Process device and process method for preparing graphene

Abstract

The invention discloses a process device for preparing graphene and a process method thereof. The process device comprises a microwave unit, the microwave unit comprises a feeding section, a microwave section and a discharging section which are horizontally communicated in sequence; the feeding section comprises a horizontally arranged microwave suppression pipe I, the fixed end of the microwave suppression pipe I is communicated with the microwave section, and an air inlet pipe is arranged in the microwave suppression pipe I; the feeding section further comprises a feeding pipe, the feeding pipe is communicated with the air inlet pipe at a certain angle, and a feeding port I of the feeding pipe is located above the microwave suppression pipe I. According to the process method provided by the invention, continuous feeding is carried out on the microwave process in a manner that gravity blanking is matched with an air compressor to carry out gas conveying, so that the time cost is saved; no special atmosphere environment is needed in the microwave area, the air environment can meet the production conditions, and the shielding gas cost is saved.

Description

TECHNICAL FIELD

[0001] The application relates to a process device for preparing graphene and a process method thereof, and belongs to the technical field of graphene. BACKGROUND

[0002] Due to the two-dimensional few-layer crystal structure of graphene, graphene exhibits excellent electron transport capacity and heat conduction capacity. Graphene has a wide application prospect in the fields of humanoid robots, new energy batteries, functional coatings, conductive inks, rubber tires, lubricating oils and the like. With the discovery of graphene, the preparation method of graphene has become the main research direction of the industry.

[0003] The mainstream graphene preparation methods include an oxidation graphite reduction method (Hummers method) and a chemical vapor deposition method (CVD method). The Hummers method is to first oxidize graphite into graphite oxide by using strong oxidants such as concentrated sulfuric acid, concentrated nitric acid and potassium permanganate, then peel off the graphite oxide into graphene oxide through ultrasonic treatment, and then obtain graphene powder through dialysis purification and reduction. The Hummers method has a long process cycle and serious pollution, and the graphene obtained by the Hummers method has the defects of many defects and poor quality, which limits its application in high-end scenarios. The CVD method has high quality of the prepared graphene, but has the disadvantages of complex process and high cost, and is difficult to be applied in large-scale industrialization.

[0004] The microwave exfoliation method graphene refers to the use of the huge energy released by the gasification effect of microwaves to exfoliate graphite layers to prepare graphene. Moreover, the preparation method has the advantages of high efficiency and greenness, and has great potential in the field of large-scale rapid preparation of graphene.

[0005] The existing microwave method graphene production process has the problems of high power (more than 20 kW), high temperature (about 500 DEG C), easy aging (plastic reactor is not resistant to high temperature), intermittent production (pulse feeding, static sintering, and certain waiting time), large energy consumption, inability to realize continuous production, relatively low yield, and the like. Some production processes need to be protected by atmosphere during work. The above problems greatly increase the production cost of graphene and greatly restrict the yield of graphene. SUMMARY

[0006] In order to solve the problems existing in the prior art, the application provides a new microwave method graphene production equipment and process method.

[0007] In one aspect of the application, a process device for preparing graphene is provided, and the process device comprises a microwave unit.

[0008] The microwave unit comprises a feeding section, a microwave section and a discharging section which are sequentially and horizontally communicated.

[0009] The feeding section comprises a horizontally arranged microwave suppression tube I, a fixed end of the microwave suppression tube I being in communication with the microwave section, and an air inlet pipe being arranged in the microwave suppression tube I;

[0010] The feeding section further comprises a feeding pipe, the feeding pipe being in communication with the air inlet pipe, and a feeding port I of the feeding pipe being located above the microwave suppression tube I; the air inlet pipe is provided with an air inlet port and an air outlet port;

[0011] The microwave section is provided with a microwave cavity, the microwave cavity being provided with a microwave irradiation area; the microwave cavity is provided with an expansion pipe, and the air outlet port is in communication with the expansion pipe;

[0012] The discharging section comprises a horizontally arranged microwave suppression tube II, a fixed end of the microwave suppression tube II being in communication with the microwave section, the microwave suppression tube II being provided with a discharging pipe, a feeding port II of the discharging pipe being in communication with the expansion pipe, and a free end of the discharging pipe being provided with a discharging port.

