CN110590363A - A kind of ultra-high power graphite electrode and its manufacturing method - Google Patents

Abstract

The invention discloses an ultra-high-power graphite electrode and a manufacturing method thereof. The raw materials for preparing the ultra-high-power graphite electrode include graphene, needle coke, binder, roasted crushed graphite and graphite crushed. The raw materials are calcined, compounded, Kneading, pressing, primary roasting, impregnation, secondary roasting, graphitization, mechanical processing to finished products. When the ultra-high power graphite electrode of the present invention is produced, graphene powder modification is added, and the graphene powder is dispersed in the graphite electrode green body. When the graphitization process is carried out, the graphene powder can be used as a crystal nucleus to make the surrounding carbon Atoms continue to grow crystals on it to form larger graphite layered crystals, or generate polycrystals, and induce the transformation of surrounding carbon atoms from amorphous to crystalline to generate new graphite layered crystals, thereby greatly The degree of graphitization of the product is greatly improved, the resistivity of the product is reduced, and the flexural strength of the product is improved at the same time.

Description

A kind of ultra-high power graphite electrode and its manufacturing method

technical field

The invention relates to the technical field of electrode manufacturing, in particular to an ultra-high-power graphite electrode and a method for manufacturing the ultra-high-power graphite electrode.

Background technique

Graphite electrodes are mainly made of petroleum coke and needle coke through calcination, batching, kneading, pressing, roasting, graphitization, and machining. Conductors, according to their quality indicators, can be divided into ordinary power graphite electrodes, high power graphite electrodes and ultra-high power graphite electrodes.

With the development of large-scale and ultra-high-power electric furnace steelmaking, the diameter of graphite electrodes is also developing towards large-scale. Patent application 2017103305274 discloses a large-scale high-power graphite electrode, which uses petroleum coke and needle coke as the main raw materials, and uses medium-temperature reformed pitch with high coking value as the binder, which reduces the impregnation and secondary roasting processes, and produces Large size and high power graphite electrodes.

Graphene is one of the materials with the highest strength known at present, and it also has good toughness, and graphene has very good thermal conductivity. The thermal conductivity of pure and defect-free single-layer graphene is as high as 5300W/mK, which is the best thermal conductivity so far. The carbon material with the highest coefficient is higher than single-wall carbon nanotubes and multi-wall carbon nanotubes; and the thermal conductivity of graphene as a carrier can also reach 600W/mK. Using graphene to modify graphite electrodes or graphite electrode joints is one of the means to improve the performance of graphite electrodes. Patent application 2018110227058 discloses a graphite electrode joint containing graphene. Powdered graphene raw materials are added to graphite electrode joints. It can improve the bending resistance of the electrode joint and enhance the oxidation resistance of the electrode joint at high temperature. However, the amount of graphene added for modification is very large, which increases the production cost.

Contents of the invention

In view of the defects in the prior art, one of the purposes of the present invention is to provide a graphene-modified ultra-high power graphite electrode, which can effectively reduce the resistance of the ultra-high power graphite electrode by adding graphene to the raw material of the graphite electrode rate and reduce its thermal expansion coefficient.

Another object of the present invention is to provide a method for preparing the above ultra-high power graphite electrode.

To achieve the above object, the present invention adopts the following schemes:

An ultra-high-power graphite electrode, the preparation raw materials include the following components in weight percentage: 0.3-0.7% of graphene, 65-73% of needle coke, 21-28% of binder, 2-5% of roasted powder and graphite powder 3-7.5%.

Preferably, the particle size composition of the needle coke is as follows: 16-22mm accounts for 12-18%, 6-16mm accounts for 10-15%, 2-6mm accounts for 10-14%, 0.075-0.5mm accounts for 22-33%, 0.075mm or less accounted for 27-42%.

Preferably, the particle size of the roasted powder is 1-2mm.

Preferably, the particle size of the crushed graphite is 1-2 mm.

Preferably, the particle size of the graphene is less than 1mm.

Preferably, the binder is medium temperature asphalt. The coking value of the medium-temperature pitch used is ≥56%, the softening point is 94-99°C, the melting temperature is 108-114°C, the content of toluene insolubles is 28-32%, and the content of quinoline insolubles is 8-12%.

