JP2006104567A - Method for manufacturing sintered ore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing sintered ore by which a combustion front descending velocity can be increased and sintering productivity can be improved using a simple facility. <P>SOLUTION: A solid carbonaceous material in a red-hot state (red-hot carbonaceous material 26) is added in a proportion of 0.01 to 2.0 mass% to raw materials for sintering to form a sintering raw-material layer of 300 to 900 mm layer thickness. Then ignition is applied to the surface of the raw-material layer while sucking oxygen-containing gas downward from the surface of the raw-material layer to the bottom of the raw-material layer, and the raw materials are sintered while keeping this downward suction. If the addition of the red-hot carbonaceous material into the raw materials for sintering is carried out by feeding the red-hot carbonaceous material into an apparatus for charging the raw materials onto a pallet of a sintering machine or by feeding it to a charging area (sloping surface 10 of a heap of the sintering raw-material layer), reduction in the surface temperature of the red-hot carbonaceous material can be minimized. Moreover, it is preferable to form the sold carbonaceous material into red-hot state by means of microwave heating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a method for producing sintered ore by a Dwytroid (DL) type sintering machine, and more particularly, to a method for producing sintered ore that can increase the rate of lowering the combustion front and improve the sintering production rate.

  In general, in the production of sintered ore by using a Dwytroid type sintering machine, a sintered ore having a particle size of about 10 to 15 mm is laid as a floor layer of about 10 to 80 mm on a great of a sintering pallet. Sintered blended raw materials (hereinafter referred to as solid carbonaceous materials), which are mixed and granulated with iron ore, miscellaneous raw materials, return minerals, auxiliary raw materials and fuel carbonaceous materials (usually solid carbonaceous materials such as powdered coke) , Sintered raw material, or simply raw material) is laid with a layer thickness of 300 mm to 900 mm, and the layer surface is flattened.

  Subsequently, the air is sucked through an air box installed at the lower part of the great, and the surface of the raw material layer is blown from the surface of the sintered raw material packed layer (hereinafter referred to as “sintered raw material layer” or simply “raw material layer”) from the surface to the bottom with an ignition burner. Heating is performed for about 1 minute to ignite the carbon material of the surface layer, and after the ignition, suction is continued for several tens of minutes to produce a sintered cake.

  At this time, the raw material surface layer ignited by the ignition burner has reached approximately 1250 ° C., and the raw material undergoes a melt sintering reaction. At the same time, the air (oxygen-containing gas) passing through the surface layer is heated by being sucked downward from the surface of the raw material layer, the raw material in the lower part is heated and heated, and the carbon material mixed in the raw material is ignited. Thus, a sequential sintering reaction is caused to form a sintered cake.

  That is, in the production of sintered ore, the carbonaceous material in the raw material layer is sequentially burned by air supplied by downward suction to form a combustion zone, and this combustion zone is moved from the surface of the raw material layer toward the bottom. A process is adopted in which the raw material layer is sequentially changed into a sintered cake layer. It seems as if the combustion zone moves from the upper side to the lower side of the sintering material layer. The boundary between this combustion zone and the raw material zone (the raw material layer that has not yet been ignited) is called the “combustion front”.

  On the other hand, looking at the progress of this sintering process for a specific part in the raw material layer, the granulated sintered raw material laid on the grate initially contains about 7 mass% of moisture. The moisture is evaporated by the sensible heat of the gas passing from the upper part to the lower part of the raw material layer, and the raw material is dried. After drying is completed, the raw material temperature starts to rise, and when the temperature reaches about 400 ° C., the blended carbonaceous material is ignited and combusted and heated to about 1300 ° C. When the carbon material burns out, it is cooled by a gas having a low temperature from the upper part to the lower part by suction, and becomes a sintered cake.

  Until the charcoal material is ignited and burned out, it is the combustion part, and the region forming this combustion part is the aforementioned combustion zone, located between the raw material zone and the sintering zone (region existing as a sintered cake) To do.

