JP2016141826A - Facility for granulating hardly granulable powder material using quick lime as binder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a granulation facility capable of economically producing a granulation material of hardly granulable powders having the strength sustaining severe handling in a conveyance process while suppressing occurrence of moisture and dust due to high-volume addition of quick lime as a binder.SOLUTION: A granulation facility comprises: a primary granulator 2 supporting a drum 3 with built-in rod 4 for compaction by a suspension unit 7; a dispersion unit 8 dispersing a primary granulation material discharged from the drum 3; a secondary granulator 10 receiving the primary granulation material supplied via the dispersion unit into numerous launders 10b to rolling-granulate; and a sprinkler 9 replenishing moisture to a secondary granulation material. The primary granulator 2 is configured by mounting a vibration source 5 which vibrates the drum 3 by vibrating to a vibration acceleration of 6G or more at a maximum part at a position positioning disproportionately to a raw material charging port side from the drum center of a drum outer periphery. The secondary granulator 10 is used as a granulation facility connected to the drum 3 to be vibrated by the vibration source 5. The granulation of hardly granulable powders needing the addition of quick lime of 3% or more in a mass ratio is carried out using the above facility.SELECTED DRAWING: Figure 2

Description

  This powder granulation that uses raw apatite in a large amount as a binder makes it possible to produce a granulated product that has high granulation strength and is difficult to disintegrate while suppressing generation of water vapor and dust. More particularly, the present invention relates to a granulation facility that employs a vibration granulator having a simple structure.

  As a specific example of powder granulation using raw apatite as a binder, for example, there is a sintering process of iron ore.

  Conventionally, powder is granulated in the iron ore sintering process using a powder containing fine powder as a blast furnace raw material.

  In the iron ore sintering process, the powder is granulated and sintered, and agglomerated into sintered ore having an average particle diameter of about 20 mm to be used as a blast furnace raw material.

  The sintered ore is agglomerated by burning the fuel contained in the granulated material and partially melting the granulated material with heat during combustion.

  The productivity of this sintering depends on the air permeability that ensures the combustion of fuel in the bed filled with granulate. Conventionally, granulation was performed using a drum mixer, a pan pelletizer, an Eirich mixer, etc., in order to promote combustion while obtaining air permeability and to obtain sintered ore.

  In addition, since the air permeability of the granulated product packed layer is inversely proportional to the amount of fine powder in the sintered raw material, recently, the granulated product is not granulated more than conventional granulation methods as described in Patent Documents 3 and 4 below. A vibration kneading and granulating device has been developed that enables granulation that has a small amount of fine powder and is difficult to be disintegrated and powdered at the time of conveyance. A technique for collecting and reusing the raw material that has returned to powder has also been developed (see Patent Document 1 below).

  In addition, since the granulated material is required to have a strength that can withstand handling such as transportation, among the granulated material that has undergone the granulation process and the sieving process by the vibration kneading granulator, a pseudo-particle having a low strength is sintered. There has also been a proposal to intentionally hesitate and collect it before it is introduced (see Patent Document 2 below).

  The vibratory kneading and granulating apparatus disclosed in Patent Document 3 is a primary granulating apparatus in which raw material powder is put into a container containing a large number of compacted media, and the container is subjected to circular acceleration by applying a vibration acceleration of 3G to 10G. A secondary granulator is arranged at the subsequent stage, and the granulated product supplied from the primary granulator is agglomerated by rolling at a low vibration rotational speed using a secondary granulated product that does not use a compaction medium. I have to.

  Further, Patent Document 3 discloses a secondary granulation apparatus for performing secondary granulation by dispersing and dropping flaky granulated material supplied from a primary granulation apparatus into a number of troughs provided in a wave trough. Are also disclosed.

JP 2007-547830 A JP 2012-67348 A Japanese Patent Laid-Open No. 3-166321 JP-A-5-23567

A granulated product granulated by a drum mixer, a pan pelletizer, an Eirich mixer or the like becomes particles having relatively weak strength called pseudo particles. This pseudo-particle collapses during transfer from the granulator to the conveyor and from the conveyor until it is loaded into the sintering machine through the surge hopper and raw material charging device, and part of it returns to powder. The meaning of granulation is lost.

