JP2000290732A - Granulation method of raw materials for sintering with excellent flammability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for granulating a raw material for sintering having excellent flammability capable of improving flammability of pseudo particles in a sintering machine and improving productivity and yield of sinter. I will provide a. SOLUTION: In a granulation method of a raw material for sintering in which fine ore and coke are added to a drum mixer 11 and agitated to granulate into pseudo-particles, the total amount of the fine ore is 20 to 5 in advance.
0% by weight of coke was added, and the remaining coke was added to the drum mixer 11 with the total length of L as 0.5 L from the charging inlet.
Add to the range of ０．９0.98 L.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing sintered ore by adding coke to fine ore and granulating into pseudo particles.
The present invention relates to a method for granulating a raw material for sintering, which enhances the flammability of pseudo particles and improves productivity.

[0002]

2. Description of the Related Art Generally, iron ore raw materials are coke fines such as fine iron ore having a size of 8 mm or less, dust collected from dust collectors, and undersize sieves (reclaimed ore) discharged from a sintering machine. Is added, a binder such as water or quicklime is added, and pseudo particles are granulated using a drum mixer or the like, and this is charged into a sintering machine and baked at a temperature of 1100 to 1300 ° C. Is manufactured and used in blast furnaces. The quality of the sinter affects the air permeability of the blast furnace and the unloading of the blast furnace, and in some cases, the stable operation of the blast furnace and the output of the blast furnace may be hindered. Supply of ore is desired.
In addition, the sinter produced by the sintering machine depends on the quality of pseudo-particles obtained by adding fine ore and coke and granulating by adding coke. Affects the sintering state of the steel, its strength and reduced powdering ratio (RD
The properties such as I) are greatly affected, and it has been difficult to produce pseudo particles which satisfy these qualities, productivity and sintering yield. Therefore, in order to improve the quality and productivity of sinter, sintering yield, etc.
As described in Japanese Patent Publication No. 926, a water ore of 40 to 90% by weight of total use water is added to fine ore such as iron ore or rock ore and mixed with a drum mixer or the like, and the powder is firstly mixed. By producing pseudo-particles consisting only of ore, adding auxiliary materials such as coke and scale to the pseudo-particles and using a drum mixer or the like to form an adhesion layer of coke on the surface of the particles composed of iron inside, The ignitability and flammability in the sintering machine have been improved to improve the productivity of sinter. Further, as described in JP-A-62-225238,
Raw materials such as fine ore and limestone are charged into a drum mixer,
A quasi-particle is produced by adding a quasi-particle forming accelerator from a spray pipe to a moving region of the raw material in a drum mixer, and sinter ore productivity is improved by improving air permeability in a sintering machine and shortening combustion time. Improvements have been made.

[0003]

However, according to Japanese Patent Application Laid-Open No. 63-69926, an adhesion layer of coke is formed on the surface of the pseudo-particles in which the iron content is enriched. In this case, the ignitability and flammability become too good, the combustion speed rises excessively, the movement of the combustion zone from the upper layer to the lower layer becomes faster, and sufficient heat can be given to the inside with less coke. In addition, the internal sintering becomes insufficient and the formation of bonds between the particles becomes poor. As a result, the strength of the sintered ore is reduced, and the sintered ore is pulverized during the transportation process to the blast furnace or charged in the blast furnace, impairing the air permeability of the blast furnace and reducing the tapping amount. In addition, Japanese Unexamined Patent Publication
According to JP-A-225238, pseudo-particulation accelerator is added from a spray pipe into pseudo-particles in a motion region where fine ore or coke is turning into pseudo-particles while rolling in a drum mixer. Pseudo-particles are included almost uniformly, and the flammability of the pseudo-particles in the sintering machine is impaired, and there are problems such as a decrease in productivity and yield.

[0004] The present invention has been made in view of the above circumstances, and a sinter having excellent flammability capable of improving the flammability of pseudo particles in a sintering machine and improving the productivity and yield of sintered ore. It is an object of the present invention to provide a method for granulating a binding raw material.

[0005]

According to the present invention, there is provided a method for granulating a raw material for sintering having excellent flammability according to the present invention, which comprises mixing fine ore and coke with a drum mixer to granulate into pseudo particles. In the method for granulating the binding raw material, 20 to 50% by weight of the total amount of the coke and the fine ore are charged into the drum mixer in advance, and the remaining coke is charged with the total length of the drum mixer being L. 0.5L ~ 0.98 from the entrance
Add to L range. By this method, coke is contained in the inside and the surface layer of the pseudo particles, the coke exposed to the surface layer increases, the ignitability and flammability of the charged pseudo particles are increased, the burning speed of the surface layer is improved, and the inside temperature is increased. Can be burned as the temperature rises, and contradictory burning speeds can be made appropriate while improving flammability. When the position where the remaining coke is added is within a range of 0.5 L before the drum mixer, the coke inside the pseudo particles increases, or fine ore adheres to the surface of the coke itself, and the pseudo particles burn. The sinter ore strength and productivity, etc. are impaired due to a reduction in the burnability and a decrease in the burning rate. On the other hand, if it is later than 0.98 L of the drum mixer (residence time is less than 10 seconds),
The amount of coke adhering to the surface of the pseudo particles is reduced, the absolute amount of coke required for the pseudo particles is insufficient, and the combustibility and the burning speed are reduced.