A method for manufacturing the above-mentioned ultra-high power graphite electrode, comprising steps:

(1) Raw material processing: The raw material needle coke is processed into granules and powders of needle coke of various sizes through calcination, secondary crushing, grinding and screening; weigh graphene, graphite crushed, roasted crushed, binder And granular materials and powder materials of needle coke of various sizes;

(2) Kneading: Graphene is mixed with the granules and powders of needle coke of various sizes, then graphite crushed and roasted crushed are added to form a mixed material after mixing; the mixed material and binder are stirred and mixed in a kneading pot Evenly, knead into a plastic paste;

(3) Pressing: the plastic paste is sent into the vertical tamping and horizontal press, and the plastic paste is charged and pre-pressed for 2-5min, and the paste is pressed at a speed of 25-26mm/second under a pressure of 32-35MN. Extrude from the extrusion nozzle, cut off the electrode when it reaches the required length, and obtain a green body with a preset size;

(4) Roasting: under the protection of fillers, the green body is roasted to obtain a roasted body;

(5) Impregnation and secondary roasting: After cleaning the surface of the roasted billet, preheat it to 260-380°C, put it into the impregnation device, vacuumize it to 8-9KPa, and then inject impregnated asphalt at a temperature of 180-200°C. Pressurize the system to 1.2-1.5MPa, return to the asphalt and cool the system; secondly roast the impregnated billet in the aforementioned (4) roasting furnace, so that the impregnated asphalt therein can remove volatile matter and coke;

(6) Graphitization: the calcined billet after the secondary roasting is placed in an internal heating series furnace, and in the presence of a protective medium, the impregnated roasted billet is heated to 2300-3000 ° C according to the preset power curve to obtain Graphitized blank;

(7) Mechanical processing: the graphitized blank is processed into the required electrode body and/or electrode joint through numerical control processing.

Preferably, the filler in step (4) is metallurgical coke, and the composition of the metallurgical coke is: ash ≤ 15%, fixed carbon ≥ 83%, moisture ≤ 0.5%.

Preferably, when processing the raw material needle coke, use the heat of combustion of the volatile matter in the raw material and add some fuel for calcination and natural temperature rise. The maximum temperature of calcination is controlled at 1250-1350°C, and the calcination time is 32-36h.

Preferably, after calcination, the coke is extracted by indirect cooling to below 100° C. through water jacket cooling circulating water.

Preferably, the density of the needle coke is controlled above 2.12g/cm ³ .

Preferably, the raw material needle coke is oil-based needle coke.

Preferably, the calcined needle coke is sieved into granular materials with a particle size of 0.5-22 mm, and powder materials with a particle size of 0.075-0.5 mm and smaller than 0.075 mm.

Preferably, in step (2), when the mixed material and the binder are kneaded, the kneading temperature in the kneading pot is controlled at 140-160° C., and the kneading time is 35-45 min.

Further, the particle size of graphene powder is less than 1mm. When it is mixed with needle coke, it is first mixed with needle coke powder with a particle size of 0.075-0.5mm, and then other particle sizes of needle coke particles and needle coke are added. Powder.

Preferably, in step (3), a green body of 625mm x 2550mm is obtained, and the bulk density of a qualified product is not lower than 1.70g/cm ³ .

The graphitized billet is machined into the required size, shape and precision by cutting to make the electrode body and joints that meet the requirements of use. Body processing includes boring and rough flat end face, outer circle turning and fine flat end face and thread milling. Conical joint machining includes: parting, facing, turning, threading, drilling, bolting and grooving.

The beneficial effects of the present invention are reflected in:

Graphene powder modification is added to the production of graphite electrodes, and the graphene powder is dispersed in the graphite electrode green body. When the graphitization process is performed, the graphene powder can be used as a crystal nucleus to allow the surrounding carbon atoms to continue on it. Crystal growth, the formation of larger graphite layered crystals, or the formation of polycrystalline, can induce the surrounding carbon atoms to transform from amorphous to crystalline, and generate new graphite layered crystals, thereby greatly improving the graphitization of the product Degree, reduce the resistivity of the product. The increase in the degree of graphitization can effectively reduce the value of the thermal expansion coefficient of its products, and at the same time improve the flexural strength. It can also significantly reduce the power consumption and electrode consumption in the process of electric furnace steelmaking, and effectively reduce the production cost of electric furnace steelmaking.

