A graphene purification device

Abstract

The application discloses a graphene purification device and belongs to the technical field of graphene purification. The device comprises a feeding device, an airflow generating device, an airflow pulverizer, an airflow beam splitting device, a first-stage grading wheel, a second-stage grading wheel and a first material collecting device. The airflow beam splitter is arranged below the first-stage grading wheel. The airflow beam splitter is used for splitting the graphene powder in a fluidized state and buffering the graphene powder airflow, thereby improving the fluidized state of the graphene powder and improving the grading effect of the first-stage grading wheel. Meanwhile, the second-stage grading wheel is used for further grading the graphene powder after the first-stage grading. The second-stage grading wheel is arranged above the first-stage grading wheel, so that the powder failing to reach the target size can fall into the pulverizer again and be subjected to secondary pulverization, thereby improving the purification effect of the graphene powder.

Description

Technical Field

[0001] This application relates to the field of graphene purification technology, and in particular to a graphene purification apparatus. Background Technology

[0002] Since the discovery of graphene via micromechanical exfoliation in 2004, various preparation methods have emerged. One commonly used method is chemical vapor deposition (CVD), which produces graphene with advantages such as high product quality, large growth area, and controllable layer count, but its yield is limited and its cost is high. In 2009, a technique for preparing graphene using a molten solvent was proposed. This is a CVD-like method, but because it uses a metal as a catalyst, the resulting graphene powder inevitably contains metal impurities, necessitating the separation of these impurities.

[0003] After graphene is prepared, it is typically pulverized using a sample pulverizer and then classified by a classifying wheel to obtain samples of the target size, achieving purification. However, with traditional sample pulverizers, the graphene powder prepared by molten solvent has high strength, making it difficult for general sample pulverizers to achieve the desired crushing effect, thus affecting the purification efficiency. Furthermore, the graphene powder directly enters the classifying wheel with the airflow, reducing the classifying effect and further impacting the purification. Therefore, how to effectively separate metal powders and improve the purification efficiency of graphene powder is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this application is to provide a graphene purification device that can effectively separate metal powders and improve the purification effect of graphene powders.

[0005] To achieve the above objectives, this application provides a graphene purification apparatus, comprising: a feeding device, an airflow generating device, an airflow pulverizer, an airflow splitting device, a primary classifying wheel, a secondary classifying wheel, and a first collecting device;

[0006] The feeding device is connected to the airflow pulverizer; the airflow generating device is connected to the airflow pulverizer; the airflow pulverizer is used to separate the metal powder and the initial graphene powder in the pulverized graphene sample;

[0007] The airflow splitting device is located below the primary classifier wheel and is used to split the initial graphene powder in a fluidized state into bundles.

[0008] The primary classifying wheel is used to separate the primary graphene powder that has reached the primary size from the initial graphene powder, so that the primary graphene powder enters the secondary classifying wheel, and the initial graphene powder that has not reached the primary size falls into the air jet pulverizer.

[0009] The secondary classifying wheel, located above the primary classifying wheel, is used to separate the target graphene powder that has reached the target size from the primary graphene powder, allowing the target graphene powder to enter the first receiving device, and allowing the primary graphene powder that has not reached the target size to fall into the airflow pulverizer; the target size is smaller than the primary size.

[0010] Optionally, the airflow generating device is a compressor;

[0011] The nozzle on the compressor is disposed on the side wall of the air jet mill, and is used to introduce the compressed gas into the air jet mill, so that the graphene sample in the air jet mill is in a fluidized state.

[0012] Optionally, the number of nozzles is even and they are arranged symmetrically.

[0013] Optionally, the feeding device is connected to the air jet mill at a location below the nozzle and close to the bottom of the air jet mill.

[0014] Optionally, the first-level graded wheels are placed vertically; the second-level graded wheels are placed horizontally.

[0015] Optionally, the secondary grading wheel is located directly above the primary grading wheel.

[0016] Optionally, the graphene purification device further includes: a three-stage classifier wheel;

[0017] The secondary classifying wheel is used to separate the secondary graphene powder that has reached the secondary size from the primary graphene powder, allowing the secondary graphene powder to enter the tertiary classifying wheel, and allowing the primary graphene powder that has not reached the secondary size to fall into the air jet mill; the secondary size is smaller than the primary size.