The fine ore has a particle size of 500 μm.
Less than 30 to 70% by weight of fine powder. Thereby, it is possible to prevent the added coke from being buried in the pseudo-particles initially granulated or in the layer formed on the outer side thereof, thereby deteriorating the combustibility and the burning speed. If the fine powder ore having a particle size of less than 500 μm exceeds 70% by weight, the fine powder becomes too large,
The formation of pseudo particles at the beginning deteriorates, and fine ore adheres to the remaining coke to be added later, thereby impairing combustibility and the like. 50
When the amount of the fine ore having a particle size of less than 0 μm is less than 30% by weight, the mixing of coke into the pseudo particles and the adhesion of the fine ore to the coke surface are reduced, and the effect of dividing the coke addition into front and rear ends.

Further, the addition position of the remaining coke is
It can be adjusted according to the content of fine ore less than 500 μm. As a result, coke suitable for the state of the pseudo-particles initially granulated is added at an appropriate position, the coke contained in the pseudo-particles is made uniform, the coke adhering to the surface layer can be increased, and the combustibility and combustion can be increased. Speed can be made more stable.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. FIG. 1 is an overall view of an apparatus for granulating a raw material for sintering which is applied to a method for granulating a raw material for sintering having excellent flammability according to an embodiment of the present invention, and FIG. FIG. 3 is a graph comparing the volume% of fine ore and the coke for each particle size, and FIG. 3 shows the weight% of fine ore of less than 500 μm in the fine ore.
And FIG. 4 is a graph showing the relationship between the coke deposition thickness and the productivity of the sintering machine when the coke deposition thickness is set to 200 μm. As shown in FIG. 1, a sintering raw material granulating apparatus 10 used in a method for granulating a sintering raw material excellent in combustibility according to one embodiment of the present invention.
Is a drum mixer 11 that rotates in an inclined state by a driving device (not shown), a storage hopper 12 that stores fine ore such as fine iron ore, return ore, and dust in the drum mixer 11, and fine ore from the storage hopper 12. A feeder 13 for cutting, a storage hopper 14 for coke, and a feeder 15 for cutting coke from the storage hopper 14;
Belt conveyor 1 for transporting these fine ores and coke
6, a belt conveyor 18 for adding coke to the drum mixer 11 later, and a coke storage hopper 19 and a feeder 20 provided thereabove. Further, on the inlet side of the drum mixer 11, there is provided a spray pipe 21 for sprinkling water to the charged ore, and on the outlet side of the drum mixer 11, a drum mixer 1 is provided.
A sieve 22 is provided for classifying the pseudo particles obtained from Step 1. The top of the sieve 22 is conveyed as a product to a sintering machine (not shown), and the returned powder 23 to be sieved is returned to the belt conveyor 17 and supplied to the drum mixer 11 again. Here, L represents the total length of the drum mixer 11.

Next, a method of granulating a raw material for sintering having excellent flammability using the granulating apparatus 10 for raw material for sintering will be described. First, the fine ore composed of fine iron ore, turning ore, dust, and the like stored in the storage hopper 12 has a size of 6 mm or less, and particularly has a particle size of less than 500 μm (−500 μm).
30) to 70% by weight of the fine powder of m). The coke stored in the storage hopper 14 has a particle size of 6 mm or less, and each particle size is substantially averagely distributed. This fine ore and coke
The paper is cut out from the feeders 13 and 15 onto the belt conveyor 16, transferred to the belt conveyor 17 and loaded into the drum mixer 11. Finally, the total blended amount of coke to the fine ore (total added amount) is 2.5% by weight, of which 20 to 50% by weight is cut out from the storage hopper 14 here. Then, the remaining coke is added from the storage hopper 19 through the feeder 20 and the belt conveyor 18 within a range of 0.5 L to 0.98 L from the charging inlet of the drum mixer 11.