Detailed ways

Embodiments of the technical solution of the present invention will be described in detail below. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and therefore are only examples, rather than limiting the protection scope of the present invention.

It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application shall have the usual meanings understood by those skilled in the art to which the present invention belongs.

A preparation method for an ultra-high power graphite electrode, comprising the steps of:

Raw material treatment: The raw material needle coke is calcined at high temperature, using the combustion heat of the volatile matter in the raw material and adding part of the fuel for calcining and natural heating, the highest temperature is 1250-1350 °C, and the calcining time is 32-36h; after calcining The coke is discharged through indirect cooling to below 100°C by the water jacket cooling circulating water, and the contained moisture and volatile components are discharged to control the true density of the needle coke to not less than 2.12g/cm ³ . The calcined needle coke is crushed, pulverized, and sieved to obtain a material with a particle size of 0.5-22mm, and a powder material with a particle size of 0.5-0.075mm or less than 0.075mm.

Calculate and weigh granules, powders, and binders of various particle sizes, and the raw materials for preparation include the following components in weight percentages: graphene 0.3-0.7%, needle coke 65-73%, and binder 21-28% , 2-5% of roasted powder and 3-7.5% of graphite powder; wherein, the particle size composition of the needle coke is as follows: 16-22mm accounts for 12-18%, 6-16mm accounts for 10-15%, and 2-6mm accounts for 10% -14%, 0.075-0.5mm accounted for 22-33%, below 0.075mm accounted for 27-42%.

Kneading: Mix graphene with needle coke granules and powders of various sizes, then add graphite powder and roasted powder, and mix to form a mixture; stir the mixture and binder in a kneading pot, knead Synthetic plastic paste. When mixing, the graphene powder particle size is first mixed with needle coke with a particle size of 0.5-0.075mm, and then mixed with other particle sizes of needle coke particles and needle coke powder. When kneading, the temperature in the kneading pot is controlled to be 140-160°C, and the kneading time is 35-45min. The binder is medium-temperature pitch, the coking value of the medium-temperature pitch is ≮56%, the softening point is 94-99°C, the melting temperature is 108-114°C, the content of toluene insolubles is 28-32%, and the content of quinoline insolubles The content is 8-12%.

Pressing: the plastic paste is fed into the vertical tamping and horizontal press, and the plastic paste is charged, pre-pressed and extruded to obtain a green body of the required size.

Roasting: Roasting the green body under the protection of fillers to obtain a roasted body. The green body is roasted to carbonize the coal tar pitch in the green body. The specific temperature rise curve during roasting is shown in Table 1, and the temperature is naturally lowered at the highest temperature of 1100°C for 24-25 hours, and cooled for 70-78 hours to obtain the roasted body. The filling material is metallurgical coke, and its composition is: ash content ≤ 15%, fixed carbon ≥ 83%, moisture content ≤ 0.5%.

Table 1 Roasting heating curve

stage Temperature zone (℃) Heating rate (℃/h) Duration (h) 1 100-450 4-6 70 2 450-650 1-1.2 181 3 650-820 4-5 38 4 820-1100 10 28

Impregnation and secondary roasting: After cleaning the surface of the roasted billet, preheat it to 260-380°C, put it into the impregnation device, evacuate it to 8-9KPa, and then inject impregnated asphalt at a temperature of 180-200°C, pressurize the system To 1.2-1.5MPa, back to the asphalt and cool the system; the impregnated billet is roasted twice in the aforementioned roasting furnace, so that the impregnated asphalt therein can remove volatile matter and coke.

Graphitization: put the calcined billet after the second roasting in the internal heat series furnace, and under the condition of the presence of the protective medium, heat the impregnated roasted billet to 2300-3000°C according to the preset power curve to obtain the graphitized billet. The power transmission curves of the graphitization treatment are shown in Table 2.

Table 2 Power transmission curve

stage Power transmission time (h) Power(KW) Cumulative power transmission (KWH) 1 13 3250-6500 63375 2 17 6500-9400 198992 3 3 9400-11800 230792 4 32 11800-16000 675592

Machining: The graphitized billet is processed into the required electrode body and/or electrode joint by CNC machining.

According to the above preparation method, a qualified graphite electrode was prepared.

