Composition for electrode rod, electrode rod, method for manufacturing the same, and method for manufacturing molten metal

Abstract

Provided are a composition for an electrode rod, an electrode rod, a method for manufacturing the electrode rod, and a method for manufacturing a molten metal, which can decelerate the oxidation rate of an electrode member. 【Means for solving the problem】 The present invention is a composition for an electrode rod for manufacturing an electrode member of an electric furnace, which may include a first carbon-based material containing artificial graphite, an oxidation prevention material containing a material having a higher reactivity with oxygen (O) than carbon (C), and a binder. Therefore, according to an embodiment of the present invention, the oxidation resistance of the electrode member provided in the electrode rod of the electric furnace can be improved, and thereby, the rate at which the electrode member is oxidized can be decelerated. Therefore, the occurrence of a penstock ring in which the diameter of the electrode member is reduced due to the oxidation reaction can be suppressed.

Description

Technical Field

[0001] The present invention relates to a composition for an electrode bar, an electrode bar, a method for manufacturing the same, and a method for manufacturing molten metal. More specifically, the present invention relates to a composition for an electrode bar, an electrode bar, a method for manufacturing the same, and a method for manufacturing molten metal, which can improve the oxidation resistance of an electrode member.

Background Art

[0002] Recently, in order to address the climate change crisis, carbon neutral technologies that substantially reduce carbon dioxide emissions to zero by reabsorbing carbon dioxide emitted by individuals, companies, organizations, etc. have been taken up as an issue. For this reason, in the steel industry, research and development have been carried out on hydrogen reduction ironmaking process technologies that produce direct reduced iron using hydrogen instead of fossil fuels that generate carbon dioxide, and use this to produce iron. When the hydrogen reduction ironmaking process technology reaches the commercialization level, this technology can replace not only the blast furnace process that generates a large amount of carbon dioxide by utilizing the electric furnace process, but also the converter process.

[0003] An electric furnace is a device that applies electric power to an electrode bar and melts iron raw materials such as reduced iron and scrap using the heat and arc generated from the electrode bar. And there is an electric furnace that uses a self-baking electrode bar as the electrode bar. The self-baking electrode bar is an electrode bar provided by charging a composition for an electrode bar containing carbon (C) into a cylindrical case fitted in an electric furnace and firing the composition for an electrode bar using the heat inside the electric furnace and the electric power applied to the case.

[0004] On the other hand, the electrode bar may be oxidized by the air flowing into the electric furnace and the oxidizing gas generated inside. And there is a possibility that "penciling" occurs, in which the diameter of the electrode bar becomes smaller due to such an oxidation reaction.

[0005] If the electrode rod is bent, the generation of heat from the electrode rod is reduced, and the area where an arc occurs around the electrode rod decreases. Therefore, there is a risk of a decrease in the operation efficiency of melting the iron raw material to produce molten metal. In addition, when the electrode rod is bent, the risk of breakage of the electrode rod during operation increases, and the breakage of the electrode rod becomes a factor that interrupts the operation or reduces the operation efficiency.

[0006] And in order to reduce such bending of the electrode rod, it becomes necessary to increase the amount of the composition for the electrode rod introduced into the case of the electrode rod or to shorten the introduction cycle. In such a case, there is a problem that the cost for producing the composition for the electrode rod increases.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention provides a composition for an electrode rod capable of reducing the oxidation rate of an electrode member, an electrode rod, a method for manufacturing the electrode rod, and a method for manufacturing molten metal.

[0009] The present invention provides a composition for an electrode rod capable of improving electrical characteristics, an electrode rod, a method for manufacturing the electrode rod, and a method for manufacturing molten metal.

Means for Solving the Problems

[0010] An embodiment of the present invention is a composition for an electrode rod for manufacturing an electrode member of an electric furnace, which may include a first carbon-based material containing artificial graphite, an antioxidant material containing a material having a higher reactivity with oxygen (O) than carbon (C), and a binder.

[0011] The content of the first carbon-based material in the total weight of the composition for the electrode rod may be 50 wt% to 65 wt%, the content of the antioxidant material may be 1 wt% to 7 wt%, and the content of the binder may be 30 wt% to 43 wt%.

[0012] The composition for the electrode rod may include a second carbon-based material including at least one of natural graphite and coke.

[0013] The content of the first carbon-based material in the total weight of the composition for the electrode rod may be 50 wt% to 60 wt%, the content of the antioxidant material may be 1 wt% to 5 wt%, the content of the binder may be 30 wt% to 40 wt%, and the content of the second carbon-based material may be 1 wt% to 5 wt%.

[0014] As the first carbon-based material, waste containing artificial graphite may be used.

[0015] The antioxidant material may include at least one of metal Al and metal Si.

[0016] The first and second carbon-based materials are provided in a solid state including a plurality of particles, the antioxidant material is provided in a liquid state, and the antioxidant material may be coated on the surface of the particles of the first carbon-based material.

[0017] The present invention includes an electrode rod partially fitted into the main body of an electric furnace, a case having an internal space extending in one direction, and a briquette including a first carbon-based material including artificial graphite, an antioxidant material including a material having a higher reactivity with oxygen (O) than carbon (C), and a binder, which is put into the case and fired to form an electrode member, a part of which is located inside the case and the rest of which is formed to protrude outside the lower side of the case.

[0018] The antioxidant material may include at least one of metal Al and metal Si.

[0019] The briquette may contain a second carbon-based material including at least one of natural graphite and coke.

[0020] The method for manufacturing the electrode bar of the present invention includes a process of manufacturing a briquette including a first carbon-based material containing artificial graphite, an antioxidant material having a higher reactivity with oxygen (O) than carbon (C), and a binder, a process of charging the briquette into the inside of a case of an electrode bar fitted in the main body of an electric furnace, and a process of firing the briquette using heat inside the main body and electric power applied to the case to form an electrode member.

[0021] The process of manufacturing the briquette may include a process of mixing the first carbon-based material, the antioxidant material, and the binder to prepare a composition for an electrode bar, and a process of granulating the composition for the electrode bar.

[0022] The process of manufacturing the briquette may include a process of coating the surface of particles of the first carbon-based material with the antioxidant material, a process of mixing the first carbon-based material coated with the antioxidant material and the binder to prepare a composition for an electrode bar, and a process of granulating the composition for the electrode bar.

[0023] The process of preparing the composition for the electrode bar may include a process of preparing a second carbon-based material including at least one of natural graphite and coke, and a process of mixing the first carbon-based material, the antioxidant material, the binder, and the second carbon-based material.

