JP2007138246A - Preliminary treatment method and preliminary treatment device for sintering raw material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preliminary treatment method for a sintering raw material where the value of moisture in a sintering raw material is properly regulated and controlled, thus, even in the case the content of the moisture in the sintering raw material is varied, preliminary treatment for the sintering raw material can be efficiently performed without deteriorating productivity. <P>SOLUTION: A moisture-containing sintering raw material is treated through a kneading stage, a granulating stage and a drying stage in this order, a part of the sintering raw material after the drying in the drying stage is returned to the moisture-containing sintering raw material or to the kneading stage, and the content of the moisture in the sintering raw material in the kneading stage or granulating stage is regulated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pretreatment method and a pretreatment apparatus for a sintered raw material, and in particular, even when the moisture content of the sintered raw material fluctuates, the pretreatment of the sintered raw material is efficiently performed without deteriorating productivity. The present invention relates to a pretreatment method and a pretreatment apparatus for a sintering material.

  In the production of sintered ore, the sintering raw material is pre-treated before the raw material is supplied to the sintering machine.

  In the pre-treatment, first, sintered raw materials such as iron ore, auxiliary materials (for example, lime powder, serpentine), fuel (for example, coke powder) are mixed with a kneading machine such as a Redige mixer or an Eirich mixer. Kneading step of kneading while adjusting the amount of addition, and subsequent granulation step of granulating while adjusting moisture as necessary with a granulator such as a drum mixer or pelletizer to produce pseudo particles (also referred to as a granulated product) And process through. Pseudo particles are particles in which fine powder particles of 0.5 mm or less are generally attached to 1 to 3 mm core particles. In addition, in order to improve kneadability and granulation property, a sintering step may be provided before the kneading step, and the sintered raw material may be ground by a ball mill or the like.

  At this time, it is necessary that the pseudo particles are difficult to collapse in the sintering machine (wet zone, dry zone, etc.) in the subsequent sintering step. By making the sintering raw material into pseudo particles in this way, air permeability in the sintering raw material packed layer (sintering bed) in the sintering machine can be improved, and the productivity of the sintering machine can be improved.

  That is, the pseudo particles are required to have a strength (crushing strength) that does not collapse in the conveying process to the sintering machine and in the sintering machine. In order to develop such strength, appropriate pretreatment of the sintering raw material is necessary, and at the time of kneading and granulation, the moisture content of the sintering raw material is appropriately adjusted so as to achieve as uniform mixing as possible. It is important to knead and granulate so that fine powder particles adhere well around the core particles to produce pseudo particles that are difficult to disintegrate.

  Further, in recent years, the supply of iron ore such as hematite, which has been used as a mainstream in sintering machines, has been reduced, and iron ore, maramamba ore having a high crystal water content such as pisolite ore (eg, 3% by mass or more), The supply of fine phosphorus ore such as high phosphorus block man and pellet feed is increasing. Such iron ore has a feature that it is difficult to granulate as compared with conventionally used iron ore, and it is necessary to perform more appropriate pretreatment.

  Under these circumstances, a technology is known in which the sintered raw material is granulated to form pseudo-particles and then dried to increase the crushing strength of the pseudo-particles and suppress the pseudo-particle transport process and collapse in the sintering machine. (For example, refer to Patent Document 1).

  On the other hand, sintered raw materials are transported from the raw material yard to a pretreatment facility for sintered raw materials with a dump truck, etc., but the sintered raw materials are often piled up in the outdoor raw material yard, and when it rains When the raw material is wet, the water content (= water mass / sintered raw material mass-wet) increases rapidly from the usual several percent to several ten percent.

  Usually, the above-mentioned kneading and granulating operations vary depending on the kneading method and the granulating method, but the water content is often about 5 to 10%. Further, the yield of the pseudo particles is deteriorated, and the strength of the produced pseudo particles is weak, and the amount of the pseudo particles that are disintegrated in the course of conveyance or in the sintering machine increases. If the moisture content is low, it can be dealt with by newly adding moisture in the kneading process etc., but if the moisture content is high, it is difficult to cope with it, so the productivity of sintered ore during rainy weather is greatly There was a problem of lowering. In addition, if the moisture content of the sintering raw material to be processed in the sintering process is too high, there is a problem that the fuel consumption rate increases due to the need for heat compensation for the latent heat of vaporization and sensible heat rise in the sintering machine. did.

  As a countermeasure, there is a means of providing a drying step before kneading to reduce the moisture content of the sintered raw material containing about 10% of moisture, but introducing a new drying equipment for that purpose is There is a problem that the production cost of the ore is raised. In addition, even if a drying step is provided before the kneading step, it is difficult to uniformly control the degree of drying with moisture remaining, so that normally the sintering raw material reaches an equilibrium moisture content (moisture content). However, in this case, it is necessary to add a large amount of water again in the kneading step or the granulation step to adjust the moisture content to an appropriate range (for example, 5 to 10% by mass). Is inefficient.

In addition, as a method for adjusting the moisture content, a technique is known in which the yield drop-down sintered ore on the side of the sintering machine is returned to the kneading process or granulation process to return to the kneading process and control the moisture content in the sintered raw material. (For example, refer to Patent Document 2). However, since the return mineral has a coarse particle size and high hardness, the degree of wear of the stirring blades of the kneader and granulator is high. For example, when a Redige mixer is used for the kneader, the life of the stirring blade is usually normal. There was a problem that the one for 0.5 to 1 year was shortened to about one month.
JP-A-3-215629 Japanese Patent Laid-Open No. 7-62456

  The present invention has been proposed in view of the circumstances described above, and increases the strength of the pseudo particles that are the granulated product of the sintering raw material to such an extent that the pseudo particles can be prevented from collapsing during conveyance or sintering, Even when the moisture content of the sintering raw material becomes high during rainy weather, etc., kneading and granulation, or pulverization, kneading and granulation can be adjusted to an appropriate moisture range and processed to deteriorate productivity. It is an object of the present invention to provide a pretreatment method and pretreatment apparatus for a sintering raw material that can efficiently preprocess the sintering raw material without any problem.

