High-conductivity and high-heat-conductivity carbon electrode and preparation method thereof

Abstract

The invention relates to the technical field of carbon electrodes, in particular to a high-electric-conductivity and high-heat-conductivity carbon electrode and a preparation method thereof. The electrode raw materials comprise a solid mixture and graphene reinforced coal pitch; the solid mixture comprises the following components in percentage by mass: 60-90% of calcined petroleum coke and 10-40% of graphite scraps; raw materials of the graphene reinforced coal pitch comprise liquid coal pitch and graphene aqueous slurry; the graphene aqueous slurry is composed of water and graphene, and the weight part ratio of the water to the graphene is 10: (1-1.5); the mass of the graphene reinforced coal pitch accounts for 15-25% of the total mass of the solid mixture and the graphene reinforced coal pitch; the mass of graphene in the graphene reinforced coal pitch accounts for 0.05-0.5% of the total mass of the graphene aqueous slurry and the liquid coal pitch. The invention also provides a preparation method of the electrode, and the carbon electrode prepared by the preparation method has high electric conductivity and thermal conductivity, so that the utilization efficiency of energy can be improved, and the service life of the electrode can be prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon electrodes, and particularly relates to a highly conductive and thermally conductive carbon electrode and a preparation method thereof. Background Art

[0002] Carbon electrodes are mainly used in submerged arc furnaces for smelting industrial silicon, ferroalloys, yellow phosphorus, calcium carbide, etc. The types of raw materials, the ratio between raw materials, and the preparation method and other processes have a significant impact on the performance of the final product.

[0003] The applicant has conducted a large number of studies on carbon electrodes and achieved a large number of results, such as CN106376121B A High Graphitic Carbon Electrode and Its Preparation Method, CN104837233B A Method for Making an Enhanced Composite Graphite Electrode, etc.

[0004] In recent years, graphene has been widely concerned due to its excellent electronic conductivity and large specific surface area. How to apply graphene materials to carbon electrodes to improve the performance of the finished electrodes has become a new topic in the electrode production and research and development process.

[0005] In order to conform to the development trend of high power, and further improve the electric energy input furnace efficiency and the thermoelectric conversion rate, the present invention provides a highly conductive and thermally conductive carbon electrode by adjusting the types of raw materials, the ratio, and the preparation process conditions, and utilizing the characteristics of high ion mobility of graphene. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a highly conductive and thermally conductive carbon electrode and a preparation method thereof.

[0007] To solve the above problems, the technical solutions adopted by the present invention are as follows: Technical Theme 1 A highly conductive and thermally conductive carbon electrode, the raw materials of which include a solid mixture and graphene-reinforced coal tar pitch; The solid mixture includes the following components in mass percentage: 60 - 90% of calcined petroleum coke, 10 - 40% of graphite fines; The raw materials of the graphene-reinforced coal tar pitch include liquid coal tar pitch and graphene aqueous slurry; The graphene aqueous slurry is composed of water and graphene, and the weight ratio of water to graphene is 10:1 - 1.5; The graphene-reinforced coal tar pitch accounts for 15% - 25% of the total mass of the solid mixture and the graphene-reinforced coal tar pitch; The mass of graphene in the graphene-reinforced coal tar pitch accounts for 0.05% - 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar pitch.

[0008] As a further improvement of the present invention, the graphene aqueous slurry further contains cellulose, and the weight ratio of water, graphene, and cellulose is 10: 1-1.5: 0.05-0.15.

[0009] As a further improvement of the present invention, the cellulose is water-soluble cellulose.

[0010] As a further improvement of the present invention, the calcined petroleum coke is low-sulfur petroleum coke treated at high temperature, and the mass percentage of sulfur <0.5%; The coal tar pitch is medium-temperature modified pitch prepared by the Coppus process, and the softening point is 90-100 °C; The graphene aqueous slurry is an aqueous slurry prepared by using graphene powder materials with less than 10 layers; The graphite scraps are graphitization waste products generated by electrode carbon products; As a further improvement of the present invention, the solid mixture includes the following components in mass percentage: 70-80% of calcined petroleum coke, 20-30% of graphite scraps; The graphene-reinforced coal tar pitch accounts for 20%-21% of the total mass of the solid mixture and the graphene-reinforced coal tar pitch.

[0011] As a further improvement of the present invention, the solid mixture includes the following components in mass percentage: 75% of calcined petroleum coke, 25% of graphite scraps; The graphene aqueous slurry further contains cellulose, and the weight ratio of water, graphene, and cellulose is 10: 1: 0.1; The graphene-reinforced coal tar pitch accounts for 20% of the total mass of the solid mixture and the graphene-reinforced coal tar pitch; The mass of graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar pitch; As a further improvement of the present invention, the cellulose is selected from carboxymethyl cellulose.

[0012] As a further improvement of the present invention, the diameter of the high-conductivity and high-heat-conductivity carbon electrode is 1020 mm-1400 mm.

