JP2009097027A - Method for producing sintered ore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a sintered ore, which can enhance productivity by effectively using a returned ore in a dry state. <P>SOLUTION: (1) In a method of producing sintered ore by using a mixture of grains granulated from a raw material to be sintered and all or some of the return ore which is an additive, as a raw material to be sintered and blended, the method for producing the sintered ore includes setting a ratio of the return ore to be added after the granulation of the raw material to be sintered, at 5 to 25 mass% with respect to the raw material to be sintered and blended. (2) The method decreases a water content in the raw material to be sintered and blended which has been added with the return ore by a range of 0.3 to 1.5 mass% compared to a water content of the granulated raw material to be sintered to which the return ore is not added, by adding the return ore. In the methods (1) or (2) for producing the sintered ore, it is preferable to selectively use a coarse grain portion in the return ore which has been classified into the coarse grain portion and a fine grain portion, as the return ore to be added after the granulation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a method for producing a sintered ore using a dweroid-type sintering machine (hereinafter also referred to as a DL type sintering machine), and by adding a return ore after granulating a raw material for sintering. The present invention relates to a method for producing sintered ore.

The raw material for sintering is composed of a plurality of types of iron ore, limestone as a CaO source, auxiliary raw materials as a source of SiO ₂ and MgO, powder coke as a fuel, and return ore. Usually, these raw materials are stored in a raw material tank for each brand, and quantitatively cut out according to the blending. The cut out raw materials and fuel are merged on a belt conveyor for transporting the raw materials and transported to a granulator. In the granulator, the moisture is added to the sintering raw material to perform granulation.

  Furthermore, the raw material for sintering after granulation is charged into a sintering machine as a sintering blended raw material from a hopper called a surge hopper of a raw material charging device, and forms a sintered raw material packed layer on a pallet. The sintered raw material packed bed is transferred along with the pallet in the horizontal direction and ignited at the top of the packed bed. After that, air in the atmosphere is sucked downward through the same layer from the upper side to the lower side of the sintered raw material packed layer, so that the powder coke burns and the raw material particles are heated and heated by the high-temperature gas generated by the combustion. Be warmed. As a result, the sintering reaction proceeds sequentially from the upper layer portion to the lower layer portion of the raw material filled layer. The lump that has been sintered from the upper layer part to the lower layer part of the sintered raw material packed layer is sintered ore (hereinafter, also referred to as “sintered cake”), and after being roughly crushed in the exhausting part of the sintering machine And cooled by a cooler.

  The cooled sintered ore is sieved at about 5 mm, and the sieve top is used as a raw material for blast furnace as a product sintered ore. On the other hand, the undersintered ore is used again as a raw material for sintering as a return ore.

  As described above, in the granulator, moisture is added to the raw material for sintering and granulation is performed. By performing the granulation operation by adding moisture to the raw material for sintering, water becomes a binder and the raw material particles adhere to each other. As a result, the apparent raw material particle size (that is, the raw material particle size after granulation) is increased, and when the raw material for sintering is supplied to the sintering machine, the porosity and the void diameter of the raw material packed layer are increased. , Breathability is improved.

  Thus, the operation of adding moisture to the raw material for sintering is indispensable for facilitating granulation in the mixer and improving the air permeability of the raw material packed layer. However, when the sintering reaction starts, moisture causes air permeability inhibition. As the sintering reaction progresses from the upper layer portion to the lower layer portion, moisture evaporates in the raw material packed layer, and water vapor aggregates to the lower layer portion, thereby reducing the air permeability of the raw material packed layer. Furthermore, since the heat of vaporization is required for the water to evaporate, a high-temperature gas is required as a heat source for supplementing the heat of vaporization, and the evaporated water becomes water vapor to increase the amount of exhaust gas. That is, the addition of moisture causes a decrease in air permeability and an increase in required gas volume (necessary air volume).

