Highly conductive, oxidation-resistant graphite electrode

Abstract

The application relates to the field of carbon materials, and discloses a high-conductivity anti-oxidation graphite electrode. The electrode comprises a graphite framework base body, self-repairing microcapsules and a multi-dimensional conductive reinforcing network. The microcapsules are composed of high-temperature-resistant composite wall materials covering active anti-oxidation core materials; and the conductive network is constructed by carbon nanotubes and graphene in cooperation. The process comprises microcapsule pre-preparation, conductive network pre-dispersion, kneading forming, stage baking and graphitization. The application realizes real-time dynamic plugging of microcracks, improves the anti-oxidation performance and reduces the loss rate, and ensures excellent conductive characteristics and mechanical stability.

Description

Technical Field

[0001] This invention belongs to the field of carbon materials, specifically relating to a highly conductive and antioxidant graphite electrode. Background Technology

[0002] In ultra-high power electric arc furnaces and related hot processing equipment, graphite electrodes need to possess extremely high electrical conductivity to carry megaampere-level currents and maintain structural mechanical stability in extremely high-temperature environments exceeding 2,000 degrees Celsius. Because graphite itself is a crystalline structure composed of carbon elements, it exhibits high chemical reactivity in high-temperature air environments, readily undergoing violent oxidation reactions with oxygen. This can cause electrode surface peeling, cross-sectional shrinkage, and a dramatic increase in current density, potentially leading to premature electrode failure or even breakage, resulting in economic losses for industrial production.

[0003] Traditional anti-oxidation methods commonly used in the industry mainly include surface coating technology and substrate impregnation processes. Surface coating technology typically involves covering the surface of a graphite substrate with a dense insulating layer composed of carbides, silicides, or composite glass enamels, providing protection by cutting off the contact path between oxygen and carbon atoms. Substrate impregnation processes, on the other hand, involve pressing an inorganic salt or phosphate solution of a specific viscosity into the micropores of the graphite electrode, filling the pores at the microscale and forming a thin film to delay the inward penetration of the oxidizing atmosphere.

[0004] In actual service, graphite electrodes are not in an ideal static or uniformly heated state, but are subjected to severe thermal shock, strong electromagnetic vibration, and complex periodic current loads over a long period of time. This dynamic condition can easily cause the originally dense surface coating to develop micro-cracks due to the mismatch of thermal expansion coefficients, and may even cause peeling under mechanical stress.

[0005] Once the physical integrity of the coating is compromised at the microscale, the existing defense system will face irreversible collapse: external oxygen will utilize these micron-sized physical gaps to rapidly erode the graphite matrix, driven by capillary effects and concentration gradients. In this situation, traditional coating technologies, lacking dynamic adjustment capabilities, cannot seal the existing cracks in real time, causing the oxidation reaction to spread rapidly from point to surface into the depths of the electrode, leading to a precipitous drop in the matrix strength. Summary of the Invention

[0006] To address the problems of oxygen infiltration and irreversible oxidation loss in existing graphite electrodes under high temperature, high mechanical stress, and severe thermal shock conditions due to damage to the surface protective layer or microcracks within the substrate, this invention provides a highly conductive and antioxidant graphite electrode. This invention constructs an active-response microcapsule self-healing system within the graphite electrode substrate, combined with a multidimensional conductivity-enhancing network and a hierarchical antioxidant barrier, achieving real-time dynamic sealing of microcracks and in-situ protection of damaged areas. This improves the electrode's antioxidant performance while ensuring excellent conductivity and mechanical stability.

[0007] This invention provides a highly conductive and antioxidant graphite electrode, comprising a graphite framework matrix, a self-healing microcapsule component, and a multidimensional conductive reinforcement network. The graphite framework matrix is ​​formed using high-quality needle coke and petroleum coke as aggregates and medium-temperature coal tar pitch or modified pitch as a binder, through kneading, molding, calcination, and graphitization treatment. The self-healing microcapsule component includes a high-temperature resistant composite wall material and an active antioxidant core material encapsulated within the high-temperature resistant composite wall material.

