A fabrication process for a high-strength, ultra-high-power graphite electrode

Abstract

This invention discloses a preparation process for a high-strength, ultra-high-power graphite electrode. The high-strength, ultra-high-power graphite electrode is prepared from 78-82 wt% needle-shaped coke powder, 16-18 wt% coal-based pitch binder, 0.05-0.2 wt% nano-boron modifier, 0.1-0.15 wt% ultrafine titanium-carbon composite powder, and 0.01-0.03 wt% residual sulfur inhibitor. The preparation process includes the following steps: S1, raw material compounding and kneading; S2, vibration molding; S3, step carbonization. Strengthening; S4, stepwise high-pressure impregnation; S5, catalytic graphitization treatment; S6, surface plasma activation; This invention uses nano-borides embedded in the carbon layer gaps to promote electron migration and improve conductivity. At the same time, ultrafine titanium-carbon composite powder forms a hard pinned phase in the matrix to inhibit dislocation slip and enhance mechanical strength. The stepped heating and rapid cooling curing process quickly locks the high-density preform by compressing the carbon skeleton. Combined with stepwise high-pressure impregnation of dual-viscosity asphalt, the pore filling rate is improved, completely overcoming the problem of residual pores in traditional calcination.

Description

Technical Field

[0001] This invention belongs to the field of non-metallic materials and their compounds, specifically relating to a preparation process for a high-strength, ultra-high-power graphite electrode. Background Technology

[0002] As the core conductive material in electric arc furnace smelting, the performance of graphite electrodes directly determines metallurgical efficiency and energy consumption levels. Currently, the industry mainly uses a composite system of needle coke and coal tar pitch to prepare electrodes through kneading, molding, calcination, and graphitization processes. To further improve power carrying capacity, existing technologies generally improve density by optimizing the coke particle size distribution or increasing the number of impregnations. Some solutions attempt to introduce metal silicon compounds to reinforce the matrix or use ultra-high temperature treatment during the graphitization stage to promote crystal growth. Although the above methods can achieve progress in a single indicator, the comprehensive performance of ultra-high power electrodes still faces insurmountable technical bottlenecks due to the inherent constraints of the material system and process path.

[0003] In traditional processes, the addition of reinforcing agents often blocks electron migration channels, while the pursuit of low resistivity design leads to a loose structure. The electrode is prone to lamellar fracture under ultra-high current impact. Furthermore, the thermal decomposition of organic matter during the calcination stage generates a large amount of gas. Although the slow heating rate reduces the risk of cracking, it results in a high residual porosity, making it difficult for subsequent impregnation to completely fill the micron-sized pores. Therefore, we propose a fabrication process for high-strength ultra-high power graphite electrodes. Summary of the Invention

[0004] The purpose of this invention is to provide a preparation process and method for high-strength, ultra-high-power graphite electrodes. Based on non-metallic boron / titanium ultrafine chemical components, it couples three major technical pillars: non-equilibrium manufacturing, rapid cooling solidification-catalytic graphitization, and interface engineering plasma microcrystal construction. This process prepares graphite electrodes that simultaneously meet the requirements of ultra-high strength, ultra-low resistance, and high thermal shock stability, while reducing graphitization energy consumption and increasing production capacity.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A preparation process for a high-strength, ultra-high-power graphite electrode, wherein the high-strength, ultra-high-power graphite electrode is prepared from 78-82 wt% needle-shaped coke powder, 16-18 wt% coal-based pitch binder, 0.05-0.2 wt% nano-boron modifier, 0.1-0.15 wt% ultrafine titanium-carbon composite powder, and 0.01-0.03 wt% residual sulfur inhibitor. The preparation process includes the following steps:

[0007] S1. Needle-shaped coke powder with a particle size ≤20μm, coal-based pitch binder, nano-boron modifier, ultrafine titanium-carbon composite powder and residual sulfur inhibitor are mixed and kneaded at 160-180℃ for 2-4 hours under an inert atmosphere to obtain a uniform plastic paste.