  Looking at the temporal transition of the combustion zone in the sintered raw material layer, the combustion zone starts from the surface layer where the carbonaceous material is ignited, and moves downward with the passage of time to reach the bottom floor layer. This movement speed of the combustion zone is called “combustion front descending speed” and is an important factor for determining the sintering production rate. And, in order to improve the sintering production rate, it is an important technical problem to increase the combustion front descending speed, and as shown below, to effectively dry the sintering raw material layer Various sintering techniques have been developed.

  In other words, in order to increase the combustion front descending speed that controls the production rate, it is important to quickly bring the temperature of the solid carbonaceous material in the raw material zone to the ignition temperature. Various measures have been taken with the aim of removing or preheating the raw material prior to loading into the pallet.

  In order to raise the temperature of the solid carbonaceous material contained in the sintering raw material of the raw material zone, it is necessary to completely evaporate the water present in the raw material. As long as moisture is present, the raw material temperature remains at 100 ° C. or lower, and the carbonaceous material cannot be ignited. That is, the combustion front descending speed is governed by the drying speed of the raw material. For example, Patent Document 1 discloses a hot air flow between a mineral feeder that supplies raw material to a pallet and an ignition furnace in a Dwytroid type sintering machine. A supply device is installed, hot air is blown from the hot air supply device to the upper surface of the raw material, only the upper layer is heated to a high temperature, and the upper layer of the raw material that has reached a high temperature is ignited in sequence to reduce the thermal shock during ignition. A method for producing sintered ore is disclosed. By heating and drying the raw material upper layer before ignition, an effect of shortening the sintering time is obtained.

  Further, a method developed from the technique described in Patent Document 1 is a method for producing a sintered ore that circulates the exhaust gas of a sintering machine instead of installing a hot air supply device to dry and preheat a raw material layer before ignition. Are known. Furthermore, as a similar technique, a pre-dried sintered raw material is supplied into a pallet by bringing a high-temperature gas into contact with the raw material after granulation by adding moisture to form a raw material layer, and moisture in the sintering process Techniques for reducing evaporation (including crystal water) are also known.

  However, these series of raw material drying (moisture removal) treatment before the ignition operation on the surface of the sintered raw material layer and pre-heat treatment for drying the raw material before charging into the pallet can improve the combustion front descent rate. Although it is excellent in the effect of improving the product yield by promoting the sintering reaction, a large-scale high-temperature gas generator, transportation piping device, gas exhaust treatment device, etc. are required for drying and preheating the entire raw material layer. New problems arise.

As a technique for solving this difficulty, Patent Document 2 discloses 5 to 50 iron ore powder containing 0.3% or more of Fe ₃ O ₄ in a layer within 50 mm from the surface of the raw material layer when the raw material is charged into the sintering pallet. After adding the mass%, between the raw material charging position and the ignition position, first the surface layer part is dried and preheated by blowing downward while blowing hot air on the surface of the raw material layer, and then the surface layer part is heated and heated by microwaves. A method for producing a sintered ore that ignites and sinters in an ignition furnace is disclosed.

  Also, only in the vicinity of the inner wall of the pallet, the region of 5 to 50% by mass from the surface of the raw material layer is dried, heated and heated in advance with high-temperature hot air or microwave, then ignited in an ignition furnace, and then subjected to a sintering reaction A method for producing sintered ore is also known.

These technologies do not achieve drying and temperature rise by passing only the conventional high-temperature gas through the sintering raw material layer before ignition, but use technology that combines oxidation heat generation and microwave heating of Fe ₃ O _4. is there. However, even if these techniques are applied, it is necessary to heat the sintering raw material layer itself by blowing hot air or by microwaves, and thus it is not possible to avoid consumption of a large amount of heating energy.

  In Patent Document 3 and Patent Document 4, the powder that is the auxiliary material is uniformly distributed in the pallet width direction on the upper part of the sintering material layer developed by the present applicant, and in the height direction of the sintering material layer. A technique for controlling the sintering reaction to improve product yield and product quality is disclosed. As auxiliary materials, charcoal materials such as powdered coke, and sintering solvents such as lime powder and serpentine powder are described. In addition, as a charging method and apparatus, a method of adding in a separate line before the raw material supply apparatus to the pallet, a method of spraying on the raw material surface layer immediately before the ignition furnace, immediately after the ignition furnace, etc. are described. ing.