The sintering raw material pretreatment method according to the present invention has been proposed to solve the above-described problems, and has the following features.
(1) In the sintering raw material pretreatment method, a sintering raw material containing moisture is processed through a kneading step, a granulating step, and a drying step in this order, and a part of the sintered raw material after being dried in the drying step Is returned to the moisture-containing sintered raw material or the kneading step, and the moisture content of the sintered raw material in the kneading step or the granulating step is adjusted.
(2) In the sintering raw material pretreatment method, the sintering raw material containing moisture is processed in the order of pulverization step, kneading step, granulation step, and drying step, and the sintered raw material after drying in the drying step Returning a part of the sintered raw material containing moisture, the pulverizing step, or the kneading step to adjust the moisture content of the sintered raw material in the pulverizing step, the kneading step, or the granulating step; Features.
(3) The sintering raw material powder according to (1) or (2), wherein the drying in the drying step is fluidized bed drying with gas and accompanied by the exhaust gas after flowing. The recovered powder is returned to the sintered raw material containing moisture, the pulverizing step, or the kneading step as a part of the dried sintered raw material.
(4) In the sintering raw material pretreatment method according to any one of (1) to (3), the moisture content of the sintering material containing the moisture, and the moisture content of the sintering material in the kneading step, Alternatively, the sintered raw material after drying is measured so that the moisture content of the sintered raw material in the granulation step is measured and the moisture content measured in the kneading step or the granulation step is within the target moisture content range. Or a return amount of the sintered raw material after drying and a processing amount of the sintered raw material containing the moisture are adjusted.
(5) In the pretreatment method of the sintering raw material according to (4), the moisture content is measured continuously or intermittently, and the moisture content measured in the kneading step or the granulating step is the target. The return amount of the sintered raw material after drying, or the return amount of the sintered raw material after drying and the moisture in accordance with the change in the moisture content of the sintered raw material containing the water so as to be in the moisture content range The processing amount of the sintering raw material containing is sequentially adjusted.
(6) In the sintering raw material pretreatment method according to any one of (1) to (5), the returned sintered raw material after drying is temporarily stored, and the stored sintered raw material after drying is stored. Is used to adjust the moisture content of the sintered raw material in the pulverizing step, the kneading step, or the granulating step, instead of the returning sintered raw material after drying.
(7) In the pre-processing method of the sintering raw material according to (5), when the moisture content of the sintering raw material containing the moisture is changed, being adjusted in the pulverization step, the kneading step, or the granulation step So that the moisture content of the sintered raw material is kept at the moisture content before being affected by the change, the amount of the stored sintered raw material used after drying, or the use of the stored sintered raw material after drying. The amount of the sintered raw material containing the moisture is adjusted, and then the moisture content of the sintered raw material before the pulverization step or before the kneading step is the amount of the sintered raw material containing the moisture after the moisture content change. The stored amount of the sintered raw material after drying is the same as the return amount so that the moisture content is determined by the balance between the processing amount and the return amount of the sintered material after drying to return. In the direction to make the use amount of the stored sintered raw material after drying, 6. The pre-sintering raw material according to claim 5, wherein the storage amount of the sintered raw material after drying and the processing amount of the sintering raw material containing moisture are changed continuously or intermittently. Processing method.
(8) In the sintering raw material pretreatment method according to any one of (1) to (7), a binder is added in the kneading step or the granulating step.
(9) In the sintering raw material pretreatment method according to any one of (1) to (8), 20 to 100 of Malabamba ore, pisolite ore, or maramamba ore and pisolite ore are added to the sintering raw material containing moisture. It is characterized by containing mass% (dry).
(10) In the sintering raw material pretreatment method according to (8) or (9), the binder is a polyacrylic acid-based dispersant or quicklime.
(11) A sintering raw material pre-processing apparatus, which includes a storage tank for moisture-containing sintering raw material, a transport apparatus for transporting the sintering raw material cut out from the storage tank, a subsequent kneader, and granulation And a drier, and a return device for returning a part of the dried product dried by the drier to the transport device or the kneader.
(12) A sintering raw material pre-processing apparatus for transporting a sintered raw material storage tank containing moisture, a returned sintered raw material storage tank, and both the sintered raw materials cut out from both the storage tanks A conveying device, a subsequent kneader, a granulator, and a dryer, and a return device that returns a part of the dried product dried by the dryer to the storage tank of the sintered raw material to be returned, It is characterized by having.
(13) In the sintering raw material pretreatment apparatus according to (11) or (12), the sintering raw material storage tank containing moisture, or the sintering raw material storage tank containing moisture and the return are returned. The storage tank for the sintered raw material is characterized in that the amount of the raw material cut out can be controlled.
(14) The sintering raw material pretreatment apparatus according to (11) or (12) is characterized in that a pulverizer is provided at the rear stage of the conveying apparatus, and the kneader is provided at the subsequent stage.
(15) In the sintering raw material pretreatment apparatus according to any one of (11) to (13), the dryer has a function of collecting and collecting fine powder accompanying the exhaust gas after flowing. And the return device is a return device that returns the collected fine powder.
(16) In the sintering raw material pretreatment apparatus according to any one of (11) to (14), the moisture measuring apparatus for the sintering raw material containing the moisture, the kneader inlet side, and the kneader outlet side The apparatus further comprises a moisture measuring device for sintering raw materials on at least one of the inlet side of the granulator and the outlet side of the granulator.

  In addition, the meaning of the water in the “moisture ratio” according to the present invention is free water and does not include crystal water.

  Further, the moisture content is defined as (moisture mass in sintered raw material / mass of sintered raw material (wet)) × 100.

  The sintering raw material pretreatment method according to the present invention provides a drying step of the granulated pseudo particles to improve the strength of the pseudo particles and circulate a part of the sintered raw material after drying to increase the moisture value. By adjusting, even if the moisture content of the sintering raw material increases and fluctuates under the influence of heavy rain due to the rainy season, typhoon, etc., pre-processing the sintering raw material efficiently without deteriorating productivity Is possible.

  The sintering raw material used by this invention is a sintering raw material containing an iron ore while containing a water | moisture content.

