Low-temperature preparation method and preparation device of graphite fluoride

Abstract

The invention relates to the technical field of fine chemical engineering, and discloses a low-temperature preparation method and preparation device of graphite fluoride, and the preparation method comprises the following steps: adding a graphite raw material into a high-pressure reaction kettle, and evacuating and replacing the high-pressure reaction kettle and a pipeline system; slowly adding liquid raw materials ClF3 and HF at the speed of 8-10kg / h, and setting the temperature in the high-pressure reaction kettle to be-10 to-20 DEG C; the method comprises the following steps: pretreating a graphite raw material in a nitrogen atmosphere; after the pretreatment is completed, reducing the temperature in the high-pressure reaction kettle to-10 to-20 DEG C, and adjusting the pressure; slowly raising the temperature in the high-pressure reaction kettle to 150-200 DEG C at the rate of about 5 DEG C / min, and reacting for 3-4 hours to obtain the carbon monofluoride. The mixed liquid of ClF3 and HF is adopted to etch the graphite raw material, in the liquid state, HF can effectively increase the dissociation degree of ClF3, accelerate the reaction rate of ClF3 and better etch the graphite raw material, and the reaction temperature is 150-200 DEG C. Compared with numerous patents and methods for producing graphite fluoride, the method has the advantages that the reaction temperature is effectively reduced, and the intrinsic safety degree is improved.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical industry, and in particular to a low-temperature preparation method and a preparation device of fluorinated graphite. Background Art

[0002] Graphite fluoride is a new type of carbon / graphite material with high technology, high performance and high efficiency in the world today. Graphite fluoride has good thermal stability, maintains the original layered structure of graphite, and because fluorine atoms enter the graphite interlayers and form covalent bonds with the π electrons between the graphite interlayers, the bond energy between the graphite interlayers is significantly reduced to only 8.4 kJ·mol -1 , much higher than the interlayer energy of graphite, 37.6 kJ·mol -1 Low. Li / CFx is a solid-state lithium primary battery that was put on the market in the 1970s. Li / CFx batteries have a long shelf life and an annual capacity decay of less than 1%. They have very good safety and reliability and can operate normally over a wide temperature range. Therefore, they are widely used in a series of electronic devices such as fishing boat lighting, drone equipment, aerospace, medical equipment, emergency power supplies, etc. Using graphite fluoride as the active material for battery electrodes, the batteries produced have high energy density, a wide operating temperature range, high safety, and a capacity that is 5-10 times that of ordinary batteries.

[0003] In China, the production processes of graphite fluoride mainly include direct synthesis, catalytic synthesis and solid phase synthesis.

[0004] (1) Direct synthesis is the earliest synthesis method, which involves heating graphite and gaseous fluorine at a certain temperature.

[0005] (2) The catalytic synthesis method is to add a trace amount of metal fluoride as a catalyst to the reaction system of graphite and fluorine. The synthesis can be carried out below 300°C.

[0006] (3) The solid phase synthesis method is to mix a fluorinated solid polymer with graphite, heat it to a certain temperature under an inert atmosphere, and produce fluorinated graphite.

[0007] Patent CN106882804A discloses a method for preparing fluorinated graphite, which is mainly prepared by mixing fluoride molten salt and graphite pretreated with hydrofluoric acid, removing air and water in the reaction system with inert gas, and then heating and melting the fluoride molten salt, introducing a mixed gas of fluorine gas and argon gas, and reacting to obtain fluorinated graphite. This method can solve the problem of uneven contact between fluorine gas and graphite and large heat release in the traditional graphite preparation process, but the required temperature for the reaction is 500°C, the insulation time is 3h-8h, the process cycle is long, and the steps are relatively complicated.

