A preparation method of graphene powder material

Abstract

The present invention discloses a preparation method of graphene powder materials, specifically related to the technical field of powder material mixing, which includes putting graphene powder into the main feeding hopper, putting auxiliary powder into the secondary feeding hopper, controlling the continuous movement of the attachment belt, so that the graphene powder layer and the auxiliary powder layer stacked above it are conveyed backward together until they are conveyed to the blanking area, starting the stirring component to perform secondary stirring and mixing on the powder materials that have been premixed in the stirring bin, closing the stirring component, and taking out the mixed powder materials. With the restriction of the output gap of the main extension pipe and the output gap of the secondary extension pipe, the present invention enables the auxiliary powder to be evenly laid on the pre-formed graphene powder layer, thereby realizing the pre-uniform distribution of different powder materials, effectively preventing the agglomeration of graphene powder, and thus effectively improving the bonding uniformity between the graphene powder and the auxiliary powder.

Description

Technical Field

[0001] The present invention relates to the technical field of powder material mixing, and more specifically, to a method for preparing graphene powder materials. Background Art

[0002] Graphene is a new material with a single-layer two-dimensional honeycomb lattice structure formed by closely packing carbon atoms hybridized by sp². Graphene has excellent optical, electrical, and mechanical properties, and has important application prospects in materials science, micro-nano processing, energy, biomedicine, and drug delivery, and is considered a revolutionary material for the future.

[0003] Essentially, graphene is a two-dimensional material composed of a single layer of carbon atoms. However, in practical applications, for the convenience of storage, transportation, and processing, graphene is mainly prepared in powder form. Moreover, in order to improve and fully utilize the excellent properties of graphene (such as electrical conductivity, thermal conductivity, mechanical reinforcement, etc.) and uniformly disperse it into the target material, it is necessary to pre-mix the graphene powder material with other related raw materials (in powder form), such as catalysts, conductive agents, initiators, and other materials.

[0004] Among them, the mixing of the above powder materials is mainly carried out using a stirring mixer, and each material is simultaneously put into the stirring mixer (or gradually put in from a hopper) according to the material ratio in advance. For the production of a large amount of graphene powder materials, in order to improve production efficiency, a stirring mixer with a larger capacity will be used, and a large amount of powder materials will be put in at one time to accelerate the mixing speed.

[0005] However, when the graphene powder material is put in, when it directly enters the inner cavity of the mixer, the space in the inner cavity of the mixer is relatively large, and the amount of graphene powder material put in at one time is relatively large. The graphene powder material has enough space to converge and is difficult to disperse for a while.

[0006] In particular, there are still strong van der Waals forces and electrostatic forces in graphene powder in the dry state, which causes the sheets to easily attract and stack with each other, resulting in the agglomeration of graphene powder. As a result, the graphene powder materials fed each time will form agglomerated materials of different sizes. Moreover, the more graphene powder materials are fed at one time and the larger the space of the mixer they are fed into, the more agglomeration phenomena will occur, making it difficult to mix fully with other materials. Even with the action of the stirrer in the mixer, most of the larger agglomerated powder materials can be broken up, but there will still be many smaller micro-agglomerated graphene powder materials. Due to the adsorption of graphene powder on other materials, many tiny "balls" of other materials wrapping the agglomerated graphene powder materials will be formed, resulting in insufficient and uneven mixing, which greatly affects the performance of the final graphene material (for example, when making electrode materials, binders, catalysts, and conductive agents need to be added. If graphene cannot be evenly mixed with the raw materials, it will greatly affect the balance of the electrode, increase the internal resistance, and reduce the electrode performance). Summary of the Invention

[0007] A preparation method of graphene powder materials provided by the present invention aims to solve the following problem: in the existing mixing scheme, when the graphene powder materials are fed, the inner cavity space of the mixer is relatively large, and the graphene powder materials have enough space to converge, resulting in more agglomeration phenomena of graphene powder, which in turn affects the mixing effect of different materials.

