CN110745818A - Preparation method of high-purity graphite - Google Patents
Preparation method of high-purity graphite Download PDFInfo
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- CN110745818A CN110745818A CN201810830228.1A CN201810830228A CN110745818A CN 110745818 A CN110745818 A CN 110745818A CN 201810830228 A CN201810830228 A CN 201810830228A CN 110745818 A CN110745818 A CN 110745818A
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Abstract
The invention discloses a preparation method of high-purity graphite. The invention aims to solve the problems of environmental pollution, complex process and higher cost in the existing graphite purification method. The method comprises the following steps: firstly, mixing a purification medium and graphite, putting the mixture into a closed pressure container, and reacting for 30-90 min by adopting an external heating mode to ensure that the temperature of the mixture of the purification medium and the graphite reaches 50-180 ℃, and keeping the pressure at 1-10 atmospheric pressures; and secondly, after the reaction is finished, releasing pressure, centrifuging the mixture through a high-speed centrifuge, separating the medium from graphite, and cleaning the graphite through pure water until the pH value is more than 6 to obtain the high-purity graphite. The method has the advantages of less environmental pollution, simple process, recyclable medium, greatly reduced cost and high purity of purified graphite. The method is used for purifying the graphite.
Description
Technical Field
The invention relates to a purification method of graphite, in particular to a preparation method of high-purity graphite.
Background
Because graphite has the characteristics of good electric conduction, heat conduction, high temperature resistance, self lubrication and the like, the graphite becomes one of necessary raw materials for certain special industries, for example, the high temperature resistance of graphite is utilized, and a high-purity graphite block is adopted to prepare the nose cone of a rocket; the high heat conduction characteristic of graphite is utilized, and the high-purity graphite film is adopted to prepare a heat radiator of an electronic device and the like. However, the purity of the graphite raw material prepared by the current graphite beneficiation technology is only 98% at most, and the application field of the graphite raw material can be expanded only by further purification, so that the graphite raw material can show the irreplaceable position.
The method is characterized in that the principle that fluoric acid (HF) or salt (NH3F, NaF and the like) can corrode minerals such as silicon, aluminum, iron and the like is utilized in China at the earliest time, the fluoric medium is developed on a large scale for graphite purification, although the purification technology is simple, the pollution is large, and the method is forbidden at present; graphite high-temperature purification, namely preparing a series of high-temperature furnaces and creatively developing a plurality of technical methods for continuous high-temperature purification of graphite by utilizing the principle that graphite is resistant to high temperature and most of associated minerals of graphite are gasified at the temperature of more than 2500 ℃, but all equipment in China at present has the defects of high energy consumption and low efficiency, and domestic graphite enterprises only carry out small-scale or tentative production; the alkali-acid method purification is a method for removing most of graphite associated minerals by using molten sodium hydroxide and removing metal impurities such as iron by using hydrochloric acid, the cost is greatly reduced compared with high-temperature purification, and the pollution is reduced compared with HF purification, but the process is more complicated, the waste alkali liquor is not easy to recycle, and the cost needs to be further reduced. At present, the graphite industry needs to invent a new graphite purification technology with high efficiency, low cost and controllable environmental pollution.
Disclosure of Invention
The invention aims to solve the problems of environmental pollution, complex process and higher cost of the existing graphite purification method, and provides a preparation method of high-purity graphite.
The preparation method of the high-purity graphite comprises the following steps:
the purification medium comprises acid, sodium acetate and sodium citrate, wherein the acid is a mixture of one or more of phosphoric acid with the mass percent of 70-85%, sulfuric acid with the mass percent of 65-93% and acetic acid with the mass percent of 50-70% according to any ratio, the mass of the sodium acetate is 2-10% of the total mass of the acid, and the mass of the sodium citrate is 1-8% of the total mass of the acid;
mixing the purification medium and graphite, putting the mixture into a closed pressure container, and reacting for 30-90 min by adopting an external heating mode to enable the temperature of the mixture of the purification medium and the graphite to reach 50-180 ℃, and keeping the pressure at 1-10 atmospheric pressures;
and thirdly, after the reaction is finished, releasing pressure, centrifuging the mixture through a high-speed centrifuge, separating the medium from graphite, and cleaning the graphite through pure water until the pH value is more than 6 to obtain the high-purity graphite.
The separated purification medium can be recycled.
The diluted acid solution after cleaning is used as cleaning water again after being subjected to seed treatment, precipitation and filtration, and one or more of calcium phosphate, calcium sulfate, calcium acetate and the like after precipitation can be used as filling raw materials of other composite materials.
