CN108101049B - Production process of high-temperature ablation resistant graphite nano powder - Google Patents
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Abstract
The invention relates to the technical field of graphite, in particular to a production process of high-temperature ablation resistant graphite nano powder. The method specifically comprises the following steps: the preparation method comprises the steps of mixing flake graphite powder and hydrogen peroxide at 0-15 ℃, carrying out acidification treatment, carrying out intercalation reaction at the temperature of more than 30 ℃ by adopting a composite phosphoric acid intercalation agent, wherein the composite phosphoric acid intercalation agent is a composite liquid of phosphoric acid and magnesium oxide, carrying out heating expansion at the temperature of more than 600 ℃ after cleaning and drying, and finally crushing to obtain graphite nano powder.
Description
Technical Field
The invention relates to the technical field of graphite, in particular to a production process of high-temperature ablation resistant graphite nano powder.
Background
Graphite is an important nonmetallic mineral and widely distributed in China. It has the physical and chemical properties of high temperature resistance, oxidation resistance, thermal shock resistance, corrosion resistance, high strength, good toughness, high self-lubricating strength, strong heat conduction and electric conductivity, and the like, and is widely applied to the fields of metallurgy, mechanical manufacturing, electronics, batteries, chemical engineering, light industry, military industry, aerospace, national defense, refractory materials, and the like. The micro powder graphite is mainly applied to the electronic and aviation industries, such as picture tube graphite emulsion and graphite electrodes, oil-based colloidal graphite, lubricating oil additives, batteries, pencils and the like. The nano graphite powder is graphite powder particles which are obtained by crushing graphite by a superfine pulverizer, and the graphite powder particles which pass through a nano-grade screen is the nano graphite powder. The grain diameter of the nano graphite powder reaches the nano level.
At present, various ore grinding devices such as a high-speed mechanical impact mill, a jet mill, a vibration mill, a medium stirring mill, a colloid mill and the like are mainly adopted in the preparation method of the flaky nano graphite powder. However, since the graphite mineral belongs to the flake mineral, the higher the fineness of the superfine grinding, the larger the surface energy of the graphite, the more easily electrostatic adsorption is generated between the flake edges of the irregular mineral, the tendency of mutual agglomeration among fine particles is obviously enhanced, and the surface energy of the mineral is reduced after the surfactant molecules are added, so that the adsorption force among the particles is weakened, and the secondary agglomeration of the fine particles can be prevented. Because graphite has self-lubricating property, the preparation process of the micro powder graphite is long in time and serious in energy consumption, and lattice deformation and graphitization degree are reduced.
Another method for preparing graphite micropowder disclosed at present is to adopt explosive and prepared expanded graphite powder to mix for detonation and utilize the detonation to crack the expandable graphite (patent No. CN 200410020906.6). The method has the advantages of high efficiency, high yield and no reduction of graphitization degree in the aspect of preparing graphite micropowder, but because the method carries out the detonation cracking on high-order GICs, the aim of nano-crystallizing the graphite flake cannot be achieved.
Graphite is a good material for preparing a high-temperature-resistant metallurgical crucible, the heat resistance of the phosphoric acid intercalation expanded graphite is higher than that of a common graphite product, and residual phosphorus in the graphite worms after high-temperature expansion can stabilize the edge carbon atoms of a graphene structure and reduce the ablation of the graphite. The ablation resistance of graphite crucibles affects the lifetime of the crucible, the impurity content of the product and the production cost. The better high-temperature ablation resistant graphite crucible product is important equipment for producing high-end alloy.
Disclosure of Invention
The invention aims to solve the problems and provides a production process of high-temperature ablation resistant graphite nano powder.
In order to achieve the purpose, the invention adopts the following technical scheme:
a production process of high-temperature ablation resistant graphite nano powder specifically comprises the following steps: mixing the flake graphite powder and hydrogen peroxide at 0-15 ℃, then carrying out acidification treatment, carrying out intercalation reaction at the temperature of more than 30 ℃ by adopting a composite phosphoric acid intercalation agent, then carrying out heating expansion at the temperature of more than 600 ℃ after cleaning and drying, and finally crushing to obtain the graphite nano powder.