  In addition to iron ore, in addition to iron ore, ironmaking dust (blast furnace dust collection dust, converter dust, etc.), limestone, dolomite, serpentine, quartzite, olivine, coke powder, anthracite, etc. A seed material or a mixed raw material to which two or more kinds are added can be used.

  The iron ore is not limited as long as it is used as a normal sintering raw material. In addition to hematite and magnetite, iron ore containing a large amount of crystal water (for example, goethite, limonite (pisolite ore), etc.) In addition, even porous materials (for example, maramamba ore) can suppress the collapse of the granulated material (pseudoparticles), and even when the moisture content of the sintered raw material rises rapidly in the rain, kneading It is possible to perform pretreatment of the sintered raw material efficiently without deteriorating the productivity by adjusting the processing to an appropriate moisture range, or granulation, or pulverization, kneading or granulation.

  As a ratio of the iron ore contained in the granulated product of the sintered raw material before drying, 20 to 100% by mass (dry) is preferable. In particular, when maramamba ore or pisolite ore is used as the iron ore, the proportion of maramamba ore, the proportion of pisolite ore, or both the maramamba ore and pisolite ore contained in the granulated material of the sintering raw material before drying. When it contains, as a total ratio, 20-100 mass% (dry) is preferable. If the amount is less than 20% by mass, the ratio of iron ore as a sintering raw material is too small, and the productivity is deteriorated. Therefore, it is necessary to add a large amount of iron ore in a subsequent step. When the proportion of iron ore is large, other raw materials necessary for sintering are added in the post-process.

  Moreover, as a binder added to the sintering raw material containing an iron ore, it is preferable to use at least 1 or more types among a polyacrylic acid type dispersing agent, quicklime, and lignin from the point of improving granulation property, for example. In particular, when porous iron ore such as maramamba ore is included in the sintering raw material, sodium polyacrylate is more preferable.

  Hereinafter, an embodiment of a pretreatment method of a sintering material according to the present invention will be described with reference to the drawings. FIG. 1, FIG. 2 and FIG. 5 show an example of a process flow used in the pretreatment method of a sintering raw material according to the present invention. 3, 4, and 6 show a schematic configuration example of equipment used in the sintering raw material pretreatment method according to the present invention. FIG. 7 is a schematic diagram showing a schematic configuration of a fluidized bed dryer (also referred to as a fluidized bed dryer) used in the sintering raw material pretreatment method according to the present invention.

<First Embodiment>
In the pretreatment of the sintering raw material according to the present invention for producing a sintered ore, as shown in FIG. 1, the first embodiment includes a sintering raw material 21 containing moisture, a kneading step 22, and granulation. A part of the sintered raw material that has been processed in the order of step 23 and drying step 24 and dried in the drying step is returned to the water-containing sintered raw material 21 or kneading step 22, and the kneading step 22 or granulation The moisture content of the sintering raw material in step 23 is adjusted.

  By returning the sintered raw material after drying, even when the moisture content of the sintered raw material 21 containing moisture is high, the moisture content of the raw material during kneading and granulation can be adjusted to an appropriate value.

  Here, the kneading step 22 includes a kneading machine, a conveying device for the sintering raw material before and after the kneading machine, a charging / discharging device for the sintering raw material to the kneading machine, and a binder and moisture adding device as required. It is a waste.

  In addition to the granulator, the granulation step 23 includes a conveying device for the sintered raw material before and after the granulator, an apparatus for charging and discharging the sintered raw material to the granulator, and an apparatus for adding moisture and binder as necessary. It is a waste.

  The drying step 24 includes a dryer, a granulated product (also referred to as pseudo particles) of the sintered raw material before and after the dryer, and a device for feeding and discharging the granulated product to the dryer.

  As a method for returning a part of the sintered raw material after drying, for example, a sieve is provided in the subsequent stage of the drying process (not shown), and the fine powder under the sieve is transferred by a belt conveyor, a bucket conveyor, or an air current conveyance. Return. Of course, it is possible to return a part of the sintered raw material after drying at random without classifying fine powder and coarse powder, but after pre-processing for transporting it to the subsequent process such as the sintering process. In order to improve the productivity of sintered ore without including fine powder that impedes air permeability in the sintering machine, it is preferable to perform sieving and return the fine powder.

<Second Embodiment>
Next, as shown in FIG. 2, the second embodiment according to the present invention is a mode in which a pulverization step 25 is provided before the kneading step 22 in the first embodiment. Other steps are the same as in the first embodiment, but a part of the sintered raw material after drying in the drying step returns to the sintered raw material 21 containing moisture, the pulverizing step 25, or the kneading step 22. Then, the moisture content of the sintering raw material in the pulverization step 25, the kneading step 22, or the granulation step 23 is adjusted.

  By returning the sintered raw material after drying, even when the moisture content of the sintered raw material 21 containing moisture is high, the moisture content of the raw material during pulverization, kneading, and granulation can be adjusted to an appropriate value. It becomes.

  In this embodiment having a pulverization step, if the sintered raw material to be pulverized includes coke powder and anthracite as the fuel source in the sintering, these finely pulverized fuel sources are burnt rapidly during sintering. Since the temperature control becomes difficult, the fuel source is preferably added after pulverization.

  The pulverization step 25 includes, in addition to the pulverizer, a conveying device for the sintered raw material before and after the pulverizer, an apparatus for charging and discharging the sintered raw material to the pulverizer, an apparatus for adding moisture as required.

  Here, the equipment used in each step will be described.

  As the kneading machine, a Redige mixer, an Eirich mixer, a Henschel mixer, a ball mill, or the like can be used.

  As the granulator, a drum mixer, a disk pelletizer, or the like can be used. In addition, since a Redige mixer, an Eirich mixer, and a Henschel mixer also have a granulation function, it is also possible to perform a kneading | mixing process and a granulation process by 1 process. However, since the yield of the granulated material is deteriorated as compared with the case where the granulation step is separately divided, it is more preferable to perform the two steps separately.