[0008] In a preferred embodiment of the present invention, the self-healing microcapsule component comprises 3.5% to 8.5% of the total mass of the graphite electrode. The high-temperature resistant composite wall material employs a dense shell structure formed by cross-linking and curing a ceramic precursor polymer. Specifically, the ceramic precursor polymer is one or more of polycarbosilane, polysilazane, or aluminum sol-modified phenolic resin. The wall thickness of the high-temperature resistant composite wall material is controlled between 200 nm and 800 nm to ensure that it does not burst during the high-temperature graphitization stage, while simultaneously enabling brittle fracture to release the active antioxidant core material under stress concentration at the crack tip induced by mechanical stress. The active antioxidant core material is a blend of borate esters and organophosphorus compounds in a mass ratio of 4:1 to 5:1. The borate esters are selected from one or more of tri-n-butyl borate, triisopropyl borate, or cyclic borate esters; the organophosphorus compounds are selected from one or more of triphenyl phosphate, triphenyl phosphite, or resorcinol bisphosphate.

[0009] The self-healing microcapsule components have an average particle size distribution between 10 and 45 micrometers, with a D50 particle size of 25 micrometers ± 2 micrometers. The surface of the microcapsules is modified with a silane coupling agent selected from aminopropyltriethoxysilane or vinyltrimethoxysilane to enhance the interfacial bonding between the microcapsules and the graphite particles and the binder pitch, preventing interfacial delamination due to differences in thermal expansion coefficients during electrode service.

[0010] In a preferred embodiment of the present invention, the multidimensional conductive enhancement network is synergistically constructed from zero-dimensional ultrafine carbon black, one-dimensional multi-walled carbon nanotubes, and two-dimensional graphene microsheets. The total mass percentage of the multidimensional conductive enhancement network in the graphite matrix is ​​1.2% to 2.8%. The multi-walled carbon nanotubes have a diameter of 10 to 30 nanometers and a length of 5 to 15 micrometers, serving to bridge graphite particles and compensate for the localized increase in resistance caused by the introduction of microcapsules. The graphene microsheets have a thickness of 1 to 5 nanometers and a radial dimension of 5 to 20 micrometers, reducing the resistivity of the electrodes in the axial direction through their directional arrangement between graphite layers.

[0011] The present invention also provides a preparation process for the above-mentioned highly conductive and antioxidant graphite electrode, comprising the following steps: Step 1: Pre-fabrication of self-healing microcapsules: The active antioxidant core material is added to deionized water containing a surfactant and subjected to high-speed emulsification at a shear speed of 3000 rpm to 5000 rpm to form a stable water-oil emulsion. A solution of the ceramic precursor polymer is added dropwise to the emulsion, and the pH of the system is adjusted to 3.5 to 4.5 to initiate an in-situ polymerization reaction. The reaction temperature is controlled at 65°C to 85°C, and the reaction time is 4 to 8 hours. After the reaction is complete, the microcapsule is obtained by centrifugation, washing with deionized water until neutral, and drying under vacuum at 45°C to 60°C for 24 hours.

[0012] The second step is raw material pretreatment and batching: needle coke and petroleum coke are crushed and screened according to gradation requirements to obtain aggregates of different particle sizes. The gradation requirements are: 25% to 30% of particles with a diameter of 8 mm to 12 mm, 20% to 25% of particles with a diameter of 4 mm to 8 mm, 15% to 20% of particles with a diameter of 0.5 mm to 4 mm, and the remainder being powder with a diameter less than 0.5 mm. The aggregates are preheated at 150°C to 180°C for 2 hours.

[0013] The third step is the pre-dispersion of the multidimensional conductive network: the multi-walled carbon nanotubes and graphene microsheets are added to part of the binder asphalt and pre-mixed at 200°C to 220°C using a high-shear disperser with a shear speed of 2000 rpm for 1.5 hours to ensure that the conductive filler is unbound and uniformly dispersed in the asphalt matrix.

[0014] Step four, kneading process: The preheated aggregate is fed into a Sigma-type twin-paddle kneader, along with the remaining binder asphalt and the conductive network-containing asphalt obtained in step three. The kneading temperature is set to 165℃ to 185℃. 15 to 20 minutes before the end of kneading, the self-healing microcapsule component obtained in step one is slowly added to the kneader for secondary mixing. During this stage, the stirring speed must be controlled to be less than 35 rpm to avoid excessive shear stress that could cause premature microcapsule breakage.