  However, both of these technologies add raw materials containing auxiliary fuel at room temperature to the raw material layer, and control the melt sintering reaction by controlling the carbon concentration and component composition in the pallet height direction. It is a technology that improves product quality and does not attempt to increase the combustion front descent rate.

Japanese Patent Publication No.54-24682 Japanese Patent Laid-Open No. 7-34141 JP 2000-96156 A JP 2000-96157 A

  As described above, in order to improve the sintering production rate, many technological developments have been made to effectively dry and preheat the raw material layer charged in the sintering pallet. However, on the other hand, there is a problem that a large-scale high-temperature gas generator, a gas discharge treatment device, and the like are required, and a great amount of heating energy is required.

  The present invention has been made in view of such a situation, and it is an object of the present invention to provide a method for producing a sintered ore that can increase the combustion front descending speed and improve the sintering production rate with simple equipment. Yes.

  In the process of continuing the study to solve the above-mentioned problems, the present inventors dry and preheat the sintering raw material at that position before reaching the specific position in the sintering raw material layer. I got the idea. If this can be realized, the sintering raw material in the direction of travel of the combustion front is dried and preheated, so it is considered possible to significantly increase the combustion front lowering speed.

  As a method for embodying this idea, a method in which a solid carbon material in a red hot state is dispersed in advance in a sintered raw material in a pallet is conceivable. Therefore, as a result of repeated examination of this method in a normal operation in which suction is performed through a wind box installed at the lower part of the sintering pallet, suction is performed before the combustion front reaches the addition position of the solid carbon material in the red hot state. New knowledge was obtained that it was possible to burn the solid carbon material in the red hot state with the air to be heated, and to dry and preheat the surrounding sintered raw material to increase the rate of descending the combustion front.

  The present invention has been made on the basis of such an idea and knowledge, and the gist thereof is the following method for producing a sintered ore.

  That is, a solid carbon material in a red hot state is added to the sintered raw material at a ratio of 0.01 to 2.0 mass%, and a raw material layer having a layer thickness of 300 to 900 mm is formed using this raw material. This is a method for producing a sintered ore in which the oxygen-containing gas is evacuated downward from the surface to the bottom of the raw material layer while igniting the surface of the raw material layer and continuing the downward suction to sinter the raw material.

  In this method for producing sintered ore, the addition of the solid carbon material in the red-hot state into the raw material for sintering is supplied to an apparatus for charging the raw material into a sintering machine pallet or a portion to be charged. If this is done, it is possible to minimize a decrease in the surface temperature of the red hot carbon material, which is desirable.

  Further, if the solid carbon material in the red-hot state is obtained by microwave heating, the heating device can be reduced in size.

  As used herein, “solid carbonaceous material in a red-hot state” refers to carbon such as powdered coke, powdered coal (anthracite), carbon-containing dust or the like that has been heated to a red-hot state with a surface temperature of 600 ° C. or higher in advance. Is a solid substance containing a major component or a large amount. Hereinafter, it is also referred to as red hot carbon material.

  The ratio of the red hot carbon material is the mass ratio of the red hot carbon material to the sintered raw material that is granulated by the secondary drum mixer and sent to the sintering compound raw material supply device. Hereinafter, it is also referred to as an addition rate.

  According to the method for producing a sintered ore of the present invention, a large-scale high-temperature gas generator, a transportation piping device, a gas discharge treatment device, etc. are not required, and a large amount of heating energy is not consumed. It is possible to increase the combustion front descending speed and improve the sintering production rate.

  Below, the manufacturing method of the sintered ore of this invention is demonstrated in detail with reference to drawings.