Further, as shown in FIG. 2, the distribution of each particle size (μm) of coke (△) added to the fine ore ranges from 6 mm to 12 mm.
The distribution is approximately average in the range of 5 μm. In addition, in terms of the volume% of only coke blended in the fine ore, 1.5 to 5 volume% (average of about 3.8) despite the small amount of coke added.
% By volume, which is 1.5 times the volume in terms of weight, indicating that even if the amount of coke added is small, it is sufficient to cover the surface of the pseudo particles. In the figure, □
Shows the particle size distribution when powdered mineral and coke are blended. However, this coke contains 500μ
m or more, or when the remaining coke is added in a range of less than 0.5 L from the charging side of the drum mixer 11, large particles in the coke become nuclei, and fine ore is surrounded by the core. Pseudo-particles that have adhered or coke buried inside the pseudo-particles of fine ore increase, so that pseudo-particles with enhanced flammability cannot be obtained.

[0011] Accordingly, the total amount of 20 to 5
0% by weight of coke and quick lime, limestone, etc. are added, 5 to 8% by weight of water is sprinkled from the spray pipe 21 and then stirred with the drum mixer 11 to mix fine ore and coke,
Pseudo particles containing coke inside are granulated. If the amount of coke to be added to the fine ore in advance is less than 20% by weight, the coke inside the pseudo-particles becomes insufficient, and the time for keeping the combustion speed and the combustion temperature high becomes short, and the formation and burning of bonds between the particles will be shortened. Defective results etc. occur. Further, when the amount of coke exceeds 50% by weight, the amount of coke inside the pseudo particles granulated by the drum mixer 11 increases, and the amount of coke attached to the surface decreases, so that the combustibility and the burning speed decrease. However, the yield of the sintered ore is reduced, and the quality of the sintered ore, such as the strength and the reduction pulverization rate, is reduced. Furthermore, utilizing the fact that the particle diameters (μm) of the coke are substantially averagely distributed, as shown in FIG. 3, the amount of particles less than 500 μm contained in the fine ore is 30% by weight. And drum mixer 1
By adding coke at a position of 0.5 L in the exit side with respect to the total length L of 1, an adhesion layer mainly composed of coke having a thickness of 200 μm can be formed on the surface of the pseudo particles. The adhesion layer mainly composed of coke can adjust the addition position of coke in the drum mixer 11 in accordance with the amount of particles less than 500 μm contained in the fine ore to reduce the adhesion thickness of the pseudo particles to the surface by 100%. To 250 μm, and an ideal pseudo particle having a partially exposed form can be obtained. In this adjustment, the thickness of the coke adhering to the surface of the granulated pseudo-particles was measured while changing the coke addition position under the same conditions of the fine ore and the coke, and the pallet of a sintering machine (not shown) was charged. When the layer thickness or the moving speed of the sintering machine fluctuates, the optimum productivity can be obtained within the range of 100 to 250 μm by changing the coke addition position from the above measured values and changing the coke addition position. Can be adjusted. Coke addition position
The belt conveyor 18 is advanced and retracted into the drum mixer 11 to determine the position, and the feeder 20 of the storage hopper 19 is operated to cut and convey the coke to be added to the granulated fine ore. By setting the addition amount of the remaining coke to 50 to 80% by weight of the total addition amount, an adhesion layer of 100 to 250 μm of coke is formed on the surface of the pseudo particles. If the amount of the remaining coke added to the drum mixer 11 is less than 50% by weight, the coke inside the pseudo particles increases, or the fine ore raw material adheres to the surface of the coke itself, increasing the flammability of the pseudo particles. And the burning speed decreases. Moreover, if the amount of the remaining coke added to the drum mixer 11 exceeds 80% by weight, the amount of coke adhering to the surface of the pseudo particles increases, and the burning speed becomes too high, or the coke inside the pseudo particles is reduced. This is because the amount is insufficient, which impairs the quality of the sinter. in this way,
Actively forming a coke adhesion layer on the surface of the pseudo particles,
By adjusting the adhesion thickness to 100 to 250 μm, as shown in FIG. 4, the productivity of the sintering machine (T / dm
² ) can be improved to about 29.7 to 33. The pseudo particles exiting the drum mixer 11 are classified by a sieve 22, and the sieve having a size of 10 mm or more is conveyed to a sintering machine and
The size below the sieve is supplied to the drum mixer 11 again as return powder 23.

