Production process of graphite electrode of high-sulfur petroleum coke

Abstract

The invention discloses a production process of a graphite electrode of high-sulfur petroleum coke, and relates to the technical field of graphite electrode production, and the production process comprises the following specific steps: raw material pretreatment: crushing high-sulfur petroleum coke of which the sulfur content is greater than or equal to 3.0 wt%, the method has the beneficial effects that the high-sulfur petroleum coke is subjected to deep desulfurization and pre-graphitization through ultra-high-temperature pretreatment, the destructive influence of sulfur content on subsequent procedures is fundamentally eliminated, a highly-ordered graphite crystal structure is formed through combination of optimized grain size distribution and a high-coking-value binder, and the high-sulfur-content petroleum coke is obtained. The method is particularly suitable for high-temperature and high-corrosion environments such as smelting of metal silicon through an ore-smelting electric furnace, high-valued utilization of waste is achieved in the whole process, meanwhile, management is conducted in combination with a system, remote supervision is conveniently conducted on the whole graphite electrode production process, and when a certain link is abnormal, the graphite electrode can be rapidly and accurately produced. And processing can be carried out at the first time, so that the overall intelligent management level is improved.

Description

Technical Field

[0001] This invention relates to the field of graphite electrode production technology, specifically to a production process for graphite electrodes made from high-sulfur petroleum coke. Background Technology

[0002] Graphite electrodes are indispensable high-temperature conductive materials in industries such as electric arc furnace steelmaking, industrial silicon, and yellow phosphorus smelting. Their production typically involves a series of complex processes, including calcination, crushing, batching, kneading, molding, roasting, and graphitization, using petroleum coke and needle coke as aggregates and coal tar pitch as a binder.

[0003] Currently, the production of high-quality graphite electrodes heavily relies on high-quality petroleum coke or expensive needle coke that is low in sulfur (sulfur content < 2.0%) and impurities. However, with the increasing trend of heavier and lower-quality crude oil globally, the output of high-sulfur petroleum coke (sulfur content ≥ 3.0%, even as high as 5-7%), a byproduct of oil refining, is increasing year by year. This type of high-sulfur petroleum coke is quite attractive due to its low cost, but if it is used directly in electrode production, the sulfur in it will precipitate violently in the form of sulfur oxides during subsequent roasting and graphitization processes, leading to microcracks, increased porosity, and loose structure in the product. This severely degrades the electrode's bulk density, mechanical strength, and conductivity, making it unable to meet the stringent requirements of high-temperature electric arc furnaces.

[0004] Chinese Patent Publication No. CN 117430420 A discloses a graphite electrode production process, belonging to the field of graphite electrode production. The process includes steps such as batching, calcination, vibratory sieving and classification, grinding and screening, purification, kneading, mold heating, cooling and compaction, roasting, cleaning, impregnation, graphitization, coating, rotary slag removal, and machining to prepare graphite electrodes. This invention provides a comprehensive and specific production method that increases the quality and yield of graphite electrodes, significantly improves the purity of the prepared graphite electrodes, enhances their performance, and extends their lifespan. The purification process, involving multiple operations such as calcination, vibratory sieving and classification, and purification, is low-cost, simple to operate, and effectively improves the purity of the prepared graphite electrodes. Simultaneously, by monitoring and managing the entire production process, environmental pollution is reduced, production error tolerance is increased, and the integrity of the process operation is improved.

[0005] However, the above solution still has the following problems: High-sulfur petroleum coke is mostly discarded or used as a low-grade fuel in the manufacture of graphite electrodes, which not only wastes resources but also brings environmental pressure. In existing technologies, although there are attempts to treat high-sulfur coke through additives or specific processes, there are often problems such as incomplete desulfurization, complex process flow, high cost, or limited improvement on the final performance of the electrode. At the same time, when abnormalities occur in specific processes, it is difficult to quickly investigate, which increases the overall workload and results in a low level of overall intelligent management, leading to many problems and failing to meet the needs of normal use.