  FIG. 1 is a diagram showing a schematic configuration example of an apparatus that can implement the method for producing a sintered ore of the present invention. As the main sintering raw materials, iron ore 1 that is an iron source, return ore 2 that is a recovered sieving product of sintered ore products, limestone 3 that is a solvent, and solid carbon material 4 that is a fuel are respectively supplied to the hopper. It is stored. As the solid carbon material, powdered coke, powdered coal (anthracite), carbon-containing dust, or the like is used. These sintered raw materials are mixed by the primary drum mixer 5, added with water, granulated into pseudo particles in the secondary drum mixer 6, and sent as a sintered raw material to the sintered blended raw material supply device 7.

  The solid carbon material is blended in the drum mixer 6 so that the free carbon concentration is within a range of 2.1 to 5.0 mass% at room temperature. On the other hand, apart from the solid carbon material blended in the drum mixer 6, a solid carbon material (red heat carbon material) 8 in a red hot state having a surface temperature of 600 ° C. or higher is prepared and the calcined granulated into the pseudo particles. Added to the raw material.

  The red hot carbon material may be added anywhere after the outlet of the drum mixer 6, such as the surge hopper inlet 9 of the sintering compound raw material supply device 7, the sintering raw material layer deposition slope 10, and the like. Since the surface temperature of the red hot carbon material is lowered by the contact between the red hot carbon material and the blended raw material, the addition location is preferably as close as possible to the sintered raw material layer, and the sintered raw material layer in the sintering machine pallet 14 is desirable. Immediately before the formation, specifically, (a) a device for charging the raw material into the pallet 14 (charging guide chutes 12 and 13), or (b) a portion for charging the raw material into the pallet 14 (that is, It is particularly desirable to add at the above-mentioned sintered raw material layer deposition slope 10).

  The sinter raw material is cut out from the roll feeder 11 of the sinter compounding raw material supply device 7, and moves horizontally through the charging guide chutes 12 and 13 in the direction indicated by the white arrow in FIG. 1. It is inserted inside. In this charging process, the added red hot carbon material 26 is mixed with the sintered raw material granulated by the secondary drum mixer 6 and dispersed in the sintered raw material layer charged in the pallet. The route indicated by the symbol A in the figure is the case where the red hot carbon material is added at the surge hopper entrance 9 (route A), and B is the case where the red hot carbon material is added at the raw material deposition slope 10 (route B). .

  The added red hot carbon material 26 can raise the temperature of the raw material slightly only by coming into contact with the sintering raw material at room temperature, but the combustion with the air does not proceed because the contact with the air deteriorates. The red hot carbon material 26 charged in the pallet 14 and dispersed in the raw material layer has the wind box group 15 (in this example, 15 wind boxes No. 1 to No. 15 in order toward the traveling direction of the pallet). In FIG. 1 and FIG. 2 to be described later, the combustion starts for the first time by sucking the oxygen-containing gas downward through the numbers corresponding to No. 1, No. 2 and the like enclosed in circles).

  Air is usually used as the oxygen-containing gas.

  The red hot charcoal burns to raise the temperature of the charcoal itself and generate high-temperature combustion gas. As a result, regardless of the ignition or combustion front on the surface of the raw material layer, the moisture of the sintered raw material present around the red hot carbon material evaporates and the raw material temperature rises. That is, due to the combustion heat of the red hot carbon material, the moisture of the raw material around the site where the red hot carbon material exists before the combustion front arrives evaporates, and drying and preheating in the sintered raw material layer are achieved.

At this time, in order for the red hot carbon material to burn, the gas passing through the bed needs to contain oxygen. When the gas sucked from the raw material layer surface is air, the O ₂ concentration in the vicinity of the layer surface is 21 vol%, and even if oxygen is consumed in the combustion zone, the O ₂ concentration of the suction gas in the raw material zone below it is If 6-10 vol% is ensured and the addition rate of the red hot carbon material is 2.0 mass% or less, the red hot carbon material existing in the raw material zone can be burned sufficiently.

  However, when the addition rate of the red hot carbon material exceeds 2.0 mass%, in the raw material zone where the oxygen concentration of the gas is 6 to 10 vol%, oxygen is deficient and the whole amount cannot be burned, and the heat generation effect is not exhibited. Accordingly, the upper limit of the red hot carbon material addition rate is 2.0 mass%. On the other hand, since the improvement effect is small if the addition rate of the red hot carbon material is less than 0.01 mass%, the lower limit of the addition rate is set to 0.01 mass%.

