KR101309639B1 - A cold bonnded pellet and method for preparing thereof - Google Patents

Abstract

The present invention relates to a non-fired pellet for iron making comprising a coating layer for coating the outside of the core portion of the core portion mixed with the iron-containing raw material and the carbon-based raw material and the mixture of the iron-containing raw material and the binder raw material.

The steelmaking non-fired pellets prepared according to the present invention can maintain high strength and exhibit high reducing ability without increasing the amount of binder used.

Non-fired pellets, iron-containing materials, carbon materials, binders, compressive strength, reducing properties, core portion, coating layer

Description

Non-fired pellets, its manufacturing method and its manufacturing facilities {A COLD BONNDED PELLET AND METHOD FOR PREPARING THEREOF}

The present invention relates to a non-fired pellet for iron making and a method of manufacturing the same, and more particularly to a non-fired pellet having a double structure, a method for producing the same and its manufacturing equipment.

Non-baked pellets (CBP) refers to agglomeration of these particles with water by adding a binder to it using dust or sludge containing iron generated in steel mills.

Such non-fired pellets are used as an iron source as one of steel and steelmaking charges.

Raw materials used to prepare non-fired pellets include iron ore particles in the form of fine powders generated during the raw material processing of steel mills, various dusts generated during the steelmaking process, and various slugs generated during the steelmaking process. The method of manufacturing non-fired pellets is made of these iron ore particles, dust and slurry as main raw materials, cement as binder, additives such as quicklime, if necessary, mixed with water, and then mixed with the water. In the pelletizer, it is assembled into a size of 10 ~ 30mm and cured to produce a massive form with strength.

As described above, non-fired pellets are known to have fine powdery iron ore particles and have excellent blood repellency and an excellent effect of improving reactivity in the blast furnace.

In addition, non-fired pellets use by-products of the steelmaking process and are agglomerated at low temperatures, so that they do not need to be sintered at high temperatures, thus causing no environmental problems, low manufacturing costs, and recycling wastes. .

Typically, the physical properties required for blast furnace charge are compressive strength, iron content (T-Fe) and carbon content. In order to use non-fired pellets as blast furnace charges, it is necessary to maintain a constant compressive strength (usually 100 Kg / mm2 or more), iron content and carbon content.

In the case of preparing non-fired pellets by a conventional method, cement-based binders are used to maintain strength enough to be used in a blast furnace. However, in order to increase the strength, the amount of binder to be added must be increased. However, when the amount of binder is increased, the basicity (CaO / SiO 2) of the non-fired pellet is increased, which leads to an increase in blast furnace slag generation, which is not preferable.

In addition, in the case of non-plastic pellets containing a carbon-based component is useful for improving the reactivity in the blast furnace, there is a problem that the strength of the pellets decreases when the carbon content is increased.

The present invention is to provide a steelmaking non-fired pellet that maintains high strength and exhibits high reducing ability without increasing the amount of binder used.

In addition, the present invention is to provide a method for producing a non-fired pellet for iron making, which maintains high strength and exhibits high reducing properties without increasing the amount of binder used.

It is another object of the present invention to provide a manufacturing apparatus for steelmaking non-fired pellets that maintains high strength and exhibits high reducing properties without increasing the amount of binder used.

The manufacturing equipment of the non-fired pellet for iron making according to an embodiment of the present invention

A first iron raw material hopper for storing iron-containing raw materials, a carbon raw material hopper for storing carbonaceous materials, a first conveyor belt for transferring iron and carbon raw materials discharged from the first iron raw material hopper and the carbon raw material hopper, respectively; A first pellet granulator for assembling a first mixer for mixing the iron raw material and the carbon raw material supplied from the first conveyor belt and a first mixed raw material supplied from the first mixer to produce a core part; Wow

A second iron raw material hopper for storing iron-containing raw materials, a binder hopper for storing binder raw materials, a third conveyor belt for transferring iron raw materials and a binder discharged from the second iron raw material hopper and the binder hopper, and the third conveyor A second mixer that mixes the iron raw material and a binder supplied from a belt, and a second mixed raw material supplied from the second mixer and a core part supplied from the first pellet granulator to the outside of the core part. Second pellet granulator for coating second mixed raw material

.

