculating device) not shown.

[0019] At the discharge section of the drum feeder 5, multiple ventilation rods 16 are provided, arranged in the width direction of the sintering machine. By piercing the surface of the charged sintering raw material 20 with the ventilation rods 16, low-density areas can be formed, and the combustion speed of the pierced areas can be increased. There is generally a correlation between the piercing depth of the ventilation rods 16 and the firing air volume, as shown in the example of Figure 4. The depth to which each ventilation rod 16 is inserted into the surface of the sintering raw material 20 can be adjusted.

[0020] A cut-off gate 17 is disposed on the conveying direction 13 side of the drum feeder 5. This cut-off gate 17 is a so-called leveling plate, and is disposed so as to be located at the upper end of the raw material charging layer 8 across the width direction of the sintering machine. The cut-off gate 17 can be adjusted up and down in the height direction from the bottom surface of the sintering pallet 7, and uniforms the raw material layer thickness by consolidating the excess part in the raw material layer thickness direction of the sintering raw material 20 of the sintering machine. The layer thickness of the raw material charging layer 8 after being leveled by the cut-off gate 17 becomes constant, but the cut-off gate 17 is leveled by a method of consolidating the sintering raw material 20. Therefore, if the layer thickness of the raw material charging layer 8 before being leveled by the cut-off gate 17 varies in the width direction, the porosity of the sintering raw material 20 after being leveled will vary in the width direction. Since the firing air volume varies depending on the porosity of the sintering raw material 20, if the layer thickness of the raw material charging layer 8 before being leveled by the cut-off gate 17 varies in the width direction, a deviation in the firing air volume in the width direction will occur.

[0021] An ignition furnace 9 for igniting the sintering raw material 20 is provided on the outlet side of the cut-off gate 17. The surface of the sintering raw material 20 is ignited in the ignition furnace 9, and the raw material is sucked in by a main exhaust fan (not shown) from a wind box 10 arranged below the pallet 7, thereby starting the sintering process.

[0022] The oxygen blowing device 18 is provided on the exit side of the ignition furnace 9. The oxygen blowing device 18 blows high-oxygen-concentration air into the raw material charging layer 8 of the sintering raw materials 20 to increase the combustion speed at the blown-in portion. The oxygen blowing device 18 is divided into chambers along the width direction of the sintering machine, and the flow rate of the high-oxygen-concentration air blown onto the surface of the raw material charging layer 8 can be adjusted for each chamber. There is generally a correlation between oxygen concentration and firing air volume, as shown in FIG. 5.

[0023] In the embodiment shown in FIG. 2, six raw material layer thickness level sensors 19 are arranged at equal intervals on the inlet side of the cut-off gate 17 as the raw material layer thickness detection device. The raw material layer thickness level sensor 19 detects the height of the raw material charging layer 8 of the sintering raw material 20 on the pallet 7 before the start of ignition and suction, and detects the height as the layer thickness level of the raw material charging layer 8 of the sintering raw material 20. The raw material layer thickness detection device is a device that irradiates a laser beam 21 vertically downward from the raw material layer thickness level sensor 19 by the raw material layer thickness level sensor 19 consisting of a laser distance meter arranged at a predetermined interval in the width direction of the pallet 7 of the sintering machine at a predetermined height position on the pallet 7 of the sintering machine, as shown in FIG. 3, and continuously measures the raw material layer thickness of the raw material charging layer 8 charged on the pallet 7 of the sintering machine from the intensity of the reflected laser beam 21.

[0024] In this embodiment, a camera (not shown) is installed in the ore discharge section 11 of the sintering machine shown in FIG. 1, and a cross section of the sintered raw material is photographed when the sintered raw material is discharged from the sintering machine pallet 7. FIG. 6 shows an image of the cross section of the sintered raw material photographed by the camera. In the cross section of the sintered raw material 20, a sintered cake section 22 that has been sintered and has a low temperature, and a red-hot section 23 that has been sintered but still appears red at a temperature of 900°C to 1300°C can be confirmed. As shown in FIG. 6, points p1 to p10 are positioned at equal intervals in the width direction of the sintering machine on the cross section of the sintered raw material, and heights d1 to d10 of the red-hot section 23 to the bottom surface of the sintering machine pallet 7 are measured at each point. If the average value of the measured heights d1 to d10 is D, the points smaller than D have a faster burning speed than the average in the width direction, and the points larger than D have a slower burning speed than the average in the width direction. The object of the present invention can be achieved by reducing the standard deviation σd of the heights d1 to d10, that is, by making the heights d1 to d10 uniform. EXAMPLES

