JP6426487B2 - Granulating equipment for difficult-to-granulate powder material using quicklime as binder - Google Patents

Description

  The present invention is a powder granulation that uses a large amount of raw apatite as a binder, and is a structure that makes it possible to produce a granulated material with high granulation strength, which is less likely to collapse while suppressing the generation of water vapor and dust. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a granulating apparatus, and more particularly, to a granulating apparatus employing a vibration type granulating apparatus having a simple structure.

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

  In the sintering process of iron ore which uses powder in which fine powder is mixed as blast furnace raw material, conventionally, powder is granulated.

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

  The sintered ore burns the fuel contained in the granules, and the heat from the combustion partially melts and agglomerates the granules.

  The productivity of this sintering depends on the air permeability which ensures the combustion of the fuel in the bed filled with the granulate. Conventionally, in order to promote combustion and obtain sintered ore while securing the air permeability, granulation has been performed using a drum mixer, a pan pelletizer, an Eirich mixer or the like.

  In addition, the air permeability of the granulated material packed bed is inversely proportional to the amount of fine powder in the sintering raw material, so recently, it is not granulated as compared to the conventional granulation method as described in Patent Documents 3 and 4 below. A vibrating kneader granulating apparatus has been developed that can be granulated with a small amount of fine powder that is difficult to disintegrate into powder during transportation, and a sieving device is provided at the subsequent stage of the vibrating kneader granulating apparatus A technology has also been developed to recover and reuse the raw material that has returned to powder (see Patent Document 1 below).

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

  The vibration-kneading granulating apparatus disclosed in Patent Document 3 is a primary granulating apparatus in which raw material powder is put in a container containing a large number of compaction media, and vibration acceleration of 3 G to 10 G is applied to the container to circularly vibrate the container. The secondary granulating apparatus is disposed downstream of the primary granulating apparatus, and the granulated material supplied from the primary granulating apparatus is rolled and agglomerated at a low rotational frequency using secondary granulated products not using a consolidation medium. I have to.

  In addition, Patent Document 3 discloses a secondary granulating apparatus that performs secondary granulation by dispersing and dropping flaked granulated products supplied from a primary granulating apparatus into a large number of crucibles provided in a corrugated trough. Are also disclosed together.

Japanese Patent Application No. 2007-547830 (WO2007-063603) JP, 2012-67348, A Unexamined-Japanese-Patent No. 3-166321 Japanese Patent Application Laid-Open No. 5-23567

Granulates granulated by a drum mixer, a pan pelletizer, an Eirich mixer or the like become relatively weak particles having a strength called pseudo particles. The pseudo-particles are broken down during transportation until they are loaded into the sintering machine through the transition of the conveyer from the granulator to the sintering machine through the transfer conveyor, the surge hopper and the raw material charging device, and a part is returned to powder, With regard to the minutes, the meaning of granulation is lost.

  If the mixing ratio of the powdered raw material is increased, the air permeability of the raw material packed bed of the sintering machine is lowered to cause problems in combustion, and there is a problem that the productivity of sintering is significantly reduced.

On the other hand, although the granulated material using the vibration-kneading-granulating apparatus currently disclosed by patent document 3, 4 etc. has intensity | strength increases compared with the pseudo-particle obtained by a drum mixer etc., this kind of granulation apparatus Even if it is used, it is difficult to completely eliminate the disintegration of the granulated material.

  Therefore, Patent Documents 1 and 2 enable powder-free granulation by collecting the broken 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 sieving equipment must effectively and effectively screen moisture-containing granulated matter, and the wet sieving is expensive and a special wave screen is required. It is difficult to meet that demand.

  In addition, it is known that lime is effective as a binder for the granulation reinforcement about a poorly granulated powder raw material.

  The addition of lime is generally, for example, about 2 to 3% by mass ratio with respect to quick lime (calcium oxide). If the amount of quick lime added is increased to 3% or more, it is possible to granulate difficult-to-granulate raw materials, but when a large amount of quick lime is used, the production cost becomes extremely high.

  In addition, the conventional granulating equipment generates a large amount of heat, and water vapor and dust are generated, which causes environmental problems unless a special dust collector is provided. In addition, the addition of a large amount of quick lime greatly varies the granulation strength, and the addition effect is not stable. It is already known that such a problem arises.

