CN115744899A - Preparation method of expanded graphite - Google Patents
Preparation method of expanded graphite Download PDFInfo
- Publication number
- CN115744899A CN115744899A CN202211470516.3A CN202211470516A CN115744899A CN 115744899 A CN115744899 A CN 115744899A CN 202211470516 A CN202211470516 A CN 202211470516A CN 115744899 A CN115744899 A CN 115744899A
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- Prior art keywords
- graphite
- expanded graphite
- preparation
- pressure
- expanded
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 74
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 73
- 239000010439 graphite Substances 0.000 title claims abstract description 73
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- -1 1-butyl-3-methylimidazole hexafluorophosphate Chemical compound 0.000 claims abstract description 9
- 239000002608 ionic liquid Substances 0.000 claims abstract description 9
- 229910021382 natural graphite Inorganic materials 0.000 claims abstract description 9
- 238000001035 drying Methods 0.000 claims abstract description 8
- 238000002156 mixing Methods 0.000 claims abstract description 6
- 238000003756 stirring Methods 0.000 claims abstract description 6
- 238000007789 sealing Methods 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 16
- 230000008569 process Effects 0.000 claims description 6
- 238000004321 preservation Methods 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims 1
- 239000000126 substance Substances 0.000 abstract description 8
- 230000007613 environmental effect Effects 0.000 abstract description 4
- 239000002699 waste material Substances 0.000 abstract description 4
- 239000002253 acid Substances 0.000 abstract description 3
- 239000002994 raw material Substances 0.000 abstract description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 abstract description 2
- 230000008859 change Effects 0.000 abstract description 2
- 238000004146 energy storage Methods 0.000 abstract description 2
- 239000000945 filler Substances 0.000 abstract description 2
- 238000009413 insulation Methods 0.000 abstract description 2
- 239000003566 sealing material Substances 0.000 abstract description 2
- 239000011232 storage material Substances 0.000 abstract description 2
- 239000011593 sulfur Substances 0.000 abstract description 2
- 229910052717 sulfur Inorganic materials 0.000 abstract description 2
- 239000011229 interlayer Substances 0.000 description 5
- 239000010410 layer Substances 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 3
- 239000007800 oxidant agent Substances 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 238000005411 Van der Waals force Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000006056 electrooxidation reaction Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- VKJKEPKFPUWCAS-UHFFFAOYSA-M potassium chlorate Chemical compound [K+].[O-]Cl(=O)=O VKJKEPKFPUWCAS-UHFFFAOYSA-M 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Classifications
-
- 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
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
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- Carbon And Carbon Compounds (AREA)
Abstract
The invention relates to a preparation method of expanded graphite, which is characterized by comprising the following steps: (1) mixing natural graphite and ionic liquid according to a mass ratio of 1:1-3, fully stirring uniformly, separating and drying to obtain graphite A, wherein the ionic liquid is 1-butyl-3-methylimidazole hexafluorophosphate or 1-butyl-3-methylimidazole tetrafluoroborate; (2) Placing the graphite A in a high-temperature high-pressure container, sealing and insulating at 100-250 deg.C under 10-100Mpa for 0.5-2h, quickly opening the pressure release valve after the insulation is finished, and instantly releasing pressure to obtain the expanded graphite. The invention has the advantages that: the preparation method disclosed by the invention has the advantages of easiness in obtaining raw materials, short preparation flow, simplicity in operation, greenness and environmental friendliness in the whole preparation process, capability of effectively avoiding the use of strong-oxidizing and strong-acid substances and no generation of three wastes; the prepared expanded graphite has the expansion volume of 50-200mL/g, does not contain sulfur, and can be used for sealing materials, fireproof fillers, phase change energy storage materials and the like.
Description
Technical Field
The invention belongs to the field of new material preparation, and relates to a preparation method of expanded graphite.
Background
The existing expanded graphite is prepared by using natural crystalline flake graphite as a raw material, preparing a mixed solution by using concentrated sulfuric acid, concentrated nitric acid, potassium chlorate or similar strong oxidants to treat the natural crystalline flake graphite to form an interlayer compound, then heating the interlayer compound at a high temperature (such as 950 ℃) for 10 to 20 seconds, vaporizing an insert in the interlayer compound at the high temperature, and flushing a graphite layer, so that the graphite interlayer compound is expanded to form the expanded graphite. The expanded graphite sheet has excellent properties and can be used for sealing members, heat conductive materials and the like. However, these conventional preparation methods use a large amount of strong acid and strong oxidant, and the treatment cost and difficulty of the reaction waste liquid are high, which causes great environmental protection pressure.