[0024] The process of preparing the composition for the electrode bar may include a process of preparing a second carbon-based material including at least one of natural graphite and coke, and a process of mixing the first carbon-based material coated with the antioxidant material, the binder, and the second carbon-based material.

[0025] The method for manufacturing a molten metal according to the present invention may include a process of charging raw materials into the interior of the main body of an electric furnace, a process of charging briquettes containing a first carbon-based material containing artificial graphite, an antioxidant material having a higher reactivity with oxygen (O) than carbon (C), and a binder into the interior of a case of an electrode rod that is fitted so that a part thereof is located inside the main body, a process of firing the briquettes inside the case to form an electrode member, a part of which is located inside the case and the rest of which protrudes outside the lower side of the case, and a process of applying electric power to the electrode rod to generate heat and melt the raw materials.

[0026] The method for manufacturing a molten metal may include a process of reacting the antioxidant material contained in the electrode member with oxygen (O) prior to reacting carbon (C) contained in the electrode member with oxygen (O).

[0027] The process of reacting the antioxidant material with oxygen (O) may include a process of reacting at least one of Al and Si contained in the antioxidant material with oxygen (O).

[0028] The raw materials may include hydrogen direct reduced iron reduced by hydrogen.

Advantages of the Invention

[0029] According to the present invention, the oxidation resistance of the electrode member provided on the electrode rod of the electric furnace can be improved, and thereby the rate at which the electrode member is oxidized can be reduced. Therefore, the occurrence of a penstock ring in which the diameter of the electrode member is reduced due to the oxidation reaction can be suppressed.

[0030] In addition, it is possible to suppress a decrease in the area and temperature where heat is generated from the electrode member due to the penstock ring, and a decrease in the region where an arc is generated around the electrode member. Thereby, when melting the raw materials with heat and arc generated from the electrode member to manufacture a molten metal, the operation efficiency can be improved.

[0031] And, by improving the oxidation resistance of the electrode member, the life of the electrode member can be improved. Therefore, the amount of the composition for the electrode rod charged into the case to form the electrode member during the operation of the electric furnace can be reduced, and the charging cycle can be lengthened. Accordingly, there is an effect that the cost for charging the composition for the electrode rod is saved.

[0032] Also, the electrical resistivity of the electrode member can be lowered. Therefore, the efficiency of generating heat and arc from the electrode rod by the applied electric power can be increased.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0034] Hereinafter, the present invention will be described in more detail based on the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and can be embodied in various different forms. The following embodiments are provided only to make the disclosure of the present invention complete and to fully inform those with ordinary knowledge of the scope of the invention. The drawings may be exaggerated for the purpose of explaining the embodiments of the present invention, and the same reference numerals in the drawings refer to the same components.

[0035] FIG. 1 is a diagram schematically showing an electric furnace equipped with an electrode rod of the present invention.

[0036] An electric smelting furnace apparatus is an apparatus for melting raw material M charged therein to produce a melt, i.e., molten metal L. As shown in FIG. 1, the electric furnace may include a main body 100 having an internal space capable of processing raw material M, an electrode rod 200 disposed such that at least a part thereof is located inside the main body 100 to generate heat for melting raw material M, and a power supply unit 300 connected to the electrode rod 200 so as to apply power. Further, the electric furnace may include a raw material supply unit 400 disposed so as to be connected to the main body 100 so that raw material M can be charged.

[0037] The raw material M charged into the internal space of the main body 100 may include a first raw material M1 and a second raw material M2. The first raw material M1 may include, for example, direct reduced iron (DRI). The second raw material M2 may include a reducing agent. More specifically, the second raw material M2 may include coke. Inside the main body 100, the first raw material M1 and the second raw material M2 are melted by the heat generated from the electrode rod 200, and the first raw material M1 is reduced by the second raw material M2, whereby molten metal L is produced.

[0038] The direct reduced iron may be at least one of low-grade direct reduced iron produced using ores with an iron (Fe) content of less than 65 wt% before reduction and high-grade direct reduced iron produced using ores with an iron (Fe) content of 65 wt% or more before reduction. And the direct reduced iron (DRI) as the first raw material M1 may be direct reduced iron reduced using hydrogen, that is, "hydrogen direct reduced iron". Therefore, an electric furnace that melts and reduces the hydrogen direct reduced iron as the first raw material M1d to produce molten metal can be named an "electric furnace for melting hydrogen-reduced direct reduced iron".

[0039] In the above, it was explained that the first raw material M1 charged into the electric furnace contains hydrogen direct reduced iron. However, the first raw material M1 may contain direct reduced iron produced by reduction by various methods in addition to direct reduced iron reduced using hydrogen.

[0040] Also, the first raw material M1 is not limited to direct reduced iron and may contain scrap with a higher iron (Fe) content than the direct reduced iron. The scrap may be iron scrap with an iron (Fe) content exceeding 70 wt%, more preferably iron scrap with an iron (Fe) content of 85 wt% to 99 wt%.

[0041] The main body 100 may include a furnace body 110 having an internal space and a lid 120 covering an opening provided above the furnace body 110.

[0042] The furnace body 110 may have an internal space and be cylindrical with an open upper side. Such a furnace body 110 may include an outer wall body 110A made of iron sheet or metal and an inner wall body 110B built from a refractory material so as to surround the inner wall of the outer wall body 110A.

[0043] The furnace body 110 may be provided with a first discharge port 111 for discharging the molten metal L and a second discharge port 112 for discharging the slag S floating on the upper part of the molten metal L. Each of the first and second discharge ports 112 may be provided on the side wall of the furnace body 110, or may be provided on the bottom surface of the lower part of the furnace body 110. Taking FIG. 1 as an example, the first discharge port 111 may be provided on the side wall on one side of the furnace body 110, and the second discharge port 112 may be provided on the side wall on the other side of the furnace body 110. Needless to say, the first and second discharge ports 111 and 112 are not limited to the above-described positions at all, and may be provided at various positions where the molten metal L and the slag S can be discharged to the outside.

[0044] Outside the furnace body 110, containers 10a and 10B capable of accommodating the molten metal L and the slag S respectively are arranged. That is, the first container 10A may be arranged below the first discharge port 111 on the outside of the furnace body 110, and the second container 10B may be arranged below the second discharge port 112. Here, the first container 10A for accommodating the molten metal L discharged from the first discharge port 111 may be, for example, a ladle, and the second container 10B for accommodating the slag S discharged from the second discharge port 112 may be a slag port.