[0025] The present invention was implemented using a Dwight Lloyd type sintering machine with a daily production capacity of 8,000 t and a configuration equivalent to that of the example shown in Fig. 2, with the width of the raw material charging layer 8 being 3.9 m and the raw material layer thickness of the raw material charging layer 8 being 630 mm. Eighteen ventilating rods 16 were installed at equal intervals in the width direction, and the depth of each ventilating rod 16 into the raw material charging layer 8 could be controlled independently. The oxygen blowing device 18 was also configured to be able to control the oxygen concentration in the width direction of the sintering machine by adjusting the oxygen flow rate blown in from the oxygen blowing port extending in the width direction of the sintering machine inside the device.

[0026] In the above-mentioned sintering machine, the target value of the raw material layer thickness of the raw material charging layer 8 was set to 630 mm, and the sintering raw material was discharged from the drum feeder 5. Using the raw material layer thickness level sensor 19, the raw material layer thickness of the raw material charging layer 8 was measured in each width direction of the sintering machine before the cutoff gate 17. As a result, the raw material layer thickness of the raw material charging layer 8 fluctuated from the target value of 630 mm. The deviation of each raw material layer thickness in the width direction from the target layer thickness was obtained, and the sub-gate opening degree was adjusted using the sub-gate 15 divided into 6 sections so that the deviation was reduced. The sub-gate opening degree was adjusted by rotating the rotary handle beside the gate. When the layer thickness of the raw material charging layer 8 in the divided range of the sub-gate 15 was smaller than the target value of 630 mm, the opening degree of the sub-gate 15 was adjusted in the gate opening direction, and when the layer thickness of the raw material charging layer 8 was larger than the target value of 630 mm, the opening degree of the sub-gate 15 was adjusted in the gate closing direction.

[0027] The thickness of the raw material charging layer 8 in each width direction remaining after the sub-gate opening adjustment was measured using the raw material layer thickness level sensor 19. The void ratio of the raw material charging layer 8 after being leveled by the cut-off gate 17, which was caused by the remaining raw material layer thickness deviation in the width direction, was calculated. The void ratio was calculated from the change in the raw material layer thickness of the raw material charging layer 8 before and after being leveled by the cut-off gate 17. At this time, the charging density before being leveled by the cut-off gate 17 was constant in the sintering machine width direction. The firing air volume in each sintering machine width direction was calculated using the Ergin formula from the void ratio of the raw material charging layer 8 in each sintering machine width direction after being leveled by the cut-off gate 17, the suction differential pressure from under the pallet, and the raw material layer thickness calculated as described above. As a result, the firing air volume in each sintering machine width direction after the sub-gate opening adjustment was calculated. At this stage, the adjustment of the sub-gate opening was limited to six divisions, so there were still some areas that could not be adjusted within a range smaller than the number of divisions.

[0028] <When adjusting the sub-gate opening and the insertion depth of the ventilation rod> In this case, after checking the deviation of the firing air volume for each sintering machine width direction after adjusting the sub-gate opening, the insertion depth of the ventilation rod 16 was adjusted in the sintering machine width direction to compensate for the remaining deviation, so that the firing air volume was made constant in the width direction. The ventilation rod 16 was fixed to a base on the walkway deck above the sintering machine, and was configured to be inserted vertically downward from the base toward the raw material charging layer 8. The insertion depth of the ventilation rod 16 was adjusted by loosening the bolts of the base and adjusting the depth to which the ventilation rod 16 was inserted into the raw material charging layer 8. The insertion depth of the ventilation rod 16 was made deeper when the firing air volume was increased, and the insertion depth of the ventilation rod was made shallower when the firing air volume was decreased. The insertion amount of the ventilation rod 16 was determined from the correlation between the insertion depth of the ventilation rod and the firing air volume in the actual machine shown in Figure 4.