  As the pulverizer, a roller press which is a biaxial roll type compression pulverizer, a ball mill, or the like can be used. Since the ball mill also has a kneading function, the pulverization step and the kneading step can be performed in one step. However, it is better to use a roller press because of the ease of granulating the sintered raw material, especially when the raw material contains porous iron ore such as maramamba ore. More preferably, a roller press is used, and the pulverization step and the kneading step are performed in two parts.

  As the dryer, a fixed bed dryer such as a band dryer, a moving bed dryer such as a saddle type (see, for example, FIG. 3 of JP-A-6-145822), a fluidized bed dryer using gas, and the like can be used. it can.

  FIG. 3 shows a schematic configuration example of equipment used in the sintering raw material pretreatment method according to the present invention shown in the process flow example of FIG.

  In this configuration example, a storage tank 61 for moisture-containing sintered raw material, a conveying device 62 for conveying the sintered raw material containing moisture cut out from the storage tank 61 to a subsequent stage, and a kneader 63. The granulator 64 and the fluidized bed dryer 65a are arranged in this order. When kneading by the kneading machine 63, it is preferable to add a binder to the sintering raw material in order to improve the strength of the granulated product. As a drying process, in addition to the fluidized bed dryer 65a for fluidizing and drying the pseudo particles granulated with hot air gas, a dust collector 65b for collecting dust (fine powder) accompanied with the exhaust gas is provided and collected. The dried dust (fine powder) is returned before the kneader by the return device 66a (the returned dry dust is also called return powder). The sintered raw material (fine powder) after drying is in an equilibrium moisture content state with a moisture content of approximately 0% by mass.

  Moreover, in this structural example, the moisture meter 67a which measures the raw material water | moisture content after being cut out from the storage tank 61 of the sintering raw material containing a water | moisture content, the sintering raw material 21 cut out from the storage tank 61, and return powder | flour Is further provided with a moisture meter 67b for measuring the raw material moisture after joining. Instead of the moisture meter 67b, the moisture meter may be installed immediately before the kneader 63 or immediately after the granulator 64, or a plurality of moisture meters may be installed.

  In addition to measuring the moisture content of the sintered raw material 21 containing the water cut out from the storage tank 61 by these moisture meters, the moisture of the sintered raw material before or after the kneader 63 in the kneading step 22 Or the moisture content of the sintered raw material before or after the granulator 64 in the granulation step 23 so that the moisture content measured in the kneading step or the granulation step is within the target moisture content range. In addition, the return amount of the sintered raw material after drying is adjusted. The target moisture content varies depending on the type of sintering raw material, the type of kneader, and the type of granulator, and thus is set as appropriate.

  At this time, in addition to the return amount of the sintered raw material after drying, the amount of the sintered raw material 21 containing moisture cut out from the storage tank 61 is also adjusted together, and the processing of the sintered raw material processed by the kneader 63 is performed. It is preferable to adjust the amount to a target processing amount or an amount within the processing capacity range of the kneader 63. For example, when the moisture content of the sintered raw material 21 containing moisture is high, the amount of return of the sintered raw material after drying is increased, and the amount of cut out of the sintered raw material 21 containing moisture from the storage tank 61 is reduced and kneaded. The total amount of sintered raw material conveyed to the machine is adjusted so as to keep a predetermined value (target processing amount).

  Further, the moisture content is measured continuously or intermittently, and the return amount of the sintered raw material after drying is sequentially adjusted in conjunction with the time-dependent change of the moisture content of the sintered raw material 21 containing moisture. More preferably.

  In addition, when the amount of return of the sintered raw material after drying necessary for moisture adjustment is not enough for the amount of dust (fine powder) collected by the dust collector 65b, the granulated material (pseudo-pseudo) dried by the fluidized bed dryer 65a is used. Part of the particles can also be returned by the return device 66b and used for moisture adjustment. Further, as another means, it is possible to reduce the classified particle size by increasing the fluidizing gas flow rate in the fluidized bed dryer 65a, and to increase the amount of dust accompanying the exhaust gas. Since it is not necessary to install two systems, it is preferable.

  FIG. 4 shows a schematic configuration example of equipment used in the sintering raw material pretreatment method according to the present invention shown in the process flow example of FIG.

  3 is different from FIG. 3 in the example of the schematic configuration of this facility. 1) A part of the return powder from the dust collector 65b or the granulated product (pseudo particles) from the fluidized bed dryer 65a is once stored in the storage tank 69 for the return sintered raw material. And 2) adding a pulverizer 68 to the front stage of the kneader 63.

  By providing the return sintering raw material storage tank 69, the amount of return powder or the like to be charged into the pulverizer 68 can be increased more than the return powder recovery flow rate (almost constant value). As a result, even when the moisture content of the sintering raw material 21 containing moisture suddenly rises, the amount of cut out of the return sintering raw material from the storage tank 69 is temporarily increased, so that targeted sintering in the subsequent process is achieved. The moisture content of the raw material can be adjusted.

  In addition, also when providing the storage tank 69 of a return sintering raw material like the example of an equipment schematic structure of FIG. 4, moisture adjustment is possible by the method similar to FIG. For example, when the amount of cut out of the return sintered raw material from the storage tank 69 is sequentially adjusted in accordance with the target moisture content, the sintered raw material 21 containing the water from the storage raw material 61 of the sintered raw material containing water The amount of cut out is also adjusted and adjusted so that the total of the return sintered raw material and the water-containing sintered raw material 21 is within the processing capacity in the pulverization process, kneading process, granulation process, and drying process. It is preferable to do. Furthermore, it is more preferable to adjust so that it may become the set processing amount (target processing amount) in these processes.

  In addition, even when the pulverization, kneading and granulation are within the proper moisture range, if the moisture content of the sintered raw material changes rapidly, the proper processing may not be performed. In the case where the return sintering raw material storage tank 69 is provided as in the case of the schematic configuration, even if the moisture content of the sintering raw material containing moisture changes abruptly, the above moisture adjustment method is used to gradually increase the moisture content. It is more preferable to adjust the target value (range) by changing the rate.