[0008] Patent CN1544534A discloses a low-temperature production method of fluorinated graphite, which mainly involves soaking graphite in hydrochloric acid and hydrogen peroxide to obtain expanded graphite, reacting a certain concentration of fluorine gas and antimony powder in a closed container to obtain antimony pentafluoride, placing the expanded graphite and antimony pentafluoride in a closed container to react to obtain intercalated graphite; then placing the intercalated graphite in a closed reactor, introducing fluorine gas, and reacting to obtain fluorinated graphite. This method has a low reaction temperature and can be mass-produced, but the reaction time for preparing intercalated graphite is 9h-11h, and the reaction time for preparing fluorinated graphite is more than 7h, the production cycle is long, the production process is complicated, and the production efficiency is low.

[0009] Patent CN108190858A discloses a method for preparing fluorinated graphite, which is mainly prepared by uniformly mixing graphite, citrate and metal fluoride, introducing a mixed gas containing fluorine into the mixture and performing a fluorination reaction at 150°C to 250°C. This method can reduce the heat required for the reaction, and the fluorination reaction occurs at a lower temperature, thereby improving the reaction rate and selectivity, but it is easy to introduce impurities, which affects the product quality.

[0010] Patent CN101927981B discloses a method for preparing fluorinated graphite, which mainly uses an inorganic fluorinating agent and a graphite raw material to heat and react in the presence of high-purity nitrogen to obtain fluorinated graphite. The fluorinated graphite obtained by this method can reach a content of 59% and does not require external fluorine gas, but the reaction temperature of this method is relatively high and the fluorination rate of the reaction product is not high.

[0011] Patent CN104591115A discloses a low-temperature synthesis method of fluorinated graphite, which is mainly prepared by reacting graphite with antimony pentachloride to obtain antimony pentachloride graphite intercalation compound, and finally introducing fluorine nitrogen mixed gas for reaction to obtain fluorinated graphite. Although this method can be formed in ordinary fluorination equipment and has a large reaction temperature range, the reaction temperature is high, and the required reaction time is long, the production process is relatively cumbersome, and it is not conducive to industrial production. Several commonly used synthesis methods currently have high reaction temperatures, cumbersome processes, long production cycles, cumbersome production processes, low production efficiency, and are prone to introducing impurities, and the fluorination rate of the reaction product is not high. Summary of the invention

[0012] Based on this, the present invention proposes a low-temperature preparation method and preparation device of graphite fluoride, which solves the problems of the prior art.

[0013] According to a first aspect of the present invention, there is provided a low-temperature preparation method of graphite fluoride, comprising the following steps:

[0014] Add graphite raw materials into the high-pressure reactor, and evacuate and replace the high-pressure reactor and the piping system;

[0015] Slowly add liquid raw material ClF at a rate of 8-10 kg / h 3 and HF, setting the temperature in the autoclave to -10 to -20°C;

[0016] Pretreating the graphite raw material under a nitrogen atmosphere;

[0017] After the pretreatment is completed, the temperature in the high-pressure reactor is lowered to -10 to -20°C, and the pressure is adjusted;

[0018] The temperature in the high-pressure reactor is slowly raised to 150-200° C. at a rate of about 5° C. / min, and the reaction is carried out for 3-4 hours to obtain the fluorinated graphite.

[0019] According to an embodiment of the present invention, the graphite raw material is one of flake graphite and expanded graphite;

[0020] The graphite raw material is in the shape of a sphere, a block, a strip, a flake, or an irregular shape.

[0021] According to an embodiment of the present invention, the pretreatment of the graphite raw material under a nitrogen atmosphere comprises: after introducing high-purity nitrogen, slowly heating the high-pressure reactor to 40-50° C., and after the heating is completed, performing the pretreatment reaction for 2-3 hours.

[0022] According to an embodiment of the present invention, during the pretreatment, high-purity nitrogen is introduced into the high-pressure reactor until the pressure is 1 MPa to 2 MPa.

[0023] According to an embodiment of the present invention, the ClF 3 and the HF is supplied in liquid form;

[0024] The ClF 3 and the HF are stored in raw material steel cylinders respectively;

[0025] And the ClF 3 The HF is cooled in a deep freezer at a temperature of -10°C to 0°C.