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

In order to make the poorly granulated powder raw material into an air-permeable granulated material that ensures strong combustion resistance and stable combustion with minimal increase in cost, a large amount of quick lime is added as a binder. Is considered the best option, but high additions of quicklime are associated with the above problems.

  In recent years, for effective use of resources, fine powders (such as concentrates which are beneficiary powders of low grade ore, iron-containing dust and sludge generated in ironworks, etc.) and non-granulation properties which have not been used conventionally There is a growing demand to use powder as a raw material without waste.

  However, no practical granulation equipment has yet been developed that can economically solve the problems caused by the large amounts of the above-mentioned addition of quick lime, and therefore, the demand for effective use of resources is sufficiently met. It is the fact that there is not.

  The present invention is a simple and economical structure granulation equipment (granulation apparatus) capable of producing a granulated product having a strength that can withstand intense handling in the transportation process while suppressing the generation of water vapor and dust due to the large addition of quick lime. The challenge is to provide

In order to solve the above-mentioned problems, in the present invention, a non-granulated powder (hereinafter referred to simply as powder) which is required by adding 3% or more of quick lime as a binder to a drum containing a large number of rods. B) adding the vibration acceleration 6 G or more at the maximum portion of the drum to make it circularly vibrate, and stirring, kneading and granulating the input material in the drum;
Dropping the primary granules formed in the drum from the outlet of the drum onto the inclined crucible of the secondary granulating device integral with the primary granulating device via the dispersing device;
Sprinkling process of adding an appropriate amount of water to the granulated material dropped onto the crucible of the secondary granulator,
The crucible of the secondary granulator is vibrated in a circle, and the circular vibration is carried out so that the vibration is damped at the tip end side of the granulated material in the downward direction of the granule, and the powder is subjected to secondary granulation. Was granulated.

  In this method, only the poorly granulated powder raw material in the sintering raw material is selected and granulated, and the granulated product obtained by this method and the granulated matter of the other powder raw material in the sintering raw material (this is The mixture can be granulated with a conventional drum mixer to form a sintering material.

The difficult-to-granulate powder material is granulated using a vibrating granulator. In the present invention, the vibratory granulating apparatus is configured as follows.
That is, a primary granulating device is supported by a suspension device with a drum containing a large number of rods for compaction, and has a raw material inlet, a water addition port, and an outlet for granulated material formed in the drum;
A dispersing device for dispersing primary granules discharged from the outlet of the drum in the direction of lateral spread;
A secondary granulating device which receives and granulates the primary granulated material supplied via the dispersing device to a large number of crucibles extending in the discharge direction, and watering which rehydrates the granulated material which performs secondary granulating Equipped with equipment,
In the primary granulating apparatus, a position where the excitation source for oscillating the circular vibration by vibrating the drum to the vibration acceleration 6 G or more at the maximum part is biased to the raw material inlet side than the drum center (longitudinal middle point) on the drum outer periphery The secondary granulating apparatus is integrally connected to the drum so as to be vibrated by a vibrating source of the primary granulating apparatus.

  By using the granulation equipment of the present invention, the generation of water vapor and dust due to the intense heat generation of quicklime is suppressed, and it becomes unnecessary to provide an environment maintenance equipment such as a special dust collection device.

  The reason is that the uniform granulation of quicklime progresses remarkably by the sliding between the rod and the drum in the drum of the primary granulator, the friction action, the grinding action and the grinding action between the rods, and the finening proceeds by the atomization. The liquefying reaction in which the quicklime is uniformly dispersed in the raw material powder and the quicklime changes to slaking occurs efficiently, uniformly, and instantaneously at each part in the drum, and for that reason, the conventional device (such as drum mixer) In comparison, local heat generation bias is reduced, and the heat is uniformly absorbed by the powder with high specific heat.

  The inventors have found through experiments that even if a large amount of quick lime is used, the heat generation and dust generation are suppressed, and a vibration kneading type granulating apparatus has been developed which can obtain the above-mentioned action and effect for primary granulation. did.

  In order to make difficult-to-granulate powder into a granulated product having a strength to withstand handling, finely divided quicklime is uniformly dispersed and uniformly deposited on the surface of the raw material powder (particles), and the particles are separated between the particles. It is important to intervene. By doing this, variations in the strength of the granulated material can be suppressed.

