CN113816371B - Method for preparing expandable graphite through freeze-drying - Google Patents
Method for preparing expandable graphite through freeze-drying Download PDFInfo
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- CN113816371B CN113816371B CN202111124850.9A CN202111124850A CN113816371B CN 113816371 B CN113816371 B CN 113816371B CN 202111124850 A CN202111124850 A CN 202111124850A CN 113816371 B CN113816371 B CN 113816371B
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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
- C01B32/22—Intercalation
- C01B32/225—Expansion; Exfoliation
Abstract
The invention relates to a preparation method of expandable graphite, which is characterized by comprising the following steps: (1) Adding an oxidant into natural crystalline flake graphite, reacting for 30-180min, washing with deionized water for 3-5 times, and then drying at 35-65 ℃ for 2.5-3.5h; (2) Adding ammonium bicarbonate into deionized water at 30-50 ℃ to prepare supersaturated ammonium bicarbonate solution; (3) the volume ratio is 1:2-5, placing the graphite oxide prepared in the step (1) into supersaturated ammonium bicarbonate solution, placing into a closed container filled with carbon dioxide, uniformly mixing, and placing into ice water bath for ultrasonic treatment for 5-60min; (4) Transferring the powder into a freezer with the temperature of minus 15 to minus 20 ℃ after ultrasonic treatment, and then placing the powder into a vacuum freeze drying oven with the temperature of minus 55 to minus 65 ℃ for freeze drying; (5) Sieving to remove non-intercalated ammonium bicarbonate, and hermetically storing at a low temperature of-18-10 ℃; (6) And puffing the intercalated graphite at the temperature of 300-900 ℃. The invention has the advantages that: the reaction is mild and the operation is safe; the product is nontoxic and pollution-free, has good quality, and meets the use requirement of the high-end field.
Description
Technical Field
The invention belongs to the technical field of graphite preparation, and particularly relates to a method for preparing expandable graphite by freeze-drying.
Background
The expanded graphite is a loose and porous vermiform substance prepared from natural crystalline flake graphite, and is a graphite interlayer compound obtained by inserting foreign substances with properties different from graphite into graphite sheets by a physical or chemical method, and the interlayer compound is instantaneously decomposed and gasified under the action of heat or microwaves, so that the loose and porous vermiform substance, namely the expanded graphite, is formed.
The expanded graphite material has light weight, large specific surface area, porosity, good oxidation resistance and strong adsorption capacity, and the expanded graphite materials can be mutually meshed by themselves and are mutually bonded by only mechanical pressurization. With the rapid development of modern industry, especially the rising of new industries such as energy conservation, environmental protection, new energy materials, new generation information technology, high-end equipment manufacturing, biomedical treatment, aerospace and the like, the requirements on engineering materials are higher and higher. In recent years, the practice shows that the expanded graphite and the composite material taking the expanded graphite as the matrix can meet various industrial requirements, and have extremely wide research and application prospects.
At present, various preparation methods of the expanded graphite mainly comprise a chemical oxidation method, an electrochemical method, a weather diffusion method, a mixed liquid phase method, a melting method, a pressurizing method and the like; the chemical oxidation method is a main method for preparing the expandable graphite at home and abroad, and the process route is mature. But due to strong oxidants (KMnO 4 、K 2 CrO 7 、NaNO 3 、KClO 4 、(NH 4 ) 2 S 2 、HClO 4 、H 2 O 2 、HNO 3 Etc.) and strong acids (H 2 SO 4 、HClO 4 、HNO 3 、H 3 P0 4 Etc.), the preparation process is fierce, the danger is high, and the working condition of workers is poor; the use of heavy metal oxidant causes serious pollution to the environment; meanwhile, concentrated sulfuric acid is mostly adopted as a reaction medium in the method, so that the sulfur content of the prepared product is too high, and the sealing material prepared by the product is easy to corrode.