In addition, while the raw material layer passes through the ignition furnace 27, the oxygen concentration of the gas supplied to the red hot carbon material in the lower portion thereof decreases to ₁ to 4 vol% O _2, and the combustion of the red hot carbon material is suppressed. The red hot carbon material does not extinguish, and after passing through the ignition furnace 27, the red hot carbon material burns.

  As described above, the red hot carbon material added and dispersed throughout the raw material layer is the oxygen-containing gas sucked from the surface of the raw material layer in a state before the portion where the red hot carbon material exists moves to below the installation location of the ignition furnace 27. In addition to exhibiting the effect of drying and preheating the raw material zone located below the combustion front by burning, the red hot carbon material is not removed even after the portion where the red hot carbon material exists passes through the place where the ignition furnace 27 is installed. The effect of drying and preheating the raw material zone located below the combustion front by burning continues and allows efficient drying and preheating.

  In other words, in the conventional drying and preheating methods including the techniques disclosed in the above-mentioned Patent Documents 1 and 2, before the ignition, hot air is applied to the surface of the material layer separately from the suction for firing the material. In the operation by the production method of the present invention, the red hot carbon material can be burned by the oxygen contained in the gas after passing through the combustion zone, and by the normal suction and firing. The raw material zone located below the combustion front can be dried and preheated simultaneously.

  As a result, without using a high-temperature gas generator or gas exhaust treatment device for drying and preheating the sintering raw material, and without consuming a great deal of heating energy, the combustion front descent rate is improved and the sintering production rate is improved. Can be improved.

  In the production method of the present invention, the layer thickness of the raw material layer is set to 300 to 900 mm in consideration of the raw material layer thickness at the time of manufacturing the sintered ore by the Dwydroid type sintering machine. If it is in the range of 300 to 900 mm excluding the case where it is thin or thick, it is possible to apply the production method of the present invention in which the red hot carbon material is mixed and dispersed in the raw material layer.

  The particle size of the red hot carbon material is desirably in the range of more than 1 mm and not more than 15 mm. It is ideal that the combustion of the red hot coal is completed before the combustion front reaches the site where the red hot coal is present. If the particle size of the red hot carbon exceeds 15 mm, the combustion is slow, and the combustion front becomes red hot coal. It will reach the location of the material. On the other hand, when the particle size of the red hot carbon material is 1 mm or less, the surface temperature decreases due to contact with the sintered raw material immediately after the addition, and the combustibility of the red hot carbon material becomes extremely poor.

  Next, a method for preparing a red hot carbon material (transportation and heating of a solid carbon material) and a method for addition to a blended raw material will be described.

  FIG. 3 is an explanatory view illustrating a method of heating a solid carbon material and adding it to a sintered raw material granulated by a secondary drum mixer. For example, powdered coke (particle size is preferably 1 to 15 mm) which is a solid carbon material is transported by a truck 16 and driven into a storage tank 17. The coke powder that has been driven in is stored in a storage tank 19 disposed in the vicinity of the sintered blending raw material supply device 7 by an air flow transport system 18. The powder coke cut out from the storage tank 19 is heated by the heating device 20 to be in a red hot state. In this case, it is possible to burn a part of the powder coke by circulating a predetermined amount of air through the heating device 20 and continuously obtain red hot coke (red hot carbon material) by the combustion heat. The exhaust gas from the heating device 20 can be supplied to a sintering machine ignition furnace and used effectively.

  When using a heating device that circulates the air, an auxiliary device for introducing air or supplying exhaust gas to the ignition furnace is required, but the heating device can be made compact by using a microwave as the heating source. Can be Coke has a high microwave reception rate, and efficient heating control is possible even with a small-scale microwave generator.