[0008] To achieve the above object, the present invention provides the following technical solution: A preparation method of graphene powder materials uses a secondary mixing device to mix graphene powder and auxiliary powder, including the following steps:

[0009] Step 1: Put graphene powder into the main feeding hopper, make the powder materials in the main feeding hopper contact the attachment belt through the main extension pipe, and then drive the attachment belt to move. Through the output gap of the main extension pipe, the excess graphene powder is blocked in the main extension pipe, and the graphene powder layer attached to the attachment belt is output.

[0010] Step 2: After the graphene powder layer reaches the bottom of the secondary extension pipe, put the auxiliary powder into the secondary feeding hopper, make the auxiliary powder in the secondary feeding hopper contact the graphene powder layer already formed on the attachment belt through the secondary extension pipe, and continuously drive the attachment belt to convey. Through the output gap of the secondary extension pipe, the excess auxiliary powder is blocked in the secondary extension pipe, and the auxiliary powder layer attached to the graphene powder layer on the attachment belt is output.

[0011] Step 3: Control the continuous movement of the attachment belt, so that the graphene powder layer and the auxiliary powder layer stacked above it are conveyed backward together until they are conveyed to the blanking area, and the graphene powder materials and the auxiliary powder materials fall off the attachment belt.

[0012] Step 4: The powder material separated from the attachment belt falls into the mixing bin for collection. After all the materials in the main upper hopper and the auxiliary upper hopper are output, the mixing component is started to perform secondary mixing on the pre-mixed powder material in the mixing bin.

[0013] Step 5: Close the stirring assembly, open the closed door at the discharge port at the bottom of the stirring bin, and take out the mixed powder material.

[0014] In a preferred embodiment, the secondary mixing device includes a mixer and a feeder, the mixer includes a stirring bin and a pre-mixing bin, the pre-mixing bin is arranged on the stirring bin, the feeder includes a main feed hopper and an auxiliary feed hopper, the main feed hopper and the auxiliary feed hopper are both installed on the pre-mixing bin, a stirring assembly is arranged in the stirring bin, a layered mixing assembly is arranged in the pre-mixing bin, the layered mixing assembly includes an attachment belt and a belt roller, the attachment belt is a belt-type annular structure, the attachment belt is made of rubber, at least two groups of belt rollers are arranged, the belt rollers support the attachment belt to form a conveying structure, a conveying area is formed above the attachment belt, and the attachment belt conveying area A material dropping area is formed at the conveying end of the domain, and a main extension tube is arranged at the bottom of the main upper hopper, and a secondary extension tube is arranged at the bottom of the secondary upper hopper, and the bottom ports of the main extension tube and the secondary extension tube are arranged corresponding to the conveying area of ​​the attachment belt, and input gaps and output gaps are respectively formed on both sides of the main extension tube and the areas corresponding to the attachment belt on both sides of the secondary extension tube, and the input gaps and the output gaps are arranged in sequence along the conveying direction of the attachment belt, and along the conveying direction of the attachment belt, the output gaps of the main extension tube and the secondary extension tube are arranged to increase in sequence, and flat pressure guide plates are arranged at the output gaps of the main extension tube and the secondary extension tube.

[0015] In a preferred embodiment, an air nozzle is provided outside the blanking area of ​​the attachment belt, and multiple groups of air nozzles are provided. An air equalization bin is provided in the premixing bin, and the air equalization bin is connected to a fan duct, and the fan duct is connected to a fan structure. The air nozzle is used to blow air downward through the fan structure and blow it toward the arc surface at the matching point between the attachment belt and the belt roller in the blanking area to blow away the powder material on the attachment belt.

[0016] In a preferred embodiment, a cleaning brush is provided below the blanking area of ​​the attachment belt, and the bristles of the cleaning brush are in contact with the attachment belt. When the attachment belt moves, the residual powder material on the surface of the attachment belt is cleaned by the cleaning brush. A vibration seat is also provided in the premixing bin, and the vibration seat is installed in the premixing bin through an elastic member. A vibrator is fixedly installed on the vibration seat, and a vibration roller is rotatably installed on the vibration seat. The vibration roller is in contact with a position of the attachment belt away from the conveying area, and the corresponding area of ​​the attachment belt is driven to vibrate through the vibration seat to shake the residual powder material on the surface of the attachment belt downward.

