JP2007284744A - Method for manufacturing sintered ore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing sintered ore by which productivity can be improved by effectively utilizing return fines in a dry state and also to provide a method for pelletizing raw materials for sintering therefor. <P>SOLUTION: The method for manufacturing sintered ore is characterized in that return fines are added after pelletizing raw materials for sintering and the resultant mixture is used as the whole quantity or a part of a sintering raw material. In the above method for manufacturing sintered ore, it is desirable that the addition of the return fines is done before charging the sintering raw material after pelletization into a surge hopper of a raw material charging apparatus. Furthermore, when the mixture in which the return fines are added after pelletization is used as a part of the sintering raw material, it is desirable that this mixture comprises 10 to 40 mass% of the whole quantity of the sintering raw material. Further, it is desirable that the return fines are added in a pelletizer to the sintering raw material after pelletization. <P>COPYRIGHT: (C)2008,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 sintered raw material after granulation is supplied to a sintering machine from a hopper called a surge hopper of a raw material charging device, and is charged on a pallet to form a sintered raw material packed layer. 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. A lump (hereinafter also referred to as “sintered cake”) that has been sintered from the upper layer portion to the lower layer portion of the sintering raw material is roughly crushed in the exhausting portion of the sintering machine, and then cooled by a cooler. .

  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 (hereinafter also referred to as “post-granulated raw material particle size”) increases, and when the sintered raw material is supplied to the sintering machine, the porosity and void diameter of the raw material packed layer are reduced. Increases air permeability.

  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 Literature 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 raw material for sintering 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 ore feeder that supplies the sintered raw material onto the pallet and the ignition furnace, a preheating region is formed in the strand. Necessary. 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 of drying the granulated sintered raw material by dividing it into a surge hopper and a feed section. 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, there is a problem that the use of the dried return ore is deprived of moisture from the humidity-mixed sintered 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 sintered 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 sintered raw material after granulation is not performed on the strand of the sintering machine, but the sintered raw material is supplied to the feed section (raw material loading). Sinter ore production method and sintered granulation method capable of increasing the production rate by effectively utilizing dry ore return ore. The purpose is to provide.

The present inventors have studied a method for producing sintered ore that improves productivity and does not inhibit granulation, and has obtained the following knowledge (a) to (d).
(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 not appropriate, the function of the capillary force is lowered and the granulation is inhibited. Therefore, by optimizing the amount of water added at the time of granulation, it is possible to prevent the material after granulation from collapsing even after drying.
(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.
(C) About the addition of a return ore, there exist the method of adding to the whole quantity of a sintering raw material, and the method of adding to a part of sintering raw material, and the production rate of a sintered ore improves in any case.
(D) When the return ore is added at the final part of the mixer (granulator), the raw material moisture is made uniform by the mixing action. The reason for adding at the final part of the mixer is that if the return mineral is added after granulating the sintered raw material, the effect of moving the surface moisture of the sintered raw material after granulation to the dried return mineral is easily obtained. . On the other hand, if the return ore is added in the first half or the center of the mixer, the return ore is mixed before the granulation is completed, so that it is difficult to obtain the sufficient effect of the present invention.

  The present invention has been completed on the basis of the above findings, and includes a method for producing a sintered ore shown in the following (1) to (4) and a method for granulating a sintered raw material shown in (5). It is a summary.

  (1) In a method for producing sintered ore using a dweroid type sintering machine, a mixture obtained by granulating a raw material for sintering and then adding a return ore is used as the total amount of the sintered raw material. A method for producing ore (hereinafter also referred to as “first invention”).

  (2) In a method for producing a sintered ore using a dwelloid type sintering machine, a mixture obtained by granulating a sintering raw material and then adding a return ore is used as a part of the sintering raw material. A method for producing the ore (hereinafter also referred to as “second invention”).

  (3) The ratio of the mixture obtained by granulating the sintering raw material and adding the return ore to the total amount of the sintering raw material is 10 to 40% by mass, as described in (2) above A method for producing a sintered ore (hereinafter, also referred to as “third invention”).

  (4) Sintering according to any one of (1) to (3) above, wherein returning ore is added before the granulated sintered raw material is charged into the surge hopper of the raw material charging device. A method for producing ore (hereinafter also referred to as “fourth invention”).

  (5) A method for granulating a sintered raw material used in the method for producing a sintered ore according to any one of (1) to (4) above, wherein the granulated sintered raw material is returned to the inside of the granulator. A method of granulating a sintered raw material, which is characterized by adding (hereinafter also referred to as “fifth invention”).