[0026] According to an embodiment of the present invention, the ClF 3 The molar ratio with the raw graphite is 1:1 to 1:1.5;

[0027] The ClF 3 The molar ratio with the HF is 1:5 to 1:3.

[0028] According to an embodiment of the present invention, after the pretreatment is completed, the temperature in the high-pressure reactor is lowered to -10 to -20°C and the pressure is adjusted. The pressure adjustment includes: discharging part of the nitrogen to a pressure of 0.4 to 0.5 MPa.

[0029] According to an embodiment of the present invention, after obtaining the fluorinated graphite, the following steps are further included:

[0030] The temperature in the high-pressure reactor is cooled to room temperature, and the waste gas in the high-pressure reactor is discharged to the tail gas treatment system until the pressure drops to -70 kPa;

[0031] High-purity nitrogen was introduced into the autoclave to purge and replace the internal ClF 3 Mix with HF and repeat the purge and replacement multiple times.

[0032] According to an embodiment of the present invention, the high-pressure reactor is configured as a vacuum system, and the vacuum system is a combination of a vacuum generator vacuum system and a vacuum pump vacuum system.

[0033] According to an embodiment of the present invention, high-purity nitrogen is introduced into the high-pressure reactor to purge and replace the internal ClF 3 With HF mixture, repeated purge and replacement multiple times include:

[0034] First, use the vacuum generator to evacuate the vacuum system to -70kPa, then use the vacuum pump to evacuate to -90kPa, and then fill with nitrogen to equal pressure, thus completing a purge replacement;

[0035] Repeat the purge to replace the ClF in the autoclave. 3 Mix with HF 90 to 100 times.

[0036] According to a second aspect of the present invention, there is provided a preparation device for the above-mentioned low-temperature preparation method of graphite fluoride, comprising:

[0037] High pressure reactor;

[0038] An HF passage, connected to the inlet valve of the high-pressure reactor, comprises an HF cylinder, an HF solenoid valve and an HF flow controller connected in sequence;

[0039] CIF 3 passage, connected to the inlet valve of the high-pressure reactor, including ClF 3 Cylinder, ClF 3 Solenoid valve and ClF 3 Flow controller;

[0040] N 2 passage, connected to the N 2 valve;

[0041] The vacuum system comprises a vacuum generator vacuum system and a vacuum pump vacuum system connected to the outlet valve of the high-pressure reactor.

[0042] According to an embodiment of the present invention, the vacuum system is connected to an exhaust system via a pipeline, and an exhaust system solenoid valve is installed on the pipeline;

[0043] The vacuum generator system and the vacuum pump vacuum system are both connected to the pipeline;

[0044] The vacuum generator system includes a vacuum generator and a vacuum generator solenoid valve connected in sequence;

[0045] The vacuum generator is supplied with high-purity N 2 The solenoid valve is connected with high purity N 2 source;

[0046] The vacuum generator is connected to the exhaust system;

[0047] The vacuum pump vacuum system includes a vacuum pump connected through a vacuum pump solenoid valve.

[0048] It can be seen from the above technical scheme that the low-temperature preparation method and preparation device of graphite fluoride provided by the present invention have the following beneficial effects:

[0049] The present invention adopts ClF 3 Mixed with HF liquid to etch graphite raw materials. In liquid state, HF can effectively increase ClF 3 The dissociation degree of ClF 3 Reaction rate, better etching of graphite raw materials.

[0050] The present invention adopts ClF 3 As a fluorinating agent, ClF 3 It has extremely high corrosion resistance and can react well with graphite raw materials at low temperatures. Therefore, it can undergo fluorination reaction at low temperatures to generate fluorinated graphite. The reaction temperature is 150°C to 200°C. Compared with many methods for producing fluorinated graphite, it effectively reduces the reaction temperature and improves the inherent safety.

