A method for preparing high-density graphite material using coal-tar pitch macromolecular components as raw materials

Abstract

This invention relates to a method for preparing high-density graphite materials using coal tar pitch macromolecular components as raw materials. Belonging to the field of graphite material preparation, it addresses the problem of high requirements for process control in graphite production and the inability to simultaneously meet the demands of high-value-added applications in terms of mechanical properties and graphitization degree. The solution is as follows: Macromolecular components, a byproduct of coal tar pitch modification or purification, are selected as raw materials. A self-sintering graphite preparation method is employed. First, the raw materials are preheated at 150-210℃, then crushed to a D50 of 10-50 micrometers to obtain pressed powder. Next, the pressed powder is formed using warm isostatic pressing at a pressure of 70-180 MPa to obtain a green body. Finally, the green body undergoes conventional carbonization and graphitization treatments to obtain graphite materials with simple production process control and mechanical properties and graphitization degree that simultaneously meet the demands of high-value-added applications.

Description

Technical Field

[0001] This invention belongs to the field of graphite material preparation technology, specifically relating to a method for preparing high-density graphite materials using coal tar pitch macromolecular components as raw materials. Background Technology

[0002] With the development of the national economy, the application fields of graphite materials have expanded from traditional fields such as electric brushes and steel smelting to high-value-added fields such as chemical industry, nuclear industry, photovoltaics, electrical discharge machining, and electronic chips. These applications place higher demands on the physical properties of graphite materials, including density, hardness, mechanical properties, thermoelectric properties, and porosity.

[0003] With the improvement of manufacturing capabilities and the enhancement of polymer compound analysis and testing capabilities, research institutions and carbon production enterprises have generally adopted the method of raw material refinement and the addition of binders to improve the performance of graphite materials. However, after the implementation of this method, the market share of graphite materials in new high-value-added fields has not increased significantly. This is due to the following systemic problems with this method: raw material refinement amplifies the short-range disorder in its microstructure, transforming easily graphitizable components into difficult-to-graphitize components. At the same graphitization temperature, this not only increases the product shrinkage rate but also reduces the long-range order of the product, making the sintering difficulty more difficult and the degree of graphitization lower. However, high-value-added fields have comprehensive requirements for graphite materials, demanding not only high mechanical properties but also a higher degree of graphitization. Therefore, there is an urgent need for a high-density graphite material with low production process control requirements and simultaneously meeting the needs of high-value-added industries in terms of mechanical properties and degree of graphitization. Summary of the Invention

[0004] The main objective of this invention is to overcome the shortcomings of the prior art and solve the problems that the production process of graphite products requires high control and that the mechanical properties and graphitization degree cannot simultaneously meet the needs of high-value-added application fields. This invention provides a method for preparing high-density graphite materials using coal tar pitch macromolecular components as raw materials.

[0005] This invention is achieved through the following technical solution: a method for preparing high-density graphite materials using coal tar pitch macromolecular components as raw materials, comprising the following steps:

[0006] S1. Take the macromolecular component obtained during the modification or purification of coal tar pitch as coal tar pitch component A. Take coal tar pitch component A and preheat it in a vacuum oven at a temperature of 150℃-210℃ for 30min-240min. Then crush it to obtain pressed powder B.

[0007] S2. Pack the pressed powder B into the sleeve, evacuate it and put it into the isostatic pressing equipment for isostatic pressing. The isostatic pressing pressure is 70-180MPa and the holding time is 10min. After slowly depressurizing, the green body is formed.

[0008] S3. First, the green blank prepared in step S2 is placed in a carbonization sintering furnace for carbonization treatment. The carbonization temperature is 1200℃, the heating rate from room temperature to the carbonization temperature is 1℃ / h, and the carbonization time is 2h. Then, the carbonized material is taken out and placed in a graphitization furnace for graphitization treatment. The graphitization temperature is 2800℃, the heating rate from the carbonization temperature to the graphitization temperature is 150℃ / h, and the graphitization time is 1h. Both carbonization and graphitization adopt conventional non-impregnation processes to obtain high-density graphite materials.

[0009] Furthermore, in step S1, the quinoline-insoluble content in coal tar pitch component A is ≥97%, the quinoline-insoluble toluene-soluble content is 1.5%-8.5%, and the ash content is ≤0.3%.

[0010] Furthermore, in step S1, the crushing method is mechanical crushing, or high-energy ball milling, or mechanical crushing followed by high-energy ball milling.