[0029] <When adjusting the sub-gate opening and oxygen concentration in the width direction> In this case, after checking the deviation of the firing air volume for each sintering machine width direction after adjusting the sub-gate opening, adjustment was made with the oxygen blowing device 18 to compensate for the remaining deviation. The oxygen concentration in the sintering machine width direction was adjusted using the oxygen blowing device 18 to make the firing air volume constant in the width direction. The oxygen blowing device 18 controlled the oxygen concentration in the sintering machine width direction by adjusting the oxygen flow rate blown in from the oxygen blowing port extending in the sintering machine width direction inside the device. If it is desired to increase the firing air volume, the oxygen blowing amount at that point is increased to relatively increase the oxygen concentration. If it is desired to decrease the firing air volume, oxygen is not blown in at that point to relatively decrease the oxygen concentration. At that time, the relationship between the oxygen concentration and the firing air volume was determined using the correlation in the actual machine in Figure 5.

[0030] <When adjusting the oxygen concentration in the width direction and the insertion depth of the ventilation rod> In this case, after the raw material was discharged from the drum feeder 5, the raw material layer thickness level sensor 19 was used to measure the raw material layer thickness of the raw material charging layer 8 in each width direction of the sintering machine in front of the cutoff gate 17, and the deviation of the raw material layer thickness from the target value of 630 mm was confirmed. The firing air volume for each width direction of the sintering machine caused by the remaining raw material layer thickness deviation in the width direction was calculated in the same manner as described above. In order to compensate for the deviation of the firing air volume for each width direction of the sintering machine, the insertion depth of the ventilation rod 16 was adjusted in the width direction of the sintering machine so that the firing air volume was constant in the width direction. The insertion amount of the ventilation rod 16 was determined from the correlation between the ventilation rod insertion depth and the firing air volume in the actual machine shown in Figure 4. However, the ventilation rod 16 cannot be inserted more than the raw material layer thickness of the raw material charging layer 8 on the sintering machine pallet 7. Therefore, if the raw material layer thickness is t, the adjustment range of the ventilation rod insertion depth is 0 mm to t mm. When the deviation in the firing air volume for each width direction of the sintering machine could not be completely adjusted by adjusting the insertion depth of the vent rod 16 within this range, further adjustment was made with the oxygen blowing device 18. The oxygen concentration in the width direction of the sintering machine was adjusted using the oxygen blowing device 18 to make the firing air volume constant in the width direction. At that time, the relationship between the oxygen concentration and the firing air volume was based on the correlation in the actual machine in Figure 5.

[0031] <When adjusting the sub-gate opening, the insertion depth of the ventilation rod, and the oxygen concentration in the width direction> It is also possible to adjust the sub-gate opening, the insertion depth of the vent rod, and the oxygen concentration in the width direction. In this case, each factor was manipulated so that the firing air volume in the width direction of the sintering machine was ultimately constant.

[0032] In the above procedure, as comparative examples, A: no adjustment, B: only the subgate opening is adjusted, C: only the insertion depth of the vent rod is adjusted, and D: only the oxygen concentration in the width direction is adjusted. As examples of the present invention, E: subgate opening and insertion depth of the vent rod are adjusted, F: subgate opening and oxygen concentration in the width direction are adjusted, G: insertion depth of the vent rod and oxygen concentration in the width direction are adjusted, and H: subgate opening and insertion depth of the vent rod and oxygen concentration in the width direction are adjusted. In each case, a cross section of the sintered raw material in the ore discharge section of the sintering machine was photographed, and the heights d1 to d10 of the red-hot part 23 from the bottom of the pallet 7 and the standard deviation σd of d1 to d10 were obtained. In addition, the shutter strength of the sintered ore and the yield of the sintered ore were measured. The shutter strength of the sintered ore was obtained in accordance with JIS M 8711. The yield of sintered ore was calculated by sieving the discharged sintered ore through a sieve with mesh size of 5 x 15 mm and dividing the weight of the sintered ore by the weight of the base material. The results are shown in Table 1 below.