The invention has the beneficial effects that:
1. impurities contained in the graphite are removed by a liquid phase method, the graphite impurities are removed without fluoric acid or salt, and compared with a pure fluorine-containing medium, the purification is realized, so that the environmental pollution is less;
2. the purification of the contrast alkali-acid has no alkali fusion process, the process is simple, the medium can be recycled, and the cost can be greatly reduced.
3. The graphite purified by the method has higher purity, and the carbon content is more than 99.9 percent and is 99.9 to 99.96 percent.
Detailed Description
The technical solution of the present invention is not limited to the following specific embodiments, but includes any combination of the specific embodiments.
The first embodiment is as follows: the preparation method of the high-purity graphite of the embodiment comprises the following steps:
the purification medium comprises acid, sodium acetate and sodium citrate, wherein the acid is a mixture of one or more of phosphoric acid with the mass percent of 70-85%, sulfuric acid with the mass percent of 65-93% and acetic acid with the mass percent of 50-70% according to any ratio, the mass of the sodium acetate is 2-10% of the total mass of the acid, and the mass of the sodium citrate is 1-8% of the total mass of the acid;
mixing the purification medium and graphite, putting the mixture into a closed pressure container, and reacting for 30-90 min by adopting an external heating mode to enable the temperature of the mixture of the purification medium and the graphite to reach 50-180 ℃, and keeping the pressure at 1-10 atmospheric pressures;
and thirdly, after the reaction is finished, releasing pressure, centrifuging the mixture through a high-speed centrifuge, separating the medium from graphite, and cleaning the graphite through pure water until the pH value is more than 6 to obtain the high-purity graphite.
The second embodiment is as follows: the first difference between the present embodiment and the specific embodiment is: in the first step, the acid is a mixture consisting of one or more of 75-80% by mass of phosphoric acid, 70-90% by mass of sulfuric acid and 55-65% by mass of acetic acid according to any ratio. The rest is the same as the first embodiment.
The third concrete implementation mode: the first difference between the present embodiment and the specific embodiment is: in the first step, the acid is one or a mixture of more of phosphoric acid with the mass percent of 78%, sulfuric acid with the mass percent of 80% and acetic acid with the mass percent of 60% according to any ratio. The rest is the same as the first embodiment.
The fourth concrete implementation mode: the first difference between the present embodiment and the specific embodiment is: in the second step, the weight ratio of the purification medium to the graphite is (5-1.5): 1. The rest is the same as the first embodiment.
The fifth concrete implementation mode: the first difference between the present embodiment and the specific embodiment is: and in the second step, the temperature of the mixture of the purification medium and the graphite reaches 80-150 ℃. The rest is the same as the first embodiment.
The sixth specific implementation mode: the first difference between the present embodiment and the specific embodiment is: and in the second step, the temperature of the mixture of the purification medium and the graphite reaches 100-120 ℃. The rest is the same as the first embodiment.
The seventh embodiment: the first difference between the present embodiment and the specific embodiment is: and in the second step, the volume of the mixture of the purification medium and the graphite accounts for 70-90% of the volume of the closed pressure container. The rest is the same as the first embodiment.
The specific implementation mode is eight: the first difference between the present embodiment and the specific embodiment is: the rotation speed of the centrifuge in the third step is at least 1200 r/min. The rest is the same as the first embodiment.
To verify the beneficial effects of the present invention, the following experiments were performed:
example 1:
the preparation method of the high-purity graphite of the embodiment comprises the following steps:
firstly, the purification medium consists of 100g of phosphoric acid with the mass percentage concentration of 78%, 20g of sulfuric acid with the mass percentage concentration of 80%, 10g of acetic acid with the mass percentage concentration of 60%, 6g of sodium acetate and 3g of sodium citrate;
mixing a purification medium and 80g of graphite, putting the mixture into a closed pressure container, wherein the volume of the mixture of the purification medium and the graphite accounts for 90% of the volume of the closed pressure container, adopting an external heating mode to enable the temperature of the mixture of the purification medium and the graphite to reach 100 ℃, keeping the pressure at 8 atmospheric pressures, and reacting for 90 min;
and thirdly, after the reaction is finished, releasing pressure, centrifuging the mixture through a high-speed centrifuge at the rotating speed of 1200 rpm, separating the medium from graphite, and cleaning the graphite through pure water until the pH value is more than 6 to obtain the high-purity graphite.
The carbon content of the high purity graphite prepared in this example was 99.9%.