[0013] Optionally, taking the microwave cavity as a horizontal line and the air inlet port as an initial point, the inclination angles of the air inlet pipe, the feeding pipe and the discharging pipe satisfy the following conditions in a clockwise direction:

[0014] The inclination angle of the air inlet pipe is 0°-90° or 270°-360°;

[0015] The inclination angle of the feeding pipe is 45°-90°;

[0016] The inclination angle of the discharging pipe is 120°-240°.

[0017] Optionally, the process device further comprises a pneumatic conveying module, the pneumatic conveying module being in communication with the air inlet port.

[0018] Optionally, in the process device,

[0019] The pipe cross-sectional area of the air inlet pipe is 0.5-3 cm 2 ;

[0020] The pipe cross-sectional area of the feeding pipe is 0.5-3 cm 2 ;

[0021] The pipe cross-sectional area of the expansion pipe is 1-30 cm 2 ;

[0022] The pipe cross-sectional area of the discharging pipe is 1-30 cm 2 .

[0023] Optionally, in the process device, the gas inlet pipe, the feed pipe, the expansion pipe and the discharge pipe are communicated to form a material flow chamber, and the material flow chamber is made of quartz, ceramic or the like, preferably quartz; and the cross-sectional areas of the feed pipe, the gas inlet pipe, the expansion pipe and the discharge pipe are 2 cm 2 , 2 cm 2 , 16.6 cm 2 , 16.6 cm 2 .

[0024] Optionally, the process device further comprises an automatic feeding machine, which is in communication with the feed inlet I.

[0025] The automatic feeding machine is a feeding device composed of at least one of a vibrating feeder, a gravimetric feeder, a volumetric auger-type feeder, a syringe, a compressed air-assisted feeder, a vacuum-assisted feeder, a gravity feeder, a drum feeder, a wheel feeder, a slide rail, a chute and a conveyor-type feeder.

[0026] Specifically, the above-mentioned feeding machine comprises a feeder device selected from a loss-in-weight feeder, a vibrating feeder, a gravimetric feeder, a volumetric auger-type feeder, a syringe, a compressed air-assisted feeder, a vacuum-assisted feeder, a gravity feeder, a drum feeder, a wheel feeder, a slide rail, a chute, a conveyor-type feeder or a combination thereof.

[0027] Optionally, the microwave section has a microwave cavity in the shape of a cuboid.

[0028] The upper surface of the microwave cavity is provided with a microwave window.

[0029] The microwave section is further provided with a waveguide, which is provided with a microwave inlet and a microwave outlet, and the microwave outlet is connected to the microwave window.

[0030] Optionally, the microwave section is further provided with a microwave generator, and the microwave inlet is connected to the microwave generator.

[0031] Optionally, the microwave section is further provided with an infrared temperature measurement module for monitoring the temperature in the microwave irradiation area.

[0032] Specifically, the process device is provided with an infrared temperature measurement module, which can be used to monitor the reaction temperature of the intercalation modified graphite sample under microwave irradiation, so as to monitor the stability of the process.

[0033] Optionally, on the microwave section, the cavity wall near the end of the discharge port is further provided with a waste gas exhaust port.

[0034] Specifically, the process device comprises a device allowing the exhaust gas to exit or a scrubber device capturing the exhaust gas. The process device has a discharging module with a bottom suction container at the discharging port. The powder sample obtained in the suction device is the graphene product.

[0035] In another aspect of the present application, a process method for preparing graphene is provided, which uses the process device described above.