  As described above, moisture has both the advantage of increasing (improving) the air permeability and the drawback of decreasing (deteriorating) the air permeability and increasing the required gas amount. For this reason, a technique for effectively utilizing high-temperature gas sensible heat such as exhaust gas has been disclosed in order to maximize the function of moisture and to reduce the adverse effects as much as possible.

  For example, Patent Document 1 discloses a preheating sintering method in which a high-temperature gas is sucked into a raw material packed bed between a mineral feeder for supplying a sintered blended raw material to a pallet and an ignition furnace. According to this preheating sintering method, the raw material temperature is increased, so that the sintering rate can be increased even if the air volume is the same, and the air volume basic unit (necessary for producing a unit mass of sintered ore). Gas amount) can be reduced. In addition, by maintaining the air volume per unit time, the production rate that is an index of the sintering speed, that is, the sinter production per unit time increases per unit sintering machine area. Furthermore, the total energy intensity can be reduced by using exhaust gas sensible heat as a heat source for preheating.

  However, in the method disclosed in Patent Document 1, since a high-temperature gas is sucked into the raw material packed bed between the feeder and the ignition furnace for supplying the sintering compound raw material onto the pallet, the preheating region in the strand Is required. For this reason, there exists a problem that the area of the strand downstream from an ignition furnace reduces and a production amount falls.

  Patent Document 2 discloses a method in which a sintered blending raw material is divided into a surge hopper and a feed section and dried. However, the method disclosed in Patent Document 2 also has a problem in that the production amount decreases because it is necessary to provide a preheating region in the strand as in the method disclosed in Patent Document 1.

  Patent Document 3 discloses a technique in which a low-temperature return ore is heated by a high-temperature gas discharged from a sintering machine and mixed with a new raw material for sintering (hereinafter also referred to as “new raw material”) at normal temperature. Yes. The purpose of this technology is to increase the temperature of the raw material by sensible heat of the returned ore after heating, and to obtain the effect of preheating. However, when high temperature return ore is mixed with other raw materials for sintering and water is added to granulate, there is a problem that part of water evaporates and granulation is inhibited. In Patent Document 4, it is pointed out that this granulation is inhibited, and it is pointed out that high-temperature return ore should be cooled by water addition or the like before mixed granulation.

  On the other hand, a technique for reducing moisture by using a return ore that has been dried using exhaust gas without using high-temperature gas is disclosed. For example, in Patent Documents 5 and 6, two granulators are arranged in series, and a raw material for sintering that does not include return is added to a primary mixer (granulator) while adding a predetermined amount of moisture. A method is disclosed in which the mixture is mixed, and then the return ore is added at the entry side of the secondary mixer (granulator) and granulated by the secondary mixer. In the same document, it is said that the water content is reduced and the production rate is improved by the above method. However, the use of the dried return ore has a problem that moisture is deprived from the humidity-mixed sintering raw material, which causes granulation to be inhibited.

Japanese Patent Publication No. 54-024682 JP 60-089526 A Japanese Patent Laid-Open No. 53-076903 JP 05-009602 A JP 60-052533 A JP 2000-256756 A

  As described above, the conventional technology that prevents the decrease in air permeability caused by moisture and further suppresses the increase in the required gas amount has the problem that the production amount decreases due to the decrease in the strand area of the sintering machine, and the dry state There is a problem in that granulation is hindered by depriving moisture from the sintering raw material in which the return ore is mixed with moisture.

  The present invention has been made in view of the above problems, and the moisture reduction treatment in the raw material for sintering after granulation is not performed on the strand of the sintering machine, but in the feed section (raw material charging device). The object of the present invention is to provide a method for producing sintered ore that can increase the production rate by effectively utilizing dry ore return.

  The present inventors have studied a method for producing a sintered ore that improves productivity and does not inhibit granulation, and obtained the following findings (a) to (c).

