CN114735691A - Process for purifying high-purity carbon powder - Google Patents
Process for purifying high-purity carbon powder Download PDFInfo
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- CN114735691A CN114735691A CN202210355819.4A CN202210355819A CN114735691A CN 114735691 A CN114735691 A CN 114735691A CN 202210355819 A CN202210355819 A CN 202210355819A CN 114735691 A CN114735691 A CN 114735691A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/21—After-treatment
- C01B32/215—Purification; Recovery or purification of graphite formed in iron making, e.g. kish graphite
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Abstract
The invention provides a process for purifying high-purity carbon powder, which adopts an intermittent treatment mode, and finally finishes material taking by mixing additives into graphite powder, heating, sintering, purifying and cooling, wherein the purity of the obtained carbon powder can reach 99.999 percent, and the content of boron elements is less than 0.01 ppm. The method avoids chlorine and Freon gas adopted in the traditional carbon powder purification, has high requirement on equipment, causes air pollution and influences human health due to the added chlorine and Freon, does not cause environmental pollution in the carbon powder purification process, is simple to operate, can greatly reduce the production cost, meets the purity requirement and removes impurities.
Description
Technical Field
The invention belongs to the technical field of metal smelting, and relates to a process for purifying high-purity carbon powder.
Background
The third generation semiconductor crystal garden uses silicon carbide as substrate material, the high purity silicon carbide powder is made of high purity carbon powder and high purity silicon powder, the high purity carbon powder is required to reach more than 99.999%, the content of trace impurity elements is less than 0.01ppm, many suppliers in China adopt acid-base method of adding Freon, chlorine and the like to purify the carbon powder in order to improve the purity of the carbon powder and reduce the impurity content, the method is not only expensive in cost, but also easily causes serious pollution to the atmospheric environment, therefore, the invention provides a process for purifying the high purity carbon powder to solve the problems.
Disclosure of Invention
The invention aims to provide a process for purifying high-purity carbon powder aiming at the problems in the prior art, and can solve the problems that the existing carbon powder purification mode is high in cost, easy to cause atmospheric environmental pollution and poor in purification effect.
Therefore, the invention adopts the following technical scheme:
a process for purifying high purity carbon powder comprising the steps of:
a. crushing the massive graphite to the granularity of 400-500 meshes, adding halogen complex salt according to the proportion of 1:0.2, and uniformly stirring;
b. pouring the mixture obtained in the step b into a purification furnace, sequentially starting a vacuum pump and an air extraction valve to begin to vacuumize the purification furnace, and closing the vacuum pump and the air extraction valve until the vacuum degree is-320 Pa;
c. opening an air inlet valve to fill argon into the purification furnace, starting to heat materials in the furnace until the negative pressure in the furnace is 0-1Pa, and opening an exhaust valve;
d. heating to 2400 deg.C, maintaining the temperature for 1 hr, and continuing heating to 2800-;
e. and naturally cooling the material in the purifying furnace after the second heat preservation is finished, closing an air inlet valve and an air outlet valve of the purifying furnace when the furnace temperature is cooled to 1000 ℃, and continuously performing natural cooling.
And furthermore, in the step d, the argon is continuously filled into the purification furnace in the process of purification, and the pressure in the furnace is ensured to be 0-1Pa all the time.
Further, the halogen complex salt in the step a is sodium hexafluorophosphate NaPF 6.
The invention has the beneficial effects that:
according to the invention, a halogen complex salt is added in the carbon powder purification process, the purity of the obtained carbon powder can reach more than 99.999%, and the content of the impurity boron elements is less than 0.01ppm, so that the problems of air pollution and influence on human health caused by chlorine and Freon gas adopted in the traditional carbon powder purification can be avoided, meanwhile, the operation is simple, the production cost can be greatly reduced, the requirement on the purity of the carbon powder is met, and the impurities are removed.