The manufacturing facility for the non-fired pellet for iron making further includes a second conveyor belt for supplying the core part discharged from the primary pellet granulator to the secondary pellet granulator. In addition, the manufacturing facilities of the non-fired pellets for steelmaking according to an embodiment of the present invention is the raw material for the first iron raw material hopper and the carbon raw material hopper are sequentially arranged on the first conveyor belt in order to discharge the raw material discharged later It is arranged in a structure stacked on top.

The arrangement of the hopper is equally applicable to the second iron raw material hopper and the binder hopper.

In addition, the steelmaking non-fired pellet prepared according to an embodiment of the present invention is a mixture of the core portion and the iron-containing raw material and the binder raw material mixed by mixing the iron-containing raw material and carbon material raw material coated the outside of the core portion It includes a coating layer.

The iron-containing raw material in the non-fired pellet for iron making uses any one or two or more of fine iron ore powder, steelmaking dust, blast furnace dust, sintering furnace dust, rolled sludge and blast furnace sludge. At this time, the iron content is preferably at least 35wt% iron content.

In the steelmaking non-fired pellets, the carbonaceous raw material is a mixture of any one or two or more of coal powder or carbon-containing dust such as anthracite powder and coking coal powder.

In addition, the steelmaking non-fired pellet prepared according to an embodiment of the present invention preferably has a content of 10 to 40 wt% of the carbon component of the core portion.

In the non-baking pellets for steelmaking, the binder raw material is a mixture of one or more hydraulic binders.

In addition, the steelmaking non-fired pellet prepared according to an embodiment of the present invention preferably has a diameter ratio (R 1 / R) of the diameter (R 1) of the core portion to the diameter (R) of the non-fired pellets is 0.5 to 0.7.

And the non-baking pellets for steelmaking prepared according to an embodiment of the present invention preferably has a volume ratio (V1 / V) to the volume (V) of the core portion and the volume (V) of the non-fired pellets is 0.10 ~ 0.35.

Method for producing a non-fired steel pellets for steelmaking according to an embodiment of the present invention is a core portion manufacturing step of mixing and bulking the iron-containing raw material and carbon material raw material; And a coating layer manufacturing step of coating the outside of the prepared core part with a mixture of an iron-containing raw material and a binder raw material.

The iron-containing raw material in the method for producing non-fired pellets for steelmaking uses any one or two or more of fine iron ore powder, steelmaking dust, blast furnace dust, sintering furnace dust, rolled sludge and blast furnace sludge. And such iron-containing raw material is preferably iron content of at least 35wt% or more.

In the manufacturing method of a non-baking pellet for iron making, a carbonaceous material raw material uses what mixes any one or two or more of coal powder or carbon containing dust.

It is preferable that the content rate of the carbon component of a core part is 10-40 weight% in this manufacturing method of a non-baking pellet for iron making.

And in the manufacturing method of a non-baking pellet for iron making, the binder raw material uses what mixed one or more hydraulic binders.

In addition, in the method for manufacturing a non-fired pellet for steelmaking according to an embodiment of the present invention, the diameter ratio R 1 / R to the diameter R 1 of the core portion and the diameter R of the non-fired pellet are preferably 0.5 to 0.7. Do.

And in the manufacturing method of the non-baking pellets for steelmaking according to an embodiment of the present invention, the volume ratio (V1 / V) to the volume (V) of the core portion and the volume (V) of the non-baking pellets is preferably 0.10 ~ 0.35. .

The non-fired pellet for steelmaking prepared according to one embodiment of the present invention exhibits a technical effect of ensuring compressive strength at room temperature without increasing the amount of binder used.

In addition, the steelmaking non-fired pellets prepared according to an embodiment of the present invention also has a technical effect to improve the reactivity of the entire pellet during the steelmaking process by properly containing the carbonaceous material in the pellets.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

Figure 1 shows a facility for manufacturing non-fired pellets according to an embodiment of the present invention.

