CN111018554A - Method for preparing ultrahigh-power graphite electrode by using graphene - Google Patents

Method for preparing ultrahigh-power graphite electrode by using graphene Download PDF

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Publication number
CN111018554A
CN111018554A CN201911153810.XA CN201911153810A CN111018554A CN 111018554 A CN111018554 A CN 111018554A CN 201911153810 A CN201911153810 A CN 201911153810A CN 111018554 A CN111018554 A CN 111018554A
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temperature
equal
graphene
ultrahigh
power graphite
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魏健
张锦俊
闵洁
张培林
庞中海
武建军
刘伟凯
纪永良
徐保国
吕星薄
雷涛
霍有
张彦举
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Datong Xincheng New Material Co Ltd
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Datong Xincheng New Material Co Ltd
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Abstract

The invention relates to the technical field of electrode preparation, in particular to a method for preparing an ultrahigh-power graphite electrode by utilizing graphene, which takes acicular petroleum coke as aggregate; the high-power graphite is prepared from graphene powder, ultrahigh-power graphite powder, carbon black, carbon fiber and other powder materials, and is subjected to solvent dispersion, high-temperature hot-press molding and high-temperature purification treatment at the maximum temperature of 3200 ℃ to convert the graphene powder, the ultrahigh-power graphite powder, the carbon black, the carbon fiber and other powder materials into microcrystalline artificial graphite. So as to enhance the physical and chemical properties of the high-power graphite electrode. The invention has reasonable raw material selection, scientific preparation process and the like, and the method and the material are used for producing the ultrahigh-power graphite electrode with various physical and chemical properties and high quality. The method is favorable for improving the product percent of pass, makes full use of the characteristics of materials such as graphene, carbon black, carbon fiber and the like, and the medium-temperature coal pitch is easy to graphitize in the graphitization process, so that the physicochemical index of the final product can be fully satisfied.

Description

Method for preparing ultrahigh-power graphite electrode by using graphene
Technical Field
The invention relates to the technical field of electrode preparation, in particular to a method for preparing an ultrahigh-power graphite electrode by utilizing graphene.
Background
The graphite electrode is a conductor which releases electric energy in the form of electric arc in an electric arc furnace to heat and melt furnace burden, and can be divided into ordinary power, high power and ultrahigh power according to the low quality index.
The high-temperature resistant graphite conductive material is prepared by taking petroleum coke and pitch coke as granules and coal pitch as an adhesive through kneading, molding, roasting, graphitizing and machining. The graphite electrode is an important high-temperature conductive material for electric furnace steelmaking, electric energy is input into the electric furnace through the graphite electrode, high temperature generated by electric arc between the end part of the electrode and furnace charge is used as a heat source, the furnace charge is melted for steelmaking, and other electric smelting or electrolysis equipment also commonly use the graphite electrode as the conductive material.
Graphite electrodes are consumed by about 100 million t all over the world in 2000, and graphite electrodes are consumed by about 25 million t in 2000 in China. The graphite electrode has wide application in other industrial departments by utilizing the excellent physical and chemical properties of the graphite electrode, and the industry of producing carbon products taking the graphite electrode as a main variety has become an important component department of the modern raw material industry.