Example 1

Calculating and weighing the granules and powders and binders of various particle sizes, the preparation raw materials include the following components in weight percentages: 0.5% graphene, 66% needle coke, 25% binders, 4% roasted powder and Graphite crushed 4.5%; Among them, the particle size composition of needle coke is: 16-22mm accounted for 15%, 6-16mm accounted for 12%, 2-6mm accounted for 10%, 0.075-0.5mm accounted for 28%, 0.075mm accounted for 35% .

Kneading: Mix graphene with needle coke granules and powders of various sizes, then add graphite powder and roasted powder, and mix to form a mixture; stir the mixture and binder in a kneading pot, knead Synthetic plastic paste.

Pressing: Send the plastic paste into the vertical tamping and horizontal press, the plastic paste is charged and pre-pressed for 2 minutes, and the paste is extruded from the extrusion nozzle at a speed of 25.7mm/second under a pressure of 32MN to reach Cut the electrodes to the desired length to obtain a green body of 625mmx 2550mm, and the bulk density of qualified products is not less than 1.70g/cm ³ .

Roasting: Under the protection of filler metallurgical coke, the green body is roasted to obtain a roasted body.

Impregnation and secondary roasting: After cleaning the surface of the roasted billet, preheat it to 260°C, put it into the impregnation device, vacuumize it to 8-9KPa, and then inject impregnated asphalt at a temperature of 180°C, pressurize the system to 1.5MPa, Returning to asphalt and cooling the system; the impregnated body is secondarily roasted in the aforementioned (4) roasting furnace, so that the impregnated asphalt therein can remove volatile matter and coke.

Graphitization: Put the calcined billet after the second roasting in the internal heating series furnace, and in the presence of a protective medium, heat the impregnated roasted billet to 2300-3000°C according to the preset power curve to obtain a graphitized billet .

Machining: The graphitized billet is processed into the required electrode body and/or electrode joint by CNC machining.

Example 2

Calculating and weighing the granules and powders and binders of various particle sizes, the preparation raw materials include the following components in weight percentages: 0.3% graphene, 70% needle coke, 21% binders, 5% roasted powder and Graphite crushed 3.7%; Among them, the particle size composition of needle coke is: 16-22mm accounted for 12%, 6-16mm accounted for 10%, 2-6mm accounted for 12%, 0.075-0.5mm accounted for 22%, 0.075mm accounted for 42% .

Kneading: Mix graphene with needle coke granules and powders of various sizes, then add graphite powder and roasted powder, and mix to form a mixture; stir the mixture and binder in a kneading pot, knead Synthetic plastic paste.

Pressing: Send the plastic paste into the vertical tamping and horizontal press, the plastic paste is charged and pre-pressed for 5 minutes, and the paste is extruded from the extrusion nozzle at a speed of 25.7mm/s under a pressure of 35MN to reach Cut the electrodes to the desired length to obtain a green body of 625mmx 2550mm, and the bulk density of qualified products is not less than 1.70g/cm ³ .

Roasting: Under the protection of filler metallurgical coke, the green body is roasted to obtain a roasted body.

Impregnation and secondary roasting: After cleaning the surface of the roasted billet, preheat it to 380°C, put it into the impregnation device, vacuumize it to 8-9KPa, and then inject impregnated pitch at a temperature of 180-200°C, pressurize the system to 1.2 -1.5MPa, back to the bitumen and cool the system; the impregnated body is subjected to secondary roasting in the aforementioned (4) roasting furnace, so that the impregnated bitumen therein can remove volatile matter and coke.

Graphitization: Put the calcined billet after the second roasting in the internal heating series furnace, and in the presence of a protective medium, heat the impregnated roasted billet to 2300-3000°C according to the preset power curve to obtain a graphitized billet .

Machining: The graphitized billet is processed into the required electrode body and/or electrode joint by CNC machining.

Example 3

Calculating and weighing the granules and powders and binding agents of various particle sizes, the preparation raw materials include the following components in weight percentage: 0.7% graphene, 72% needle coke, 22% binding agent, 2% roasting powder and Graphite crushed 3.3%; Among them, the particle size composition of needle coke is: 16-22mm accounted for 18%, 6-16mm accounted for 12%, 2-6mm accounted for 10%, 0.075-0.5mm accounted for 33%, 0.075mm accounted for 27% .

Kneading: Mix graphene with needle coke granules and powders of various sizes, then add graphite powder and roasted powder, and mix to form a mixture; stir the mixture and binder in a kneading pot, knead Synthetic plastic paste.

