Electrode material for self-baking electrode and manufacturing method thereof

Abstract

Disclosed are an electrode material for a self-baking electrode and a manufacturing method thereof. The method for manufacturing an electrode material for a self-baking electrode according to an embodiment of the present invention, which is a manufacturing method for an electrode material for forming a self-baking electrode, includes: a preparation step of preparing an aggregate mainly composed of carbon; an antioxidant treatment step of coating the surface of the prepared aggregate with an antioxidant; a mixing step of mixing the antioxidant-treated aggregate with binder pitch; and a molding step of molding the mixture of the carbon aggregate and binder pitch into a predetermined shape.

Description

Electrode material for self-igniting electrode and method for manufacturing the same

[0001] The present disclosure relates to an electrode material used in a self-igniting electrode and a method for manufacturing the same.

[0002] Submerged Arc Furnaces (SAF), which are widely used in the production of ferroalloys, produce raw materials by applying electricity to carbon electrodes to generate a large amount of thermal plasma heat.

[0003] And the SAF electrode is formed by inserting electrode material, melting the electrode material, filling it with its own weight, and firing it during use to function as an electrode rod.

[0004] Since these electrodes can self-fire and operate continuously, they can be considered as self-baking continuous electrodes, and the Soderberg type, which is a completely self-baking type with a case made of sheet iron, is a representative example.

[0005] Meanwhile, electrodes, most of which are composed of carbon materials, are continuously oxidized and consumed during electric furnace operation. This oxidation can be further exacerbated by exposure to high temperatures emanating from the surrounding surface, such as with SAF electrodes, and by air entering the furnace from the outside or oxygen contained in the internal reaction gases.

[0006] Oxidation causes the electrode diameter to thin, a phenomenon known as penciling. Thinner electrodes have reduced cross-sectional strength, increasing the risk of breakage. Furthermore, the reduced arc-generating area can reduce the operating efficiency of the electric furnace.

[0007] Therefore, recently, a technology has been used to form an insulating layer on the surface of the electrode to prevent oxidation.

[0008] However, since the insulating layer formed on the electrode surface can act as a factor that impedes the movement of the arc current applied to the electrode surface, it can cause problems in the operation of the arc furnace.

[0009] In addition, in the case of electrodes in which the insulating layer is formed only on the surface, if the insulating layer on the surface is damaged, a problem may arise in which oxidation of the electrode can no longer be prevented.

[0010] One aspect of the present disclosure provides an electrode material for a self-extinguishing electrode and a method for manufacturing the same, which can effectively extend the life of the electrode.

[0011] One aspect of the present disclosure provides an electrode material for a self-extinguishing electrode capable of ensuring stable operation of an electric furnace and a method for manufacturing the same.

[0012] A method for manufacturing an electrode material for a self-extinguishing electrode according to the invention is a method for manufacturing an electrode material for a self-extinguishing electrode for manufacturing an electrode material for forming a self-extinguishing electrode, the method comprising: a preparation step of preparing an aggregate containing carbon as a main component; an anti-oxidation treatment step of coating an anti-oxidation agent on the surface and internal pores of the prepared aggregate; a mixing step of mixing the anti-oxidation-treated aggregate with binder pitch; and a forming step of forming a mixture of the carbon aggregate and the binder pitch into a predetermined shape.

[0013] The above-mentioned anti-oxidation treatment step may include a immersion step of immersing the calcined anthracite forming the aggregate in a sodium silicate aqueous solution; an impregnation step of impregnating the calcined anthracite with the sodium silicate aqueous solution; and a drying step of recovering the calcined anthracite impregnated with the sodium silicate aqueous solution and drying it to remove moisture.

[0014] The above impregnation step may include a depressurization step of depressurizing the sodium silicate aqueous solution in which the calcined anthracite coal is deposited under a depressurized atmosphere below atmospheric pressure; and, after the depressurization step, a pressurization step of pressurizing the sodium silicate aqueous solution in which the calcined anthracite coal is deposited under a pressurized atmosphere above atmospheric pressure.

[0015] In the above-mentioned consideration step, the sodium silicate aqueous solution in which the above-mentioned anthracite coal is deposited can be depressurized in a depressurized atmosphere of 2 to 10 torr for 50 to 70 minutes.

[0016] In the above pressurizing step, the sodium silicate aqueous solution in which the above-mentioned anthracite coal is deposited can be pressurized in a pressurized atmosphere of 9 to 11 bar for 25 to 35 minutes.

[0017] An electrode material for a self-extinguishing electrode according to the invention of the present disclosure can be manufactured by the method for manufacturing the electrode material for a self-extinguishing electrode.