  As for microwaves, microwaves of 2450 MHz ± 50 MHz, 5.8 GHz ± 75 MHz, 24.125 GHz ± 125 MHz, which are defined in the ISM frequency band designated for industrial use, can be used. 915 MHz ± 25 MHz can also be used if the specified leakage tolerance is not exceeded. Of these, it is most desirable to use microwaves of 2450 MHz ± 50 MHz which are widely used.

  As described above, the solid fuel discharged from the heating device 20 may be added to the sintered raw material, for example, at the surge hopper entrance of the sintered blended raw material supply device 7 (route A), or in the sintering machine pallet width direction. It may be cut out and added to the sintered raw material layer deposition slope 10 (see FIG. 1) by a screw feeder (not shown) installed in (Route B).

  Thus, in the manufacturing method of the present invention, the entire sintered raw material layer or the surface layer portion is not dried and preheated, but the oxygen-containing gas is sucked to correspond to 0.01 to 2.0 mass% of the sintered raw material. By making only a small amount of solid carbonaceous material a red-hot state, the entire sintered raw material layer can be dried and preheated during firing.

  In order to add the red hot carbon material while being widely dispersed in the width direction of the sintering machine pallet by the route B, it is desirable to use an appropriate cutting device.

  FIG. 4 is a diagram illustrating a schematic configuration example of the clipping device. This device is a device having the same function as the powder cutting device proposed by the present applicant in the above-mentioned Patent Documents 3 and 4, and as shown in the figure, a bottomed cylinder 21 (reference numeral M in the figure). And a solid carbonaceous material transport mechanism 22 for extruding the red hot carbon material supplied to the cylindrical body 21 in the longitudinal direction of the cylindrical body 21, and the extruded solid carbonaceous material of the cylindrical body 21. A plurality of solid carbon material cutout holes 24 cut out to the outside are provided at predetermined intervals in the longitudinal direction of the cylindrical body 21. The cutout hole 24 is provided with an opening adjustment gate 23 for adjusting the amount of solid carbon material cutout. In addition, vertical cylinders 21 a for temporarily storing red hot carbon material supplied to the cylinders 21 are provided at both ends of the cylinders 21.

  In this example, the solid carbonaceous material transport mechanism 22 is a screw feeder having helical fins 22b mounted around the rotation shaft 22a. However, other means can be used as long as the solid carbonaceous material can be continuously conveyed in the longitudinal direction of the cylindrical body 21. It may be.

  The cutout hole 24 is desirably provided so as to be higher as it is closer to the vertical cylinder 21a. By doing so, when the opening degree of the cutout hole 24 is made substantially constant, the cutout amount of the solid carbon material cut out from the cutout hole 24 can be made substantially uniform in the longitudinal direction of the cylindrical body 21. In this example, charcoal for discharging the carbon material excessively supplied from the vertical cylinder 21a to the cylinder 21 at the lower part of the longitudinal center part of the cylinder 21 (that is, the bottom M of the cylinder 21). A cutout hole 25 for preventing material clogging is provided.

  By using such a device for adding red hot carbon material, the red hot carbon material is added in a state of being widely dispersed and mixed in the sintered raw material cut out from the sintered blended raw material supply device to form a sintered raw material layer can do. By adding a heating mechanism to the vertical cylinder 21a and / or the cylinder 21, the entire apparatus for adding the red hot carbon material including the heating apparatus 20 can be made compact.

  A production test for sintered ore was performed using a DL-type sintering test apparatus having the configuration shown in FIG. Note that FIG. 2 shows the number of ignition furnaces No. 2 on the exhaust side for two wind boxes. 3 is an apparatus having the same configuration as the apparatus shown in FIG. 1 except that a hood 28 that can be moved to the top of the three wind box and can supply high-temperature gas is provided.

  The sintered raw material used (sintered raw material granulated by the secondary drum mixer 6 and referred to as “mixed raw material” in this example) is the same in each test, and the raw material moisture is 7.0 mass%, 8.5 mass. % Or 10.0 mass%, and the blending amount of the solid carbon material as the fuel was changed to 3.0%, 4.0% or 5.0%.