  When the mixing ratio of the powdered raw material is increased, there is a problem that the air permeability of the sintering machine raw material packed layer is lowered to hinder combustion, and the productivity of sintering is remarkably reduced.

On the other hand, although the granulated material using the vibration kneading granulator disclosed in Patent Documents 3 and 4 has higher strength than the pseudo particles obtained by a drum mixer or the like, this type of granulator Even if it is used, it is difficult to completely eliminate the collapse of the granulated material.

  Therefore, Patent Documents 1 and 2 enable granulation without powder by collecting the collapsed powder through a sieve. However, this method requires a sieve device in addition to the granulation equipment. In addition, there is a new technical problem that the wet granulated material containing moisture must be efficiently and effectively sieved by the sieving device, and wet sieving is expensive and requires a special wave screen. It is difficult to meet that requirement.

  In addition, it is known that lime is effective as a binder for strengthening granulation for a hardly granulated powder raw material.

  As for the addition of lime, for example, quick lime (calcium oxide) is generally added in a mass ratio of about 2 to 3%. If the amount of quicklime added is increased to 3% or more, a hardly granulated raw material can be granulated. However, if a large amount of quicklime is used, the production cost becomes very high.

  In addition, the conventional granulation equipment generates a lot of heat and generates water vapor and dust. Therefore, if a special dust collector is not provided, the environment is hindered. Moreover, the addition of a large amount of quicklime greatly varies the granulation strength, and the effect of addition is not stable. It is already known that such a problem occurs.

  On the other hand, when slaked lime (calcium hydroxide) is added instead of quick lime, the problem at the time of using quick lime is solved, but slaked lime is much more expensive than quick lime.

To make a difficult-to-granulate powder raw material into a granulated product that has the strength to withstand violent handling with minimal cost increase and air permeability that guarantees stable combustion, a large amount of quick lime is added as a binder. Is considered the best option, but the addition of large amounts of quicklime is associated with the above problems.

  In recent years, in order to make effective use of resources, fine powder that has not been used in the past (such as iron-containing dust and sludge generated in concentrates and steelworks, etc., which are low-grade ore concentrate) and difficult granulation There is an increasing demand for using powder as a raw material without waste.

  However, a practical granulation facility that can reliably solve the above-mentioned problems caused by the addition of a large amount of quicklime has not yet been developed, and therefore, it has fully met the demand for effective use of resources. There is no actual situation.

  This invention is a granulating equipment (granulating apparatus) having a simple and economical structure capable of producing a granulated product having strength capable of withstanding intense handling in the conveyance process while suppressing generation of water vapor and dust due to the addition of a large amount of quicklime. It is an issue to provide.

In order to solve the above-mentioned problems, in the present invention, a hardly granulated powder (hereinafter simply referred to as powder) which is required by adding quick lime having a mass ratio of 3% or more as a binder to a drum incorporating a large number of rods. ), And the drum is vibrated circularly by applying a vibration acceleration of 6G or more at the maximum part, and the charged material in the drum is stirred, kneaded, and granulated,
Dropping the primary granulated material formed in the drum from an outlet of the drum onto a slanted bowl of a secondary granulating device integrated with the primary granulating device via a dispersing device;
A watering process for adding an appropriate amount of water to the granulated material that has fallen on the bowl of the secondary granulator,
The secondary granulator is subjected to circular vibration, and the circular vibration is performed so that vibration is damped at the lower end of the granulation flow of the vertical granule, followed by secondary granulation and powder. Was granulated.

  With this method, only the hardly granulated powder raw material in the sintered raw material is selected and granulated, and the granulated product obtained by this method and the granulated product of other powder raw material in the sintered raw material (this is It can be granulated with a conventional drum mixer) and used as a sintering raw material.