[0036] The process method comprises:

[0037] (1) Pretreatment: soaking graphite I in an intercalation agent solution containing an intercalation agent, sealing and storing, drying, and obtaining intercalation-modified graphite II;

[0038] (2) Pushing the graphite II obtained in step (1) to the feeding port I, and using the gas entering through the gas inlet to transport the graphite II into the microwave irradiation zone in the microwave range to occur a physical reaction and obtain graphene.

[0039] Optionally, in step (1), the intercalation agent solution comprises a polar solvent.

[0040] The polar solvent is selected from 1-4 kinds of water, methanol, ethanol, propanol, ethylene glycol, and glycerol.

[0041] The volume ratio of each component is 0-1:0-1:0-1:0-1.

[0042] Optionally, the intercalation agent is at least one of bromine, chlorine, and iodine.

[0043] Optionally, the volume ratio of the intercalation agent to the polar solvent is 1-100:1-100.

[0044] Optionally, the volume ratio of the intercalation agent solution to the graphite I is 1:10-10:1.

[0045] Optionally, the volume ratio of the intercalation agent solution to the graphite I is 1:5.

[0046] Optionally, the graphite I is selected from at least one of artificial graphite and natural graphite.

[0047] Optionally, the natural graphite mainly comprises flake graphite and earthy graphite.

[0048] Optionally, the graphite I is selected from natural flake graphite.

[0049] Optionally, the particle size of the natural flake graphite is 50 mesh.

[0050] Optionally, the sealing and storing time is 12-120 hours.

[0051] Optionally, the soaking time is 6h-336h.

[0052] Optionally, in step (1), the solid content of the intercalation modified graphite II is 50-80%.

[0053] Optionally, the solid content of the intercalation modified graphite II is 60-80%.

[0054] Optionally, the solid content of the intercalation modified graphite II is 70%.

[0055] Optionally, in step (2), the feeding speed of graphite II is 0.1-100g / min.

[0056] Optionally, in step (2), the feeding speed of graphite II is 35-40g / min.

[0057] Optionally, the transmission rate of the chain plate is 40g / min.

[0058] Optionally, the pressure of the gas is 0.01-0.25MPa;

[0059] The flow rate of the gas is 100-200L / min;

[0060] Optionally, the gas is air.

[0061] Optionally, the pressure of the gas is 0.05MPa.

[0062] Optionally, the flow rate of the gas is 150L / min.

[0063] Optionally, the microwave power in the microwave band is 1-300kW.

[0064] Optionally, the microwave power in the microwave band is 6-10kW.

[0065] Optionally, the temperature of the reaction is 200-500℃.

[0066] Optionally, the residence time of the graphite II in the microwave irradiation zone is 2-12s.

[0067] Optionally, the expansion ratio of the graphene is ≥80 times.

[0068] Optionally, the expansion ratio of the graphene is ≥100 times.

[0069] Optionally, the number of layers of the graphene is ≤5 layers.

[0070] Optionally, the number of layers of the graphene is ≤3 layers.

[0071] Optionally, the ratio of the intensity of the D peak to the intensity of the G peak (I D / I G ≤0.2.

[0072] Optionally, the ratio of the intensity of the D peak to the intensity of the G peak (I D / I G ≤0.05.

[0073] As a specific embodiment, the process for preparing graphene in the present application comprises:

[0074] 1. Preparation of intercalated graphite:

[0075] The dispersant is configured, and a polar solvent is optionally selected: water, methanol, ethanol, propanol, ethylene glycol, glycerol and other alcohol substances; any 1-4 solvents above are used as the dispersant, and the volume ratio is 0-1:0-1:0-1:0-1, preferably, the volume ratio of water, methanol, ethanol and propanol is 1:0:0:0.

[0076] The intercalation agent solution is prepared, and bromine is added to the dispersant as the intercalation agent, and the volume ratio is 1-100:1-100; preferably, the volume ratio of bromine to dispersant is 5:95.