Disclosure of Invention
The invention aims to solve the defects of the prior art and provides a preparation method of expanded graphite; the invention prepares the expanded graphite by changing the pressure difference between the inside and the outside of the graphite layer by suddenly changing the environmental pressure field, so that the graphite sheet layers are separated and the interlayer spacing is enlarged.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a preparation method of expanded graphite is characterized by comprising the following steps:
(1) Mixing natural graphite and ionic liquid according to a mass ratio of 1:1-3, fully stirring uniformly (0.5-2 h), separating, and drying (drying at 105-120 ℃ for 1-4 h) to obtain graphite A, wherein the ionic liquid is 1-butyl-3-methylimidazole hexafluorophosphate or 1-butyl-3-methylimidazole tetrafluoroborate;
(2) Placing the graphite A in a high-temperature high-pressure container, sealing and insulating at 100-250 deg.C under 10-100Mpa for 0.5-2h, quickly opening the pressure release valve after the insulation is finished, and instantly releasing pressure to obtain the expanded graphite.
Further, the natural graphite is flake graphite.
Furthermore, the mesh number of the natural graphite is 50-400 meshes.
Furthermore, the mesh number of the natural graphite is 100-300 meshes.
Further, the pressurizing mode in the step (2) is an air-entrapping method.
Further, in the gas filling method, the gas is steam and CO 2 、N 2 And so on.
Further, the expanded graphite has an expanded volume of 50 to 200mL/g.
Through the intensive research on the structure and the property of the natural crystalline flake graphite, the inventor finds that the expansion mechanism of the natural crystalline flake graphite is that substances in graphite layers are heated and quickly gasified to generate pressure to push away graphite sheets, so that the graphite sheets are partially separated and partially combined to obtain the expanded graphite. The method comprises the steps of mixing ionic liquid with natural flake graphite (the surface tension of the ionic liquid is matched with the surface energy of the graphite flakes, the van der Waals force among the graphite flakes can be destroyed by the interaction between the ionic liquid and the natural flake graphite, meanwhile, anions have the functions of dipping and swelling on the structure of the graphite flakes, so that subsequent gas can enter the graphite flakes), placing the modified graphite in a high-pressure field, maintaining the internal and external gas pressure between the graphite flakes for enough time after the internal and external gas pressure is balanced under the action of proper heat preservation, suddenly releasing the pressure, enabling the pressure between the graphite flakes to be far higher than the external pressure, and enabling the graphite flakes to be partially separated under the pressure difference to obtain the expanded graphite.
Compared with the prior art, the invention has the following advantages:
at present, graphite intercalation substances are generally chemical substances inserted between graphite layers by a chemical oxidation method or an electrochemical oxidation method. These substances have strong oxidizing property or strong acidity, which not only generate a large amount of three wastes in the production process, but also remain strong oxidizing and strong acidic substances in the obtained expandable graphite and expanded graphite, so that the application process is greatly limited. The preparation method disclosed by the invention has the advantages of easily available raw materials, short preparation flow, simplicity in operation, greenness and environmental friendliness in the whole preparation process, effectively avoids the use of strong-oxidizing and strong-acid substances, and does not generate three wastes; the prepared expanded graphite has the expansion volume of 50-200mL/g, does not contain sulfur, and can be used for sealing materials, fireproof fillers, phase change energy storage materials and the like.
Detailed Description
The preparation method of the expanded graphite comprises the following specific implementation steps:
example 1
(1) Mixing 5g of 150-mesh crystalline flake graphite and 10g of 1-butyl-3-methylimidazole hexafluorophosphate, fully stirring for 1h, separating, and drying at 120 ℃ for 1.5h to obtain 4.6g of graphite A;
(2) And (3) placing 3g of graphite A in a high-temperature high-pressure container, pressurizing to 50Mpa at 200 ℃, keeping the temperature for 1h in a closed state, quickly opening a pressure release valve after the temperature is kept, and instantly releasing the pressure to obtain the expanded graphite (the expansion volume is 125 mL/g).