[0051] The vacuum system of the present invention adopts a combination of a vacuum generator vacuum system and a vacuum pump vacuum system. The vacuum generator has a simple structure and is connected to the tail gas system, which greatly reduces the corrosion of the system tail gas to the vacuum pump.

[0052] The pretreatment device and the reactor device used in the present invention are a common high-pressure reactor, the device structure is simple, the process flow is simple, the reaction time is short, and the efficiency of industrial production of fluorinated graphite is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A preparation device provided by an embodiment of the present invention.

[0054] In the picture: 1-HF cylinder; 2-ClF3 Cylinder; 3-HF solenoid valve; 4-HF flow controller; 5-ClF 3 Solenoid valve; 6-ClF 3 Flow controller; 7-inlet valve; 8-N 2 Valve; 9-export valve; 10-high pressure reactor; 11-high purity N 2 Solenoid valve; 12-vacuum generator; 13-vacuum generator solenoid valve; 14-vacuum pump solenoid valve; 15-exhaust system solenoid valve. DETAILED DESCRIPTION

[0055] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0056] According to a first aspect of the present invention, there is provided a low-temperature preparation method of graphite fluoride, comprising the following steps:

[0057] Add graphite raw materials into the high-pressure reactor, and evacuate and replace the high-pressure reactor and the piping system;

[0058] Slowly add liquid raw material ClF at a rate of 8-10 kg / h 3 and HF, setting the temperature in the autoclave to -10 to -20°C;

[0059] Pre-treating the graphite raw material under a nitrogen atmosphere;

[0060] After the pretreatment is completed, the temperature in the autoclave is lowered to -10 to -20°C and the pressure is adjusted;

[0061] The temperature in the high-pressure reactor is slowly raised to 150-200° C. at a rate of about 5° C. / min, and the reaction is carried out for 3-4 hours to obtain graphite fluoride.

[0062] According to an embodiment of the present invention, the high-pressure reactor is a cold and hot integrated machine, the high-pressure reactor has an excellent condensation effect, the power of condensation temperature control is very large, the temperature can be stably controlled, and the pressure and temperature will not rise suddenly. The liquid is added slowly rather than quickly, which effectively reduces the liquid raw material ClF 3 Risks of use with HF.

[0063] According to an embodiment of the present invention, the graphite raw material is one of flake graphite and expanded graphite;

[0064] The graphite raw material shape is spherical, block, strip, flake, and irregular.

[0065] According to an embodiment of the present invention, pre-treating the graphite raw material under a nitrogen atmosphere includes: after introducing high-purity nitrogen, slowly heating the high-pressure reactor to 40-50° C., and after the heating is completed, pre-treating the reaction for 2-3 hours.

[0066] According to the embodiment of the present invention, the graphite raw material can be formed into porous graphite through pretreatment, and the contact area between the fluorinating agent and the graphite raw material is increased, thereby effectively improving the fluorination rate and reaction rate.

[0067] According to an embodiment of the present invention, during the pretreatment, high-purity nitrogen is introduced into the high-pressure reactor until the pressure reaches 1 MPa to 2 MPa.

[0068] According to an embodiment of the present invention, ClF 3 and HF as liquid feed;

[0069] CIF 3 and HF are stored separately in raw material cylinders;

[0070] And ClF 3 and HF are cooled in a deep freezer at a temperature of -10℃~0℃.

[0071] According to an embodiment of the present invention, the present invention adopts ClF 3 As a fluorinating agent, it can effectively reduce the reaction temperature, and the use of HF and ClF 3 The mixed method can promote ClF 3 The two molecules of T-shaped structure combine to form an associated molecular structure with HF molecules, thereby effectively diluting ClF 3 .

[0072] According to an embodiment of the present invention, ClF 3 The molar ratio with the raw graphite is 1:1 to 1:1.5;

[0073] CIF 3 The molar ratio with HF is 1:5 to 1:3.

[0074] According to an embodiment of the present invention, after the pretreatment is completed, the temperature in the autoclave is lowered to -10 to -20°C and the pressure is adjusted. The pressure adjustment includes: discharging part of the nitrogen to a pressure of 0.4 to 0.5 MPa.