[0012]

EXAMPLES Next, examples of a method for granulating raw materials for sintering having excellent flammability will be described. 12% by weight of serpentine or limestone powder in powder ore containing less than 500 μm of 40% by weight and 70% by weight using iron ore powder or rock ore
While mixing, while rotating a drum mixer having a diameter of 4 m and a total length of 20 m at 7 revolutions / minute, 6.5 wt% of water was externally added to make the total amount of coke added to 2.5 wt%. performing granulation by changing the addition conditions in the coke drum mixer to compare the productivity of sintered ore in the sintering machine ^{(T / d · m 2)} . As shown in Table 1, in Example 1, less than 500 μm was added to 40% by weight of fine powder ore by の of a drum mixer.
(0.5 L) at the position where the remaining 80% by weight of coke was added, and similarly, at less than 500 μm, 70% by weight of the fine ore, at a position 1/2 (0.5 L) of the drum mixer, 80% by weight of coke was added,
Productivity (T / d · m ²⁾ is 35, 31, both good results were obtained. In Example 2, 40% by weight ore less than 500 μm was added to 3/4 of the drum mixer.
(0.75 L) at the position where 50% by weight of coke was added, and similarly, at less than 500 μm, 70% by weight of fine ore, at the position of 3/4 (0.75 L) of the drum mixer, a case of adding 50 wt% of the coke productivity (T / d · m ²⁾ is 32, 32, both good results were obtained.

[0013]

[Table 1]

On the other hand, as shown in Table 2, 500
40% by weight of fine ore with less than μm and 7 with less than 500 μm
0% by weight of each of the fine ores has a total amount of 2.5% of the fine ore.
A case of adding coke is the weight percent at the entrance of all drum mixer, each of productivity (T / d · m ²⁾
However, the results were extremely bad, 25 and 20.

[0015]

[Table 2]

The embodiments of the present invention have been described above.
The present invention is not limited to the above-described embodiment, and all changes in conditions that do not depart from the gist are within the scope of the present invention. For example, as for fine ore, in addition to iron ore powder of a brand to be shipped from each locality, a dry sludge, a sintered ore powder, an underground powder, a powder containing iron, such as a pellet powder, are partially mixed and used. be able to. Further, the length of the drum mixer can be shortened or lengthened by adjusting the inclination angle to adjust the residence time or the number of revolutions.

[0017]

According to the present invention, there is provided a method for granulating raw materials for sintering having excellent flammability, wherein fine ore and coke are added to a drum mixer and agitated to granulate into pseudo particles. In the method of granulating raw materials, the total amount of 20-
50% by weight of coke was added, and the remaining coke was added to the drum mixer at a total length of 0.5 L from the charging inlet.
Since it is added in the range of 0.98 L, the flammability and burning rate of the pseudo particles charged in the sintering machine are improved, and sintering can be performed at an appropriate burning temperature, so that the productivity and yield of sintered ore can be improved.

In particular, according to the method for granulating a raw material for sintering excellent in flammability according to claim 2, since the fine ore contains 30 to 70% by weight of fine powder having a particle size of less than 500 µm, the granulated pseudo-particles To prevent coke from being buried inside and outside the
A decrease in flammability can be prevented, and the productivity of sinter can be further improved.

According to a third aspect of the present invention, there is provided a method for granulating a raw material for sintering having excellent flammability, wherein the remaining coke is added at a position of 500 μm.
m or less, the coke contained inside the pseudo-particles and the coke adhering to the surface layer can be properly adjusted, and the flammability and combustion speed are improved, and the production of sinter ore is improved. Properties and yield can be stably improved.

[Brief description of the drawings]

FIG. 1 is an overall view of an apparatus for granulating a sintering raw material applied to a method for granulating a sintering raw material excellent in combustibility according to one embodiment of the present invention.

FIG. 2 is a graph showing a comparison between volume percentages of fine particles of raw material ore and coke for each particle size applied to the granulation method.

FIG. 3 is a graph showing the relationship between the weight percentage of fine ore of less than 500 μm and the coke addition position where the coke adhesion thickness is 200 μm.

FIG. 4 is a graph showing the relationship between the coke adhesion thickness and the productivity of a sintering machine.

[Explanation of symbols]

10: Granulator for raw materials for sintering, 11: Drum mixer,
12: Storage hopper, 13: Feeder, 14: Storage hopper, 15: Feeder, 16: Belt conveyor, 17:
Belt conveyor, 18: Belt conveyor, 19: Storage hopper, 20: Feeder, 21: Spray piping, 22:
Sieve, 23: flour

Claims (3)

[Claims] 1. A method for granulating a raw material for sintering in which fine ore and coke are agitated by a drum mixer to form pseudo particles, wherein 20 to 50% by weight of the total amount of the coke and the fine ore are mixed in advance. Is charged into the drum mixer, and the remaining coke is added to the drum mixer in the range of 0.5 L to 0.98 L from the charging inlet with the total length of the drum mixer being L. Granulation method of raw material. 2. The method of claim 1, wherein the fine ore has a particle size of 500 μm.
A method for granulating a raw material for sintering which contains 30 to 70% by weight of fine powder having a particle size of less than 30 m and has excellent flammability. 3. The method for granulating a raw material for sintering excellent in flammability according to claim 1 or 2, wherein the addition position of the remaining coke is adjusted according to the content of fine ore less than 500 μm. Excellent method for granulating raw materials for sintering.