KR20230161680A - Method of iron making used coal briquette to improve slag discharge - Google Patents

Abstract

These embodiments include a seonghyeongtan manufacturing step of producing seonghyeongtan by mixing coal and a binder; A reduced iron production step of producing reduced iron by inputting powdered iron ore into a fluidized reduction reactor; And a molten iron production step of producing molten iron by inputting the produced reduced iron and coal briquettes into a melting gasification furnace, wherein the produced coal briquettes have a melting point of ash in the range of 1400 ℃ to 1550 ℃, reduced iron and A method for manufacturing molten iron using coal briquettes is provided.

Description

Method of manufacturing molten iron using coal briquettes that improves slag discharge {METHOD OF IRON MAKING USED COAL BRIQUETTE TO IMPROVE SLAG DISCHARGE}

The present invention relates to a method of manufacturing molten iron using coal briquettes that improve slag discharge. More specifically, the present invention relates to coal briquettes that can improve the discharge of slag generated inside a melt gasification furnace by adjusting the content and ratio of components in the ash. It relates to a method of manufacturing molten iron using.

The blast furnace process is a representative molten iron manufacturing process that produces molten iron worldwide. The blast furnace process consists of a high packed bed of more than 100m, and is characterized by using sintered ore as a raw material and coke as a reducing agent and fuel among the charges. Sintered ore is made by combining powdered iron ore with secondary materials and binders at high temperature to form a lump, while coke is made by combining coking coal into a lump by drying it in a coke oven. On the other hand, the melt reduction molten iron manufacturing process is a process of manufacturing molten iron by directly using iron ore in a fine state, which is difficult to use in a blast furnace, and coal with poor cohesiveness and fluidity.

FINEX, a melt reduction molten iron manufacturing process, is largely classified into melt gasification furnace, fluidized furnace, and coal briquette process. The melting furnace process is a process in which the coal briquettes produced in the coal briquette process are inputted to generate reducing gas, and the molded iron produced in the fluidized furnace process is inputted to reduce and melt the molten iron. The fluidized furnace process is a process in which powdered iron ore is supplied with reduction gas generated from a melting furnace, and the iron is reduced through fluid reduction, and then lump-shaped iron is manufactured through a molding device. The coal briquette process is a process of producing coal briquettes using only fine coal or less coal mixed with a binder and then using a molding device.

Unlike a blast furnace, a melting furnace is a process of melting reduced iron, so it has a lower packed layer than a blast furnace. However, because the indirect reduction within the furnace is not sufficient, the consumption of coal char by direct reduction and the resulting decrease in strength lowers the porosity within the furnace, thereby hindering the flow of melt, resulting in poor slag discharge. To solve this problem, the strength of the injected coal briquettes must be increased. The strength at this time refers to the size of the char, and the char is what remains after the coal briquettes are heated in the furnace and volatile components are released, which becomes the material that makes up the packed layer in the melting furnace. . When the size of the char is large, the porosity of the packed layer in the melting furnace increases, which improves the liquid permeability that facilitates the flow of the molten material, thereby facilitating slag discharge.

FINEX coal briquettes are differentiated by being carbonized in the furnace due to the dome temperature and the gas temperature rising at the bottom of the furnace due to melt gasification, so the average particle size of the char that makes up the packed layer is about 13 to 17 mm. Meanwhile, the minimum coke diameter to ensure slag flowability in Deadman, the inert area of the blast furnace, is reported to be 20 mm, and the average particle diameter of FINEX coal char is 13 to 17 mm, so in a melt gasifier where the packed layer is composed of char, it is fundamentally There is a problem in that it is difficult for slag to flow smoothly.

The technology for increasing the coal char particle size is disclosed in domestic patent 2014-018610, which involves adding anthracite or meta-anthracite with a high degree of coalization, and in domestic patent 2021-0151312, the degree of carbon crystallinity is increased in a similar way to the method for increasing the degree of coalization. A method of adding coal or petroleum coke produced through high-temperature firing was disclosed. In addition, domestic patent 2012-0155437 disclosed a technology to increase the strength of coal briquettes, that is, the size of char, by adding graphite with high carbon crystallinity.

