KR101328305B1 - Method for manufacturing sintered iron ore using pellet feed - Google Patents

Abstract

Sintered ore manufacturing method, which is an aspect of the present invention is a step of mixing and primary assembly of the sintered blended raw materials including iron ore, secondary raw materials, semi-ore and fuel, iron ore: 30 to 50% by weight, pellet feed: 50 to 70% by weight, Extremely fine limestone: 5 to 20% by weight water: 10 to 14% by weight, based on the weight of the iron ore + pellet feed to make a pellet feed mixture to produce a pellet feed selection granules using the iron ore as a nucleus And secondary granulating by mixing the pellet feed selection assembly with the primary assembled sintered raw material.

Description

Sintered ore manufacturing method using ultra-fine pellet ore {METHOD FOR MANUFACTURING SINTERED IRON ORE USING PELLET FEED}

The present invention relates to a method for producing sintered ore using ultrafine pellet ore.

In the conventional DWIGHT LLOYD type sintering process, iron ore, subsidiary materials (limestone, limestone, silica sand, etc.) and fuels (powdered coke, anthracite coal), etc. are put into a drum mixer to mix and water (raw material weight ratio). The sintered blended raw material (approximately 7 to 8%) is made into pseudoparticles, charged to a certain height on the sintering machine bogie, and forcedly sucked air from the lower side after surface ignition by the ignition furnace, so that the firing of the sintered blended raw material It proceeds and a sintered ore is manufactured. After the sintering is completed, the sintered ore is cooled in a cooler through a crusher of the light distribution unit, classified into a particle size (5 to 50 mm) that is easy for charging and reaction in the blast furnace, and then transferred to the blast furnace.

As an embodiment of the method, as shown in FIG. 1, after charging and mixing the blended raw materials into the dream mixer 1, granulation is performed in the rerolling drum 2, and the assembled blended raw materials for sintering are sintered ( It is charged with 3). The charged raw material is ignited in the coke as fuel while passing through the sintering furnace of the sintering machine (3), the air in the air is sucked into the sintered surface layer by the suction pressure of the exhaust fan is subjected to the sintering process. Through this process, the sintered ore in the semi-melt state is manufactured.

At this time, the function as a binder of quicklime used as a compounding material is exhibited through the following process. That is, in the case of quicklime, a hydration reaction is caused by water sprayed into the primary mixer (drum mixer). (CaO + H ₂ O → Ca (OH) ₂ ) At this time, not only is accompanied by an exothermic reaction, but also quicklime has a large volume. Swell, and the particles become atomized. These fine particles are hermetically sandwiched between the entire blended raw materials, so that these fine particles increase the packing density of the blended raw materials, and also form bridges between the particles to improve the overall assembly of the sintered blended raw materials. .

On the other hand, the depletion of high-quality iron ore resources continues, and in the process of improving the quality after the beneficiation of low-grade ores, the inevitable increase in the amount of finely divided pellet feed is expected. Pellet Feed) and the like can not be used.

The pellet feed is a raw material for producing a fired pellet, which has a small particle size (average of 100 μm or less), and when used directly as a blending raw material for sintering, there is a problem in that the air permeability in the sintered bed may be deteriorated and the sintering productivity may be sharply lowered. Typically not used directly in the sintering process.

An example of the process of manufacturing a sintered ore using the said pellet feed is shown in FIG. As shown in Figure 2, in the case of using the pellet feed as a large amount of sintered compound feed in the DL type sintering process, by using a large amount of the finely divided pellet feed, there is a problem of increasing the overall manufacturing cost by increasing the sintering time , The overall assembly effect of the sintered blended material is remarkably inferior.

In order to solve such a problem, as shown in FIG. 3, when using a pellet feed, the pellet is fed into a high-speed stirring mixer 4, and thereafter, the pellet feeder 5 is assembled to the front end of the rerolling drum 2 through an assembly process. After the sintering process was carried out in the rerolling drum (2) was mixed and assembled with the other blended ingredients and sent to the sintering machine (3). In this case, the pellet feed is generally used as a binder in an assembly process using a high speed stirring mixer and a pelletizer, but when assembling using only water, it is difficult to develop sufficient strength of the granulated product.