[0045] The lid body 120 is disposed above the furnace body 110 so as to be able to close the opening on the upper side of the furnace body 110. At this time, the lid body 120 may be made of a refractory. Further, the lid body 120 may be provided with a hole through which a part of the electrode rod 200 can pass and a hole through which a part of the raw material supply unit 400 can pass. In addition, the lid body 120 may be further provided with an inlet through which the raw material M can be charged.

[0046] The raw material supply unit 400 is a means for supplying the raw material M to the main body 100 of the electric furnace. Such a raw material supply unit 400 may include, for example, a first hopper 410 storing the first raw material M1, a second hopper 420 storing the second raw material M2, and a feeder 430 connected to the first and second hoppers 410 and 420 so that the first and second raw materials M1 and M2 can be charged into the main body 100.

[0047] The feeder 430 may include, for example, a first transfer pipe 431 connected to the first hopper 410, a second transfer pipe 432 connected to the second hopper 420, and a third transfer pipe 433 having one end connected to the first and second transfer pipes 431 and 432 and the other end disposed through the lid 120 so as to be located in the internal space of the main body 100. Further, a valve may be disposed in at least one of the first transfer pipe 431, the second transfer pipe 432, and the third transfer pipe 433.

[0048] In the above, it has been described that the raw material supply unit 400 includes the first and second hoppers 410 and 420. However, the present invention is not limited thereto, and it may further include a hopper in which raw materials different from the first and second raw materials M1 and M2 are stored.

[0049] Also, the raw material M is not limited to being input using the raw material supply unit 400 as described above, and may be input into the main body 100 through an input port provided in the lid 120.

[0050] FIG. 2 is a cross-sectional view showing a state in which the electrode bar according to the embodiment of the present invention is fitted into the main body of the electric furnace.

[0051] The electrode bar 200 generates heat and an arc by the applied electric power to supply heat into the main body 100. Here, the electric power may mean voltage or current, and the heat generated from the electrode bar 200 may include resistance heat due to the applied electric power. Then, the heat and arc supplied into the main body 100 by the electrode bar 200 melt or dissolve the raw material M, and thus, a melt, that is, molten metal is produced.

[0052] A plurality of electrode bars 200 may be provided. For example, as shown in FIG. 1, three electrode bars 200a, 200b, and 200c may be provided. And a plurality of electrode bars 200a, 200b, and 200c may be connected to one power supply unit 300.

[0053] In the above description, it has been explained that a plurality of electrode rods 200a, 200b, and 200c are connected to one power supply unit 300. However, the present invention is not limited thereto, and a plurality of power supply units 300 may be provided so as to be connected to the plurality of electrode rods 200a, 200b, and 200c on a one-to-one basis. Further, the number of electrode rods is not limited to the above-described example, and may be provided as one, or may be provided in a number of three or more.

[0054] Hereinafter, the configuration of the electrode rod will be described. At this time, the plurality of electrode rods 200a, 200b, and 200c are provided with the same configuration and shape. Therefore, one electrode rod will be described as an example, and for ease of explanation, it will be described with “200” attached as the drawing reference numeral of the electrode rod.

[0055] As shown in FIG. 2, the electrode rod 200 may include a case 210 having an internal space, an electrode member 220 formed such that a part thereof is inserted into the case 210 to generate heat by power and the remainder protrudes outside the case 210, and a power supply member 230 attached to the case 210 so as to supply power to the case 210. Further, the electrode rod 200 may include a lifter (not shown) connected to the case 210 so that the case 210 can be lowered or raised.

[0056] As shown in FIG. 1, the electrode rod 200 is disposed such that a part thereof is located inside the main body 100 and the remainder is located outside the main body 100. That is, the electrode rod 200 may be disposed so as to penetrate the lid 120 in the vertical direction and a part thereof is located inside the furnace body 110. For this reason, a part of the electrode rod 200 is located below the lid 120 and accommodated inside the furnace body 110, and the other part protrudes above the lid 120 and is located outside the furnace body 110. Then, the height of the electrode rod 200 is adjusted so that its lower part is immersed in the slag S floating on the upper part of the molten metal or buried in the raw material M accumulated on the upper part of the slag S.

[0057] The case 210 may be cylindrical with an internal space. That is, the case 210 may have an internal space extending in the vertical direction and may be in the shape of a tube with openings on the upper and lower sides. The shape of the case 210 is not particularly limited, and for example, it may be in the shape of a cylinder with a circular cross-sectional shape. And the case 210 may be made of metal.

[0058] As described above, part of the electrode rod 200 is located inside the furnace body 110, and the rest is arranged to be located outside the furnace body 110. For this purpose, the case 210 is arranged to penetrate the lid 120 in the vertical direction so that part of it is located inside the furnace body 110 and the rest can be located outside the furnace body 110.

[0059] The power supply member 230 is a means for transmitting the power transmitted from the power supply unit 300 to the case 210. Such a power supply member 230 may be arranged on the case 210 so as to be located outside the main body 100, that is, above the lid 120, as shown in FIG. 2. The material of the power supply member 230 is not particularly limited as long as it is a conductor capable of transmitting power, and for example, it may be prepared as a material containing copper (Cu).

[0060] And a power supply line 310 may be connected between the power supply unit 300 and the power supply member 230. For this reason, the power output from the power supply unit 300 can be transmitted to the power supply member 230 via the power supply line 310. Also, the power transmitted to the power supply member 230 can be transmitted to the electrode member 220 inside the case 210 after being transmitted to the case 210.

[0061] As shown in FIG. 2, the electrode member 220 is connected to the case 210 such that a part thereof can protrude outside the lower side of the case 210. That is, the electrode member 220 is connected such that a part thereof is located inside the case 210 and the rest protrudes outside the case 210. Such an electrode member 220 is made of a material containing carbon (C) and generates resistive heat when power is applied. Also, at this time, an arc may be generated around the electrode member 220.

[0062] The electrode member 220 is a self-firing electrode manufactured by firing a material introduced into the case 210. Hereinafter, for ease of explanation, the material introduced into the case of the electrode rod 200 to manufacture or form the electrode member 220 is named "composition for electrode rod".

[0063] The electrode member 220 is not connected to the case 210 in a state where it is manufactured in a predetermined shape, for example, a rod shape. Instead, the composition for the electrode rod is introduced into the case 210, and the introduced composition for the electrode rod is provided by being fired by heat.