However, there are several problems in applying the technology for increasing the size of coal charcoal. The first is an increase in manufacturing costs, and when adding anthracite, meta-anthracite, and calcination carbon sources, they must be pulverized and the calcination temperature must be increased to maximize the effect. Therefore, the process of crushing additives and the firing process are added, increasing manufacturing costs. In the case of graphite, not only is global production limited, but the price is very expensive due to the demand for anode materials for batteries, so its applicability is low. In addition, as described above, even if the technology to increase the average particle size of coal briquettes is applied, there is a limit to forming char larger than 20 mm, so the improvement effect is minimal.

The technical object of the present invention is to provide a method for manufacturing molten iron with improved smooth discharge of slag from a FINEX melt gasifier.

In addition, the technical problem to be solved by the present invention is to provide a method for manufacturing molten iron that can solve the problem of lowering char strength and lowering melting furnace operation efficiency.

A method of manufacturing molten iron according to an embodiment of the present invention includes a coal briquette manufacturing step of mixing coal and a binder to produce coal briquettes; A reduced iron production step of producing reduced iron by inputting powdered iron ore into a fluidized reduction reactor; And a molten iron production step of producing molten iron by inputting the produced reduced iron and coal briquettes into a melting gasification furnace, wherein the ash melting point of the coal constituting the manufactured coal briquettes may range from 1400°C to 1550°C. , specifically, may range from 1450°C to 1500°C.

Additionally, pulverized coal may be additionally added in the molten iron manufacturing step.

In addition, based on the total amount of Al ₂ O ₃ , SiO ₂ , CaO, and MgO in the coal ash (Ash) converted to 100, the mass ratio of CaO and Al ₂ O ₃ may be in the range of 0.1 to 0.5, and the specific It may range from 0.3 to 0.4.

Additionally, the CaO content in the coal ash (Ash) may range from 4 wt% to 12 wt%, and specifically may range from 6 wt% to 12 wt%.

The Al ₂ O ₃ content in the ash of the coal may range from 24 wt% to 40 wt%, and specifically may range from 24 wt% to 30 wt%.

Additionally, the strength of the seonghyeongtan may be in the range of 60% to 75%.

The coal briquette manufacturing step of producing coal briquettes by mixing the coal and the binder may include a drying step of adjusting the average moisture content of the coal to a range of 5 wt% to 8 wt%, and adjusting the average particle size of the coal to a range of 2 mm to 4 mm. A preprocessing step may be included.

In the step of producing seonghyeongtan, the binder may be starch made of one or more types of corn, cassava, wheat, rice, or a combination thereof.

Additionally, the coal and binder can be mixed and heated in the range of 70°C to 130°C.

The method for manufacturing molten iron according to this embodiment has the advantage of reducing the amount of slag accumulated in the melting furnace by smoothly discharging slag in the melting furnace and improving molten iron manufacturing efficiency by reducing the gas peak.

By shortening the slag separation time in the melting furnace, the melting furnace operation efficiency is improved and the amount of fuel required to manufacture molten iron can be reduced.

1 is a schematic diagram of a molten iron manufacturing system according to an embodiment of the present invention.
Figure 2 is a schematic diagram of the molten iron manufacturing process flow according to an embodiment of the present invention.
Figure 3 shows the results of an experiment on melt discharge characteristics using the coal briquettes of Example 1 and Comparative Example 1 of the present invention.
Figure 4a shows the coal ash melting point according to the CaO content in the coal ash according to an embodiment of the present invention, Figure 4b shows the coal ash melting point according to the Al ₂ O ₃ content, and Figure 4c shows CaO/Al ₂ This shows the melting point of coal ash according to the O ₃ ratio.
Figure 5a shows the strength of coal briquettes according to the CaO content in the ash of coal according to an embodiment of the present invention, Figure 5b shows the strength of coal briquettes according to the Al ₂ O ₃ content, and Figure 5c shows CaO/Al ₂ O ₃ This shows the strength of coal briquettes according to the ratio.