  In the test, the exhaust gas temperature of each wind box was measured. The pallet speed was adjusted to achieve the maximum exhaust gas temperature in a 14-air box. Further, the ignition start time was subtracted from the time when the exhaust gas temperature of the wind box reached 100 ° C. to obtain the combustion front arrival time (FFP). The combustion front arrival time is measured, the sintered cake is crushed to obtain the product yield, the product production of the sintered ore (the amount of product produced per unit time) is obtained, and the combustion front descent rate [raw material layer Thickness 470 mm / combustion front arrival time (FFP)] and sintering production rate [product production / (effective strand area × sintering time)] were calculated. The sintering time is the time from the start of ignition until the sintered cake comes off the suction strand.

  Table 2 shows the mixing ratios of iron ore, auxiliary materials, solid carbon materials, etc. in the blended raw materials, and Table 3 summarizes the operation conditions carried out in the test. Coke was used for the red hot charcoal. Table 4 shows the test results.

  Case 1 (test operation numbers 1 to 5) is a simple conventional method. The raw material stored in the surge hopper is cut out with a roll feeder, charged into a pallet, ignited with an ignition furnace, air is passed through a wind box. This is the case of suction and sintering. In case 1, the end of the suction wind box is at the end of the ignition furnace and is not sucked before ignition. In test operation numbers 1 to 3, the carbon material ratio in the blended raw material was changed, and in test operation numbers 2, 4, and 5, the raw material moisture was changed.

Case 2 (test operation numbers 6 to 8) is a so-called preheating gas sintering method. As shown in FIG. 3 Move to the top of the wind box, 1 and no. 2 is provided with a hood 28 capable of supplying high-temperature gas, supplying combustion exhaust gas at 400 ° C. (oxygen concentration 19 vol%). 1 and no. The air box of ₂ was made into the negative pressure of 9.8 * 10 < ³ > Pa (1000mmH2O), and the normal temperature air was attracted | sucked from the raw material layer surface. In test operation numbers 6 to 8, the blending ratio and raw material moisture of the blended raw material were changed.

  In case 3 (test operation number 9), instead of supplying combustion exhaust gas at 400 ° C. in case 2, no. 1 and no. A microwave heating device was installed on the surface of the raw material layer at the upper part of the wind box position 2, and the layer surface was preheated and fired. In this case, as in the case 2, No. 1 and no. Suction through 2 air boxes.

  Cases 4-1 to 4-3 (test operation numbers 10 to 23, except for test operation number 19) and case 5 (test operation numbers 24 and 25) are examples of the present invention. Cases 4-1 to 4-3 The installation location of the ignition furnace was the same as in Case 1. In case 5, the ignition furnace is installed at the same location as in case 2, except that the combustion exhaust gas at 400 ° C. is not supplied and no. 1 and no. Room temperature air was sucked through the two air boxes. Red hot coke is added to the raw material layer and burns when air is supplied.

  Cases 4-1 and 5 are cases in which the blended raw material and red hot coke are separately charged into the surge hopper inlet (injection by route A shown in FIG. 1), and cases 4-2 and 4-3 are charged in the pallet. This is the case where red hot coke is supplied onto the raw material deposition slope at that time (input by route B shown in FIG. 1). Case 4-2 is a case where coke is brought into a red hot state by gas heating, and case 4-3 is a case where the coke is brought into a red hot state by microwave heating.

In Table 4, the sintered production rate [t / (h · m ² )] is a product production amount per unit sintering time per effective strand area not including the area of the air box sucked for preheating. Productivity including preheated strands can be evaluated by product production (t / h).

  The wind box location where the exhaust gas temperature is highest and the exhaust gas rising wind box location have a substantially constant relationship, and the higher the combustion front descending speed, that is, the earlier the combustion front arrival time, the higher the sintering production rate. In the case of this test in which the wind box area (the total area of all wind boxes including the areas of the preheating, ignition furnace, and firing windboxes) is the same, Case 2 where a preheating windbox exists, In case 3 and case 5, the area of the firing air box is narrowed by the area of the preheating air box, and even if the production rate is the same, the product production volume including the preheating strand is evaluated as being lower. Will be.