[0075] According to an embodiment of the present invention, after obtaining graphite fluoride, the following steps are further included:

[0076] The temperature in the high-pressure reactor is cooled down to room temperature, and the waste gas in the high-pressure reactor is discharged to the tail gas treatment system until the pressure drops to -70 kPa;

[0077] High-purity nitrogen was introduced into the high-pressure reactor to purge and replace the internal ClF 3Mix with HF and repeat the purge and replacement multiple times.

[0078] According to an embodiment of the present invention, the high-pressure reactor is configured as a vacuum system, and the vacuum system is a combination of a vacuum generator vacuum system and a vacuum pump vacuum system.

[0079] According to an embodiment of the present invention, high-purity nitrogen is introduced into the autoclave to purge and replace the internal ClF 3 With HF mixture, repeated purge and replacement multiple times include:

[0080] First, use the vacuum generator to evacuate the vacuum system to -70kPa, then use the vacuum pump to evacuate to -90kPa, and then fill with nitrogen to equal pressure, thus completing a purge replacement;

[0081] Repeated purging and replacement of ClF in the high-pressure reactor 3 Mix with HF 90 to 100 times.

[0082] According to a second aspect of the present invention, Figure 1 As shown, a preparation device for the above-mentioned low-temperature preparation method of graphite fluoride is provided, comprising:

[0083] High pressure reactor 10;

[0084] The HF passage is connected to the inlet valve 7 of the high-pressure reactor 10, and includes an HF cylinder 1, an HF solenoid valve 3 and an HF flow controller 4 connected in sequence;

[0085] CIF 3 passage, connected to the inlet valve 7 of the high-pressure reactor 10, including ClF 3 Cylinder 2, ClF 3 Solenoid valve 5 and ClF 3 Flow controller 6;

[0086] N 2 Passage, connected to the N of the high pressure reactor 10 2 Valve 8;

[0087] The vacuum system includes a vacuum generator vacuum system connected to the outlet valve 9 of the high-pressure reactor 10 and a vacuum pump vacuum system.

[0088] According to an embodiment of the present invention, the vacuum system is connected to the exhaust system through a pipeline, and an exhaust system solenoid valve 15 is installed on the pipeline;

[0089] The vacuum generator system and the vacuum pump vacuum system are both connected to the pipeline;

[0090] The vacuum generator system includes a vacuum generator 12 and a vacuum generator solenoid valve 13 connected in sequence;

[0091] The vacuum generator is passed through high purity N 2 Solenoid valve 11 is connected to a high purity N 2 source;

[0092] The vacuum generator is connected to the exhaust system;

[0093] Vacuum Pump The vacuum system includes a vacuum pump connected via a vacuum pump solenoid valve 14 .

[0094] The vacuum system of the present invention adopts a combination of a vacuum generator vacuum system and a vacuum pump vacuum system. The vacuum generator has a simple structure and is connected to the tail gas system, which greatly reduces the corrosion of the system tail gas to the vacuum pump.

[0095] The pretreatment device and the reactor device used in the present invention are a common high-pressure reactor, the device structure is simple, the process flow is simple, the reaction time is short, and the efficiency of industrial production of fluorinated graphite is greatly improved.

[0096] The technical solution of the present invention is described in detail below through preferred embodiments. It should be noted that the specific embodiments below are only used for illustration and are not used to limit the present invention.

[0097] Example 1

[0098] Add 5 kg of flake graphite raw material into the autoclave, and set the temperature of the autoclave's hot and cold integrated machine to -10°C;

[0099] After adding flake graphite, close the pipeline valve, open the vacuum pump vacuum system, and evacuate and replace the high-pressure reactor and pipeline system 80 times;

[0100] After the vacuum replacement is completed, slowly add 38kgClF of liquid raw material at a rate of (8-10)kg / h 3 and 40kgHF, and set the temperature of the high-pressure reactor cooling and heating integrated machine to -10℃;

[0101] After the addition is completed, 1MPa high-purity nitrogen is introduced to make the system pressure reach 1MPa;

[0102] After the high-purity nitrogen was introduced, the temperature of the autoclave was slowly raised to 40°C at a rate of about 1°C / min. After the temperature was raised, the pretreatment reaction was carried out for 2h.