In the present invention, the term "sintering raw material", iron ore, and CaO source, SiO ₂ source, a mixture of fuel, such auxiliary materials, and coke, such as MgO source, prior to the granulation process A raw material is meant, and “sintered raw material” means a raw material after the mixture is granulated.

  According to the method for producing a sintered ore of the present invention, in the method for producing a sintered ore using a DL-type sintering machine, the raw material to which the return ore is added after granulating the raw material for sintering is used as the sintered raw material. When used as a whole amount and fired, the productivity of sintered ore is greatly improved. Moreover, productivity of sintered ore is improved also when using the raw material which added the return ore after granulating the raw material for sintering as a part of sintered raw material. In particular, the productivity of sintered ore is further improved by adding the return mineral to the sintered raw material after granulation in the granulator.

  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 raw material by adding return mineral to the granulated sintered raw material. The invention is characterized in that the moisture content is reduced by targeting the total amount of the sintering raw material, and the second invention is intended for a part of the sintering raw material. The third invention is an embodiment relating to the ratio of the sintering raw material to which the return ore is added in the second invention, and the fourth invention is an embodiment relating to the addition timing of the return ore in the first to third inventions. It is. Furthermore, the 5th invention is the embodiment of the 1st invention-the 4th invention which adds a return ore in a granulator. Below, the reason and preferable range which prescribed | regulated this invention as mentioned above are demonstrated.

(1) Aspects and preferred ranges of the invention The method of the first invention in which the return ore is added to the total amount of the sintered raw material may be used when the raw material flow is granulated as one series, or when granulated as two or more series. Applicable. When granulating in one system, it is desirable to add return ore between the granulator and the surge hopper of the raw material charging device. In addition, when granulating in two or more series, it is desirable to add return ore during the period from when the sintered raw materials divided into two or more series merge to the surge hopper. By adopting such a configuration, since no preheating region is required in the strand, it is possible to prevent a decrease in production due to a decrease in the strand area of the sintering machine.

On the other hand, in the method of the second invention in which returning ore is added to a part of the sintering raw material, when granulating in two or more series, the sintering is divided into two or more series from any series of granulators. It is desirable to add the return ore until the confluence of the raw materials. In this way, when returning ore is added to a part of the sintering raw material, it is more effective to target a sintering raw material containing a clay content such as kaolin and having a relatively high Al ₂ O ₃ content. is there. This is because the clay-like substance has a characteristic that the bond between particles is strengthened due to a decrease in moisture after granulation.

In the second invention, it is desirable that the ratio of the mixture obtained by granulating the sintering raw material and then adding the return to the total amount of the sintering raw material is 10 to 40% by mass. If the ratio is less than 10% by mass, the surface moisture of the sintered raw material after granulation is not sufficiently transferred to the dried ore, and the effect of the present invention is difficult to obtain. On the other hand, the ratio is 40% by mass. If it exceeds the upper limit, it becomes difficult to strengthen the interparticle bond when a raw material for sintering containing a relatively high content of Al ₂ O ₃ containing clay such as kaolin is used, and the effect of the present invention is reduced. Because.

  In order to ensure a sufficient granulation effect, an appropriate amount of water is required to exhibit the action of the capillary force necessary for granulation. For this reason, it is desirable to adjust the moisture content to a relatively high value. When all raw materials are granulated in one or two lines, the required amount of water varies depending on the blending conditions of the raw materials for sintering. For example, a large amount of water 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 with low water supply like Brazilian hematite, the required amount of water may be relatively small. As described above, it is desirable to appropriately adjust the water content 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 its surroundings can be added to the sintered raw material 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, sieving ore has a low ratio of particle size of 0.25 mm or less as low as 10% 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 sintered raw material after granulation.

  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 granulation state is maintained when moisture moves from the surface of the raw material after granulation to return to the ore, so use a high-speed stirring mixer and a rolling granulator together. It 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 by one-line granulation of a sintering raw material corresponding to the first 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 sintered raw material 5 after granulation is transferred to the surge hopper 2 of the raw material charging device via a belt conveyor. The added return 4 is mixed with 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. Is done. During this mixing, surface moisture present on the surface of the sintered 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 oresite 11 and dust 12 recovered from the exhaust gas of the cooler 9.