  That is, when the moisture content of the sintered raw material containing moisture changes, the moisture content of the sintered raw material being adjusted in the pulverization process, kneading process, or granulation process maintains the moisture content before being affected by the change. Thus, the amount of stored sintered raw material used after drying, or the amount of stored sintered raw material used after drying and the processing amount of sintered raw material containing moisture are adjusted, and then before the pulverization step or kneading The moisture content of the sintered raw material before the process is such that the moisture content is determined by the balance between the processing amount of the sintered raw material containing the moisture after the moisture content change and the return amount of the sintered raw material after drying to return. In addition, the amount of stored sintered raw material used after drying, or the amount of stored sintered raw material used after drying, in the direction to make the amount used of the stored sintered raw material after drying equal to the return amount. Continuously or intermittently changing the processing amount of sintering raw materials containing water More preferable.

  In addition, after the moisture content of the sintering raw material reaches a moisture content determined by a balance between the processing amount of the sintering raw material containing moisture after the moisture content change and the return amount of the sintered raw material after drying to return. Since the storage amount of the sintered raw material after drying in the return sintered raw material storage tank 69 is reduced, the storage tank 69 temporarily returns the return amount to the storage tank 69 so as to restore the stored amount. It is preferable to slightly reduce the cut-out amount so as not to affect the proper processing in the subsequent process, so that the storage amount of the sintered material after drying in the return sintered material storage tank 69 is restored.

  Here, a specific example using the equipment of FIG. 4 will be described below. It is assumed that the moisture content in each moisture meter is measured continuously or periodically (the moisture content of the sintered raw material in the return sintered raw material storage tank 69 is 0% by mass due to the dry powder. far).

The moisture content of the sintered raw material containing water is 8% by mass, and the ratio of the amount of cut out of the return sintered raw material from the storage tank 69 is 10% by mass with respect to the total sintered raw material at the time of kneading (the return amount and the cut amount are the same amount). And the sintering raw material in the storage tank 69 is preferably as close as possible to the maximum storage amount), the proper moisture content in the kneading step is 8 to 10% by mass (the best yield after granulation), When kneading is normally performed at a moisture content of 8.5% by mass (addition of moisture at the time of kneading), when the moisture content of the sintered raw material containing moisture suddenly increases to 11% by mass due to heavy rain or the like,
(1) First, the ratio of the amount of the return sintered raw material cut out from the storage tank 69 is increased from 10% by mass to 30% by mass with respect to the total sintered raw material at the time of kneading, and (2) moisture at the time of kneading The addition is stopped or the addition amount is reduced, and (3) the moisture content during kneading is kept at 8.5% by mass. (4) Next, the cutting amount is gradually reduced so that the ratio of the cutting amount of the return sintered raw material from the storage tank 69 becomes 30% by mass to 10% by mass with respect to the total sintered raw material at the time of kneading. 5) The moisture content at the time of kneading when the ratio of the amount of cut out from the storage tank 69 becomes the original 10% by mass with respect to the entire sintered raw material at the time of kneading is suppressed within the range of the appropriate moisture content (for example, results) 9.5% by mass).

  The speed at which the amount of cut out from the storage tank 69 in (4) is gradually reduced depends on the type of the sintering raw material and the characteristics of the kneader, granulator, etc., and is thus set as appropriate. It is preferable to clarify the appropriate speed range by a test in advance.

  If the moisture content at the time of kneading exceeds the range of the appropriate moisture content, the ratio of the amount of cut out from the storage tank 69 is 10 mass relative to the total sintered raw material at the time of kneading so that it falls within the appropriate range. Adjust as over%.

  Since the sintering raw material in the storage tank 69 is reduced by the above operation, the return amount with respect to the cutout amount is increased thereafter, and the amount of the sintering raw material in the storage tank 69 is changed to the original storage amount before the operation. return. When a fluidized bed dryer is used as the dryer, the return amount can be easily increased by increasing the fluidizing gas flow rate as described above.

  In addition, since the fluctuation | variation of the moisture content at the time of kneading | mixing is restrained to the fluctuation | variation within 1.5 mass%, since appropriate management in each process process is easy and it can process, without reducing productivity. Preferred (in the above example, it is only 1% increase from 8.5 to 9.5% by mass). For this purpose, in normal processing, it is preferable to set an appropriate moisture content at the time of kneading or granulation on the lower side of the appropriate range.

<Third Embodiment>
Next, in the third embodiment according to the present invention, the sintered raw material of the granulated product after the treatment in the first embodiment or the second embodiment is subjected to a pretreatment in another step. After mixing with the raw material, sintering is performed.

  In the present embodiment, raw materials that are difficult to granulate, such as Malabamba ore and pisolite ore, are treated as moisture-containing sintered raw materials in the first and second embodiments to improve the strength of the granulated product, and hematite Sintered raw materials that are easily granulated, such as ore, are processed by a conventional technique in a separate process to improve the processing efficiency, and then both are mixed and processed in the sintering process.

  For example, FIG. 5 shows a case in which the sintered raw material of the granulated product treated in the first embodiment is mixed with the sintered raw material after granulated in another step.

  The example of FIG. 5 is a case where, for example, another sintering raw material 21b is processed in two granulation steps 23b and 23c as another step, but usually one granulation step may be used. When the granulation time is insufficient only once, it is processed in two granulation steps as shown in FIG.

  The mixing destination of the sintered raw material processed in the embodiment according to the present invention is not limited to the example of FIG. 5, and is sent to the subsequent stage of the granulating step 23 b, and together with other sintered raw materials 21 b in the granulating step 23 c. You may granulate.

  FIG. 6 shows a schematic configuration example of equipment used in the sintering raw material pretreatment method according to the present invention shown in the process flow example of FIG.

  The example of FIG. 6 is substantially the same as that of FIG. 3 with respect to the pretreatment step of the sintering raw material containing moisture before mixing with the sintering raw material pretreated in another step. In this example, the exhaust gas of the sintering cooler 71 is sent to the fluidized bed dryer 65a by the blower 72 and used as hot air necessary for fluidized drying in the fluidized bed 65a. Thereby, it is not necessary to provide new equipment such as a hot air generating furnace, and the drying cost can be reduced.

  Here, the details of the fluidized bed dryer will be described.