[0011] Further, in step S1, the particle size D50 (D50: the particle size corresponding to a cumulative particle size distribution percentage of 50% for a sample. Its physical meaning is that particles larger than it account for 50%, and particles smaller than it also account for 50%. D50 is also called median diameter or median particle size. D50 is often used to represent the average particle size of powder) of 10 micrometers to 50 micrometers.

[0012] Furthermore, the particle size D50 of the pressed powder B is 15 micrometers to 40 micrometers.

[0013] Furthermore, in step S2, isostatic pressing is performed using a warm isostatic press, with the oil temperature of the warm isostatic press being 40℃-90℃.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] 1) Regarding raw material selection, the purpose of coal tar pitch modification and purification is to obtain modified pitch with high β-resin content and controllable softening point, or purified pitch with low impurity content. Among the coal tar pitch components, component A, which has the highest macromolecular content, is often sold and used as a by-product, resulting in low economic benefits. This invention uses by-product component A as raw material, and after simple pretreatment, employs a self-sintering graphite preparation method to prepare graphite materials with high density, high mechanical properties, and high graphitization degree, thereby significantly increasing the added value of the raw materials and generating higher economic benefits.

[0016] 2) In terms of powder preparation, compared with existing improved solutions such as raw material refinement and adding binders, the present invention selects raw material particle size ≥10 micrometers. Since particle size crushing is the most energy-consuming stage in powder preparation, this invention significantly reduces unit energy consumption and further improves economic efficiency.

[0017] 3) In the pressing and subsequent heat treatment stages, the present invention adopts a conventional process scheme, which is not significantly different from the traditional graphite preparation process parameters. This better ensures the operability of the present invention, reduces the risk, and is conducive to research institutions or carbon production enterprises to refine the preparation process scheme in a targeted manner according to their own raw material characteristics and product performance requirements, so that enterprises can obtain the greatest economic benefits with less equipment investment and process adjustment. Detailed Implementation

[0018] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Example 1

[0019] A method for preparing high-density graphite materials using coal tar pitch macromolecular components as raw materials includes the following steps:

[0020] S1. The macromolecular components obtained during the modification or purification of coal tar pitch are taken as coal tar pitch component A. The content of quinoline insoluble matter in coal tar pitch component A is ≥97%, the content of quinoline insoluble toluene soluble matter is 1.5%-8.5%, and the ash content is ≤0.3%. Coal tar pitch component A is preheated in a vacuum oven at a temperature of 150℃ for 120 minutes. After cooling to room temperature, the raw material is crushed to a D50 of 20 micrometers by mechanical crushing to obtain pressed powder B.

[0021] S2. Pack the pressed powder B into a sleeve, evacuate the vacuum, and place it into a warm isostatic press for isostatic pressing. The oil temperature of the warm isostatic press is 40℃-90℃, the isostatic pressure is 150MPa, the holding time is 10min, and the green body is formed after slowly releasing the pressure.

[0022] S3. First, the green body prepared in step S2 is placed in a carbonization sintering furnace for carbonization under nitrogen protection. The carbonization temperature is 1200℃, the heating rate from room temperature to the carbonization temperature is 1℃ / h, and the carbonization time is 2h. Then, the carbonized material is removed and placed in a graphitization furnace for graphitization treatment. The graphitization temperature is 2800℃, the heating rate from the carbonization temperature to the graphitization temperature is 150℃ / h, and the graphitization time is 1h, to obtain high-density graphite material. The performance test results of the high-density graphite material prepared in Example 1 are shown in Table 1. Example 2

[0023] A method for preparing high-density graphite materials using coal tar pitch macromolecular components as raw materials includes the following steps:

[0024] S1. The macromolecular components obtained during the modification or purification of coal tar pitch are taken as coal tar pitch component A. The content of quinoline insoluble matter in coal tar pitch component A is ≥97%, the content of quinoline insoluble toluene soluble matter is 1.5%-8.5%, and the ash content is ≤0.3%. Coal tar pitch component A is preheated in a vacuum oven at a temperature of 180℃ for 60 minutes. After cooling to room temperature, the raw material is crushed to a D50 of 25 microns by mechanical crushing to obtain pressed powder B.

[0025] S2. Pack the pressed powder B into a sleeve, evacuate the vacuum, and place it into a warm isostatic press for isostatic pressing. The oil temperature of the warm isostatic press is 40℃-90℃, the isostatic pressure is 150MPa, the holding time is 10min, and the green body is formed after slowly releasing the pressure.