  (A) When moisture is added during granulation, the particles approach each other by capillary force using water as a medium. Then, the water moves to the surface layer portion of a combined body of particles (hereinafter also referred to as “post-granulation raw material”). The movement of the particles and water is a granulation phenomenon. When the amount of water is insufficient, the function of capillary force is lowered and the granulation action is inhibited. On the other hand, when the water content exceeds a certain level, the granulating action is saturated. Therefore, there is an appropriate range for the amount of water added during granulation.

  (B) If only the water moved to the surface layer part of the raw material after granulation is removed, the raw material after granulation does not collapse. As a method for removing moisture, it is effective to add a raw material having a low moisture and a relatively dry state, and it is effective to add return ore generated in a sintering plant. However, the amount of return ore generated is not necessarily the same as the amount of return ore required for removing the water transferred to the surface layer portion of the sintering raw material.

  (C) By selectively limiting the return ore to be added to coarse particles, the production rate of the sintered ore can be increased as compared with the case where the return ore to be added is limited to fine particles.

  This invention is completed based on said knowledge, and makes the summary the manufacturing method of the sintered ore shown by following (1)-(3).

  (1) After granulating a raw material for sintering, in a method for producing a sintered ore using a mixture obtained by adding all or part of the return mineral as a raw material for sintered blending, added to the sintered blended raw material after granulation A method for producing a sintered ore, characterized in that the ratio of the ore to be returned is 5 to 25% by mass (hereinafter also referred to as “first invention”).

  (2) In the method for producing sintered ore using a mixture obtained by adding all or part of the return mineral as a sintering compounding material after granulating the sintering raw material, Compared with the moisture content of the raw material for sintering before the addition of the return mineral, the moisture content of the sintered blending material after the addition of the return mineral is reduced in the range of 0.3 to 1.5% by mass. A method for producing the ore (hereinafter also referred to as “second invention”).

  (3) The above-mentioned (1) or (2), wherein a coarse portion of the return mineral classified into a coarse portion and a fine portion is selectively used as the return ore added after the granulation. ) Of the sintered ore described below (hereinafter also referred to as “third invention”).

In the present invention, the “sintering raw material” refers to iron ore, a CaO source, a SiO ₂ source, and MgO.
A secondary material such as a source and a fuel such as powdered coke, a return or the like, or a mixture thereof, which is subjected to various treatments before being charged into a sintering machine. "Means a raw material charged in a sintering machine and forming a sintered raw material packed layer on a pallet.

  According to the method for producing sintered ore of the present invention, in the method for producing sintered ore, after granulating the raw material for sintering, the return ore is added at a ratio of 5 to 25% by mass with respect to the raw material for sintering. By firing this mixture, the productivity of sintered ore is greatly improved. Further, after the granulation of the raw material for sintering, the return mineral is compared with the moisture content of the raw material for sintering before the addition of the return mineral after granulation. The productivity of sintered ore is also improved by adding this so as to decrease in the range of 1.5% by mass and firing this mixture.

  As described above, the present invention is a method for producing a sintered ore that achieves an improvement in productivity by reducing the moisture content of the sintered blended raw material by adding return mineral to the granulated sintering raw material, The first invention is characterized by adjusting the amount of return ore being added, and the second invention is characterized by adjusting the amount of water decrease. And the 3rd invention is the embodiment about the particle size of the addition ore in the case where the amount of the return ore generated is larger than the amount of the return ore to be added in the first and second inventions. Below, the reason and preferable range which prescribed | regulated this invention as mentioned above are demonstrated.

(1) Aspects and preferred ranges of the invention In order to ensure a sufficient granulation effect, an appropriate amount of water is required for the action of capillary force necessary for granulation. For this reason, it is desirable to adjust the moisture content to a relatively high value so that the ungranulated powder is sufficiently reduced. The amount of water required varies depending on the blending conditions of the raw materials for sintering. For example, a large amount of moisture is required for a raw material for sintering having high water absorption, such as maramamba ore and pisolite ore. On the other hand, in the case of a raw material for sintering having a low water absorption like Brazilian hematite, the required amount of water may be relatively small. As described above, it is desirable that the water content is appropriately adjusted according to the blending conditions of the raw materials for sintering.