[0103] After the pretreatment is completed, set the temperature of the hot and cold machine to -10℃ to cool down;

[0104] Open the vacuum system of the vacuum generator and exhaust some nitrogen to a pressure of 0.5 MPa;

[0105] After the pressure adjustment was completed, the system was slowly heated to 150°C at a rate of about 5°C / min and reacted for 3h;

[0106] After the reaction is completed, the temperature is lowered to room temperature, the vacuum system of the vacuum generator is turned on, and the waste gas in the high-pressure reactor is discharged to the tail gas treatment system until the pressure drops to about -70kPa.

[0107] Introduce high-purity nitrogen into the autoclave until the pressure is balanced, then open the vacuum system of the vacuum generator to reduce the system pressure to -70 kPa, and then open the vacuum system of the vacuum pump to reduce the system pressure to -90 kPa. This completes a purge to replace the internal ClF 3 The mixture was mixed with HF for 90 times, and when the HF content of the tail gas was detected to be lower than 3 ppm, the fluorinated graphite product was obtained, and its fluorine content was detected to be F:C=0.80.

[0108] Example 2

[0109] Add 3 kg of flake graphite raw material into the autoclave, and set the temperature of the autoclave's hot and cold integrated machine to -6°C;

[0110] After adding flake graphite, close the pipeline valve, open the vacuum pump vacuum system, and evacuate and replace the high-pressure reactor and pipeline system 80 times;

[0111] After the vacuum replacement is completed, slowly add 23kgClF liquid raw material at a rate of (8-10)kg / h 3 and 40kgHF, and set the temperature of the high-pressure reactor cooling and heating integrated machine to -6°C;

[0112] After the addition is completed, 1MPa high-purity nitrogen is introduced to make the system pressure reach 1MPa;

[0113] After the high-purity nitrogen was introduced, the temperature of the autoclave was slowly raised to 40°C at a rate of about 1°C / min. After the temperature was raised, the pretreatment reaction was carried out for 2h.

[0114] After the pretreatment is completed, set the temperature of the hot and cold machine to -6°C to cool down;

[0115] Open the vacuum system of the vacuum generator and exhaust some nitrogen to a pressure of 0.5 MPa;

[0116] After the pressure adjustment was completed, the system was slowly heated to 175°C at a rate of about 5°C / min and reacted for 3h;

[0117] After the reaction is completed, the temperature is lowered to room temperature, the vacuum system of the vacuum generator is turned on, and the waste gas in the high-pressure reactor is discharged to the tail gas treatment system until the pressure drops to about -70kPa.

[0118] Introduce high-purity nitrogen into the autoclave until the pressure is balanced, then open the vacuum system of the vacuum generator to reduce the system pressure to -70 kPa, and then open the vacuum system of the vacuum pump to reduce the system pressure to -90 kPa. This completes a purge to replace the internal ClF 3 The mixture was mixed with HF for 90 times, and when the HF content of the tail gas was detected to be lower than 3 ppm, the fluorinated graphite product was obtained, and its fluorine content was detected to be F:C=0.75.

[0119] Example 3

[0120] Add 3 kg of flake graphite raw material into the autoclave, and set the temperature of the autoclave's hot and cold integrated machine to -8°C;

[0121] After adding flake graphite, close the pipeline valve, open the vacuum pump vacuum system, and evacuate and replace the high-pressure reactor and pipeline system 80 times;

[0122] After the vacuum replacement is completed, slowly add 23kgClF liquid raw material at a rate of (8-10)kg / h 3 and 40kgHF, and set the temperature of the high-pressure reactor cooling and heating integrated machine to -8°C;

[0123] After the addition is completed, 1MPa high-purity nitrogen is introduced to make the system pressure reach 1MPa;

[0124] After the high-purity nitrogen was introduced, the temperature of the autoclave was slowly raised to 40°C at a rate of about 1°C / min. After the temperature was raised, the pretreatment reaction was carried out for 2h.