[0077] The intercalation agent solution is used for soaking pretreatment of graphite. After the intercalation agent solution is introduced into the graphite, it is sealed and stored for more than 12 hours, and preferably for 72 hours. At the same time, stirring is carried out, and the stirring speed is 5 revolutions / minute or more, and preferably 20 revolutions / minute. After stirring is completed, graphite A solution is obtained. After the above dispersion is filtered and air-dried, intercalation modified graphite is obtained.

[0078] 2. Preparation of fluffy graphene:

[0079] The above intercalation modified graphite B is pushed to the microwave feeding port through an automatic feeding machine. The pneumatic conveying module is connected to the air inlet of the material flow bin, and the graphite B is sprayed to the microwave irradiation area through pneumatic conveying. The graphite B stays in the microwave irradiation area for a period of time and then leaves, and the graphene product is obtained.

[0080] The above graphene product is grayish white and fluffy. The expansion ratio of the graphene product compared with the raw material graphite is ≥80 times, and preferably the expansion ratio is ≥100 times. Through a transmission electron microscope or a Raman device, the number of layers of the above graphene product is ≤5 layers, and preferably the number of layers of the graphene product is ≤3 layers. Through Raman spectrum characterization, the ratio of the intensity of the D peak to the intensity of the G peak (I D / I G ) of the graphene is ≤0.2, preferably I D / I G ≤0.05, and more preferably I D / I G =0.

[0081] 3. Preparation of powdered graphene

[0082] The above-mentioned off-white and fluffy graphene can be prepared into powdered graphene by mechanical shearing treatment. The mechanical shearing treatment includes using air jet milling, ball milling, rotary blade mechanical shearing, ultrasonic treatment, cavitation or a combination thereof, and preferably, using an air jet mill for mechanical shearing treatment. After mechanical shearing treatment, the number of layers of graphene remains substantially unchanged, and no defects are formed, and its I D / I G ≤0.2.

[0083] The beneficial effects that can be produced by the present application include:

[0084] 1) The process provided by the present application is simple, low in energy consumption, green, pollution-free, high in product quality, defect-free, can realize continuous production, and has large output;

[0085] 2) The process provided by the present application uses the way of gravity feeding combined with air compressor for gas delivery to continuously feed the microwave process, saving time cost; there is no need for special atmosphere environment in the microwave zone, and air environment can meet the production conditions, saving the cost of protective gas;

[0086] 3) The process provided by the present application has very small output power, low temperature, and a unit mass of graphite only needs to stay in the microwave zone for a few seconds to expand into graphene compared with existing microwave equipment, saving several times of power cost; and has high quality, no defects, low layer number, and extremely large output;

[0087] 4) The process provided by the present application has simple device structure and small size, greatly reducing the floor area of the device and saving the site cost; at the same time, one person can operate and monitor 2-3 devices instead of several people operating and monitoring one device, greatly reducing the labor cost. BRIEF DESCRIPTION OF DRAWINGS

[0088] Figure 1 is the process flow chart of graphene in the embodiment of the present application;

[0089] Figure 2 is the process system flow chart of graphene in the embodiment of the present application;

[0090] Figure 3 is the assembly drawing of the microwave unit in the process device for preparing graphene in the embodiment of the present application;

[0091] Figure 4 is the longitudinal cut drawing of the microwave unit in the process device for preparing graphene in the embodiment of the present application;

[0092] Figure 5 Structure diagram of the structure at the observation window in the micro-wave unit of the embodiment of the present application;

[0093] Figure 6 Structure diagram of the structure at the observation window in the micro-wave unit of the embodiment of the present application;

[0094] Figure 7 Structure diagram of the microwave suppression tube I in the micro-wave unit of the embodiment of the present application;

[0095] Figure 8 Structure diagram of the microwave suppression tube II in the micro-wave unit of the embodiment of the present application;

[0096] Figure 9 Structure diagram of the waveguide tube in the micro-wave unit of the embodiment of the present application;

[0097] Figure 10 Structure diagram of the microwave cavity in the micro-wave unit of the embodiment of the present application;

[0098] Figure 11 Structure diagram of the material flow chamber in the micro-wave unit of the embodiment of the present application;

[0099] Figure 12 Structure diagram of the suppression plate side plate in the micro-wave unit of the embodiment of the present application;

[0100] Figure 13 Structure diagram of the mica plate in the micro-wave unit of the embodiment of the present application.