[0033] [Table 1]

[0034] The results in Table 1 reveal the following:

[0035] First, B: σd when only the subgate opening was adjusted was smaller than A: σd when not adjusted. However, since the adjustment of the subgate opening was limited to six divisions, there were some areas that could not be adjusted completely within a range smaller than the number of divisions.

[0036] In addition, C: σd when only the insertion depth of the ventilation rod was adjusted, and D: σd when only the oxygen concentration in the width direction was adjusted were both smaller than A: when not adjusted. However, since there is an upper limit to the adjustment of both the insertion depth of the ventilation rod and the oxygen concentration in the width direction, there were some areas that could not be fully adjusted.

[0037] Furthermore, E: σd when adjusting the sub-gate opening and the insertion depth of the ventilation rod, F: σd when adjusting the sub-gate opening and the oxygen concentration in the width direction, G: σd when adjusting the insertion depth of the ventilation rod and the oxygen concentration in the width direction were all smaller than B: σd when adjusting only the sub-gate opening, C: σd when adjusting only the insertion depth of the ventilation rod, and D: σd when adjusting only the oxygen concentration in the width direction, and the shutter strength of the sintered ore and the yield of sintered ore were improved.

[0038] Furthermore, σd when adjusting the sub-gate opening and the insertion depth of the ventilation rod and the oxygen concentration in the width direction (H) was similar to σd when adjusting the sub-gate opening and the insertion depth of the ventilation rod (E), σd when adjusting the sub-gate opening and the oxygen concentration in the width direction (F), and σd when adjusting the sub-gate opening and the insertion depth of the ventilation rod (G).

[0039] From the above results, it was found that by adjusting at least two of the conditions of the sub-gate opening, the depth of the ventilation rod, and the oxygen concentration in the width direction, it is possible to equalize the firing air volume in the width direction and the firing speed. As a result, it is possible to make the height of the red-hot part from the bottom of the pallet in the cross section of the raw materials fired in the discharge section of the sintering machine uniform, preventing uneven burning and improving the strength and yield of the sintered ore. [Industrial Applicability]

[0040] The method for producing sintered ore according to the present invention can be suitably applied to sintered raw materials obtained from various blends, particularly when the purpose is to prevent uneven burning of sintered ore and to improve the strength and yield of sintered ore. [Explanation of symbols]

[0041] 1 Hopper 2. Drum Mixer 3. Bedding Ore 4. Surge Hopper 5. Drum Feeder 6 Cut-out Shoot 7 Palette 8 Raw material charging layer 9 Ignition furnace 10. Windbox 11. Mine Discharge Section 13 Conveying direction 14 Width direction 16 Ventilation rod 15 Subgate 17 Cut-off Gate 18 Oxygen blower 19 Laser rangefinder 20 Sintering materials 21 Laser Light 22 Sintering Cake Section 23 Red hot section

Claims

[Claim 1] A method for producing sintered ore by sintering raw materials charged on a pallet of a sintering machine to obtain sintered ore, comprising the steps of: The method includes the steps of: depositing raw materials for sintering from a feeder having a sub-gate onto a pallet of a sintering machine to form a raw material charging layer; inserting an air vent rod into the raw material charging layer from its upper surface; measuring the height of the upper surface of the raw material charging layer to measure the raw material layer thickness distribution in the horizontal width direction perpendicular to the direction of travel of the raw material charging layer; leveling the upper surface of the raw material charging layer; igniting the surface of the leveled raw material charging layer to sinter the raw materials for sintering; and blowing high oxygen concentration air from above into the raw material charging layer after ignition. A method for producing sintered ore, characterized in that a cross section of the raw material fired in the ore discharge section of a sintering machine is photographed with a camera, the deviation in the firing air volume for each width direction of the sintering machine after adjusting the sub-gate opening is confirmed so that the height of the red-hot part from the bottom of the pallet in the cross section of the fired sintered raw material photographed with the camera is uniform, and then the oxygen concentration in the width direction of the sintering machine is adjusted using an oxygen blowing device to compensate for the remaining deviation, thereby making the firing air volume constant in the width direction.

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