High-end isostatic pressing graphite raw material and preparation method thereof

Abstract

The application discloses a kind of high-end isostatic pressing graphite raw material and preparation method thereof, comprising the following steps: S1, high-quality acicular coke is selected as main material, the main material is crushed and shaped, then add pitch to obtain burr main material after burr treatment;S2, the burr main material is used as forming raw material, the forming raw material is obtained by extrusion molding and secondary granulation Forming particles;S3, add coating pitch to forming particles, carry out surface modification treatment and carbonization treatment in anaerobic environment to obtain high-end isostatic pressing graphite raw material.The application can develop high-end isostatic pressing graphite raw material with excellent comprehensive performance, homogeneity and stability, to meet the production needs of high-end isostatic pressing graphite in different industrial processing chains.

Description

Technical Field

[0001] This invention relates to the field of isostatic graphite technology, and more specifically, to a raw material for high-end isostatic graphite and its preparation method. Background Technology

[0002] Isostatic graphite is produced by pressing high-purity graphite using an isostatic pressing process. In addition to the excellent properties of general graphite, it also possesses characteristics such as isotropy, corrosion resistance, superior mechanical properties, good heat resistance, low coefficient of thermal expansion, and fine structure. It is widely used in solar energy, nuclear energy, metallurgy, chemical industry, machinery, electrical engineering, semiconductors, aerospace, photovoltaics, new energy batteries, nuclear power, electrical discharge machining (EDM), smelting, and rare earth industries.

[0003] Currently, China's production technology foundation for isostatic graphite is relatively weak. Foreign companies maintain technological barriers, particularly regarding core technologies for producing large-size, high-purity, and fine-structure high-end isostatic graphite products. This has resulted in a failure to effectively improve the quantity and quality of isostatic graphite in China, with high-end products still reliant on imports. Furthermore, foreign companies offer customized solutions for various downstream sub-sectors, while domestic products are generally differentiated by size and volumetric density, lacking targeted customization services.

[0004] With the rapid development of my country's semiconductor, lithium battery, photovoltaic solar energy, EDM and mold processing, nuclear power and other industries, the market demand for customized high-end isostatic graphite is also increasing. Therefore, it is urgent to independently develop customized high-end graphite products that match the above industries.

[0005] Based on the current domestic production situation and starting from the final product, this invention comprehensively characterizes the quality of high-end isostatic graphite products from abroad. Starting from the raw materials for producing high-end isostatic graphite, this invention develops high-end isostatic graphite raw materials with excellent comprehensive performance, homogeneity, stability, and meeting the requirements of use and different industrial processing chains, thus filling the gap of zero technology for high-end graphite products in China. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a high-end isostatic graphite raw material and its preparation method, which can develop a high-end isostatic graphite raw material with excellent comprehensive performance, homogeneity, and stability, meeting the production needs of high-end isostatic graphite in different industrial processing chains.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect of this invention provides a method for preparing raw materials for high-end isostatic graphite, comprising the following steps:

[0009] S1 uses high-quality needle coke as the main material. The main material is crushed and shaped, and then asphalt is added for deburring treatment to obtain deburred main material.

[0010] S2, the deburred main material is used as the molding raw material, and the molding raw material is obtained into molding particles through extrusion molding and secondary granulation;

[0011] S3 involves adding coated asphalt to the molded particles and then performing surface modification and carbonization treatments in an oxygen-free environment to obtain high-end isostatic graphite raw materials.

[0012] Preferably, in step S1, the high-quality needle coke is selected from coal-based needle coke or oil-based needle coke; the CTE of the high-quality needle coke is ≤0.9×10⁻⁶. -6 / ℃; True specific gravity ≥2.14g / cm³ 3 The particle length-to-width ratio is ≥1.75, and the powder resistivity is 500~600μΩm.