Disclosure of Invention
The invention aims to solve the problems of dangerous reaction process, large pollution, high energy consumption, more product impurities, uncontrollable product types, difficult treatment and the like in the existing process of preparing expandable graphite by a chemical oxidation method.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a method for preparing expandable graphite, which is characterized by comprising the following steps:
(1) Adding an oxidant (potassium permanganate or hydrogen peroxide) into natural crystalline flake graphite, fully reacting for 30-180min, oxidizing, fully washing with deionized water for 3-5 times, cleaning the oxidant, and drying at 35-65 ℃ for 2.5-3.5h at constant temperature;
(2) Adding ammonium bicarbonate into deionized water at a constant temperature of 30-50 ℃, and continuously stirring until insoluble phenomenon appears, and preparing supersaturated ammonium bicarbonate solution;
(3) Weighing graphite oxide prepared in the step (1), putting the graphite oxide into the supersaturated ammonium bicarbonate solution in the step (2), and controlling the volume ratio of the graphite oxide to the ammonium carbonate solution to be 1:2-5, putting the mixture into a closed container filled with carbon dioxide, fully and uniformly mixing, and performing ultrasonic treatment in an ice water bath for 5-60min;
(4) Rapidly transferring the mixture to a freezing box at the temperature of minus 15 to minus 20 ℃ after the ultrasonic treatment is finished, fully freezing the mixture, and placing the frozen mixture into a vacuum freeze drying box at the temperature of minus 55 to minus 65 ℃ until the freeze drying is finished;
(5) Placing the dried substance into a sieve, slightly shaking to separate graphite oxide from non-intercalated ammonium bicarbonate, and immediately sealing and preserving at low temperature (-18-10 ℃) after separation;
(6) And puffing the intercalated graphite at the temperature of 300-900 ℃ to obtain the expanded graphite.
Further, the mass ratio of the graphite to the oxidant potassium permanganate is 1:0.2-1.
Further, the mass ratio of the graphite to the oxidant hydrogen peroxide is 1:1-10.
According to the method, potassium permanganate/hydrogen peroxide is used as an oxidant, and natural graphite is pre-oxidized by a strong oxidant, so that the interlayer spacing of the graphite is increased, and intercalation substances are more facilitated to enter; and (3) preparing supersaturated solution at 30-60 ℃ by taking ammonium bicarbonate as an intercalation agent and utilizing the difference of solubility, promoting the saturated solution to enter graphite layers by ultrasonic waves at low temperature (0-10 ℃), carrying out preliminary recrystallization, continuously reducing the temperature (-18-0 ℃) to promote the recrystallization of ammonium bicarbonate among the graphite layers, and increasing the amount of intercalation substances among the layers.
The beneficial effects of the invention are as follows:
1. potassium permanganate and hydrogen peroxide are used as oxidizing agents, the reaction is mild, the operation is safe (the whole reaction process has no severe chemical reaction and no strong corrosive substances, and the reaction is carried out at low temperature, so that the safety is high-energy); the residual oxidant can be removed by washing and can be recycled by a certain treatment, so that pollution is effectively reduced; ammonia bicarbonate can be decomposed at low temperature, the decomposition products are ammonia gas, carbon dioxide and water, the products are nontoxic and pollution-free, and the products can be directly absorbed by water and ammonia water and recycled;
2. the product quality is good, and the expansion performance of the expansion performance product can be controlled by controlling different oxidation degrees and the entering amount of intercalation substances; after expansion is finished, no intercalation substance residue and no metal oxide residue exist, so that the use is safer, and the use requirements of the high-end field are met.
Description of the drawings
FIG. 1 is a schematic diagram of an oxidation step;
FIG. 2 is a schematic diagram of the washing step after the oxidation is completed;
FIG. 3 is a schematic diagram of an oxidant recycling step;
FIG. 4 is a schematic illustration of an intercalation step for supersaturated ammonium bicarbonate solution.
As can be seen from FIGS. 1-4, the reaction is mild in the preparation process, no severe chemical reaction exists, the method can be operated at low temperature, and the oxidant can be recycled.
Detailed Description
The preparation method of the expandable graphite comprises the following specific implementation steps:
example 1
(1) Adding 0.5g of potassium permanganate into 3g of natural crystalline flake graphite, adding 10mml of deionized water, and fully reacting for 2 hours by ultrasonic oscillation to oxidize the mixture;
(2) Washing the reaction with deionized water for 3 times, clarifying the washing liquid, and drying the washed natural graphite in a constant temperature drying oven at 60 ℃ for 2 hours to obtain graphite oxide;
(3) Adding ammonium bicarbonate into 10ml of water at a constant temperature of 40 ℃ until the phenomenon of insolubility occurs, and preparing supersaturated ammonium bicarbonate solution;
(4) Placing 3g of dried graphite oxide into 10ml of prepared supersaturated ammonium bicarbonate solution, fully and uniformly mixing, transferring into a closed container with a buffer air bag filled with carbon dioxide as a closed condition, fully and uniformly mixing, carrying out ultrasonic treatment in an ice water bath for 30min, quickly transferring into a freezer (-18 ℃) after ultrasonic treatment is finished, fully freezing, placing frozen mixed substances into a vacuum freeze-drying oven (-60 ℃) until freeze-drying is finished, and carrying out simple screening on the dried substances to separate the non-intercalated ammonium bicarbonate from the intercalated graphite, and immediately sealing and storing at low temperature after separation is finished;
(5) Puffing the intercalated graphite at 400 ℃.