The hardly granulated powder raw material is granulated using a vibration granulation facility. In the present invention, the vibrating granulation equipment is configured as follows.
That is, a primary granulator that supports a drum containing a large number of rods for compaction with a suspension device, and has a raw material inlet, a water addition port, and an outlet of the granulated material formed in the drum;
A dispersion device for dispersing the primary granulated material discharged from the outlet of the drum in the direction of horizontal expansion;
A secondary granulator for receiving and granulating the primary granulated material supplied via the dispersing device in a number of ridges extending in the discharge direction, and a watering for supplying moisture to the granulated material for performing secondary granulation Equipped with equipment,
In the primary granulator, the vibration source that vibrates the drum at a vibration acceleration of 6 G or more at the maximum portion and circularly vibrates is positioned closer to the raw material inlet than the drum center (longitudinal middle point) on the outer periphery of the drum. The secondary granulator is integrally connected to the drum and is vibrated by the vibration source of the primary granulator.

  If the granulation equipment of this invention is used, generation | occurrence | production of the water vapor | steam and dust by the intense heat_generation | fever of quicklime will be suppressed, and it will become unnecessary to provide environmental maintenance equipment, such as a special dust collector.

  The reason for this is that the uniform atomization of quicklime progressed remarkably by sliding, friction, crushing action between the rods in the drum of the primary granulator and the crushing action between the rods. The soaking reaction that uniformly disperses in the raw material powder and turns the quick lime into slaked lime occurs efficiently, uniformly, and instantaneously in each part of the drum. For this reason, in conventional devices (drum mixers, etc.) Compared to this, the bias of local heat generation is reduced, and the heat is uniformly absorbed by the powder having a high specific heat.

  The inventors have found through experimentation that even when a large amount of quicklime is used, the heat generation and dust generation are suppressed, and a vibration kneading type granulating apparatus that can obtain the above-described effects and effects for primary granulation has been developed. did.

  In order to make difficult-to-granulate powder into a granulated product that can withstand handling, finely divided quick lime is uniformly dispersed and evenly adhered to the surface of the raw material powder (particles). It is important to intervene. By doing so, it is possible to suppress variation in strength of the granulated product.

  In this regard, granulation by the granulation facility of the present invention satisfies the requirements by utilizing the characteristics of the vibration kneading granulator. Therefore, even if the addition amount of quick lime as a binder is increased, the effect of particle bonding is stably exhibited, and a granulated product having a stable strength can be obtained.

  Furthermore, in the vibration kneading granulation in which a large amount of quicklime is added, the kneading proceeds before the decalcification reaction of quicklime is completed in the primary granulation. When the added moisture is adjusted so that the maximum bond strength can be obtained in the kneading, the moisture required for refining in the secondary granulation process is consumed, resulting in a situation where the moisture is insufficient and the high strength is ensured. It was also found by experiment that the next granulation was not possible.

  In order to solve this problem, the granulation facility of the present invention is provided with a watering device, so that water can be replenished to the granulated material to be subjected to secondary granulation, and the granulation strength is increased by the addition of the water.

  Furthermore, it was found that granulation initially prioritizes particle agglomeration, and finally rounding the surface is effective in reducing collapse during the transport process.

  In the granulation facility of the present invention, the vibration source is arranged at a position deviated from the center of the drum of the primary granulator toward the raw material inlet, and the secondary granulator integrated with the primary granulator by the vibration source. Since the granulator is also vibrated, the vibration force decreases toward the front of the granulated material in the traveling direction (exit side of the secondary granulator).

  This makes it easy to round the surface of the granulated product, and the total amount of quicklime added is higher than the amount used in conventional devices due to the synergistic effect of strengthening the bond by hydration and suppressing collapse by rounding the surface. It is possible to obtain high strength with less.

In addition, granulated by increasing the amount of quick lime input to the difficult-granulated powder, and the granulated product obtained in this way was granulated by reducing the amount of quick lime added by a conventional granulation method such as a mixer. Compared with the conventional granulation method that does not granulate by selecting difficult-granulating powder, it can be mixed with the raw material granulated material to reduce the total amount of quick lime. Can be obtained.

  In addition, since the primary granulation apparatus and the secondary granulation apparatus which have been provided separately are integrated, the structure can be simplified and the equipment cost can be reduced.