Referring to FIG. 1, a non-fired pellet manufacturing facility according to an embodiment of the present invention includes a core manufacturing facility 10 for manufacturing a core of pellets and a coating facility 50 for coating a binder on the manufactured core. do.

The core manufacturing equipment 10 includes a first iron raw material hopper 11 for storing iron-containing raw materials, a carbon raw material hopper 13 for storing carbon raw materials, a first mixer 21 for mixing the raw materials, and a mixed raw material. And a primary pellet granulator 31 for massifying them. The first conveyor belt 15 is provided in the lower end of each hopper 11, 13, and the 2nd conveyor belt 35 is also provided in the lower part of the primary pellet granulator 31. As shown in FIG.

In addition, the coating facility 50 includes a second iron raw material hopper 51 for storing iron-containing raw materials, a binder hopper 53 for storing a water-soluble binder, etc., a second mixer 61 for mixing them, and mixed these raw materials. Secondary pellet granulator 71 is coated on the assembled core pellets. The lower end of each hopper 51 and 53 of the coating installation 50 is provided with the 3rd conveyor belt 55, and the lower conveyor belt 75 is also installed in the lower end of the secondary pellet granulator 71. As shown in FIG. The pellet granulator used in one embodiment of the present invention may use any one of a disc pelletizer or a drum pelletizer, which is a motorized granulator, and individual components such as hoppers may use devices used in a steelmaking process. have.

Hereinafter, a method of manufacturing non-fired pellets by using a non-fired pellet manufacturing facility, which is an embodiment of the present invention, will be described.

First, raw material powder is put into each hopper. The raw materials available here are as follows. First, the powder used as the iron raw material may be any one of fine iron ore powder, steelmaking dust, blast furnace dust, sinter furnace dust, rolled sludge or blast furnace sludge, or a mixture thereof, and the powder preferably has iron content of at least 35 wt% or more. Do. The raw material powder used as the carbon raw material may be used alone or in combination with coal powder such as anthracite coal or coking coal or carbon-containing dust such as powder coke, coke dust, blast furnace column dust, etc. generated in the steel process. And the raw material powder used as a binder can be used any of hydraulic binders, such as a cement cement clutter, a rough cement, a super rough cement, or these mixed.

In order to manufacture the core of the pellet, fine iron ore powder or iron-containing by-products such as dust or slurry are put into the first iron raw material hopper 11, and carbon raw material such as coal powder is put into the carbon raw material hopper 13. Then, the iron raw material is discharged on the first conveyor belt 15, and the carbon raw material is discharged and stacked on the conveyor belt 15 in which the iron raw material layer is stacked. In this case, a separate conveyor belt may be installed at the lower portion of each hopper 13 and 15 to discharge raw materials using the same.

The iron raw material and the carbon raw material sequentially stacked on the first conveyor belt 15 are charged into the first mixer 21 to sufficiently mix the iron raw material and the carbon raw material. The raw materials sufficiently mixed in the first mixer 21 are charged to the subsequent primary pellet granulator 31. The mixed raw materials introduced into the first pellet granulator 31 are bulked after a predetermined time to form cores of the pellets. At this time, the primary pellet granulator 31 continues to rotate in an inclined state and can spray an appropriate amount of water. It is preferable that the diameter of the pellet core formed in the primary pellet granulator 31 is 35 mm or less.

Meanwhile, in order to coat a binder or the like on the core of the manufactured pellet, fine iron ore powder or iron-containing by-products such as dust or slurry are added to the second iron raw material hopper 51, and a water-soluble binder or the like is introduced into the binder hopper 53. do. Then, the iron raw material is discharged on the third conveyor belt 55, and the binder is discharged and stacked on the conveyor belt 55 in which the iron raw material layer is stacked. In this case, a separate conveyor belt may be installed at the lower portion of each hopper 51 or 53 to discharge the raw materials using the same.

The iron raw materials and binders sequentially stacked on the third conveyor belt 55 are charged to the second mixer 61 to sufficiently mix the iron raw materials and the binder. The raw materials sufficiently mixed in the second mixer 61 are charged to the subsequent secondary pellet granulator 71.