[0013] Technical theme two A preparation method of a high-conductivity and high-heat-conductivity carbon electrode as described in Technical Theme One, which includes the following steps: S1: Crush, screen, and grind graphite scraps and calcined petroleum coke respectively to obtain granular materials for standby; S2: Mix graphene, water, and cellulose to obtain graphene aqueous slurry for standby; S3: Add the graphene aqueous slurry to the liquid coal tar pitch, stir evenly, heat to a constant temperature of 160 - 170 °C, and let the aqueous solvent in the graphene aqueous slurry volatilize to obtain graphene-reinforced coal tar pitch; S4: Weigh the solid mixture according to the particle size and proportion, convey the prepared solid mixture to a dry material electric heating box for heating and mixing. The dry mixing time is 20 - 40 min, and the final dry mixing temperature is 120 - 180 °C; S5: Convey the heated and mixed solid mixture obtained in S4 to a kneading pot, add the graphene-reinforced coal tar pitch prepared in S3 for wet mixing. The use temperature of the liquid coal tar pitch is 160 - 170 °C, the wet mixing time is 30 - 50 min, and the temperature of the discharged paste is 160 - 180 °C; S6: Feed the paste into a cooling machine to cool it to 130 - 160 °C and then into a mold for forming. After demolding, the green product is conveyed to a water tank for cooling for 2 - 3 h; S7: Feed the green product into an annular roasting furnace for heat treatment. The highest heat treatment temperature is 800 - 1000 °C, the roasting cycle is 980 - 1450 h, the holding time at the highest temperature is 48 h - 72 h, and the discharging temperature is from room temperature to 300 °C; S8: Clean the roasted product and then feed it into an internal series graphitization furnace for graphitization treatment. The graphitization power-on time is 30 - 40 h, and the power consumption per ton of roasted product is 3000 - 3500 kWh; S9: Carry out machining according to the product specifications and drawing requirements.

[0014] As a further improvement of the present invention, when weighing the solid mixture according to the particle size and proportion, the amount of powder less than 1 mm accounts for 40 - 50% of the total mass of the solid material, the particle size of 1 - 4 mm accounts for 15 - 25% of the total mass of the solid material, the particle size of 4 - 10 mm accounts for 20 - 30% of the total mass of the solid material, and the particle size of 10 - 16 mm accounts for 5 - 15% of the total mass of the solid material.

[0015] As a further improvement of the present invention, in S6, when feeding into the cooling machine for cooling, the asphalt fumes in the paste are removed by means of vacuum pumping, and the forming is carried out by means of variable-frequency vibration and upper and lower pressurization of the mold. After forming, the green blank is cooled by passing water in the mold for 50 - 80 min and then demolded.

[0016] As a further improvement of the present invention, the roasting curve in S7 is: room temperature - 250 °C, heating rate 1 - 1.5 °C / h; 251 - 600 °C, heating rate 0.4 - 0.6 °C / h; 601 - 950 °C, heating rate 1 - 1.5 °C / h.

[0017] The beneficial effects produced by adopting the above technical solutions are as follows: The present invention provides a highly conductive and thermally conductive carbon electrode. By selecting the types of raw materials and the ratio between the raw materials, the electrode has good electrical and thermal conductivity.

[0018] The present invention also provides a preparation method of the electrode. By adding a graphene aqueous slurry containing graphene and cellulose into liquid coal tar pitch, cellulose serves as a graphene dispersion aid, which is beneficial to the dispersion of graphene. Graphene is doped in the electrode paste. After processes such as molding, roasting, and graphitization, it plays a role of network bridging inside the electrode, which can reduce the resistivity of the carbon electrode, improve the thermal conductivity and the electrode usage efficiency, and greatly reduce the fracture risk of the electrode caused by thermal stress. Specific embodiments

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be clearly and completely described below in conjunction with specific embodiments.

[0020] In the following embodiments, the particle size of calcined petroleum coke is: 0 - 0.075 mm powder, 1 - 4 mm (excluding 4 mm), 4 - 10 mm (excluding 10 mm), 10 - 16 mm; the particle size of graphite fragments is powder with a particle size of less than 1 mm, 1 - 4 mm (excluding 4 mm), 4 - 10 mm (excluding 10 mm), 10 - 16 mm.

[0021] In the following embodiments, the solid mixture contains the following weight parts: 36% of 0 - 0.075 mm powder in calcined petroleum coke, 15% of 1 - 4 mm (excluding 4 mm) powder, 20% of 4 - 10 mm (excluding 10 mm) powder, 5% of 10 - 16 mm powder; 8% of powder with a particle size of less than 1 mm in graphite fragments, 4% of 1 - 4 mm (excluding 4 mm), 6% of 4 - 10 mm (excluding 10 mm), 6% of 10 - 16 mm.

[0022] In the following embodiments, the cellulose selected is commercially available carboxymethyl cellulose.

[0023] The calcined petroleum coke is low - sulfur petroleum coke treated at high temperature, and the mass percentage of sulfur < 0.5%.

[0024] Example 1 S1: Crush, screen, and grind graphite fragments and calcined petroleum coke respectively to obtain particulate materials; S2: Under the condition of adding 0.1 weight part of cellulose, mix 1 weight part of graphene powder with less than 10 carbon atom layers and 10 weight parts of deionized water, and prepare a graphene aqueous slurry through high - speed mechanical stirring.

[0025] S3: adding graphene aqueous slurry to liquid coal tar, wherein the graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar, and mixing the graphene aqueous slurry with the liquid coal tar by mechanical stirring, and volatilizing the aqueous solvent in the graphene aqueous slurry by keeping the liquid coal tar at a constant temperature of 160-170° C., thereby obtaining graphene-enhanced coal tar with good dispersibility; S4: Prepare the solid mixture according to the particle size and proportion, wherein the solid mixture includes the following components by mass percentage: 75% calcined petroleum coke and 25% graphite powder. Transport the prepared solid mixture to the dry material electric heating box for heating and mixing, the dry mixing time is 35 minutes, and the final dry mixing temperature is 140°C; S5: conveying the heated mixed solid mixture obtained in S4 to a kneading pot, adding the graphene-enhanced coal tar pitch prepared in S2 for wet mixing, wherein the graphene-enhanced coal tar pitch accounts for 20% of the total mass of the solid mixture and the graphene-enhanced coal tar pitch, the use temperature of the graphene-enhanced coal tar pitch is 170° C., the wet mixing time is 40 min, and the temperature of the paste out of the pot is 170° C.; S6: The paste is sent to a cooler to cool to 140°C and then put into a mold for molding. After demolding, the raw product is sent to a water pool for cooling for 3 hours; S7: sending the raw product into a ring roasting furnace for heat treatment, the highest heat treatment temperature is 950°C, the roasting curve is: room temperature-250°C, heating rate 1°C / h; 251-600°C, heating rate 0.5°C / h; 601-950°C, heating rate 1.5°C / h, the furnace temperature is not higher than 300°C; S8: After cleaning the calcined product, send it to the internal graphitization furnace for graphitization treatment. The graphitization power supply time is 36 hours, and the power supply per ton of calcined product is 3100kWh; S9: Perform machining according to product specifications and drawing requirements.