Example 2:
the preparation method of the high-purity graphite of the embodiment comprises the following steps:
firstly, the purification medium consists of 50g of phosphoric acid with the mass percentage concentration of 78%, 50g of sulfuric acid with the mass percentage concentration of 80%, 30g of acetic acid with the mass percentage concentration of 60%, 6g of sodium acetate and 3g of sodium citrate;
mixing a purification medium and 80g of graphite, putting the mixture into a closed pressure container, wherein the volume of the mixture of the purification medium and the graphite accounts for 80% of the volume of the closed pressure container, adopting an external heating mode to enable the temperature of the mixture of the purification medium and the graphite to reach 150 ℃, keeping the pressure at 10 atmospheric pressures, and reacting for 90 min;
and thirdly, after the reaction is finished, releasing pressure, centrifuging the mixture through a high-speed centrifuge at the rotating speed of 1200 rpm, separating the medium from graphite, and cleaning the graphite through pure water until the pH value is more than 6 to obtain the high-purity graphite.
The carbon content of the high purity graphite prepared in this example was 99.93%.
Example 3:
the preparation method of the high-purity graphite of the embodiment comprises the following steps:
firstly, a purification medium consists of 100g of phosphoric acid with the mass percentage concentration of 78%, 20g of sulfuric acid with the mass percentage concentration of 80%, 10g of acetic acid with the mass percentage concentration of 60%, 6g of sodium acetate and 3g of sodium citrate;
mixing a purification medium and 80g of graphite, putting the mixture into a closed pressure container, wherein the volume of the mixture of the purification medium and the graphite accounts for 80% of the volume of the closed pressure container, adopting an external heating mode to enable the temperature of the mixture of the purification medium and the graphite to reach 150 ℃, keeping the pressure at 10 atmospheric pressures, and reacting for 90 min;
and thirdly, after the reaction is finished, releasing pressure, centrifuging the mixture through a high-speed centrifuge at the rotating speed of 1200 rpm, separating the medium from graphite, and cleaning the graphite through pure water until the pH value is more than 6 to obtain the high-purity graphite.
Fourthly, the carbon content of the high-purity graphite prepared in the embodiment is 99.95%.
Claims (5)
1. The preparation method of the high-purity graphite is characterized by comprising the following steps of:
the purification medium comprises acid, sodium acetate and sodium citrate, wherein the acid is a mixture of one or more of phosphoric acid with the mass percent of 70-85%, sulfuric acid with the mass percent of 65-93% and acetic acid with the mass percent of 50-70% according to any ratio, the mass of the sodium acetate is 2-10% of the total mass of the acid, and the mass of the sodium citrate is 1-8% of the total mass of the acid;
mixing the purification medium and graphite, putting the mixture into a closed pressure container, and reacting for 30-90 min by adopting an external heating mode to ensure that the temperature of the mixture of the purification medium and the graphite reaches 100-150 ℃ and the pressure is kept at 8-10 atmospheric pressures;
after the reaction is finished, releasing pressure, centrifuging the mixture through a high-speed centrifuge, separating a medium from graphite, and cleaning the graphite through pure water until the pH value is more than 6 to obtain high-purity graphite; in the second step, the weight ratio of the purification medium to the graphite is (5-1.5): 1.
2. The method for preparing high-purity graphite according to claim 1, wherein: in the first step, the acid is a mixture consisting of one or more of 75-80% by mass of phosphoric acid, 70-90% by mass of sulfuric acid and 55-65% by mass of acetic acid according to any ratio.
3. The method for preparing high-purity graphite according to claim 1, wherein: in the first step, the acid is one or a mixture of more of phosphoric acid with the mass percent of 78%, sulfuric acid with the mass percent of 80% and acetic acid with the mass percent of 60% according to any ratio.
4. The method for preparing high-purity graphite according to claim 1, wherein: and in the second step, the volume of the mixture of the purification medium and the graphite accounts for 70-90% of the volume of the closed pressure container.
5. The method for preparing high-purity graphite according to claim 1, wherein: the rotation speed of the centrifuge in the third step is at least 1200 r/min.
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| CN201810830228.1A CN110745818A (en) | 2018-07-24 | 2018-07-24 | Preparation method of high-purity graphite |
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| CN201810830228.1A CN110745818A (en) | 2018-07-24 | 2018-07-24 | Preparation method of high-purity graphite |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114702032A (en) * | 2022-04-16 | 2022-07-05 | 凯盛石墨碳材料有限公司 | Preparation method of lithium ion battery cathode material |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114702032A (en) * | 2022-04-16 | 2022-07-05 | 凯盛石墨碳材料有限公司 | Preparation method of lithium ion battery cathode material |
| CN114702032B (en) * | 2022-04-16 | 2023-09-08 | 凯盛石墨碳材料有限公司 | Preparation method of lithium ion battery anode material |
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