[0026] S3. First, the green body prepared in step S2 is placed in a carbonization sintering furnace for carbonization under nitrogen protection. The carbonization temperature is 1200℃, the heating rate from room temperature to the carbonization temperature is 1℃ / h, and the carbonization time is 2h. Then, the carbonized material is removed and placed in a graphitization furnace for graphitization treatment. The graphitization temperature is 2800℃, the heating rate from the carbonization temperature to the graphitization temperature is 150℃ / h, and the graphitization time is 1h, thus obtaining a high-density graphite material. The performance test results of the high-density graphite material prepared in Example 2 are shown in Table 1. Example 3

[0027] A method for preparing high-density graphite materials using coal tar pitch macromolecular components as raw materials includes the following steps:

[0028] S1. The macromolecular components obtained during the modification or purification of coal tar pitch are taken as coal tar pitch component A. The content of quinoline insoluble matter in coal tar pitch component A is ≥97%, the content of quinoline insoluble toluene soluble matter is 1.5%-8.5%, and the ash content is ≤0.3%. Coal tar pitch component A is preheated in a vacuum oven at a temperature of 210℃ for 30 minutes. After cooling to room temperature, the raw material is crushed to a D50 of 15 microns by mechanical crushing to obtain pressed powder B.

[0029] S2. Pack the pressed powder B into a sleeve, evacuate the vacuum, and place it into a warm isostatic press for isostatic pressing. The oil temperature of the warm isostatic press is 40℃-90℃, the isostatic pressure is 150MPa, the holding time is 10min, and the green body is formed after slowly releasing the pressure.

[0030] S3. First, the green body prepared in step S2 is placed in a carbonization sintering furnace for carbonization under nitrogen protection. The carbonization temperature is 1200℃, the heating rate from room temperature to the carbonization temperature is 1℃ / h, and the carbonization time is 2h. Then, the carbonized material is removed and placed in a graphitization furnace for graphitization treatment. The graphitization temperature is 2800℃, the heating rate from the carbonization temperature to the graphitization temperature is 150℃ / h, and the graphitization time is 1h, to obtain high-density graphite material. The performance test results of the high-density graphite material prepared in Example 3 are shown in Table 1.

[0031]

[0032] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A method for producing a high-density graphite material from a coal-tar pitch macromolecular component, characterized by, Includes the following steps: S1. The macromolecular components obtained during the modification or purification of coal tar pitch are taken as coal tar pitch component A. The content of quinoline insoluble matter in coal tar pitch component A is ≥97%, the content of quinoline insoluble toluene soluble matter is 1.5%-8.5%, and the ash content is ≤0.3%. Coal tar pitch component A is preheated in a vacuum oven at a temperature of 150℃-210℃ for 30min-240min, and then crushed to obtain pressed powder B. S2. Pack the pressed powder B into the sleeve, evacuate it and put it into the isostatic pressing equipment for isostatic pressing. The isostatic pressing pressure is 70-180MPa and the holding time is 10min. After slowly depressurizing, the green body is formed. S3. First, the green blank prepared in step S2 is placed in a carbonization sintering furnace for carbonization treatment. The carbonization temperature is 1200℃, the heating rate from room temperature to the carbonization temperature is 1℃ / h, and the carbonization time is 2h. Then, the carbonized material is taken out and placed in a graphitization furnace for graphitization treatment. The graphitization temperature is 2800℃, the heating rate from the carbonization temperature to the graphitization temperature is 150℃ / h, and the graphitization time is 1h, to obtain high-density graphite material.

2. The method for preparing high-density graphite material using coal tar pitch macromolecular components as raw materials according to claim 1, wherein in step S1, the crushing method is high-energy ball milling.

3. The method for preparing high-density graphite material using coal tar pitch macromolecular components as raw materials according to claim 1, wherein in step S1, the particle size D50 of the crushed powder B is 10 micrometers to 50 micrometers.

4. The method for preparing high-density graphite material using coal tar pitch macromolecular components as raw materials according to claim 3, wherein the particle size D50 of the pressed powder B is 15 micrometers to 40 micrometers.

5. The method for preparing high-density graphite material using coal tar pitch macromolecular components as raw materials according to claim 1, wherein in step S2, isostatic pressing is performed using a warm isostatic press, and the oil temperature of the warm isostatic press is 40℃-90℃.

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