[0026] Example 2 S1: crushing, screening and grinding graphite and calcined petroleum coke to obtain pellets; S2: 1 part by weight of graphene powder having less than 10 carbon atomic layers and 10 parts by weight of deionized water are mixed with 0.1 parts by weight of cellulose, and then stirred at high speed to obtain an aqueous graphene slurry.

[0027] S3: adding graphene aqueous slurry to liquid coal tar, wherein the graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar, and mixing the graphene aqueous slurry with the liquid coal tar by mechanical stirring, and volatilizing the aqueous solvent in the graphene aqueous slurry by keeping the liquid coal tar at a constant temperature of 160-170° C., thereby obtaining graphene-enhanced coal tar with good dispersibility; S4: Prepare the solid mixture according to the particle size and proportion, wherein the solid mixture includes the following components by mass percentage: 60% calcined petroleum coke and 40% graphite powder. The prepared solid mixture is transported to the dry material electric heating box for heating and mixing, the dry mixing time is 35 minutes, and the final dry mixing temperature is 140°C; S5: conveying the heated mixed solid mixture obtained in S4 to a kneading pot, adding the graphene-enhanced coal tar pitch prepared in S2 for wet mixing, wherein the graphene-enhanced coal tar pitch accounts for 20% of the total mass of the solid mixture and the graphene-enhanced coal tar pitch, the use temperature of the graphene-enhanced coal tar pitch is 170° C., the wet mixing time is 40 min, and the temperature of the paste out of the pot is 170° C.; S6: The paste is sent to a cooler to cool to 140°C and then put into a mold for molding. After demolding, the raw product is sent to a water pool for cooling for 3 hours; S7: sending the raw product into a ring roasting furnace for heat treatment, the highest heat treatment temperature is 950°C, the roasting curve is: room temperature-250°C, heating rate 1°C / h; 251-600°C, heating rate 0.5°C / h; 601-950°C, heating rate 1.5°C / h, the furnace temperature is not higher than 300°C; S8: After cleaning the calcined product, send it to the internal graphitization furnace for graphitization treatment. The graphitization power supply time is 36 hours, and the power supply per ton of calcined product is 3100kWh; S9: Perform machining according to product specifications and drawing requirements.

[0028] Example 3 S1: crushing, screening and grinding graphite and calcined petroleum coke to obtain pellets; S2: 1 part by weight of graphene powder having less than 10 carbon atomic layers and 10 parts by weight of deionized water are mixed with 0.1 parts by weight of cellulose, and then stirred at high speed to obtain an aqueous graphene slurry.

[0029] S3: adding graphene aqueous slurry to liquid coal tar, wherein the graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar, and mixing the graphene aqueous slurry with the liquid coal tar by mechanical stirring, and volatilizing the aqueous solvent in the graphene aqueous slurry by keeping the liquid coal tar at a constant temperature of 160-170° C., thereby obtaining graphene-enhanced coal tar with good dispersibility; S4: Prepare the solid mixture according to the particle size and proportion, wherein the solid mixture includes the following components by mass percentage: 90% calcined petroleum coke and 10% graphite powder. The prepared solid mixture is transported to the dry material electric heating box for heating and mixing, the dry mixing time is 35 minutes, and the final dry mixing temperature is 140°C; S5: Transfer the heated and mixed solid mixture obtained in S4 to a kneading pot, add the graphene-reinforced coal pitch prepared in S2 for wet mixing. The graphene-reinforced coal pitch accounts for 20% of the total mass of the solid mixture and the graphene-reinforced coal pitch. The use temperature of the graphene-reinforced coal pitch is 170 °C, the wet mixing time is 40 min, and the temperature of the discharged paste is 170 °C; S6: Send the paste to a cooling machine to cool it to 140 °C and then mold it. After demolding, the green product is transported to a water tank for cooling for 3 h; S7: Send the green product to an annular roasting furnace for heat treatment. The highest heat treatment temperature is 950 °C, and the roasting curve is as follows: room temperature - 250 °C, heating rate 1 °C / h; 251 - 600 °C, heating rate 0.5 °C / h; 601 - 950 °C, heating rate 1.5 °C / h, and the discharging temperature is not higher than 300 °C; S8: Clean the roasted product and then send it to an internal series graphitization furnace for graphitization treatment. The graphitization power-on time is 36 h, and the power consumption per ton of roasted product is 3100 kWh; S9: Perform machining according to product specifications and drawing requirements.

[0030] Example 4 S1: Crush, screen, and grind graphite fragments and calcined petroleum coke respectively to obtain granular materials; S2: Under the condition of adding 0.1 part by weight of cellulose, mix 1 part by weight of graphene powder with less than 10 carbon atom layers and 10 parts by weight of deionized water, and prepare a graphene aqueous slurry through high-speed mechanical stirring.