Example 2
(1) Adding 10ml hydrogen peroxide into 3g of natural crystalline flake graphite, and oxidizing after fully reacting for 2 hours by ultrasonic oscillation;
(2) Washing the reaction with deionized water for 5 times, and drying the washed natural graphite in a constant temperature drying oven at 60 ℃ for 3 hours to obtain graphite oxide;
(3) Adding ammonium bicarbonate into 10ml of water at a constant temperature of 50 ℃ until the phenomenon of insolubility occurs, and preparing supersaturated ammonium bicarbonate solution;
(4) Placing 3g of dried graphite oxide into 10ml of prepared supersaturated ammonium bicarbonate solution, fully and uniformly mixing, transferring into a closed container with a buffer air bag filled with carbon dioxide as a closed condition, fully and uniformly mixing, performing ultrasonic treatment in ice water bath for 5min, and rapidly transferring into a freezer (-18 ℃) after ultrasonic treatment to fully freeze the graphite oxide;
(5) Placing the frozen mixed material into a vacuum freeze drying box (-60 ℃) until freeze drying is completed, and carrying out simple screening on the dried material to separate the non-intercalated ammonium bicarbonate from the intercalated graphite, and immediately carrying out low-temperature sealing and storage after separation;
(6) Puffing the intercalated graphite at 500 ℃ to prepare the expanded graphite.
Claims (4)
1. A method for preparing expanded graphite by freeze-drying, characterized by comprising the steps of:
(1) Adding an oxidant into natural crystalline flake graphite, fully reacting for 30-180min, oxidizing, fully washing with deionized water for 3-5 times, cleaning the oxidant, and drying at a constant temperature of 35-65 ℃ for 2.5-3.5h;
(2) Adding ammonium bicarbonate into deionized water at constant temperature of 30-50deg.C, stirring until insoluble phenomenon appears, and preparing supersaturated ammonium bicarbonate solution;
(3) Weighing graphite oxide prepared in the step (1), putting the graphite oxide into the supersaturated ammonium bicarbonate solution in the step (2), and controlling the volume ratio of the graphite oxide to the ammonium bicarbonate solution to be 1:2-5, putting the mixture into a closed container filled with carbon dioxide, fully and uniformly mixing, and performing ultrasonic treatment in an ice water bath for 5-60min;
(4) Rapidly transferring the mixture to a freezing box at the temperature of minus 15 to minus 20 ℃ after the ultrasonic treatment is finished, fully freezing the mixture, and placing the frozen mixture into a vacuum freeze-drying box at the temperature of minus 55 to minus 65 ℃ until the freeze-drying is finished;
(5) Placing the dried substance into a sieve, slightly shaking to separate graphite oxide from non-intercalated ammonium bicarbonate, and immediately performing sealing preservation at-18-10 ℃ after separation;
(6) And puffing the intercalated graphite at the temperature of 300-900 ℃ to obtain the expanded graphite.
2. A method of preparing expanded graphite by freeze-drying according to claim 1, wherein: the oxidant is potassium permanganate or hydrogen peroxide.
3. A method of preparing expanded graphite by freeze-drying according to claim 2, wherein: the mass ratio of the graphite to the oxidant potassium permanganate is 1:0.2-1.
4. A method of preparing expanded graphite by freeze-drying according to claim 2, wherein: the mass ratio of the graphite to the oxidant hydrogen peroxide is 1:1-10.