[0013] Preferably, in step S1, the crushing process uses an ultrafine mill to grind the main material to a D50 of 1-3 μm;

[0014] The tapped density of the main material after the shaping process is ≥1.0 g / cm³. 3 ;

[0015] During the deburring treatment, the amount of asphalt added is 2-5 wt% of the main material, the deburring treatment temperature is 60-85°C higher than the softening point of the asphalt, and the deburring treatment time is 30-90 min.

[0016] Preferably, the molding raw material further includes deburring auxiliary materials;

[0017] The amount of the deburring auxiliary material added shall not exceed 35 wt% of the total amount of the molding raw material;

[0018] The preparation process of the deburring auxiliary material is as follows: petroleum coke, pitch coke or equal-sized coke is selected as auxiliary material, the auxiliary material is crushed and shaped, and then pitch is added for deburring treatment to obtain the deburring auxiliary material.

[0019] Preferably, the excipients are crushed using an ultrafine mill to grind them to a D50 of 1–3 μm;

[0020] The tapped density of the shaped auxiliary material is ≥1.0 g / cm³. 3 ;

[0021] During the deburring treatment of the auxiliary material, the amount of asphalt added is 2-5 wt% of the auxiliary material, the deburring treatment temperature is 60-85°C higher than the softening point of the asphalt, and the deburring treatment time is 30-90 min.

[0022] Preferably, in step S2:

[0023] The extrusion molding and secondary granulation time is 60-120 min;

[0024] The shaped particles have a D50 of 3–5 μm.

[0025] Preferably, in step S3:

[0026] The coating asphalt is selected from oil-based coating asphalt with a softening point ≥200℃ or oil-based coating asphalt, and the D50 of the coating asphalt is 1~3μm;

[0027] The amount of coated asphalt added is 8-15 wt% of the shaped particles.

[0028] Preferably, in step S3:

[0029] During the surface modification process, the treatment temperature is 30-60°C higher than the softening point of the coated asphalt, and the treatment time is 2-5 hours.

[0030] During the carbonization process, the carbonization heating rate is ≥5℃ / min, the carbonization temperature is 450~550℃, and the carbonization time is 1~3h.

[0031] The second aspect of this invention provides a high-end isostatic graphite raw material prepared by the method for preparing high-end isostatic graphite raw materials as described in the first aspect of this invention. The high-end isostatic graphite raw material has a D50 of 3–5 μm, a powder resistivity ≤600 μΩm, and a tap density ≥1.1 g / cm³. 3 Isotropy ≤ 1.15, thermal conductivity ≥ 50 W / m, porosity ≤ 20%.

[0032] To address the issues of fine cracks and spalling that occur in large-format graphite products prepared using ultrafine aggregates (D50≯5μm) in China, and the fact that the poor stability and homogenization of the aggregates limit their application to low-end graphite products, this invention reshapes the aggregates (e.g., surface modification, alteration, and secondary granulation). The treated aggregates can be customized according to customer needs to produce ultra-large (φ≮1500) ultrafine isostatic graphite with excellent overall performance, homogeneity, and stability, meeting the requirements of high-end carbonaceous material applications. Attached Figure Description

[0033] Figure 1 This is a schematic flowchart of a method for preparing raw materials for high-end isostatic graphite according to an embodiment of the present invention.

[0034] Figure 2 This is a schematic flowchart illustrating a method for preparing raw materials for high-end isostatic graphite according to another embodiment of the present invention.

[0035] Figure 3 This is a diagram showing the shape changes of the raw material in the preparation method of the high-end isostatic graphite raw material of the present invention. Detailed Implementation

[0036] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with embodiments.

[0037] Combination Figures 1-3 As shown, the present invention discloses a method for preparing raw materials for high-end isostatic graphite, comprising the following steps:

[0038] S1 uses high-quality needle coke as the main material. The main material is crushed and shaped, and then asphalt is added for deburring treatment to obtain deburred main material.