At this time, the secondary pellet granulator 71 is charged simultaneously or sequentially through the core 40 of the pellets manufactured in the core manufacturing facility 10 through the second conveyor belt 35.

Therefore, in the second pellet granulator 71, when the core 40 of the pellets manufactured in the core manufacturing facility 10 and the raw materials mixed in the second mixer 61 are mixed together, the pellet core 40 ) The raw material mixed with the iron raw material and the binder to form a coating layer (80). In this way, the coating layer 80 is formed outside the core 40 is a non-baking pellet to be manufactured in the present invention. At this time, the secondary pellet granulator 71 continues to rotate in an inclined state and sprays an appropriate amount of water. Then, the bulk pellets discharged from the second pellet granulator 71 are subjected to appropriate curing treatment to finally prepare non-fired pellets having a coating layer. At this time, the diameter of the prepared non-fired pellet is preferably 50 mm or less.

The non-fired pellets prepared as described above contain iron raw materials to secure iron content and at the same time the core 40 contains carbonaceous raw materials to improve the reduction of the non-fired pellets, and the coating layer 80 has a binder. It can be included to ensure the compressive strength at room temperature of the non-fired pellet.

Here, the ratio of the core portion 40 mixed with the iron raw material and the carbonaceous material and the coating layer 80 mixed with the iron raw material and the binder becomes an important factor for determining the physical properties of the manufactured non-fired pellet.

2, the diameter ratio of the core part 40 and the non-baking pellets is demonstrated. Here, when the total diameter of the non-fired pellets is set to R and the diameter of the core portion 40 is set to R1, the preferred diameter ratio is as shown in Equation 1 below.

R1 / R = 0.50 to 0. 70 -------- Equation 1

Thus, the diameter ratio (R1 / R) of the core portion 40 and the non-fired pellet is defined, if the diameter ratio is 0.5 or less, the diameter of the core portion 40 is reduced, thereby improving the reduction of the pellets and reducing the amount of binder used. When the diameter ratio is 0.70 or more, the diameter of the core portion 40 increases and the thickness of the coating layer 80 becomes thin, so that the compressive strength required at room temperature of the pellet cannot be maintained.

In addition, the volume ratio of the total volume of the non-fired pellet and the volume of the core portion 40 according to the embodiment of the present invention will be described. In order to arrange the volume ratio of the core part 40 and all pellets, the volume of all the non-baking pellets is set to V, and the volume of the core part 40 is set to V1. At this time, the preferred volume ratio is shown in Equation 2 below.

V1 / V = 0.10 ~ 0.35 ------------- Equation 2

As such, the volume ratio (V1 / V) between the core portion 40 and the non-fired pellet is defined in that, if the volume ratio is 0.10 or less, the volume of the core portion 40 decreases, thereby reducing the reduction in blood resistance, and the core portion when the volume ratio is 0.35 or more. The volume of 40 is increased and the thickness of the coating layer 80 becomes thin so that the compressive strength required at room temperature of the pellet cannot be maintained.

In addition, the content of the carbon component of the core portion 40 is preferably 10 to 40wt%. If the carbon content of the core portion 40 is less than 10wt%, the effect of reducing the reduction of the entire pellet is reduced. If the carbon content is more than 40wt%, the pellets may not be able to maintain the required strength at room temperature as well as the pellets. After completion of the reduction reaction, it is difficult to maintain the strength of the pellets due to the remaining of unreacted carbon.

As a result of manufacturing the non-fired pellets according to the embodiment of the present invention as described above, the carbonaceous material is added to the core portion 40 to improve the reactivity of the pellets and the binder is added to the coating layer 80 at the same time. The compressive strength at room temperature of the whole can be secured.

Hereinafter, embodiments of the present invention will be described in detail.

The iron-containing raw materials used in this example were used powdered iron ore of 0.1 mm or less, and finely divided coal was used as the carbonaceous material. And cement was usually used as the binder. Table 1 shows the chemical components of each raw material used in this example. In the carbon material used in Table 1, different types of coal were used to confirm the effect of each coal on the compressive strength of non-fired pellets.

Using the raw material having such a composition and pellets were prepared using a non-baking pellets production equipment according to an embodiment of the present invention.