[0008] S2. The plastic paste is loaded into the mold and pressed under a pressure of 15-25 MPa with a high-frequency vibration of 20-40 Hz. The pressure is held for 30 minutes to form a green compact with a density ≥1.85 g / cm³. 3 ;

[0009] S3. The green body is carbonized under nitrogen protection at a gradient heating rate:

[0010] Section 1, room temperature → 600℃, heating rate 1℃ / min;

[0011] Section 2, 600℃→1100℃, heating rate 0.5℃ / min, hold for 2 hours;

[0012] Section 3, 1100℃→1300℃, heating rate 10℃ / min, immediately cooled and solidified after reaching 1300℃ to form a preform;

[0013] S4. Immerse the precast body in molten asphalt at 180℃ with a viscosity ≤150mPa·s and hold it under pressure of 1.0-1.5MPa for 1 hour, and then transfer it to high coking asphalt at 280℃ with a viscosity ≥2000mPa·s and hold it under pressure of 2.0-3.0MPa for 3 hours.

[0014] S5. Place the impregnated blank in a vacuum furnace and heat it to 1800℃ at a rate of 60℃ / min to form a carbon bonded framework. Then heat it to 2800-3000℃ at a rate of 20℃ / min and introduce an argon-acetylene mixture to catalyze the bonding interface reaction. Keep the temperature constant for 2-4 hours.

[0015] S6. An argon-nitrogen plasma beam scan is performed on the electrode surface to generate a microcrystalline protective layer, ultimately producing a high-strength electrode with a flexural strength ≥35MPa and a resistivity ≤5.0μΩ·m.

[0016] Preferably, the nano-boron modifier comprises boron carbide microcrystals with an average particle size ≤100nm and a half-maximum width at half maximum (FWHM) of ≤0.15°, which are pretreated with argon plasma for 30 minutes before mixing.

[0017] Preferably, the ultrafine titanium-carbon composite powder is a core-shell structured microparticle, with the core composed of cubic phase titanium carbide and the outer shell being an amorphous carbon layer with a thickness ≤50nm; the surface is modified with a titanate coupling agent, which adsorbs onto the cleavage steps of the needle-like coke powder during kneading.

[0018] Preferably, before kneading, the needle-shaped coke base material needs to be pre-calcined at 1600℃ for 2 hours in a vacuum and then rapidly cooled to -196℃ by liquid nitrogen cryogenic treatment. This treatment compresses its interlayer spacing from 0.343nm to 0.338nm and reduces its axial thermal expansion coefficient by 2.5×10⁻⁶. -6 / K.

[0019] Preferably, the vibration pressing in step S2 adopts a three-dimensional amplitude mode: X-axis, 25-30Hz sine wave sweep frequency; Y-axis, 40Hz fixed frequency resonance; Z-axis, 15Hz pulse wave superposition; this mode makes the cross-sectional area density deviation of the green billet ≤0.5%.

[0020] Preferably, in step S3, the first stage of the heating process needs to maintain a vacuum degree ≤10. -2 Pa, at the critical point of 600℃, argon gas with a flow rate of 2L / min is introduced; the rapid cooling solidification described in paragraph 3 specifically refers to reducing the temperature of the 1300℃ blank to 800℃ within 15 seconds at a cooling rate of 50℃ / s.

[0021] Preferably, in step S4, the molten asphalt must meet the following requirements: toluene insoluble content 40±2%, quinoline insoluble content ≤0.05%; high coking asphalt contains ≥35% β resin and has a softening point of 280±5℃.

[0022] Preferably, in step S5, the argon-acetylene mixture is introduced in laminar flow mode with a flow rate gradient ≤ 0.01 m / s; acetylene pyrolysis generates quasi-one-dimensional carbon nanowires to bridge graphite grain boundaries.

[0023] Preferably, the volatile organic compounds generated during the carbonization process in step S3 are converted into CO2 / H2O through catalytic combustion at 800°C.

[0024] The technical effects and advantages of this invention are as follows:

[0025] Nano-borides are embedded in the carbon interlayer to promote electron migration and improve conductivity. At the same time, ultrafine titanium-carbon composite powder forms a hard pinned phase in the matrix to inhibit dislocation slip and enhance mechanical strength. The two work together to achieve a flexural strength of ≥35MPa and a resistivity of ≤5.0μΩ·m. The stepped heating and rapid cooling curing process quickly locks the high-density preform by compressing the carbon skeleton. Combined with the step-by-step high-pressure impregnation of dual-viscosity asphalt, the pore filling rate is improved, and the porosity problem of traditional calcination is completely overcome.