  As shown in FIG. 7, the fluidized bed dryer supplies a supply hopper 2 for accumulating the granulated material 11 before drying and the granulated material 11 accumulated in the supply hopper 2 to the dryer main body 1. Supply device (screw feeder) 3, a hot air furnace (or duct burner) 7 and a blower 8 for supplying hot air to the dryer main body 1.

  A dispersion plate 4 is disposed below the dryer body 1, and an air box 6 is formed below the dispersion plate 4. Hot air supplied from the hot stove 7 is guided into the wind box 6, passes through the dispersion plate 4, and is blown into the free board portion 9.

  A discharge device 5 for extracting the granulated product 13 after drying is provided at the lower side portion of the dryer body 1. In addition, an exhaust pipe 10 connected to a dust collector (see FIGS. 3, 4, and 6) is provided on the upper portion of the dryer body 1.

  In this fluidized bed dryer, the granulated material 11 is supplied from the supply hopper 2 to the free board unit 9. The granulated material 11 charged into the free board portion 9 is dried while forming a fluidized bed 12 by the gas sent from the hot stove 7. Then, the dried granulated product 13 is discharged to the outside of the dryer main body 1 by the discharge device 5. Further, the exhaust gas from the exhaust pipe 10 is guided to a dust collector (see FIGS. 3, 4, and 6) to collect fine powder. The fine powder is guided to a kneader (see FIGS. 3, 4, and 6) and reused in the granulation process.

  An embodiment will be described based on the specific configuration of the sintering equipment used in the sintering raw material pretreatment method according to the present invention in FIG.

  FIG. 8 is a schematic diagram showing a specific configuration of a sintering facility used in the sintering raw material pretreatment method according to the present invention.

  As shown in FIG. 8, the storage tank has first to fourth storage tanks 51 a, 51 b, 51 c, 51 d for storing sintered raw materials containing moisture conveyed from the raw material yard, and after drying in the drying process. It consists of the 5th storage tank 51e which returns and uses a part of sintering raw material. Each of the first storage tank 51a to the fifth storage tank 51e has a built-in cutting device that can adjust the cutting speed of the sintered raw material in the tank.

  The 1st belt for conveying the sintering raw material stored in each storage tank 51a, 51b, 51c, 51d, 51e below the exit of the 1st-5th storage tank 51a, 51b, 51c, 51d, 51e. A conveyor 52 is provided. A second belt conveyor 53 for conveying the sintered raw material to the pulverizer is disposed on the outlet side of the first belt conveyor 52. Furthermore, a fourth belt conveyor 55 for returning the dried sintered raw material to the moisture-containing sintered raw material is disposed on the second belt conveyor 53.

  A pulverizer 56, a kneader 57, a granulator 58, and a dryer 59 are arranged in this order as devices used in the processing step on the downstream side of the second belt conveyor 53.

  The pulverizer 56 was a roller press pulverizer, the kneader 57 was a Redige mixer, the granulator 58 was a drum mixer, and the dryer 59 was a fluidized bed dryer.

  In addition, a dust collector (not shown) is connected to the exhaust gas outlet of the dryer 59 so that fine powder (dust) collected by the dust collector is returned to the fifth storage tank 51e. A part of the sintered raw material that is a granulated product (pseudo particle) after the drying treatment is conveyed to the second belt conveyor 53 via the fourth belt conveyor 55 as necessary.

  In addition, moisture meters (not shown) are provided on the outlet side of each of the first storage tank 51a to the fourth storage tank 51d and on the outlet side of the second belt conveyor 53, respectively. Instead of the moisture meter on the outlet side of the cutting device, a moisture meter may be provided in the middle of the conveyance path for conveying the sintered raw material from the raw material yard. As this moisture system, for example, an infrared absorption moisture meter, a quartz oscillation moisture meter, a neutron moisture meter, or the like can be used.

  Thus, in the sintering raw material pretreatment method according to the present invention, the moisture value is adjusted by circulating at least part of the raw material in the middle of the treatment process.

<Adjustment of moisture value>
Next, adjustment of the moisture value in the sintering raw material pretreatment method according to the present invention will be described based on specific examples.

  In the embodiment described below, the cut amount and moisture value from the first to fourth storage tanks 51a, 51b, 51c, 51d, the cut amount and moisture value from the fifth storage tank 51e, the second belt conveyor 53, The relationship between the passage of time and the moisture value will be described with respect to the moisture value of the sintered material conveyed by the above and the circulation amount of the sintered material circulated and used by the third belt conveyor 55.

  In the following Table 1, each storage with respect to the type and moisture content of the sintering raw material stored in each of the first to fourth storage tanks 51a, 51b, 51c, 51d and the total cutout amount of the first to fourth storage tanks. The ratio of the amount of tank cut out (normal time) is shown. Table 2 shows the moisture content of the sintering raw material of each storage tank and the ratio of the cut-out amount of each storage tank to the total cut-out amount of the first to fourth storage tanks when the water content becomes high due to heavy rain. Indicates. About the return sintered raw material after drying in the 5th storage tank 51e, the moisture content is an equilibrium moisture content (almost 0%).

  Moreover, the target value of the moisture content of the sintered raw material during the processing after the pulverizer 56 (the measured moisture value on the second belt conveyor 53 outlet side) is set to 5 to 9%.

Here, the moisture content of iron ore tends to be higher than the moisture content of limestone and serpentinite. This is because iron ore is sprayed with water for the purpose of preventing dust generation in the mountains, and limestone and serpentine. The rock is due to the early replacement from the raw material yard. As described above, since the moisture content varies depending on each sintering raw material, the moisture content was measured for each storage tank.
Example 1
<When the return amount of the dried sintered material is constant>
First, the relationship between the passage of time and the moisture value when the return amount of the dried sintered raw material is adjusted to be constant will be described. FIG. 9 is a time chart showing the relationship between the passage of time and the moisture value when the return amount is constant.

