KR20140081514A - Coal briquettes and method for manufacturing the same - Google Patents

Abstract

There is provided a molten iron manufacturing apparatus including a melter-gasifier furnished with reduced iron and a reducing furnace connected to the melter-gasifier furnishing a reduced iron, the molten iron being charged into the dome of the melter- The method for producing molded coal comprises the steps of: i) providing pulverized coal, ii) mixing 1 to 5 parts by weight of a curing agent and 5 to 15 parts by weight of a binder with respect to 100 parts by weight of pulverized coal to prepare a mixture, and iii) . In the step of providing the pulverized coal, the pulverized coal includes i) a low-grade carbon which is larger than 0 and 50 wt% or less, and ii) the remaining carbonaceous material. The low grade carbon has a volatile content of 25 wt% to 40 wt% (dry basis), and has a crucible expansion index greater than 0 and less than 3.

Description

TECHNICAL FIELD [0001] The present invention relates to a blanket,

TECHNICAL FIELD The present invention relates to a briquette and a method of manufacturing the same. More particularly, the present invention relates to a briquette containing low-grade carbon and a method of manufacturing the same.

In the melt reduction steelmaking method, a melting furnace for melting iron ores and a reduced iron ore is used. When molten iron ore is melted in a melter-gasifier, molten coal is charged into the melter-gasifier as a heat source for melting iron ore. Here, the reduced iron is melted in a melter-gasifier, converted to molten iron and slag, and then discharged to the outside. The briquetted coal charged into the melter-gasifier furnishes a coal-filled bed. Oxygen is blown through the tuyere installed in the melter-gasifier, and then the coal-packed bed is combusted to generate combustion gas. The combustion gas is converted into a hot reducing gas while rising through the coal packed bed. The high-temperature reducing gas is discharged to the outside of the melter-gasifier and supplied to the reducing furnace as a reducing gas.

The briquettes can be produced using bituminous coal. While the percentage of coal in coal is very low, no coal is produced in Korea at all. Therefore, all the bituminous coal necessary for the manufacture of molten iron is imported from overseas. Since most of the bituminous coal is produced only in some countries such as Australia, Canada, and the United States, high-quality bituminous coal used for metallurgy is gradually getting depleted, causing imbalance in supply and demand, and prices are rapidly fluctuating.

And to provide a method for producing molded coal containing low-grade carbon.

The method for producing molded coal according to one embodiment of the present invention is charged into a dome portion of a melter-gasifier in a molten steel making apparatus including a melter-gasifier furnished with reduced iron and a reducing furnace connected to the melter- Rapidly heated. The method for producing molded coal comprises the steps of: i) providing pulverized coal, ii) mixing 1 to 5 parts by weight of a curing agent and 5 to 15 parts by weight of a binder with respect to 100 parts by weight of pulverized coal to prepare a mixture, and iii) . In the step of providing the pulverized coal, the pulverized coal includes i) a low-grade carbon which is larger than 0 and 50 wt% or less, and ii) the remaining carbonaceous material. The low grade carbon has a volatile content of 25 wt% to 40 wt% (dry basis), and has a crucible expansion index greater than 0 and less than 3.

In the step of providing pulverized coal, the gross calorific value of the low-grade carbon based on anhydrous amount may be 5,500 Kcal / kg to 7,000 Kcal / kg. In the step of providing the pulverized coal, it is possible to add more than 0 and not more than 20 wt% of the carbon source additive to the pulverized coal. The carbon source additive may comprise at least one carbon source selected from the group consisting of fractional coke, coke dust, graphite, activated carbon and carbon black. The amount of the first carbon contained in the carbon source additive may be greater than the amount of the second carbon contained in the carbonaceous material.

In the step of providing the pulverized coal, the amount of the low carbon may be 10 wt% to 40 wt%. More preferably, the amount of low carbon may be from 15 wt% to 30 wt%.