[0015] Step 5, Molding Process: Cool the kneaded paste to 115℃ to 130℃, then load it into the barrel of the extrusion molding machine. Turn on the vacuum pump to create a vacuum inside the barrel below -0.095MPa, and maintain this vacuum for 10 minutes to remove volatiles and air from the paste. Mold the paste under an extrusion pressure of 20MPa to 35MPa to obtain a green compact.

[0016] Step 6, staged calcination: The green body is embedded in coke powder protective material and calcined in a tunnel kiln or ring furnace. The calcination curve is divided into five stages: The first stage is from room temperature to 350℃, with a heating rate of 2℃ / hour to 5℃ / hour. This stage is the softening period of the binder asphalt and the emission of lightweight components; the second stage is from 350℃ to 550℃, with a heating rate controlled at 1.5℃ / hour to 3℃ / hour. This stage is the pyrolysis and coking period of the asphalt, which is the key period for the formation of the carbon skeleton; the third stage is from 550℃ to 850℃, with a heating rate of 5℃ / hour to 8℃ / hour; the fourth stage is from 850℃ to 1150℃, with a heating rate of 10℃ / hour to 15℃ / hour. In this stage, the microcapsule wall material undergoes a ceramic transformation, forming a high-temperature resistant and hard outer shell; the fifth stage is from 1150℃ to 1300℃, with a holding time of 20 hours to 40 hours.

[0017] Step 7, graphitization treatment: The calcined product is placed in an internally heated graphitization furnace (Acheson furnace) or a series-connected graphitization furnace, and the temperature is raised to 2600℃ to 3000℃ under an argon protective atmosphere or a reducing atmosphere. The high temperature causes the carbon atoms to rearrange to form an ideal graphite crystal structure, while simultaneously achieving deep integration of the conductive reinforcement network with the graphite matrix.

[0018] Step 8, Post-treatment and Impregnation: The graphitized electrode is impregnated under vacuum pressure using modified pitch with a high residual carbon content as the impregnating agent. The impregnation pressure is 1.2 MPa to 1.8 MPa, and the impregnation temperature is 180℃ to 220℃. After impregnation, a second firing is performed to obtain the final product.

[0019] In a preferred embodiment of the present invention, the filling rate of the active antioxidant core material in the self-healing microcapsule component is greater than 85%. During electrode service, when microcracks with a width of 5 to 200 micrometers are generated in a local area due to thermal stress or mechanical impact, the microcapsules on the crack propagation path rupture under the stress field at the crack tip. The borate ester compounds in the core material undergo thermal decomposition at high temperatures (above 450°C) to generate a fluid boron trioxide glassy substance. Driven by capillary force, the glassy substance automatically undergoes physical filling and wetting along the crack pores. Simultaneously, the organophosphorus compounds undergo dehydrogenation under thermal action and chemically crosslink with the oxygen-containing active sites on the graphite surface to generate a stable phosphate or polyphosphate layer. The synergistic effect of boron trioxide and phosphate forms a dense composite protective film with low oxygen permeability in situ on the crack-damaged surface, thereby blocking further diffusion of oxygen into the matrix.

[0020] In a preferred embodiment of the present invention, the multidimensional conductive enhancement network counteracts the contact resistance introduced by the microcapsules as a non-conductive phase by constructing continuous electron transport channels. Graphene microsheets, utilizing their large radial dimensions, form layered overlaps between graphite aggregate particles, while multi-walled carbon nanotubes leverage their high aspect ratio to penetrate the binder coke layer, achieving point-to-point conduction between aggregates. This structure ensures that the resistivity of the finished graphite electrode is less than 5.5 μΩ·m at room temperature, and that the rate of change of resistivity due to temperature rise is reduced at high temperatures above 1000°C.

[0021] The high-temperature resistant composite wall material described in this invention undergoes an in-situ ceramization process under graphitization at high temperatures, transforming microcapsules into ceramic microspheres with microporous structures. These microspheres not only carry antioxidants but also act as dispersed reinforcing phases embedded in the graphite matrix, improving the flexural strength and thermal shock resistance of the graphite electrodes by deflecting crack propagation paths.