[0006] Therefore, this invention requires the design of a production process for graphite electrodes made from high-sulfur petroleum coke to solve the aforementioned problems. Summary of the Invention

[0007] The purpose of this invention is to provide a new process for efficiently and economically utilizing high-sulfur petroleum coke to produce high-performance graphite electrodes. This process is of great significance for alleviating the shortage of high-quality carbon raw materials, reducing production costs, and realizing the high-value utilization of solid waste, thereby solving the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a production process for graphite electrodes made from high-sulfur petroleum coke, comprising the following specific steps: S1. Raw material pretreatment: High-sulfur petroleum coke with a sulfur content ≥3.0wt% is crushed and then subjected to high-temperature graphitization treatment at 2000-2800℃ for 20-50 hours to obtain graphitized petroleum coke with a sulfur content <0.5wt%. S2. Batching and mixing: The graphitized petroleum coke, calcined petroleum coke and coal tar pitch binder obtained in step S1 are batched and then kneaded for 40-60 minutes at 170-180℃ and a vacuum degree of -0.084 to -0.094 MPa to obtain a paste. S3. Molding: The paste obtained in step S2 is molded under a vacuum of -0.084 to -0.094 MPa and a pressure of 14-18 kg / cm². 2 Under the conditions of pressing and molding, a green body is obtained; S4. Calcination: The green body obtained in step S3 is heated to 1100-1200℃ in a protective medium at a heating rate of 0.5-3.5℃ / h, and then calcined at this temperature for 40-60 hours to obtain the calcined product. S5. Graphitization: The calcined product obtained in step S4 is graphitized at 2800-3000℃ for 24-48 hours, and the graphite electrode is obtained after cooling.

[0009] In a preferred embodiment of the present invention, the ingredients in step S2, by weight percentage, include: Graphitized petroleum coke: 10-40%; Calcinated petroleum coke: 40-70%, with a sulfur content of <0.5wt%; Coal tar pitch binder: 20-24%, with a softening point of 100-120℃ and a coking value ≥58%.

[0010] In a preferred embodiment of the present invention, the particle size range of the graphitized petroleum coke is 0-12 mm, the particle size range of the calcined petroleum coke is 0-16 mm, and a multi-stage particle size distribution is adopted.

[0011] In a preferred embodiment of the present invention, the preferred temperature for the high-temperature graphitization treatment in step S1 is 2500-2800℃, and the preferred time is 45-48 hours.

[0012] In a preferred embodiment of the present invention, the protective medium in step S4 is metallurgical coke particles, and the gradient heating is specifically: the heating rate from room temperature to 500°C is 0.5-2.5°C / h, and the heating rate from 500°C to 1100°C is 1-3.5°C / h.

[0013] In a preferred embodiment of the present invention, the preferred temperature for the graphitization treatment in step S5 is 2800-2900℃.

[0014] In a preferred embodiment of the present invention, the bulk density of the graphite electrode is ≥1.60 g / cm³. 3 Resistivity ≤10 μΩ·m, flexural strength ≥6 MPa, sulfur content <0.1wt%.

[0015] In a preferred embodiment of the present invention, before performing the raw material pretreatment in step S1, a graphite electrode production system needs to be constructed. The graphite electrode production system includes a raw material pretreatment module, a material conveying and batching module, a molding and calcining module, a graphitization module, and a central control module for the production process. All of these modules are bidirectionally connected to the graphite electrode production system. The raw material pretreatment module is responsible for receiving and processing high-sulfur petroleum coke. In step S1, the high-sulfur petroleum coke is deeply desulfurized and pre-graphitized through an ultra-high temperature graphitization furnace, which transforms unqualified raw materials into qualified aggregates for producing high-performance graphite electrodes, thus solving the problem of sulfur hazards from the source. The material conveying and batching module is responsible for accurately and efficiently conveying and weighing pretreated graphitized petroleum coke, calcined petroleum coke and other aggregates and coal tar pitch binder according to the formula requirements of step S2. Automated batching ensures the uniformity and stability of product composition. The molding and roasting module includes a molding unit and a roasting unit. The molding unit inside the molding and roasting module is used to perform steps S2 and S3. Under heating and vacuum conditions, the vacuum kneading pot makes the coal tar pitch uniformly coat and impregnate the aggregate particles, and removes the gas in the material to form a high-density homogeneous paste. The vacuum molding machine presses the paste into a green body with precise dimensions and high initial density under pressure, laying the structural foundation for subsequent roasting. The roasting unit inside the forming roasting module is also used to perform step S4. The ring roasting furnace, through its unique gradient heating control system, slowly carbonizes the coal tar binder in the green and gently precipitates the residual trace sulfur, avoiding micro-cracks and deformation in the product, and forming a roasted product with a certain mechanical strength. The graphitization module is used to perform step S5, which involves directly passing a large current through the calcined product to generate a high temperature of 2800-3000℃, which transforms amorphous carbon into a three-dimensional ordered graphite crystal structure, ultimately achieving the low resistivity, high density and high strength required for the product. The central control module for the production process is used to automatically monitor and schedule the entire production process, ensuring the precise execution of each process parameter, while providing a stable and reliable power supply to the energy-intensive graphitization process.