It is a perspective view which shows one form of the granulation equipment of this invention. It is a longitudinal cross-sectional view of the granulation equipment of FIG. It is a front view of the granulation equipment of FIG. It is explanatory drawing of the drum vibration in the primary granulation of the granulation equipment of FIG. 1, and the movement state of the rod in a drum. Granulation using a conventional drum mixer, granulation using a conventional two-stage vibration kneading apparatus (granulation method of Patent Document 1), granulation in which the center of the apparatus is vibrated with a primary and secondary granulation integrated type, and the present invention It is a chart which shows the comparison experiment result of granulation by the granulator of.

  Embodiments of the powder granulation method and granulation equipment of the present invention will be described below with reference to FIGS. 1 to 4 of the accompanying drawings.

  An exemplary granulation facility 1 includes a primary granulation device 2, a dispersion device 8, a sprinkling device 9, and a secondary granulation device arranged downstream of the primary granulation device 2 (frontward in the direction in which the granulated product flows). 10 are integrally combined.

  The primary granulator 2 is a vibration granulator, and a large number of rods 4 (see FIG. 2) are housed inside a drum 3 having a raw material inlet 3a, a water addition port 3b, and an outlet 3c for the granulated product. Further, a vibration source 5 for circularly vibrating the drum 3 is provided on the outer periphery of the drum 3, and the drum 3 is supported by a suspension device 7 on the gantry 6.

  3 d is a door provided at one end of the drum 3. Since the door 3d is provided with an inspection port inside the drum 3, it is provided to close the inspection port, but the inspection port is provided as necessary. Therefore, the door 3d is not essential. The drum 3 is arranged horizontally.

  The illustrated excitation source 5 is a weight type vibration motor. The excitation source 5 has a capability of allowing the drum 3 to vibrate circularly with a vibration acceleration of 6G (G is gravitational acceleration) or more, and further, the drum center on the outer periphery of the drum 3 (the midpoint in the longitudinal direction). For example, a position biased 0.03 × L or more from the center of the length L drum (primary granulator) to the raw material inlet side.

  Although the suspension device 7 is provided with an air spring (air suspension), it may be a suspension device including a spring.

  The dispersing device 8 is disposed immediately below the drum outlet 3c. When the primary granulator 2 operates the excitation source 5, the internal rod 4 rotates in the direction opposite to the rotation direction (direction A in FIG. 4) of the excitation source (weight vibration motor) 5 (FIG. 4). (B direction). The movement is an operation that combines rotation and revolution, and the powder and quicklime put into the drum 3 are pulverized and kneaded by the rod 4, but the rod 4 moves in the drum 3 because of the above movement. As shown in FIG.

  Therefore, the powder charged into the drum 3 is also pulverized, kneaded, and granulated in the same direction as the rod 4, and the granulated product after the primary granulation is discharged from the outlet 3c while being biased. .

  The biased primary granulated material is uniformly dispersed in the laterally spreading direction (the width direction of the secondary granulating device 10) and serves to supply to all of the ridges 10b of the secondary granulating device 10 on average. In the figure, it is composed of a baffle plate 8a inclined in a direction in which the position opposite to the discharge bias direction and the flow direction of the primary granulated product are lowered.

  The water sprinkling device 9 diffuses water in a mist form and sprays it downward, and replenishes the granulated product passing through the lower side (the granulated product that performs secondary granulation).

  The secondary granulating apparatus 10 is provided with a large number of ridges 10b arranged in parallel so as to form a wave shape on the inner surface of a concavely curved diaphragm 10a. The end of the upstream side is integrally connected to the drum 3 of the primary granulator 2 and is held in a hollow position by the drum 3.

  The vibration of the secondary granulator 10 is performed using the vibration source 5 of the primary granulator 2 together. As described above, the vibration source 5 of the primary granulator 2 is mounted at a position deviated from the drum center on the outer periphery of the drum 3 toward the raw material inlet 3a. One of the features of the present invention is that the primary and secondary granulation devices are conventionally configured independently, whereas the primary and secondary granulation devices are integrated, and the secondary granulation device is also primary granulation. It is in place to vibrate with the excitation source of the device.