In the step of preparing the mixture, the hardener may be at least one material selected from the group consisting of quicklime, slaked lime, limestone, calcium carbonate, cement, bentonite, clay, silica, silicate, dolomite, phosphoric acid, sulfuric acid and oxides. In the step of preparing the mixture, the binder may be one or more substances selected from the group consisting of molasses, bithumen, asphalt, coal tar, pitch, starch, water glass, plastic, polymer resin and oil.

Since the blast furnace is manufactured using the low-grade coal, the manufacturing cost of the blast furnace can be greatly reduced. In addition, by using low-grade carbon, the area of resource utilization can be increased.

Fig. 1 is a schematic flow chart of a method of manufacturing a briquette according to an embodiment of the present invention.
FIG. 2 is a schematic view of a molten iron manufacturing apparatus using the shaped coal produced in FIG.
FIG. 3 is a schematic view of another molten iron manufacturing apparatus using the shaped coal produced in FIG. 1. FIG.

The terms first, second and third, etc. are used to describe various portions, components, regions, layers and / or sections, but are not limited thereto. These terms are only used to distinguish any moiety, element, region, layer or section from another moiety, moiety, region, layer or section. Thus, a first portion, component, region, layer or section described below may be referred to as a second portion, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified and that the presence or absence of other features, regions, integers, steps, operations, elements, and / It does not exclude addition.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

The term "hole " as used below is interpreted to include both the shape of a hole, a line, or a surface. The "hole " thus includes both a hole or a channel-like shape.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows a flow chart of a method of manufacturing a briquette according to an embodiment of the present invention. The flow chart of the method of manufacturing the briquette of Fig. 1 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the method of manufacturing the briquette can be variously modified.

As shown in Fig. 1, the method for producing molded coal comprises the steps of: i) providing pulverized coal; ii) mixing 1 to 5 parts by weight of a curing agent and 5 to 15 parts by weight of a binder with respect to 100 parts by weight of pulverized coal to prepare a mixture , And iii) molding the mixture. In addition, if necessary, the method of manufacturing the molded coal may further include other steps.

First, in step S10, pulverized coal is provided. Pulverized coal includes low carbon and the remaining carbonaceous materials. The amount of volatile matter contained in the pulverized coal is 20 wt% to 35 wt%. When the amount of volatile matter is too small, it is impossible to produce a sufficient amount of reducing gas necessary for reduction of iron ore by charging the blast furnace made of pulverized coal into the melter-gasifier. In addition, when the amount of the volatile components is too large, the briquettes charged into the melting and gasifying furnace are easily differentiated and the heat source necessary for melting the reduced iron charged into the melting and gasifying furnace can not be sufficiently secured. Therefore, the amount of volatile matter is adjusted to the above-mentioned range.

Coal can be classified in various ways. For the classification of coal, the criterion of degree of coalification can be used. Coal burning refers to a process in which the volatile matter of a plant decreases and the amount of fixed carbon increases with time, pressure, and temperature change in the ground. Coal can be classified according to the degree of coalification as follows. That is to say, the coal is classified into two types according to the degree of coalification: peat having about 60% or less of dry ash free basis, about 60 to 70% of lignite, about 70 to 75% of bituminous coal, about 75 to 85% Bituminous coal, and about 85 ~ 94% anthracite.

On the other hand, coal may be classified into coking coal and non-coking coal depending on the degree of cohesion. Cohesive bituminous coal has the characteristic that coal particles bind to each other during carbonization. When the coal is heated, the cohesion of the coal shows heat-hardening and flow phenomenon near 350 to 400 ° C., which means that the coal particles are mutually coupled and expand due to the generation of pyrolysis gas, and exhibit shrinkage due to solidification at about 450 to 500 ° C. The degree of cohesion is evaluated by the free swelling index (FSI) according to the Coal-Crucible Expansion Index (KS E ISO 501), which measures the expansion characteristics of coal by heating the coal to a final temperature of 820 ° C and 5 ° C. Coal having a crucible expansion index of 3 or more is classified as coking coal, and coal having a crucible expansion index of less than 3 is classified as non-coking coal.