The main indexes for measuring the quality of the graphite electrode are resistivity, volume density, mechanical strength, linear expansion coefficient, elastic modulus and the like, the oxidation resistance and the thermal shock resistance of the graphite electrode in use are related to the indexes, and the machining accuracy and the connection reliability of the product are also important detection items.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a method for preparing an ultrahigh-power graphite electrode by using graphene.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for preparing an ultrahigh-power graphite electrode by using graphene comprises the following steps:
s1, mixing the aggregate and the powder, and then placing the mixture into a ball mill for milling, wherein the milling temperature is 140-;
s2, kneading: adding the adhesive into the mixture in the S1 for mixing and kneading twice to obtain paste, wherein the wet mixing temperature is 150-170 ℃;
s3, molding: cooling the paste kneaded in the S2 to the temperature of 120-130 ℃, pouring the paste into a forming machine, extruding and forming the paste from an outlet of the forming machine by pressure, wherein the tamping pressure of the extrusion forming is 8MPa, the pre-pressing pressure is 20MPa, the pre-pressing time is 4min, the extrusion pressure is 5-7.5MPa, the extrusion speed length is 1800mm and 150S, the outlet temperature of the extrusion forming machine is 110-120 ℃, the forming section temperature of the extruding machine is 155-160 ℃, the deformation zone temperature of the extruding machine is 120-130 ℃, the material chamber temperature of the extruding machine is 120-130 ℃, the plunger head temperature of the extruding machine is 140-150 ℃, and the volume density of the formed green body is more than or equal to 1.78g/cm3
S4, primary roasting: placing the molded green body in S3 into a roasting furnace for roasting to obtain a first green body;
s5, dipping, namely preheating the first blank in the S4, dipping, vacuumizing a dipping tank, pressurizing to 1.5Mpa, maintaining the pressure at 1.35Mpa for 50-60 minutes, and dipping;
s6, secondary roasting: roasting the impregnated blank in S5 for 650 hours at the temperature of 800-900 ℃;
s7, graphitizing: graphitizing the green body after roasting in S6 for 500 hours at 2800-3000 ℃;
and S8, electrifying the graphitized blank in the S7, heating to the temperature of 700 ℃ and 850 ℃ under the condition of air isolation, keeping the current intensity at 15A for 8-10 hours, and obtaining the graphite electrode.
Further, the aggregate comprises acicular petroleum coke; the powder material comprises graphene powder, ultrahigh-power graphite powder, carbon black and carbon fiber; the binder adopts medium-temperature coal pitch; the impregnant adopts impregnating asphalt.
Furthermore, the true density of the acicular petroleum coke is more than or equal to 2.13g/cm3Ash content is less than or equal to 0.20 percent, volatile matter is less than or equal to 0.25 percent, and sulfur content is less than or equal to 0.30 percent;
the particle size of the graphene powder is 3-6 mu m, the purity is 99.9%, the tensile modulus is less than or equal to 1.01TPa, and the ultimate strength is less than or equal to 116 Gpa; the particle size of the ultrahigh-power graphite powder is 5-10 mu m, and the volume density is more than or equal to 1.80g/cm3The resistivity is less than or equal to 8 mu omega m, the breaking strength is more than or equal to 30Mpa, and the compressive strength is more than or equal to 60 Mpa; the purity of the carbon black is 99%, and the particle size is 6-12 mu m; the particle size of the carbon fiber is 7-14 mu m, the tensile strength is more than or equal to 7.0Gpa, and the density is 2.10g/cm3The resistivity is less than or equal to 35 mu omega cm;
the softening point of the medium-temperature coal pitch is 90-105 ℃, the coking value is more than or equal to 51 percent, and the ash content is less than or equal to 0.3 percent;
the softening point of the dipping asphalt is 90-110 ℃, the coking value is more than or equal to 52 percent, and the quinoline insoluble is less than or equal to 0.25 percent.
Further, the weight ratio of the graphene powder, the ultrahigh-power graphite powder, the carbon black and the carbon fiber is 20:35:25: 20.
Further, the weight ratio of the aggregate to the powder is 65:35-60: 40;
the weight ratio of the mixture in the S1 to the medium-temperature coal pitch in the binder is 70:30-75:25, preferably 72-70: 28-30.
Further, the needle petroleum coke has the particle size range and content as follows:
25wt% of particle size 60-40 μm;
20wt% of particle size 40-20 μm;
30wt% of particle size 20-10 μm;
15wt% of particle size 10-1.0 μm;
the particle diameter is 1.0-0.5 μm 10 wt%.
Further, the weight of the medium-temperature coal pitch added for the first time in S2 is 75-85% of the total medium-temperature coal pitch, the time of the first wet mixing is 20-25 minutes, the weight of the medium-temperature coal pitch added for the second time is 15-25% of the total medium-temperature coal pitch, and the time of the second wet mixing is 20-25 minutes.