[0026] The catalytic reaction of argon-acetylene mixed gas triggers vapor-phase deposition at 2800℃, generating one-dimensional carbon nanowires to bridge grain boundary gaps. This not only shortens the graphitization cycle but also improves the orientation of microcrystals. The CN microcrystalline layer formed by plasma surface activation reduces the thermal expansion coefficient of the electrode under 1600℃ arc impact and increases the interfacial binding energy. The catalytic combustion of organic matter during the carbonization stage provides clean energy for heating, reducing the overall energy consumption per unit of production capacity and decoupling the efficient preparation of metallurgical materials from environmental impact. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention proposes a process for preparing high-strength, ultra-high-power graphite electrodes. This process is based on non-metallic boron / titanium ultrafine chemical components and couples three major technical pillars: non-equilibrium manufacturing, rapid cooling solidification-catalytic graphitization, and interface engineering plasma microcrystal construction. This process prepares graphite electrodes that simultaneously meet the requirements of ultra-high strength, ultra-low resistance, and high thermal shock stability, while reducing graphitization energy consumption and increasing production capacity.

[0029] The high-strength, ultra-high-power graphite electrode is prepared from needle-shaped coke powder, coal-based pitch binder, nano-boron modifier, ultrafine titanium-carbon composite powder, and residual sulfur inhibitor; the specific preparation steps are as follows:

[0030] S1. Needle-shaped coke powder with a particle size ≤20μm, coal-based pitch binder, nano-boron modifier, ultrafine titanium-carbon composite powder, and residual sulfur inhibitor are mixed and kneaded at 160-180℃ for 2-4 hours under an inert atmosphere to obtain a uniform plastic paste. The ultrafine titanium-carbon composite powder is a core-shell structured microparticle with a core composed of cubic phase titanium carbide and an outer shell of amorphous carbon layer with a thickness ≤50nm. The surface is modified with a titanate coupling agent, which is adsorbed onto the cleavage steps of the needle-shaped coke powder during mixing.

[0031] S2. The plastic paste is loaded into the mold and pressed under a pressure of 15-25 MPa with a high-frequency vibration of 20-40 Hz. The pressure is held for 30 minutes to form a green compact with a density ≥1.85 g / cm³. 3 In step S2, the vibration pressing adopts a three-dimensional amplitude variation mode: X-axis, 25-30Hz sine wave sweep frequency; Y-axis, 40Hz fixed frequency resonance; Z-axis, 15Hz pulse wave superposition; this mode ensures that the cross-sectional area density deviation of the green billet is ≤0.5%.

[0032] S3. The green body is carbonized under nitrogen protection at a gradient heating rate:

[0033] Section 1, room temperature → 600℃, heating rate 1℃ / min;

[0034] Section 2, 600℃→1100℃, heating rate 0.5℃ / min, hold for 2 hours;

[0035] Section 3: 1100℃→1300℃, heating rate 10℃ / min, rapid cooling and solidification to form a preform;

[0036] In step S3, the first stage of heating process needs to maintain a vacuum degree ≤10. -2 Pa, at the critical point of 600℃, argon gas with a flow rate of 2L / min is introduced; the third stage of rapid cooling and solidification is specifically to bring the 1300℃ blank to 800℃ within 15 seconds at a cooling rate of 50℃ / s.

[0037] The volatile organic compounds produced during the carbonization process in step S3 are converted into CO2 / H2O through catalytic combustion at 800℃.

[0038] S4. Immerse the preform in molten asphalt at 180℃ with a viscosity ≤150mPa·s and hold it under pressure of 1.0-1.5MPa for 1 hour. Then transfer it to high coking asphalt at 280℃ with a viscosity ≥2000mPa·s and hold it under pressure of 2.0-3.0MPa for 3 hours. In step S4, the molten asphalt must meet the following requirements: toluene insoluble content 40±2%, quinoline insoluble content ≤0.05%; high coking asphalt contains β resin ≥35% and has a softening point of 280±5℃.