[0039] This step mainly involves macroscopic anisotropic processing of the main material, selecting high-quality needle coke as the main material, such as high-quality needle coke from coal-based or oil-based sources. The performance of these high-quality needle cokes must meet the following requirement: CTE ≤ 0.9 × 10⁻⁶. -6 / ℃; True specific gravity ≥2.14g / cm³ 3 The particle length-to-width ratio is ≥1.75, and the powder resistivity is 500–600 μΩm. The main material is crushed and shaped. The crushing process uses an ultrafine mill to grind the main material to a D50 (median diameter) of 1–3 μm. After shaping, the tap density of the main material is ≥1.0 g / cm³. 3 .

[0040] Add 2-5 wt% asphalt (such as ordinary modified asphalt SP110℃ or low QI modified impregnated asphalt SP110℃ or ultra-high temperature asphalt for negative electrode SP200℃) to the main material after shaping for deburring treatment. The deburring treatment temperature is 60-85℃ higher than the softening point of the asphalt, and the deburring treatment time is 30-90 min.

[0041] S2, the deburred main material is used as the molding raw material, and the molding raw material is obtained into molding particles through extrusion molding and secondary granulation.

[0042] This step is an extrusion molding and secondary granulation process. The deburred main material is used as the molding raw material. Through extrusion molding and secondary granulation for 60 to 120 minutes, molded particles with a D50 of 3 to 5 μm are obtained.

[0043] The molding raw materials in this step also include deburring auxiliary materials, that is, the main deburring material and the deburring auxiliary materials are used together as molding raw materials. The amount of deburring auxiliary materials added does not exceed 35 wt% of the total molding raw materials; the preparation process of the deburring auxiliary materials is as follows: petroleum coke, pitch coke or equal-dimensional coke is selected as auxiliary materials, and the auxiliary materials are crushed and shaped. The crushing treatment of the auxiliary materials is carried out by grinding the auxiliary materials to a D50 of 1-3 μm using an ultrafine mill; the tap density of the auxiliary materials after shaping treatment is ≥1.0 g / cm³. 3 Then, asphalt (such as ordinary modified asphalt SP110℃ or low QI modified impregnated asphalt SP110℃ or ultra-high temperature asphalt for negative electrode SP200℃) is added for deburring treatment to obtain deburred auxiliary material. During the deburring treatment of the auxiliary material, the amount of asphalt added is 2-5 wt% of the auxiliary material, the deburring treatment temperature is 60-85℃ higher than the softening point of the asphalt, and the deburring treatment time is 30-90 min.

[0044] S3 involves adding coated asphalt to the molded particles and then performing surface modification and carbonization treatments in an oxygen-free environment to obtain high-end isostatic graphite raw materials.

[0045] In this step, coated asphalt is added to the molded particles. The coated asphalt used is oil-based coated asphalt with a softening point ≥200℃, and the D50 of the coated asphalt is 1-3μm. The amount of coated asphalt added is 8-15wt% of the molded particles. Under an oxygen-free environment, the material surface is modified for 2-5 hours. During the surface modification process, the treatment temperature is 30-60℃ higher than the softening point of the coated asphalt. Then, carbonization is carried out at 450-550℃ under an oxygen-free environment for 1-3 hours, with a carbonization heating rate ≥5℃ / min, finally obtaining the raw material for isostatic graphite.

[0046] The properties of the high-end isostatic graphite raw material prepared above are as follows: D50 is 3-5 μm, powder resistivity is ≤600 μΩm, and tap density is ≥1.1 g / cm³. 3 Isotropy ≤ 1.15, thermal conductivity ≥ 50 W / m, porosity ≤ 20%.

[0047] The high-end isostatic graphite raw material prepared above can be processed into high-end isostatic graphite through mixing and molding processes. The specific process can be referred to as follows: (1) Put the high-end isostatic graphite raw material into a mixing pot and dehydrate it at 140-160℃ for 30-50 minutes; (2) Vacuum the material and let it cool naturally to room temperature; (3) Slowly depressurize it to normal pressure, open the lid and add the binder asphalt SP. 200~250℃ (Raw material for high-end isostatic graphite: asphalt = 1:0.3~1wt%, that is, asphalt accounts for 0.3~1wt% of the mass of raw material for high-end isostatic graphite), vacuum, and knead for 60~90min at SP+85~95℃; (4) After cooling to room temperature, take out the sample, perform secondary grinding, and control the particle D50 to be 2.1~2.3 times the primary particle D50; (5) Quickly pre-molde and then isostatically press to obtain high-end isostatic graphite with a bulk density of 1.8~2.0g / cm³. 3 It has a compressive strength of 125–150 MPa, a flexural strength of 85–90 MPa, and a resistivity of ≤21.5 Ω·m.