  Since it is such a structure, when the secondary granulator 10 is vibrated by the vibration source 5, the vibration force becomes smaller toward the front side in the traveling direction of the granulated product. For example, when vibration is applied so that the maximum portion has a vibration acceleration of about 6 to 8G, the vibration acceleration near the outlet of the secondary granulation apparatus 10 is halved to about 3 to 4G. This effectively acts to round the surface of the granulated material flowing in the tub 10b.

  This secondary granulator 10 receives the replenishment of water from the watering device 9 to further advance the granulation of the primary granulated product, and improves the strength of the granulated product. At the same time, the surface of the granulated material is rounded. As a result, the parts of the granulated material that are likely to collapse (edges or protrusions that trigger the collapse) are reduced, and the collapse during handling becomes even less likely to occur.

  The exemplary vibratory granulation facility 1 configured as described above operates the excitation source 5 to cause the drum 3 to vibrate in a situation where the vibration acceleration at the maximum portion is 6G or more. In this state, granulation-target powder (for example, iron ore raw material powder) and quicklime are simultaneously fed into the drum 3 from the raw material inlet 3a of the primary granulator. The charging is performed little by little continuously.

  The addition amount of quicklime at this time shall be 3% or more (all addition amounts of this quicklime, powder, and water shall be mass ratio). However, what can be strongly granulated with quick lime at 3% or less is more effective than the conventional method according to this apparatus, and therefore this apparatus can be used if economic efficiency is realized.

  Thereafter, added water is introduced from the water addition port 3b. In consideration of absorption digestion by quick lime and the like, the amount of water added is suitably about 10 to 30% for the granulated water.

The added quick lime immediately reacts with water by the addition of this water, but since the pulverization and kneading by the rod 4 in the drum 3 is powerful, almost all of the reaction heat is absorbed by the powder ( If the powder is an iron ore raw material with a high specific heat coefficient, heat absorption will proceed more effectively)
The Therefore, although the temperature of the charged powder slightly increases, the generation of water vapor and dust can be suppressed.

  This makes it possible to omit the installation of environmental maintenance equipment such as a dust collector.

  In addition, when granulated powder with a large amount of quick lime is added using an existing granulator such as a drum mixer, the massive quick lime is heated by causing a severe deconcentration reaction locally, and steam is generated at the same time. It turns out that the surrounding dust is rolled up.

  According to the primary granulation apparatus of the present invention, the problem does not occur.

In the primary granulator 2, the quicklime introduced into the drum 3 is atomized by the action of the rod 4 that moves circularly, and is uniformly dispersed and adheres uniformly to the surface of the powder. Therefore, the intercalation between quick lime powder particles is ensured, and a granulated product in which the bonding between the particles is stable is obtained. As a result, variation in the strength of the granulated product is reduced, and a granulated product having a high strength is obtained.

  Next, the powder charged in the drum 3 is stirred, kneaded and granulated in the drum 3 to become a primary granulated product and falls from the outlet 3c of the drum. The time from the introduction of the powder into the drum 3 to the removal of the primary granulated material from the drum was about 5 to 10 minutes.

  The primary granulated material discharged from the drum 3 falls on the baffle plate 8a of the dispersing device and rolls on the baffle plate 8a, or spreads sideways by sliding, and after the unevenness is leveled, It falls into each basket 10b on average.

  The granulated product transferred to the secondary granulation apparatus 10 is in a situation where the water necessary for soaking in the secondary granulation process has already been consumed and the entire water is insufficient. By replenishing moisture, the lack of moisture in the granulated product that is subjected to secondary granulation is eliminated, and the bonding of the particles is strengthened to increase the strength of the secondary granulated product.

  In addition, the heel 10b of the secondary granulator is vibrated so that the vibration force becomes smaller toward the outlet side. For this reason, the granulated material introduced into the heel 10b is secondary while weakening the rolling force. It flows towards the outlet of the granulator 10, which effectively rounds the surface.

  Secondary granulation with water replenishment strengthens the bond between particles, and in addition to this, the granulated product is rounded and the number of places where the surface tends to collapse is reduced. For this reason, a granulated product that is difficult to disintegrate by handling can be obtained.

The following are examples of the method of the present invention.
Example 1
Granulation in the sintering process of a sintered ore containing 10% of fine granulated iron that is difficult to granulate will increase the amount of quick lime added by 2.1% if the operation rate is maintained at an appropriate level. To 3% is required.