  In addition, the raw material used for the return ore is recovered from the sieving ore that has been sieved in the stage before charging into the cooler, the sieving ore that has been sieved in the stage after cooling in the cooler, and the dust collector. Dust, sieving ores that have been subjected to sieving before charging into the blast furnace. In this way, all or part of the return ore generated in the sintering factory and the vicinity thereof can be added to the raw material for sintering after granulation.

  The returned ore is generally blended with a sintering raw material before granulation, supplied to a granulator, and granulated together with other sintering raw materials. However, return ore is a fine-grained portion of sintered ore and has low adhesiveness, so even if granulation is performed, it is difficult to contribute to the materialization after granulation. In particular, the ratio of sieving ore is as low as 10% by mass or less with a particle size of 0.25 mm or less, and the ratio of particle size of 2 to 0.25 mm that is considered difficult to contribute to granulation is high. Therefore, it is most effective to add sieving ore to the raw material for sintering after granulation.

  Below, the ratio of the return mineral added after granulation to the sintered blending raw material, the moisture content of the sintered blended raw material before and after the addition of the return mineral, and the ranges of the particle size of the returned ore to be added, and the granulator The preferred types of are described.

  The amount of decrease in the water content by adding the return mineral to the sintered raw material after granulation is preferably about 0.3 to 1.5% by mass. When the amount of decrease in water content is less than 0.3% by mass, a sufficient effect of increasing the production of sintered ore cannot be obtained. On the other hand, when the amount of decrease in water content exceeds 1.5% by mass, granulation is performed. This is because the subsequent raw material collapses and the production increase effect cannot be obtained. In order to realize such a decrease in the moisture content, it is necessary to add about 5 to 25% by mass of returned mineral to the sintered blended raw material in terms of the amount of returned mineral in a dry state.

  On the other hand, the amount of return ore generated differs depending on the sintering machine, has a width of about 20 to 30% by mass with respect to the sintered blending raw material, and does not necessarily match the amount of return ore added. When the amount of return ore is excessive, it is necessary to select the return ore to be added. In this case, a larger production increase effect can be obtained by selectively adding the coarse ore returning ore to the sintering blended raw material and blending the fine grain return ore to the sintering raw material before granulation.

  The classification point for return ore is preferably set to 0.25 mm or more which does not contribute to granulation. Further, the type of classifier is not particularly specified, but for example, a vibration sieve, a fixed sieve, a centrifugal sieve or a wind classifier can be used.

  The type of granulator is not particularly defined, but for example, a rolling granulator or a high-speed stirring mixer can be used. Examples of the rolling granulator include a disk pelletizer in addition to a drum mixer. Further, it has been confirmed that when a high-speed stirring mixer and a rolling granulator are used in combination, the raw material particles are treated in a rough manner, and the bond strength of the raw materials after granulation is dramatically improved. When the bond strength is high, the granulated state is maintained when moisture moves from the surface of the raw material after granulation to the return to the ore, so use a high-speed stirring mixer and a rolling granulator together. Is effective.

(2) Process flow of sinter ore production An example of a process flow based on the present invention is shown below. FIG. 1 is a diagram showing a process flow corresponding to the first invention and the second invention. The arrows in the figure indicate the flow of the raw material for sintering, the raw material for sintering, and the return ore. The raw material 6 for sintering joins on the belt conveyor for raw material conveyance, and is conveyed to the granulator 3. In the granulator 3, granulation is performed by adding moisture 7 to the sintering raw material 6. The granulated sintering raw material 5 is transferred to the surge hopper 2 of the raw material charging device via a belt conveyor. The added ore 4 is added to the sintered raw material 5 after granulation when transferring from the belt conveyor to the belt conveyor or when transferring from the belt conveyor to the surge hopper 2 of the raw material charging device. Mixed. During this mixing, the surface moisture present on the surface of the sintering raw material 5 after granulation moves to the return mineral 4.