As such, the use of pellet feed requires a large amount of quicklime that is currently used as a binder in order to reinforce the assembly of the blended raw material, but the manufacturing cost of the quicklime is high, and the overall manufacturing cost is not only increased. When the assembly line is utilized, there are constraints in uniformly distributing the binder, and even distribution of the pellet feed is not easy, and thus it is difficult to maintain the sintering productivity at the level before the pellet feed as a whole.

Therefore, in using the pellet feed directly for sintering, it is possible to improve the assemblability of the sintered blended raw materials through selective assembly of the pellet feed alone and the mixing design for strengthening the strength of the selected granules, thereby improving the sinter breathability and sintering productivity. It needs improvement.

One aspect of the present invention is to meet the above demands, and by selectively granulating the pellet feed, even when the pellet feed is used as a sintering raw material, not only does it improve the granulation of the sintered blended raw material and the air permeability in the sintered layer, but also improves the sintering productivity. An improved sintered ore manufacturing method is provided.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

Sintered ore manufacturing method, which is an aspect of the present invention is a step of mixing and primary assembly of the sintered blended raw materials including iron ore, secondary raw materials, semi-ore and fuel, iron ore: 30 to 50% by weight, pellet feed: 50 to 70% by weight, Extremely fine limestone: 5 to 20% by weight water: 10 to 14% by weight, based on the weight of the iron ore + pellet feed to make a pellet feed mixture to produce a pellet feed selection granules using the iron ore as a nucleus And secondary granulating by mixing the pellet feed selection assembly with the primary assembled sintered raw material.

According to the present invention, in the sintered ore manufacturing method using the pellet feed, by selectively granulating and using the pellet feed, not only the strength of the sintered ore and the air permeability in the sintered layer can be improved, but also the productivity can be improved.

1 is a flowchart showing a conventional sintering process.
2 is a flowchart illustrating a sintering process in the case of further using a pellet feed in a conventional sintering operation.
3 is a flowchart showing a sintering step performed by pretreating a conventional pellet feed.
4 is a flowchart showing a sintering step performed by pre-treating the pellet feed in the present invention.
FIG. 5 is a schematic diagram of pellet feed through the process shown in FIGS. 3 and 4.

The present inventors have conducted research to ensure productivity and quality equal to or higher than the level before pellet feed when using the pellet feed due to the depletion of high-quality iron ore raw materials. In addition to improving the air permeability, it was confirmed that the productivity can be improved and led to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the sintered ore manufacturing method of one side of the present invention.

Sintered ore manufacturing method, which is an aspect of the present invention is a step of mixing and primary assembly of the sintered blended raw materials including iron ore, secondary raw materials, semi-ore and fuel, iron ore: 30 to 50% by weight, pellet feed: 50 to 70% by weight, Extremely fine limestone: 5 to 20% by weight water: 10 to 14% by weight, based on the weight of the iron ore + pellet feed to make a pellet feed mixture to produce a pellet feed selection granules using the iron ore as a nucleus And secondary granulating by mixing the pellet feed selection assembly with the primary assembled sintered raw material.

4 shows an example of the sintered ore manufacturing method of the present invention. As shown in Figure 4, in the present invention, iron ore: 30 to 50% by weight, pellet feed: 50 to 70% by weight, ultra fine limestone: 5 to 20% by weight, based on the weight of the iron ore + pellet feed, water: 10 ~ 14% by weight of the mixture by using a mixer such as a high speed stirring mixer (4), and then pelletizing the pelletized feed selection granules in the pelletizer (5) using the iron ore of the mixture as a nucleus, the primary granulation The selective assembly is added to the sintered blended raw material and then granulated in a rerolling drum.

In the process of producing the selective feed of the pellet feed, it is preferable to mix and design the pellet feed 30 to 50% by weight, 50 to 70% by weight of the iron ore. As the content of the iron ore increases, the drop strength of the selective assembly increases in proportion to the content thereof. However, when the content is less than 50% by weight, it is difficult to secure sufficient drop strength, and when the content exceeds 70% by weight, the drop strength improvement degree is not large, so the content of the iron ore is preferably limited to 50 to 70% by weight. Do.