[0016] In a preferred embodiment of the present invention, the raw material pretreatment module includes the following equipment: a large block crusher, a vibrating screen, a feeder, and an ultra-high temperature graphitization furnace; The material conveying and batching module includes the following equipment: belt conveyor, bucket elevator, automatic batching bin, electronic scale, and DCS; The molding and calcining module includes the following equipment: a preheating kettle, a vacuum mixing pot, a vacuum vibration molding machine, a ring calcining furnace or a tunnel kiln; The graphitization module includes the following equipment: an internal series graphitization furnace, a high-current rectifier transformer system, and cooling equipment; The central control module for the production process includes the following equipment: PLC controller, central control room, dedicated substation, power dispatch center, and circulating water cooling system.

[0017] In a preferred embodiment of the present invention, the large block crusher, vibrating screen, feeder, ultra-high temperature graphitization furnace, belt conveyor, bucket elevator, automatic batching bin, electronic scale, DCS, preheating kettle, vacuum kneading pot, vacuum vibration molding machine, ring roasting furnace, internal series graphitization furnace, high current rectifier transformer system, cooling equipment, central control room, dedicated substation, power dispatch center, and circulating water cooling system are all electrically connected to the PLC controller, which is used to control the operation of the above-mentioned electrical equipment.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention employs ultra-high temperature pretreatment for deep desulfurization and pre-graphitization of high-sulfur petroleum coke, fundamentally eliminating the destructive impact of sulfur on subsequent processes. Optimized particle size distribution combined with a high-coking-value binder, followed by kneading and molding under vacuum, maximizes the compactness of the green body. A carefully designed gradient calcination curve and high-temperature graphitization process ensure the gradual release of residual trace sulfur, forming a highly ordered graphite crystal structure. This results in the production of high-performance graphite electrodes, particularly suitable for high-temperature, highly corrosive environments such as those used in electric arc furnaces for smelting metallic silicon. The entire process achieves high-value utilization of waste, reduces solid waste emissions, and aligns with the development direction of green manufacturing. Furthermore, the integrated system allows for remote monitoring of the entire graphite electrode production process, enabling immediate intervention in case of any abnormalities, thereby improving the overall level of intelligent management. Attached Figure Description

[0019] Figure 1 This is an overall flow chart of the production process of a graphite electrode for high-sulfur petroleum coke according to the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0021] Please see Figure 1 This invention provides a technical solution: a production process for graphite electrodes made from high-sulfur petroleum coke, comprising the following specific steps: S1. Raw material pretreatment: High-sulfur petroleum coke (sulfur content ≥3.0wt%) is crushed to a suitable particle size (e.g., below 25mm), and then placed in a graphitization furnace and treated at an ultra-high temperature of 2000-2800℃ for 20-50 hours. This process can cause most of the sulfur to volatilize and be removed in the form of sulfides, and at the same time cause the petroleum coke to undergo graphitization transformation, resulting in graphitized petroleum coke with a sulfur content of less than 0.5wt%. The preferred temperature for the high-temperature graphitization treatment is 2500-2800℃, and the preferred time is 45-48 hours; S2. Batching and mixing: The graphitized petroleum coke, conventional calcined petroleum coke (sulfur content <0.5%) and coal tar pitch binder are mixed in a specific ratio and kneaded under vacuum (-0.084 to -0.094 MPa) and heating (170-180℃) conditions for 40-60 minutes to make the asphalt evenly coat the aggregate, expel the gas, and form a homogeneous paste. The ingredients, by weight percentage, include: Graphitized petroleum coke: 10-40%; Calcinated petroleum coke: 40-70%, with a sulfur content of <0.5wt%; Coal tar pitch binder: 20-24%, with a softening point of 100-120℃ and a coking value ≥58%; The particle size range of the graphitized petroleum coke is 0-12 mm, and the particle size range of the calcined petroleum coke is 0-16 mm, and multi-stage particle size distribution is adopted. S3. Molding: The paste is placed in the same vacuum environment and at 14-18 kg / cm². 2 The green body is pressed and shaped under pressure to obtain a dense green body; S4. Calcination: The green billet is buried in a protective medium such as metallurgical coke and heated to 1100-1200℃ using a slow gradient heating regime (e.g., 0.5-3.5℃ / h) and held at that temperature for a long time (40-60 hours). This step aims to carbonize the binder and gently and thoroughly release any trace amounts of sulfur that may remain from the previous steps, thus avoiding product cracking due to violent venting. The protective medium is metallurgical coke particles, and the gradient heating is specifically as follows: the heating rate from room temperature to 500℃ is 0.5-2.5℃ / h, and the heating rate from 500℃ to 1100℃ is 1-3.5℃ / h. S5. Graphitization: The calcined product is treated at a final temperature of 2800-3000℃ for 24-48 hours to transform amorphous carbon into three-dimensional ordered graphite crystals, thereby obtaining a graphite electrode with excellent electrical and thermal conductivity. The preferred temperature for the graphitization treatment is 2800-2900℃.