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

In order to clearly explain the present invention, parts that are not relevant to the description are omitted, and identical or similar components are assigned the same reference numerals throughout the specification.

In addition, throughout the specification, when a part is said to "include" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

Although not defined differently, all terms including technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted as having meanings consistent with related technical literature and currently disclosed content, and are not interpreted in ideal or very formal meanings unless defined.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

Figure 1 is a schematic diagram of a molten iron manufacturing system according to an embodiment of the present invention, and Figure 2 is a schematic diagram of a molten iron manufacturing process flow according to an embodiment of the present invention.

Referring to Figures 1 and 2, the molten pig iron manufacturing system according to an embodiment of the present invention is composed of a FINEX melting reduction molten pig iron manufacturing apparatus, and the powdered iron ore and auxiliary raw materials are put into the fluidized reduction furnace 100 for pre-reduction. Then, molded iron is manufactured in the molded iron manufacturing device 112 connected to the fluidized reduction furnace, and the coal briquettes manufactured in the coal briquette manufacturing device 200 are inputted into the melting gasifier 300 to produce molten iron.

The fluidized reduction furnace 200 is a device that produces reduced iron by reducing powdered iron ore. Inside the reduction furnace, a dispersion plate to equalize the flow of reducing gas and a cyclone to collect scattered iron ore may be installed. A plurality of such fluidized reduction reactors may be installed, preferably three to four.

The molded iron manufacturing device 110 can receive pre-reduced reduced iron from a storage device 111 and form it in a hot state in the molded iron manufacturing device 112. The manufactured molded iron may be crushed to a certain size in the molded iron crusher 113 and then introduced into the melting gasifier 300.

The coal briquette manufacturing apparatus 200 mixes coal and a binder and molds them to produce coal briquettes, and the produced coal briquettes can be input into the melt gasification furnace 300. The coal pre-treatment device 201 may be a device that controls the particle size and moisture of coal, and may include a pre-treatment device that adjusts the average particle size of coal in the range of 2 mm to 4 mm.

Additionally, it may include a drying device that adjusts the moisture content of the coal to a range of 5wt% to 8wt%. The binder may be starch made of one or more types of corn, cassava, wheat, rice, or a combination thereof, but is not limited thereto.

Coal supplied from the coal preprocessing device 201 can be stored in the coal storage device 202 and extracted in fixed quantities. The binder supplied from the binder storage device 203 and the coal cut out in fixed quantities may be supplied to the heating device 204 and heated to a temperature range of 70°C to 130°C while being stirred by blown steam and an internal stirrer. The coal may be used as a mixture of one type or two or more types of coal.

The mixture of heated coal and binder can be supplied to the molding machine 205 to produce coal briquettes. The manufactured coal briquettes are supplied to the particle size sorter 206, and the coal briquettes of a certain size or larger are supplied to the coal briquette storage device 207. The coal briquettes stored in the coal briquette storage device may be input into the melt gasification furnace 300.

The melt gasification furnace 300 melts the input molded iron to produce molten iron, the volatile content of coal from the input coal briquettes generates reducing gas, and the remaining char forms a packed bed. The reduction gas generated at the top of the melt gasification furnace is supplied to the first fluidized reduction furnace (104). Pure oxygen and pulverized coal, an auxiliary fuel, can be blown into the tuyere, and manufactured molten iron and slag can be discharged through the tap.