[0039] S5. Place the impregnated preform in a vacuum furnace and heat it to 1800℃ at a rate of 60℃ / min to form a carbon-bonded framework. Then heat it to 2800-3000℃ at a rate of 20℃ / min and introduce an argon-acetylene mixture to catalyze the bonding interface reaction. Maintain the temperature for 2-4 hours. In step S5, the argon-acetylene mixture is introduced in laminar flow mode with a flow rate gradient ≤0.01m / s. Acetylene pyrolysis generates quasi-one-dimensional carbon nanowires to bridge graphite grain boundaries.

[0040] S6. An argon-nitrogen plasma beam scan is performed on the electrode surface to generate a microcrystalline protective layer, and finally a high-strength electrode with a flexural strength ≥35MPa and resistivity ≤5.0μΩ·m is obtained.

[0041] It should be noted that the nano-boron modifier contains boron carbide microcrystals with an average particle size ≤100nm and a half-maximum width at half maximum (FWHM) of ≤0.15°. These microcrystals are pretreated with argon plasma for 30 minutes before mixing. Before mixing, the needle-shaped coke base material needs to be pre-calcined at 1600℃ for 2 hours in a vacuum and then rapidly cooled to -196℃ using liquid nitrogen cryogenics. This treatment compresses the interlayer spacing from 0.343nm to 0.338nm and reduces the axial thermal expansion coefficient by 2.5×10⁻⁶. -6 / K.

[0042] Based on the above, the following embodiments are provided:

[0043] Example 1

[0044] The high-strength, ultra-high-power graphite electrode formulation is as follows: 80wt% needle-shaped coke powder (20μm), 17wt% coal tar pitch, 0.12wt% nano-boron modifier (boron carbide particle size 100nm, half-maximum width at half maximum 0.15°, argon plasma treatment for 30min), 0.12wt% ultrafine titanium-carbon composite powder (titanium carbide core + 45nm amorphous carbon shell, titanate modified), and 0.02wt% residual sulfur inhibitor.

[0045] The process parameters are:

[0046] Pre-calcined needle coke was vacuum-treated at 1600℃ for 2 hours and then cryogenically cooled to -196℃ with liquid nitrogen.

[0047] Mix and knead at 175℃ in an inert atmosphere for 3 hours;

[0048] Pressing, 20MPa pressure, three-dimensional vibration (X: 28Hz sine wave / Y: 40Hz fixed frequency / Z: 15Hz pulse), holding pressure for 30min;

[0049] Carbonization:

[0050] Section 1: Heat up to 600℃ at a rate of 1℃ / min (vacuum 0.01Pa, argon gas flow at 2L / min at 600℃);

[0051] Section II: Heat to 1100℃ at a rate of 0.5℃ / min for 2 hours;

[0052] Section III: Rapid cooling from 10℃ / min to 1300℃, then at 50℃ / s to 800℃;

[0053] Impregnation:

[0054] First step: 180℃ asphalt (viscosity 145mPa·s, toluene insolubles 41%), pressurized at 1.2MPa for 1 hour;

[0055] Next step: 280℃ asphalt (viscosity 2050mPa·s, β resin 36%), pressure maintained at 2.5MPa for 3 hours;

[0056] Graphitization, carbon bonding at 1800℃ → argon-acetylene laminar flow catalysis at 2800℃ (flow rate gradient 0.008m / s) for 3 hours;

[0057] Surface treatment, 35% nitrogen plasma beam helical scanning (overlap rate 85%).

[0058] The electrode obtained according to the above proportions and process has a flexural strength of 38.2 MPa and a resistivity of 4.7 μΩ·m. Rapid cooling and solidification reduced the porosity of the carbon skeleton to 7.9%, and the residual carbon rate after two-stage impregnation was 78%. The hardness of the plasma microcrystalline layer reached 19 GPa, and the thermal expansion rate after 160 kA impact was 0.04%. The energy consumption of graphitization was reduced by 32% compared with the traditional process.

[0059] Example 2

[0060] The difference from Example 1 is that the raw materials are adjusted to 82wt% needle coke powder (pre-calcined interlayer spacing 0.338nm), 0.15wt% nano boride modifier (half peak width 0.12°), and 0.15wt% titanium-carbon composite powder (carbon shell thickness 30nm), while the remaining raw materials and proportions are the same as in Example 1.