As a further preferable scheme, the method specifically comprises the following steps:
(1) acidifying graphite: uniformly mixing dried scale graphite powder with carbon content more than 97% with hydrogen peroxide in a reaction kettle at 0-15 ℃, adding concentrated nitric acid for mixing, heating to above 25 ℃ for full oxidation, and finally rotating and deacidifying the slurry obtained by oxidation at high speed, wherein the gravity acceleration is more than 50 g;
(2) intercalation of composite phosphoric acid: adding the acidified graphite wet powder into a composite phosphoric acid intercalation agent, uniformly mixing, wherein the composite phosphoric acid intercalation agent is a mixed solution of magnesium oxide dissolved in phosphoric acid, heating the mixed slurry to above 30 ℃ to perform intercalation reaction, and performing high-speed rotation deacidification after the intercalation reaction is finished, wherein the high-speed rotation is specifically that the gravity acceleration is more than 50 g;
(3) cleaning and drying: adding cleaning solution into the intercalated graphite, uniformly mixing, transferring the obtained mixed slurry into a centrifugal separator, and removing the cleaning solution by high-speed rotation; then, sending the wet powder without the cleaning solution into continuous drying equipment, and drying at 60 ℃ until the water content is lower than 2%;
(4) heating and expanding: heating and expanding the dried graphite powder by adopting a vertical electric furnace or microwave composite heating to obtain graphite worms; the furnace temperature is more than 600 ℃;
(5) crushing: and (3) crushing the graphite worms into graphite flakes with high length-diameter ratio and nanometer thickness by using a high-speed jet mill.
Magnesium oxide is a common refractory material, a magnesia carbon brick with a small amount of added graphite is a main lining of a blast furnace, and the carbon content of a steel product can be effectively reduced and the quality of a steel product can be improved by replacing graphite powder with graphene or high-length-diameter-ratio nano graphite flakes.
As a further preferable scheme, the step (1) of acidifying graphite specifically comprises the following steps:
a) 1 part of crystalline flake graphite powder which is dried at 60 ℃ and has the carbon content of more than 97 percent is put into an enamel jacket reaction kettle with heating and cooling functions and is cooled to 0-15 ℃, wherein the flake diameter range of the crystalline flake graphite powder is + # 250-30;
b) then adding 0.05-0.5 part of hydrogen peroxide with the same low temperature of 5-15 ℃ and uniformly mixing; the concentration of hydrogen peroxide is more than 30 percent;
c) then adding 0.5-5 parts of concentrated nitric acid with the same low temperature of 5-15 ℃ for uniformly mixing, raising the temperature to 25-45 ℃ after mixing for 30 minutes, and keeping the temperature for 5-200 minutes;
d) and then rotating and deacidifying the obtained slurry at a high speed to obtain the acidified graphite.
As a further preferable scheme, the intercalation of the composite phosphoric acid in the step (2) specifically comprises the following steps: adding 0.25-5 parts of composite phosphoric acid intercalation agent into the acidified graphite wet powder, uniformly mixing, heating to 30-80 ℃, keeping for 30-300 minutes, and cooling to room temperature; and finally, deacidifying by adopting high-speed rotation.
As a further preferable scheme, the composite phosphoric acid intercalation agent in the step (3) is prepared by dissolving magnesium oxide powder in 85% phosphoric acid, wherein the weight ratio content of magnesium oxide is 0.1% -10%.
As a further preferable scheme, in the step (3), before the cleaning solution is removed by high-speed rotation, 2-10 parts of the cleaning solution is added into the intercalated graphite, and the mixture is uniformly mixed.
As a further preferable scheme, the cleaning and drying in the step (3) are carried out, and the formula of the cleaning solution comprises the following components in parts by weight: 1 part of deionized water and 0.01-0.6 part of ethanol.
As a further preferred option, the heating of step (4) expands, the specific expansion of the graphite worms being greater than 100 ml/g.
As a further preferable scheme, in the step (5), the length-diameter ratio of the graphite flakes is more than 100.
