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Method for preparing isotropic graphite containing coal-based needle coke as aggregate

An isotropic, needle coke technology, applied in the field of isotropic graphite preparation, can solve the problems of limited sources and high cost of raw materials

Inactive Publication Date: 2012-06-20
UNIV OF SHANGHAI FOR SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The raw materials used in the above patents are either graphite or mesophase carbon microspheres, and the cost of raw materials is high and the source is limited.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The coal tar pitch binder with a mass ratio of 0.2:1 and the needle coke aggregate were uniformly mixed in a kneader, then crushed by a mechanical pulverizer, and then formed and carbonized by a hot isostatic pressing machine. The hot isostatic pressing pressure was 100Mpa, the molding temperature is 1000°C, and the molding time is 5 hours. After the molding is completed, it is impregnated and roasted again. When impregnating, first vacuum the impregnating system to below 50Pa, then heat the asphalt to melt and introduce it, impregnate at 0.5Mpa, and hold the pressure for 1 hour. After impregnation The temperature for firing is 1000°C for 10 hours. Finally, it is graphitized again, wherein the graphitization temperature is 2200° C., the heating rate is 5° C. / min, and the temperature is kept for 1 hour.

[0017] Gained graphite product has a bulk density of 1.84g / cm 3 , anisotropy index 1.03, compressive strength 60Mpa, ash content 150ppm.

Embodiment 2

[0019] The coal tar pitch binder with a mass ratio of 0.4:1 and the needle coke aggregate were uniformly mixed in a kneader, then crushed by a mechanical pulverizer, and then carbonized by a hot isostatic pressing machine. The hot isostatic pressing pressure was 80Mpa, the molding temperature is 800°C, and the molding time is 4 hours. After the molding is completed, it is impregnated and roasted again. When impregnating, first vacuum the impregnating system to below 50Pa, then heat the asphalt to melt and introduce it, impregnate at 1Mpa, impregnate and hold the pressure for 1 hour, and then carry out after impregnation. The roasting temperature is 800°C, roasting for 20 hours, after the completion of the second impregnation and roasting, the conditions are the same as the first time, and finally, it is graphitized, the graphitization temperature is 2200°C, and the heating rate is 5°C / min, keep warm for 1 hour.

[0020] Gained graphite product has a bulk density of 1.83g / cm ...

Embodiment 3

[0022] The petroleum asphalt binder with a mass ratio of 0.3:1 and the needle coke aggregate were uniformly mixed in a kneader, then crushed by a mechanical pulverizer, and then formed and carbonized by a hot isostatic pressing machine. The hot isostatic pressing pressure was 100Mpa, the molding temperature is 1000°C, and the molding time is 5 hours. After the molding is completed, it is impregnated and roasted again. When impregnating, first vacuum the impregnating system to below 50Pa, then heat the asphalt to melt and introduce it, impregnate at 1Mpa, impregnate and hold the pressure for 1 hour, and then carry out after impregnation. The roasting temperature is 1000°C for 40 hours. After the end, it is impregnated and roasted for the second time. The conditions are the same as the first time. Finally, it is graphitized. The graphitization temperature is 3000°C and the heating rate is 10°C / min, keep warm for 0.5 hours.

[0023] Gained graphite product has a bulk density of ...

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Abstract

The invention discloses a method for preparing isotropic graphite containing coal-based needle coke as aggregate. The method comprises the following steps of: firstly, thoroughly mixing binders and aggregates at a weight ratio of (0.2 to 0.6):1 in the form of kneading under the condition of being higher than the softening point of the binder; performing cold isostatic pressing on the mixture and then charring to obtain a biscuit-firing product under such conditions that the cold isostatic pressing pressure is 100 to 200 Mpa and the charring temperature is 800 DEG C to 1000 DEG C; putting the product in a container, feeding an impregnant (i.e. asphalt), evacuating the impregnation system until the pressure is below 500 Pa, introducing molten asphalt, impregnating under 0.5 to 1.5 Mpa and maintaining for 1 hour, and calcining at 500 DEG C to 1000 DEG C; and putting the resulting product in a graphitizing furnace, performing graphitizing treatment at 2200 DEG C to 3000 DEG C and maintaining for 0.5 to 1 hour. The method has the advantages of easily-accessible raw material, high yield and low cost; and the product is advantageous in high graphitization degree, low volatile component and ash contents, high compression strength and good isotropic indexes.

Description

technical field [0001] The invention relates to a method for preparing isotropic graphite with coal needle coke as aggregate. Background technique [0002] As an important material, high-density and high-strength isotropic graphite can be used in special working conditions such as high temperature and high radiation. It has been considered as an irreplaceable necessary material in some occasions, such as aluminum and aluminum alloys and continuous Continuous casting graphite for cast iron, graphite for medium and high-grade EDM, fine particle isotropic graphite for Czochralski single crystal furnace, isotropic graphite for optical fiber preform, graphite for nuclear reactor, etc. In these fields, isotropic Graphite has the advantages of good isotropy, high material density, high mechanical strength, strong oxidation resistance, good radiation resistance and stable chemical properties. [0003] There are usually two methods for the preparation of isotropic graphite. One is t...

Claims

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Application Information

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IPC IPC(8): C01B31/04C01B32/205
Inventor 杨光智李冬锋邱汉迅何星张慧娟杨俊和
Owner UNIV OF SHANGHAI FOR SCI & TECH
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