[0022] The obtained graphite electrode has a bulk density ≥1.60 g / cm³. 3 Resistivity ≤10 μΩ·m, flexural strength ≥6 MPa, sulfur content <0.1wt%.

[0023] Before performing the raw material pretreatment in step S1, a graphite electrode production system needs to be constructed. This system includes a raw material pretreatment module, a material conveying and batching module, a molding and calcination module, a graphitization module, and a central control module for the production process. All of these modules are bidirectionally connected to the graphite electrode production system. The raw material pretreatment module includes the following equipment: a large block crusher, a vibrating screen, a feeder, and an ultra-high temperature graphitization furnace; The raw material pretreatment module is responsible for receiving and processing high-sulfur petroleum coke. In step S1, the high-sulfur petroleum coke is deeply desulfurized (sulfur content is reduced from ≥3.0% to <0.5%) and pre-graphitized in an ultra-high temperature graphitization furnace, transforming unqualified raw materials into qualified aggregates for producing high-performance graphite electrodes, thus solving the problem of sulfur hazards from the source. The material conveying and batching module includes the following equipment: belt conveyor, bucket elevator, automatic batching bin, electronic scale, and DCS (distributed control system). The material conveying and batching module is responsible for accurately and efficiently conveying and weighing pretreated graphitized petroleum coke, calcined petroleum coke and other aggregates and coal tar pitch binder according to the formula requirements of step S2. Automated batching ensures the uniformity and stability of product composition. The molding and roasting module includes a molding unit and a roasting unit. The molding unit inside the molding and roasting module is used to perform steps S2 and S3. Under heating and vacuum conditions, the vacuum kneading pot makes the coal tar pitch uniformly coat and impregnate the aggregate particles, and removes the gas in the material to form a high-density homogeneous paste. The vacuum molding machine presses the paste into a green body with precise dimensions and high initial density under pressure, laying the structural foundation for subsequent roasting. The molding and calcining module includes the following equipment: a preheating kettle, a vacuum mixing pot, a vacuum vibration molding machine, a ring calcining furnace or a tunnel kiln; The roasting unit inside the forming roasting module is also used to perform step S4. The ring roasting furnace, through its unique gradient heating control system, slowly carbonizes the coal tar binder in the green and gently precipitates the residual trace sulfur, avoiding micro-cracks and deformation in the product, and forming a roasted product with a certain mechanical strength. The graphitization module includes the following equipment: an internal series graphitization furnace, a high-current rectifier transformer system, and cooling equipment; The graphitization module is used to perform step S5, which involves directly passing a large current through the calcined product to generate a high temperature of 2800-3000℃, which transforms amorphous carbon into a three-dimensional ordered graphite crystal structure, ultimately achieving the low resistivity, high density and high strength required for the product. The central control module for the production process includes the following equipment: PLC controller, central control room (PLC / DCS / SCADA system), dedicated substation, power dispatch center, and circulating water cooling system; The central control module for the production process is used to automatically monitor and schedule the entire production process, ensuring the precise execution of each process parameter (temperature, vacuum, pressure, heating curve), while providing a stable and reliable power supply to the energy-intensive graphitization process.