[0018] The three-stage classifying wheel is used to separate the target graphene powder that has reached the target size from the secondary graphene powder, so that the target graphene powder enters the first receiving device; the target size is smaller than the secondary size.

[0019] The first receiving device is used to collect the target graphene powder separated by the three-stage classifier wheel.

[0020] Optionally, the graphene purification device further includes: a negative pressure fan;

[0021] The negative pressure fan is connected to the first receiving device and is used to transport the target graphene powder to the first receiving device, and to transport the graphene sample to the airflow pulverizer under negative pressure conditions.

[0022] Optionally, the graphene purification apparatus further includes: a second receiving device;

[0023] The second receiving device is used to collect the separated metal powder.

[0024] Optionally, the airflow splitting device is a screen;

[0025] The sieve, located below the primary classifying wheel, is used to allow the initial graphene powder in a fluidized state to pass through the mesh and both sides of the sieve into the primary classifying wheel.

[0026] Obviously, this application includes an airflow splitter below the primary classifier wheel. This splitter separates the fluidized graphene powder, buffers the airflow, and improves the fluidization state of the graphene powder, thus enhancing the classification effect of the primary classifier wheel. Simultaneously, a secondary classifier wheel further classifies the graphene powder after the primary classification. Located above the primary classifier wheel, the secondary classifier wheel allows powder that has not reached the target size to fall back into the pulverizer for secondary pulverization, thereby improving the purification effect of the graphene powder. Since the mass of the metal powder in the fluidized graphene powder is greater than the weight of the graphene powder, the metal powder can be effectively separated. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of a graphene purification device provided in an embodiment of this application.

[0029] Appendix Figure 1 The reference numerals in the attached figures are explained as follows:

[0030] 1-Feeding device; 2-T-way valve; 3-Airflow pulverizer; 4-Compressor; 5-Nozzle; 6-First-stage cyclone separator; 71-First-stage classifier; 72-Second-stage classifier; 73-Third-stage classifier; 81-First valve; 82-Second valve; 83-Third valve; 91-First hopper; 92-Second hopper; 93-Third hopper; 10-Second-stage cyclone separator; 11-Dust collector; 12-Negative pressure fan; 13-Screen. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a graphene purification device provided in an embodiment of this application. The graphene purification device may include: a feeding device 1, an airflow generating device, an airflow pulverizer 3, an airflow beam splitter, a primary classifier 71, a secondary classifier 72, and a first receiving device.

[0033] The feeding device 1 is connected to the air jet mill 3; the airflow generating device is connected to the air jet mill 3; the air jet mill 3 is used to separate the metal powder and the initial graphene powder in the pulverized graphene sample;

[0034] An airflow splitting device, located below the primary classifier 71, is used to split the initial graphene powder in a fluidized state into bundles.

[0035] The primary classifier wheel 71 is used to separate the primary graphene powder that has reached the primary size from the initial graphene powder, so that the primary graphene powder enters the secondary classifier wheel 72, and the initial graphene powder that has not reached the primary size falls into the air jet mill 3.

[0036] The secondary classifier 72, located above the primary classifier 71, is used to separate the target graphene powder that has reached the target size from the primary graphene powder, allowing the target graphene powder to enter the first receiving device, and allowing the primary graphene powder that has not reached the target size to fall into the air jet mill 3; the target size is smaller than the primary size.

[0037] This embodiment does not limit the specific type of feeding device 1, as long as it can deliver the graphene sample to the air jet mill 3.

[0038] This embodiment does not limit the specific type of airflow generating device, as long as it ensures that the graphene sample in the airflow pulverizer 3 is in a fluidized state. For example, the airflow generating device can be a compressor 4; the nozzle 5 on the compressor 4 is set on the side wall of the airflow pulverizer 3 to introduce compressed gas into the airflow pulverizer, so that the graphene sample in the airflow pulverizer 3 is in a fluidized state. It should be noted that this embodiment uses compressed gas to disperse the graphene powder, and the graphene powder is pulverized through the collision between the graphene powder particles.