Bituminous bituminous coal is mainly used for metallurgy for the production of coke. On the other hand, since the non-coking coal has no binding ability between the coal particles, the quality of the coke is deteriorated when it is used for the production of coke, so that it can not be used for metallurgy. Therefore, lignite, bituminous coal, and bituminous coal, which are non-coking coal and have high volatile content, have been mainly used for power generation. On the other hand, anthracite coal, which is non-coking coal and has high fixed carbon and calorific value, was mainly used for pulverized coal injection (PCI).

Low-grade carbon refers to a low-cost carbon having a high volatile content as a non-coking coal having a crucible expansion index (FSI) of less than 3. Low-grade coal has mainly been pulverized into pulverized coal and used for power generation. In one embodiment of the present invention, low-cost low-grade carbon which is not used as metallurgical coal is used.

The briquettes charged in the melter-gasifier are rapidly heated at a rate of 30 ° C / min or more in direct contact with the high-temperature gas stream at about 1000 ° C in the dome located at the top of the melter-gasifier. As the heating rate increases, the softening zone rises to high temperature and the fluidity increases rapidly. At an extremely low heating rate of 3 DEG C / min, non-coking coal which is not melted is also melted at a rapid heating rate. When the viscosity changes with temperature of coal and the tar particles are large and the heating rate is high, the flow rate changes according to the release of tar, and cross - linking easily occurs at a high oxygen rate and at a low heating rate. As a result, the fluidity of the coal is increased by rapid heating. Therefore, even if melting is not easy, softening and melting are caused by rapid heating.

Since coke for metallurgy is produced by heating at a low rate of 3 ° C / min, high quality coke can be produced only if the fluidity of coal itself is high. Therefore, when low-cost low-grade carbon having low cohesion and fluidity is used, the quality of the coke is deteriorated. In contrast, the briquettes are rapidly heated at a rate of 30 占 폚 / min or more in direct contact with the hot gas stream at about 1000 占 폚 in the dome of the melter-gasifier. Therefore, it is possible to produce a molded coal using low-priced low-grade carbon which could not be used in the production of metallurgical coke. For example, a power generation molten carbon can be used as a low-grade carbon.

The pulverized coal that forms the blast furnace charged into the melter-gasifier furnace determines the behavior of the melter-gasifier. Therefore, only pulverized coal of limited characteristics can be used for the melter-gasifier. Here, the pulverized coal must satisfy various conditions in terms of cold strength, hot strength, high temperature differentiation rate, amount of recycled and amount of fixed carbon. On the other hand, quality control coal having a high average reflectance can be mixed with pulverized coal to produce coal of good quality, but there is a problem in that the cost of producing the coal is increased.

The amount of low carbon may be greater than 0 and less than 50 wt%. If the amount of the low-grade coal is too large, the quality of the molded coal to be produced deteriorates, so that the molded coal is well differentiated at a high temperature and the strength of the molded coal tends to be lowered so that the operation of the melting gasification furnace may become unstable. Therefore, the amount of low-grade carbon is adjusted to the above-mentioned range. Preferably, the amount of low-grade carbon may be from 10 wt% to 40 wt%. More preferably, the amount of the low-grade carbon may be 15 wt% to 30 wt%.

The high calorific value of low-grade carbon based on anhydrous amount may be 5,500 Kcal / kg to 7,000 Kcal / kg. The calorific value represents the amount of heat released by the coal of a unit mass during the complete combustion. The calorific value is measured by the KS E3707 standard and expressed as a gross calorific value on a dry basis. Among bituminous coal which is mainly used for metallurgy, hard carbon having a high point strength has a high calorific value of about 7,500 Kcal / kg, and a fine carbon black has a calorific value of 7,000 Kcal / kg to 7,500 Kcal / kg. The coal for metallurgy has a high calorific value of 7,000 kcal / kg or more, but the low grade carbon has 25 wt% to 40 wt% of volatile matter (dry basis), a crucible expansion index larger than 0 and less than 3 and a calorific value of 5,500 Kcal / kg to 7,000 Kcal / kg. < / RTI >