The sources of FINEX slag are HCI (Hot Compacted Iron), an iron source, coke, a reducing agent and fuel, coal briquettes, and agglomerated raw materials, and may be additionally added pulverized coal. Table 1 below shows the basic unit and ratio of slag generation sources. 77.5% of the total slag is generated from gangue of HCI, an iron raw material, and 12.5% is generated from coal ash in the reducing agent and fuel field, which can be said to be the largest input source.

division Slag generation source unit (kg/t-p) ratio (%) sad
they say
that HCI 248 77.5 Seonghyeongtan 40 12.5 cokes 9 2.8 pulverized coal 13 4.1 Mass raw material (silica stone) 10 3.1 Sum 319 100

The ash component of coal, which is the raw material for producing coal briquettes, not only affects the formation of slag, but also has a significant impact on the strength of coal briquettes. In general, as the proportion of Ca, Na, and K-based oxides, which are basic components in coal ash, increases, the solution loss reaction with CO ₂ increases and the strength of coal briquettes decreases. Therefore, in order to increase the strength of coal briquettes, coal with a low base content among ash is mainly used. However, coal with a low base content not only has a low Ca-based component, but conversely, it means that the content of Al ₂ O ₃ and SiO ₂ , which are the main components of slag, is increased. When the Ca-based component is low and the Al ₂ O ₃ and SiO ₂ contents are high, the ash melting point of coal briquettes increases, which results in worsening the discharge of slag from the melting furnace.

In an embodiment of the present invention, the ash melting point of coal may range from 1400°C to 1550°C, and specifically may range from 1450°C to 1500°C. Meanwhile, the strength of coal briquettes may range from 60% to 75%.

Hereinafter, examples and comparative examples of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

Comparative Example 1

Coal briquettes having the characteristics shown in Table 2 below were prepared and tested for molten iron production. The CaO content in coal ash, which is the raw material for producing coal briquettes, is 5.6 wt%, the Al ₂ O ₃ content is 31.9 wt%, the CaO/Al ₂ O ₃ ratio is 0.18, and the strength of coal briquettes is 73%, making it suitable for high-strength coal briquettes. It has a melting point of 1,518°C.

Meanwhile, in the examples and comparative examples of the present invention, the component content in the ash (Ash) of coal, which is a raw material of coal briquettes, the strength of coal briquettes, and the ash (Ash) melting point of coal were obtained by the following methods, and Comparative Example 2 and Example described later Overlapping explanations in the examples are omitted.

The component content of the coal ash (Ash) is the ratio of the content of each component when the total sum of the four components Al ₂ O ₃ , SiO ₂ , CaO, and MgO measured through wet analysis is set to 100. will be.

The strength of coal briquettes means the mass ratio of coal briquettes with a size of 10 mm or more among the coal briquettes obtained after 600 rotations of putting the remaining char after reaction in an I-type drum under the condition of supplying a 100% CO ₂ atmosphere.

Ash melting point is calculated by using the commercial thermodynamic calculation program Factsage to determine the temperature at which complete melting occurs thermodynamically using the four components of coal ash, Al ₂ O ₃ , SiO ₂ , CaO, and MgO, as input conditions. This is the result.

Coal Ash composition (wt%) Seonghyeongtan strength (%) Ash melting point (℃) note Al ₂ O ₃ SiO ₂ CaO MgO melting temperature 31.9 59.8 5.7 2.6 73 1,518 high melting point

Table 3 below shows the slag discharge performance, number of gas peaks, and coal ratio indicating operation efficiency as a result of the molten iron production operation when the coal briquettes of Table 2 are applied to the molten iron production system shown in FIG.

Slag discharge gases Operation efficiency note Low slag amount (ton) Slag separation time (minutes) Gas Peak (time) Coal ratio (kg/t-p) 123 45 9.5 789 high melting point

As shown in Table 3, when using the coal briquettes in Table 2, the low slag amount was found to be very high at 123 tons, and the slag separation time was found to be 45 minutes. Here, the low slag amount refers to the above-mentioned slag accumulation amount, and in a physical sense, it means the amount of slag present in the melt gasification furnace. A long initial slag separation time is equivalent to a decrease in slag discharge time in a limited tapping time, which causes an increase in low slag. When the tap port is drilled, molten iron and slag come out. In most cases, molten iron comes out first and slag comes out later, and the discharged molten iron/slag is separated by density difference, and the time required for separation is called slag separation time. In addition, the time that the tap port can be open is limited, so if the initial slag discharge time is delayed, the amount of slag in the melting furnace increases. The tapping hole is made by firing the mud material, a hole is drilled there to discharge the molten material, and as it is discharged, the hole expands and closes after a certain time, which is called a limited tapping time.