When the weight of the pellet feed is less than 30% by weight, the increase in strength of the granulated material is not large, and when the weight of the pellet feed exceeds 50% by weight, it is difficult to secure desired strength in the present invention.

The iron ore preferably has a particle size of 4 mm or less. If the particle size of the ferrite ore exceeds 4mm, the absolute amount of spectroscopy itself that may act as nuclear particles (Seed) during the selective assembly itself is small, and in some cases, fine particles are assembled to weaken strength. Therefore, it is preferable to use a powdered iron ore having a particle size of 4 mm or less.

The ultra fine limestone is introduced into the gap between the iron ore and the pellet feed to strengthen the packing density of the selective granules as a whole, thereby improving the strength of the selective granules. At this time, the amount of the ultrafine limestone used is preferably about 5 to 20% by weight based on the weight of the selected granule blended raw material (powder ore + pellet feed), and when it is less than 5% by weight, there is no effect of improving strength and 20% by weight. If exceeded, the ultrafine limestone added reacts with the pellet feed and the iron ore, resulting in more rapid melting than other blended raw materials, causing non-uniform firing in the sintered bed.

It is preferable that the average particle size of the said ultrafine limestone is 10 micrometers or less. In the present invention, the limestone used as flux in the sintered blending material may be pulverized and used. When the average particle size of the ultrafine limestone exceeds 10 μm, the packing density and the strength of the selective assembly may be reduced. Therefore, it is preferable that the average particle size of the said ultrafine limestone is 10 micrometers or less.

The content of water to be mixed in the present invention is preferably 10 to 14% by weight of the total moisture content of the selected granules.

On the other hand, in the present invention, an organic binder can be mixed in order to improve sufficient bonding strength between the particles of ultrafine limestone. Although any binder may be used for the said organic binder, it is preferable to use a high molecular polymer.

In addition, the content of the organic binder is preferably limited to 0.02 to 0.1% by weight based on the total weight of the selected granules. If it is less than 0.02% by weight it does not have a sufficient bonding force, if it exceeds 0.1% by weight there is a fear that the assembly itself is poor due to the increased viscosity of the organic binder.

In addition, in the present invention, the dispersant may be mixed so that the finely divided limestone is evenly distributed between the iron ore and the pellet feed particles and the particles. The mixing amount of the dispersant is preferably limited to 30 to 70% of the weight of the organic binder. More preferably, it is limited to 0.006 to 0.07% by weight based on the total weight of the selected granules. When the mixing amount is less than 30% by weight, there is a problem in that the ability to evenly disperse the organic binder is poor, and when the mixing amount exceeds 70% by weight, the amount of the organic binder itself is reduced, thereby weakening the overall binding force. have. At this time, the organic binder should have water solubility, and in particular, the concentration of the aqueous organic binder solution is preferably about 3 to 8%, and should be used in place of the aqueous organic binder solution as much as the amount of water normally used as the binder.

The mixed mixture as above is assembled in a pelletizer to prepare a pellet feed selective granule. At this time, the assembly method is not particularly limited, it is sufficient to carry out under the conditions used in the art.

As shown in FIG. 4, the iron ore, limestone, quartzite, serpentine, coke and quicklime are rerolled by mixing and primary granulation of the sintered blended raw material manufactured and assembled through the dream mixer (1). After mixing and secondary assembly in the drum (2) through the sintering machine (3) to produce a sintered ore.

The method of mixing and granulating the sintered blended raw material and the method of mixing and granulating the sintered blended raw material and the petret feed are not particularly limited and may be performed under conditions used in the art.

Hereinafter, the present invention will be described more specifically by way of examples. It should be noted, however, that the following examples are intended to illustrate the invention in more detail and not to limit the scope of the invention. The scope of the present invention is determined by the matters set forth in the claims and the matters reasonably inferred therefrom.

(Example)

The overall experiment was carried out using a sintering simulation apparatus that simulates the conditions of the field. When 10% of the pellet feed is used based on the case where the pellet feed is not used, the drum mixer, The sintering productivity variation was examined for the case where granulation was carried out using only the rerolling drum and when the selective granulation method in the present invention was used.