[0018] According to the present disclosure, an electrode material for a self-extinguishing electrode and a method for manufacturing the same can be provided, which can effectively extend the life of the electrode.

[0019] In addition, according to the present disclosure, an electrode material for a self-extinguishing electrode capable of ensuring stable operation of an electric furnace and a method for manufacturing the same can be provided.

[0020] Figure 1 is a process diagram of a method for manufacturing an electrode material for a self-igniting electrode according to an actual embodiment.

[0021] Figure 2 illustrates calcined anthracite and sodium silicate aqueous solution used in a method for manufacturing an electrode material for a self-igniting electrode according to one embodiment.

[0022] Figure 3 is a comparative illustration of the oxidation test results of an electrode material manufactured by a method for manufacturing an electrode material for a self-igniting electrode according to one embodiment and a general electrode material.

[0023] Throughout the specification, the same reference numerals denote the same components. This specification does not describe all elements of the embodiments, and any content that is general in the technical field to which the present invention pertains or that overlaps between the embodiments is omitted. The terms 'part, module, element, block' used in the specification may be implemented in software or hardware, and depending on the embodiments, multiple 'parts, modules, elements, blocks' may be implemented as a single component, or a single 'part, module, element, block' may include multiple components.

[0024] Throughout the specification, when a part is said to be "connected" to another part, this includes not only direct connection but also indirect connection, and indirect connection includes connection via a wireless communication network.

[0025] Additionally, when a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0026] Throughout the specification, when it is said that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where another element exists between the two elements.

[0027] The terms first, second, etc. are used to distinguish one component from another, and the components are not limited by the aforementioned terms.

[0028] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0029] The identification codes in each step are used for convenience of explanation and do not describe the order of each step, and each step may be performed in a different order than specified unless the context clearly indicates a specific order.

[0030] The term “and / or” may include any combination of multiple related described elements or any one of multiple related described elements.

[0031] The operating principle and embodiments of the present invention will be described with reference to the attached drawings below.

[0032] Figure 1 is a process diagram of a method for manufacturing an electrode material for a self-igniting electrode according to one embodiment.

[0033] As illustrated in Fig. 1, a method for manufacturing an electrode material for forming a self-sintering electrode may include a preparation step (s1), an anti-oxidation treatment step (s2), a mixing step (s3), and a molding step (s4).

[0034] In the preparation stage (s1), aggregates containing carbon as the main component can be prepared. The aggregates can be prepared from calcined anthracite coal. Calcined anthracite coal can be prepared by calcining anthracite coal at 2500℃ to remove moisture and volatile matter. Calcined anthracite coal can be prepared by classifying it to have a particle size distribution of 5 to 10 mm. Calcined anthracite coal, calcined to remove moisture and volatile matter, can have improved density and electrical conductivity, and enhanced oxidation resistance. The particle size distribution of calcined anthracite coal can be an important factor in determining the strength of the molded body later on.

[0035] In the anti-oxidation treatment step (s2), an antioxidant can be coated on the surface and internal pores of the aggregate prepared in the preparation step (s1). An electrode material manufactured using such anti-oxidation-treated aggregate maintains a strong coating of antioxidant not only between particles but also within the pores of the particles, thereby preventing oxidation from extending internally from the oxidized surface even when a portion of the surface is oxidized. The process of coating the antioxidant within the pores will be described later.

[0036] Therefore, electrodes manufactured using such electrode materials can prevent or suppress oxidation of the electrode in a high-temperature atmosphere inside an electric furnace, and reduce consumption of the electrode due to oxidation prevention, thereby extending the service life of the self-extinguishing electrode.

[0037] In the mixing step (s3), the oxidation-resistant calcined anthracite can be mixed with binder pitch. In the mixing step (s3), the aggregate and binder pitch can be mixed in a high-temperature atmosphere.

[0038] In the forming step (s4), a mixture of calcined anthracite and binder pitch can be molded into a mold to form a molded body of a certain shape. With the completion of the forming step (s4), the electrode material manufacturing process can be completed.

[0039] The electrode material manufactured in this way can be placed in a case to be used as a self-extinguishing electrode in an electric furnace. The case can be raised and lowered to adjust its position, and the electrode material can be fired due to the heat generated in the electric furnace during operation and its own load in response to the lowering motion of the case, thereby performing the function of an electrode rod. At this time, the binder pitch of the electrode material can be carbonized to form carbon. As described above, the binder pitch is evenly mixed with the aggregate subjected to an oxidation prevention treatment in the mixing step (s3) and evenly distributed on the surface of the electrode material, so that carbon can be evenly distributed on the surface of the electrode during the firing process.