[0022] In a preferred embodiment of the present invention, pressure control during the calcination stage in the sixth step is crucial. Within the critical range of 550°C to 850°C, introducing slightly positive pressure nitrogen gas (0.1 MPa to 0.3 MPa) into the calcination environment effectively suppresses premature volatilization of the core material inside the microcapsules before complete physical sealing, ensuring the effective content of the self-healing components in subsequent use.

[0023] In the molding process, the extrusion speed is controlled between 2 mm / s and 5 mm / s. Low-speed extrusion ensures that the microcapsules in the paste will not aggregate or break due to excessive fluid shear force, thereby ensuring the uniform spatial distribution of microcapsules on the green section.

[0024] The highly conductive, oxidation-resistant graphite electrode of this invention achieves a dual protection mechanism of matrix oxidation resistance and crack self-repair through the aforementioned component design and process control. Compared with traditional passive protection technologies that rely on surface coatings, this invention does not depend on the integrity of external physical barriers, but instead achieves real-time damage sensing and active repair through internally dispersed microcapsules. In actual tests in industrial electric arc furnaces, when the surface coating peels off due to thermal shock, the oxidation loss rate of the electrode of this invention is lower than that of ordinary graphite electrodes, and the current carrying capacity is improved.

[0025] In a preferred embodiment of the present invention, the kneading power consumption of the material in the fourth step needs to be monitored in real time. By adjusting the torque of the kneading blades, the plasticity of the paste is ensured to be within the range of 18 mm to 25 mm. This plasticity ensures that a dense interface is formed between the microcapsules, graphite aggregate, and conductive network during the subsequent extrusion molding process, eliminating micropores and improving the density of the electrode.

[0026] The specific physicochemical properties of the finished graphite electrode are as follows: bulk density of 1.72 g / cm³. 3 Up to 1.85 g / cm 3 The ash content is below 0.3%; the elastic modulus is between 8 GPa and 12 GPa. By adjusting the ratio of microcapsules to conductive reinforcement networks, customized production can be carried out according to different furnace power requirements (such as RP, HP, UHP levels), which has strong engineering applicability.

[0027] The organophosphorus compounds introduced into the active antioxidant core material have decomposition products that exhibit reducing properties at high temperatures, thus inhibiting the catalytic oxidation of trace metallic impurities present in the graphite matrix. Boron trioxide, produced by the pyrolysis of borate esters, is molten at high temperatures; its low viscosity and excellent wettability allow the repair film to penetrate deep into nanoscale microcracks, achieving full-scale antioxidant coverage.

[0028] In a preferred embodiment of the present invention, during the preparation of microcapsules in the first step, by controlling the concentration of the emulsifier to be between 0.5% and 1.5%, spherical microcapsules with monodisperse characteristics can be obtained, avoiding stress concentration inside the electrode caused by particle agglomeration. During the conversion of the ceramic precursor polymer into the ceramic wall material, its volume shrinkage rate is compensated by the pre-added nano-silicon carbide powder, ensuring the integrity and airtightness of the wall material structure.

[0029] This invention addresses the industry pain point of graphite electrodes being easily damaged and difficult to repair under extreme operating conditions by introducing a self-healing mechanism inside the graphite electrode. Through the synergistic design of the conductivity enhancement network and the anti-oxidation system, it not only extends the service life of the electrode and reduces steelmaking costs, but also provides environmental benefits by reducing dust emissions generated by electrode oxidation and volatilization.

[0030] The seventh step in the preparation process, graphitization, involves dynamically adjusting the heating curve based on the electrode diameter. For large electrodes with a diameter greater than 600 mm, the heating rate is reduced to 15°C / hour to 25°C / hour, with an added intermediate pause to fully eliminate thermal stress within the large component, prevent premature triggering of the self-healing microcapsules due to excessive thermal gradient, and ensure that the repair energy reserves are released during service.

[0031] The wall material of the self-healing microcapsules forms a ceramic microphase in the later stage of graphitization, which has a hardness much higher than that of the graphite matrix. These diffusely distributed high-hardness microparticles can play a mechanical interlocking role at the electrode screw connection (joint), increasing the anti-loosening performance of the threaded connection and reducing the rate of derailment accidents caused by vibration.