  In this regard, the granulation by the granulation equipment of the present invention brings out the characteristics of the vibration-kneading-type granulation apparatus to meet the requirements. Therefore, even if the addition amount of the quick lime of the binder is increased, the effect of the particle bonding is stably exhibited, and a granulated product with stable strength can be obtained.

  Furthermore, in the vibration-kneading type | mold granulation which added a large amount of quick lime, kneading | mixing advances before the disintegration reaction of quick lime in primary granulation is complete | finished. If the amount of added water is adjusted so that the maximum bonding strength can be obtained in the kneading, the water necessary for the dissolution in the secondary granulation process is consumed, resulting in a situation where the water is insufficient in the whole, ensuring high strength. It was also found by experiments that the next granulation can not be performed.

  With respect to this problem, the granulation equipment of the present invention is equipped with a water sprinkler, and can supply water to the granulated material to be subjected to secondary granulation, and the granulation strength is enhanced by the addition of the water.

  Furthermore, it was also found that granulation initially gives priority to particle agglomeration, and finally, rounding the surface is effective in reducing disintegration during the transport process.

  The granulation equipment of the present invention is a secondary structure in which the vibration source is disposed at a position biased toward the raw material inlet side with respect to the center of the drum of the primary granulation device, and the vibration source is integrated with the primary granulation device. Since the granulating apparatus is also vibrated, the vibrating force decreases in the forward direction of travel of the granulated material (the outlet side of the secondary granulating apparatus).

  As a result, the surface of the granulated material is easily rounded, and the synergetic effect of reinforcement of bonding by hydration and the suppression of disintegration by rounding the surface makes the total addition amount of quick lime more than the amount used in the conventional device. Also, it became possible to obtain high strength.

In addition, the difficult-to-granulate powder is granulated by increasing the amount of quick lime input, and the granulated product thus obtained is granulated by reducing the amount of quick lime added by the conventional granulation method such as mixer separately. If it mixes with the granulated material of the raw material of this and makes it a sintering raw material, compared with the conventional granulation method which selects poorly granulated powder and it does not granulate, the total addition amount of quick lime is reduced and it conveys Granules having a strength that can withstand the above can be obtained.

  In addition, since the primary granulating device and the secondary granulating device, which were conventionally provided separately, are integrated, simplification of the structure and reduction of the equipment cost can be realized.

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

  BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the powder granulation method and the granulation equipment of the present invention will be described below based on FIGS. 1 to 4 of the attached drawings.

  The illustrated granulation equipment 1 includes a primary granulation device 2 and a dispersing device 8 disposed downstream of the primary granulation device 2 (forward in the flow direction of the granulated material), a water sprinkler 9, and a secondary granulation device It is comprised combining 10 integrally.

  The primary granulating apparatus 2 is a vibration type granulating apparatus, and accommodates a large number of rods 4 (see FIG. 2) inside a drum 3 having a raw material inlet 3a, a water addition port 3b, and an outlet 3c of granulated material. Further, a vibration source 5 for causing the drum 3 to circularly vibrate is mounted on the outer periphery of the drum 3, and the drum 3 is supported by a suspension device 7 on a mount 6.

  3 d is a door provided at one end of the drum 3. The door 3d is provided to close the inspection port because the inspection port inside the drum 3 is provided, but the inspection port is provided as needed. Therefore, the door 3d is not essential. The drum 3 is arranged horizontally.

  The illustrated excitation source 5 is a weight type vibration motor. As this excitation source 5, one having the ability to cause the drum 3 to circularly vibrate at a vibration acceleration of 6 G (G is a gravitational acceleration) or more is used, and further, the drum center (longitudinal midpoint) of the outer periphery of the drum 3 ) Is mounted at a position deviated to the side of the raw material inlet 3a, for example, a position deviated by 0.03 × L or more from the center of a drum of a length L (primary granulator) to the side of the raw material inlet.

  The suspension 7 is provided with an air spring (air suspension), but may be a suspension comprised of a spring.

  The dispersing device 8 is disposed immediately below the outlet 3c of the drum. In the primary granulating apparatus 2, when the excitation source 5 is operated, the rod 4 inside is in the direction opposite to the rotation direction (direction A of FIG. 4) of the excitation source (weight type vibration motor) 5 (FIG. 4 Exercise in the direction B). The motion is a combination of rotation and revolution, and the powder and quicklime added to the drum 3 are crushed and kneaded by the rod 4, but the rod 4 is moved within the drum 3 because of the above-mentioned motion. It is biased as shown in FIG.