[0031] S3: Add the graphene aqueous slurry to liquid coal pitch. The graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal pitch. Mix them evenly with the liquid coal pitch through mechanical stirring. By keeping the liquid coal pitch at a constant temperature of 160 - 170 °C, the aqueous solvent in the graphene aqueous slurry is volatilized to obtain a graphene-reinforced coal pitch with good dispersibility; S4: Weigh and mix the solid mixture according to the particle size and ratio. The solid mixture includes the following components by mass percentage: 75% of calcined petroleum coke and 25% of graphite fragments. Transfer the prepared solid mixture to a dry material electric heating box for heating and mixing. The dry mixing time is 35 min, and the final dry mixing temperature is 140 °C; S5: Transfer the heated and mixed solid mixture obtained in S4 to a kneading pot, add the graphene-reinforced coal pitch prepared in S2 for wet mixing. The graphene-reinforced coal pitch accounts for 25% of the total mass of the solid mixture and the graphene-reinforced coal pitch. The use temperature of the graphene-reinforced coal pitch is 170 °C, the wet mixing time is 40 min, and the temperature of the discharged paste is 170 °C; S6: Send the paste to a cooling machine to cool it to 140 °C and then mold it. After demolding, the green product is transported to a water tank for cooling for 3 h; S7: Feed the green product into a ring-type roasting furnace for heat treatment. The maximum heat treatment temperature is 950 °C, and the roasting curve is as follows: from room temperature to 250 °C, the heating rate is 1 °C / h; from 251 to 600 °C, the heating rate is 0.5 °C / h; from 601 to 950 °C, the heating rate is 1.5 °C / h, and the furnace outlet temperature is not higher than 300 °C. S8: Clean the roasted product and then feed it into an internal-series graphitization furnace for graphitization treatment. The graphitization power-on time is 36 h, and the power consumption per ton of roasted product is 3100 kWh. S9: Perform machining according to the product specifications and drawing requirements.

[0032] Example 5 S1: Crush, screen, and grind graphite fragments and calcined petroleum coke respectively to obtain granular materials. S2: Under the condition of adding 0.1 part by weight of cellulose, mechanically stir 1 part by weight of graphene powder with less than 10 carbon atom layers and 10 parts by weight of deionized water at high speed to prepare graphene aqueous slurry.

[0033] S3: Add the graphene aqueous slurry to liquid coal tar pitch. The graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and liquid coal tar pitch. Mix them evenly by mechanical stirring. By keeping the liquid coal tar pitch at a constant temperature of 160 - 170 °C, volatilize the aqueous solvent in the graphene aqueous slurry to obtain graphene-reinforced coal tar pitch with good dispersion. S4: Weigh the solid mixture according to the particle size and proportion. The solid mixture includes the following components by mass percentage: 75% of calcined petroleum coke and 25% of graphite fragments. Convey the prepared solid mixture to a dry material electric heating box for heating and mixing. The dry mixing time is 40 min, and the final dry mixing temperature is 180 °C. S5: Convey the heated and mixed solid mixture obtained in S4 to a kneading pot, add the graphene-reinforced coal tar pitch prepared in S2 for wet mixing. The graphene-reinforced coal tar pitch accounts for 15% of the total mass of the solid mixture and the graphene-reinforced coal tar pitch. The use temperature of the graphene-reinforced coal tar pitch is 170 °C, the wet mixing time is 40 min, and the temperature of the discharged paste is 170 °C. S6: Feed the paste into a cooling machine to cool it to 130 °C, then put it into a mold for forming. After demolding, convey the green product to a water tank for cooling for 3 h. S7: Feed the green product into a ring-type roasting furnace for heat treatment. The maximum heat treatment temperature is 950 °C, and the roasting curve is as follows: from room temperature to 250 °C, the heating rate is 1 °C / h; from 251 to 600 °C, the heating rate is 0.5 °C / h; from 601 to 950 °C, the heating rate is 1.5 °C / h, and the furnace outlet temperature is not higher than 300 °C. S8: After cleaning the calcined product, send it to the internal graphitization furnace for graphitization treatment. The graphitization power supply time is 36 hours, and the power supply per ton of calcined product is 3100kWh; S9: Perform machining according to product specifications and drawing requirements.

[0034] Example 6 S1: crushing, screening and grinding graphite and calcined petroleum coke to obtain pellets; S2: 1 part by weight of graphene powder having less than 10 carbon atomic layers and 10 parts by weight of deionized water are mixed with 0.1 parts by weight of cellulose, and then stirred at high speed to obtain an aqueous graphene slurry.

[0035] S3: adding graphene aqueous slurry to liquid coal tar, wherein the graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar, and mixing the graphene aqueous slurry with the liquid coal tar by mechanical stirring, and volatilizing the aqueous solvent in the graphene aqueous slurry by keeping the liquid coal tar at a constant temperature of 160-170° C., thereby obtaining graphene-enhanced coal tar with good dispersibility; S4: Prepare the solid mixture according to the particle size and proportion, wherein the solid mixture includes the following components by mass percentage: 75% calcined petroleum coke and 25% graphite powder. The prepared solid mixture is transported to the dry material electric heating box for heating and mixing, the dry mixing time is 40 minutes, and the final dry mixing temperature is 120°C; S5: conveying the heated and mixed solid mixture obtained in S4 to a kneading pot, adding the graphene-enhanced coal tar pitch prepared in S2 for wet mixing, wherein the graphene-enhanced coal tar pitch accounts for 20% of the total mass of the solid mixture and the graphene-enhanced coal tar pitch, the use temperature of the liquid coal tar pitch is 170° C., the wet mixing time is 30 min, and the temperature of the paste out of the pot is 160° C.; S6: Place the 160°C paste into a mold for molding. After demoulding, the raw product is transported to a water pool for cooling for 3 hours; S7: sending the raw product into a ring roasting furnace for heat treatment, the highest heat treatment temperature is 950°C, the roasting curve is: room temperature-250°C, heating rate 1°C / h; 251-600°C, heating rate 0.4°C / h; 601-950°C, heating rate 1.5°C / h, the furnace temperature is not higher than 300°C; S8: After cleaning the calcined product, send it to the internal graphitization furnace for graphitization treatment. The graphitization power supply time is 36 hours, and the power supply per ton of calcined product is 3100kWh; S9: Perform machining according to product specifications and drawing requirements.