Pressing: Send the plastic paste into the vertical tamping and horizontal press, the plastic paste is charged and pre-pressed for 4 minutes, and the paste is extruded from the extrusion nozzle at a speed of 25.7mm/second under a pressure of 34MN to reach Cut the electrodes to the desired length to obtain a green body of 625mmx 2550mm, and the bulk density of qualified products is not less than 1.70g/cm ³ .

Roasting: Under the protection of filler metallurgical coke, the green body is roasted to obtain a roasted body.

Impregnation and secondary roasting: After cleaning the surface of the roasted billet, preheat it to 300°C, put it into the impregnation device, vacuumize it to 8-9KPa, and then inject impregnated pitch at a temperature of 191°C, pressurize the system to 1.3MPa, Returning to asphalt and cooling the system; the impregnated body is secondarily roasted in the aforementioned (4) roasting furnace, so that the impregnated asphalt therein can remove volatile matter and coke.

Graphitization: Put the calcined billet after the second roasting in the internal heating series furnace, and in the presence of a protective medium, heat the impregnated roasted billet to 2300-3000°C according to the preset power curve to obtain a graphitized billet .

Machining: The graphitized billet is processed into the required electrode body and/or electrode joint by CNC machining.

Example 4

Calculation and weighing of granules and powders and binders of various particle sizes, the preparation raw materials include the following components in weight percentage: 0.5% graphene, 65% needle coke, 25% binder, 2% roasted powder and Graphite crushed 7.5%; Among them, the particle size composition of needle coke is: 16-22mm accounted for 16%, 6-16mm accounted for 15%, 2-6mm accounted for 14%, 0.075-0.5mm accounted for 25%, 0.075mm accounted for 30% .

Other processing steps are with embodiment 1.

Example 5

Calculating and weighing the granules and powders and binding agents of various particle sizes, the preparation raw materials include the following components in weight percentage: 0.4% graphene, 66% needle coke, 28% binding agent, 2% roasting powder and Graphite crushed 3.6%; Among them, the particle size composition of needle coke is: 16-22mm accounted for 15%, 6-16mm accounted for 12%, 2-6mm accounted for 10%, 0.075-0.5mm accounted for 28%, 0.075mm accounted for 35% .

Other processing steps are with embodiment 1.

The prepared graphite electrodes are tested for indicators, including resistivity, bulk density, flexural strength, elastic modulus and thermal expansion coefficient of graphitized products. According to YB/T 4090-2000, the indicators of graphitized products are as follows:

Table 3 Ultra-high power graphite electrode quality standard "YB/T4090-2000"

The quality index detection results of the ultra-high power graphite electrodes prepared according to Examples 1-5 are shown in the table below. The comparative example is the quality index of the ultra-high power graphite electrode obtained without adding graphene modification in the prior art.

Table 4 Index detection of ultra-high power graphite electrodes

It can be seen from the above table that the addition of graphene powder modification in the production of graphite electrodes can reduce the thermal expansion coefficient of the product, greatly reduce the resistivity of graphite electrodes and increase the flexural strength.

Carbon atoms in graphene form bonds with sp ² hybrid orbitals, and 3 of the 4 valence electrons of carbon atoms form sp ² bonds. π bonds are formed, and the newly formed π bonds are in a half-filled state. The pz orbital of each carbon atom perpendicular to the layer plane can form a large π bond of polyatoms throughout the entire layer, which makes graphene have excellent electrical and thermal conductivity. The present invention utilizes the excellent electrical conductivity and thermal conductivity of graphene, and adds graphene powder into the raw material of graphite electrode to achieve the purpose of reducing the resistivity of graphite electrode, reducing its thermal expansion coefficient CTE value and improving its strength.

By adding graphene powder to the raw material of graphite electrode and dispersing it in the graphite electrode green body, these fine graphene powder will play a huge role in the graphitization process, which can be used as a crystal nucleus to make the surrounding The carbon atoms continue to grow on it to form larger graphite layered crystals, or generate polycrystals, and induce the transformation of surrounding carbon atoms from amorphous to crystalline to form new graphite layered crystals. Thereby greatly improving the degree of graphitization of the product and reducing the resistivity of the product. The increase in the degree of graphitization will reduce the thermal expansion coefficient of the product, and at the same time, the flexural strength of the product will also be greatly improved.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. All of them should be covered by the scope of the claims and description of the present invention.