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| CN116477620A (en) * | 2023-03-24 | 2023-07-25 | 中国地质大学（武汉） | High-reversible-capacity sodium ion battery anode material, method for preparing same by utilizing large-scale graphite and application thereof |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103058179A (en) * | 2013-01-21 | 2013-04-24 | 张家港市东大工业技术研究院 | Method for preparing spongy graphene oxide by using freeze-drying method |
| CN104787751A (en) * | 2014-01-16 | 2015-07-22 | 中国科学院宁波材料技术与工程研究所 | Graphene powder and preparation method thereof |
| PL408377A1 (en) * | 2014-05-30 | 2015-12-07 | Instytut Technologii Materiałów Elektronicznych | Method for producing flaky graphene by way of direct exfoliation of graphite |
| CN105731440A (en) * | 2016-02-01 | 2016-07-06 | 成都新柯力化工科技有限公司 | Method for achieving stripping preparation of graphene nanoplatelets by means of phase change material |
| CN105776192A (en) * | 2016-02-26 | 2016-07-20 | 成都新柯力化工科技有限公司 | Method for continuously preparing graphene nanoplatelets by means of grinding stripping |
| CN105967171A (en) * | 2016-05-06 | 2016-09-28 | 成都新柯力化工科技有限公司 | Method for preparing organic graphene through grinding and organic graphene |
| CN106006613A (en) * | 2016-05-24 | 2016-10-12 | 广州市霆宇能源科技有限责任公司 | Method for preparing graphene |
| CN109133040A (en) * | 2018-08-07 | 2019-01-04 | 北京科技大学 | A kind of preparation method of the adjustable graphene aerogel of pore-size |
| CN109264710A (en) * | 2018-12-07 | 2019-01-25 | 四川聚创石墨烯科技有限公司 | A method of promoting graphene oxide quality |
| CN111359582A (en) * | 2020-03-23 | 2020-07-03 | 成都新柯力化工科技有限公司 | Graphene composite aerogel formaldehyde-removing material and preparation method thereof |
| CN111377442A (en) * | 2018-12-28 | 2020-07-07 | 内蒙古元瓷新材料科技有限公司 | Method for preparing sulfur-free expanded graphite by using natural fine flakes |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104386680B (en) * | 2014-11-14 | 2016-05-11 | 上海史墨希新材料科技有限公司 | The method of large stretch of Graphene is prepared in scale |
-
2021
- 2021-09-25 CN CN202111124850.9A patent/CN113816371B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103058179A (en) * | 2013-01-21 | 2013-04-24 | 张家港市东大工业技术研究院 | Method for preparing spongy graphene oxide by using freeze-drying method |
| CN104787751A (en) * | 2014-01-16 | 2015-07-22 | 中国科学院宁波材料技术与工程研究所 | Graphene powder and preparation method thereof |
| PL408377A1 (en) * | 2014-05-30 | 2015-12-07 | Instytut Technologii Materiałów Elektronicznych | Method for producing flaky graphene by way of direct exfoliation of graphite |
| CN105731440A (en) * | 2016-02-01 | 2016-07-06 | 成都新柯力化工科技有限公司 | Method for achieving stripping preparation of graphene nanoplatelets by means of phase change material |
| CN105776192A (en) * | 2016-02-26 | 2016-07-20 | 成都新柯力化工科技有限公司 | Method for continuously preparing graphene nanoplatelets by means of grinding stripping |
| CN105967171A (en) * | 2016-05-06 | 2016-09-28 | 成都新柯力化工科技有限公司 | Method for preparing organic graphene through grinding and organic graphene |
| CN106006613A (en) * | 2016-05-24 | 2016-10-12 | 广州市霆宇能源科技有限责任公司 | Method for preparing graphene |
| CN109133040A (en) * | 2018-08-07 | 2019-01-04 | 北京科技大学 | A kind of preparation method of the adjustable graphene aerogel of pore-size |
| CN109264710A (en) * | 2018-12-07 | 2019-01-25 | 四川聚创石墨烯科技有限公司 | A method of promoting graphene oxide quality |
| CN111377442A (en) * | 2018-12-28 | 2020-07-07 | 内蒙古元瓷新材料科技有限公司 | Method for preparing sulfur-free expanded graphite by using natural fine flakes |
| CN111359582A (en) * | 2020-03-23 | 2020-07-03 | 成都新柯力化工科技有限公司 | Graphene composite aerogel formaldehyde-removing material and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 制备低硫高倍数膨胀石墨优化工艺条件的研究;陈小文 等;炭素技术(06);全文 * |
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