  Therefore, the powder input to the drum 3 is also biased in the same direction as the rod 4 in the process of being crushed, kneaded, and granulated, and the granulated material after primary granulation is discharged from the outlet 3c while being biased .

  It functions to uniformly disperse the biased primary granules in the direction of lateral spread (the width direction of the secondary granulating apparatus 10) and to uniformly supply it to all the crucibles 10b of the secondary granulating apparatus 10. That is, the one shown in the figure is composed of a baffle plate 8a in which the side opposite to the discharge bias direction and the flow direction front of the primary granulated material are inclined in the direction in which the position is lowered.

  The water sprinkler 9 diffuses water in the form of a mist and sprays the water downward, thereby supplying water to the granules passing through the lower side (granules that undergo secondary granulation).

  The secondary granulating apparatus 10 is provided with a large number of ridges 10b arranged in parallel in a wavelike manner on the inner surface of a concavely curved diaphragm 10a, and the diaphragm 10a has a forwardly falling direction. The upstream end is integrally connected to the drum 3 of the primary granulating apparatus 2 and held at a hollow position by the drum 3.

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

  Since it is such a structure, when the secondary granulation apparatus 10 is vibrated by the vibration source 5, the vibration force becomes smaller toward the front side in the traveling direction of the granulated material. For example, when the vibration is excited so as to have a vibration acceleration of about 6 to 8 G at the maximum, the vibration acceleration in the vicinity of the outlet of the secondary granulating apparatus 10 is reduced to about 3 to 4 G. This effectively acts to round the surface of the granules flowing in the crucible 10b.

  The secondary granulating apparatus 10 receives the replenishment of water from the water sprinkler 9 to further advance the granulation of the primary granulated product and improve the strength of the granulated product. At that time, at the same time round the surface of the granulated material. As a result, the easily collapsible portions of the surface of the granulated material (edges and bumps that trigger the collapse, etc.) are reduced, and the collapse in handling becomes even more difficult.

  The vibrating granulating apparatus 1 configured as described above operates the vibration source 5 and causes the drum 3 to circularly vibrate in a situation where the vibration acceleration at the maximum portion is 6 G or more. Then, in this state, powder for granulation purpose (for example, powder of iron ore raw material) and quicklime are simultaneously introduced into the drum 3 from the raw material inlet 3a of the primary granulating apparatus. The introduction is performed little by little continuously.

  At this time, the addition amount of quick lime is 3% (the addition amounts of quick lime, powder and water are all in the mass ratio) or more. However, since 3% or less of quick lime and capable of strong granulation are more effective according to the present device than the conventional method, the present device can be used if economy is achieved.

  Thereafter, added water is introduced from the water addition port 3b. As for the addition amount of the water, about 10 to 30% of the granulated water was appropriate in consideration of the absorption digest by quick lime and the like.

By the addition of this water, the quicklime introduced immediately reacts with the water, but since the grinding and kneading by the rod 4 in the drum 3 are made strong, almost all of the reaction heat is absorbed by the powder ( Heat absorption proceeds more effectively if the powder is an iron ore material with a high specific heat coefficient, etc.)
Ru. Therefore, although the temperature of the input powder slightly rises, the generation of water vapor and dust can be suppressed.

  This makes it possible to dispense with the installation of environmental maintenance equipment such as dust collectors.

  In addition, when the powder of quick lime added is granulated using an existing granulator such as drum mixer, massive quick lime causes local destructive reaction and is heated, so water vapor is generated at the same time. It turned out to roll up the dust around.

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

In the primary granulating apparatus 2, the quicklime introduced into the drum 3 is atomized by the function of the rod 4 moving in a circular motion, uniformly dispersed, and uniformly attached to the surface of the powder. As a result, the presence of the quicklime between the powder particles is ensured, and a granulated product in which the bonds between the particles are stable is obtained. As a result, the variation in the strength of the granulated product is reduced, and the granulated product becomes uniform in strength.

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

  The primary granules discharged from the drum 3 fall on the baffle plate 8a of the dispersing device and roll or slide on the baffle plate 8a to spread laterally, and after the deviation is leveled off, the secondary granulation device It falls on average in each weir 10b.