Detailed Description
The technical solution of the present invention will be described below with reference to the implementation methods.
Example 1
A process for purifying high purity carbon powder comprising the steps of:
a. crushing the massive graphite to the granularity of 400-500 meshes, adding halogen complex salt such as sodium hexafluorophosphate NaPF6 according to the proportion of 1:0.2, and uniformly stirring;
b. pouring the mixture obtained in the step b into a purification furnace, sequentially starting a vacuum pump and an air extraction valve to begin to vacuumize the purification furnace, and closing the vacuum pump and the air extraction valve until the vacuum degree is-320 Pa;
c. opening an air inlet valve to fill argon into the furnace, starting to heat materials in the furnace until the negative pressure in the furnace is 0-1Pa, and opening an exhaust valve;
d. heating to 2400 deg.C, maintaining the temperature for 1 hr, and continuing heating to 2800-;
e. and naturally cooling the material in the purifying furnace after the heat preservation is finished, closing an air inlet valve and an air outlet valve of the purifying furnace when the furnace temperature is cooled to 1000 ℃, and continuously performing natural cooling. And taking out the crucible when the temperature is reduced to the room temperature, and bagging the powder.
Compared with the carbon powder purity of 99.9996% and the boron element content of 0.6ppm in the carbon powder raw material to be purified, the carbon powder purity of 99.9996% and the boron element content of 0.2ppm in the material obtained in step e in embodiment 1, and compared with the carbon powder raw material to be purified, the boron element content is reduced by 0.4 ppm.
Example 2
A process for purifying high purity carbon powder comprising the steps of:
a. crushing the massive graphite to the granularity of 400-500 meshes, adding halogen complex salt such as sodium hexafluorophosphate NaPF6 according to the proportion of 1:0.35, and uniformly stirring;
b. pouring the mixture obtained in the step b into a purification furnace, sequentially starting a vacuum pump and an air extraction valve to begin to vacuumize the purification furnace, and closing the vacuum pump and the air extraction valve until the vacuum degree is-320 Pa;
c. opening an air inlet valve to fill argon into the furnace, starting to heat materials in the furnace until the negative pressure in the furnace is 0-1Pa, and opening an exhaust valve;
d. heating to 2400 deg.C, maintaining the temperature for 1 hr, and continuing heating to 2800-;
e. and naturally cooling the material in the purifying furnace after the heat preservation is finished, closing an air inlet valve and an air outlet valve of the purifying furnace when the material is cooled to the temperature of 1000 ℃, and continuously performing natural cooling. And taking out the crucible when the temperature is reduced to the room temperature, and bagging the powder.
Compared with the carbon powder purity of 99.9996% and the boron element content of 0.6ppm in the carbon powder raw material to be purified, the carbon powder purity of 99.9997% and the boron element content of 0.07ppm in the material obtained in the step e in the embodiment 2, and the boron element content is reduced by 0.53ppm compared with the carbon powder raw material to be purified.
Example 3
A process for purifying high purity carbon powder comprising the steps of:
a. crushing the massive graphite to the granularity of 400-500 meshes, adding halogen complex salt such as sodium hexafluorophosphate NaPF6 according to the proportion of 1:0.5, and uniformly stirring;
b. pouring the mixture obtained in the step b into a purification furnace, sequentially starting a vacuum pump and an air extraction valve to begin to vacuumize the purification furnace, and closing the vacuum pump and the air extraction valve until the vacuum degree is-320 Pa;
c. opening an air inlet valve to fill argon into the furnace, starting to heat materials in the furnace until the negative pressure in the furnace is 0-1Pa, and opening an exhaust valve;
d. heating to 2400 deg.C, maintaining the temperature for 1 hr, and continuing heating to 2800-;
e. and naturally cooling the material in the purifying furnace after the heat preservation is finished, closing an air inlet valve and an air outlet valve of the purifying furnace when the furnace temperature is cooled to 1000 ℃, and continuously performing natural cooling. And taking out the crucible when the temperature is reduced to the room temperature, and bagging the powder.