[0101] Figure 14 Raman spectrum I obtained in Example 2 of the present application.

[0102] Figure 15 Raman spectrum II obtained in Example 2 of the present application.

[0103] Figure 16 Transmission electron microscope image I obtained in Example 2 of the present application, in which the scale is 5 nm.

[0104] Figure 17 Transmission electron microscope image II obtained in Example 2 of the present application, in which the scale is 5 nm.

[0105] List of components and reference numerals:

[0106] 1, feed inlet I 2, air inlet 3, microwave suppression tube I

[0107] 4, microwave cavity 5, waveguide tube 6, infrared temperature measurement module

[0108] 7, mica plate 8, observation window 9, microwave irradiation area

[0109] 10, exhaust port 11, material flow bin 12, microwave suppression tube II

[0110] 13, discharge port 14, feeding pipe 15, air inlet pipe

[0111] 16, expansion pipe 17, discharge pipe 18, observation window glass plate

[0112] 19, observation window hollow plate DETAILED DESCRIPTION

[0113] The present application will be described in detail below with reference to examples, but the present application is not limited to these examples.

[0114] Unless otherwise specified, the raw materials in the examples of the present application are purchased through commercial channels.

[0115] The analysis method in the examples of the present application is as follows:

[0116] Raman spectroscopy is used to analyze graphene, obtain a spectrum in the range of 200-3250 cm -1 and fit to obtain I D / I G value, I 2D / I G value, judge the defects and number of layers of graphene;

[0117] Transmission electron microscopy is used to analyze graphene to determine the number of layers of graphene.

[0118] In the present application, the preparation method of graphene includes:

[0119] (1) intercalation modification technology of graphite, i.e. formulation of intercalation agent and pretreatment process of graphite;

[0120] (2) microwave reaction system technology, including automatic feeding module, pneumatic conveying continuous expansion technology, reaction cavity temperature measurement module, discharging module and waste gas absorption module;

[0121] (3) crushing technology of fluffy graphene.

[0122] According to an embodiment of the present application, the process flow chart is as shown in Figure 1 , including the following steps:

[0123] Pretreatment: graphite A is soaked with intercalation agent to form a graphite A solution;

[0124] Filtration and drying: solid-liquid separation is performed on the graphite A solution, and then the surface of the graphite is dried to remove residual liquid to obtain graphite B;

[0125] Microwave feeding: the material is transported to the microwave device by pneumatic conveying, the treated graphite B reaches the microwave zone under the push of compressed air, and the physical expansion is completed after a short period of time to form graphene A; the subsequent compressed air blows graphene A out of the microwave device to reach the material receiving bin;

[0126] Crushing: graphene A is sent into an air jet mill for crushing to obtain graphene B, and graphene B is wet ground (sanding machine) with a dispersant according to different particle size requirements of the user to obtain graphene C; graphene B is mechanically ground to form graphene D according to different particle size requirements of the user.

[0127] Example 1

[0128] A process device for preparing graphene, the process device comprising a microwave unit, as shown in Figure 3 , as shown in Figure 4 , the microwave unit comprising a feeding section, a microwave section, and a discharging section in sequence and horizontally communicating;

[0129] The feeding section comprises a microwave suppression tube I 3 arranged horizontally, as shown in Figure 7 , a fixed end of the microwave suppression tube I 3 communicates with the microwave section, and an air inlet pipe 15 is arranged in the microwave suppression tube I 3;

[0130] The feeding section further comprises a feeding pipe 14, the feeding pipe 14 vertically communicates with the air inlet pipe 15, and a feeding port I1 of the feeding pipe is located above the microwave suppression tube I 3; the air inlet pipe 15 is provided with an air inlet port 2 and an air outlet port;