  The granulated material transferred to the secondary granulation device 10 is already in a condition where the water necessary for the dissolution in the secondary granulation process is already consumed and the water runs short as a whole. By supplying water, the lack of water in the granulated material to be subjected to secondary granulation is eliminated, the binding of particles is enhanced, and the strength of the secondary granulated material is increased.

  Further, the crucible 10b of the secondary granulating apparatus is vibrated so that the vibration force is smaller toward the outlet side, and therefore, the granulated material introduced into the crucible 10b has a secondary force while weakening the rolling force. It flows towards the outlet of the granulator 10, which effectively rounds the surface.

  Secondary granulation with rehydration strengthens the bonds between the particles and, in addition, the granules are rounded and the surface is less prone to disintegration. Therefore, the granulated material which collapse by handling does not occur easily occurs.

The following are examples of the method of the present invention.
-Example 1-
Granulation in the sintering process of sintered ore containing 10% of poorly granulated fine sand iron, when the production rate is maintained at an appropriate level, the amount of quick lime added is 2.1% To be increased to 3%.

  Sand iron is a fine raw material having an average particle diameter of 0.2 mm, and if the granulation can not be firmly made, the air permeability of the sintered layer is deteriorated to lower the productivity.

Therefore, using only the granulating iron of the illustrated structure, only sand iron blended in 10% of the sintering material,
Granulation was carried out by adding 5% of quick lime to 100% of sand iron.

  The granulating equipment used in this test is the drum diameter of primary granulator: φ 700 mm, drum length: 1700 mm, diameter of rod loaded in drum: φ 60 mm, rod length: 1650 mm, number of loaded rods: 30 Vibration source: Two 12 Kw weight type vibration motors (24 Kw in total), the length of the ridge of the secondary granulator: 600 mm, the total weight of the rod, the drum and the ridge: 5000 kg.

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

The kneading and granulation time by the primary granulating apparatus was 5 to 10 minutes. The granulation time in the secondary granulator is about 1 to 2 minutes. Moreover, the addition amount of water in a primary granulation apparatus was 10 to 30%, and in secondary granulation, it was digested by primary granulation and supplemented with insufficient water.
As a result of this experiment, the production rate was the same as in the conventional method where the amount of quick lime added was 3%.

  Next, powder raw materials other than sand iron with the addition amount of quick lime set to 2.1% as in the conventional case (the composition in Example 1 is 16% of ore A in Australia, 20% of ore B in Australia, 9% of ore C in Australia, 15% of Brazil ore , Granule of 3% scale, 10% limestone, 2.1% quick lime, 20% return ore, 5% coke breeze) and the iron ore granulate obtained in the above operation are mixed and sintered Used as a raw material.

  In this case, when the amount of inexpensive sand iron used was increased to 10%, it was necessary to increase the amount of quick lime to 3% in the conventional method, but the total amount of quick lime used is 2.39%, and sand iron is selected Only the increased amount of quick lime (0.29% = 0.1 × (5.0−2.1)) in granulation is sufficient. As described above, use of the inexpensive granulation equipment of the present invention makes it possible to increase the amount of raw material with poor granulation ability and to reduce the cost as a whole.

In addition, evaluation of the intensity | strength of the granulated material before sintering was performed with the following method.
Granules having a low strength (simulated particles) produced by a granulating apparatus such as a conventional drum mixer are obtained by sieving the obtained granulates, squeezing the sieves by soft sieving, and determining the powder rate. For the powder rate, for example, the ratio of particle sizes of 2 mm or less, 1 mm or less, and 0.25 mm or less in the total amount is determined.

  The inventors started by reviewing the test method itself for strength evaluation in order to determine whether or not it had strength to withstand transportation.

  Granulated matter in the wet state may seem to be granulated without problems even though it has weak bonding power to form a powder when it is dried. There is a risk of misassessment as no granulated material.

In addition, since the granulated matter in the wet state clogged the sieve, the granulated matter was dried and sieved. In the sieving operation, while tapping the sieve with a hand or a tapping machine, the sieve was sieved (the one passing through the mesh of the sieve) until it did not come out (this is called an improvement evaluation method).

  As a result, although the amount of powder generation increased compared to the amount generated by the conventional evaluation method of pseudo particles, it was evaluated whether the granulation strength which can endure the conveyance in the conveyance process of the sintering machine was obtained or not It confirmed that it became an index.