[0040] Therefore, the electrode material can ensure stable operation of the electric furnace by suppressing or preventing oxidation of the electrode through the anti-oxidation treated aggregate while facilitating the movement of arc current through the surface of the electrode.

[0041] The following describes in more detail the anti-oxidation treatment step (s2) of coating the surface and internal pores of the aggregate with an anti-oxidation agent.

[0042] The anti-oxidation treatment step (s2) may include a deposition step (s2-1), an impregnation step (s2-2), and a drying step (s2-3).

[0043] In the deposition step (s2-1), as illustrated in Fig. 2, calcined anthracite coal and a sodium silicate aqueous solution, which form carbon aggregates, are prepared, and the calcined anthracite coal can be deposited in the sodium silicate aqueous solution. Sodium silicate is a sodium salt of silicic acid. Various aqueous solutions can be used as the sodium silicate aqueous solution within the range containing silicic acid.

[0044] In the impregnation step (s2-2), calcined anthracite is impregnated with a sodium silicate aqueous solution, and in the drying step (s2-3), the calcined anthracite impregnated with the sodium silicate aqueous solution can be recovered and dried to remove moisture.

[0045] The impregnation step (s2-2) may include a depressurization step (s2-2-1) in which the sodium silicate aqueous solution in which the calcined anthracite coal is deposited is depressurized under a depressurized atmosphere below atmospheric pressure, and a pressurization step (s2-2-2) in which the sodium silicate aqueous solution in which the calcined anthracite coal is deposited is pressurized under a pressurized atmosphere above atmospheric pressure after the depressurization step (s2-2-1).

[0046] In the depressurization step (s2-2-1), the sodium silicate aqueous solution in which the calcined anthracite is deposited is charged into the chamber of the vacuum impregnation machine, and the vacuum impregnation machine can be operated so that the inside of the chamber forms a depressurized atmosphere close to a vacuum state.

[0047] In such a depressurized atmosphere, the gas present in the pores of the calcined anthracite coal expands and moves outward, providing a space where the pores of the calcined anthracite coal can be impregnated with a sodium silicate solution.

[0048] In the consideration stage, the sodium silicate aqueous solution in which the anthracite coal is deposited can be depressurized for 50 to 70 minutes in a reduced pressure atmosphere of 2 to 10 torr, which is practically close to a vacuum.

[0049] At this time, it may be difficult to achieve a decompression atmosphere below 2 torr. Furthermore, if the decompression atmosphere exceeds 10 torr or the decompression time is less than 50 minutes, sufficient gas mobility within the pores may be difficult to ensure. Furthermore, the decompression time may reach its maximum at around 70 minutes, and if it exceeds 60 minutes, energy waste due to decompression may occur.

[0050] In the pressurization step (s2-2-2), the vacuum impregnation device is operated to form a pressurized atmosphere higher than atmospheric pressure inside the chamber, so that the sodium silicate aqueous solution in which the calcined anthracite is deposited is pressurized in the pressurized atmosphere.

[0051] When a pressurized atmosphere is created in this way, the sodium silicate aqueous solution impregnating liquid is permeated into the pores of the calcined anthracite, which are empty due to the pressure difference, until the pressure becomes constant, and thus the surface and internal pores of the calcined anthracite can be impregnated with the sodium silicate aqueous solution.

[0052] In the pressurization step (s2-2-2), the sodium silicate aqueous solution in which the calcined anthracite is deposited can be pressurized for 25 to 35 minutes in a pressurized atmosphere of 9 to 11 bar.

[0053] If the pressurization pressure falls below 9 bar or the pressurization time falls below 25 minutes, the sodium silicate solution may not completely penetrate the pores of the calcined anthracite. Furthermore, if the pressurization pressure exceeds 11 bar or the pressurization time exceeds 35 minutes, it may be difficult to further increase the impregnation rate, resulting in energy waste due to pressurization.

[0054] And in the drying step (s2-3), the calcined anthracite coal, which has been completely impregnated with the sodium silicate aqueous solution, can be recovered from the sodium silicate aqueous solution and dried to remove moisture from the calcined anthracite coal.

[0055] The drying step (s2-3) is carried out at a temperature of 140 to 160°C for 25 to 35 minutes, so that moisture contained in the calcined anthracite can be quickly removed in a short period of time.