[0131] The microwave section is provided with a microwave cavity 4, as shown in Figure 10 a and b, the microwave cavity is formed in the shape of a cuboid by assembling suppression plates, and a microwave irradiation zone 9 is arranged in the microwave cavity 4; an expansion pipe 16 is arranged in the microwave cavity 4, the air outlet port communicates with the expansion pipe 16, a microwave window is arranged on an upper surface of the microwave cavity 4; the microwave section is further provided with a waveguide 5, as shown in Figure 9 , the waveguide 5 is provided with a microwave inlet port and a microwave outlet port, the microwave outlet port is connected with the microwave window, and a mica plate 7, as shown in Figure 13 , is further arranged between the waveguide and the microwave cavity;

[0132] The discharging section comprises a microwave suppression tube II 12 arranged horizontally, as shown in Figure 8 , a fixed end of the microwave suppression tube II 12 communicates with the microwave section, an outlet pipe 17 is arranged in the microwave suppression tube II 12, a feeding port II of the outlet pipe 17 communicates with the expansion pipe 16, and a free end of the outlet pipe 17 is provided with a discharging port 13.

[0133] The air inlet pipe 15, the feed pipe 14, the expansion pipe 16 and the discharge pipe 17 are communicated to form a material flow chamber 11 (as shown in Figure 11 ), and the material flow chamber 11 is made of quartz, and the cross-sectional areas of the feed pipe 14, the air inlet pipe 15, the expansion pipe 16 and the discharge pipe 17 are 2 cm 2 , 2 cm 2 , 16.6 cm 2 , 16.6 cm 2 , respectively.

[0134] The microwave section is also provided with a microwave generator (a microwave source as shown in Figure 2 ), and the microwave inlet is connected with the microwave generator.

[0135] The microwave section is also provided with an infrared temperature measurement module 6 for monitoring the reaction temperature of the intercalation modified graphite sample under microwave irradiation, so as to monitor the stability of the process.

[0136] On the cavity wall of the microwave section near the end of the discharge port, a waste gas exhaust port 10 is also arranged.

[0137] On the side plate (as shown in Figure 12 ) of the suppression plate, an observation window 8 is arranged, which is composed of an observation window glass plate 18 (as shown in Figure 6 ) and an observation window hollow plate 19, as shown in Figure 5 .

[0138] The process device, as shown in the process system flow chart, further comprises a feed bin in communication with the feed port I, and the feed bin in this embodiment is made of quartz. Figure 2 The process device further comprises a pneumatic conveying module in communication with the air inlet port, and the pneumatic conveying module comprises an air compressor, an air storage tank, a filter and a pressure valve.

[0139] The process device comprises a waste gas recovery module, specifically a device allowing waste gas to exit or a scrubber device capturing waste gas, connected with the waste gas exhaust port 10.

[0140] The process device is also provided with a material collection bin at the discharge port.

[0141] The process device further comprises a crushing module connected with the material collection bin and the pneumatic conveying module, and a jet mill is used to mechanically shear the graphene.

[0142] Example 2

[0143] The process device obtained in Example 1 is used to prepare graphene according to the process of

[0144] , Figure 1 Figure 2 , and the specific steps are as follows:​

[0145] 1. Preparation of intercalated graphite:

[0146] (1) Dispersant was configured, and 98 ml of water was selected as the dispersant;

[0147] (2) Intercalation agent solution was prepared, and 2 ml of bromine intercalation agent was added to the dispersant, with a volume concentration of 2%;

[0148] (3) The intercalation agent solution obtained above was used to soak and pretreat the graphite. The graphite was natural flake graphite with a particle size of 50 mesh; the volume ratio of the intercalation agent solution to the graphite was 1:5. The graphite was soaked in the intercalation agent solution, and after soaking for 6 h, it was sealed and stored for 12 h. At the same time, stirring was carried out at a stirring speed of 20 revolutions per minute. After stirring was completed, graphite A solution was obtained. The graphite A solution above was filtered and air-dried to obtain intercalation-modified graphite B. The solid content of the intercalation-modified graphite B was 65%.