  About the granulated material of the Example by the evaluation method, the result of having calculated | required the occupancy rate (powder rate) of particle | grains whose particle size is 1 mm or less is described below. In addition, the powder rate which evaluated the granulated material (simulated particle) granulated with the conventional granulation apparatus by the conventional evaluation method, and the powder rate which evaluated the granulated material by the said improvement evaluation method are shown collectively.

  In the real machine sintering machine, the conventional granulation method is a drum mixer method. This is shown in FIG. 5 in the laboratory before the introduction of the present invention method, the results of granulation effect confirmation using sand iron as the raw material (The powder ratio in FIG. 5 is the granulator using the conventional drum mixer: Two-stage granulation apparatus as shown in Patent Document 1: 45%, granulation apparatus in which the center of the apparatus is vibrated by primary secondary integrated type: 20%, granulation apparatus according to the invention: 12%).

  Although the improvement of granulation using the vibration kneader granulator is clearer than the conventional granulation using the drum mixer, the vibration kneader granulator and the vibration kneader type granulator with the rod removed therefrom It can be confirmed that the effects of the present invention are remarkable when comparing the two-stage granulation method (the method of Patent Document 1) in which the two are connected with the method of the present invention. In addition, it turned out that an apparatus of this invention is inferior in an effect | action in the structure which does not make the position of the vibration source center center of a vibration granulation apparatus unevenly distribute from the center of drum.

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

・ Powder ratio 35% which evaluated granulated material granulated by conventional drum mixer by conventional evaluation method
・ 42% of powder rate which was granulated by conventional drum mixer and the granulated material was evaluated by the improvement evaluation method
· Powder rate 9% 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 granulated material using the granulation equipment of the present invention has a large increase in strength. The improvement of granulation eliminated the deterioration of air permeability and the decrease of productivity due to the increased use of fine sand iron powder. The comparative data of the productivity is shown in Table 1.

In addition to the above effects, secondary effects have also been obtained, in which the quality of the sintered ore is also improved. The quality improvement effect can be evaluated by the low temperature reduction powdering index. The low temperature reduction powdering property is also deteriorated by the deterioration of air permeability, but with sand iron, the chemical component titania (TiO ₂ ) contained in it also causes deterioration of the quality. It is considered that the selective granulation of sand iron led to the quality improvement that the titania component was unevenly distributed in the granulated product and less likely to be involved in the sintering reaction. Comparative data of the low temperature reduction powdering index are shown in Table 1 together.

  I of Table 1 is productivity and low temperature reduction powdering index in the operation before 10% of sand iron addition. Also, II is the productivity and low temperature reduction powder index in the conventional operation with 10% addition of sand iron, and III is the productivity and low temperature reduction powder in the operation according to the method of this invention with 10% addition of sand iron It is an index.

  As described above, even if the addition amount of poorly granulated sand iron is increased, the air permeability is improved by the strong granulation, and furthermore, the granulated material is not easily melted and diffused, which adversely affects the sintering by the titania. Is also suppressed.

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

  As in the example, only the raw material having poor granulation ability is taken out from the sintering raw material, and 5% or more of quick lime is added to the raw material 100 taken out by the granulation equipment of the present invention to efficiently obtain high strength. If granulation is carried out and a large number of ordinary raw materials which are relatively easy to be granulated are granulated by the conventional method, the addition amount of quick lime can be reduced to maintain granulation.

  By mixing and using the two types of granulated products obtained in this manner, it is possible to improve the use of fine powder and to improve the sintering operation without changing the basic unit of quick lime used as a whole.

  This invention exerts an effect not only on the current operation improvement but also on the active use of inferior raw materials in the future. With the current sintering technology for blast furnace raw materials, it is difficult to increase the use of raw materials with poor granulation ability and fine powder raw materials more than the present condition because there is a decline in productivity, quality, etc. By using the sintering technology, it is possible to increase the efficient use of these poorly granulated raw materials and finely powdered raw materials.

Example 2
About 10% of quick lime was added to the powdered coke mentioned as one of the difficult-to-granulate raw materials in the sintering raw material, and granulation was performed in the granulation equipment used in Example 1. As a result, it was possible to obtain a granulated product having high strength which can not be obtained by the conventional device. Table 2 shows the granulation effect of powdered coke by the present granulation equipment.