As a further preferred scheme, the production process of the high-temperature ablation-resistant graphite nano powder specifically comprises the following steps:
(1) acidifying graphite: drying the flake graphite powder at 60 ℃ to ensure that the water content is lower than 2%, then adding 1 part of the flake graphite powder into a reaction kettle, cooling to 0-15 ℃, then adding 0.1-0.3 part of hydrogen peroxide with the concentration of 0-15 ℃ being more than 30%, uniformly mixing, then adding 1.1-2.8 parts of concentrated nitric acid with the concentration of 0-15 ℃ being more than 65%, uniformly mixing, raising to 25-45 ℃ after mixing for 30 minutes, keeping for 5-200 minutes, fully oxidizing, and finally rotating and deacidifying the slurry obtained by oxidation at a high speed, wherein the gravity acceleration is more than 50 g; wherein the flake graphite powder has a flake diameter range of + #250 to- # 30;
(2) intercalation of composite phosphoric acid: adding 0.8-3 parts of composite phosphoric acid intercalation agent into the acidified graphite wet powder, uniformly mixing, heating to 30-80 ℃, keeping for 30-300 minutes, and cooling to room temperature; finally, deacidifying by adopting high-speed rotation; the composite phosphoric acid intercalation agent is prepared by dissolving magnesium oxide powder in 85 percent phosphoric acid, wherein the weight ratio content of magnesium oxide is 2-5 percent; performing high-speed rotation deacidification after the intercalation reaction is finished, wherein the high-speed rotation is specifically that the gravity acceleration is more than 50 g;
(3) cleaning and drying: adding 4-6 parts of cleaning fluid into the intercalated graphite, uniformly mixing, transferring the obtained mixed slurry into a centrifugal separator, and removing the cleaning fluid by high-speed rotation; then, sending the wet powder without the cleaning solution into continuous drying equipment, and drying at 60 ℃ until the water content is lower than 2%; the cleaning solution specifically comprises: mixing 1 part of deionized water and 0.1-0.3 part of ethanol to obtain a mixed solution;
(4) heating and expanding: heating and expanding the dried graphite powder by adopting a vertical electric furnace or microwave composite heating to obtain graphite worms; wherein the furnace temperature is more than 600 ℃, and the specific expansion of the graphite worms is more than 200 ml/g;
(5) crushing: crushing the graphite worms into graphite flakes with high length-diameter ratio and nanometer thickness by using a high-speed jet mill, namely obtaining graphite nanometer powder; the length-diameter ratio of the graphite flakes is greater than 500.
Compared with the prior art, the invention has the beneficial effects that: the carbon atoms on the active edge of the graphite nano-scale are stabilized due to the synergistic effect of the phosphoric acid and the magnesium oxide, so that the high-temperature oxidation resistance of the graphite is improved.
Detailed Description
The technical solution of the present invention is further described below by means of specific examples.
The raw materials used in the examples of the present invention are those commonly used in the art, and the methods used in the examples are those conventional in the art, unless otherwise specified.
A production process of high-temperature ablation resistant graphite nano powder comprises the following preliminary implementation steps: mixing the flake graphite powder and hydrogen peroxide at 0-15 ℃, then carrying out acidification treatment, carrying out intercalation reaction at the temperature of more than 30 ℃ by adopting a composite phosphoric acid intercalation agent, then carrying out heating expansion at the temperature of more than 600 ℃ after cleaning and drying, and finally crushing to obtain the graphite nano powder.
The overall synthesis procedure is as follows:
(1) acidifying graphite: uniformly mixing dried scale graphite powder with carbon content more than 97% with hydrogen peroxide in a reaction kettle at 0-15 ℃, adding concentrated nitric acid for mixing, heating to above 25 ℃ for full oxidation, and finally rotating and deacidifying the slurry obtained by oxidation at high speed, wherein the gravity acceleration is more than 50 g;
specifically, the acidification of graphite specifically comprises the following steps:
a) 1 part of crystalline flake graphite powder which is dried at 60 ℃ and has the carbon content of more than 97 percent is put into an enamel jacket reaction kettle with heating and cooling functions and is cooled to 0-15 ℃, wherein the flake diameter range of the crystalline flake graphite powder is + # 250-30;
b) then adding 0.05-0.5 part of hydrogen peroxide with the same low temperature of 5-15 ℃ and uniformly mixing; the concentration of hydrogen peroxide is more than 30 percent;
c) then adding 0.5-5 parts of concentrated nitric acid with the same low temperature of 5-15 ℃ for uniformly mixing, raising the temperature to 25-45 ℃ after mixing for 30 minutes, and keeping the temperature for 5-200 minutes;
d) and then rotating and deacidifying the obtained slurry at a high speed to obtain the acidified graphite.