[0039] Furthermore, to increase the collision probability of the graphene sample in the air jet mill 3, the number of nozzles 5 in this embodiment can be even and symmetrically arranged. This embodiment does not limit the specific number of nozzles 5; the specific number of nozzles 5 can be determined according to actual conditions. For example, the number of nozzles 5 can be 2 to 10, including the values ​​at both ends. This embodiment does not limit the specific diameter of the nozzles 5; the specific diameter of the nozzles 5 can be determined according to actual conditions. For example, the diameter of the nozzles 5 can be 1 mm to 4 mm, including the values ​​at both ends. This embodiment does not limit the specific position of the nozzles 5; the specific position of the nozzles 5 can be determined according to actual conditions. For example, the distance from the nozzle 5 to the first-stage classifier 71 can be 0.3 m to 2 m, including the values ​​at both ends.

[0040] Furthermore, the purification effect of graphene powder and metal powder can be adjusted by changing the pressure of nozzle 5. Therefore, in this embodiment, the pressure of nozzle 5 can be 0.2MPa to 2MPa, including the values ​​at both ends.

[0041] Furthermore, to increase the collision probability of the graphene sample in the air jet mill 3, in this embodiment, the connection position between the feeding device 1 and the air jet mill 3 can be located below the nozzle 5 and close to the bottom of the air jet mill 3. It should be noted that in this embodiment, the collision probability of the graphene sample in the chamber of the air jet mill 3 is much higher than that of a traditional air jet mill, achieving a 100% material collision and dispersal rate.

[0042] It should be noted that in this embodiment, the number of nozzles 5 is even and they are symmetrically arranged; the connection position between the feeding device 1 and the air jet mill 3 can be located below the nozzles 5 and close to the bottom of the air jet mill 3, which can improve the collision probability of the graphene sample in the air jet mill 3 and improve the pulverization effect of the graphene sample, thereby improving the purification effect of graphene powder and metal powder; at the same time, the purification effect of graphene powder and metal powder can be adjusted by adjusting the pressure of the nozzles 5, the number of nozzles 5, the diameter of the nozzles 5, and the distance from the nozzles 5 to the first-stage classifier 71.

[0043] This embodiment does not limit the specific type of airflow splitting device, as long as it can split the initial graphene powder in the fluidized state. For example, the airflow splitting device can be a screen 13. The screen 13 is located below the primary classifier 71 and is used to allow the initial graphene powder in the fluidized state to enter the primary classifier 71 through the mesh and both sides of the screen 13.

[0044] Furthermore, in order to improve the purification effect of graphene powder, in this embodiment, the primary classifying wheel 71 can be placed vertically; the secondary classifying wheel 72 can be placed horizontally.

[0045] Furthermore, in order to make it easier for primary graphene powder that has not reached the target size to fall into the air jet mill 3, in this embodiment, the secondary classifying wheel 72 can be located directly above the primary classifying wheel 71.

[0046] Furthermore, to improve the purification effect of graphene powder, this embodiment may further include: a three-stage classifying wheel 73; a two-stage classifying wheel 72, used to separate secondary graphene powder that reaches the secondary size from the primary graphene powder, allowing the secondary graphene powder to enter the three-stage classifying wheel 73, and allowing primary graphene powder that does not reach the secondary size to fall into the air jet mill 3; the secondary size is smaller than the primary size; the three-stage classifying wheel 73, used to separate the target graphene powder that reaches the target size from the secondary graphene powder, allowing the target graphene powder to enter the first collecting device; the target size is smaller than the secondary size; the first collecting device is used to collect the target graphene powder separated by the three-stage classifying wheel 73. It should be noted that by using the three-stage classifying wheel 73 to classify graphene powder, different grades of graphene powder can be obtained.

[0047] This embodiment does not limit the specific model of the primary classifying wheel 71, as long as it can separate primary graphene powder. This embodiment does not limit the specific model of the secondary classifying wheel 72, as long as it can separate secondary graphene powder. This embodiment does not limit the specific model of the tertiary classifying wheel 73, as long as it can separate the target graphene powder. This embodiment does not limit the specific number of blades in the primary, secondary, and tertiary classifying wheels 71, 72, and 73, as long as the number of blades increases sequentially and the linear velocity increases sequentially. For example, in this embodiment, the number of blades in the primary classifying wheel 71 is 20 to 60, including the values ​​at both ends; the number of blades in the secondary classifying wheel 72 is 60 to 100, including the values ​​at both ends; and the number of blades in the tertiary classifying wheel 73 is 100 to 200, including the values ​​at both ends. This embodiment does not limit the specific type of the secondary classifying wheel 72, as long as it has the function of separating the primary graphene powder. For example, the secondary classifying wheel 72 can be a classifying wheel in a cyclone separator. This embodiment does not limit the specific type of the tertiary classifying wheel 73, as long as it has the function of separating the target graphene powder. For example, the tertiary classifying wheel 73 can be a classifying wheel in a cyclone separator.