[0036] Example 7 S1: crushing, screening and grinding graphite and calcined petroleum coke to obtain pellets; S2: 1.5 parts by weight of graphene powder having less than 10 carbon atomic layers and 10 parts by weight of deionized water are mixed with 0.1 parts by weight of cellulose and stirred at high speed to obtain an aqueous graphene slurry.

[0037] S3: adding graphene aqueous slurry to liquid coal tar, wherein the graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar, and mixing the graphene aqueous slurry with the liquid coal tar by mechanical stirring, and volatilizing the aqueous solvent in the graphene aqueous slurry by keeping the liquid coal tar at a constant temperature of 160-170° C., thereby obtaining graphene-enhanced coal tar with good dispersibility; S4: Prepare the solid mixture according to the particle size and proportion, wherein the solid mixture includes the following components by mass percentage: 75% calcined petroleum coke and 25% graphite powder. The prepared solid mixture is transported to the dry material electric heating box for heating and mixing, the dry mixing time is 20 minutes, and the final dry mixing temperature is 180°C; S5: conveying the heated and mixed solid mixture obtained in S4 to a kneading pot, adding the graphene-enhanced coal tar pitch prepared in S2 for wet mixing, wherein the graphene-enhanced coal tar pitch accounts for 20% of the total mass of the solid mixture and the graphene-enhanced coal tar pitch, the use temperature of the liquid coal tar pitch is 180° C., the wet mixing time is 50 min, and the temperature of the paste out of the pot is 180° C.; S6: The paste is sent to a cooler to cool to 140°C and then put into a mold for molding. After demolding, the raw product is sent to a water pool for cooling for 3 hours; S7: sending the raw product into a ring roasting furnace for heat treatment, the highest heat treatment temperature is 950°C, the roasting curve is: room temperature-250°C, heating rate 1°C / h; 251-600°C, heating rate 0.6°C / h; 601-950°C, heating rate 1.5°C / h, the furnace temperature is not higher than 300°C; S8: After cleaning the calcined product, send it to the internal graphitization furnace for graphitization treatment. The graphitization power supply time is 36 hours, and the power supply per ton of calcined product is 3100kWh; S9: Perform machining according to product specifications and drawing requirements.

[0038] Example 8 S1: crushing, screening and grinding graphite and calcined petroleum coke to obtain pellets; S2: 1 part by weight of graphene powder having less than 10 carbon atomic layers and 10 parts by weight of deionized water are mixed with 0.1 parts by weight of cellulose, and then stirred at high speed to obtain an aqueous graphene slurry.

[0039] S3: Add the graphene aqueous slurry into the liquid coal tar pitch. The graphene in the graphene aqueous slurry accounts for 0.05% of the total mass of the graphene aqueous slurry and the liquid coal tar pitch. Mix them evenly with the liquid coal tar pitch through mechanical stirring. By keeping the liquid coal tar pitch at a constant temperature of 160 - 170 °C, volatilize the aqueous solvent in the graphene aqueous slurry to obtain a graphene-reinforced coal tar pitch with good dispersibility. S4: Charge the solid mixture according to the particle size and proportion. The solid mixture includes the following components by mass percentage: calcined petroleum coke 75% and graphite fines 25%. Convey the prepared solid mixture to a dry material electric heating box for heating and mixing. The dry mixing time is 35 min and the final dry mixing temperature is 140 °C. S5: Convey the heated and mixed solid mixture obtained in S4 to a kneading pan, and add the graphene-reinforced coal tar pitch prepared in S2 for wet mixing. The graphene-reinforced coal tar pitch accounts for 20% of the total mass of the solid mixture and the graphene-reinforced coal tar pitch. The use temperature of the graphene-reinforced coal tar pitch is 170 °C. The wet mixing time is 40 min and the temperature of the discharged paste is 170 °C. S6: Feed the paste into a cooling machine to cool it to 140 °C and then into a mold for forming. After demolding, convey the green product to a water tank for cooling for 3 h. S7: Feed the green product into an annular roasting furnace for heat treatment. The highest heat treatment temperature is 950 °C. The roasting curve is as follows: from room temperature to 250 °C, the heating rate is 1 °C / h; from 251 to 600 °C, the heating rate is 0.5 °C / h; from 601 to 950 °C, the heating rate is 1.5 °C / h, and the discharging temperature is not higher than 300 °C. S8: Clean the roasted product and then feed it into an internal series graphitization furnace for graphitization treatment. The graphitization power-on time is 36 h, and the power consumption per ton of roasted product is 3100 kWh. S9: Perform machining according to the product specifications and drawing requirements.

[0040] Example 9 S1: Crush, screen, and grind graphite fines and calcined petroleum coke respectively to obtain granular materials. S2: Mix 1 part by weight of graphene powder with less than 10 carbon atom layers and 10 parts by weight of deionized water, and prepare a graphene aqueous slurry through high-speed mechanical stirring.