[0048] The following specific embodiments further illustrate this point, wherein the high-quality needle coke used in the following embodiments meets the following performance requirement: CTE ≤ 0.9 × 10⁻⁶. -6 / ℃; True specific gravity ≥2.14g / cm³ 3 The particle length-to-width ratio is ≥1.75, and the powder resistivity is 500~600μΩm.

[0049] Example 1

[0050] Combination Figure 1 As shown, this embodiment provides a method for preparing raw materials for high-end isostatic graphite, as detailed below:

[0051] (1) Mitsubishi needle coke from Japan with a particle size of ≤1mm was selected as the main material. The coke was ground to a median diameter of 2.251μm using an ultrafine mill, and then shaped until the tap density was ≥1.000g / cm³. 3 Alternatively, a median diameter of 2.251 μm and a tap density of ≥1.000 g / cm³ can be directly selected. 3 The main ingredient is Mitsubishi needle coke from Japan;

[0052] (2) 7 kg of Mitsubishi needle coke with a median diameter of 2.251 μm and 0.14 kg of ordinary modified asphalt with a softening point of 110℃ were put into a kneading pot and deburred at 170℃ for 30 min. After the deburring treatment, the temperature of the material dropped to below 100℃ and was transferred to a granulation kettle for extrusion molding and secondary granulation. After 70 min, the shaped granules were obtained.

[0053] (3) Transfer the shaped particles to the coating kettle, add 0.5712 kg of oil-based coating asphalt at SP205℃, and treat the surface of the shaped particles for 2 hours at 235℃ under oxygen-free conditions. Then, raise the temperature to 450℃ at a heating rate of 3℃ / min and carbonize it for 1 hour under oxygen-free conditions. Then, cool it down naturally to below 100℃ to obtain raw materials for high-end isostatic graphite.

[0054] The properties of the high-end isostatic graphite raw material prepared in this embodiment are as follows: D50 is 3.15 μm, powder resistivity is 300 μΩm, and tap density is 1.12 g / cm³. 3 It has an isotropy of 1.12, a thermal conductivity of 52 W / m, and a porosity of 19%.

[0055] The above-mentioned high-end isostatic graphite raw materials were used to prepare high-end isostatic graphite: the high-end isostatic graphite raw materials were transferred to a kneading pot; after dehydration and degassing at 140℃ for 35 min, vacuum was applied and the material was allowed to cool naturally to room temperature. The pressure was then slowly released to atmospheric pressure, and 2.3134 kg of SP210℃ coal-based binder pitch (the coal-based binder pitch was 2-5 wt% of the mass of the high-end isostatic graphite raw materials) was added to the kneading pot. Vacuum was applied, and the material was kneaded at 295℃ under oxygen-free conditions for 60 min. The material was then allowed to cool naturally to below 100℃, and the paste was subjected to secondary grinding and crushed to about 10 μm. The material was then discharged and shaped. High-end isostatic graphite was obtained through rapid pre-molding and isostatic pressing. Its properties are shown in Table 1.