In addition, even when a large amount of pellet feed is used, when only water is used as a binder to utilize the selective granulation method of the present invention, and whether a pellet feed and a ferrite ore blend design of 4 mm or less are used and a new binder including an organic binder is used. In this case, the strength change of the selected granules was measured. At this time, the strength of the selective granules and the effect of improving the sintering productivity when the selected granules were used were confirmed.

Sintering experiments were performed when the pellet feed was not used and when the pellet feed was used at 10%, and the results are shown in Table 1. At this time, the use of 10% of the pellet feed as the iron iron ore used as a percentage of the amount was used as the remaining conditions, that is, the use of the remaining conditions, such as the amount of auxiliary raw materials, coke use, etc., the use of pellet feed 10% to reduce the sintering productivity Reviewed.

Pellet Feed Use 10% pellet feed Sintered Productivity (t / d / m2) 33.0 29.0

As shown in Table 1, it can be seen that the sintering productivity is reduced by 4 t / d / m ² when the pellet feed 10% is directly used without any treatment for sintering compared to the standard condition (no pellet feed use).

This is because the particle size of the pellet feed is generally thinner than 100 μm, and thus, sufficient assembly effect did not appear when assembling through a drum mixer and a rerolling drum, which are common assembly equipment.

Table 2 shows the results of the sintering experiment after the 100% selective granulation of pellet feed only by utilizing the selective granulation method of FIG. 3 in the present invention based on the above results.

Standard condition 100% pellet feed Pellet feed 10% optional after assembly use Sintered Productivity (t / d / m2) 33.0 29.0 29.5

As shown in Table 2, it can be seen that even when selective granulation is performed on only 100% of the pellet feed, it does not show a very good result compared with the case where the pellet feed is used without being selectively assembled.

This is because, as shown in Table 3, when the selective granulation is performed using only the pellet feed as a 100% blending raw material, it can be seen that the strength of the selective granulated product was not secured.

The drop strength used here represents a ratio of 4 mm or more after 300 g of samples having a particle size range of 4 to 5.3 mm in the selected granules 5 times at 2 m height.

Sinter Feed Pellet Feed 100% Assembly drop strength optional (%) 70 10

As shown in Table 3, the reason why the strength of the selective granules was not secured during the selective assembly of only 100% of the pellet feed is that there is no material that can act as nuclear particles in the selective granules as shown in FIG. It is judged that it is impossible to secure the strength of the selective granules as a whole due to the large voids of the selective granules and the lack of the finely divided particles which can strongly form the deposit layer.

Therefore, it is necessary to increase the strength of the selected granules when using a large amount in the pellet feed sintering process, in order to solve this problem, in the present invention, in the selective granulation when using a large amount of pellet feed as in the method of FIG. The mixing and use of iron ore and pellet feed were examined, and the strength of the selected granules according to the use ratio of iron ore and pellet feed was selected in order to select the optimum mixing condition of the pellet feed and ore. .

Pellet feed ratio 100 90 80 70 60 50 40 30 Min iron ore rain 0 10 20 30 40 50 60 70 Assembly drop strength optional (%) 10 18 28 39 48 53 57 60

As shown in Table 4, the drop strength of the selected granules increases in proportion to the increase in the use ratio of iron ore in the pellet feed as compared with the selective granulation for the pellet feed only.

In Table 5, after pelletizing 70% of the pellet feed + 30% of the powdered iron ore, the granules were subjected to selective granulation (the binder used was water), thereby utilizing 10% of the pellet feed in the total sintered ore raw material. , Pellet feed 70% + powdered iron ore 30% conditions of granulated selective granules using 14.2% of the sintered ore blending raw material (10% pure pellet feed) was used in the state of the sintering experiments were shown.

Standard condition Pellet feed
10% use Pellet feed
10% optional assembly
After use
(Binder moisture) Pellet feed 10% optional assembly blending design (pellet feed 70 + spectrum 30) used after (binder moisture) Sintered Productivity (t / d / m2) 33.0 29.0 29.5 31.2

As shown in Table 5, compared to 29.5 t / d / m ² which is used after the selective granulation for the pellet feed only, it can be seen that the sintering productivity is improved. However, the values were still low compared to the case where no pellet feed was used.