Claims (10)

1. An ultra-high power graphite electrode is characterized in that the preparation raw materials include the following components in weight percent: graphene 0.3-0.7%, needle coke 65-73%, binding agent 21-28%, roasted powder 2 -5% and crushed graphite 3-7.5%. 2. The ultra-high power graphite electrode according to claim 1, wherein the particle size of the needle coke is composed of: 16-22mm accounts for 12-18%, 6-16mm accounts for 10-15%, and 2-6mm It accounts for 10-14%, 0.075-0.5mm accounts for 22-33%, and below 0.075mm accounts for 27-42%. 3. The ultra-high power graphite electrode according to claim 1, characterized in that, the particle size of the roasted crushed particles is 1-2 mm; the particle size of the graphite crushed particles is 1-2 mm; the particle size of the graphene is less than 1 mm. 4. The ultra-high power graphite electrode according to claim 1, wherein the binder is a medium-temperature pitch, the coking value of the medium-temperature pitch is ≥56%, the softening point is 94-99° C., and the melting temperature is 108-114°C, the toluene insoluble content is 28-32%, and the quinoline insoluble content is 8-12%. 5. a method for manufacturing the ultra-high power graphite electrode described in any one of claims 1-4, is characterized in that, comprises the steps: (1) Raw material processing: The raw material needle coke is processed into granules and powders of needle coke of various sizes through calcination, secondary crushing, grinding and screening; weigh graphene, graphite crushed, roasted crushed, binder And granular materials and powder materials of needle coke of various sizes; (2) Kneading: Graphene is mixed with the granules and powders of needle coke of various sizes, then graphite crushed and roasted crushed are added to form a mixed material after mixing; the mixed material and binder are stirred and mixed in a kneading pot Evenly, knead into a plastic paste; (3) Pressing: the plastic paste is sent into the vertical tamping and horizontal press, and the plastic paste is charged and pre-pressed for 2-5min, and the paste is pressed at a speed of 25-26mm/second under a pressure of 32-35MN. Extrude from the extrusion nozzle, cut off the electrode when it reaches the required length, and obtain a green body with a preset size; (4) Roasting: under the protection of fillers, the green body is roasted to obtain a roasted body; (5) Impregnation and secondary roasting: After cleaning the surface of the roasted billet, preheat it to 260-380°C, put it into the impregnation device, vacuumize it to 8-9KPa, and then inject impregnated asphalt at a temperature of 180-200°C. Pressurize the system to 1.2-1.5MPa, return to the asphalt and cool the system; secondly roast the impregnated billet in the aforementioned (4) roasting furnace, so that the impregnated asphalt therein can remove volatile matter and coke; (6) Graphitization: the calcined billet after the secondary roasting is placed in an internal heating series furnace, and in the presence of a protective medium, the impregnated roasted billet is heated to 2300-3000 ° C according to the preset power curve to obtain Graphitized blank; (7) Mechanical processing: the graphitized blank is processed into the required electrode body and/or electrode joint through numerical control processing. 6. The manufacturing method as claimed in claim 5, characterized in that, when the raw material is processed, it uses the combustion heat of the volatile matter in the raw material and adds part of the fuel to carry out calcination and natural heating, and the maximum temperature of calcination is controlled at 1250-1350°C , The calcination time is 32-36h; after calcination, the coke is discharged by indirect cooling to below 100°C through the water jacket cooling circulating water; the density of the needle coke is controlled above 2.12g/cm ³ . 7. The manufacturing method according to claim 5, characterized in that the calcined needle coke is sieved into granular materials with a particle size of 0.5-22 mm, and powder materials with a particle size of 0.075-0.5 mm and smaller than 0.075 mm. 8. The manufacturing method according to claim 5, characterized in that, in step (2), when the mixed material and the binder are kneaded, the temperature in the kneading pot is controlled to be 140-160°C, and the kneading time is 35- 45min. 9. The manufacturing method according to claim 5, characterized in that, in step (3), a green body of 625mm x 2550mm is obtained, and the bulk density of the qualified product is not less than 1.70g/cm ³ . 10. The manufacturing method according to claim 5, characterized in that, in step (4), the filler is metallurgical coke with the following components: ash ≤ 15%, fixed carbon ≥ 83%, moisture ≤ 0.5%.