[0048] Furthermore, to prevent oxidation and explosion of the metal powder during transportation, this embodiment may also include: a negative pressure fan 12; the negative pressure fan 12 is connected to the first receiving device, used to transport the target graphene powder to the first receiving device, and to transport the graphene sample to the airflow pulverizer 3 under negative pressure conditions by the feeding device 1. This embodiment does not limit the specific pressure of the negative pressure fan 12; for example, the pressure of the negative pressure fan 12 can be -0.05MPa to -0.001MPa, including both values.

[0049] Furthermore, in this embodiment, the first output end of the negative pressure fan 12 can be connected to the first receiving device; the second output end of the negative pressure fan 12 is connected to the first opening of the tee 2; the feeding device 1 is connected to the second opening of the tee 2; and the airflow pulverizer 3 is connected to the third opening of the tee 2. It should be noted that the feeding device 1, the airflow pulverizer 3, and the negative pressure fan 12 are connected through the tee 2, making the entire device sealed and allowing gas circulation inside the device.

[0050] Furthermore, to recover the metal powder, this embodiment may also include: a second collecting device; the second collecting device is used to collect the separated metal powder. Furthermore, to recover the secondary graphene powder, this embodiment may also include: a third collecting device; the second collecting device is used to collect the separated secondary graphene powder.

[0051] This embodiment does not limit the specific type of the first collecting device, as long as it can collect the target graphene powder; for example, it can be a material bucket. This embodiment does not limit the specific type of the second collecting device, as long as it can collect metal powder; for example, it can be a material bucket. This embodiment does not limit the specific type of the second collecting device, as long as it can collect secondary graphene powder; for example, it can be a material bucket. Furthermore, to control the timing or amount of metal powder and graphene powder collection, this embodiment may also include: a first valve 81, a second valve 82, and a third valve 83; the first valve 81 is connected to the third collecting device; the second valve 82 is connected to the second collecting device; and the third valve 83 is connected to the first collecting device. Furthermore, to remove dust from the separated target graphene powder, this embodiment may also include: a dust collector 11; the first input end of the dust collector 11 is connected to the three-stage classifier 73, the second input end is connected to the negative pressure fan 12, and the output end is located above the first collecting device.

[0052] Based on the above embodiments, this application provides an airflow splitter below the primary classifier 71. The airflow splitter separates the graphene powder in a fluidized state, buffers the airflow, improves the fluidization state of the graphene powder, and enhances the classification effect of the primary classifier 71. Simultaneously, a secondary classifier 72 further classifies the graphene powder after classification by the primary classifier 71. Since the secondary classifier 72 is located above the primary classifier 71, powder that has not reached the target size can fall back into the pulverizer for secondary pulverization, thereby improving the purification effect of the graphene powder. Because the mass of the metal powder in the fluidized graphene powder is greater than the weight of the graphene powder, the metal powder can be effectively separated.

[0053] The graphene purification process is illustrated below with specific examples. Please refer to them. Figure 1 , Figure 1This is a schematic diagram of a graphene purification device provided in an embodiment of this application. The graphene purification device includes: a feeding device 1, a three-way valve 2, an air jet mill 3, a compressor 4, a nozzle 5, a primary cyclone separator 6, a primary classifier wheel 71, a secondary classifier wheel 72, a tertiary classifier wheel 73, a first valve 81, a second valve 82, a third valve 83, a first material container 91, a second material container 92, a third material container 93, a secondary cyclone separator 10, a dust collector 11, a negative pressure fan 12, and a screen 13. The three-way valve 2 connects the feeding device 1, the air jet mill 3, and the negative pressure fan 12. The connection between the feeding device 1 and the air jet mill 3 is located below the nozzle 5. The primary classifier wheel 71 is placed vertically, while the secondary classifier wheel 72 and the tertiary classifier wheel 73 are placed horizontally. The secondary classifier wheel 72 is located directly above the primary classifier wheel 71. The first valve 81, the second valve 82, and the third valve 83 are respectively connected to the first material barrel 91, the second material barrel 92, and the third material barrel 93.