If the amount of low slag increases, the possibility of molten material filling up to the tuyere and causing damage to the tuyere increases, and the gas resistance in the furnace increases, increasing the gas peak, which reduces the melting furnace operation efficiency, resulting in a high coal ratio. As the amount of slag accumulates within the limited melting furnace space, the pressure rises, and if the input layer (coal coal, coke) cannot withstand it, a gas peak occurs. The gas peak is when high-temperature gas fails to exchange heat and escapes out of the furnace, making the input layer non-uniform, resulting in a decrease in molten iron temperature and an increase in coal ratio.

Comparative Example 2

Coal briquettes having the characteristics shown in Table 4 below were prepared and tested for molten iron production. The CaO component content in the ash of coal is 3.4 wt%, the Al ₂ O ₃ component content is 33.7 wt%, the CaO/Al ₂ O ₃ ratio is 0.11, and the strength of the coal briquettes is 74%, corresponding to high-strength coal briquettes. The melting point is 1,553℃.

Coal Ash composition (%) Seonghyeongtan strength (%)
Ash melting point (℃) note Al ₂ O ₃ SiO ₂ CaO MgO melting temperature 33.5 61.1 3.6 1.8 74 1,553 high melting point

Table 5 below shows the slag discharge performance, number of gas peaks, and coal ratio indicating operation efficiency as a result of the molten iron production operation when the coal briquettes of Table 4 are applied to the molten iron production system shown in FIG.

Slag discharge gases Operation efficiency note Low slag amount (ton) Slag separation time (minutes) Gas Peak (time) Coal ratio (kg/t-p) 142 52 12.4 802 high melting point

As shown in Table 5, the results of the molten iron manufacturing operation using the coal briquettes of Table 4 with high melting point Ash characteristics resulted in a low slag amount of 142 tons and a slag separation time of 52 minutes. Compared to Comparative Example 1, the flow of molten material in the melt gasification furnace was not smooth. It turned out that it was not. In addition, the number of gas peak occurrences increased to 12.4, and the coal ratio increased to 802kg/t-p.

From this, it can be seen that in order to realize high-efficiency operation of 800 kg/t-p or less, it is desirable to adjust the ash melting point to 1,550°C or less, and it is also desirable that the CaO content is 4.0% or more.

Example 1

Coal briquettes having the characteristics shown in Table 6 below were prepared and tested for molten iron production. The CaO content in the ash of coal is 9.0 wt%, the Al ₂ O ₃ content is 29.6 wt%, the CaO/Al ₂ O ₃ ratio is 0.31, the strength of coal briquettes is 69%, and the melting point is 1,440°C. It corresponds to low melting point.

Coal Ash composition (%) Seonghyeongtan strength (%) Ash melting point (℃) note Al ₂ O ₃ SiO ₂ CaO MgO melting temperature 29.6 58.1 9.3 3.0 69 1,440 low melting point

Table 7 below shows the slag discharge performance, number of gas peaks, and coal ratio indicating operation efficiency as a result of the molten iron production operation when the coal briquettes of Table 6 are applied to the molten iron production system shown in FIG.