[0032] In a preferred embodiment of the present invention, the impregnation process in step eight can be repeated 1 to 3 times. Each impregnation cycle is followed by a calcination. Through multiple cycles, the dense carbon formed after the modified pitch carbonization fills the minute gaps between the microcapsules and the matrix, resulting in a highly airtight electrode system. In high-temperature oxidation experiments, the electrode of the present invention exhibits an initial oxidation temperature at 800°C that is 150°C to 200°C higher than that of conventional electrodes.

[0033] The highly conductive, oxidation-resistant graphite electrode of this invention can, as needed, have an additional composite coating of silicon carbide and silicate sprayed onto its surface as an initial physical defense barrier. This coating, together with the internal self-healing microcapsule system, forms a cascaded protection mode of external defense and internal control: when the external coating is intact, it prevents oxygen from contacting the substrate; when the external coating fails due to mechanical peeling, the internal microcapsules quickly initiate a self-repair process, forming secondary protection on the damaged surface. This multi-layered defense system ensures that the electrode remains under effective oxidation protection throughout its entire service life, reducing the risk of production interruptions due to downtime for electrode replacement.

[0034] In terms of material selection, the true density of the needle coke needs to reach 2.11 g / cm³. 3 The coefficient of thermal expansion is less than 1.1 × 10⁻⁶ in the range of 100℃ to 600℃. -6 / ℃. This selection of high-quality raw materials provides a stable physical environment for the self-healing system, ensuring coordinated thermomechanical properties. The coking value of the binder bitumen is greater than 54%, ensuring the continuity and strength of the carbon skeleton.

[0035] During the kneading process, the one-dimensional multi-walled carbon nanotubes in the conductive reinforcement network exhibit a certain preferred orientation in the axial direction of the electrode due to the directional shearing action of the blades. This orientation further optimizes the axial conductivity of the electrode, enabling the finished electrode to achieve high current density (greater than 25 A / cm²). 2 When operating under these conditions, the core temperature of the electrode is reduced by 50°C to 80°C compared to conventional electrodes, which reduces the concentration of thermal stress in the central area and reduces the probability of crack formation from the source.

[0036] Compared with the prior art, the beneficial effects of the present invention are: This invention constructs a complete antioxidant system with self-evolution capabilities. The system remains dormant at room temperature, without affecting electrode processing and transport; under high-temperature operating conditions, it is instantly activated upon the occurrence of damage, improving the overall service performance of graphite electrodes in ultra-high power electric arc furnace steelmaking, non-ferrous metal smelting, and other fields, thus possessing industrial application value and economic significance. Detailed Implementation

[0037] This invention provides a highly conductive and antioxidant graphite electrode, whose macroscopic structure comprises a graphite framework matrix with high mechanical strength, self-healing microcapsule components dispersed in the micropores and particles of the graphite framework matrix, and a multidimensional conductive reinforcement network interspersed within the graphite framework matrix. This three-in-one structural design enables the electrode to maintain the excellent processing performance of traditional graphite electrodes while possessing the ability to actively repair microcracks and extremely low resistivity.

[0038] The technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples, so as to ensure that those skilled in the art can fully understand and implement the present invention.