[0024] The large-scale crusher, vibrating screen, feeder, ultra-high temperature graphitization furnace, belt conveyor, bucket elevator, automatic batching silo, electronic scale, DCS, preheating kettle, vacuum kneading pot, vacuum vibration molding machine, ring roasting furnace, internal series graphitization furnace, high current rectifier transformer system, cooling equipment, central control room, dedicated substation, power dispatch center, and circulating water cooling system are all electrically connected to the PLC controller, which is used to control the operation of the above-mentioned electrical equipment.

[0025] Example 1 Raw material pretreatment: High-sulfur petroleum coke with a sulfur content of 3.8 wt% was taken, crushed into particles smaller than 20 mm, and then fed into an Atchison graphitization furnace. It was treated at 2600℃ for 48 hours to obtain graphitized petroleum coke, whose sulfur content was reduced to 0.3 wt% upon testing. Ingredients: Weigh out by weight percentage: The above-mentioned graphitized petroleum coke (particle size 0-8mm): 30%; Calcined petroleum coke (sulfur content 0.4%, particle size classification: 4-16mm accounts for 40%, 0-4mm accounts for 30%): a portion of 70%; Coal tar pitch binder (softening point 120℃, coking value 60%): 22%; Mixing: Preheat the dry materials (two types of petroleum coke) to 175°C in a kneader, vacuum to -0.09 MPa, then add molten coal tar pitch and knead for 50 minutes under these conditions. Molding: The paste is transferred to a molding machine and pressed under a vacuum of -0.09 MPa at a rate of 16 kg / cm³. 2 The pressure is used to press the standard electrode green blank into a standard electrode blank; Calcination: The green billet is buried in metallurgical coke filler and placed in a ring-type calcining furnace. The temperature is increased to 500℃ at 1.5℃ / h, then increased to 1150℃ at 2℃ / h, and kept at 1150℃ for 50 hours. Then it is naturally cooled to room temperature. Graphitization: The calcined product is placed in a graphitization furnace, heated to 2850°C, and kept at that temperature for 30 hours, and then slowly cooled. Performance testing: The obtained graphite electrode was subjected to performance testing, and the results were: bulk density 1.63 g / cm³. 3 With a resistivity of 9.2 μΩ·m, a flexural strength of 6.8 MPa, and a sulfur content of 0.05wt%, the production cost is reduced by approximately 25% compared to the traditional process using pure low-sulfur petroleum coke. Example 2 Raw material pretreatment: High-sulfur petroleum coke with a sulfur content of 4.5 wt% was crushed and treated at 2400℃ for 45 hours to obtain graphitized petroleum coke with a sulfur content of 0.4 wt%. Ingredients: Weigh out by weight percentage: Graphitized petroleum coke (particle size 0-10mm): 20%; Calcinated petroleum coke (sulfur content 0.3%, particle size classification): 60%; Coal tar pitch binder (softening point 110℃, coking value 59%): 20%; Subsequent steps: The mixing, molding, firing, and graphitization process parameters are the same as in Example 1; Performance testing: The bulk density of the obtained graphite electrode was 1.61 g / cm³. 3 It has a resistivity of 9.8 μΩ·m, a flexural strength of 6.2 MPa, and a sulfur content of 0.07 wt%. Cost is reduced by approximately 21%. Comparative Example 1 (Traditional Process) Low-sulfur petroleum coke with a sulfur content of 0.5% and the same type of coal tar pitch were used directly, without a pre-graphitization desulfurization step. Mixing and molding were carried out under normal pressure, and the calcination curve adopted a conventional heating rate (average 3℃ / h). The final graphite electrode properties were: bulk density 1.58 g / cm³. 3 Resistivity 11.5 μΩ·m, flexural strength 5.5 MPa; Comparative Example 2 (High-sulfur coke used directly) The high-sulfur petroleum coke (sulfur content 3.8%) without pretreatment from Example 1 was used directly as a feedstock to replace the graphitized petroleum coke. All other conditions were exactly the same as in Example 1. During the graphitization stage, the product showed obvious longitudinal and transverse cracks, making it impossible to conduct effective performance testing.