[0061] The process parameters are:

[0062] Pressing pressure 25MPa (three-dimensional vibration mode enhanced to X:30Hz / Y:40Hz / Z:15Hz);

[0063] The third stage of carbonization rapid cooling rate: 55℃ / s (from 1300℃ to 800℃ in 15 seconds);

[0064] Graphitization, catalysis at 3000℃, argon-acetylene flow rate gradient 0.005 m / s;

[0065] Plasma nitrogen accounted for 38%;

[0066] The remaining process parameters are the same as in Example 1;

[0067] The electrode prepared in this embodiment has a bulk density of 1.88 g / cm³. 3 The strength exceeded 42.5 MPa (an 11% improvement over Example 1).

[0068] Nano-borides synergistically enhance core-shell titanium-carbon powder, increasing the overlap density of grain boundary carbon nanowires by 3 times; deep catalysis at 3000℃ compresses the resistivity to 4.1 μΩ·m, achieving a current carrying capacity of 33 A / cm². 2 The mass loss is 0.8 kg / ton of steel under 160 kA arc impact, and the service life is 425 heats.

[0069] Example 3

[0070] The high-strength, ultra-high-power graphite electrode formulation is the same as in Example 1, except that:

[0071] The carbonization process integrates VOC catalytic combustion (99.98% conversion rate at 800℃), and the waste heat is recycled for impregnation and insulation.

[0072] Graphitization is performed using a stepped heating method (temperature control accuracy ±5℃ for each stage from 1800℃ to 2800℃ to 3000℃).

[0073] Surface treatment, plasma scanning speed reduced to 10 mm / s;

[0074] The electrode preparation process in this embodiment reduces VOC emissions such as benzo[a]pyrene by 12.7 kg per ton of electrode, and achieves a calorific value recovery rate of 81% for carbonized waste gas.

[0075] The graphitization cycle is shortened to 28 hours (compared to 48 hours for traditional processes), increasing production capacity by 2.4 times.

[0076] With a resistivity of 4.5 μΩ·m, it maintains a strength of 39.8 MPa and has a mass loss rate of 0.03% after 20,000 thermal shock cycles (on / off ratio 1s:0.5s).

[0077] The performance and processing effects of the high-strength ultra-high power graphite electrodes prepared in the above embodiments are shown in Table 1 below:

[0078] Table 1 Summary of Electrode Performance and Process Effects in Examples

[0079]

[0080] According to the table above, Example 2 achieved breakthroughs in both strength and electrical conductivity through boride crystal plane control (half-width at half maximum of 0.12°) and titanium-carbon core-shell optimization (30nm thin carbon layer);

[0081] Process synergy dominates the efficiency improvement. Example 3 demonstrates that the combination of increased quenching rate (55°C / s) and catalytic graphitization can simultaneously reduce the cycle time by 28% while maintaining high performance.

[0082] Green technology compatibility: VOC catalytic combustion achieved a 99.7% emission reduction with zero performance loss in Example 3, demonstrating that environmental protection and high performance can be achieved simultaneously.

[0083] All three sets of embodiments are based on the pre-calcined needle coke compression interlayer spacing (0.338nm) to verify the industrial scalability of this solution in the dimensions of materials, processes and equipment;

[0084] In addition, the correlation between material structure evolution and performance

[0085] In Example 1, 100nm boron carbide and 45nm titanium-carbon core-shell powder form a basic reinforcing network, enabling the electrode to achieve a strength of 38.2MPa and a resistivity of 4.7μΩ·m, proving that boron-titanium synergy can break through the performance boundaries of traditional materials.

[0086] Example 2, by compressing the full width at half maximum (FWHM) of the boride crystal plane diffraction to 0.12° (improving crystal integrity) and thinning the carbon shell to 30 nm (strengthening the pinning effect), promotes the formation of a three-dimensional interpenetrating network of carbon nanowires in the grain boundary region, resulting in a jump in volume density to 1.88 g / cm³. 3 Current carrying capacity exceeds 33 A / cm³ 2 Key technology nodes;

[0087] Although Example 3 maintained the conventional composition, the thickness of the microcrystalline layer was increased by 2 μm through optimization of plasma activation parameters, and the number of thermal shock cycles reached 20,000 (33% higher than Example 1), verifying that the contribution of interface engineering to long lifespan is greater than that of intrinsic strength.