(2) Intercalation of composite phosphoric acid: adding the acidified graphite wet powder into a composite phosphoric acid intercalation agent, uniformly mixing, wherein the composite phosphoric acid intercalation agent is a mixed solution of magnesium oxide dissolved in phosphoric acid, heating the mixed slurry to above 30 ℃ to perform intercalation reaction, and performing high-speed rotation deacidification after the intercalation reaction is finished, wherein the high-speed rotation is specifically that the gravity acceleration is more than 50 g;
specifically, the composite phosphoric acid intercalation specifically comprises the following steps: adding 0.25-5 parts of composite phosphoric acid intercalation agent into the acidified graphite wet powder, uniformly mixing, heating to 30-80 ℃, keeping for 30-300 minutes, and cooling to room temperature; and finally, deacidifying by adopting high-speed rotation.
(3) Cleaning and drying: adding cleaning solution into the intercalated graphite, uniformly mixing, transferring the obtained mixed slurry into a centrifugal separator, and removing the cleaning solution by high-speed rotation; then, sending the wet powder without the cleaning solution into continuous drying equipment, and drying at 60 ℃ until the water content is lower than 2%; the composite phosphoric acid intercalation agent is prepared by dissolving magnesium oxide powder in 85% phosphoric acid, wherein the weight ratio content of magnesium oxide is 0.1% -10%. Before the cleaning solution is removed by high-speed rotation, 2-10 parts of cleaning solution is added into the intercalated graphite and mixed evenly. The formula of the cleaning solution comprises the following components in parts by weight: 1 part of deionized water and 0.01-0.6 part of ethanol.
(4) Heating and expanding: heating and expanding the dried graphite powder by adopting a vertical electric furnace or microwave composite heating to obtain graphite worms; the furnace temperature is more than 600 ℃; the specific expansion of the graphite worms was greater than 100 ml/g.
(5) Crushing: and (3) crushing the graphite worms into graphite flakes with high length-diameter ratio and nanometer thickness by using a high-speed jet mill, wherein the length-diameter ratio of the crushed graphite flakes is more than 100.
Example 1:
a production process of high-temperature ablation resistant graphite nano powder specifically comprises the following steps:
(1) acidifying graphite: drying the flake graphite powder at 60 ℃ to enable the water content of the flake graphite powder to be lower than 2%, then adding 1 part (1 part being 1kg) of the flake graphite powder into a reaction kettle, cooling to 5 ℃, then adding 0.1 part (1 part being 1kg) of hydrogen peroxide with the concentration of 5 ℃ being more than 30% (40%), uniformly mixing, then adding 2.8 parts (1 part being 1kg) of concentrated nitric acid with the concentration of 5 ℃ being more than 65% (70%), uniformly mixing, raising the temperature to 25-30 ℃ after mixing for 30 minutes, keeping for 10 minutes, fully oxidizing, and finally carrying out high-speed rotation deacidification on the slurry obtained by oxidation, wherein the high-speed rotation is specifically that the gravity acceleration is more than 50 g; wherein the flake graphite powder has a flake diameter range of + #250 to- # 30;
(2) intercalation of composite phosphoric acid: adding 0.8 part (1 part is 1kg) of composite phosphoric acid intercalation agent into the acidified graphite wet powder, uniformly mixing, heating to 30-50 ℃, keeping for 30-60 minutes, and cooling to room temperature; finally, deacidifying by adopting high-speed rotation; the composite phosphoric acid intercalation agent is prepared by dissolving magnesium oxide powder in 85 percent (90 percent) phosphoric acid, wherein the weight ratio of magnesium oxide is 5 percent; performing high-speed rotation deacidification after the intercalation reaction is finished, wherein the high-speed rotation is specifically that the gravity acceleration is more than 50 g;