Slag discharge gases Operation efficiency note Low slag amount (ton) Slag separation time (minutes) Gas Peak (time) Coal ratio (kg/t-p) 61 31 0.9 770 low melting point

As shown in Tables 6 and 7, the strength of the coal briquettes of Example 1 was 69%, which was lower than that of Comparative Examples 1 and 2, but it was confirmed that slag discharge was improved as a result of the molten iron manufacturing operation. In Example 1, compared to Comparative Example 1 and Comparative Example 2, the slag amount, slag separation time, and number of gas peaks were reduced, and accordingly, the operating efficiency of the melt gasification furnace was increased, and the coal ratio for producing molten iron, that is, the amount of fuel used, was reduced. appeared to have decreased.

Test example 1

Using the coal briquettes used in Comparative Example 1 and Example 1, a melt discharge characteristics experiment was performed. A mixture of iron sources and coal briquettes of a certain size was mixed into a circular crucible, and reaction gases CO, H ₂ and N ₂ were blown in at a temperature increase rate of 4°C/min, and the weight of the falling melt by gravity was measured.

Figure 3 shows the results of an experiment on melt discharge characteristics using the coal briquettes of Example 1 and Comparative Example 1 of the present invention.

Referring to Figure 3, the coal briquettes of Example 1 and Comparative Example 1 were found to start melting at 1,414°C as the reaction temperature increased, and the melting completion temperatures were 1,484°C and 1,468°C, respectively.

Here, if the time for the melt to exit the packed bed is quantitatively calculated, the melting completion temperature and melting start temperature can be calculated by dividing the temperature increase rate in the car. As a result of calculation according to the above method, in the case of the coal briquettes of Example 1, the time for the melt to exit the packed bed was 13.5 minutes, and in the case of the coal briquettes of Comparative Example 1, it was 17.5 minutes. In other words, it can be confirmed that the flowability of the melt of the coal briquettes of Example 1 was improved compared to the coal briquettes of Comparative Example 1.

Test example 2

Coal having the characteristics shown in Table 8 below and coal briquettes manufactured using the coal as raw materials were prepared and tested to measure the ash melting point of the coal and the strength of the coal briquettes. In Table 8 below, the ash component content of coal shows the ratio of the content of each component when the total sum of the four components in ash, Al ₂ O ₃ , SiO ₂ , CaO, and MgO, is set to 100.

The method for measuring batch melting point and strength has been described above and will therefore be omitted.

Here, seonghyeongtan was manufactured by the method described above.

Seonghyeongtan
division Ash content of coal (wt%) of coal
Ash melting point (℃) Seonghyeongtan
robbery(%) Al ₂ O ₃ SiO ₂ CaO MgO A 29.2 56.1 11.4 3.4 1,422 65.3 B 31.6 51.2 13.9 3.3 1,475 54.9 C 34.3 57.8 6.2 1.6 1,549 66.2 D 33.6 61.7 2.7 2.0 1,564 70.5 E 40.6 51.3 7.0 1.0 1,587 64.3 F 32.2 64.8 2.4 0.6 1,570 73.3 G 29.2 54.3 13.4 3.1 1,459 56.8 H 39.0 56.8 2.9 1.3 1,599 72.6 I 26.7 67.1 4.7 1.5 1,486 68.5 J 33.6 59.8 4.7 1.8 1,533 71.7 K 32.0 64.2 2.0 1.8 1,563 74.4 L 33.8 58.5 6.5 1.2 1,547 65.3 M 37.1 53.8 7.6 1.5 1,563 66.2 N 31.9 60.2 6.1 1.7 1,527 67.7 O 23.4 65.5 7.6 3.5 1,359 65.9 P 27.9 70.8 0.6 0.6 1,575 72.3 Q 28.2 67.0 3.1 1.7 1,525 71.2 R 33.9 54.2 9.3 2.6 1,506 65.2 S 34.3 60.7 3.7 1.4 1,570 69.6

Figure 4a shows the ash melting point according to the CaO content in the ash of coal according to an embodiment of the present invention, Figure 4b shows the ash melting point according to the Al ₂ O ₃ content, and Figure 4c shows the CaO/Al ₂ O ₃ It shows the ash melting point according to the ratio.