[0054] The purification process using the aforementioned graphene purification device includes: loading the graphene sample into the feeding device 1, and using a negative pressure fan 12 to feed and transport the powder under negative pressure conditions. The gas is compressed by the compressor 4, and then the airflow through the nozzle 5 drives the graphene powder to collide and pulverize it. The heavier metal powder in the pulverized powder first settles in the first feed cylinder. A screen 13 is located below the primary classifier 71, and lighter graphene powder enters the primary classifier 71 through the mesh or sides of the screen 13. The screen 13 buffers the airflow of the graphene powder, improving the fluidization state of the graphene powder. Simultaneously, the graphene powder pulverized by the primary classifier 71 passes through the secondary classifier 72 in the primary cyclone separator 6. The secondary classifier 72 is located directly above the primary classifier 71. Larger graphene powders, unable to pass through the primary cyclone separator 6, fall into the air jet mill 3 after passing through the primary classifier 71 and are further pulverized into smaller sizes. The powder passing through the primary cyclone separator 6 enters the secondary cyclone separator 10 for further separation. Larger particles fall into the second feed hopper 92, while smaller graphene powders pass through the dust collector 11 into the third feed hopper 93, thus classifying the graphene powder. A primary classifying wheel 71 and two-stage cyclone separators are used for graphene powder classification. Using the above-mentioned graphene purification device, different grades of graphene powder and metal powder can be obtained. The performance and added value of the products can be significantly improved, making it suitable for graphene powder classification and purification technology and product upgrade applications.

[0055] Example 1

[0056] Step 1. Set the pressure of nozzle 5 to 10MPa, the diameter of nozzle 5 to 4mm, and the distance from nozzle 5 to the first-stage classifier wheel 71 to 0.8m.

[0057] Step 2. Close the first valve 81, the second valve 82 and the third valve 83, adjust the pressure of the negative pressure fan 12 to -0.01MPa, and add the crude graphene to this device through the feeding device.

[0058] Step 3. After running for a period of time, open the first valve 81, the second valve 82 and the third valve 83 to obtain copper powder in the first material tank 91, graphene powder 1 in the second material tank 92 and graphene powder 2 in the second material tank 92.

[0059] Example 2

[0060] Step 1. Set the pressure of nozzle 5 to 15MPa, the diameter of nozzle 5 to 4mm, and the distance from nozzle 5 to the first-stage classifier wheel 71 to 0.8m.

[0061] Step 2. Close the first valve 81, the second valve 82 and the third valve 83, adjust the pressure of the negative pressure fan 12 to -0.01MPa, and add the crude graphene to this device through the feeding device.

[0062] Step 3. After running for a period of time, open the first valve 81, the second valve 82 and the third valve 83 to obtain copper powder in the first material tank 91, graphene powder 1 in the second material tank 92 and graphene powder 2 in the second material tank 92.

[0063] Example 3

[0064] Step 1. Set the pressure of nozzle 5 to 15MPa, the diameter of nozzle 5 to 2mm, and the distance from nozzle 5 to the first-stage classifier wheel 71 to 0.8m.

[0065] Step 2. Close the first valve 81, the second valve 82 and the third valve 83, adjust the pressure of the negative pressure fan 12 to -0.01MPa, and add the crude graphene to this device through the feeding device.

[0066] Step 3. After running for a period of time, open the first valve 81, the second valve 82 and the third valve 83 to obtain copper powder in the first material tank 91, graphene powder 1 in the second material tank 92 and graphene powder 2 in the second material tank 92.

[0067] Example 4

[0068] Step 1. Set the pressure of nozzle 5 to 15MPa, the diameter of nozzle 5 to 5mm, and the distance from nozzle 5 to the first-stage classifier wheel 71 to 0.5m.

[0069] Step 2. Close the first valve 81, the second valve 82 and the third valve 83, adjust the pressure of the negative pressure fan 12 to -0.01MPa, and add the crude graphene to this device through the feeding device.

[0070] Step 3. After running for a period of time, open the first valve 81, the second valve 82 and the third valve 83 to obtain copper powder in the first material tank 91, graphene powder 1 in the second material tank 92 and graphene powder 2 in the second material tank 92.

[0071] Example 5

[0072] Step 1. Set the pressure of nozzle 5 to 15MPa, the diameter of nozzle 5 to 2mm, and the distance from nozzle 5 to the first-stage classifier wheel 71 to 0.8m.