[0149] 2. Preparation of fluffy graphene:

[0150] The intercalation-modified graphite B above was pushed to the microwave feeding port through an automatic feeding machine (loss weight feeder). The gas feeding module was connected to the air inlet of the material flow bin, and the graphite B was sprayed into the microwave irradiation zone through gas feeding. The graphite B stayed in the microwave irradiation zone for 10 s and then left, wherein the gas source was air with a pressure of 0.05 MPa. The gas flow rate in the tube was 150 L / min; the power of the above microwave equipment was 15 kW. The feeding speed of the graphite B was 50 g / min. The reaction temperature of the above microwave equipment was 300°C.

[0151] The volume of the graphene was measured by a measuring cylinder, and the expansion ratio of the graphene product obtained in step (2) compared with the raw material graphite was calculated to be 98 times.

[0152] The number of layers of the graphene product was measured by a transmission electron microscope to be 3-5 layers, as shown in Figure 16 , 17 .

[0153] The characterization by Raman spectroscopy is shown in Figure 15 , and the number of layers of the graphene product is also verified to be 3-5 layers by Raman fitting results.

[0154] The ratio of the D peak to the G peak intensity (I D / I G ) of the graphene was 0.011 by Raman spectroscopy characterization.

[0155] 3. Preparation of powdered graphene

[0156] The graphene is prepared into a powder by mechanical shearing treatment. The mechanical shearing treatment is performed using an air flow pulverizer. After the mechanical shearing treatment, the number of layers of the graphene remains substantially unchanged, and no defects are formed (as shown in FIG. 1C). Figure 14 The I D / I G is 0.012.

[0157] The above merely describes several embodiments of the present application, and does not limit the present application in any form. Although the present application is disclosed with reference to the preferred embodiments, the present application is not limited to the above. Any person skilled in the art, without departing from the scope of the present application, can make some changes or modifications to the above disclosed technical contents, which are equivalent to the equivalent embodiments, and all of them belong to the scope of the technical solutions.