  FIG. 2 is a diagram showing a process flow by two-series granulation of a sintering raw material corresponding to the second invention. The raw material 6 for sintering is divided into two lines and conveyed to the granulators 3a and 3b by a belt conveyor for conveying the raw material. In the granulator 3a, moisture 7 is added to the raw material 6 for sintering and granulation is performed. As described above, when a high-speed agitating mixer and a rolling granulator are used in combination as the granulator 3a, the bond strength is dramatically improved, so that the granulated state is maintained even after the return is added. Thus, the effect of the present invention is enhanced. In the granulator 3b, moisture 7 is added to the sintering raw material 6 to perform granulation.

  Sintered raw materials 5a and 5b after granulation are transferred to the surge hopper 2 of the raw material charging device via a belt conveyor. The return ore 4 is added to the sintered raw material 5a before reaching the junction 8 with the sintered raw material 5b. In this manner, by adding the return mineral 4 before reaching the junction 8, the surface moisture of the granulated sintered raw material 5 a moves to the return mineral 4.

  As shown in FIGS. 1 and 2, in the first and second inventions, the granulated raw material is reduced in moisture before the sintered raw material is charged into the sintering machine. There is no need to provide it. Thereby, the sintering area in a 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.

  FIG. 3 is a diagram showing a process flow by one-line granulation of a sintering raw material corresponding to the fifth 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. At this time, the return mineral 4 is added at the final part 3c of the granulator 3, and the sintered raw material 5 after granulation and the return mineral 4 are mixed using the granulator. By setting it as such a structure, compared with the case where a return ore is added in places other than a granulator, such as on a belt conveyor, productivity of a sintered ore improves notably. Furthermore, it is more desirable that the return ore 4 is introduced from the outlet side of the granulator. This is because it is possible to remove the surface moisture of the sintered raw material following the granulation.

Example 1
In order to confirm the effects of the first invention, the fourth invention, and the fifth invention, that is, the effect of the present invention for all sintered raw materials, a batch-type sintering test using 60 kg of sintered raw materials was carried out, and air permeability And the production rate was evaluated.

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

  As shown in Table 1, the blending ratio was expressed as a ratio with respect 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 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 based on 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. 4 is a graph showing the particle size distribution of the return mineral used in Example 1. As shown in the figure, the particle size distribution of this ore is as low as 7% 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. T1 of the present invention was obtained by adding the ore after granulation and blending the ore by hand mixing with a scoop. Test numbers T2 and T3 of the comparative examples were granulated by blending the return mineral together with other sintered 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 during granulation, and the moisture content after the addition of the return mineral was defined as the moisture content during firing. That is, the “moisture content during granulation” means the moisture content (mass%) of the sintered raw material immediately after granulation, and the “moisture content during firing” is the addition of return mineral after granulation. It means the moisture content (% by mass) in the firing stage of the sintering raw material. Therefore, in the comparative example in which granulation is performed after adding the return mineral, 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 T2 of the comparative example is the moisture content of the same amount as 7.3% by mass which is the moisture content during firing of the test number T1 of the present invention example, and the test number T3 of the comparative example is The moisture content was the same as 7.9 mass%, which is the moisture content during granulation of test number T1 of the invention example. 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 sintering 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. Further, as a productivity index, a production rate, which is a daily production amount per 1 m ^{2 of a} sintering machine, was calculated and compared.

2. Test Results FIGS. 5A and 5B are diagrams showing a comparison of the quality of sintered ore in the present invention example and the comparative example, in which FIG. 5A is a comparison of cold air permeability and FIG. 5B is a hot air permeability. (C) shows a comparison of production rates.

  The test number T1 of the inventive example greatly improved both the cold air permeability and the hot air permeability as compared with the test number T2 of the comparative example. Furthermore, the production rate increased by 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.

  The test number T1 of the present invention example had a slight decrease in cold air permeability as compared with the test number T3 of the comparative example, but the hot air permeability was greatly improved. Furthermore, the production rate increased by 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 effects of the second invention, the third invention, and the fifth invention, that is, the effect of the present invention when adding the return ore after granulation targeting a part of the sintered raw material, the same as in Example 1 A batch-type sintering test was conducted and the results were evaluated.

1. Test conditions (1) Raw material blending Table 3 shows the chemical composition and blending ratio of the sintered raw materials.

  As shown in Table 3, the blending conditions of the new raw material were the same as in Example 1. The target raw material to which the return ore is added (hereinafter also referred to as “drying target raw material”) was a sintered raw material obtained by granulating a mixed raw material of West Angelus ore, quicklime and limestone. 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 ratio of returning ore blending was 10% by mass with respect to all raw materials.