[0056] The conditions of the drying step (s2-3) are not limited to those described above. The drying step (s2-3) may also be carried out through natural drying over several days, as long as the moisture contained in the calcined anthracite is completely removed.

[0057] Hereinafter, the present invention will be described in more detail through examples. However, the description of these examples is intended only to illustrate the implementation of the present invention and is not intended to limit the present invention. This is because the scope of the present invention is determined by the matters set forth in the patent claims and matters reasonably inferred therefrom.

[0058] [Example]

[0059] In the preparation stage (s1), the anthracite coal was calcined at 2500°C to remove moisture and volatile matter, and the calcined anthracite coal was classified to have a particle size distribution of 5 to 10 mm.

[0060] In the immersion step (s2-1) of the oxidation prevention treatment step (s2), 1 kg of the prepared calcined anthracite was immersed in 10 L of sodium silicate aqueous solution. In the depressurization step (s2-2-1) of the impregnation step (s2-2), the sodium silicate aqueous solution in which the calcined anthracite was immersed was allowed to stand for 1 hour in a depressurized atmosphere of 2 to 10 torr, and then in the pressurization step (s2-2-2) of the impregnation step (s2-2), it was pressurized for 30 minutes in a pressurized atmosphere of 10 bar. In the drying step (s2-3), the calcined anthracite impregnated with the sodium silicate aqueous solution was recovered from the sodium silicate aqueous solution and dried at 150°C for 30 minutes.

[0061] After the oxidation prevention treatment step (s2), in the mixing step (s3), the oxidation prevention-treated calcined anthracite is mixed with binder pitch, and the mixture thus mixed is molded using a mold in the molding step (s4).

[0062] Figure 3 shows a comparison of oxidation test results of an electrode material (right) manufactured by a method for manufacturing an electrode material for a self-igniting electrode according to the present embodiment and a general electrode material (left).

[0063] This test examines whether or not both electrode materials are oxidized under conditions identical to the operating environment of a SAF electric furnace.

[0064] As shown in Fig. 3, it can be confirmed that the oxidation consumption (13.5%) of the electrode material according to the present embodiment coated with sodium silicate is significantly less than the oxidation consumption (38.6%) of the general electrode material not coated with sodium silicate.

[0065] Although exemplary embodiments of the present invention have been described above, the present invention is not limited thereto, and those skilled in the art will understand that various changes and modifications are possible within the scope and spirit of the claims set forth below.

Claims

1. A method for manufacturing an electrode material for a self-igniting electrode, which manufactures an electrode material for forming a self-igniting electrode, A preparatory step for preparing aggregates containing carbon as the main component; An anti-oxidation treatment step of coating an anti-oxidation agent on the surface and internal pores of the prepared aggregate; A mixing step of mixing the above-mentioned anti-oxidation treated aggregate with binder pitch; and A method for manufacturing an electrode material for a self-extinguishing electrode, comprising a molding step of molding a mixture of the above carbon aggregate and binder pitch into a certain shape.

2. In paragraph 1, The above anti-oxidation treatment step is, A precipitation step of precipitating the calcined anthracite coal forming the above aggregate in a sodium silicate aqueous solution; An impregnation step of impregnating the above-mentioned anthracite coal with a sodium silicate aqueous solution; and A method for manufacturing an electrode material for a self-igniting electrode, comprising a drying step of recovering the calcined anthracite impregnated with the above sodium silicate aqueous solution and drying it so that moisture is removed.

3. In paragraph 2, The above impregnation step is, A depressurizing step of depressurizing the sodium silicate aqueous solution in which the above-mentioned anthracite coal is deposited under a reduced pressure atmosphere below atmospheric pressure; and A method for manufacturing an electrode material for a self-igniting electrode, comprising: a pressurizing step of pressurizing a sodium silicate aqueous solution in which the calcined anthracite coal is deposited under a pressurized atmosphere higher than atmospheric pressure, after the depressurizing step.

4. In paragraph 3, A method for manufacturing an electrode material for a self-calcining electrode, wherein in the above-mentioned considering step, the sodium silicate aqueous solution in which the calcined anthracite is deposited is decompressed in a reduced pressure atmosphere of 2 to 10 torr for 50 to 70 minutes.

5. In paragraph 3, A method for manufacturing an electrode material for a self-igniting electrode, wherein in the pressurizing step, the sodium silicate aqueous solution in which the calcined anthracite is deposited is pressurized in a pressurized atmosphere of 9 to 11 bar for 25 to 35 minutes.

6. An electrode material for a self-igniting electrode manufactured by a method for manufacturing an electrode material for a self-igniting electrode according to any one of claims 1 to 5.

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