[0064] On the other hand, when the power transmitted to the case 210 is transmitted to the electrode member 220, heat is generated from the electrode member 220, and an arc is generated around the electrode member 220. For this reason, the first and second raw materials M1, M2 inside the main body 100 are melted to produce molten metal L. At this time, the electrode member 220 is oxidized by the air flowing into the main body 100 and the oxidizing metal generated inside the main body 100, and at least one of the length and diameter of the electrode member 220 decreases due to the dioxide reaction. That is, the electrode member 220 is consumed. Also, the electrode member 220 may be consumed by the arc generated from around the electrode member 220. Thus, the electrode member 220 is a consumable electrode in which at least one of the length and diameter decreases due to oxidation reaction and arc.

[0065] Therefore, in order to continuously or continuously form the electrode member 220 while operating the electric furnace, a composition for an electrode rod for forming the electrode member 220 is introduced into the case 210. The introduced composition for the electrode rod undergoes a softening, melting, and firing reaction inside the case 210 to become the solid-phase electrode member 220.

[0066] The composition for the electrode rod may include a carbon (C)-containing material and a binder. The carbon-containing material may be in the form of particles or powder with a small particle size. The carbon (C)-containing material and the binder are mixed, formed into briquettes (or pea coal) B, and the produced briquettes B are introduced into the case 210.

[0067] When the briquette B is introduced into the case 210, the briquette B is fired, and thus the electrode member 220 is manufactured. That is, when power is supplied to the case 210 via the power supply unit 300 and the power supply member 230, the power is transmitted to the briquette B introduced into the case 210. For this reason, resistive heat is generated from the briquette B, and thus the briquette is softened. Then, the softened briquette is melted or fused by the generation of resistive heat due to the continuously supplied power, and thereafter, it is manufactured into the electrode member 220 in a solid state through a firing reaction.

[0068] The region inside the main body 100 of the case 210 can be melted and disappear over time because its temperature is high. That is, the lower part of the case 210 adjacent to the bottom surface of the main body 100 of the case 210 fitted inside the main body 100 is melted and disappeared. For this reason, the case 210 is lowered over time while operating the electric furnace.

[0069] Also, as described above, the electrode member 220 protruding downward from the case 210 is consumed. Therefore, while gradually lowering the case 210 over time, a briquette B manufactured by granulating the composition for the electrode bar is put into the case 210. As a result, it becomes possible for the electrode member 220 to be continuously formed while the electric furnace is operating, and the electrode member 220 can protrude downward from the case 210.

[0070] And for this purpose, in order to continuously put the briquette B into the case 210 as described above, the internal space of the case 210 has a briquette zone Z from the upper side where the briquette B is put in to the lower side br , a softening zone Z s , a melting zone Z m , a baking zone Z ba divided into. That is, the upper space of the electrode member 220 inside the case 210 is the briquette zone Z where the input briquette B and the briquette are kept in a solid phase state br , a softening zone Z where the briquette is softened by heat s , a melting zone Z where the softened briquette is melted m , a baking zone Z where the melted briquette is baked ba divided into. In other words, the internal space of the case 210 can be described as including the briquette zone Z br , the softening zone Z s , the melting zone Z m and the baking zone Z ba . At this time, when the briquette B finishes softening, melting, and baking, the electrode member 220 is prepared, so it can be explained that the electrode member 220 is connected to the lower part of the baking zone Z ba .

[0071] Figure 3(a) is a photograph of the state before the electrode member of the electrode bar is penciled, and Figure 3(b) is a photograph of the state where the electrode member is penciled.

[0072] As described above, the electrode member 220 contains carbon (C). And carbon (C) is easily oxidized with oxygen (O). For this reason, it can undergo an oxidation reaction with the air flowing into the interior of the main body 100 of the electric furnace and the oxidizing gas generated inside the main body 100, such as CO 2 (carbon dioxide), etc. Also, when power is applied and heat is generated from the electrode member 220, an arc may be generated together. For this reason, the electrode member 220 may be consumed by the oxidation reaction and the arc. That is, there is a possibility that penciling, where the diameter of the electrode member 220 decreases, may occur. Referring to FIGS. 3(a) and 3(b) for explanation, the diameter D of the electrode member 220 before penciling occurs due to the oxidation reaction and the arc 1 is larger than the diameter D of the electrode member 220 after penciling occurs 2 (D 1 >D 2 ). At this time, compared with the consumption of the electrode member 220 by the arc, the consumption of the electrode member 220 by the oxidation reaction is even greater.

[0073] Thus, when penciling occurs, where the diameter of the electrode member 220 decreases, there is a possibility that the area where heat is generated from the electrode member 220 may decrease, and the region where an arc is generated around the electrode member 220 may decrease. For this reason, when manufacturing the molten metal L by melting the raw material M using the heat and arc generated from the electrode member 220, there is a possibility that the operation efficiency may decrease.

[0074] Therefore, it is necessary to improve the oxidation resistance of the electrode member 220 so that the oxidation reaction is suppressed or prevented. In other words, it is necessary to manufacture the electrode member 220 with improved oxidation resistance. For this purpose, in the embodiment, the electrode member 220 is manufactured using a first carbon-based material containing artificial graphite. That is, the composition for the electrode rod for manufacturing the electrode member 220 contains a first carbon-based material, and the first carbon-based material contains artificial graphite. Further, the composition for the electrode rod contains an antioxidant material and a binder containing a material having better oxidation properties than carbon (C). And the composition for the electrode rod may further contain a second carbon-based material different from the first carbon-based material.

[0075] In short, the composition for the electrode rod may contain, as shown in Table 1, a first carbon-based material containing artificial graphite, an antioxidant material containing a material having better oxidation properties than carbon (C), and a binder (First Example). At this time, the first carbon-based material may be contained in an amount of 50 wt% to 65 wt%, the antioxidant material may be contained in an amount of 1 wt% to 7 wt%, and the binder may be contained in an amount of 30 wt% to 43 wt%.

[0076]

Table 1

[0077] Further, the composition for the electrode rod may more preferably further contain a second carbon-based material containing at least one of natural graphite and coke (Second and Third Examples). That is, the composition for the electrode rod according to the second example may contain natural graphite, and the composition for the electrode rod according to the third example may contain coke. Here, the natural graphite used as the second carbon-based material functions to improve the electrical conductivity of the electrode member 220, and coke functions to improve the strength of the electrode member 220.

[0078] At this time, the first carbon-based material may be contained in an amount of 50 wt% to 60 wt%, the antioxidant material may be contained in an amount of 1 wt% to 5 wt%, the second carbon-based material may be contained in an amount of 1 wt% to 5 wt%, and the binder may be contained in an amount of 30 wt% to 40 wt%.