(2) Granulation and firing test method Two series granulation was adopted in all tests, and granulation was performed under the following conditions (a) and (b).

(A) Raw material to be dried (raw material subject to return ore addition)
The mixture was granulated for 1 minute using a high-speed stirring mixer, and granulated for 4 minutes using a pan pelletizer.

(B) Raw materials that are not subject to drying (raw materials that are not unpaired with the addition of return ore)
Granulated for 4 minutes using a drum mixer. The moisture content during firing was 7.4% by mass in all tests.

  In test number T4 of the present invention example, the return mineral was added after granulation, and the return mineral was blended by hand mixing with a scoop. In addition, test numbers T5 and T6 of the present invention example were obtained by adding the ore after granulation, test number T5 was mixed for 15 seconds, and test number T6 was mixed for 60 seconds using a drum mixer. The test number T7 of the comparative example was granulated by blending the return ore with other sintered raw materials before granulation.

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

  In all tests, the moisture content during granulation was the same at 9.5% by mass. Moreover, the high temperature return ore used the return ore sample heated at 600 degreeC with the laboratory heating furnace.

  The firing test was carried out under the same conditions as in Example 1 with the sintered raw material charged into a cylindrical sintering pot test apparatus.

2. Test Results FIG. 6 is a diagram showing a comparison of the production rates of sintered ore for the present invention example and the comparative example. As shown in the figure, in test numbers T4 and T5 of the present invention example that was granulated at a moisture content of 9.5% by mass and then dried, compared to test number T7 of the comparative example that was not dried. The production rate has improved significantly. In particular, in test number T5, which is a test for the fifth invention in which return ore was added in the granulator, the increase in the production rate was extremely remarkable.

  However, in test number T6, which is a test for the fifth invention in which the mixing time in the drum mixer is extended to 60 seconds, the degree of improvement in production rate and air permeability is reduced as compared with the cases of test numbers T4 and T5. From this result, it was confirmed that the mixing time of the return mineral and the raw material after granulation is preferably less than 60 seconds.

  According to the method for producing a sintered ore of the present invention, in the method for producing a sintered ore using a DL-type sintering machine, the raw material to which the return ore is added after granulating the raw material for sintering is used as the sintered raw material. By using as a whole amount and firing, the productivity of sintered ore is greatly improved. Moreover, productivity of sintered ore is improved also when using the raw material which added the return ore after granulating the raw material for sintering as a part of sintered raw material. In particular, in the granulator, the productivity of the sintered ore is further remarkably improved by adding the return mineral to the sintered raw material after the granulation. Therefore, the method of the present invention can be widely applied as a method for producing sintered ore that can improve productivity with excellent economic efficiency.

It is a figure which shows the process flow by 1 series granulation of the sintering raw material corresponding to 1st invention. It is a figure which shows the process flow by 2 series granulation of the sintering raw material corresponding to 2nd invention. It is a figure which shows the process flow by 1 series granulation of the sintering raw material corresponding to 5th 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 sinter quality 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 a comparison of hot air permeability. The figure (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, 3a, 3b: Granulator, 3c: Final part of granulator, 4: Returning, 5, 5a, 5b: Sintered raw material after granulation (granulation Post raw material), 6: Raw material for sintering,
7: Moisture, 8: Confluence, 9: Cooling machine, 10: Sieve ore (returning), 11: Sieve ore (returning), 12: Dust (returning), 13: Sieve ore

Claims (5)

  In the manufacturing method of the sintered ore using a dweroid type sintering machine, the mixture of the sintering raw material is used as the total amount of the sintering raw material, which is obtained by granulating the sintering raw material and then adding the return ore. Method.   In a method for producing a sintered ore using a dweroid type sintering machine, a mixture of granulated sintering raw materials and then adding a return ore is used as a part of the sintered raw materials. Production method.   3. The sintered ore according to claim 2, wherein the ratio of the mixture obtained by granulating the sintering raw material and adding the return ore to the total amount of the sintering raw material is 10 to 40% by mass. Manufacturing method.   The method for producing sintered ore according to any one of claims 1 to 3, wherein returning ore is added before the granulated sintered raw material is charged into a surge hopper of a raw material charging device. It is the granulation method of the sintering raw material used for the manufacturing method of the sintered ore in any one of Claims 1-4, Comprising: Returning ore is added in the granulator to the granulated sintering raw material. A method for granulating a sintered raw material.

Images