[0073] Step 2. Close the first valve 81, the second valve 82 and the third valve 83, adjust the pressure of the negative pressure fan 12 to -0.05MPa, and add the crude graphene product to this device through the feeding device.

[0074] Step 3. After running for a period of time, open the first valve 81, the second valve 82 and the third valve 83 to obtain copper powder in the first material tank 91, graphene powder 1 in the second material tank 92 and graphene powder 2 in the second material tank 92.

[0075] The above five embodiments obtained copper powder and graphene powder with different purities and particle sizes by setting different negative pressure, nozzle 5 pressure, nozzle 5 diameter and distance from nozzle 5 to primary classifier 71, as detailed in Table 1.

[0076] Table 1 shows the specific parameters of the apparatus and the specific parameters of the purified copper powder and graphene powder obtained in the five embodiments.

[0077]

[0078] This document uses specific examples to illustrate the principles and implementation methods of this application. The various embodiments are progressive, with each embodiment focusing on its differences from others. Similar or identical parts between embodiments can be referred to interchangeably. The descriptions of the embodiments above are merely illustrative of the method and core ideas of this application. For those skilled in the art, various improvements and modifications can be made to this application without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this application.

[0079] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

Claims

1. A graphene purification apparatus, characterized by, The application relates to a graphene sample processing device. The device comprises a feeding device, an airflow generating device, an airflow pulverizer, an airflow splitting device, a first-stage grading wheel, a second-stage grading wheel and a first collecting device. The airflow generating device is a compressor; nozzles on the compressor are arranged on the side wall of the airflow pulverizer, the number of the nozzles is even, and the nozzles are symmetrically arranged, so that compressed air is introduced into the airflow pulverizer, and the graphene sample in the airflow pulverizer is in a fluidized state. The connecting position of the feeding device and the airflow pulverizer is below the nozzles and close to the bottom of the airflow pulverizer, so that the graphene sample is delivered to the airflow pulverizer. The airflow pulverizer is used for dispersing graphene powder with metal impurities by using the compressed air, and the graphene powder is pulverized through collision between the graphene powder; the metal powder and the initial graphene powder in the pulverized graphene sample are separated, and the metal powder is deposited in a first cylinder. The airflow splitting device is a screen; the screen is arranged below the first-stage grading wheel and is used for splitting the initial graphene powder in a fluidized state, so that the initial graphene powder in the fluidized state passes through the mesh holes of the screen and the two sides and enters the first-stage grading wheel. The first-stage grading wheel is vertically arranged and is used for separating the first-stage graphene powder reaching a first-stage size from the initial graphene powder, so that the first-stage graphene powder enters the second-stage grading wheel, and the initial graphene powder not reaching the first-stage size falls into the airflow pulverizer. The second-stage grading wheel is horizontally arranged above the first-stage grading wheel and is used for separating the target graphene powder reaching a target size from the first-stage graphene powder, so that the target graphene powder enters the first collecting device, and the first-stage graphene powder not reaching the target size falls into the airflow pulverizer; the target size is smaller than the first-stage size.

2. The graphene purification apparatus of claim 1, wherein, The second-stage grading wheel is arranged directly above the first-stage grading wheel.

3. The graphene purification apparatus of claim 1, wherein, Further, the application also relates to a graphene sample processing device. The device comprises a third-stage grading wheel. The second-stage grading wheel is used for separating the second-stage graphene powder reaching a second-stage size from the first-stage graphene powder, so that the second-stage graphene powder enters the third-stage grading wheel, and the first-stage graphene powder not reaching the second-stage size falls into the airflow pulverizer. The second-stage size is smaller than the first-stage size. The third-stage grading wheel is used for separating the target graphene powder reaching the target size from the second-stage graphene powder, so that the target graphene powder enters the first collecting device. The target size is smaller than the second-stage size. The first collecting device is used for collecting the target graphene powder separated by the third-stage grading wheel.

4. The graphene purification apparatus of claim 1, wherein, Further, the application also relates to a graphene sample processing device. The device comprises a negative pressure fan. The negative pressure fan is connected with the first collecting device and is used for delivering the target graphene powder to the first collecting device, and the feeding device is used for delivering the graphene sample to the airflow pulverizer under negative pressure.

5. The graphene purification apparatus of claim 1, wherein, Further, the application also relates to a graphene sample processing device. The device comprises a second collecting device. The second collecting device is used for collecting the separated metal powder.

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