[0079] In addition, the second carbon-based material of the composition for the electrode rod may contain both natural graphite and coke (the fourth embodiment). In such a case, the content of each of natural graphite and coke is 1 wt% to 5 wt%, and the sum of the content of natural graphite and the content of coke is adjusted to be in the range of 1 wt% to 5 wt%.

[0080] Thus, the first carbon-based material in the composition for the electrode rod according to the embodiment is 50 wt% to 65 wt% or 50 wt% to 60 wt%, and is mixed at the highest content. Therefore, among the materials contained in the composition for the electrode rod, it can be explained that the first carbon-based material is the main material.

[0081] On the other hand, the conventional composition for the electrode rod uses anthracite as the carbon-based material. That is, the conventional composition for the electrode rod contains anthracite and a binder, the anthracite is contained in an amount of 60 wt% to 70 wt%, and the binder is contained in an amount of 30 wt% to 70 wt%. However, anthracite has low crystallinity and many cracks and pores, so the oxidation rate is fast.

[0082] In contrast, graphite has a hexagonal crystal system and high crystallinity. More specifically, graphite has a hexagonal plate-like crystal structure. And artificial graphite has higher mechanical strength than natural graphite. Therefore, in the embodiment, graphite is used as the carbon-based material. More specifically, artificial graphite is used as the first carbon-based material which is the main material. In other words, without using anthracite which has been used as the carbon-based material that is the main material conventionally, artificial graphite is used as a substitute for anthracite.

[0083] Figure 4(a) shows the X-ray diffraction (XRD) analysis result of anthracite, and Figure 4(b) shows the XRD (X-ray diffraction) analysis result of artificial graphite.

[0084] Hereinafter, with reference to Figure 4, the crystallinity of anthracite and artificial graphite will be described.

[0085] For XRD analysis, a sample made of anthracite and a sample made of artificial graphite were prepared respectively. Then, XRD analysis was performed on each sample, and the results are as shown in Figure 4.

[0086] In the XRD analysis results, the higher the intensity of the highest peak with the largest intensity, and the smaller the half-width of the highest peak, the higher the crystallinity. Referring to Figures 4(a) and (b), when comparing the intensity of the highest peak, the intensity of the highest peak of artificial graphite (Figure 4(b)) is even higher than that of anthracite (Figure 4(a)). More specifically, in the case of anthracite, the intensity of the highest peak is as low as 1,300 (cps: counts per second), while in the case of artificial graphite, the intensity of the highest peak is about 220,000 (cps), which is more than 160 times higher than that of anthracite. Also, when comparing the half-width of the highest peak, the half-width of artificial graphite is even narrower than that of anthracite.

[0087] And the crystal thickness and crystal length can be calculated from the XRD results such as those in Figures 4(a) and (b). In the case of anthracite calculated from the results in Figure 4(a), the crystal thickness is 30 Å - 80 Å, and the crystal length is 50 Å - 120 Å. In contrast, in the case of artificial graphite calculated from the results in Figure 4(b), the crystal thickness is 280 Å - 350 Å, and the crystal length is 150 Å - 200 Å. That is, the crystal thickness and crystal length of artificial graphite are larger than those of anthracite. From this, it can be seen that the crystallinity of artificial graphite is higher than that of anthracite.

[0088] Thus, the crystallinity of artificial graphite is even higher than that of anthracite. And the higher the crystallinity, the more stable it is, so the reactivity with other components is lower. Therefore, it can be seen that the oxidation reactivity of artificial graphite is even lower than that of anthracite.

[0089] And in the case of natural graphite as well, like artificial graphite, it has a hexagonal plate-like crystal structure. For this reason, natural graphite has a higher crystallinity compared to anthracite. And such natural graphite has a lower mechanical strength compared to artificial graphite.

[0090] Figure 5 shows the experimental results regarding the oxidation rates of anthracite and artificial graphite.

[0091] Hereinafter, with reference to Figure 5, the oxidation rates of anthracite and artificial graphite will be described. In order to examine the oxidation rates of anthracite and artificial graphite, a thermogravimetric analysis experiment was conducted. For this purpose, the experiment was carried out as follows. First, a first specimen made from anthracite and a second specimen made from artificial graphite were prepared. Then, the first and second specimens were introduced into a heating furnace whose temperature was adjusted to 700 °C, and air was supplied to the heating furnace. After that, the weights (masses) of the first and second specimens as time elapsed were measured, the weight change rate was calculated, and the results are shown in Figure 5. Here, the weight reduction rate may be the ratio of the weight (W 1 ) of the specimen after being introduced into the heating furnace to the weight (W 2 ) of the specimen before being introduced into the heating furnace (see Equation 1).

[0092]

Equation

[0093] As shown in Figure 5, compared to the rate at which the weight of the first specimen (anthracite) decreases, the rate at which the weight of the second specimen (artificial graphite) decreases is even slower. From this, it can be understood that when using artificial graphite compared to using anthracite as the composition for the electrode rod, the rate at which the electrode member 220 is oxidized can be slowed down. That is, it can be understood that when using artificial graphite compared to using anthracite as the composition for the electrode rod, the oxidation resistance of the electrode member 220 can be improved.

[0094] Figure 6 is an Ellingham diagram showing the reactivity with oxygen for each metal material.

[0095] As an anti-oxidation material, a material with better reactivity with oxygen (O) than carbon (C) is used. In other words, a material that reacts with oxygen preferentially over the oxidation reaction between carbon (C) and oxygen (O) and can delay the oxidation reaction of carbon is used as the anti-oxidation material.

[0096] As shown in FIG. 6, materials with higher reactivity with oxygen, that is, higher oxygen affinity than carbon (C) include Zn, Cr, Mn, Si, Ti, Al, Mg, and Ca. Among them, it is preferable to use at least one of Al and Si as the anti-oxidation material. This is because in the case of the molten metal L produced in the electric furnace, the content of at least one of Al and Si must be adjusted to a predetermined amount or more. And Al and Si used as the anti-oxidation material may be metals. That is, they may be Al and Si in a metallic state rather than oxides, carbides, or nitrides. In other words, metallic Al and metallic Si with a purity of 95% or more, more preferably 99% or more, may be used.