  The return ore 4 is obtained by crushing the sintered cake discharged from the sintering machine 1 and sieving after the sieving ore 10 generated when sieving. It consists of the generated ore 11 and dust 12 recovered from the exhaust gas of the cooler 9.

  FIG. 2 is a diagram showing a process flow corresponding to the third invention. The raw material 6 for sintering joins on the belt conveyor for raw material conveyance, and is conveyed to the granulator 3. In the granulator 3, granulation is performed by adding moisture 7 to the sintering raw material 6. The granulated sintering raw material 5 is transported to the surge hopper 2 of the raw material charging device via a belt conveyor. The return ore 4 is classified by the sieve 8, and the return ore 14 on the sieve (that is, the coarse return) is transferred from the belt conveyor to the belt conveyor or from the belt conveyor to the surge hopper 2 of the raw material charging device. At the time of transit to, it is mixed with the sintering raw material 5 after granulation. During the mixing, the surface moisture present on the surface of the sintering raw material 5 after granulation moves to the return mineral 14. On the other hand, the undermining 15 (that is, the fine-grained ore) is granulated together with the raw material 6 for sintering.

  As shown in FIG. 1 and FIG. 2, in the first invention, the second invention, and the third invention, the granulated raw material is reduced in moisture before charging the sintered blending raw material into the sintering machine. There is no need to provide a preheating zone in the machine. As a result, the sintering area in the sintering machine is not reduced, and therefore the moisture content of the granulated raw material can be reduced while securing the productivity of the sintered ore.

Example 1
In order to confirm the effects of the first invention and the second invention, a batch-type sintering test using 60 kg of a sintered compounding raw material was performed, and the air permeability and the production rate were evaluated.

1. Test conditions (1) Raw material blending Table 1 shows the chemical component composition and blending ratio of the raw materials for sintering used in this test.

  As shown in the table, the blending ratio was expressed as a ratio to the new raw material where the sum of iron ore, auxiliary raw materials (dolomite, serpentine powder), limestone and quicklime was 100. Moreover, the compounding ratio of the powder coke was indicated by the ratio of the external number to the total sum of the new raw materials. The above-mentioned new raw material plus powdered coke and return ore was used as the total raw material, and the return rate was 10% by mass with respect to the total raw material.

  For the return ore, the sieving ore 10 subjected to sieving after being discharged from the cooler 9 of the actual sintering machine was used. FIG. 3 is a graph showing the particle size distribution of the returned ore used in Example 1. As shown in the figure, the particle size distribution of this ore is as low as 7% by mass with a ratio of 0.25 mm or less.

(2) Granulation method Using a drum mixer as a granulator, granulation was performed for 4 minutes. Test No. E1 of the present invention was obtained by adding the return mineral after granulation and blending the return mineral by hand mixing with a scoop. Test numbers E2 and E3 of the comparative examples were granulated by blending the return mineral together with other sintering raw materials before granulation. Here, regarding the moisture value, the moisture content before the addition of the return mineral was defined as the moisture content at the time of granulation, and the moisture content after the addition of the return mineral was defined as the moisture content at the time of firing. That is, “moisture content at the time of granulation” means the moisture content (mass%) of the raw material for sintering immediately after granulation, and “moisture content at the time of firing” means return to mineral after granulation. Means the moisture content (% by mass) in the firing stage of the sintered blended raw material to which is added. Therefore, in the comparative example in which granulation is performed after the return ore is added, the moisture content during granulation and the moisture content during firing are the same value.

  Table 2 shows the moisture content and the conditions for adding ore return.

  In the same table, the test number E2 of the comparative example is the moisture content of the same amount as 7.3% by mass, which is the moisture content at the time of firing of the test number E1 of the present invention, and the test number E3 of the comparative example is The moisture content was the same as 7.9% by mass, which is the moisture content during granulation of test number E1 of the present invention. Moreover, as the high-temperature return ore, a return ore sample heated to 600 ° C. by a laboratory heating furnace was used.