(3) cleaning and drying: adding 4 parts of cleaning solution (1 part is 1kg) into the intercalated graphite, uniformly mixing, transferring the obtained mixed slurry into a centrifugal separator, and removing the cleaning solution by high-speed rotation; then, sending the wet powder without the cleaning solution into continuous drying equipment, and drying at 60 ℃ until the water content is lower than 2%; the cleaning solution specifically comprises: 1 part (1 kg) of deionized water and 0.3 part (1 kg) of ethanol are mixed to obtain a mixed solution, wherein the ratio of the deionized water to the ethanol is 10: 3;
(4) heating and expanding: heating and expanding the dried graphite powder by adopting a vertical electric furnace or microwave composite heating to obtain graphite worms; wherein the furnace temperature is more than 600 ℃, and the specific expansion of the graphite worms is more than 200 ml/g;
(5) crushing: crushing the graphite worms into graphite flakes with high length-diameter ratio and nanometer thickness by using a high-speed jet mill, namely obtaining graphite nanometer powder; the length-diameter ratio of the graphite flakes is greater than 500.
Example 2:
a production process of high-temperature ablation resistant graphite nano powder specifically comprises the following steps:
(1) acidifying graphite: drying crystalline flake graphite powder at 60 ℃ to enable the water content of the crystalline flake graphite powder to be lower than 2%, adding 1 part (1 part being 2kg) of crystalline flake graphite powder into a reaction kettle, cooling to 10 ℃, adding 0.3 part (1 part being 2kg) of hydrogen peroxide with the concentration of 10 ℃ being more than 30%, mixing uniformly, adding 1.1 part (1 part being 2kg) of concentrated nitric acid with the concentration of 10 ℃ being more than 65% (68%), mixing uniformly, raising the temperature to 25-45 ℃ after mixing for 30 minutes, keeping the temperature for 100 minutes, fully oxidizing, and finally rotating and deacidifying the slurry obtained by oxidation at a high speed, wherein the gravity acceleration is more than 50 g; wherein the flake graphite powder has a flake diameter range of + #250 to- # 30;
(2) intercalation of composite phosphoric acid: adding 3 parts (1 part is 2kg) of composite phosphoric acid intercalation agent into the acidified graphite wet powder, uniformly mixing, heating to 60-80 ℃, keeping for 150 minutes, and cooling to room temperature; finally, deacidifying by adopting high-speed rotation; the composite phosphoric acid intercalation agent is prepared by dissolving magnesium oxide powder in 85 percent (88 percent) of phosphoric acid, wherein the weight ratio content of magnesium oxide is 2 percent; performing high-speed rotation deacidification after the intercalation reaction is finished, wherein the high-speed rotation is specifically that the gravity acceleration is more than 50 g;
(3) cleaning and drying: adding 6 parts (1 part is 2kg) of cleaning solution into the intercalated graphite, uniformly mixing, transferring the obtained mixed slurry into a centrifugal separator, and removing the cleaning solution by high-speed rotation; then, sending the wet powder without the cleaning solution into continuous drying equipment, and drying at 60 ℃ until the water content is lower than 2%; the cleaning solution specifically comprises: mixing 1 part (1 part is 2kg) of deionized water and 0.1 part of ethanol to obtain a mixed solution, wherein the ratio of the deionized water to the ethanol is 10: 1;
(4) heating and expanding: heating and expanding the dried graphite powder by adopting a vertical electric furnace or microwave composite heating to obtain graphite worms; wherein the furnace temperature is more than 600 ℃, and the specific expansion of the graphite worms is more than 200 ml/g;
(5) crushing: crushing the graphite worms into graphite flakes with high length-diameter ratio and nanometer thickness by using a high-speed jet mill, namely obtaining graphite nanometer powder; the length-diameter ratio of the graphite flakes is greater than 500.