[0097] Thus, in the embodiment, as the anti-oxidation material, a material with better oxygen affinity than carbon (C), that is, a material with good oxidation reactivity, is used. Therefore, compared with the carbon (C) contained in the electrode member 220, the anti-oxidation material, for example, at least one of Al and Si reacts preferentially with oxygen. Thereby, the oxidation reaction of the carbon (C) contained in the electrode member 220 can be delayed. Here, the carbon (C) contained in the electrode member 220 may be contained in artificial graphite, which is the first carbon-based material, and natural graphite, which is the second carbon-based material. And the first carbon-based material in the composition for the electrode rod for manufacturing the electrode member 220 is contained in a large amount of 50 wt% to 65 wt% or 50 wt% to 60 wt%, and the second carbon-based material containing natural graphite is contained at 1 wt% to 5 wt%. Also, the total amount of the first and second carbon-based materials is 51 wt% to 65 wt%. Therefore, the electrode member 220 contains a large amount of carbon (C) compared with other components.

[0098] Therefore, when suppressing or delaying the oxidation reaction of carbon (C) among the components contained in the electrode member 220, the oxidation of the electrode member 220 can be effectively suppressed.

[0099] FIG. 7 is a flowchart for explaining a method of manufacturing a briquette by the method according to an embodiment of the present invention. FIG. 8 is a micrograph of the microstructure of a briquette manufactured by the method according to a second example of the present invention.

[0100] For the production of the briquette B, first, a composition for an electrode bar is produced (S10). That is, a first carbon-based material (S11) containing artificial graphite, an antioxidant material (S12), and a binder (S14) are prepared. Then, the first carbon-based material, the antioxidant material, and the binder are mixed (S15). Thus, a composition for an electrode bar is produced (S10). That is, a composition for an electrode bar according to the first example is produced. At this time, each of the first carbon-based material, the antioxidant material, and the second carbon-based material may be in a solid phase state including solid powder or a plurality of particles.

[0101] And the composition for an electrode bar may further contain a second carbon-based material (S13) including at least one of natural graphite and coke. Thus, it is possible to produce a composition for an electrode bar (second and third examples) by further including the second carbon-based material (S13) in the first carbon-based material, the antioxidant material, and the binder.

[0102] The artificial graphite may be manufactured by adding a binder to pitch coke or petroleum coke and then subjecting it to heat treatment at a high temperature to graphitize it. In other words, the artificial graphite may be obtained by processing pitch coke or petroleum coke.

[0103] As for the artificial graphite used as the first carbon-based material, those newly processed and manufactured by the method as described above may be used, or the discarded artificial graphite (waste artificial graphite) may be recycled. Here, the waste artificial graphite may be recovered from the electrodes for electrical discharge machining or the crucibles and heaters of silicon wafer (Si wafer) growth apparatuses. First, regarding the electrodes for electrical discharge machining, electrical discharge machining is performed when manufacturing a mold. At this time, an electrode made of artificial graphite is used as the electrode for electrical discharge machining. And the crucibles and heaters provided in the silicon wafer growth apparatus are manufactured from artificial graphite. For this reason, artificial graphite is recovered from at least one of the discarded electrodes for electrical discharge machining, crucibles, and heaters and used as the first carbon-based material. To give another example, artificial graphite, which is waste generated during the manufacture of at least one of the electrodes for electrical discharge machining, crucibles, and heaters, can be recovered and used as the first carbon-based material. In this way, by recycling the waste artificial graphite as the first carbon-based material, the cost for manufacturing the electrode rods or electrode members can be reduced.

[0104] The oxidation prevention material may be at least one of Al and Si. And the binder may contain coal tar pitch and may further contain a phenolic resin.

[0105] When mixing (S15) the first carbon-based material, the oxidation prevention material, and the binder to prepare the composition for the electrode rod according to the first embodiment, they are mixed so that the first carbon-based material is contained at 50 wt% to 65 wt%, the oxidation prevention material is contained at 1 wt% to 7 wt%, and the binder is contained at 30 wt% to 43 wt% (see Table 1).

[0106] Then, when preparing the composition for the electrode rod according to the second and third embodiments by mixing a second carbon-based material in addition to the first carbon-based material, the antioxidant material, and the binder (S15), the mixture is carried out such that the first carbon-based material is contained at 50 wt% to 60 wt%, the antioxidant material is contained at 1 wt% to 5 wt%, the binder is contained at 30 wt% to 40 wt%, and the second carbon-based material is contained at 1 wt% to 5 wt% (see Table 1).

[0107] In the case of the second embodiment, a material containing natural graphite is used as the second carbon-based material. In the case of the third embodiment, a material containing coke is used as the second carbon-based material. Further, in the case of the second embodiment, coal tar pitch can be used as the binder. In the case of the third embodiment, coal tar pitch and phenol resin can be mixed and used. At this time, in the binder according to the third embodiment, coal tar pitch may be contained at 60 wt% to 70 wt% and phenol resin may be contained at 30 wt% to 40 wt% in the total weight of the binder.

[0108] On the other hand, when the content of the first carbon-based material in the composition for the electrode rod is less than 50 wt%, the resistance of the electrode member 220 may be high or the strength may be weak. Conversely, when the content of the first carbon-based material in the composition for the electrode rod exceeds 65 wt%, the content of at least one of the antioxidant material, the second carbon-based material, and the binder decreases, so that the effect of reducing the oxidation rate of the electrode member 220 may be subtle, the resistance may be high, or the strength may be weak.

[0109] When the content of the antioxidant material is less than 1 wt%, the effect of reducing the oxidation rate of the electrode member 220 may be subtle. And in the range where the content of the antioxidant material exceeds 7 wt%, the effect of delaying the oxidation reaction of carbon (C) contained in the electrode member 220 may be subtle. Further, in order to produce the molten metal having the target component content, the content of the antioxidant material in the composition for the electrode rod must be contained at 7 wt% or less. Therefore, the mixture is carried out such that the antioxidant material is contained at 1 wt% to 7 wt%.

[0110] When the binder is contained at less than 30 wt%, the strength of the briquette may be weak. Conversely, when the content of the binder exceeds 43 wt%, since the content of other materials relatively decreases, there is a risk that the specific resistance of the electrode member increases, the oxidation rate becomes large, or the strength decreases.

[0111] Therefore, a composition for an electrode rod is prepared by mixing so as to contain 50 wt% to 65 wt% of a first carbon-based material, 1 wt% to 7 wt% of an antioxidant material, and 30 wt% to 43 wt% of a binder.

[0112] And the composition for the electrode rod may further contain a second carbon-based material. At this time, the second carbon-based material is mixed so as to be contained at 1 wt% to 5 wt%, and the second carbon-based material may contain at least one of natural graphite and coke. At this time, in order to further improve the electrical conductivity of the electrode member 220, a second carbon-based material containing natural graphite is used, and in order to improve the strength of the electrode member 220, a second carbon-based material containing coke is used.