[0041] S3: Add the graphene aqueous slurry into the liquid coal tar pitch. The graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar pitch. Mix them evenly with the liquid coal tar pitch through mechanical stirring. By keeping the liquid coal tar pitch at a constant temperature of 160 - 170 °C, volatilize the aqueous solvent in the graphene aqueous slurry to obtain a graphene-reinforced coal tar pitch with good dispersibility. S4: Prepare the solid mixture according to the particle size and proportion, wherein the solid mixture includes the following components by mass percentage: 75% calcined petroleum coke and 25% graphite powder. Transport the prepared solid mixture to the dry material electric heating box for heating and mixing, the dry mixing time is 35 minutes, and the final dry mixing temperature is 140°C; S5: conveying the heated mixed solid mixture obtained in S4 to a kneading pot, adding the graphene-enhanced coal tar pitch prepared in S2 for wet mixing, wherein the graphene-enhanced coal tar pitch accounts for 20% of the total mass of the solid mixture and the graphene-enhanced coal tar pitch, the use temperature of the graphene-enhanced coal tar pitch is 170° C., the wet mixing time is 40 min, and the temperature of the paste out of the pot is 170° C.; S6: The paste is sent to a cooler to cool to 140°C and then put into a mold for molding. After demolding, the raw product is sent to a water pool for cooling for 3 hours; S7: sending the raw product into a ring roasting furnace for heat treatment, the highest heat treatment temperature is 950°C, the roasting curve is: room temperature-250°C, heating rate 1°C / h; 251-600°C, heating rate 0.5°C / h; 601-950°C, heating rate 1.5°C / h, the furnace temperature is not higher than 300°C; S8: After cleaning the calcined product, send it to the internal graphitization furnace for graphitization treatment. The graphitization power supply time is 36 hours, and the power supply per ton of calcined product is 3100kWh; S9: Perform machining according to product specifications and drawing requirements.

[0042] Comparative Example 1 S1: crushing, screening and grinding graphite and calcined petroleum coke to obtain pellets; S2: 1 part by weight of graphene powder having less than 10 carbon atomic layers and 10 parts by weight of deionized water are mixed with 0.1 parts by weight of cellulose, and then stirred at high speed to obtain an aqueous graphene slurry.

[0043] S3: adding graphene aqueous slurry to liquid coal tar, wherein the graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar, and mixing the graphene aqueous slurry with the liquid coal tar by mechanical stirring, and volatilizing the aqueous solvent in the graphene aqueous slurry by keeping the liquid coal tar at a constant temperature of 160-170° C., thereby obtaining graphene-enhanced coal tar with good dispersibility; S4: Prepare the solid mixture according to the particle size and proportion, wherein the solid mixture includes the following components by mass percentage: 50% calcined petroleum coke and 50% graphite powder. Transport the prepared solid mixture to the dry material electric heating box for heating and mixing, the dry mixing time is 35 minutes, and the final dry mixing temperature is 140°C; S5: Convey the heated and mixed solid mixture obtained in S4 to the kneading pot, add the graphene-reinforced coal pitch prepared in S2 for wet mixing. The graphene-reinforced coal pitch accounts for 20% of the total mass of the solid mixture and the graphene-reinforced coal pitch. The use temperature of the graphene-reinforced coal pitch is 170°C, the wet mixing time is 40 min, and the temperature of the discharged paste is 170°C. S6: Feed the paste into a cooling machine to cool it to 140°C and then mold it. After demolding, the green product is conveyed to a water tank for cooling for 3 h. S7: Feed the green product into an annular roasting furnace for heat treatment. The maximum heat treatment temperature is 950°C, and the roasting curve is as follows: room temperature - 250°C, heating rate 1°C / h; 251 - 600°C, heating rate 0.5°C / h; 601 - 950°C, heating rate 1.5°C / h. The discharging temperature is not higher than 300°C. S8: Clean the roasted product and then feed it into an internal-series graphitization furnace for graphitization treatment. The graphitization power-on time is 36 h, and the power consumption per ton of roasted product is 3100 kWh. S9: Perform machining according to the product specifications and drawing requirements.

[0044] Comparative Example 2 S1: Crush, screen, and grind graphite fragments and calcined petroleum coke respectively to obtain granular materials. S2: Weigh the solid mixture according to the particle size and proportion. The solid mixture includes the following components by mass percentage: 75% calcined petroleum coke and 25% graphite fragments. Convey the weighed solid mixture to a dry material electric heating box for heating and mixing. The dry mixing time is 35 min, and the final dry mixing temperature is 140°C. S3: Convey the heated and mixed solid mixture obtained in S2 to the kneading pot, add liquid coal pitch for wet mixing. The liquid coal pitch accounts for 20% of the total mass of the solid mixture and the liquid coal pitch. The use temperature of the liquid coal pitch is 170°C, the wet mixing time is 40 min, and the temperature of the discharged paste is 170°C. S4: Feed the paste into a cooling machine to cool it to 140°C and then mold it. After demolding, the green product is conveyed to a water tank for cooling for 3 h. S5: Feed the green product into an annular roasting furnace for heat treatment. The maximum heat treatment temperature is 950°C, and the roasting curve is as follows: room temperature - 250°C, heating rate 1°C / h; 251 - 600°C, heating rate 0.5°C / h; 601 - 950°C, heating rate 1.5°C / h. The discharging temperature is not higher than 300°C. S6: Clean the roasted product and then feed it into an internal-series graphitization furnace for graphitization treatment. The graphitization power-on time is 36 h, and the power consumption per ton of roasted product is 3100 kWh. S7: Perform machining according to the product specifications and drawing requirements.

[0045] Comparative Example 3 S1: Crush, screen, and grind graphite fragments and calcined petroleum coke respectively to obtain granular materials; S2: Under the condition of adding 0.1 part by weight of cellulose, mix 1 part by weight of graphene powder with less than 10 carbon atom layers and 10 parts by weight of deionized water, and prepare graphene aqueous slurry through high-speed mechanical stirring.