[0056] Table 1

[0057]

[0058] Example 2

[0059] Combination Figure 2 As shown, this embodiment provides a method for preparing raw materials for high-end isostatic graphite, as detailed below:

[0060] (1) Korean Pohang needle coke with a particle size of ≤1mm was selected as the main material. The coke was ground to a median diameter of 1.452μm using an ultrafine mill, and then shaped until the tap density was ≥1.000g / cm³. 3 Alternatively, a median diameter of 1.452 μm and a tap density of ≥1.000 g / cm³ can be directly selected. 3 South Korean POSCO needle coke is used as the main ingredient;

[0061] (2) Petroleum coke with particles ≤1mm was selected as an auxiliary material. The coke was ground to a median diameter of 2.152μm using an ultrafine mill, and then shaped until the tapped density was ≥1.000g / cm³. 3 Alternatively, a median diameter of 2.152 μm and a tap density of ≥1.000 g / cm³ can be directly selected.3 Petroleum coke is used as an auxiliary material;

[0062] (3) 6.16 kg of needle coke from Pohang, South Korea with a median diameter of 1.452 μm and 0.84 kg of petroleum coke with a median diameter of 2.152 μm were thoroughly mixed in a mixer and then transferred to a kneading pot. 0.175 kg of low QI modified impregnated asphalt with a softening point of 110℃ was added to the kneading pot and deburred at 180℃ for 45 min. After the temperature of the material after deburring was reduced to below 100℃, it was transferred to a granulation kettle for extrusion molding and secondary granulation. After 80 min, shaped granules were obtained.

[0063] (4) Transfer the shaped particles to the coating kettle, add 0.7 kg of coal-based coating pitch at SP210℃, and modify the surface of the shaped particles for 3 hours at 245℃ under oxygen-free conditions. Then, raise the temperature to 480℃ at a heating rate of 2.5℃ / min and carbonize it for 1.5 hours under oxygen-free conditions. Finally, allow it to cool naturally to below 100℃ to obtain raw materials for high-end isostatic graphite.

[0064] The properties of the high-end isostatic graphite raw material prepared in this embodiment are as follows: D50 is 2.93 μm, powder resistivity is 235 μΩm, and tap density is 1.15 g / cm³. 3 The isotropy is 1.05, the thermal conductivity is 53 W / m, and the porosity is 17%. High-end isostatic graphite was prepared from the above-mentioned raw materials: the raw materials were transferred to a kneading pot; after dehydration and degassing at 150℃ for 38 min, a vacuum was applied, and the mixture was allowed to cool naturally to room temperature. The pressure was then slowly released to atmospheric pressure, and 3.85 kg of SP215℃ coal-based binder pitch (the coal-based binder pitch being 2-5 wt% of the raw materials) was added to the kneading pot. A vacuum was applied, and the mixture was kneaded at 305℃ under oxygen-free conditions for 90 min. The mixture was then allowed to cool naturally to below 100℃, and the paste was subjected to secondary grinding to break it to approximately 8.4 μm. The material was then discharged and shaped. High-end isostatic graphite was obtained through rapid pre-molding and isostatic pressing. Its properties are shown in Table 2.

[0065] Table 2

[0066]

[0067] Example 3

[0068] Combination Figure 2 As shown, this embodiment provides a method for preparing raw materials for high-end isostatic graphite, as detailed below:

[0069] (1) Shandong Yida coal-series needle coke with a particle size of ≤1mm was selected as the main material. The coke was ground to a median diameter of 3.000μm using an ultra-micro mill, and then shaped until the tapped density was ≥1.000g / cm³.3 Alternatively, a median diameter of 3.000 μm and a tap density of ≥1.000 g / cm³ can be directly selected. 3 Shandong Yida coal-series needle coke is used as the main raw material;

[0070] (2) Petroleum coke with particles ≤1mm was selected as an auxiliary material. The coke was ground to a median diameter of 2.152μm using an ultrafine mill, and then shaped until the tapped density was ≥1.000g / cm³. 3 Alternatively, a median diameter of 2.152 μm and a tap density of ≥1.000 g / cm³ can be directly selected. 3 Petroleum coke is used as an auxiliary material;

[0071] (3) 5.88 kg of Shandong Yida coal-series needle coke with a median diameter of 3.000 μm and 1.12 kg of pitch coke with a median diameter of 2.952 μm were thoroughly mixed in a mixer and then transferred to a kneading pot. 0.21 kg of negative electrode was added to the kneading pot with ultra-high temperature pitch SP200℃ and deburred at 270℃ for 50 min. After the temperature of the material after deburring treatment dropped to below 100℃, it was transferred to a granulation kettle for extrusion molding and secondary granulation. After 90 min, the shaped granules were obtained.