  When the return amount is constant, as shown in FIG. 9, in a normal processing state, the target moisture content of the sintered raw material at the time of processing after the pulverizer 56 (measurement of moisture on the outlet side of the second belt conveyor 53). Value) is set to 5 to 9%, and the sintered raw material (moisture content 0 mass%) dried at 50 t / h from the fifth storage tank 51e is cut out, and the first to fourth storage tanks 51a, 51b, 51c, 51d to 150t are cut out. Since the sintered raw material containing moisture (average moisture content 7.7 mass%) is cut out at / h, the average moisture value of the sintered raw material conveyed by the second belt conveyor 53 is 5.9 mass%, which is stable. And keep the target value.

  However, here, when the average moisture value of the sintered raw material supplied from the raw material yard rises to 11% by mass due to heavy rain, it is reflected in the sintered raw material charged into the processing step, as shown in FIG. The average moisture value of the sintered raw material conveyed by the belt conveyor 53 increases to 8.5%.

  By returning the sintered raw material after drying, even if the average moisture content of the sintered raw material containing moisture exceeds 11%, which is 5% to 9% of the target value, the moisture content after the pulverization step is set to the target value. It was able to fit within the range.

However, in this case, although it is within the range of the target value, the moisture content rapidly increased, so the moisture value of the sintering raw material charged into the pulverizer 56 increased rapidly, and was appropriate during pulverization, kneading, granulation, and drying. Moisture management could not be performed temporarily, and granulation efficiency was lowered for about 2 hours, resulting in lower productivity.
(Example 2)
<Sequential moisture adjustment>
With reference to FIG. 10, the pre-processing method of the sintering raw material which concerns on Example 2 is demonstrated. FIG. 10 is a time chart showing the relationship between the passage of time and the moisture value in Example 1 in which moisture adjustment is performed.

  The target value (moisture measurement value on the outlet side of the second belt conveyor 53) of the sintered raw material during the processing after the pulverizer 56 is adjusted to 5 to 9%.

  As shown in FIG. 10, when the moisture value of the sintering raw material supplied from the raw material yard increases due to heavy rain, the pretreatment method of the sintering raw material according to Example 2 is supplied from the fifth storage tank 51e. After the supply amount of the sintered raw material after the increase is once increased, the supply amount of the sintering raw material supplied from the first to fourth storage tanks 51a, 51b, 51c, 51d is once decreased while being gradually decreased. After that, it is gradually increased.

  Other conditions are the same as in the first embodiment.

  Specifically, as shown in FIG. 10, in the initial processing state, the sintered raw material is cut out from the fifth storage tank 51e at 50 t / h, and the first to fourth storage tanks 51a, 51b, 51c, 51d to 150t. Since the sintering raw material containing moisture is cut out at / h, the moisture value of the sintering raw material conveyed by the second belt conveyor 53 is 5.9%. In this case, the moisture value of the sintered raw material after drying supplied from the fifth storage tank 51e is 0%, and the sintering raw material supplied from the first to fourth storage tanks 51a, 51b, 51c, 51d The moisture value is 7.7%.

  Here, when the moisture value of the sintered raw material supplied from the raw material yard rises to 11% due to heavy rain, the sintered raw material conveyed by the second belt conveyor 53 is reflected in the sintered raw material charged into the treatment process. Increases the moisture value. Therefore, after once increasing the supply amount of the sintered raw material after drying supplied from the fifth storage tank 51e, it is gradually decreased and supplied from the first to fourth storage tanks 51a, 51b, 51c, 51d. The supply amount of the sintering raw material containing moisture is once reduced and then gradually increased. For this reason, the moisture value of the sintering raw material conveyed by the 2nd belt conveyor 53 rises gradually, and finally becomes 8.5%.

  In Example 2, since the moisture adjustment is sequentially performed according to the above-described procedure, the moisture value of the sintering raw material charged into the pulverizer 56 does not rise rapidly, and appropriate moisture management can be performed. Thus, proper management during pulverization, kneading, granulation, and drying was possible, and the productivity was not deteriorated, and stable treatment was possible.

  In Example 2, the moisture was gradually and gradually adjusted. However, when the moisture was adjusted step by step within a range not adversely affecting the subsequent processes after the pulverization process (5.9 → 6. 5 → 7.2 → 7.9 → 8.5%), the moisture value of the sintering raw material charged into the pulverizer 56 does not rise rapidly, and appropriate moisture management can be performed. Appropriate management during kneading, granulation, and drying was possible, and the productivity was not deteriorated and could be treated stably.

  In addition, the apparatus used in the pretreatment method of the sintering raw material according to the present invention is not limited to the one described above, and in the pretreatment for drying the sintering raw material, kneading / granulation / drying or crushing / kneading / granulation Any device may be used as long as it can be dried and added to other raw materials.

  The present invention is useful when producing sintered ore mainly using iron ore having a high crystallization water content as a raw material, but can be widely applied also when pre-treating a general sintered raw material.

It is a figure which shows the example of a process flow used for the pre-processing method of the sintering raw material which concerns on this invention. It is a figure which shows the example of a process flow used for the pre-processing method of the sintering raw material which concerns on this invention. It is a figure which shows the schematic structural example of the equipment used for the pre-processing of the sintering raw material which concerns on this invention. It is a figure which shows the schematic structural example of the equipment used for the pre-processing of the sintering raw material which concerns on this invention. It is a figure which shows the example of a process flow used for the pre-processing method of the sintering raw material which concerns on this invention. It is a figure which shows the schematic structural example of the equipment used for the pre-processing of the sintering raw material which concerns on this invention. It is a schematic diagram which shows schematic structure of the fluidized bed dryer used for the pre-processing of the sintering raw material which concerns on this invention. It is a schematic diagram which shows the specific structure of the sintering equipment used with the pre-processing method of the sintering raw material which concerns on this invention. It is a time chart which shows the relationship between time passage and the moisture value in the case of Example 1 with constant return amount. It is a time chart which shows the relationship between the time passage in Example 2 which performs a water | moisture content adjustment sequentially, and a moisture value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dryer main body 2 Supply hopper 3 Supply apparatus (screw feeder)
4 Dispersing plate 5 Discharge device 6 Wind box 7 Hot air furnace (duct burner)
8 Blower 9 Free board part 10 Exhaust pipe 11 Granulated product before drying 12 Fluidized bed 13 Granulated product after drying 21, 21a, 21b Sintered raw material containing moisture 22 Kneading process 23, 23a, 23b, 23c Granulating process 24 drying process 25 grinding process 26 sintering process 51a first storage tank 51b second storage tank 51c third storage tank 51d fourth storage tank 51e fifth storage tank 52 first belt conveyor 53 second belt conveyor 55 third belt conveyor 56 grinder 57 kneading machine 58 granulator 59 dryer 61 storage tank for moisture-containing sintered raw material 62 transport device 63 kneader 64, 64a, 64b, 64c granulator 65a fluidized bed dryer 65b dust collector 66a, 66b, 66c, 66d Return device 67a, 67b, 67c, 67d Moisture meter 68 Pulverizer 69 Return sintered raw material storage tank 7 0 Sintering machine 71 Sintering cooler 72 Blower