[0125] After the pretreatment is completed, set the temperature of the hot and cold machine to -8℃ to cool down;

[0126] Open the vacuum system of the vacuum generator and exhaust some nitrogen to a pressure of 0.5 MPa;

[0127] After the pressure adjustment, the system was slowly heated to 200 °C at a rate of about 5 °C / min and reacted for 3 h;

[0128] After the reaction is completed, the temperature is lowered to room temperature, the vacuum system of the vacuum generator is turned on, and the waste gas in the high-pressure reactor is discharged to the tail gas treatment system until the pressure drops to about -70kPa.

[0129] Introduce high-purity nitrogen into the autoclave until the pressure is balanced, then open the vacuum system of the vacuum generator to reduce the system pressure to -70 kPa, and then open the vacuum system of the vacuum pump to reduce the system pressure to -90 kPa. This completes a purge to replace the internal ClF 3 The mixture was mixed with HF for 90 times, and when the HF content of the tail gas was detected to be lower than 3 ppm, the fluorinated graphite product was obtained, and its fluorine content was detected to be F:C=0.73.

[0130] Comparative Example 1

[0131] Place flake graphite in 50% hydrofluoric acid and let it stand for 24 hours to separate into layers, then pour off the upper layer of hydrofluoric acid, add water, stir, let it stand to separate into layers, and pour off the upper layer of water. Use water to wash the graphite repeatedly until the pH value of the washed water is neutral. Dry the graphite in a 150°C forced air drying oven for 12 hours, and then dry it in a 150°C vacuum drying oven for 8 hours. Add the pretreated graphite to a fluidized bed reactor and let it stand; pass high-purity nitrogen into the fluidized bed reactor to remove water and oxygen until the water and oxygen contents in the fluidized bed reactor are less than 10ppm and 100ppm, respectively;

[0132] Subsequently, the temperature of the autoclave was set to 200°C and heated, and the temperature was kept for 2 hours; at the end of the insulation, the atmosphere in the autoclave was replaced with pure argon; the autoclave was heated again, the temperature was increased from 200°C to 400°C, and the temperature was kept for 2 hours; at the end of the insulation, the atmosphere in the autoclave was replaced with pure argon again to remove the water generated during the heating process.

[0133] Continue to heat the autoclave to 500°C, start to introduce 15% (volume ratio) of fluorine-nitrogen mixed gas (i.e., the volume ratio of fluorine source to inert gas is 0.15:1), and after 5 hours of reaction, stop introducing the fluorine-nitrogen mixed gas, introduce nitrogen into the fluidized bed for replacement, and remove the residual fluorine gas in the fluidized bed. When the fluorine content in the tail gas is detected to be below 3ppm, stop blowing nitrogen, the fluorination reaction is terminated, and the final sample is obtained, and its fluorine content is detected to be F:C=0.62.

[0134] By comparing the preparation methods and samples in Examples 1-3 and Comparative Example 1, it can be seen that the preparation method provided by the present invention has low reaction temperature, simple process, short production cycle, high production efficiency, and the fluorination rate of the reaction product is also higher than that of the general method.

[0135] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low-temperature preparation method of graphite fluoride, characterized in that: The following steps are involved: Add graphite raw materials into the high-pressure reactor, and evacuate and replace the high-pressure reactor and the piping system; Slowly add liquid raw materials ClF3 and HF at a rate of 8-10 kg / h, and set the temperature in the autoclave to -10--20°C; Pretreating the graphite raw material under a nitrogen atmosphere; After the pretreatment is completed, the temperature in the high-pressure reactor is lowered to -10 to -20°C, and the pressure is adjusted; The temperature in the high-pressure reactor is slowly raised to 150-200° C. at a rate of about 5° C. / min, and the reaction is carried out for 3-4 hours to obtain the fluorinated graphite.