Claims

1. A process device for preparing graphene, characterized in that, the process device comprises a microwave unit; the microwave unit comprises a feeding section, a microwave section and a discharging section which are sequentially and horizontally connected; the feeding section comprises a microwave suppression tube I arranged horizontally, a fixed end of the microwave suppression tube I is connected with the microwave section, and an air inlet pipe is arranged in the microwave suppression tube I; the feeding section further comprises a feeding pipe, the feeding pipe is connected with the air inlet pipe, and a feeding port I of the feeding pipe is located above the microwave suppression tube I; the air inlet pipe is provided with an air inlet and an air outlet; the microwave section is provided with a microwave cavity, a microwave irradiation area is arranged in the microwave cavity; an expansion pipe is arranged in the microwave cavity, and the air outlet is connected with the expansion pipe; the discharging section comprises a microwave suppression tube II arranged horizontally, a fixed end of the microwave suppression tube II is connected with the microwave section, an outlet pipe is arranged in the microwave suppression tube II, a feeding port II of the outlet pipe is connected with the expansion pipe, and a discharging port is arranged at a free end of the outlet pipe. 2.The process device according to claim 1, characterized in that, taking the microwave cavity as a horizontal line and the air inlet as an initial point, the inclination angles of the air inlet pipe, the feeding pipe and the outlet pipe satisfy the following conditions in a clockwise direction: the inclination angle of the air inlet pipe is 0°-90° or 270°-360°; the inclination angle of the feeding pipe is 45°-90°; the inclination angle of the outlet pipe is 120°-240°. 3.The process device according to claim 1, characterized in that, the process device further comprises a pneumatic conveying module, and the pneumatic conveying module is connected with the air inlet; preferably, in the process device, The pipeline cross-sectional area of the intake pipe is 0.5-3 cm 2 ; The pipe cross-sectional area of the feed pipe is 0.5-3 cm 2 ; The pipe of the expansion pipe has a pipe cross-sectional area of 1-30 cm 2 ; The pipe cross-sectional area of the discharge pipe is 1-30 cm 2 . 4.The process device according to claim 1, characterized in that, the process device further comprises an automatic feeding machine, and the automatic feeding machine is connected with the feeding port I; the automatic feeding machine is a feeding device composed of at least one of a vibrating feeder, a gravimetric feeder, a volumetric auger-type feeder, a syringe, a compressed air-assisted feeder, a vacuum-assisted feeder, a gravity feeder, a drum feeder, a wheel feeder, a slide rail, a chute and a conveyor-type feeder. 5.The process device according to claim 1, characterized in that, the microwave section is provided with a microwave cavity in the shape of a cuboid; a microwave window is arranged on an upper surface of the microwave cavity; the microwave section is further provided with a waveguide pipe, the waveguide pipe is provided with a microwave inlet and a microwave outlet, and the microwave outlet is connected with the microwave window; preferably, the microwave section is further provided with a microwave generator, and the microwave inlet is connected with the microwave generator; preferably, the microwave section is further provided with an infrared temperature measurement module for monitoring the temperature in the microwave irradiation area; preferably, a waste gas outlet is further arranged on a cavity wall near a side of the microwave section close to the discharging port. 6.A process method for preparing graphene, characterized in that, the process method uses the process device according to any one of claims 1-5; the process method comprises: (1) pretreatment: immersing graphite I in an intercalation agent solution containing an intercalation agent, sealing and storing, and drying to obtain intercalation-modified graphite II; (2) pushing the graphite II obtained in step (1) to the feeding port I, and sending the graphite II into the microwave irradiation area in the microwave band by the gas entering through the gas inlet, so that a physical reaction occurs to obtain graphene.

7. The process method according to claim 6, characterized in that, In step (1), the intercalation agent solution comprises a polar solvent; the polar solvent is selected from 1-4 kinds of water, methanol, ethanol, propanol, ethylene glycol, and glycerol; wherein the volume ratio of each component is 0-1:0-1:0-1:0-1; Preferably, the intercalation agent is at least one of bromine, chlorine, and iodine; Preferably, the volume ratio of the intercalation agent to the polar solvent is 1-100:1-100; Preferably, the volume ratio of the intercalation agent solution to the graphite I is 1:10-10:1; Preferably, the graphite I is selected from at least one of artificial graphite and natural graphite; Preferably, the storage time is 12-120 hours; Preferably, the soaking time is 6-336 hours.

8. The process method according to claim 6, characterized in that, In step (1), the solid content of the intercalation-modified graphite II is 50-80%; Preferably, the solid content of the intercalation-modified graphite II is 60-80%.

9. The process method according to claim 6, characterized in that, In step (2), the feeding speed of the graphite II is 0.1-100 g / min; Preferably, the feeding speed of the graphite II is 35-40 g / min; Preferably, the pressure of the gas is 0.01-0.25 MPa; the flow rate of the gas is 100-200 L / min; Preferably, the microwave power in the microwave band is 1-300 kW; Preferably, the microwave power in the microwave band is 6-10 kW; Preferably, the reaction temperature is 200-500℃; Preferably, the residence time of the graphite II in the microwave irradiation area is 2-12 s.

10. The process method according to claim 6, characterized in that, the expansion ratio of the graphene is ≥80 times; Preferably, the expansion ratio of the graphene is ≥100 times; Preferably, the number of layers of the graphene is ≤5 layers; Preferably, the number of layers of the graphene is ≤3 layers; Preferably, the graphene has a ratio of the intensity of the D peak to the intensity of the G peak I D / I G ≤ 0.2; Preferably, the graphene has an I D / I G ≤ 0.05.

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