Further, the S4 temperature increasing process: at the normal temperature of-150 ℃, the heating rate is 2 +/-1 ℃/h; the heating rate is 2 +/-1 ℃/h at the temperature of 150-; the heating rate is 2.5 +/-1 ℃/h at the temperature of 350-550 ℃; the heating rate is 4 +/-1 ℃/h at the temperature of 550 ℃ and 750 ℃; the heating rate is 5 +/-1 ℃/h at the temperature of 750 plus or minus 950 ℃; the heating rate is 2 +/-1 ℃/h at 950-1150 ℃; the temperature rise rate is 2 +/-1 ℃/h at 1150-1250 ℃; keeping the temperature for 24 hours at 1250 ℃.
Further, before the S5 impregnation, the impregnant is subjected to moisture removal and impurity removal treatment, the impregnation pitch is heated to 320 ℃ of 220-.
Further, the preheating temperature of the first blank body during the impregnation of S5 is 360-380 ℃, and the weight gain rate is 13-14%.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a method for preparing an ultrahigh-power graphite electrode by utilizing graphene, which takes acicular petroleum coke as aggregate; the high-power graphite is prepared from graphene powder, ultrahigh-power graphite powder, carbon black, carbon fiber and other powder materials, and is subjected to solvent dispersion, high-temperature hot-press molding and high-temperature purification treatment at the maximum temperature of 3200 ℃ to convert the graphene powder, the ultrahigh-power graphite powder, the carbon black, the carbon fiber and other powder materials into microcrystalline artificial graphite. So as to enhance the physical and chemical properties of the high-power graphite electrode. The raw materials of the inventionReasonable selection, scientific preparation process and the like, and the method and the material are used for producing the ultrahigh-power graphite electrode with various physical and chemical properties and high quality. The method is favorable for improving the product percent of pass, makes full use of the characteristics of materials such as graphene, carbon black, carbon fiber and the like, and the medium-temperature coal pitch is easy to graphitize in the graphitization process, so that the physicochemical index of the final product can be fully satisfied. The volume density of the prepared ultrahigh-power graphite electrode is more than or equal to 1.75g/cm3The resistivity is less than or equal to 5.5 mu omega m, the elastic modulus is 7.0-9.5GPa, the breaking strength is 7-13MPa, and the thermal expansion coefficient is 0.2-0.6 (10)-60.30 percent of ash content and thermal conductivity of 210-290/W (m.DEG C)-1
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
A method for preparing an ultrahigh-power graphite electrode by using graphene comprises the following steps:
s1, mixing the aggregate and the powder, and then placing the mixture into a ball mill for milling, wherein the milling temperature is 140-; the aggregate comprises acicular petroleum coke; the powder material comprises graphene powder, ultrahigh-power graphite powder, carbon black and carbon fiber; the weight ratio of the graphene powder to the ultrahigh-power graphite powder to the carbon black to the carbon fiber is 20:35:25: 20; the weight ratio of the aggregate to the powder is 65:35-60: 40;
s2, kneading: adding the adhesive into the mixture in the S1 for mixing and kneading twice to obtain paste, wherein the wet mixing temperature is 150-170 ℃; the binder adopts medium-temperature coal pitch; the weight ratio of the mixture to the medium-temperature coal pitch in the binder is 70:30-75:25, preferably 72-70: 28-30; the weight of the medium-temperature coal pitch added for the first time is 75-85% of the total medium-temperature coal pitch, the time of the wet mixing for the first time is 20-25 minutes, the weight of the medium-temperature coal pitch added for the second time is 15-25% of the total medium-temperature coal pitch, and the time of the wet mixing for the second time is 20-25 minutes;
wherein the acicular petroleum coke has the particle size range and the content as follows:
25wt% of particle size 60-40 μm;
20wt% of particle size 40-20 μm;
30wt% of particle size 20-10 μm;
15wt% of particle size 10-1.0 μm;
10wt% of particle size 1.0-0.5 μm;
s3, molding: cooling the paste kneaded in the S2 to the temperature of 120-130 ℃, pouring the paste into a forming machine, extruding and forming the paste from an outlet of the forming machine by pressure, wherein the tamping pressure of the extrusion forming is 8MPa, the pre-pressing pressure is 20MPa, the pre-pressing time is 4min, the extrusion pressure is 5-7.5MPa, the extrusion speed length is 1800mm and 150S, the outlet temperature of the extrusion forming machine is 110-120 ℃, the forming section temperature of the extruding machine is 155-160 ℃, the deformation zone temperature of the extruding machine is 120-130 ℃, the material chamber temperature of the extruding machine is 120-130 ℃, the plunger head temperature of the extruding machine is 140-150 ℃, and the volume density of the formed green body is more than or equal to 1.78g/cm3
S4, primary roasting: placing the molded green body in S3 into a roasting furnace for roasting to obtain a first green body; the temperature rising procedure is as follows: at the normal temperature of-150 ℃, the heating rate is 2 +/-1 ℃/h; the heating rate is 2 +/-1 ℃/h at the temperature of 150-; the heating rate is 2.5 +/-1 ℃/h at the temperature of 350-550 ℃; the heating rate is 4 +/-1 ℃/h at the temperature of 550 ℃ and 750 ℃; the heating rate is 5 +/-1 ℃/h at the temperature of 750 plus or minus 950 ℃; the heating rate is 2 +/-1 ℃/h at 950-1150 ℃; the temperature rise rate is 2 +/-1 ℃/h at 1150-1250 ℃; keeping the temperature for 24 hours at 1250 DEG C
S5, dipping, namely preheating the first blank in the S4 and then dipping, wherein the preheating temperature is 360-380 ℃, vacuumizing the dipping tank and pressurizing to 1.5Mpa, and keeping the pressure at 1.35Mpa for 50-60 minutes for dipping; the impregnant adopts impregnating asphalt during impregnation; before impregnation, the impregnant is subjected to moisture removal and impurity removal treatment, the impregnated asphalt is heated to 320 ℃ of 220-; the weight gain of the first blank after impregnation is 13-14%;
s6, secondary roasting: roasting the impregnated blank in S5 for 650 hours at the temperature of 800-900 ℃;
s7, graphitizing: graphitizing the green body after roasting in S6 for 500 hours at 2800-3000 ℃;
and S8, electrifying the graphitized blank in the S7, heating to the temperature of 700 ℃ and 850 ℃ under the condition of air isolation, keeping the current intensity at 15A for 8-10 hours, and obtaining the graphite electrode.
In this example, the true density of acicular petroleum coke is 2.13g/cm or more3Ash content is less than or equal to 0.20 percent, volatile matter is less than or equal to 0.25 percent, and sulfur content is less than or equal to 0.30 percent; the particle size of the graphene powder is 3-6 mu m, the purity is 99.9%, the tensile modulus is less than or equal to 1.01TPa, and the ultimate strength is less than or equal to 116 Gpa; the particle size of the ultrahigh-power graphite powder is 5-10 mu m, and the volume density is more than or equal to 1.80g/cm3The resistivity is less than or equal to 8 mu omega m, the breaking strength is more than or equal to 30Mpa, and the compressive strength is more than or equal to 60 Mpa; the purity of the carbon black is 99%, and the particle size is 6-12 mu m; the particle size of the carbon fiber is 7-14 mu m, the tensile strength is more than or equal to 7.0Gpa, and the density is 2.10g/cm3The resistivity is less than or equal to 35 mu omega cm; the softening point of the medium-temperature coal pitch is 90-105 ℃, the coking value is more than or equal to 51 percent, and the ash content is less than or equal to 0.3 percent; the softening point of the dipping asphalt is 90-110 ℃, the coking value is more than or equal to 52 percent, and the quinoline insoluble is less than or equal to 0.25 percent.