[0113] When using a second carbon-based material containing natural graphite, for example, when the second carbon-based material is contained at less than 1 wt%, the effect of improving the electrical conductivity of the electrode member 220 may be subtle. Also, when using a second carbon-based material containing coke, for example, when the second carbon-based material is contained at less than 1 wt%, the effect of improving the strength of the electrode member 220 may be subtle. And when the content of the second carbon-based material containing at least one of natural graphite and coke exceeds 7 wt%, there is a risk of not being smoothly mixed with other materials. That is, the second carbon-based material is not mixed so as to be uniformly distributed in the composition for the electrode rod in which the first carbon-based material, the antioxidant material, the binder, and the second carbon-based material are mixed, and there is a risk of remaining in a lump on either side.

[0114] Therefore, mix so that it contains 50 wt% to 60 wt% of the first carbon-based material, 1 wt% to 5 wt% of the antioxidant material, 30 wt% to 40 wt% of the binder, and 1 wt% to 5 wt% of the second carbon-based material.

[0115] If the composition for the electrode bar is prepared, load it into a molding machine and granulate it (S20). Thereby, a briquette B having a predetermined size is manufactured.

[0116] In the above, it has been described that each of the first carbon-based material, the antioxidant material, and the second carbon-based material is prepared in a state of solid particles or powder. However, the present invention is not limited to this at all, and the antioxidant material may be prepared in a liquid state. And after coating the surface of the particles of the first carbon-based material with the liquid antioxidant material, the first carbon-based material coated with the antioxidant material may be mixed with the second carbon-based material and the binder.

[0117] The briquette B manufactured by such a method contains the first carbon-based material, the antioxidant material, and the binder. Further, the second carbon-based material may be further contained. Referring to FIG. 8, referring to the microstructure of the briquette manufactured using the composition for the electrode bar according to the second embodiment in which the second carbon-based material containing natural coke is mixed, it can be confirmed that the artificial graphite which is the first carbon-based material, the antioxidant material, and the natural graphite which is the second carbon-based material are contained.

[0118] If the briquette B is manufactured, put it into the inside of the case 210 of the electrode bar 200 disposed in the main body 100 of the electric furnace. That is, as shown in FIG. 2, put the briquette B into the upper opening of the case 210.

[0119] The briquette B introduced into the interior of the case 210 undergoes the processes of softening, melting, and firing in this order due to the electric power applied to the case 210 via the power supply member 230 and the heat inside the main body 100, and thus, the electrode member 220 is formed. At this time, a part of the electrode member 220 may extend so as to protrude outside the lower side of the case 210.

[0120] The first and second raw materials M1 and M2 loaded into the interior of the main body 100 are melted or dissolved by the heat generated from the electrode member 220 and the arc generated around the electrode member 220, and thereby, the molten metal L is produced. Then, the produced molten metal L is discharged through the first discharge port 111 and then loaded into the first container 10A.

[0121] Table 2 shows the characteristics of the electrodes manufactured by the methods according to the first to third experimental examples. The first experimental example is an electrode manufactured using a composition for an electrode rod containing anthracite and a binder. The second experimental example is an electrode manufactured using the composition for an electrode rod according to the second embodiment of the present invention, and the third experimental example is an electrode manufactured using the composition for an electrode rod according to the third embodiment of the present invention.

[0122] For the experiment, compositions for electrode rods according to the first to third experimental examples were prepared, granulated, and briquettes were manufactured. Then, the briquettes according to the first to third experimental examples were heat-treated and fired to manufacture electrode members. At this time, the briquettes according to the first to third experimental examples were heated at the same temperature and for the same period of time.

[0123] Then, the density (g / cm 3 ), electrical resistivity (μΩm), and flexural strength (MPa) of the electrode members according to the first to third experimental examples were measured. Here, the flexural strength was measured by the three-point flexural strength measurement method.

[0124] Also, the oxidation rate is shown in terms of an exponent, but is shown as the ratio of the oxidation rates of the electrode members according to the second and third experimental examples to the oxidation rate of the electrode member according to the first experimental example.

[0125] Then, a plurality of each of the electrode members according to the first to third experimental examples as described above were prepared, and the density, electrical resistivity, and bending strength were measured for each of the plurality of electrode members, and the oxidation rate was calculated using it as an index. The results are as shown in Table 2.

[0126]

Table 2

[0127] As shown in Table 2, in the first to third experimental examples, the density is at substantially the same level. However, compared with the first experimental example, the oxidation rates of the second and third experimental examples are further slower. That is, while the oxidation rate index of the first experimental example is 1, the oxidation rate index of the second experimental example is 0.5 or more and 0.6 or less, and the oxidation rate index of the third experimental example is more than 0.6 and 0.7 or less. From this, it can be seen that when the composition for an electrode bar according to the embodiment is used, the oxidation rate of the electrode member can be slowed down. That is, it can be seen that the oxidation resistance of the electrode member can be improved.

[0128] Thus, the reason why the oxidation rate of the electrode member according to the second and third experimental examples is further slower than that of the first experimental example is that artificial graphite having better crystallinity than anthracite coal is used as the first carbon-based material. Further, by using a material having better oxidation reactivity than carbon (C) as an oxidation prevention material, the oxidation reaction of carbon (C) is slowed down.

[0129] Comparing the electrical resistivity, the resistivity of the second and third experimental examples is further lower than that of the first experimental example. That is, compared with the first experimental example, the electrical conductivity of the second and third experimental examples is further higher. When the electrical resistivity of the electrode member is small and the electrical conductivity is high, when an arc is generated around the electrode member, the arc can be generated so as to have a uniform distribution. For this reason, when the raw material is melted by the heat of the arc and molten metal is produced, it becomes possible to produce the molten metal in a uniform amount around the electrode bar.

[0130] When comparing the second experimental example with the third experimental example, the electrical resistivity of the second experimental example using natural graphite as the second carbon-based material is even lower than that of the third experimental example. Also, the bending strength of the third experimental example using coke as the second carbon-based material is even higher than that of the second experimental example. From this, it can be understood that when using natural graphite as the second carbon-based material, the electrical resistivity of the electrode member can be further reduced, and when using coke, the strength of the electrode member can be further improved.

[0131] Thus, according to the embodiment of the present invention, the oxidation resistance of the electrode member provided in the electrode rod of the electric furnace can be improved, and thereby, the rate at which the electrode member is oxidized can be reduced. Therefore, the occurrence of penstocks, where the diameter of the electrode member is reduced due to the oxidation reaction, can be suppressed.