[0039] Example 1: Graphite skeleton matrix (needle coke: petroleum coke = 6:4, aggregate gradation 8-12mm 28%, 4-8mm 22%, 0.5-4mm 18%, <0.5mm 32%; coal tar pitch binder 18%). The self-healing microcapsule component comprises 5.5% (the ceramic precursor polymer is polycarbosilane with a wall thickness of 500 nm; the active antioxidant core material is tributyl borate: triphenyl phosphate = 4:1 with a filling rate of 88%; the microcapsule particle size D50 = 25 μm, modified with aminopropyltriethoxysilane). Multidimensional conductive enhancement network 2.0% (multi-walled carbon nanotubes with a diameter of 20 nm and a length of 10 μm; graphene microsheets with a thickness of 3 nm and a radial dimension of 12 μm; ultrafine carbon black accounting for 0.3%). Preparation steps: S1: Pre-fabrication of self-healing microcapsules, adding active core material to deionized water containing surfactant, emulsifying at high speed of 4000 r / min; adding polycarbosilane solution dropwise, adjusting pH to 4.0, in-situ polymerization at 75℃ for 6 hours, centrifuging and washing, and vacuum drying at 50℃; S2: Raw material pretreatment, aggregate crushing and screening followed by preheating at 165℃ for 2 hours; S3: Conductive network pre-dispersion, multi-walled carbon nanotubes and graphene microsheets with some binder, high shear dispersion at 210℃ and 2000r / min for 1.5 hours to obtain asphalt slurry; S4: Mixing and kneading. Preheat the aggregate and put it into the kneader. Add the remaining binder and asphalt slurry and knead at 175°C. Add the microcapsules 18 minutes before the end of the process and stir again at 30r / min to control the plasticity value of the paste to 22mm. S5: Molding, the paste is cooled to 125℃, held under vacuum of -0.096MPa for 10 minutes, and then extruded at 28MPa at an extrusion speed of 3mm / s; S6: Staged roasting, embedding coke powder: ambient temperature -350℃ (3℃ / h), 350-550℃ (2℃ / h), 550-850℃ (6℃ / h, 0.2MPa nitrogen), 850-1150℃ (12℃ / h), 1150-1300℃ for 30 hours; S7: Graphitization, graphitization at 2800℃ under argon protection; S8: Post-treatment, 1.5MPa vacuum pressure impregnation of modified asphalt, and secondary calcination to obtain the finished product.

[0040] Example 2: 3.5% self-healing microcapsule component, with the remaining components and proportions the same as in Example 1; Preparation steps: Same as in Example 1.

[0041] Example 3: 8.5% of the self-healing microcapsule component, with the remaining components and proportions the same as in Example 1; Preparation steps: Same as in Example 1.

[0042] Example 4: 1.2% multidimensional conductive enhancement network, with the remaining components and proportions the same as in Example 1; Preparation steps: Same as in Example 1.

[0043] Example 5: Multidimensional conductive enhancement network 2.8%, other components and proportions are the same as in Example 1; Preparation steps: Same as in Example 1.

[0044] Example 6: Same as Example 1; Preparation steps: The graphitization stage temperature is 2600℃, and the remaining steps are the same as in Example 1.

[0045] Example 7: Same as Example 1; Preparation steps: The graphitization stage temperature is 3000℃, and the remaining steps are the same as in Example 1.

[0046] Example 8: The active antioxidant core material is a cyclic borate ester: triphenyl phosphite = 5:1, and the other components and proportions are the same as in Example 1; Preparation steps: Same as in Example 1.

[0047] Comparative Example 1: The self-healing microcapsule component was removed, and the remaining components were the same as in Example 1; Preparation steps: The microcapsule pre-preparation and addition steps are omitted, and the remaining process parameters and steps are the same as in Example 1.

[0048] Comparative Example 2: The multidimensional conductive enhancement network was removed, and the remaining components were the same as in Example 1; Preparation steps: The conductive network pre-dispersion step is omitted, and the remaining process parameters and steps are the same as in Example 1.

[0049] Test method: Conductivity test: Measure the resistivity at room temperature and 1000℃, and calculate the rate of change of temperature rise; Antioxidant performance test: The oxidation loss rate was measured after 1000℃ air atmosphere insulation for 100 hours. Self-healing efficiency test: Artificially prefabricated 50μm microcracks were kept at 1000℃ for 24 hours, and the crack sealing rate was measured. Physical performance testing: Determining electrode bulk density and coefficient of thermal expansion; Mechanical property testing: Determine flexural strength and elastic modulus.

[0050] The test data comparisons are shown in Table 1 and Table 2.

[0051] Table 1. Comparison of room temperature resistivity, oxidation loss rate at 1000℃, and microcrack sealing rate

[0052] Table 2 Comparison of Flexural Strength, Density, Coefficient of Thermal Expansion, and Modulus of Elasticity

[0053] Examples 1 to 8 utilize microcapsules to release the core material, forming a composite protective film to seal cracks. A conductive network bridges the graphite particles to compensate for contact resistance, and the two work together to ensure the overall performance of the electrode. Comparative Example 1, lacking microcapsules, exhibits a significantly increased oxidation loss rate, making crack repair impossible; Comparative Example 2, lacking a conductive network, shows increased resistivity.