[0072] (4) Transfer the shaped particles to the coating kettle, add 0.8652 kg of coal-based coating pitch at SP200℃, and modify the surface of the shaped particles for 4 hours at 245℃ under oxygen-free conditions. Then, raise the temperature to 500℃ at a heating rate of 2℃ / min and carbonize it for 2 hours under oxygen-free conditions. Finally, let it cool down naturally to below 100℃ to obtain raw materials for high-end isostatic graphite.

[0073] The properties of the high-end isostatic graphite raw material prepared in this embodiment are as follows: D50 is 5 μm, powder resistivity is 425 μΩm, and tap density is 1.2 g / cm³. 3 It has an isotropy of 1.01, a thermal conductivity of 59 W / m, and a porosity of 15%.

[0074] The above-mentioned high-end isostatic graphite raw materials were used to prepare high-end isostatic graphite: the high-end isostatic graphite raw materials were transferred to a kneading pot; after dehydration and degassing at 145℃ for 40 min, vacuum was applied and the mixture was allowed to cool naturally to room temperature, and the pressure was slowly released to atmospheric pressure. 3.23 kg of SP220℃ coal-based binder pitch (the coal-based binder pitch was 2-5 wt% of the mass of the high-end isostatic graphite raw materials) was added to the kneading pot, vacuum was applied, and the mixture was kneaded at 315℃ under oxygen-free conditions for 70 min. After cooling naturally to below 100℃, the paste was subjected to secondary grinding and crushed to about 9.9 μm. The material was then discharged and shaped. High-end isostatic graphite was obtained through rapid pre-molding and isostatic pressing. Its properties are shown in Table 3.

[0075] Table 3

[0076]

[0077] Example 4

[0078] Combination Figure 2 As shown, this embodiment provides a method for preparing raw materials for high-end isostatic graphite, as detailed below:

[0079] (1) Jingyang oil-based needle coke with a particle size of ≤1mm was selected as the main material. The coke was ground to a median diameter of 2.801μm using an ultrafine mill, and then shaped until the tap density was ≥1.000g / cm³. 3 Alternatively, a median diameter of 2.801 μm and a tap density of ≥1.000 g / cm³ can be directly selected. 3 Jingyang oil-based needle coke was used as the main raw material;

[0080] (2) Isogonal coke with particles ≤1mm was selected as the auxiliary material. The coke was ground to a median diameter of 2.012μm using an ultrafine mill, and then shaped until the tap density was ≥1.000g / cm³. 3 Alternatively, a median diameter of 2.012 μm and a tap density of ≥1.000 g / cm³ can be directly selected. 3 The isocyanate coke was used as an auxiliary material;

[0081] (3) 5.39 kg of Jingyang oil-based needle coke with a median diameter of 2.801 μm and 1.61 kg of square coke with a median diameter of 2.012 μm were thoroughly mixed in a mixer and then transferred to a kneading pot. 0.245 kg of ordinary modified asphalt with a softening point of 110℃ was added to the kneading pot and deburred at 285℃ for 60 min. After the temperature of the material after deburring was reduced to below 100℃, it was transferred to a granulation kettle for extrusion molding and secondary granulation. After 100 min, shaped granules were obtained.

[0082] (4) Transfer the shaped particles to the coating kettle, add 0.9415 kg of coal-based coating pitch at SP235℃, and modify the surface of the shaped particles for 4.5 h at 285℃ under oxygen-free conditions. Then, raise the temperature to 520℃ at a heating rate of 3.5℃ / min and carbonize it for 1.5 h under oxygen-free conditions. Finally, let it cool down naturally to below 100℃ to obtain raw materials for high-end isostatic graphite.