  This is because iron sand is a fine raw material having an average particle diameter of 0.2 mm, and if granulation cannot be performed firmly, the air permeability of the sintered layer is deteriorated and productivity is lowered.

Therefore, using the granulation equipment of the illustrated structure, only to iron sand blended 10% in the sintering raw material,
Granulation was performed by adding 5% quicklime to 100% iron sand.

  The granulation equipment used in this test is as follows: drum diameter of primary granulator: φ700 mm, drum length: 1700 mm, diameter of rod loaded in drum: φ60 mm, rod length: 1650 mm, number of rods loaded: 30, Excitation source: 2 weight-type vibration motors of 12 Kw (24 Kw in total), cocoon length of secondary granulator: 600 mm, total weight of rod, drum and cocoon: 5000 kg.

  The vibration acceleration applied to the drum by the vibration source is 6 G or more at the maximum, and the drum vibrates circularly by the vibration.

The kneading and granulation time by the primary granulator was 5 to 10 minutes. The granulation time in the secondary granulator is about 1-2 minutes. Moreover, the amount of water added in the primary granulator was 10 to 30%, and in the secondary granulation, the lack of moisture was digested by the primary granulation.
As a result of this experiment, the production rate was the same as when the amount of quicklime added was 3% by the conventional method.

  Next, powder raw materials other than iron sand with a quick lime addition amount of 2.1% as in the past (the composition in Example 1 is: Australian ore A16%, Australian ore B20%, Australian ore C9%, Brazilian ore A15% ), 3% scale, 10% limestone, 2.1% quicklime, 20% reclaimed mineral, 5% fine coke) and sand iron granulated material obtained in the above operation. Used as raw material.

  In this case, if the amount of cheap iron sand is increased to 10%, the conventional method required to increase the amount of quicklime to 3%, but the total amount of quicklime used is 2.39%, which is the choice of iron sand. Only the increased amount of quick lime in the granulation (0.29% = 0.1 × (5.0−2.1)) is required. As described above, when the inexpensive granulation equipment of the present invention is used, the amount of raw material having poor granulation property is increased, and an operation in which the cost is comprehensively reduced becomes possible.

The strength of the granulated product before sintering was evaluated by the following method.
A low-strength granulated product (pseudoparticle) produced by a conventional granulator such as a drum mixer is obtained by sieving the obtained granulated product and shaking the sieve softly to obtain the powder rate. As for the powder rate, for example, the ratio of the particle size of 2 mm or less, 1 mm or less, or 0.25 mm or less to the total amount is obtained.

  The inventors started by reviewing the test method itself for strength evaluation in order to investigate whether or not it has strength to withstand conveyance.

  Wet granulated products may appear to be granulated without any problems, even if they are weakly bonded to powder when dried. There is a risk of misassessment with no granulated product.

In addition, since the granulated product in a wet state clogs the sieve, the granulated product was dried and sieved. In the sieving operation, sieving was carried out while hitting the sieve with a hand or a tapping machine until no sieving (those passing through the mesh of the sieve) came out (this is called an improvement evaluation method).

  As a result, the amount of powder generated increased compared to the amount generated by the conventional method for evaluating pseudo-particles, but it was evaluated whether or not the granulation strength to withstand the conveyance in the conveying process of the sintering machine was obtained. Confirmed to be an index.

  The result of having calculated | required the occupation ratio (powder rate) of the particle | grains whose particle size is 1 mm or less about the granulated material of an Example by the evaluation method is described below. In addition, the powder rate evaluated with the conventional evaluation method about the granulated material (pseudo particle) granulated with the conventional granulator, and the powder rate which evaluated the granulated material with the said improvement evaluation method are also shown collectively.

  In the actual sintering machine, the conventional granulation method is a drum mixer system. Before introducing the method of the present invention, FIG. 5 shows the result of confirming the granulation effect using iron sand as a raw material in the laboratory (the powder ratio in FIG. 5 is a granulation apparatus using a conventional drum mixer: 45%, two-stage granulating apparatus as shown in Patent Document 1: 27%, granulating apparatus in which the center of the apparatus is vibrated in a primary / secondary integrated type: 20%, granulating apparatus for invention product: 12%).