In the preparation process of the graphite product, the formula has great influence on the performance parameters of the graphite product, particularly on the volume density, the porosity and the thermal expansion coefficient. Generally, the product obtained by adopting a finer particle formula is large in volume density, small in porosity and elegant and high in fracture resistance and compression strength, needle petroleum coke with high isotropy, high density, high strength, low porosity and small pores is selected during material selection, and an ultrafine grinding and small particle formula is adopted during material preparation, so that the maximum material diameter of the aggregate is less than 0.5 mu m. In this particle size range, the distribution of particle sizes of the particles directly affects the manner of stacking of the particles, and the more densely the particles are stacked, the larger the volume density and the smaller the porosity of the graphite product, and in this particle size range, the average particle size doubles and the thermal expansion rate decreases by about 7% while the particle size is maintained.
The aggregate particles with different particle diameters are closely stacked, the volume density, the porosity, the mechanical strength and the thermal expansion coefficient of the graphite product can reach a very good balance, and the prepared graphite product has large volume density, small porosity and small thermal expansion coefficient.
The molding method is characterized in that the molding method is carried out in a mode of extrusion, so that the dosage of the medium-temperature asphalt as the binder has strict proportioning requirements, the dosage of the binder has a direct relation with the surface area of the aggregate, the smaller the particle size of the aggregate is, the larger the surface area is, the more the binder is, but the too much binder is used, so that the compaction is not easy to occur during molding, the volume density of the product is smaller, and the product is easy to deform after demolding. The proportion of the binder and the aggregate is 70:75-30:25%, after the aggregate and the binder are kneaded, the obtained paste is basically not in the form of lumps, most of the paste is in the form of loose particles or a few small lumps are poured on a material airing table, and a molded product with high volume density is obtained after molding. The smaller the particles of the aggregate, the larger the surface area, the more difficult it is to mix uniformly in wet mixing, the longer the wet mixing time, and the more energy consumption. In the wet mixing process, the binder is added into the dry-mixed aggregate for mixing and kneading twice, the binder accounting for 70-80% of the total binder is added for the first time to be bonded with the aggregate, the mixture has low viscosity due to small addition amount, and can be uniformly mixed and kneaded in a short time under the action of stirring force under the same condition, the particle size of the raw material particles is uniformly increased after the first wet mixing, the specific surface area of the raw material particles is reduced, and the rest binder is added, so that the aggregate and the binder can be uniformly mixed in a short time. The medium-temperature asphalt serving as the binder is added twice, so that the wet mixing time can be shortened, the energy consumption is reduced, the paste can be uniformly kneaded, the paste with good plasticity is obtained, and the yield and the physical property of the formed green body can be improved.
The purpose of roasting is to carbonize the binder pitch, form coke grids among the aggregate particles, and firmly bond the aggregates with different granularities into a whole. When the small particle formula is used for preparing the carbon material, the probability of cracks in the subsequent heat treatment process is high, and the yield is possibly low.
The properties of the impregnated asphalt have important influence on the impregnation effect, and are mainly reflected on asphalt viscosity, quinoline insoluble content and coking value. The higher the coking value is, the larger the bulk density and mechanical strength of the roasted product is, and the coking value is increased along with the increase of the softening point, so that the coal pitch with higher softening point is adopted as the binder, which is beneficial to improving the bulk density and mechanical strength of the product material, but the higher the softening point of the impregnated pitch is, the higher the relative viscosity is, the more the relative viscosity is, the green removing viscosity which is difficult to permeate into the pores of the impregnated product is influenced by the property of the impregnated pitch, and is inversely proportional to the heating temperature. In order to improve the dipping effect, the