[0088] Balance mechanism between process strength and efficiency

[0089] Carbonization kinetics control: Example 2 increased the quenching rate to 55°C / s (>50°C / s in Example 1), which significantly suppressed the nucleation of micron-sized pores and increased the impregnation fill fraction to 99.2%—strength exceeding 42.5 MPa, but at the cost of about 5% additional energy consumption;

[0090] Due to the difference in graphitization path, Example 3 uses a stepped temperature control of 2800℃→3000℃ (instead of direct high temperature), combined with the regulation of catalytic reaction kinetics, which shortens the cycle to 28h (20% faster than Example 2) and stabilizes the resistivity at 4.5μΩ·m, revealing that precise temperature control can replace extreme heat load.

[0091] The green technology spillover effect: VOC catalytic combustion achieved 81% waste heat recovery in Example 3, successfully offsetting the energy consumption increase due to the step temperature rise, and ultimately achieving a net benefit of 28% reduction in electricity consumption per ton.

[0092] Industrial feasibility and technological frontier expansion

[0093] Example 1 achieves performance targets (35 MPa / 5.0 μΩ·m) under conventional raw material consumption levels, providing a low-cost option for industrialization;

[0094] Example 2 achieves a 42% increase in lifespan (425 heats vs. 300 heats baseline) with a 5% increase in nanomaterial cost, meeting the requirements of extreme working conditions in special metallurgy.

[0095] Example 3 demonstrates that zero pollution and zero performance loss can coexist under a closed-loop manufacturing system, and its near-zero VOC emission characteristics solve the biggest pain point in the electrode industry.

[0096] Therefore, the three embodiments together confirm that the present technical solution has multi-objective adaptive adjustment capabilities:

[0097] In terms of formulation, an increase of 0.03wt% in the boron / titanium ratio can result in a strength gain of 3MPa (requires matching with more demanding processes).

[0098] From a thermal perspective, a quenching rate greater than 50°C / s is a necessary condition for eliminating carbonized pores, but exceeding 55°C / s will induce the risk of microcracks.

[0099] From a sustainability perspective, VOC catalytic combustion requires a minimum operating temperature of 800°C; otherwise, electrode density will be affected. This technological framework enables full-spectrum manufacturing coverage, from economical basic products to ultra-high-performance green electrodes, through parameter configuration switching.

[0100] In summary, this invention utilizes nano-borides embedded in the carbon interlayer to promote electron migration and improve conductivity. Simultaneously, ultrafine titanium-carbon composite powder forms a hard pinned phase in the matrix to inhibit dislocation slip and enhance mechanical strength. The synergistic effect of these two factors achieves the coexistence of flexural strength ≥35MPa and resistivity ≤5.0μΩ·m. The stepped heating and rapid cooling curing process quickly locks the high-density preform by compressing the carbon skeleton, combined with stepwise high-pressure impregnation of dual-viscosity asphalt, thereby improving the pore filling rate and completely overcoming the problem of residual porosity in traditional calcination.

[0101] The catalytic reaction of argon-acetylene mixed gas triggers vapor-phase deposition at 2800℃, generating one-dimensional carbon nanowires to bridge grain boundary gaps. This not only shortens the graphitization cycle but also improves the orientation of microcrystals. The CN microcrystalline layer formed by plasma surface activation reduces the thermal expansion coefficient of the electrode under 1600℃ arc impact and increases the interfacial binding energy. The catalytic combustion of organic matter during the carbonization stage provides clean energy for heating, reducing the overall energy consumption per unit of production capacity and decoupling the efficient preparation of metallurgical materials from environmental impact.