2. The low temperature preparation method according to claim 1, characterized in that: The graphite raw material is one of flake graphite and expanded graphite; The graphite raw material is in the shape of a sphere, a block, a strip, a flake, or an irregular shape.

3. The low temperature preparation method according to claim 1, characterized in that: The pretreatment of the graphite raw material under nitrogen atmosphere comprises: after introducing high-purity nitrogen, slowly heating the high-pressure reactor to 40-50° C., and after the heating is completed, pretreatment reaction for 2-3 hours; During the pretreatment, high-purity nitrogen is introduced until the pressure in the high-pressure reactor reaches 1 MPa to 2 MPa.

4. The low temperature preparation method according to claim 1, characterized in that: The ClF3 and the HF are liquid feeds; The ClF3 and the HF are stored in raw material steel cylinders respectively; The ClF3 and HF are cooled in a cryogenic box at a temperature of -10°C to 0°C; The molar ratio of ClF3 to the raw graphite is 1:1 to 1:1.5; The molar ratio of the ClF3 to the HF is 1:5 to 1:

3.

5. The low temperature preparation method according to claim 1, characterized in that: After the pretreatment is completed, the temperature in the autoclave is lowered to -10 to -20°C and the pressure is adjusted. The pressure adjustment includes: discharging part of the nitrogen until the pressure is 0.4 to 0.5 MPa.

6. The low temperature preparation method according to claim 1, characterized in that: After obtaining the graphite fluoride, the method further comprises the following steps: The temperature in the high-pressure reactor is cooled to room temperature, and the waste gas in the high-pressure reactor is discharged to the tail gas treatment system until the pressure drops to -70 kPa; High-purity nitrogen was introduced into the high-pressure reactor to purge and replace the internal ClF3 and HF mixture, and the purge and replacement were repeated multiple times.

7. The low-temperature preparation method according to claim 6, characterized in that: The high-pressure reactor is configured as a vacuum system, and the vacuum system is a combination of a vacuum generator vacuum system and a vacuum pump vacuum system.

8. The low temperature preparation method according to claim 7, characterized in that: The step of introducing high-purity nitrogen into the autoclave to purge and replace the internal ClF3 and HF mixture, and repeating the purge and replacement multiple times comprises: First, use the vacuum generator to evacuate the vacuum system to -70kPa, then use the vacuum pump to evacuate to -90kPa, and then fill with nitrogen to equal pressure, thus completing a purge replacement; The purge and replacement of the ClF3 and HF mixture in the autoclave was repeated 90 to 100 times.

9. A preparation device for the low-temperature preparation method of graphite fluoride according to any one of claims 1 to 8, characterized in that: include: High pressure reactor; An HF passage, connected to the inlet valve of the high-pressure reactor, comprises an HF cylinder, an HF solenoid valve and an HF flow controller connected in sequence; A ClF3 passage connected to the inlet valve of the high-pressure reactor includes a ClF3 cylinder, a ClF3 solenoid valve and a ClF3 flow controller connected in sequence; A N2 passage connected to the N2 valve of the high-pressure reactor; The vacuum system comprises a vacuum generator vacuum system and a vacuum pump vacuum system connected to the outlet valve of the high-pressure reactor.

10. The preparation device according to claim 9, characterized in that: The vacuum system is connected to the exhaust system through a pipeline, and an exhaust system solenoid valve is installed on the pipeline; The vacuum generator system and the vacuum pump vacuum system are both connected to the pipeline; The vacuum generator system includes a vacuum generator and a vacuum generator solenoid valve connected in sequence; The vacuum generator is connected to a high-purity N2 source via a high-purity N2 solenoid valve; The vacuum generator is connected to the exhaust system; The vacuum pump vacuum system includes a vacuum pump connected through a vacuum pump solenoid valve.

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