invention firstly selects the asphalt with the softening point of 83-86 ℃ and the coking value of more than or equal to 48 percent, and secondly heats the dipping asphalt to reduce the viscosity of the dipping asphalt. Generally, after the temperature exceeds 200 ℃, the light component in the asphalt begins to volatilize, 200-400 ℃ is the volatilization stage of the light component in the impregnated asphalt, the molecular weight of the light component volatilized in the impregnated asphalt gradually increases along with the increase of the temperature, the volatilized gas enters the gas in the gas of the impregnated product to hinder the permeation of the asphalt, so in the prior art, the impregnation is started after the impregnated asphalt is heated to 160-180 ℃, the temperature for heating the impregnated asphalt does not exceed 200 ℃, but because the preheating temperature of the carbonaceous product to be impregnated is generally between 300-400 ℃, the light component still volatilizes from the impregnated asphalt in the impregnated carbonaceous product during the impregnation process, the permeation of the impregnated asphalt is hindered, a plurality of gas pores are formed in the impregnated product, and before the impregnation, the impregnated asphalt is heated to 220-320 ℃, the dipping pitch is preferably heated to 260 ℃ of 220-. During impregnation, the carbonaceous product to be impregnated is firstly vacuumized, the purpose of vacuumization is to discharge gas in the pores of the carbonaceous product to be impregnated so as to be beneficial to the permeation of the impregnating pitch, and after the impregnating pitch is added, the impregnating pitch is easy to permeate into the pores of the carbonaceous product to be impregnated under the action of pressure, so that the weight gain rate is ensured; quinoline insoluble substances in the coal pitch are tiny particles, and the quinoline insoluble substances form a layer of film on the surface of the porous material during impregnation to hinder the impregnant from permeating the porous material, so the impregnation pitch with the quinoline insoluble substances of less than or equal to 0.25 percent is selected. And (4) carrying out moisture removal and impurity removal treatment on the impregnated asphalt.
Although only the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art, and all changes are encompassed in the scope of the present invention.

Claims (10)

1. A method for preparing an ultrahigh-power graphite electrode by using graphene is characterized by comprising the following steps:
s1, mixing the aggregate and the powder, and then placing the mixture into a ball mill for milling, wherein the milling temperature is 140-;
s2, kneading: adding the adhesive into the mixture in the S1 for mixing and kneading twice to obtain paste, wherein the wet mixing temperature is 150-170 ℃;
s3, molding: cooling the paste kneaded in the S2 to the temperature of 120-130 ℃, pouring the paste into a forming machine, extruding and forming the paste from an outlet of the forming machine by pressure, wherein the tamping pressure of the extrusion forming is 8MPa, the pre-pressing pressure is 20MPa, the pre-pressing time is 4min, the extrusion pressure is 5-7.5MPa, the extrusion speed length is 1800mm and 150S, the outlet temperature of the extrusion forming machine is 110-120 ℃, the forming section temperature of the extrusion forming machine is 155-160 ℃, the deformation zone temperature of the extrusion forming machine is 120-130 ℃,the temperature of the material chamber of the extruder is 120 ℃ plus 130 ℃, the temperature of the plunger head of the extruder is 140 ℃ plus 150 ℃, and the volume density of the molded green body is more than or equal to 1.78g/cm3
S4, primary roasting: placing the molded green body in S3 into a roasting furnace for roasting to obtain a first green body;
s5, dipping, namely preheating the first blank in the S4, dipping, vacuumizing a dipping tank, pressurizing to 1.5Mpa, maintaining the pressure at 1.35Mpa for 50-60 minutes, and dipping;
s6, secondary roasting: roasting the impregnated blank in S5 for 650 hours at the temperature of 800-900 ℃;
s7, graphitizing: graphitizing the green body after roasting in S6 for 500 hours at 2800-3000 ℃;
and S8, electrifying the graphitized blank in the S7, heating to the temperature of 700 ℃ and 850 ℃ under the condition of air isolation, keeping the current intensity at 15A for 8-10 hours, and obtaining the graphite electrode.
2. The method for preparing the ultrahigh-power graphite electrode by using the graphene as claimed in claim 1, wherein the method comprises the following steps: the aggregate comprises acicular petroleum coke; the powder material comprises graphene powder, ultrahigh-power graphite powder, carbon black and carbon fiber; the binder adopts medium-temperature coal pitch; the impregnant adopts impregnating asphalt.