Example 2
(1) Mixing 6g of 50-mesh crystalline flake graphite and 15g of 1-butyl-3-methylimidazolium hexafluorophosphate, fully stirring for 2h, separating, and drying at 110 ℃ for 2h to obtain 5.4g of graphite A;
(2) And (3) placing 3g of graphite A in a high-temperature high-pressure container, pressurizing to 20Mpa at 120 ℃, keeping the temperature for 0.5h in a closed state, quickly opening a pressure release valve after the temperature is kept, and instantly releasing the pressure to obtain the expanded graphite (the expansion volume is 200 mL/g).
Example 3
(1) 8g of 200-mesh crystalline flake graphite and 8g of 1-butyl-3-methylimidazole tetrafluoroborate are mixed, fully stirred for 1.5h, separated and dried at 105 ℃ for 4h to obtain 7.1g of graphite A;
(2) And (3) placing 5g of graphite A in a high-temperature high-pressure container, pressurizing to 70Mpa at 150 ℃, keeping the temperature for 1.5h in a closed state, quickly opening a pressure release valve after the temperature is kept, and instantly releasing the pressure to obtain the expanded graphite (the expansion volume is 85 mL/g).
Claims (9)
1. A preparation method of expanded graphite is characterized by comprising the following steps:
(1) Mixing natural graphite and ionic liquid according to a mass ratio of 1:1-3, fully stirring uniformly, separating and drying to obtain graphite A, wherein the ionic liquid is 1-butyl-3-methylimidazole hexafluorophosphate or 1-butyl-3-methylimidazole tetrafluoroborate;
(2) And (3) placing the graphite A in a high-temperature high-pressure container, sealing and preserving heat for 0.5-2h at the temperature of 100-250 ℃ under 10-100Mpa, quickly opening a pressure release valve after heat preservation is finished, and instantly releasing pressure to obtain the expanded graphite.
2. The process for producing expanded graphite according to claim 1, wherein: the natural graphite is flake graphite.
3. The method for preparing expanded graphite according to claim 1, wherein: the mesh number of the natural graphite is 50-400 meshes.
4. The process for producing expanded graphite according to claim 3, wherein: the mesh number of the natural graphite is 100-300 meshes.
5. The method for preparing expanded graphite according to claim 1, wherein: the drying temperature is 105-120 ℃, and the drying time is 1-4h.
6. The method for preparing expanded graphite according to claim 1, wherein: the stirring time in the step (1) is 0.5-2h.
7. The process for producing expanded graphite according to claim 1, wherein: the pressurizing mode in the step (2) is an air-entrapping method.
8. The process for producing expanded graphite according to claim 7, wherein: the gas in the gas-adding method is water vapor and CO 2 、N 2 。
9. The process for producing expanded graphite according to any one of claims 1 to 8, wherein: the expanded volume of the expanded graphite is 50-200mL/g.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211470516.3A CN115744899A (en) | 2022-11-23 | 2022-11-23 | Preparation method of expanded graphite |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211470516.3A CN115744899A (en) | 2022-11-23 | 2022-11-23 | Preparation method of expanded graphite |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115744899A true CN115744899A (en) | 2023-03-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211470516.3A Pending CN115744899A (en) | 2022-11-23 | 2022-11-23 | Preparation method of expanded graphite |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115744899A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102616771A (en) * | 2012-03-31 | 2012-08-01 | 黑龙江科技学院 | Method for preparing sulfur-free low-ash expanded graphite |
| CN103663428A (en) * | 2012-09-24 | 2014-03-26 | 海洋王照明科技股份有限公司 | Preparation method of graphene |
| WO2015131933A1 (en) * | 2014-03-05 | 2015-09-11 | Westfälische Wilhelms-Universität Münster | Method of producing graphene by exfoliation of graphite |
| CN107417937A (en) * | 2017-08-21 | 2017-12-01 | 山东圣泉新材料股份有限公司 | A kind of graphene modified cellulose film and preparation method thereof |
-
2022
- 2022-11-23 CN CN202211470516.3A patent/CN115744899A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102616771A (en) * | 2012-03-31 | 2012-08-01 | 黑龙江科技学院 | Method for preparing sulfur-free low-ash expanded graphite |
| CN103663428A (en) * | 2012-09-24 | 2014-03-26 | 海洋王照明科技股份有限公司 | Preparation method of graphene |
| WO2015131933A1 (en) * | 2014-03-05 | 2015-09-11 | Westfälische Wilhelms-Universität Münster | Method of producing graphene by exfoliation of graphite |
| CN107417937A (en) * | 2017-08-21 | 2017-12-01 | 山东圣泉新材料股份有限公司 | A kind of graphene modified cellulose film and preparation method thereof |
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