Referring to FIGS. 4A to 4C, as CaO in the coal ash increases, Al ₂ O ₃ decreases, and CaO/Al ₂ O ₃ value increases, the ash melting point tends to decrease.

Meanwhile, Figure 5a shows the strength of coal briquettes according to the CaO content in the ash of coal according to an embodiment of the present invention, Figure 5b shows the strength of coal briquettes according to the Al ₂ O ₃ content, and Figure 5c shows the CaO/Al ₂ This shows the strength of seonghyeongtan according to the O ₃ ratio.

Referring to Figures 5a to 5c, in order to secure the minimum strength of 60% for maintaining stable FINEX melt gasification operation, it is desirable to control the CaO content in the coal ash component to 12% or less, and CaO/Al ₂ O ₃ It can be confirmed that it is desirable to adjust the ratio to 0.5 or less.

The present invention is not limited to the above-mentioned embodiments, but can be manufactured in various different forms, and those skilled in the art may recognize other specific forms without changing the technical idea or essential features of the present invention. You will be able to understand that this can be implemented. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive.

Claims (14)

A seonghyeongtan manufacturing step of mixing coal and binder to produce seonghyeongtan;
Inject iron ore into the fluidized reduction reactor.
A reduced iron production step of producing reduced iron; and
It includes a molten iron production step of manufacturing molten iron by putting the produced reduced iron and coal briquettes into a melting gasification furnace,
The ash melting point of the coal constituting the manufactured coal briquettes is in the range of 1400 ℃ to 1550 ℃,
A method of manufacturing molten iron using reduced iron and coal briquettes.
According to paragraph 1,
The melting point of the ash of the coal is in the range of 1450 ℃ to 1500 ℃,
Method of manufacturing molten iron.
According to paragraph 1,
The mass ratio of CaO and Al ₂ O ₃ in the coal is in the range of 0.1 to 0.5.
Method of manufacturing molten iron.
(Here, the mass ratio of CaO and Al ₂ O ₃ is based on the total amount of Al ₂ O ₃ , SiO ₂ , CaO, and MgO in Ash converted to 100.)
According to paragraph 3,
The mass ratio of CaO and Al ₂ O ₃ in the coal is in the range of 0.3 to 0.4.
Method of manufacturing molten iron.
According to paragraph 1,
The CaO content in the ash of the coal is in the range of 4wt% to 12wt%,
Method of manufacturing molten iron.
According to clause 5,
The CaO content in the ash of the coal is in the range of 6wt% to 12wt%,
Method of manufacturing molten iron.
According to paragraph 1,
The Al ₂ O ₃ content in the ash of the coal is in the range of 24 wt% to 40 wt%,
Method of manufacturing molten iron.
In clause 7,
The Al ₂ O ₃ content in the ash of the coal is in the range of 24 wt% to 30 wt%,
Method of manufacturing molten iron.
According to paragraph 1,
The strength of the seonghyeongtan is in the range of 60% to 75%,
Method of manufacturing molten iron.
According to paragraph 1,
In the molten iron manufacturing step, pulverized coal is additionally added,
Method of manufacturing molten iron.
According to paragraph 1,
The seonghyeongtan manufacturing step is,
Comprising a drying step of adjusting the average moisture content of the coal in the range of 5wt% to 8wt%,
Method of manufacturing molten iron.
According to paragraph 1,
The seonghyeongtan manufacturing step is,
It includes a pretreatment step of adjusting the average particle size of the coal in the range of 2mm to 4mm,
Method of manufacturing molten iron.
According to paragraph 1,
In the stage of manufacturing seonghyeongtan,
The binder is starch made of one or more types of corn, cassava, wheat, rice, or a combination thereof,
Method of manufacturing molten iron.
According to paragraph 1,
In the stage of manufacturing seonghyeongtan,
The coal and binder are mixed and heated in the range of 70 ℃ to 130 ℃,
Method of manufacturing molten iron.