[0046] S3: Add the graphene aqueous slurry to liquid coal tar pitch. The graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and liquid coal tar pitch. Mix it evenly with liquid coal tar pitch through mechanical stirring. By keeping the liquid coal tar pitch at a constant temperature of 160 - 170 °C, volatilize the aqueous solvent in the graphene aqueous slurry to obtain graphene-reinforced coal tar pitch with good dispersibility; S4: Weigh the solid mixture according to the particle size and proportion. The solid mixture includes the following components by mass percentage: 75% of calcined petroleum coke and 25% of graphite fragments. Convey the prepared solid mixture to a dry material electric heating box for heating and mixing. The dry mixing time is 35 min, and the final dry mixing temperature is 140 °C; S5: Convey the heated and mixed solid mixture obtained in S4 to a kneading pot, and add the graphene-reinforced coal tar pitch prepared in S2 for wet mixing. The graphene-reinforced coal tar pitch accounts for 30% of the total mass of the solid mixture and the graphene-reinforced coal tar pitch. The use temperature of the graphene-reinforced coal is 170 °C, the wet mixing time is 40 min, and the temperature of the discharged paste is 170 °C; S6: Feed the paste into a cooling machine to cool it to 140 °C, then put it into a mold for forming. After demolding, convey the green product to a water tank for cooling for 3 h; S7: Feed the green product into a ring-type roasting furnace for heat treatment. The highest heat treatment temperature is 950 °C. The roasting curve is: room temperature - 250 °C, heating rate 1 °C / h; 251 - 600 °C, heating rate 0.5 °C / h; 601 - 950 °C, heating rate 1.5 °C / h. The discharging temperature is not higher than 300 °C; S8: Clean the roasted product and then send it into an internal-series graphitization furnace for graphitization treatment. The graphitization power-on time is 36 h, and the power consumption per ton of roasted product is 3100 kWh; S9: Carry out mechanical processing according to the product specifications and drawing requirements.

[0047] Comparative Example 4 S1: Crush, screen, and grind graphite fragments and calcined petroleum coke respectively to obtain granular materials; S2: Weigh the solid mixture according to the particle size and proportion. The solid mixture includes the following components by mass percentage: 75% of calcined petroleum coke and 25% of graphite fragments. Convey the prepared solid mixture to a dry material electric heating box for heating and mixing. The dry mixing time is 35 min, and the final dry mixing temperature is 140 °C; S3: Convey the heated and mixed solid mixture obtained in S2 to the kneading pot, and wet-mix graphene, cellulose, and liquid coal tar pitch. Graphene accounts for 0.1% of the mass of the solid mixture, cellulose accounts for 0.01% of the mass of the solid mixture, and liquid coal tar pitch accounts for 20% of the total mass of the solid mixture, graphene, cellulose, and liquid coal tar pitch. The use temperature of liquid coal tar pitch is 170°C, the wet-mixing time is 40 min, and the temperature of the discharged paste is 170°C; S4: Feed the paste into a cooling machine to cool it to 140°C and then into a mold for forming. After demolding, the green product is conveyed to a water tank for cooling for 3 h; S5: Feed the green product into a ring-type roasting furnace for heat treatment. The maximum heat treatment temperature is 950°C, and the roasting curve is: room temperature - 250°C, heating rate 1°C / h; 251 - 600°C, heating rate 0.5°C / h; 601 - 950°C, heating rate 1.5°C / h, and the discharging temperature is not higher than 300°C; S6: Clean the roasted product and then feed it into an internal-series graphitization furnace for graphitization treatment. The graphitization power-on time is 36 h, and the power consumption per ton of roasted product is 3100 kWh; S7: Perform machining according to product specifications and drawing requirements.

[0048] Comparative Example 5 S1: Crush, screen, and grind graphite fragments and calcined petroleum coke respectively to obtain granular materials; S2: Weigh the solid mixture according to particle size and proportion. The solid mixture includes the following components by mass percentage: 75% calcined petroleum coke and 25% graphite fragments. Convey the prepared solid mixture, graphene, and cellulose to a dry material electric heating box for heating and mixing. Graphene accounts for 0.1% of the mass of the solid mixture, cellulose accounts for 0.01% of the mass of the solid mixture, the dry-mixing time is 35 min, and the final dry-mixing temperature is 140°C; S3: Convey the heated and mixed solid mixture obtained in S2 to the kneading pot, add the liquid coal tar pitch prepared in S2 for wet-mixing. Liquid coal tar pitch accounts for 20% of the total mass of the solid mixture and liquid coal tar pitch in S2. The use temperature of graphene-reinforced coal tar pitch is 170°C, the wet-mixing time is 40 min, and the temperature of the discharged paste is 170°C; S4: Feed the paste into a cooling machine to cool it to 140°C and then into a mold for forming. After demolding, the green product is conveyed to a water tank for cooling for 3 h; S5: Feed the green product into a ring-type roasting furnace for heat treatment. The maximum heat treatment temperature is 950°C, and the roasting curve is: room temperature - 250°C, heating rate 1°C / h; 251 - 600°C, heating rate 0.5°C / h; 601 - 950°C, heating rate 1.5°C / h, and the discharging temperature is not higher than 300°C; S6: After cleaning the calcined products, feed them into an internal series graphitization furnace for graphitization treatment. The graphitization power-on time is 36 h, and the power consumption per ton of calcined products is 3100 kWh. S7: Carry out machining according to product specifications and drawing requirements.

[0049] Effect example Machine-process the materials obtained in Examples 1-9 and Comparative Examples 1-5, and prepare electrodes with a diameter of 1320 mm according to the regulations in the industry standard "Large-sized Graphite Electrodes for Submerged Arc Furnaces" (Standard No. YB / T 4300-2012).

[0050] The indicators of the products obtained in the examples and comparative examples are shown in Table 1.

[0051] Table 1 Electrode detection indicators Note: The industry standard is the indicator requirements for the specifications with a diameter of 1020-1400 mm in the "Large-sized Graphite Electrodes for Submerged Arc Furnaces" (Standard No. YB / T 4300-2012).

[0052] The resistivity is measured according to the regulations of GB / T 24525; The bulk density is measured according to the regulations of GB / T 24528; The flexural strength is measured according to the regulations of GB / T 3074.1; The ash content is measured according to the regulations of GB / T 1429; The elastic modulus is measured according to the regulations of GB / T 3074.2; The coefficient of thermal expansion is measured according to the regulations of GB / T 3074.4; The thermal conductivity is measured according to the regulations of GB / T 8722.