[0083] The properties of the high-end isostatic graphite raw material prepared in this embodiment are as follows: D50 is 4.21 μm, powder resistivity is 387 μΩm, and tap density is 1.3 g / cm³. 3The isotropy is 1.15, the thermal conductivity is 61 W / m, and the porosity is 13%. High-end isostatic graphite was prepared from the above-mentioned raw materials: the raw materials were transferred to a kneading pot; after dehydration and degassing at 155℃ for 45 min, a vacuum was applied, and the mixture was allowed to cool naturally to room temperature. The pressure was then slowly released to atmospheric pressure, and 6.5492 kg of SP235℃ oil-based binder pitch (the oil-based binder pitch being 2-5 wt% of the raw materials) was added to the kneading pot. A vacuum was applied, and the mixture was kneaded at 320℃ under oxygen-free conditions for 80 min. The mixture was then allowed to cool naturally to below 100℃, and the paste was subjected to secondary grinding to a particle size of approximately 10.13 μm. The material was then discharged and shaped. High-end isostatic graphite was obtained through rapid pre-molding and isostatic pressing. Its properties are shown in Table 4.

[0084] Table 4

[0085]

[0086] Example 5

[0087] Combination Figure 2 As shown, this embodiment provides a method for preparing raw materials for high-end isostatic graphite, as detailed below:

[0088] (1) Baohua needle coke with a particle size of ≤1mm was selected as the main material. The coke was ground to a median diameter of 1.756μm using an ultra-micro mill, and then shaped until the tap density was ≥1.000g / cm³. 3 Alternatively, a median diameter of 1.756 μm and a tap density of ≥1.000 g / cm³ can be directly selected. 3 Baohua needle coke is used as the main ingredient;

[0089] (2) Pitch coke with a particle size of ≤1mm was selected as an auxiliary material. The coke was ground to a median diameter of 1.812μm using an ultrafine mill, and then shaped until the tapped density was ≥1.000g / cm³. 3 Alternatively, a median diameter of 1.812 μm and a tap density of ≥1.000 g / cm³ can be directly selected. 3 Pitch coke is used as an auxiliary material;

[0090] (3) 4.76 kg of Baohua needle coke with a median diameter of 1.756 μm and 2.24 kg of asphalt coke with a median diameter of 1.812 μm were thoroughly mixed in a mixer and then transferred to a kneading pot. 0.35 kg of low QI modified impregnated asphalt with a softening point of 110℃ was added to the kneading pot and deburred at 195℃ for 75 min. After the temperature of the material after deburring was reduced to below 100℃, it was transferred to a granulation kettle for extrusion molding and secondary granulation. After 120 min, shaped granules were obtained.

[0091] (4) Transfer the shaped particles to the coating kettle, add 1.1025 kg of coal-based coating pitch at SP250℃, and after surface modification treatment of the shaped particles for 5 h at 310℃ and under oxygen-free conditions, raise the temperature to 550℃ at a heating rate of 1℃ / min, carbonize under oxygen-free conditions for 2.5 h, and then cool naturally to below 100℃ to obtain raw materials for high-end isostatic graphite.

[0092] The properties of the high-end isostatic graphite raw material prepared in this embodiment are as follows: D50 is 3.67 μm, powder resistivity is 405 μΩm, and tap density is 1.1 g / cm³. 3 It has an isotropy of 1.1, a thermal conductivity of 73 W / m, and a porosity of 16%.

[0093] The above-mentioned high-end isostatic graphite raw materials were used to prepare high-end isostatic graphite: the high-end isostatic graphite raw materials were transferred to a kneading pot; after dehydration and degassing at 160℃ for 50 min, vacuum was applied and the mixture was allowed to cool naturally to room temperature, and the pressure was slowly released to atmospheric pressure. 6.3394 kg of SP250℃ coal-based binder pitch (the coal-based binder pitch was 2-5 wt% of the mass of the high-end isostatic graphite raw materials) was added to the kneading pot, vacuum was applied, and the mixture was kneaded at 338℃ under oxygen-free conditions for 90 min. After cooling naturally to below 100℃, the paste was subjected to secondary grinding and crushed to about 9.2 μm. The material was then discharged and shaped. High-end isostatic graphite was obtained through rapid pre-molding and isostatic pressing. Its properties are shown in Table 5.