Compared with the carbon powder purity of 99.9996% and boron element content of 0.6ppm in the carbon powder raw material to be purified, the carbon powder purity of 99.9999% and boron element content of <0.01ppm in the material obtained in the step e in the embodiment 3, and compared with the carbon powder raw material to be purified, the boron element content is reduced by at least 0.59 ppm.
Claims (3)
1. A process for purifying high purity carbon powder, comprising the steps of:
a. crushing the massive graphite to the granularity of 400-500 meshes, adding halogen complex salt according to the proportion of 1:0.2, and uniformly stirring;
b. pouring the mixture obtained in the step b into a purification furnace, sequentially starting a vacuum pump and an air extraction valve to begin to vacuumize the purification furnace, and closing the vacuum pump and the air extraction valve until the vacuum degree is-320 Pa;
c. opening an air inlet valve to fill argon into the purification furnace, starting to heat materials in the furnace until the negative pressure in the furnace is 0-1Pa, and opening an exhaust valve;
d. heating to 2400 deg.C, maintaining the temperature for 1 hr, and continuing heating to 2800-;
e. and naturally cooling the material in the purifying furnace after the second heat preservation is finished, closing an air inlet valve and an air outlet valve of the purifying furnace when the furnace temperature is cooled to 1000 ℃, and continuously performing natural cooling.
2. A process for purifying high purity carbon powder according to claim 1 wherein the argon is continuously introduced into the purification furnace during the step d, and the pressure in the furnace is always kept at 0-1 Pa.
3. A process for purifying high purity carbon powder according to claim 1 wherein the halogen complex salt in step a is sodium hexafluorophosphate NaPF 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202210355819.4A CN114735691A (en) | 2022-04-06 | 2022-04-06 | Process for purifying high-purity carbon powder |
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| CN202210355819.4A CN114735691A (en) | 2022-04-06 | 2022-04-06 | Process for purifying high-purity carbon powder |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116675228A (en) * | 2023-08-03 | 2023-09-01 | 苏州优晶光电科技有限公司 | Raw material purification method and raw material for silicon carbide single crystal growth |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102105394A (en) * | 2008-08-08 | 2011-06-22 | 斯泰拉化工公司 | Processes for production of phosphorus pentafluoride and hexafluorophosphates |
| CN102421702A (en) * | 2009-03-13 | 2012-04-18 | 霍尼韦尔国际公司 | Methods and reactor designs for producing phosphorus pentafluoride |
| CN107619028A (en) * | 2017-09-16 | 2018-01-23 | 广东金光高科股份有限公司 | Phosphorus pentafluoride high efficiency continuously synthesizer and technique |
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2022
- 2022-04-06 CN CN202210355819.4A patent/CN114735691A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102105394A (en) * | 2008-08-08 | 2011-06-22 | 斯泰拉化工公司 | Processes for production of phosphorus pentafluoride and hexafluorophosphates |
| CN102421702A (en) * | 2009-03-13 | 2012-04-18 | 霍尼韦尔国际公司 | Methods and reactor designs for producing phosphorus pentafluoride |
| CN107619028A (en) * | 2017-09-16 | 2018-01-23 | 广东金光高科股份有限公司 | Phosphorus pentafluoride high efficiency continuously synthesizer and technique |
Non-Patent Citations (1)
| Title |
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| 申泮文: "《化合物词典》", 上海辞书出版社, pages: 52 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116675228A (en) * | 2023-08-03 | 2023-09-01 | 苏州优晶光电科技有限公司 | Raw material purification method and raw material for silicon carbide single crystal growth |
| CN116675228B (en) * | 2023-08-03 | 2023-10-20 | 苏州优晶光电科技有限公司 | Raw material purification method and raw material for silicon carbide single crystal growth |
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