Claims (8)
1. A production process of high-temperature ablation resistant graphite nano powder is characterized by comprising the following steps: mixing flake graphite powder and hydrogen peroxide at 0-15 ℃, then carrying out acidification treatment, carrying out intercalation reaction at the temperature of more than 30 ℃ by adopting a composite phosphoric acid intercalation agent, then carrying out heating expansion at the temperature of more than 600 ℃ after cleaning and drying, and finally crushing to obtain graphite nano powder;
the method specifically comprises the following steps:
(1) acidifying graphite: uniformly mixing dried scale graphite powder with carbon content more than 97% with hydrogen peroxide in a reaction kettle at 0-15 ℃, adding concentrated nitric acid for mixing, heating to above 25 ℃ for full oxidation, and finally rotating and deacidifying the slurry obtained by oxidation at high speed, wherein the gravity acceleration is more than 50 g;
(2) intercalation of composite phosphoric acid: adding the acidified graphite wet powder into a composite phosphoric acid intercalation agent, uniformly mixing, wherein the composite phosphoric acid intercalation agent is a mixed solution of magnesium oxide dissolved in phosphoric acid, heating the mixed slurry to above 30 ℃ to perform intercalation reaction, and performing high-speed rotation deacidification after the intercalation reaction is finished, wherein the high-speed rotation is specifically that the gravity acceleration is more than 50 g; the composite phosphoric acid intercalation agent is prepared by dissolving magnesium oxide powder in 85 percent phosphoric acid, wherein the weight ratio content of magnesium oxide is 0.1 to 10 percent;
(3) cleaning and drying: adding cleaning solution into the intercalated graphite, uniformly mixing, transferring the obtained mixed slurry into a centrifugal separator, and removing the cleaning solution by high-speed rotation; then, sending the wet powder without the cleaning solution into continuous drying equipment, and drying at 60 ℃ until the water content is lower than 2%;
(4) heating and expanding: heating and expanding the dried graphite powder by adopting a vertical electric furnace or microwave composite heating to obtain graphite worms; the furnace temperature is more than 600 ℃;
(5) crushing: and (3) crushing the graphite worms into graphite flakes with high length-diameter ratio and nanometer thickness by using a high-speed jet mill.
2. The process for producing high temperature ablation resistant graphite nano-powder as claimed in claim 1, wherein the step (1) of acidifying graphite specifically comprises the steps of:
a) 1 part of crystalline flake graphite powder which is dried at 60 ℃ and has the carbon content of more than 97 percent is put into an enamel jacket reaction kettle with heating and cooling functions and is cooled to 0-15 ℃, wherein the flake diameter range of the crystalline flake graphite powder is + # 250-30;
b) then adding 0.05-0.5 part of hydrogen peroxide with the same low temperature of 5-15 ℃ and uniformly mixing; the concentration of hydrogen peroxide is more than 30 percent;
c) then adding 0.5-5 parts of concentrated nitric acid with the same low temperature of 5-15 ℃ for uniformly mixing, raising the temperature to 25-45 ℃ after mixing for 30 minutes, and keeping the temperature for 5-200 minutes;
d) and then rotating and deacidifying the obtained slurry at a high speed to obtain the acidified graphite.
3. The process for producing high-temperature ablation resistant graphite nano powder as claimed in claim 1, wherein the intercalation of the composite phosphoric acid in the step (2) specifically comprises the following steps: adding 0.25-5 parts of composite phosphoric acid intercalation agent into the acidified graphite wet powder, uniformly mixing, heating to 30-80 ℃, keeping for 30-300 minutes, and cooling to room temperature; and finally, deacidifying by adopting high-speed rotation.
4. The process for producing high-temperature ablation resistant graphite nano powder as claimed in claim 1, wherein in the step (3), 2-10 parts of cleaning solution is added into the intercalated graphite before the cleaning solution is removed by high-speed rotation, and the mixture is uniformly mixed.
5. The process for producing high-temperature ablation resistant graphite nano powder as claimed in claim 1, wherein the step (3) of cleaning and drying comprises the following components in parts by weight: 1 part of deionized water and 0.01-0.6 part of ethanol.