Table 1

T.Fe (wt%) CaO
(wt%) SiO2
(wt%) Al2O3
(wt%) MgO
(wt%) C
(wt%) Iron raw materials 66.5 0.02 1.11 0.95 0.08 - Charcoal A - 1.5 8.3 3.26 0.36 75.8 Charcoal B - 0.31 5.62 2.81 0.09 63.7 Tanjae C - 1.72 8.63 3.02 0.25 85.4 bookbinder 1.1 60.6 20.6 5.3 3.5 -

Table 2 shows the raw material mixing conditions of the non-baked pellets prepared according to the examples. In addition, Table 2 shows the diameter ratio, volume ratio, and room temperature compressive strength and reduction ratio of the non-plastic pellets thus prepared. Here, the reduction rate of the non-fired pellets was measured according to JIS-RI.

[Table 2]

division Example 1 Example 2 Example 3 Example 4 Example 5 Core part (wt%) Iron raw materials 70 70 70 70 85 Carbon ash (A) - - 30 - - Carbon ash (B) 30 30 - - 15 Carbon ash (C) - - - 30 - Coating layer (wt%) Iron raw materials 90 90 90 90 90 bookbinder 10 10 10 10 10 R1 / R 0.69 0.56 0.56 0.56 0.69 Volume fraction (V1 / V) (%) 33.2 17.1 17.1 17.1 33.2 Cold compressive strength (kgf / p) 99 130 125 128 110 Reduction rate (JIS-RI) > 98 > 98 > 98 > 98 > 98

As can be seen from Table 2, in the case of non-plastic pellets prepared according to the embodiment of the present invention, all of the reducibility test results (JIS-RI) showed 99% or more. These results indicate that the sintered ore, which is a general blast furnace raw material, exhibits about 65-70% JIS-RI, and the reduction rate of the non-fired pellets prepared according to the embodiment of the present invention shows a very high value. This result is considered to be due to the influence of the carbonaceous material contained in the core portion of the non-fired pellet according to the embodiment of the present invention.

And as can be seen in Examples 1 and 2 of the present invention, as the volume ratio of the core portion 40 of the prepared non-fired pellets is small, that is, the volume fraction of the coating layer 80 increases, the room temperature compressive strength is improved. Can be.

In addition, the effect on the compressive strength of the non-fired pellet according to the change in the amount of carbonaceous material added can be seen by comparing Example 1 and Example 5. In Table 2, when the carbonaceous material (carbonaceous material B) in the core portion 40 was reduced from 30% to 15% in Example 5, the amount of non-plastic pellets produced as the amount of carbonaceous material was decreased. It can be seen that the compressive strength is increased.

Meanwhile, Table 3 shows a comparative example, in which a pellet without a core part was prepared according to a conventional method in order to compare the non-plastic pellets prepared according to the present example with the physical properties thereof. The production method used in the preparation of the pellets in the comparative example is a conventional pellet production process is applied to all of the raw materials shown in Table 1 are uniformly mixed together and then agglomerated to produce pellets.

       [Table 3]

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Example 4 Example 5 Iron raw materials 85 80 80 80 83 87 87 87 88 Charcoal A 10 10 - - - - 5 - - Charcoal B - - - 10 10 5 - - 5 Tanjae C - - 10 - - - - 5 - bookbinder 5 10 10 10 7 8 8 8 7 Cold compressive strength (kgf / p) 59 97 82 93 99 130 125 128 110

Table 3 shows the raw material blending ratio of the non-fired pellets prepared according to the comparative example and the non-fired pellets prepared according to the examples and the compressive strength of the pellets, respectively.

As shown in Table 3, the non-fired pellets prepared according to the comparative example showed that the compressive strength was lower than that of the examples even if the component ratio of the binder was higher. Therefore, when manufacturing non-fired pellets having the core portion 40 and the coating layer 80 as in the embodiment of the present invention, it can be seen that the non-fired pellets exhibited sufficient compressive strength to be used in the steelmaking process.