[0026] The test results are shown in the table below: Test method description: To verify the effectiveness of this invention, the performance tests of all graphite electrode samples in the examples and comparative examples were conducted in accordance with the following National Standard of the People's Republic of China (GB / T): The sulfur content was determined according to GB / T 24526-2009 "Determination of Total Sulfur Content in Carbon Materials"; Bulk density is determined according to GB / T 24203-2024 "Bulk density, true density, true porosity, and carbon materials". The apparent porosity was determined according to the "Method for Determining Apparent Porosity". The resistivity was measured according to GB / T24525-2009 "Method for Determination of Resistivity of Carbon Materials".

[0027] The flexural strength was determined according to GB / T 3074.1-2021 "Determination of Flexural Strength of Carbon Materials".

[0028] Conclusion: The data above shows that the process of this invention, through innovative pretreatment of high-sulfur petroleum coke and subsequent process optimization, not only successfully transforms high-sulfur waste into qualified raw materials and significantly reduces costs, but also produces graphite electrodes that are superior to similar products produced by traditional processes in key performance indicators. The failure of Comparative Example 2 proves that it is impossible to produce qualified graphite electrodes without pretreatment of high-sulfur coke, highlighting the necessity and criticality of the pre-graphitization desulfurization step of this invention. This invention utilizes ultra-high temperature pretreatment to deeply desulfurize and pre-graphitize high-sulfur petroleum coke, fundamentally eliminating the destructive impact of sulfur on subsequent processes. By combining optimized particle size distribution with a high coking value binder and kneading and molding under vacuum, the density of the green body is maximized. Through a carefully designed gradient calcination curve and high-temperature graphitization process, the residual trace sulfur is released gradually, forming a highly ordered graphite crystal structure, thereby producing a high-performance graphite electrode. This process successfully transforms inexpensive, waste-grade high-sulfur petroleum coke (sulfur content ≥3.0%) into a raw material for high-quality graphite electrodes, increasing the utilization rate of high-sulfur petroleum coke by over 50% and reducing overall production costs by over 20%. The graphite electrodes prepared using this process achieve a bulk density of 1.60 g / cm³. 3 The resistivity is below 10 μΩ·m and the flexural strength exceeds 6MPa. The key performance indicators fully meet or even exceed the standards for electrodes produced using traditional low-sulfur coke as raw material. It is especially suitable for high-temperature and highly corrosive environments such as smelting metallic silicon in electric arc furnaces. The entire process realizes the high-value utilization of waste, reduces solid waste emissions, and conforms to the development direction of green manufacturing. At the same time, it is combined with system management, which facilitates remote monitoring of the entire graphite electrode production process. When an abnormality occurs in a certain link, it can be dealt with immediately, thereby improving the overall level of intelligent management.

[0029] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A production process for graphite electrodes made from high-sulfur petroleum coke, characterized in that, The specific steps include the following: S1. Raw material pretreatment: High-sulfur petroleum coke with a sulfur content ≥3.0wt% is crushed and then subjected to high-temperature graphitization treatment at 2000-2800℃ for 20-50 hours to obtain graphitized petroleum coke with a sulfur content <0.5wt%. S2. Batching and kneading: The graphitized petroleum coke, calcined petroleum coke and coal tar pitch binder obtained in step S1 are batched and then kneaded for 40-60 minutes at 170-180℃ and a vacuum degree of -0.084 to -0.094 MPa to obtain a paste. S3. Molding process: The paste obtained in step S2 is subjected to a vacuum degree of -0.084 to -0.094 MPa and a pressure of 14-18 kg / cm². 2 Under the conditions of pressing and molding, a green body is obtained; S4. Calcination treatment: The green body obtained in step S3 is heated to 1100-1200℃ in a protective medium at a heating rate of 0.5-3.5℃ / h, and then calcined at this temperature for 40-60 hours to obtain the calcined product. S5. Graphitization treatment: The calcined product obtained in step S4 is graphitized at 2800-3000℃ for 24-48 hours, and the graphite electrode is obtained after cooling.

2. The production process of graphite electrodes from high-sulfur petroleum coke according to claim 1, characterized in that: The ingredients in step S2, by weight percentage, include: Graphitized petroleum coke: 10-40%; Calcinated petroleum coke: 40-70%, with a sulfur content of <0.5wt%; Coal tar pitch binder: 20-24%, with a softening point of 100-120℃ and a coking value ≥58%.