When the volatile content of the low-grade carbon is too high, volatile components contained in the blast furnace are rapidly released when the blast furnace is introduced into the melter-gasifier, and the blast furnace is differentiated. As a result, the operation of the melter-gasifier can become unstable. Among coals having a volatile content of less than 25%, coking coal having a high crucible expansion index is high-priced high-quality coal mainly used for metallurgical production of coke. On the contrary, non-coking coal having a low crucible expansion index is anthracite coal which is mainly used in the pulverized coal blowing process and is high in calorific value. Therefore, there is no coal in which the volatile content is less than 25% and the crucible expansion index is low and the calorific value is low in the low-grade carbon.

Coal having a high expansion index of crucible can be used for manufacturing coke, so it is traded at a high price. If coal having a high crucible expansion index is used for power generation, the coal is expanded due to the increase in temperature in the course of the pulverized coal being blown, and the blown nozzle is clogged. Therefore, only non-coking coal having a crucible expansion index of more than 0 and less than 3 can be used for power generation or pulverized coal blowing process so that the blowing nozzle is not clogged during blowing.

When the calorific value of the low-grade carbon is too low, it is not possible to secure a sufficient amount of heat for melting the reduced iron when the briquetted coal is introduced into the melter-gasifier. In addition, a low-calorific coal having a high calorific value may be used, but a non-coking coal having a high calorific value is an anthracite mainly used in the pulverized coal blowing process and has a low volatile content. Therefore, there is no coal having a high calorific value as non-coking coal having a low volatile content (dry basis) of 25% to 40% in the low-grade carbon with a low crucible expansion index. Therefore, the calorific value of the low-grade carbon is maintained in the above-mentioned range.

On the other hand, a carbon source additive larger than 0 and 20 wt% or less can be added to the pulverized coal. Coke powder, coke dust, graphite, activated carbon, carbon black or the like can be used as the carbon source additive. Here, the amount of the first carbon contained in the carbon source additive may be larger than the amount of the second carbon contained in the carbonaceous material. Therefore, it is possible to increase the amount of fixed carbon in the blast furnace by the carbon source additive.

That is, low-grade carbon has a high volatile content and can not be used for molten iron because the content of fixed carbon is smaller than that of bituminous coal. When the briquettes containing such low-grade carbon are used in the melter-gasifier, the amount of reducing gas generated by the briquetting coal is large, but the amount of briquetting is relatively small. In this case, more of the blast furnace should be injected into the melter-gasifier in order to supply a sufficient amount of the molten metal required for the melter-gasifier. In this case, although the reducing gas is in a surplus state, the amount of coal used per ton of molten iron is increased, and therefore the cost of manufacturing molten iron is increased. Therefore, a carbon source additive having a high carbon content is partially mixed with pulverized coal to secure the amount of fixed carbon required for the blast furnace.

Next, in step S20, 1 to 5 parts by weight of a curing agent and 5 to 15 parts by weight of a binder are mixed with 100 parts by weight of pulverized coal to prepare a mixture. As the hardening agent, it is possible to use quicklime, slaked lime, limestone, calcium carbonate, cement, bentonite, clay, silica, silicate, dolomite, phosphoric acid, sulfuric acid or oxide. When the amount of the curing agent is too small, the bonding strength between the binder and the curing agent does not sufficiently take place and the strength of the molded cement can not be sufficiently secured. In addition, when the amount of the hardener is too large, ash in the blast furnace is increased, so that it can not play a sufficient role as fuel in the melting gasification furnace. Accordingly, the amount of the curing agent is adjusted to the above-mentioned range.

As the binder, molasses, bitumen, asphalt, coal tar, pitch, starch, water glass, plastic, polymer resin or oil may be used. On the other hand, when the amount of the binder is too small, the strength of the briquette can be deteriorated. In addition, when the amount of the binder is too large, problems such as adherence occur when the pulverized coal and the binder are mixed. Therefore, the amount of the binder is adjusted to the above-mentioned range.