[0053] 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 perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly conductive and thermally conductive carbon electrode, characterized in that, Its raw materials include a solid mixture and graphene-reinforced coal tar pitch; The solid mixture includes components in the following mass percentages: 60 - 90% calcined petroleum coke, 10 - 40% graphite fines; The raw materials of the graphene-reinforced coal tar pitch include liquid coal tar pitch and graphene aqueous slurry; The graphene aqueous slurry consists of water and graphene, and the weight ratio of water to graphene is 10:1 - 1.5; The graphene-reinforced coal tar pitch accounts for 15% - 25% of the total mass of the solid mixture and the graphene-reinforced coal tar pitch; The mass of graphene in the graphene-reinforced coal tar pitch accounts for 0.05% - 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar pitch.

2. The highly conductive and thermally conductive carbon electrode according to claim 1, characterized in that, The graphene aqueous slurry also contains cellulose, and the weight ratio of water, graphene, and cellulose is 10:1 - 1.5:0.05 - 0.

15.

3. A highly conductive and thermally conductive carbon electrode according to claim 1, wherein, The calcined petroleum coke is low-sulfur petroleum coke treated at high temperature, and the mass percentage of sulfur < 0.5%; The coal tar pitch is medium-temperature modified pitch prepared by the Coppus process, and the softening point is 90 - 100°C; The graphene aqueous slurry is an aqueous slurry prepared from graphene powder materials with less than 10 layers; The graphite fines are graphitization waste products generated from electrode carbon products.

4. A highly conductive and thermally conductive carbon electrode according to claim 1, characterized in that, The solid mixture includes components in the following mass percentages: 70 - 80% calcined petroleum coke, 20 - 30% graphite fines; The graphene-reinforced coal tar pitch accounts for 20% - 21% of the total mass of the solid mixture and the graphene-reinforced coal tar pitch.

5. A highly conductive and thermally conductive carbon electrode according to claim 1, wherein The solid mixture includes components in the following mass percentages: 75% calcined petroleum coke, 25% graphite fines; The graphene aqueous slurry also contains cellulose, and the weight ratio of water, graphene, and cellulose is 10:1:0.1; The graphene-reinforced coal tar pitch accounts for 20% of the total mass of the solid mixture and the graphene-reinforced coal tar pitch. The mass of graphene in the graphene aqueous slurry accounts for 0.5% of the total mass of the graphene aqueous slurry and the liquid coal tar pitch.

6. A highly conductive and thermally conductive carbon electrode according to claim 1, characterized in that, The high-conductivity and high-heat-conductivity carbon electrode has a diameter of 1020 mm - 1400 mm.

7. A method for preparing a highly conductive and thermally conductive carbon electrode according to any one of claims 1-5, characterized in that, It includes the following steps: S1: Crush, screen, and grind graphite fines and calcined petroleum coke respectively to obtain granular materials for standby; S2: Mix graphene, water, and cellulose to obtain graphene aqueous slurry for standby; S3: Add the graphene aqueous slurry to the liquid coal tar pitch, stir evenly, heat to 160 - 170°C and keep it constant to volatilize the aqueous solvent in the graphene aqueous slurry to obtain graphene-reinforced coal tar pitch; S4: Weigh the solid mixture according to the particle size and ratio, convey the prepared solid mixture to a dry material electric heating box for heating and mixing, the dry mixing time is 20 - 40 min, and the final dry mixing temperature is 120 - 180°C; S5: Convey the heated and mixed solid mixture obtained in S4 to a kneading pot, add the graphene-reinforced coal tar pitch prepared in S3 for wet mixing, the use temperature of the liquid coal tar pitch is 160 - 170°C, the wet mixing time is 30 - 50 min, and the temperature of the discharged paste is 160 - 180°C; S6: Send the paste to a cooling machine to cool to 130 - 160°C and then mold it. After demolding, the green product is conveyed to a water tank for cooling for 2 - 3 h; S7: Feed the green product into a ring-type roasting furnace for heat treatment. The maximum heat treatment temperature is 800 - 1000 °C, the roasting cycle is 980 - 1450 h, the holding time at the maximum temperature is 48 h - 72 h, and the discharging temperature is from room temperature to 300 °C; S8: After cleaning the roasted product, feed it into an internal series graphitization furnace for graphitization treatment. The graphitization power-on time is 30 - 40 h, and the power consumption per ton of roasted product is 3000 - 3500 kWh; S9: Conduct machining according to product specifications and drawing requirements.

8. The preparation method of the highly conductive and heat-conductive carbon electrode according to claim 7, wherein, The batching of the solid mixture according to particle size and proportion is that the powder with a particle size less than 1 mm accounts for 40 - 50% of the total mass of the solid material, the particle size of 1 - 4 mm accounts for 15 - 25% of the total mass of the solid material, the particle size of 4 - 10 mm accounts for 20 - 30% of the total mass of the solid material, and the particle size of 10 - 16 mm accounts for 5 - 15% of the total mass of the solid material.

9. The preparation method of the highly conductive and thermally conductive carbon electrode according to claim 7, characterized in that, In S6, when feeding into the cooling machine for cooling, evacuate the asphalt fumes in the paste by means of vacuum pumping, and form it by means of variable-frequency vibration and up-and-down pressurization of the mold. After forming, the green body is cooled by passing water in the mold for 50 - 80 min and then demolded.

10. The preparation method of the highly conductive and heat-conductive carbon electrode according to claim 7, characterized in that, The roasting curve in S7 is as follows: room temperature - 250 °C, heating rate 1 - 1.5 °C / h; 251 - 600 °C, heating rate 0.4 - 0.6 °C / h; 601 - 950 °C, heating rate 1 - 1.5 °C / h.

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