3. The production process of graphite electrodes from high-sulfur petroleum coke according to claim 2, characterized in that: The graphitized petroleum coke has a particle size range of 0-12 mm, and the calcined petroleum coke has a particle size range of 0-16 mm, and adopts multi-stage particle size distribution.

4. The production process of graphite electrodes from high-sulfur petroleum coke according to claim 3, characterized in that: The preferred temperature for the high-temperature graphitization treatment in step S1 is 2500-2800℃, and the preferred time is 45-48 hours.

5. The production process of graphite electrodes from high-sulfur petroleum coke according to claim 1, characterized in that: The protective medium in step S4 is metallurgical coke particles, and the gradient heating is specifically as follows: the heating rate from room temperature to 500℃ is 0.5-2.5℃ / h, and the heating rate from 500℃ to 1100℃ is 1-3.5℃ / h.

6. The production process of graphite electrodes from high-sulfur petroleum coke according to claim 1, characterized in that: The preferred temperature for the graphitization process in step S5 is 2800-2900℃.

7. The production process of graphite electrodes from high-sulfur petroleum coke according to claim 1, characterized in that: The graphite electrode has a bulk density ≥1.60 g / cm³. 3 Resistivity ≤10 μΩ·m, flexural strength ≥6 MPa, sulfur content <0.1wt%.

8. The production process of graphite electrodes from high-sulfur petroleum coke according to claim 6, characterized in that: Before performing the raw material pretreatment in step S1, a graphite electrode production system needs to be constructed. This system includes a raw material pretreatment module, a material conveying and batching module, a molding and calcination module, a graphitization module, and a central control module for the production process. All of these modules are bidirectionally connected to the graphite electrode production system. The raw material pretreatment module is responsible for receiving and processing high-sulfur petroleum coke, and achieving deep desulfurization and pre-graphitization of high-sulfur petroleum coke in step S1 through an ultra-high temperature graphitization furnace. The material conveying and batching module is responsible for accurately and efficiently conveying and weighing the pretreated graphitized petroleum coke, calcined petroleum coke and other aggregates and coal tar pitch binder according to the formula requirements of step S2. The molding and roasting module includes a molding unit and a roasting unit. The molding unit inside the molding and roasting module is used to perform steps S2 and S3. Under heating and vacuum conditions, the vacuum mixing pot makes the coal tar pitch uniformly coat and impregnate the aggregate particles, and removes the gas in the material to form a high-density homogeneous paste. The roasting unit inside the forming roasting module is also used to perform step S4. The ring roasting furnace, through its unique gradient heating control system, slowly carbonizes the coal tar binder in the green and gently precipitates the residual trace sulfur. The graphitization module is used to perform step S5, which involves directly passing a large current through the calcined product to generate a high temperature of 2800-3000℃, thereby transforming amorphous carbon into a three-dimensional ordered graphite crystal structure. The central control module for the production process is used to automatically monitor and schedule the entire production process, ensuring the precise execution of each process parameter, while providing a stable and reliable power supply to the energy-intensive graphitization process.

9. The production process of graphite electrodes from high-sulfur petroleum coke according to claim 8, characterized in that: The raw material pretreatment module includes the following equipment: a large block crusher, a vibrating screen, a feeder, and an ultra-high temperature graphitization furnace; The material conveying and batching module includes the following equipment: belt conveyor, bucket elevator, automatic batching bin, electronic scale, and DCS; The molding and calcining module includes the following equipment: a preheating kettle, a vacuum mixing pot, a vacuum vibration molding machine, a ring calcining furnace or a tunnel kiln; The graphitization module includes the following equipment: an internal series graphitization furnace, a high-current rectifier transformer system, and cooling equipment; The central control module for the production process includes the following equipment: PLC controller, central control room, dedicated substation, power dispatch center, and circulating water cooling system.

10. The production process of graphite electrodes from high-sulfur petroleum coke according to claim 9, characterized in that: The large-scale crusher, vibrating screen, feeder, ultra-high temperature graphitization furnace, belt conveyor, bucket elevator, automatic batching silo, electronic scale, DCS, preheating kettle, vacuum kneading pot, vacuum vibration molding machine, ring roasting furnace, internal series graphitization furnace, high current rectifier transformer system, cooling equipment, central control room, dedicated substation, power dispatch center, and circulating water cooling system are all electrically connected to the PLC controller, which is used to control the operation of the above-mentioned electrical equipment.

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