On the other hand, the mixing order of the curing agent and the binder can be arbitrarily set. Therefore, after mixing the hardener with the pulverized coal, the binder may be mixed with the pulverizer, or the binder may be mixed with the pulverized coal, followed by mixing the hardener.

Finally, in step S30, the mixture is molded. Although not shown in FIG. 1, the mixture can be charged between twin rolls rotating in mutually opposite directions to produce molded pockets or strips. As a result, it is possible to produce briquette having excellent hot strength and cold strength.

Fig. 2 schematically shows a molten iron manufacturing apparatus 100 using the shaped coal produced in Fig. The structure of the apparatus for manufacturing molten iron 100 of FIG. 2 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the molten iron manufacturing apparatus 100 of FIG. 2 can be modified into various forms.

The molten iron manufacturing apparatus 100 of FIG. 2 includes a melter-gasifier 10 and a reduction furnace 20. Other devices may also be included if desired. In the reduction furnace 20, iron ore is charged and reduced. The iron ore to be charged into the reduction furnace 20 is preliminarily dried and then made into reduced iron through the reduction furnace 20. The reduction furnace 20 is a packed-bed reduction reactor, and a reducing gas is supplied from the melter-gasifier furnace 10 to form a packed bed therein.

Since the briquettes produced by the production method of Fig. 1 are charged into the melter-gasifier 10, a coal-filled layer is formed inside the melter-gasifier 10. A dome portion 101 is formed on the upper portion of the melter-gasifier 10. That is, a larger space is formed compared with other portions of the melter-gasifier 10, and a high-temperature reducing gas is present therein. Therefore, the briquettes charged into the dome portion 101 by the high-temperature reducing gas can be easily differentiated. However, since the blast furnace produced by the method of Fig. 1 has a high hot strength, it does not differentiate in the dome portion of the melter-gasifier 10 and falls down to the lower portion of the melter- The gas generated by the pyrolysis reaction of the briquettes moves to the lower portion of the melter-gasifier 10 and exothermically reacts with oxygen supplied through the gasification furnace 10. As a result, the briquettes can be used as a heat source for keeping the melter-gasifier 10 at a high temperature. On the other hand, since the furnace provides air permeability, a large amount of gas generated in the lower portion of the melter-gasifier 10 and the reduced iron supplied from the reducing furnace 20 can more easily and uniformly pass through the coal packed bed in the melter- .

The lump gasification furnace 60 may be filled with the lumpy carbonaceous material or the coke as needed in addition to the above-mentioned shaped coal. A tuyere (80) is installed on the outer wall of the melter-gasifier (60) to blow oxygen. Oxygen is blown into the coal packed bed to form a combustion zone. The briquettes can be burned in the combustion zone to generate reducing gas.

Fig. 3 schematically shows a molten iron manufacturing apparatus 200 using the shaped coal produced in Fig. The structure of the molten iron manufacturing apparatus 200 of FIG. 3 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the molten iron manufacturing apparatus 200 of FIG. 3 can be modified into various forms. The structure of the molten iron manufacturing apparatus 200 of FIG. 3 is similar to the structure of the molten iron manufacturing apparatus 100 of FIG. 2, and thus the same reference numerals are used for the same parts, and detailed description thereof is omitted.

3, the molten iron manufacturing apparatus 100 includes a melter-gasifier 10, a reducing furnace 22, a reduced iron compactor 40, and a compacted iron storage tank 50. Here, the compressed reduced iron storage tank 50 may be omitted.

The produced briquettes are charged into the melter-gasifier (10). Here, the briquetting gas generates a reducing gas in the melter-gasifier 10, and the generated reducing gas is supplied to the fluidized-bed reduction reactor. The minute iron ores are supplied to a plurality of reduction furnaces 22 having a fluidized bed and are made of reduced iron while flowing by the reducing gas supplied from the melter-gasifier 10 to the reduction furnaces 22. [ The reduced iron is compressed by the reduced iron compactor 40 and then stored in the compacted iron storage tank 50. The compressed reduced iron is supplied to the melter-gasifier 10 from the compressed-reduced iron storage tank 50 and melted in the melter-gasifier 10. A large amount of gas generated in the lower portion of the melter-gasifier 10 and the compressed reduced iron make the coal filler layer in the melter-gasifier 10 more easily and uniformly distributed in the melter-gasifier 10, So that a good quality molten iron can be produced.