  In the results shown in Table 4, first, regarding the combustion front drop time (FFP), in the test operation numbers 10 to 25 (excluding the test operation number 19) of the present invention example, when a preheating wind box exists, In any case where it does not exist, the combustion front drop time (FFP) is shorter than that in the case of the test operation numbers 1 to 9. That is, the combustion front descending speed obtained from the combustion front descending time (FFP) is improved, and it can be seen that the production method of the present invention is an excellent method capable of improving the sintering productivity (sintering production rate). .

  In addition, in the test operation numbers 12 to 19 and the test operation numbers 23 to 25, the addition rate of the red hot coke was changed. However, in the range of the red hot coke addition rate of 0.01 to 2.0 mass%, When the improvement effect was recognized and the addition rate became 2.5 mass% (test operation number 19), the firing could not be stably performed, and the production rate decreased.

  In test operation numbers 10 and 11 and test operation numbers 20 to 22, the addition rate of red hot coke was made constant and the particle size was changed, but the particle size exceeded 1 mm and 15 mm or less was good, and the particle size was 1 mm or less (test operation) In No. 10), the improvement effect was slightly reduced. The improvement effect was also reduced when the particle size exceeded 15 mm.

  As a heating method, microwave heating (case 4-3, test operation number 20 to 23, except for test operation number 22 having a particle size of more than 15 mm) is more preferable than gas heating (case 4-2, test operation number 15). In addition, the effect of improving the sintering production rate is great, and the addition place was added on the slope of the raw material layer deposition (case 4-3, test operation number) rather than being added by a surge hopper (case 4-1; test operation number 11). 20 to 23, except for test operation number 22 having a particle diameter of more than 15 mm) had a greater improvement effect.

  According to the method for producing a sintered ore of the present invention, it is possible to increase the combustion front descending speed and improve the sintering production rate with simple equipment. It does not require large-scale high-temperature gas generators, transportation piping equipment, gas exhaust treatment equipment, etc., and does not consume a large amount of heating energy, so it can be used easily and effectively for the production of sintered ore. it can.

It is a figure which shows the schematic structural example of the apparatus which can implement the manufacturing method of the sintered ore of this invention. It is a figure which shows the other schematic structural example of the apparatus which can implement the manufacturing method of the sintered ore of this invention. It is explanatory drawing which illustrates the addition method to the sintering raw material (blending raw material) granulated with the heating of the solid carbonaceous material, and the secondary drum mixer. It is a figure which shows the example of schematic structure of a cutting-out apparatus.

Explanation of symbols

1: Iron Ore 2: Return Ore 3: Limestone 4: Solid Carbon Material 5: Primary Drum Mixer 6: Secondary Drum Mixer 7: Sintered Compound Raw Material Supply Device 8: Red Hot Solid Carbon Material (Red Hot Carbon Material)
9: Surge hopper entrance 10: Sintering raw material layer deposition slope 11: Roll feeder 12, 13: Charging guide chute 14: Sinter pallet 15: Wind box group 16: Truck 17: Reservoir 18: Airflow transport system 19 : Storage tank 20: heating device 21: cylinder 21a: vertical cylinder 22: solid carbonaceous material transport mechanism 22a: rotating shaft 22b: spiral fin 23: opening adjustment gate 24: cutout hole 25: carbonaceous material, ie, prevention Cutout hole 26: Red hot carbon material 27: Ignition furnace 28: Hood

Claims (3)

  A solid carbon material in a red-hot state is added to the sintered raw material at a ratio of 0.01 to 2.0 mass%, and a raw material layer having a layer thickness of 300 to 900 mm is formed using this raw material. A method for producing a sintered ore, comprising igniting a surface of a raw material layer while sucking an oxygen-containing gas downward to the bottom of the raw material layer, and continuing the downward suction to sinter the raw material.   The addition of the red-hot solid carbon material into the sintering raw material is performed by supplying the raw material to a device or a portion to be charged in the sintering machine pallet. The manufacturing method of the sintered ore as described in 1 .. The method for producing a sintered ore according to claim 1 or 2, wherein the red-hot solid carbon material is obtained by microwave heating.

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