[0094] Table 5

[0095]

[0096] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for preparing raw materials for high-end isostatic graphite, characterized in that, Includes the following steps: S1 uses high-quality needle coke as the main material. The main material is crushed and shaped, and then asphalt is added for deburring treatment to obtain deburred main material. S2, the deburred main material is used as the molding raw material, and the molding raw material is obtained into molding particles through extrusion molding and secondary granulation. S3 involves adding coated asphalt to the molded particles and then performing surface modification and carbonization treatments in an oxygen-free environment to obtain high-end isostatic graphite raw materials.

2. The method for preparing raw materials for high-end isostatic graphite according to claim 1, characterized in that: In step S1, the high-quality needle coke is selected from coal-based needle coke or oil-based needle coke; the CTE of the high-quality needle coke is ≤0.9×10⁻⁶. -6 / ℃; True specific gravity ≥2.14g / cm³ 3 The particle length-to-width ratio is ≥1.75, and the powder resistivity is 500~600μΩm.

3. The method for preparing raw materials for high-end isostatic graphite according to claim 1, characterized in that: In step S1, the crushing process uses an ultra-fine mill to grind the main material to a D50 of 1-3 μm; The tapped density of the main material after the shaping process is ≥1.0 g / cm³. 3 ; During the deburring treatment, the amount of asphalt added is 2-5 wt% of the main material, the deburring treatment temperature is 60-85°C higher than the softening point of the asphalt, and the deburring treatment time is 30-90 min.

4. The method for preparing raw materials for high-end isostatic graphite according to claim 1, characterized in that: The molding raw materials also include deburring auxiliary materials; The amount of the deburring auxiliary material added shall not exceed 35 wt% of the total amount of the molding raw material; The preparation process of the deburring auxiliary material is as follows: petroleum coke, pitch coke or equal-sized coke is selected as auxiliary material, the auxiliary material is crushed and shaped, and then pitch is added for deburring treatment to obtain the deburring auxiliary material.

5. The method for preparing raw materials for high-end isostatic graphite according to claim 4, characterized in that: The excipients are crushed using an ultra-fine mill to grind them to a D50 of 1-3 μm. The tapped density of the shaped auxiliary material is ≥1.0 g / cm³. 3 ; During the deburring treatment of the auxiliary material, the amount of asphalt added is 2-5 wt% of the auxiliary material, the deburring treatment temperature is 60-85°C higher than the softening point of the asphalt, and the deburring treatment time is 30-90 min.

6. The method for preparing raw materials for high-end isostatic graphite according to claim 1, characterized in that: In step S2: The extrusion molding and secondary granulation time is 60-120 min; The shaped particles have a D50 of 3–5 μm.

7. The method for preparing raw materials for high-end isostatic graphite according to claim 1, characterized in that: In step S3: The coating asphalt is selected from oil-based coating asphalt with a softening point ≥200℃ or oil-based coating asphalt, and the D50 of the coating asphalt is 1~3μm. The amount of coated asphalt added is 8-15 wt% of the shaped particles.

8. The method for preparing raw materials for high-end isostatic graphite according to claim 1, characterized in that: In step S3: During the surface modification process, the treatment temperature is 30-60°C higher than the softening point of the coated asphalt, and the treatment time is 2-5 hours. During the carbonization process, the carbonization heating rate is ≥5℃ / min, the carbonization temperature is 450~550℃, and the carbonization time is 1~3h.

9. A high-end isostatic graphite raw material prepared by the method for preparing high-end isostatic graphite as described in any one of claims 1 to 8, characterized in that, The raw material for the high-end isostatic graphite has a D50 of 3–5 μm, a powder resistivity of ≤600 μΩm, and a tap density of ≥1.1 g / cm³. 3 Isotropy ≤ 1.15, thermal conductivity ≥ 50 W / m, porosity ≤ 20%.

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