Hereinafter, the present invention will be described in more detail with reference to experimental examples. These experimental examples are only for illustrating the present invention, and the present invention is not limited thereto.

Experimental Example

Pulverized coal having an average particle size of 3.4 mm or less was prepared. Pulverized coal was produced by mixing metallurgical coal and low - grade coal. An additional carbon source additive was added to the pulverized coal. The characteristics of the used metallurgical coal, low carbon and carbon additive are shown in Table 1 below. The volatile content of low grade D and low grade carbon E was more than 30% and the free swelling index was 1.

To 100 parts by weight of the prepared pulverized coal, 2.7 parts by weight of burnt lime as a hardening agent was mixed, and 10 parts by weight of molasses was uniformly mixed as a binder to prepare a mixture. The mixture was compressed by a roll press to produce a pillow-shaped molded charcoal having a size of 64.5 mm X 25.4 mm X 19.1 mm. The hot strength of the briquettes was measured.

Comparative Example

For comparison with the above-mentioned experimental examples, pulverized coal was produced by using a metallurgical coal and a carbon source additive without using low-grade carbon. The manufacturing process of the remaining briquettes was the same as the above-described experimental example.

Experimental Example 1

The pulverized coal was prepared by mixing 35 wt% of the metallurgical stover A, 25 wt% of the metallurgical stover B, 30 wt% of the low-grade stover E, and 10 wt% of the carbon source additive.

Experimental Example 2

The pulverized coal was prepared by mixing 35 wt% of the metallurgical stover A, 20 wt% of the metallurgical coal B, 30 wt% of the low grade stover E, and 15 wt% of the carbon source additive.

Experimental Example 3

60 wt% of the metallurgical stover A, 30 wt% of the low-stiffness stover D, and 10 wt% of the carbon source additive were mixed to produce pulverized coal.

Experimental Example 4

Pulverized coal A was prepared by mixing 40 wt% of the metallurgical stover A, 50 wt% of the low grade stover D, and 10 wt% of the carbon source additive.

Experimental Example 5

The pulverized coal was prepared by mixing 40 wt% of the metallurgical stonewall A, 30 wt% of the metallurgical stonewall B, and 30 wt% of the low stonewall D,

Experimental Example 6

20 wt% of the metallurgical stonewall A, 70 wt% of the low-grade carbon D, and 10 wt% of the carbon source additive were mixed to produce pulverized coal.

Experimental Example 7

20 wt% of the metallurgical coal C, 70 wt% of the low-grade carbon D, and 10 wt% of the carbon source additive were mixed to prepare pulverized coal.

Comparative Example 1

35wt% of the metallurgical stonewall A, 25wt% of the metallurgical stonewall B, 30wt% of the metallurgical stonewall C, and 10wt% of the carbon monoxide additive were mixed to prepare the pulverized coal.

Experiment result

The hot strength, hot strength and fixed carbon of the molded bellows produced according to Experimental Examples 1 to 7 and Comparative Example 1 were measured.

Hot Strength Measurement Experiment

The hot strength of the blast furnace was measured to determine the degree of differentiation of the blast furnace generated inside the melter gasification furnace. To this end, about 1 kg of room-temperature molded carbon was injected into a cylindrical reactor having a diameter of 280 mm under heating conditions set at 1000 ° C. and an inert atmosphere of nitrogen, and then the cylindrical reactor was rotated at a rotation speed of 2 rpm for 15 minutes. Then, a cylindrical charger was prepared by further rotating the cylindrical current reactor at a rotating speed of 20 rpm for 30 minutes. As the degree of differentiation of the blast furnace was lower, it was judged that the hot strength was superior. Therefore, the hot strength was measured at a ratio of the flakes having a particle size of 10 mm or more at an opposed ratio.