3. The method for preparing the ultra-high power graphite electrode by using the graphene as claimed in claim 2, wherein the method comprises the following steps: the true density of the acicular petroleum coke is more than or equal to 2.13g/cm3Ash content is less than or equal to 0.20 percent, volatile matter is less than or equal to 0.25 percent, and sulfur content is less than or equal to 0.30 percent;
the particle size of the graphene powder is 3-6 mu m, the purity is 99.9%, the tensile modulus is less than or equal to 1.01TPa, and the ultimate strength is less than or equal to 116 Gpa; the particle size of the ultrahigh-power graphite powder is 5-10 mu m, and the volume density is more than or equal to 1.80g/cm3The resistivity is less than or equal to 8 mu omega m, the breaking strength is more than or equal to 30Mpa, and the compressive strength is more than or equal to 60 Mpa; the purity of the carbon black is 99%, and the particle size is 6-12 mu m; the particle size of the carbon fiber is 7-14 mu m, the tensile strength is more than or equal to 7.0Gpa, and the density is 2.10g/cm3The resistivity is less than or equal to 35 mu omega cm;
the softening point of the medium-temperature coal pitch is 90-105 ℃, the coking value is more than or equal to 51 percent, and the ash content is less than or equal to 0.3 percent;
the softening point of the dipping asphalt is 90-110 ℃, the coking value is more than or equal to 52 percent, and the quinoline insoluble is less than or equal to 0.25 percent.
4. The method for preparing the ultra-high power graphite electrode by using the graphene as claimed in claim 2, wherein the method comprises the following steps: the weight ratio of the graphene powder to the ultrahigh-power graphite powder to the carbon black to the carbon fiber is 20:35:25: 20.
5. The method for preparing the ultrahigh-power graphite electrode by using the graphene as claimed in claim 1, wherein the method comprises the following steps: the weight ratio of the aggregate to the powder is 65:35-60: 40;
the weight ratio of the mixture in the S1 to the medium-temperature coal pitch in the binder is 70:30-75: 25.
6. The method for preparing the ultrahigh-power graphite electrode by using the graphene as claimed in claim 1, wherein the method comprises the following steps: the needle petroleum coke has the particle size range and the content as follows:
25wt% of particle size 60-40 μm;
20wt% of particle size 40-20 μm;
30wt% of particle size 20-10 μm;
15wt% of particle size 10-1.0 μm;
the particle diameter is 1.0-0.5 μm 10 wt%.
7. The method for preparing the ultrahigh-power graphite electrode by using the graphene as claimed in claim 1, wherein the method comprises the following steps: s2, the weight of the medium-temperature coal tar pitch added for the first time is 75-85% of the total medium-temperature coal tar pitch, the time of the first wet mixing is 20-25 minutes, the weight of the medium-temperature coal tar pitch added for the second time is 15-25% of the total medium-temperature coal tar pitch, and the time of the second wet mixing is 20-25 minutes.
8. The method for preparing the ultra-high power graphite electrode by using the graphene as claimed in claim 1, wherein the S4 temperature rising procedure is as follows: at the normal temperature of-150 ℃, the heating rate is 2 +/-1 ℃/h; the heating rate is 2 +/-1 ℃/h at the temperature of 150-; the heating rate is 2.5 +/-1 ℃/h at the temperature of 350-550 ℃; the heating rate is 4 +/-1 ℃/h at the temperature of 550 ℃ and 750 ℃; the heating rate is 5 +/-1 ℃/h at the temperature of 750 plus or minus 950 ℃; the heating rate is 2 +/-1 ℃/h at 950-1150 ℃; the temperature rise rate is 2 +/-1 ℃/h at 1150-1250 ℃; keeping the temperature for 24 hours at 1250 ℃.
9. The method for preparing the ultrahigh-power graphite electrode by using the graphene as claimed in claim 1, wherein the method comprises the following steps: before the S5 impregnation, the impregnant is subjected to moisture removal and impurity removal treatment, the impregnated asphalt is heated to 320 ℃ of 220-.
10. The method for preparing the ultrahigh-power graphite electrode by using the graphene as claimed in claim 1, wherein the method comprises the following steps: the preheating temperature of the first blank body during the S5 impregnation is 360-380 ℃, and the weight gain rate is 13-14%.
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