(3) Firing test method A sintered blending raw material was charged into a cylindrical sintering pot testing apparatus having a diameter of 300 mm and a depth of 500 mm, and a firing test was performed. During the firing test, the suction pressure in the sintering pot was constant at 9.807 × 10 ³ Pa (1000 mmAq). Using a pressure gauge and a flow meter provided in the cylindrical sintering pot test apparatus, cold air permeability was measured before firing, and hot air permeability was measured after firing.

  The air permeability (JPU) was calculated by the following formula (1).

Breathability = (Q / A) · (h / ΔP) ^0.6 · · · (1)
Here, Q (m ³ / min) is the gas flow rate, A (m ² ) is the cross-sectional area of the pan, h (mm) is the bed height of the raw material charged in the test apparatus, and ΔP (mmAq) is the pressure under the pan It is.

In addition, as an index of productivity, a production rate, which is a sinter production amount per day for 1 m ^{2 of a} sintering machine, was calculated and compared. The production amount of sintered ore means the production amount of a product, that is, the production amount of sintered ore having a particle diameter of 5 mm or more.

2. Test Results FIGS. 4A and 4B are diagrams comparing the sinter quality and production rate in the present invention example and the comparative example. FIG. 4A shows a comparison of cold air permeability, and FIG. A comparison of air permeability is shown, and FIG. 10C shows a comparison of production rates.

  The test number E1 of the present invention example greatly improved both the cold air permeability and the hot air permeability as compared with the test number E2 of the comparative example. Furthermore, the production rate increased by about 6% due to the improvement in hot air permeability. As a result, even if the moisture content during firing is the same amount, granulation is promoted by reducing the moisture content by adding a return mineral after granulation in a state where the moisture content is high, and cold It was confirmed that the air permeability was improved. From the above results, it was clarified that the improvement of the cold air permeability is effective for the improvement of the hot air permeability and the production rate.

  Test No. E1 of the present invention example had a slight decrease in cold air permeability as compared with Test No. E3 of the comparative example, but the hot air permeability was greatly improved. Furthermore, the production rate increased by about 6% due to the improvement in hot air permeability. That is, even when granulation was performed at the same moisture content, the production rate was increased by adding the return mineral after granulation to lower the moisture content. Thereby, it was confirmed that the method of the present invention for reducing the water content after granulation is effective in improving the production rate.

(Example 2)
In order to confirm the effect of the third invention, a batch-type sintering test using 60 kg of a sintered blending raw material was performed to evaluate the air permeability and the production rate.

1. Test conditions (1) Raw material blending Table 3 shows the chemical component composition and blending ratio of the raw materials for sintering used in this test.

  As shown in the table, the blending ratio was expressed as a ratio to the new raw material where the sum of iron ore, auxiliary raw material (serpentine powder) and limestone was 100. Moreover, the compounding ratio of the powder coke was indicated by the ratio of the external number to the total of the new raw materials. The above-mentioned new raw material plus powdered coke and return ore was used as the total raw material, and the return rate was 15% by mass with respect to the total raw material. For the return ore, the sieving ore 10 subjected to sieving after being discharged from the cooler 9 of the actual sintering machine was used.

(2) Granulation method As in Example 1, granulation was performed for 4 minutes using a drum mixer as a granulator. Test No. E4 of the present invention is a granulation of a fine-grained ore (that is, an under-sieving return) that has been subjected to a sieving treatment at 1 mm before granulation together with other sintering raw materials. Coarse-grained ore that had been subjected to sieving treatment at 1 mm later (that is, return on the sieve) was added and hand-mixed with a scoop. Test No. E5 of the comparative example is a fine particle obtained by granulating a coarse-grained ore obtained by sieving at 1 mm before granulation together with other sintering raw materials, and sieving by 1 mm after granulation. Grain return was added and hand-mixed with a scoop. Moreover, test number E6 of a comparative example adds the return ore which does not perform a sieving process after granulation, granulate the return ore which does not perform a sieving process before granulation with other raw materials for sintering. , Hand-mixed with a scoop.