3 shows room temperature compressive strength according to the binder content of non-fired pellets. As can be seen in Comparative Examples 1 and 2 of FIG. 3, it can be seen that as the binder content increases, the compressive strength of the non-fired pellet increases accordingly. And in the case of Example 1 in which the binder is coated only on the coating layer of non-plastic pellets, compared to Comparative Example 1, which is a non-plastic pellet prepared by a general method without the coating layer, even if the binder content is the same Example 1 is superior to Comparative Example 1 at room temperature compression It can be seen that the strength is shown. In addition, it also shows that the room temperature compressive strength of Example 1 is superior even when compared to Comparative Example 2 in which the binder content is higher than Example 1.

Figure 4 shows the effect of the kind of carbonaceous raw material on the room temperature compressive strength of pellets prepared in a general pellet manufacturing process without a coating layer. As can be seen in Figure 4, but the effect of the compressive strength appears depending on the type of carbon material raw material it can be seen that the effect is not very large.

Figure 5 shows the compressive strength of non-plastic pellets prepared according to an embodiment of the present invention. As can be seen from FIG. 5, although different carbonaceous materials were added to the core portion 40 of the non-fired pellets, the influence of the carbonaceous materials on the normal-temperature compressive strength of the non-fired pellets is not so great. Therefore, when manufacturing the non-fired pellets by the method according to the embodiment of the present invention it can be seen that the non-fired pellets excellent in room temperature compressive strength can be produced without being greatly affected by the type of carbon material.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

1 is a conceptual diagram showing a manufacturing apparatus of non-fired pellets according to an embodiment of the present invention.

2 is a cross-sectional view showing a cross section of a non-fired pellet prepared according to an embodiment of the present invention.

Figure 3 is a graph showing the compressive strength according to the change in the cement content for the non-fired pellets prepared according to an embodiment of the present invention.

Figure 4 is a graph showing the compressive strength according to the change of the carbonaceous material for the non-fired pellets prepared according to an embodiment of the present invention.

5 is another graph showing the compressive strength according to the change of the carbonaceous material for the non-fired pellet prepared according to an embodiment of the present invention.

Claims (20)

delete delete delete delete A non-fired pellet for steelmaking comprising a coating layer for coating the outside of the core portion of the core portion mixed with the iron-containing raw material and the carbon-based raw material and agglomerated mixed with the iron-containing raw material and the binder raw material, The iron-containing raw material is a mixture of one or two or more of fine iron ore powder, steelmaking dust, blast furnace dust, sinter furnace dust, rolled sludge and blast furnace sludge, The iron-containing raw material is iron content of at least 35wt%, The carbonaceous material is a mixture of any one or two or more of coal powder or carbon-containing dust, The content rate of the carbon component of the said core part is 10-40 wt%, The binder raw material is a mixture of one or more hydraulic binders, The diameter ratio (R1 / R) with respect to the diameter (R1) of the said core part and the diameter (R) of the said non-baking pellets is a non-baking pellet for steelmaking. delete delete delete delete delete delete The method of claim 5, The volume ratio (V1 / V) of the volume (V1) of the core portion and the volume (V) of the non-fired pellets is 0.10 to 0.35. A core part manufacturing step of mixing and bulking the iron-containing raw material and the carbonaceous raw material; In the manufacturing method of the non-fired pellets for steelmaking comprising a coating layer manufacturing step of coating the outside of the core part with a mixture of the iron-containing raw material and the binder raw material, The iron-containing raw material is a mixture of one or two or more of fine iron ore powder, steelmaking dust, blast furnace dust, sinter furnace dust, rolled sludge and blast furnace sludge, The iron-containing raw material is iron content of at least 35wt%, The carbonaceous material is a mixture of any one or two or more of coal powder or carbon-containing dust, The content rate of the carbon component of the said core part is 10-40 wt%, The binder raw material is at least one hydraulic binder, A diameter ratio (R1 / R) to a diameter (R1) of the core portion and a diameter (R) of the non-fired pellets is 0.5 to 0.7. delete delete delete delete delete delete The method of claim 13, The volume ratio (V1 / V) of the volume (V1) of the core portion and the volume (V) of the non-fired pellets is 0.10 to 0.35.

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