[0132] Also, it is possible to suppress a decrease in the area and temperature where heat is generated from the electrode member due to the penstock, or a decrease in the region where an arc occurs around the electrode member. Thereby, when melting the raw material with heat and arc generated from the electrode member to produce molten metal, the operation efficiency can be improved.

[0133] And, by improving the oxidation resistance of the electrode member, the life of the electrode member can be improved. For this reason, the amount of the composition for the electrode rod that is charged into the case to form the electrode member during the operation of the electric furnace can be reduced, and the charging cycle can be lengthened. Therefore, there is an effect that the cost associated with charging the composition for the electrode rod is reduced.

[0134] Also, the electrical resistivity of the electrode member can be reduced. Therefore, the efficiency of generating heat and arc from the electrode rod by the applied power can be increased.

Industrial Applicability

[0135] According to the present invention, the oxidation resistance of the electrode member provided on the electrode rod of the electric furnace can be improved, thereby reducing the rate at which the electrode member is oxidized. Therefore, it is possible to suppress the occurrence of penstocks in which the diameter of the electrode member is reduced due to the oxidation reaction.

Explanation of symbols

[0136] 10a Container 10A First container 10B Second container 100 Main body part 110 Furnace body 110A Outer wall body 110B Inner wall body 111 First discharge port 112 Second discharge port 120 Lid 200, 200a, 200b, 200c Electrode rod 210 Case 230 Power supply member 300 Power supply unit 310 Power supply line 400 Raw material supply unit 410 First hopper 420 Second hopper 430 Feeder 431 First transfer pipe 432 Second transfer pipe 433 Third transfer pipe B Briquette L Molten metal M1 First raw material M2 Second raw material S Slag

Claims

1. A composition for an electrode rod for manufacturing an electrode member of an electric furnace, comprising: a first carbon-based material containing artificial graphite, an antioxidant material containing a material having a higher reactivity with oxygen (O) than carbon (C), and a binder.

2. The composition for an electrode rod according to claim 1, wherein the content of the first carbon-based material in the total weight of the composition for the electrode rod is 50 wt% to 65 wt%, the content of the antioxidant material is 1 wt% to 7 wt%, and the content of the binder is 30 wt% to 43 wt%.

3. The composition for an electrode rod according to claim 1, further comprising a second carbon-based material containing at least one of natural graphite and coke.

4. The composition for an electrode rod according to claim 3, wherein the content of the first carbon-based material in the total weight of the composition for the electrode rod is 50 wt% to 60 wt%, the content of the antioxidant material is 1 wt% to 5 wt%, the content of the binder is 30 wt% to 40 wt%, and the content of the second carbon-based material is 1 wt% to 5 wt%.

5. The composition for an electrode rod according to claim 2 or 4, wherein waste containing artificial graphite is used as the first carbon-based material.

6. The composition for an electrode rod according to claim 2 or 4, wherein the antioxidant material contains at least one of metal Al and metal Si.

7. The first and second carbon-based materials are in a solid state containing a plurality of particles, the antioxidant material is in a liquid state, and the antioxidant material is coated on the surface of the particles of the first carbon-based material. The composition for an electrode rod according to claim 2 or 4.

8. An electrode rod partially inserted into the main body of an electric furnace, comprising: a case having an internal space extending in one direction; a briquette containing a first carbon-based material containing artificial graphite, an antioxidant material containing a material having a higher reactivity with oxygen (O) than carbon (C), and a binder, which is charged into the case and fired to form an electrode member, a part of which is located inside the case and the rest protrudes outside the lower side of the case; and the electrode rod is characterized by including the above.

9. The electrode rod according to claim 8, wherein the antioxidant material contains at least one of metal Al and metal Si.

10. The electrode bar according to claim 8, wherein the briquette contains a second carbon-based material containing at least one of natural graphite and coke.

11. A process of manufacturing a briquette containing a first carbon-based material containing artificial graphite, an antioxidant material having a higher reactivity with oxygen (O) than carbon (C), and a binder, A process of charging the briquette into the inside of a case of an electrode bar fitted in the main body of an electric furnace, A process of firing the briquette using the heat inside the main body and the electric power applied to the case to form an electrode member. A method for manufacturing an electrode bar, comprising the above steps.

12. The process of manufacturing the briquette is A process of mixing the first carbon-based material, the antioxidant material, and the binder to prepare a composition for an electrode bar, A process of granulating the composition for the electrode bar. The method for manufacturing an electrode bar according to claim 11, characterized by including the above steps.

13. The process of manufacturing the briquette is A process of coating the surface of the particles of the first carbon-based material with an antioxidant material, A process of mixing the first carbon-based material coated with the antioxidant material and the binder to prepare a composition for an electrode bar, A process of granulating the composition for the electrode bar. The method for manufacturing an electrode bar according to claim 11, characterized by including the above steps.

14. The process of preparing the composition for the electrode bar is A process of preparing a second carbon-based material containing at least one of natural graphite and coke, A process of mixing the first carbon-based material, the antioxidant material, the binder, and the second carbon-based material. The method for manufacturing an electrode bar according to claim 12, characterized by including the above steps.

15. The process of preparing the composition for the electrode bar is A process of preparing a second carbon-based material containing at least one of natural graphite and coke, A process of mixing the first carbon-based material coated with the antioxidant material, the binder, and the second carbon-based material. The method for manufacturing an electrode bar according to claim 13, characterized by including the above steps.

16. A process of charging raw materials into the inside of the main body of an electric furnace, A process of charging a briquette containing a first carbon-based material containing artificial graphite, an antioxidant material having a higher reactivity with oxygen (O) than carbon (C), and a binder into the inside of a case of an electrode bar fitted so that a part thereof is located inside the main body. A process of firing a briquette inside the case to form an electrode member, a part of which is located inside the case and the rest of which protrudes outside the lower side of the case; A process of supplying power to the electrode bar to generate heat and melt the raw material; A method for producing molten metal, characterized by including the above.

17. The method for producing molten metal according to claim 16, characterized by including a process of reacting an antioxidant material contained in the electrode member with oxygen (O) prior to the reaction of carbon (C) and oxygen (O) contained in the electrode member.

18. The process of reacting the antioxidant material with oxygen (O) The method for producing molten metal according to claim 17, characterized by including a process of reacting at least one of Al and Si contained in the antioxidant material with oxygen (O).

19. The method for producing molten metal according to claim 16, characterized in that the briquette contains a second carbon-based material containing at least one of natural graphite and coke.

20. The method for producing molten metal according to any one of claims 16 to 19, characterized in that the raw material contains hydrogen direct reduced iron reduced by hydrogen.

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