From 1) in Table 2, it can be understood how hard coke breeze can be granulated alone. In addition, according to the improvement evaluation method in consideration of the strength of granulation, from 2), it is difficult to increase the granulation strength in conventional granulation, and it is understood that the granulated material is easily disintegrated.
Furthermore, it can be seen from 3) that granulation with high strength and resistance to collapse is obtained by granulation using the granulation apparatus of the present invention.

  It is generally well known that when mixed coke and other materials are mixed and granulated, it is generally known that agglomeration of the other materials is disturbed by the coke and the coke is disturbed by the powder coke and the other materials are added together. There is.

  Therefore, 10% of powdered coke alone is added with 10% of quick lime and granulated in advance using the granulating equipment having the illustrated structure, and raw materials other than powdered coke are granulated according to the conventional granulation method, thus obtained 2 Granules of various types were mixed to prepare a sintering material.

  At that time, the amount of quick lime added was 2.1% in the conventional operation in which powdered coke and raw materials other than powdered coke are granulated together, but raw materials other than powdered coke are those in which powdered coke which is hard to be granulated is excluded. Reduced to 1.9% due to the improved granulation.

  Total quick lime added amount is the same as the conventional operation, but overall, stable granulation was made. Comparative data of the conventional operation and the operation according to the method of the present invention are shown in Table 3.

The granulation improvement of powdered coke makes the combustion of powdered coke efficient, and the burning rate is improved and the sintering temperature is improved. As a result, the production rate is improved, the basic consumption unit of powdered coke is improved, and the quality such as low-temperature reduction powdering and strength is improved. At the same time, the improvement of the combustion efficiency has the effect of reducing NOx in the exhaust gas. In sintering, it is generally well known that as the combustion temperature increases, the amount of NOx production decreases.

  As in the example, only the raw material having poor granulation ability is taken out from the sintering raw material, and 5% or more of quick lime is added to the raw material 100 taken out by the granulation equipment of the present invention to efficiently obtain high strength. Granulation is carried out, and if a large number of ordinary raw materials which are relatively easy to be granulated are granulated by the conventional method, it is possible to maintain the granulation by reducing the total addition amount of quick lime.

  At present, deterioration of globally available raw material resources is rapidly progressing, and an increasing number of sources can not be upgraded without beneficiary strengthening. This means that raw materials that are not suitable for current operations are increasing.

  Also, from the viewpoint of resource saving and environmental improvement, it is desirable to use dust etc. generated at steelworks etc. effectively, but such generated products are not suitable for sintering, and it is difficult to granulate difficult-to-granulate raw materials There are many. The granulation and sintering techniques of the present invention make it possible to respond efficiently and economically to the deterioration of sintering materials in the future.

  The granulation facility of the difficult-to-granulate powder raw material of the present invention greatly increases the addition amount of quicklime which is a binder, and is an industrial field requiring high-strength powder granules which are hardly broken by handling etc. Can be used in all of the above, and application to such a field can contribute to improvement in productivity and cost reduction.

Reference Signs List 1 vibration type granulation equipment 2 primary granulation device 3 drum 3a raw material inlet 3b water addition port 3c outlet 3d door 4 rod 5 excitation source 6 frame 7 suspension device 8 dispersing device 8a baffle plate 9 water spraying device 10 secondary granulation Device 10a Diaphragm 10b 樋

Claims (1)

A drum (3) containing a large number of rods (4) for compaction is supported by a suspension device (7), and a raw material inlet (3a), a water addition port (3b), and granulation formed in the drum Exit of thing (3c)
A primary granulator (2) having
A dispersing device (8) for dispersing primary granules discharged from the outlet (3c) of the drum in the direction of lateral spread;
A large number of ridges (10b) extending in the discharge direction of the primary granules supplied via the dispersing device
A secondary granulating device (10) for receiving and rolling granulation, and a water sprinkling device (9) for supplying water to the granulated material to be subjected to secondary granulation,
In the primary granulating apparatus (2), the drum center (longitudinal midpoint) of the drum outer periphery of the vibration source (5) which vibrates the circular vibration of the drum (3) by the maximum vibration acceleration unit to vibrate at a vibration acceleration of 6 G or more. ) And the secondary granulating apparatus (10) is integrally connected to the drum (3), and the secondary granulating apparatus (10) is integrally attached to the material granulating port (3a). Granulating equipment configured to be vibrated by a source (5).

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