  Compared to conventional granulation using a drum mixer, the improvement of granulation using a vibration kneading granulator is clear, but the vibration kneading granulator and the vibration kneading device type granulator with a rod removed from it When the two-stage granulation method (method of Patent Document 1) in which the two are connected is compared with the method of the present invention, it can be confirmed that the effect of the present invention is remarkable. In addition, it turned out that the apparatus of this invention is inferior in the structure where the position of the excitation source center of a vibration granulator is not unevenly distributed from the center of a drum.

  Hereinafter, based on the results of this experiment, actual machine effects obtained by replacing the drum mixer with the apparatus of the present invention will be described.

・ 35% of powder ratio evaluated by conventional evaluation method for granulated material granulated by conventional drum mixer
・ Powder rate 42% that is granulated with conventional drum mixer and evaluated by improved evaluation method
・ Powder rate of 9% that is granulated by the granulation method of the present invention and evaluated by the improvement evaluation method

  From this data, it can be seen that the strength of the granulated product using the granulation equipment of the present invention is greatly increased. Improvement of granulation has solved the deterioration of air permeability and the decrease in productivity due to the increased use of fine iron sand. The productivity comparison data is shown in Table 1.

In addition to the above effects, a secondary effect was also obtained in which the quality of the sintered ore was improved. The quality improvement effect can be evaluated by the low temperature reduced powder index. The low-temperature reduced powdering characteristics are also deteriorated by the deterioration of air permeability, but for sand iron, the chemical component titania (TiO ₂ ) contained therein is also a factor that deteriorates the quality. By selective granulation of iron sand, it is thought that the titania component was unevenly distributed in the granulated product and became difficult to participate in the sintering reaction, which led to quality improvement. Comparative data of the low-temperature reduced powdering index is also shown in Table 1.

  I in Table 1 is the productivity and low temperature reduced powdering index in the operation before adding 10% sand iron. In addition, II is the productivity and low temperature reduction powdering index by the conventional method with 10% sand iron added, and III is the productivity and low temperature reducing powdering by the method of the present invention with 10% sand iron added. Is an index.

  In this way, even if the addition amount of hardly granulated sand iron is increased, the air permeability is improved by strong granulation, and further, since the granulated material does not easily melt and diffuse, there is an adverse effect on titania sintering. Is also suppressed.

  As can be seen from the results of the above examples, according to the method of the present invention, even when the amount of added iron is increased to 10% with a slight increase in the use of quicklime, the productivity is comparable to that in the case where the amount of added iron is not increased. And low temperature reduced powdering index. Since iron sand is inexpensive, it is preferable to increase the amount used in order to reduce costs.

  As in the examples, only raw materials with poor granulation properties are taken out of the sintered raw materials, and 5% or more of quick lime is added to the raw materials 100 taken out with the granulation equipment of the present invention to efficiently increase the strength. If granulation is performed and a large number of ordinary raw materials that are relatively easy to granulate are granulated by conventional methods, the amount of quicklime added can be reduced and granulation can be maintained.

  If the two types of granules obtained in this way are mixed and used, it is possible to increase the use of fine powder and improve the sintering operation without changing the basic unit of quicklime use.

  The present invention is effective not only for improving the current operation but also for proactive use of inferior raw materials in the future. With the current blast furnace raw material sintering technology, it is difficult to increase the use of raw materials with poor granulation properties and fine powder raw materials, as compared with the present situation. If the sintering technique is used, it is possible to efficiently increase the use of these raw materials with poor granulation properties and fine powder raw materials.

-Example 2-
About 10% of quick lime was added to powdered coke, which is one of the difficult granulation raw materials in the sintered raw material, and granulation was performed using the granulation equipment used in Example 1. As a result, it was possible to obtain a granulated product having high strength that cannot be obtained by the conventional apparatus. Table 2 shows the granulation effect of the powder coke produced by this granulation equipment.