  Table 4 shows the water content and the conditions for adding ore return.

(3) Firing test method A sintered blending raw material was charged into a cylindrical sintering pot testing apparatus having a diameter of 300 mm and a depth of 500 mm, and a firing test was performed. During the firing test, the suction pressure in the sintering pot was constant at 9.807 × 10 ³ Pa (1000 mmAq). Using a pressure gauge and a flow meter provided in the pan testing apparatus, cold air permeability was measured before firing, and hot air permeability was measured after firing. In addition, as an index of productivity, a production rate, which is a production amount of sintered ore having a particle diameter of 5 mm or more per day per 1 m ^{2 of the} sintering machine, was calculated and compared.

2. Test Results FIG. 5 is a diagram showing a comparison of sinter production rates in the present invention example and the comparative example.

  The production rate of the test number E4 of the inventive example increased even when compared with both the test number E5 and the test number E6 of the comparative example. As a result, even if the moisture content during granulation and the moisture content during firing are the same amount, and the return ratio to be blended before and after granulation is the same amount, it is rough as the return ore added after granulation. It was confirmed that the production rate was effectively improved by using the grains.

  According to the method for producing a sintered ore of the present invention, after granulating the sintering raw material, the return ore is added at a ratio of 5 to 25% by mass with respect to the total amount of the sintered blending raw material, and this mixture is fired. By doing so, the productivity of sintered ore is greatly improved. Moreover, after granulating the raw material for sintering, compared to the raw material moisture for sintering after granulation before the addition of return mineral after granulation, the sintered blended raw material moisture after the addition of return mineral is 0.3-1. The productivity of sintered ore is also improved by adding so as to decrease within the range of 5% by mass and firing this mixture. Furthermore, productivity is further improved by selectively using coarse-grained ore as a return ore added after granulation. Therefore, the method of the present invention can be widely applied in the field of raw materials for ironmaking as a method for producing sintered ore that can improve productivity with excellent economic efficiency.

It is a figure which shows the process flow corresponding to 1st invention and 2nd invention. It is a figure which shows the process flow corresponding to 3rd invention. It is a figure which shows the particle size distribution of the return ore used in Example 1. FIG. It is a figure which compares and shows the sintered ore quality and production rate in this invention example and a comparative example, the figure (a) is a figure which shows a comparison of cold air permeability, and the figure (b) is hot air ventilation. (C) is a figure which shows the comparison of a production rate. It is a figure which shows the comparison of the production rate of the sintered ore about this invention example and a comparative example.

Explanation of symbols

1: Sintering machine, 2: Surge hopper, 3: Granulator, 4: Returning, 5: Raw material for sintering after granulation (raw material after granulation), 6: Raw material for sintering, 7: Moisture, 8: Sieve, 9: Cooling machine,
10: sieving ore (returning), 11: sieving ore (returning), 12: dust (returning), 13: sieving ore,
14: Coarse grain return (on sieve) 15: Fine grain return (under sieve)

Claims (3)

  After granulating the raw material for sintering, in the method for producing sintered ore using a mixture obtained by adding all or part of the return mineral as a raw material for sintering, the return ore added after granulation to the raw material for sintering The manufacturing method of the sintered ore characterized by making the ratio of 5-25 mass%.   In the method for producing sintered ore using a mixture containing all or part of the return mineral after granulating the raw material for sintering as the sintering compounding material, the addition of the return mineral after granulation Compared to the moisture content of the sintering raw material before, the moisture content of the sintered blending raw material after the return addition is reduced in the range of 0.3 to 1.5 mass%. Production method.   The sintering according to claim 1 or 2, wherein a coarse portion of the return ore classified into a coarse portion and a fine portion is selectively used as the return ore added after the granulation. Manufacturing method of ore.

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