The strongest measurement experiment

In order to confirm whether the strength of the coke produced by the apparatus for measuring the hot strength of the molded can be lowered, the strength of the molded coke was evaluated using an I-type drum apparatus for measuring the hot strength of the coke for metallurgy. That is, 200 g of the formed coal bell having a particle size of 16 mm or more was put into an I-type drum for measuring the coke hot strength of 600 mm in length, and after 600 rotations at a speed of 20 revolutions per minute, the residual ratio of 10 mm or more was measured. And the impact strength were measured. The higher the relative ratio of the briquettes obtained by the hot strength measurement method and the higher the briquetting strength, the less the briquetting of the briquetting gas in the melter-gasifier and the higher the bending strength at high temperature can be secured. The above-described measurement results of the hot strength and the highest strength and the amount of the fixed carbon measured are shown in Table 2 below.

As shown in Table 2, the hot strength, hot strength, and fixed carbon of the briquettes produced according to Experimental Examples 1 to 5 were almost the same as those of the molded carbon produced in Comparative Example 1 Respectively. Therefore, even if pulverized coal was produced by mixing low - grade coal, it was possible to produce the same characteristics as the low - grade coal. However, as in Experimental Example 6 and Experimental Example 7, in the case of using a large amount of low-grade carbon to produce the molded coal, the maximum strength was lower than the maximum strength of the blast furnace produced according to Experimental Examples 1 to 5, And therefore, it was not suitable for use as a blast furnace. Therefore, it can be confirmed that the characteristics of the blast furnace are maintained while lowering the production cost of the blast furnace when a certain amount of the low grade blast is blended.

It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the following claims.

10. Melting and gasification furnace
20, 22. Reduction furnace
30. Tungus
40. Reduction iron compression unit
50. Compressed reduced iron storage tank
100, 200. Molten iron manufacturing equipment
101. Dome

Claims (8)

A melter-gasifier furnished with reduced iron, and
A reducing furnace connected to the melter-gasifier and providing the reduced iron;
Wherein the molten iron is charged into a dome of the melting and gasifying furnace and rapidly heated,
Providing pulverized coal,
Mixing 1 to 5 parts by weight of a curing agent and 5 to 15 parts by weight of a binder with respect to 100 parts by weight of the pulverized coal to prepare a mixture, and
Molding the mixture
Lt; / RTI >
In the step of providing the pulverized coal, the pulverized coal includes low-grade coal having a weight of more than 0 and 50 wt% or less and the remaining carbonaceous material, and the low-grade carbon has a volatile content of 25 wt% to 40 wt% Wherein the crucible has an expansion index of less than < RTI ID = 0.0 > 3. ≪ / RTI > The method according to claim 1,
Wherein the low-grade coal has a gross calorific value of 5,500 Kcal / kg to 7,000 Kcal / kg in the step of providing the pulverized coal. The method according to claim 1,
Wherein the step of providing the pulverized coal further comprises adding to the pulverized coal a carbon source additive greater than 0 and equal to or less than 20 wt%. The method of claim 3,
Wherein the carbon source additive comprises at least one carbon source selected from the group consisting of partial coke, coke dust, graphite, activated carbon and carbon black, and the amount of the first carbon contained in the carbon source additive is greater than the amount of the second carbon contained in the carbonaceous material A method of manufacturing many molded carbons. The method according to claim 1,
In the step of providing the pulverized coal, the amount of the low-grade coal is 10 wt% to 40 wt%. 6. The method of claim 5,
And the amount of the low-grade carbon is 15 wt% to 30 wt%. The method according to claim 1,
Wherein the curing agent is at least one selected from the group consisting of quicklime, slaked lime, limestone, calcium carbonate, cement, bentonite, clay, silica, silicate, dolomite, phosphoric acid, sulfuric acid, ≪ / RTI > The method according to claim 1,
Wherein the binder is at least one material selected from the group consisting of molasses, bitumen, asphalt, coal tar, pitch, starch, water glass, plastic, polymer resin and oil.

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