From 1) in Table 2, it can be understood how difficult it is to granulate the powder coke alone. Further, from 2), it can be seen that the improvement evaluation method considering the strength of granulation makes it difficult to increase the granulation strength with conventional granulation, and the granulated product is likely to collapse.
Furthermore, it can be seen from 3) that granulation using the granulation apparatus of the present invention provides a granulated product having high strength and hardly disintegrates.

  It is generally well known that fuel with coke and other raw materials added together is agglomerated by mixing coke and other raw materials and agglomeration of other raw materials is disturbed by the powder coke. Yes.

  Therefore, using the granulation equipment having the structure illustrated, only 10% of powdered coke is added and granulated in advance, and raw materials other than powdered coke are granulated by a conventional granulation method, and thus obtained 2 Various types of granulated materials were mixed to obtain a sintered raw material.

  The amount of quicklime added at that time was 2.1% in the conventional operation in which raw materials other than powder coke and powder coke were granulated together, but the raw material other than powder coke was excluded from powder coke that was difficult to granulate. Since the granulation property was improved, the content was reduced to 1.9%.

  The total amount of quicklime added is no different from that of conventional operations, but overall stable granulation was achieved. Table 3 shows comparison data between the conventional operation and the operation according to the method of the present invention.

Improvement in granulation of the powder coke makes combustion of the powder coke efficient, so that the burning rate is improved and the sintering temperature is improved. As a result, the production rate is improved, the binder basic unit, which is the consumption basic unit of the powder coke, is improved, and the quality such as low-temperature reduced powdering and strength is improved. At the same time, the effect of reducing NOx in the exhaust gas was also obtained by improving the combustion efficiency. In sintering, it is generally well known that the amount of NOx generated decreases as the combustion temperature rises.

  As in the examples, only raw materials with poor granulation properties are taken out of the sintered raw materials, and 5% or more of quick lime is added to the raw materials 100 taken out with the granulation equipment of the present invention to efficiently increase the strength. If most of the ordinary raw materials that are granulated and granulated relatively easily are granulated by the conventional method, the total amount of quicklime added can be reduced and the granulation can be maintained.

  Currently, globally available raw materials are rapidly deteriorating, and an increasing number of sources cannot be upgraded without strengthening ore dressing. This means that the raw materials that are not suitable for the current operation are increasing.

  In addition, from the viewpoint of resource saving and environmental improvement, it is desired to effectively use dust generated at steelworks, etc., but such generated materials are not suitable for sintering. Many. The granulation and sintering technique of the present invention makes it possible to efficiently and economically cope with future deterioration of sintered raw materials.

  The granulation facility for powder raw materials that are difficult to granulate according to the present invention is an industrial field that requires a granulated product of high-strength powder that is hard to be destroyed by handling or the like by greatly increasing the addition amount of quick lime as a binder. It can be used in all of the above, and by applying to such a field, it is possible to contribute to improvement of productivity and cost reduction.

DESCRIPTION OF SYMBOLS 1 Vibratory granulation equipment 2 Primary granulator 3 Drum 3a Raw material inlet 3b Water addition port 3c Outlet 3d Door 4 Rod 5 Excitation source 6 Base 7 Suspension device 8 Dispersion device 8a Baffle plate 9 Sprinkling device 10 Secondary granulation Device 10a Diaphragm 10b

Claims (1)

A drum (3) containing a large number of rods (4) for compaction is supported by a suspension device (7), and granulation formed in the raw material inlet (3a), water addition port (3b), and the drum A primary granulator (2) having a product outlet (3c);
A dispersing device (8) for dispersing the primary granulated product discharged from the outlet (3c) of the drum in the direction of horizontal expansion;
A secondary granulator (10) for receiving and rolling and granulating the primary granulated material supplied via the dispersing device in a number of ridges (10b) extending in the discharge direction; It has a watering device (9) for supplying moisture to the granules,
The primary granulator (2) has a vibration source (5) that vibrates the drum (3) at a vibration acceleration of 6G or more at the maximum part and circularly vibrates from the drum center (longitudinal intermediate point) on the outer periphery of the drum. The secondary granulator (10) is integrally connected to the drum (3) so as to be attached to a position biased toward the raw material charging port (3a), and is an excitation source of the primary granulator. A granulation facility configured to be vibrated by (5).

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