Claims (16)

  A sintered raw material containing moisture is processed through a kneading step, a granulating step, and a drying step in this order, and a part of the sintered raw material after drying in the drying step is used as the sintered raw material containing the moisture or the kneading step. Returning to the process, adjusting the moisture content of the sintered raw material in the kneading step or the granulating step, a pretreatment method for a sintered raw material.   A sintering raw material containing moisture is processed through a pulverization step, a kneading step, a granulation step, and a drying step in this order, and a part of the sintering raw material after drying in the drying step is used as a sintering raw material containing the moisture. Returning to the pulverizing step or the kneading step, the moisture content of the sintered raw material in the pulverizing step, the kneading step, or the granulating step is adjusted.   The drying in the drying step is fluidized bed drying with gas, and the sintering raw material powder accompanying the exhaust gas after flowing is recovered, and the recovered powder is used as a part of the sintering raw material after the drying, 3. The sintering raw material pretreatment method according to claim 1, wherein the process returns to the sintering raw material containing moisture, the pulverization step, or the kneading step.   The moisture content of the sintered raw material containing the moisture, the moisture content of the sintered raw material in the kneading step, or the moisture content of the sintered raw material in the granulation step are measured, and the kneading step or the granulation step The return of the sintered raw material after drying, or the return of the sintered raw material after drying and the processing of the sintered raw material containing the water, so that the moisture content measured in step 1 falls within the target moisture content range The pretreatment method for a sintering raw material according to any one of claims 1 to 3, wherein the amount is adjusted.   The moisture content of the sintered raw material containing the moisture is measured so that the moisture content is measured continuously or intermittently, and the moisture content measured in the kneading step or the granulation step is within the moisture content range of the target value. According to the change in the rate, the return amount of the sintered raw material after drying, or the return amount of the sintered raw material after drying and the processing amount of the sintered raw material containing the moisture are sequentially adjusted. The pre-processing method of the sintering raw material of Claim 4.   The returned sintered raw material after drying is temporarily stored, and the stored dried sintered raw material is replaced with the returned sintered raw material after drying, the pulverizing step, the kneading step, or the manufacturing It uses for adjustment of the moisture content of the sintering raw material in a granule process, The pretreatment method of the sintering raw material of any one of Claims 1-5 characterized by the above-mentioned. When the moisture content of the sintered raw material containing moisture changes, the moisture content of the sintered raw material being adjusted in the pulverization step, the kneading step, or the granulation step is affected by the change. To adjust the amount of the stored sintered raw material after drying, or the amount of the stored sintered raw material after drying and the processing amount of the sintered raw material containing moisture,
Then, the moisture content of the sintered raw material before the pulverization step or the kneading step is a processing amount of the sintered raw material containing the moisture after the moisture content change, and a return amount of the sintered raw material after the drying to return So that the moisture content is determined by the balance of
In the direction to make the usage amount of the stored sintered raw material after drying the same amount as the return amount,
The usage amount of the stored sintered raw material after drying, or the usage amount of the stored sintered raw material after drying and the processing amount of the sintered raw material containing moisture are changed continuously or intermittently. The pretreatment method for a sintering raw material according to claim 5, wherein the sintering raw material is pretreated.   The sintering raw material pretreatment method according to any one of claims 1 to 7, wherein a binder is added in the kneading step or the granulation step.   The sintering according to any one of claims 1 to 8, wherein the moisture-containing sintering raw material contains 20 to 100% by mass (dry) of Malabamba ore, Pisolite ore, or Mara Mamba ore and Pisolite ore. Raw material pre-processing method.   The pretreatment method for a sintering material according to claim 8 or 9, wherein the binder is a polyacrylic acid-based dispersant or quicklime.   A storage tank of moisture-containing sintered raw material, a conveying device for conveying the sintered raw material cut out from the storage tank, a subsequent kneader, a granulator, and a dryer, and dried by the dryer And a return device for returning a part of the dried product to the conveying device or the kneader.   A storage tank for moisture-containing sintered raw material, a storage tank for returned sintered raw material, a conveying device for conveying both sintered raw materials cut out from both storage tanks, a kneader and a granulator at the subsequent stage And a return device for returning a part of the dried product dried by the dryer to the storage tank of the returned sintered raw material. .   The storage tank of the sintering raw material containing the moisture, or the storage tank of the sintering raw material containing the moisture and the storage tank of the sintered raw material to be returned can control the cutting amount of the raw material. Or the pre-processing apparatus of the sintering raw material of 12.   13. The sintering raw material pretreatment device according to claim 11 or 12, further comprising a pulverizer at a subsequent stage of the conveying device and further having the kneader at a subsequent stage.   The dryer is a fluidized bed dryer having a function of collecting and collecting fine powder entrained in the exhaust gas after flowing, and the return device is a return device that returns the collected fine powder. 14. The sintering raw material pre-processing apparatus according to claim 11, wherein the sintering raw material pre-processing apparatus is provided.   Moisture measurement device for sintered raw material containing moisture, and moisture measurement of the sintered raw material in at least one of the kneading machine inlet side, the kneader outlet side, the granulator inlet side, or the granulator outlet side The pretreatment apparatus for sintering raw materials according to any one of claims 11 to 14, further comprising an apparatus.

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