6. The process for producing high temperature ablation resistant graphite nano powder as claimed in claim 1, wherein the heating expansion of the step (4) is larger than 100ml/g of the specific expansion of the graphite worms.
7. The process for producing high temperature ablation resistant graphite nano powder as claimed in claim 1, wherein the pulverization of the step (5) has an aspect ratio of graphite flakes greater than 100.
8. The process for producing high-temperature ablation resistant graphite nano-powder as claimed in any one of claims 1 to 7, which comprises the following steps:
(1) acidifying graphite: drying the flake graphite powder at 60 ℃ to ensure that the water content is lower than 2%, then adding 1 part of the flake graphite powder into a reaction kettle, cooling to 0-15 ℃, then adding 0.1-0.3 part of hydrogen peroxide with the concentration of 0-15 ℃ being more than 30%, uniformly mixing, then adding 1.1-2.8 parts of concentrated nitric acid with the concentration of 0-15 ℃ being more than 65%, uniformly mixing, raising to 25-45 ℃ after mixing for 30 minutes, keeping for 5-200 minutes, fully oxidizing, and finally rotating and deacidifying the slurry obtained by oxidation at a high speed, wherein the gravity acceleration is more than 50 g; wherein the flake graphite powder has a flake diameter range of + #250 to- # 30;
(2) intercalation of composite phosphoric acid: adding 0.8-3 parts of composite phosphoric acid intercalation agent into the acidified graphite wet powder, uniformly mixing, heating to 30-80 ℃, keeping for 30-300 minutes, and cooling to room temperature; finally, deacidifying by adopting high-speed rotation; the composite phosphoric acid intercalation agent is prepared by dissolving magnesium oxide powder in 85 percent phosphoric acid, wherein the weight ratio content of magnesium oxide is 2-5 percent; performing high-speed rotation deacidification after the intercalation reaction is finished, wherein the high-speed rotation is specifically that the gravity acceleration is more than 50 g;
(3) cleaning and drying: adding 4-6 parts of cleaning fluid into the intercalated graphite, uniformly mixing, transferring the obtained mixed slurry into a centrifugal separator, and removing the cleaning fluid by high-speed rotation; then, sending the wet powder without the cleaning solution into continuous drying equipment, and drying at 60 ℃ until the water content is lower than 2%; the cleaning solution specifically comprises: mixing 1 part of deionized water and 0.1-0.3 part of ethanol to obtain a mixed solution;
(4) heating and expanding: heating and expanding the dried graphite powder by adopting a vertical electric furnace or microwave composite heating to obtain graphite worms; wherein the furnace temperature is more than 600 ℃, and the specific expansion of the graphite worms is more than 200 ml/g;
(5) crushing: crushing the graphite worms into graphite flakes with high length-diameter ratio and nanometer thickness by using a high-speed jet mill, namely obtaining graphite nanometer powder; the length-diameter ratio of the graphite flakes is greater than 500.
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| CN1431726A (en) * | 2003-01-10 | 2003-07-23 | 青岛建筑工程学院 | Method for preparing expansible graphite ting powder |
| US20110178296A1 (en) * | 2008-09-30 | 2011-07-21 | Sambhu Prasad Sarma Mallela | Process for preparing pyrimidine propenaldehyde |
| CN105271170A (en) * | 2015-11-03 | 2016-01-27 | 山西中兴环能科技有限公司 | Preparation method of nano carbon and composite material of nano carbon |
| CN105883780A (en) * | 2015-12-15 | 2016-08-24 | 中南大学 | Method for preparing high-purity flake graphite |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1431726A (en) * | 2003-01-10 | 2003-07-23 | 青岛建筑工程学院 | Method for preparing expansible graphite ting powder |
| US20110178296A1 (en) * | 2008-09-30 | 2011-07-21 | Sambhu Prasad Sarma Mallela | Process for preparing pyrimidine propenaldehyde |
| CN105271170A (en) * | 2015-11-03 | 2016-01-27 | 山西中兴环能科技有限公司 | Preparation method of nano carbon and composite material of nano carbon |
| CN105883780A (en) * | 2015-12-15 | 2016-08-24 | 中南大学 | Method for preparing high-purity flake graphite |
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