Although the iron ore acts as a nucleus particle and improves the packing density to some extent as the use of 30% of the iron ore is compared with the pellet feed 100%, the gap between the particles is required to obtain a higher packing density value. In addition to the addition of an ultra fine material that can fill the gap, it is determined that the use of a new binder to replace the water used as a binder.

At this time, the ultra fine material used was pulverized limestone used as flux in the sintered blended material. Prior to its use, the packing density was increased through the selective granule strength test according to the limestone particle size, thereby increasing the packing density. The particle size of the limestone useful for improving the strength was found to be about 10㎛.

The experimental results are shown in Table 6 below. (However, the experimental conditions at this time were 100% pellet feed conditions, the use rate of ultra-fine limestone was 5% constant.)

Variation of Selective Granule Strength According to the Change of Average Particle Size of Ultrafine Limestone 45㎛ 35 탆 25 μm 10 탆 Assembly Strength Optional (%) 15 20 24 35

As can be seen in Table 6, the use of ultrafine limestone improves the strength of the selected granules, as shown in (b) of FIG. 5, the microanalytical limestone is introduced into the voids between the iron ore and the pellet feed. This results in a stronger packing density of the selected granules as a whole.

When ultra-fine limestone is used, it is desirable not only to help these materials to be evenly distributed between the particles, but also to have sufficient binding force between the particles, and in the present invention, organic binders (eg, , Polymer polymer) and a dispersant having a dispersing function so as to evenly disperse them.

Table 7 below shows the results of the sintering experiment according to the various uses of the petlet feed.

Standard condition Pellet feed
10% use Pellet feed
10% optional
Use after assembly
(Binder moisture) Pellet feed
10% optional
Assembly Formulation
Used after design (pellet feed70 + spectroscopy 30)
(Binder moisture) Pellet feed
10% optional
Assembly Formulation
Use after design (pellet feed 70 + spectroscopy 30 + ultrafine limestone 5%)
(Binder organic binder + dispersant) Sintered Productivity (t / d / m ² ) 33.0 29.0 29.5 31.2 33.7

As shown in Table 7, in the use of the pellet feed during the sintering process, as shown in the present invention, the combination design of the selective granules is carried out to secure the selective granule strength, and the fineness for improving the packing density of the selective granules is improved. When limestone is added and preferably dispersants and binders are used for evenly dispersing and strengthening the binding force of these injected limestones, even though a large amount of pellet feed is used in the sintering operation, It can be seen that the sintering productivity can be secured.

1. Dream Mixer
2. Rerolling Drum
3. Sintering Machine
4. High speed stirring mixer
5. Pelletizer
6. Water
7. Pellet Feed
8. Powder iron ore (2 ~ 4㎜)
9. Powder iron ore (0.5 ~ 1㎜)
10. Ultrafine Limestone

Claims (5)

Mixing and primary granulating the sintered blended raw material including iron ore, secondary raw material, semi-ore and fuel;
Iron ore: 30 to 50% by weight, pellet feed: 50 to 70% by weight, ultrafine limestone: 5 to 20% by weight of water: 10 to 14% by weight, based on the weight of the iron ore + pellet feed. Making a pellet feed selection granule using the ferrite ore as a nucleus after the preparation; And
And mixing the pellet feed selection assembly with the first assembled sintered blended material to perform the second granulation.
A method for producing a sintered ore by adding an organic binder and a dispersant to the pellet feed mixture.
delete The method of claim 1,
The organic binder is a method of producing a sintered ore, characterized in that the polymer.
The method according to claim 1 or 3,
The content of the organic binder is 0.02 ~ 0.1% by weight, the content of the dispersing agent is a manufacturing method of sintered ore, characterized in that 0.006 ~ 0.07% by weight.
The method of claim 1,
The iron ore has an average particle size of 4 mm or less, and the ultra fine limestone has an average particle size of 10 μm or less.

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