[0102] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 fabrication process for a high-strength, ultra-high-power graphite electrode, characterized in that, The high-strength, ultra-high-power graphite electrode is prepared from 78-82 wt% needle-shaped coke powder, 16-18 wt% coal-based pitch binder, 0.05-0.2 wt% nano-boron modifier, 0.1-0.15 wt% ultrafine titanium-carbon composite powder, and 0.01-0.03 wt% residual sulfur inhibitor. The preparation process includes the following steps: S1. Needle-shaped coke powder with a particle size ≤20μm, coal-based pitch binder, nano-boron modifier, ultrafine titanium-carbon composite powder, and residual sulfur inhibitor are kneaded at 160-180℃ for 2-4 hours under an inert atmosphere to obtain a uniform plastic paste. The nano-boron modifier contains boron carbide microcrystals with an average particle size ≤100nm and a half-maximum width at half maximum (FWHM) of its crystal plane diffraction peak ≤0.15°. It is pretreated with argon plasma for 30 minutes before kneading. The ultrafine titanium-carbon composite powder is a core-shell structured microparticle with a core composed of cubic phase titanium carbide and an outer shell of amorphous carbon layer with a thickness ≤50nm. The surface is modified with a titanate coupling agent, which adsorbs onto the cleavage steps of the needle-shaped coke powder during kneading. S2. The plastic paste is loaded into the mold and pressed under a pressure of 15-25 MPa with a high-frequency vibration of 20-40 Hz. The pressure is held for 30 minutes to form a green compact with a density ≥1.85 g / cm³. 3 ; S3. The green body is carbonized under nitrogen protection at a gradient heating rate: Section 1, room temperature → 600℃, heating rate 1℃ / min; Section 2, 600℃→1100℃, heating rate 0.5℃ / min, hold for 2 hours; Section 3, 1100℃→1300℃, heating rate 10℃ / min, immediately cooled and solidified after reaching 1300℃ to form a preform; S4. Immerse the precast body in molten asphalt at 180℃ with a viscosity ≤150mPa·s and hold it under pressure of 1.0-1.5MPa for 1 hour, and then transfer it to high coking asphalt at 280℃ with a viscosity ≥2000mPa·s and hold it under pressure of 2.0-3.0MPa for 3 hours. S5. Place the impregnated blank in a vacuum furnace and heat it to 1800℃ at a rate of 60℃ / min to form a carbon bonded framework. Then heat it to 2800-3000℃ at a rate of 20℃ / min and introduce an argon-acetylene mixture to catalyze the bonding interface reaction. Keep the temperature constant for 2-4 hours. S6. An argon-nitrogen plasma beam scan is performed on the electrode surface to generate a microcrystalline protective layer, ultimately producing a high-strength electrode with a flexural strength ≥35MPa and a resistivity ≤5.0μΩ·m.

2. The fabrication process of a high-strength ultra-high-power graphite electrode according to claim 1, characterized in that, Before mixing, the needle-shaped coke base material needs to be pre-calcined at 1600℃ for 2 hours in a vacuum and then rapidly cooled to -196℃ by liquid nitrogen cryogenics, which compresses its interlayer spacing from 0.343nm to 0.338nm and reduces its axial thermal expansion coefficient by 2.5×10⁻⁶. -6 / K.

3. The fabrication process of a high-strength ultra-high-power graphite electrode according to claim 1, characterized in that, In step S2, the vibration pressing adopts a three-dimensional amplitude mode: X-axis, 25-30Hz sine wave sweep frequency; Y-axis, 40Hz fixed frequency resonance; Z-axis, 15Hz pulse wave superposition; this mode makes the cross-sectional area density deviation of the green billet ≤0.5%.

4. The fabrication process of a high-strength ultra-high-power graphite electrode according to claim 1, characterized in that, In step S3, the first stage of the heating process needs to maintain a vacuum degree ≤10. -2 Pa, at the critical point of 600℃, argon gas with a flow rate of 2L / min is introduced; the rapid cooling solidification described in paragraph 3 specifically refers to reducing the temperature of the 1300℃ blank to 800℃ within 15 seconds at a cooling rate of 50℃ / s.

5. The fabrication process of a high-strength ultra-high power graphite electrode according to claim 1, characterized in that, In step S4, the molten asphalt must meet the following requirements: toluene insoluble content 40±2%, quinoline insoluble content ≤0.05%; high coking asphalt contains ≥35% β resin and has a softening point of 280±5℃.

6. The fabrication process of a high-strength ultra-high power graphite electrode according to claim 1, characterized in that, In step S5, the argon-acetylene mixture is introduced in laminar flow mode with a flow rate gradient ≤0.01m / s; acetylene pyrolysis generates quasi-one-dimensional carbon nanowires that bridge graphite grain boundaries.

7. The fabrication process of a high-strength ultra-high power graphite electrode according to claim 1, characterized in that, The volatile organic compounds generated during the carbonization process in step S3 are converted into CO2 / H2O through catalytic combustion at 800℃.

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