[0054] When the microcapsule content is 5.5% to 8.5%, the conductive network content is 2.0% to 2.8%, and the graphitization temperature is 2800℃ to 3000℃, the antioxidant properties and conductivity are better. Among them, the microcapsule content directly affects the repair efficiency, the conductive network content determines the electron transport efficiency, and the graphitization temperature controls the crystal order. The three work together to ensure the overall performance of the electrode.

[0055] Compared to Comparative Example 1 without microcapsules, the oxidation loss rate at 1000℃ was reduced by more than 74%, the microcrack sealing rate was increased by more than 217%, and the flexural strength was increased by more than 28%. Compared to Comparative Example 2 without conductive network, the room temperature resistivity was reduced by more than 33%, meeting the high current requirements of ultra-high power electric arc furnaces.

[0056] In summary, this invention achieves simultaneous improvement in conductivity, antioxidant properties, and self-repair efficiency by coupling self-healing microcapsules with a multidimensional conductive network, solving the core pain points of traditional graphite electrodes. It is suitable for scenarios such as ultra-high power metallurgical electric furnaces and has good potential for industrialization.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high conductive anti-oxidation graphite electrode, characterized in that, The graphite electrode includes: Graphite framework matrix; Self-healing microcapsule components; Multidimensional conductive enhancement network.

2. The high conductive and oxidation resistant graphite electrode according to claim 1, wherein The graphite skeleton matrix uses needle coke and petroleum coke as aggregates and coal tar pitch or modified pitch as binders, and is formed into a continuous carbon skeleton structure through kneading, molding, calcination and graphitization treatment.

3. The high conductive and oxidation resistant graphite electrode according to claim 1, wherein The self-healing microcapsule components are diffusely distributed in the micropores and between particles of the graphite matrix, and their mass percentage is 3.5% to 8.5% of the total mass of the graphite electrode.

4. The high conductive and oxidation resistant graphite electrode according to claim 1, wherein The self-healing microcapsule component comprises a high-temperature resistant composite wall material and an active antioxidant core material encapsulated within the high-temperature resistant composite wall material.

5. The high conductive and oxidation resistant graphite electrode according to claim 1, wherein The multidimensional conductive enhancement network is interspersed in the graphite matrix and is constructed by the synergistic formation of zero-dimensional ultrafine carbon black, one-dimensional multi-walled carbon nanotubes, and two-dimensional graphene microsheets. The total mass percentage of the multidimensional conductive enhancement network in the graphite electrode is 1.2% to 2.8%.

6. The high conductive and non-oxidizable graphite electrode according to claim 4, wherein The high-temperature resistant composite wall material adopts a dense shell structure formed by cross-linking and curing of ceramic precursor polymers. The ceramic precursor polymers are selected from one or more of polycarbosilane, polysilazane, and aluminum sol-modified phenolic resins.

7. The highly conductive and antioxidant graphite electrode according to claim 4, characterized in that, The active antioxidant core material is a blend of borate ester compounds and organophosphorus compounds in a mass ratio of 4:1 to 5:

1.

8. A highly conductive and antioxidant graphite electrode according to claim 7, characterized in that, The borate ester compound is selected from one or more of tri-n-butyl borate, triisopropyl borate, or cyclic borate esters; the organophosphorus compound is selected from one or more of triphenyl phosphate, triphenyl phosphite, or resorcinol bisphosphate; and the active antioxidant core material has a filling rate of more than 85% in the self-healing microcapsule component.

9. A highly conductive and antioxidant graphite electrode according to claim 1, characterized in that, The surface of the self-healing microcapsule component is modified with a silane coupling agent selected from aminopropyltriethoxysilane or vinyltrimethoxysilane.

10. A highly conductive and antioxidant graphite electrode according to claim 5, characterized in that, In the multidimensional conductive enhancement network, the multi-walled carbon nanotubes are used to bridge graphite particles in the graphite framework matrix and compensate for local contact resistance.

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