[0017] In a preferred embodiment, a humidification chamber is provided in the area below the attachment belt. An atomizing nozzle is provided in the humidification chamber. When the attachment belt passes through the humidification chamber, the humidity of the surface of the attachment belt is increased by the atomizing nozzle. An air heater is installed in the air equalizing chamber, and the air before being blown out by the air nozzle is heated by the air heater. A filter type exhaust pipe is provided in the premixing chamber, and the filter type exhaust pipe is docked with the fan structure connected to the fan pipeline.

[0018] In a preferred embodiment, a wiping roller is provided at the position where the side wall of the humidification chamber cooperates with the attachment belt. The wiping roller is rotatably installed at the top of the side wall of the humidification chamber. The surface of the wiping roller is a sponge layer structure. By the rolling cooperation of the wiping roller and the attachment belt, the excess moisture on the surface of the attachment belt is scraped and absorbed.

[0019] In a preferred embodiment, in steps one and two, after adding the corresponding powder materials to the main feeding hopper and the auxiliary feeding hopper, a plurality of grinding balls are put into the main feeding hopper and the auxiliary feeding hopper. The grinding balls sink under the action of their own weight and gather at the main extension pipe and the auxiliary extension pipe. A support backing plate is provided on the inner side of the attachment belt. Through the movement of the attachment belt and the cooperation with the corresponding grinding balls, the grinding balls generate corresponding rolling and movement, forming stirring and downward extrusion of the corresponding powder materials.

[0020] In a preferred embodiment, after adding the grinding balls, a covering and pressing bag is placed in both the main feeding hopper and the auxiliary feeding hopper. The inside of the covering and pressing bag is filled with multiple groups of metal particles, and the covering and pressing bag is laid flat above the corresponding powder materials.

[0021] In a preferred embodiment, the flat pressing guide plate in the main extension pipe is slidably installed in the main extension pipe, and the flat pressing guide plate in the auxiliary extension pipe is slidably installed in the auxiliary extension pipe. And distance regulators for controlling the movement of the flat pressing guide plate are provided on both the main extension pipe and the auxiliary extension pipe. Among them, the sliding direction of the flat pressing guide plate is relatively inclined to the conveying direction of the conveying area of the attachment belt. The position of the corresponding flat pressing guide plate is controlled by the distance regulator to adjust the cross-sectional size and the output gap size of the corresponding main extension pipe or auxiliary extension pipe.

[0022] In a preferred embodiment, the attachment belt includes a base belt and a thin-walled elastic belt. The base belt is located in the inner circle. Multiple groups of filling strips are provided at the position of the base belt corresponding to the thin-walled elastic belt. The elastic coefficient of the thin-walled elastic belt is greater than that of the base belt. When the attachment belt moves to the belt roller in the blanking area, an arc area is formed, and the thin-walled elastic belt is stretched.

[0023] The beneficial effects of the present invention are as follows: By means of the output gap of the main extension tube, the excess graphene powder is blocked in the main extension tube, and a thinner layer of graphene powder attached to the attachment belt is output. Through the limitation of the output gap of the secondary extension tube, the auxiliary powder can be evenly laid on the pre-formed graphene powder layer, thereby realizing the pre-uniform distribution of different powder materials. As a result, when the powder materials leave the attachment belt, they can be directly and evenly mixed. Moreover, due to the limitation of the output gap, there is not enough space for the graphene powder to agglomerate. Therefore, the binding uniformity between the graphene powder and the auxiliary powder can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flowchart of the preparation method of the present invention.

[0025] Figure 2 It is a schematic structural diagram of the secondary mixing device used in the preparation method of the present invention.

[0026] Figure 3 It is a schematic internal structure diagram of the secondary mixing device of the present invention.

[0027] Figure 4 It is a schematic diagram of the cooperation between the main extension tube and the secondary extension tube of the present invention and the attachment belt.

[0028] Figure 5 It is a state diagram of the air nozzle of the present invention blowing air to the material dropping area at the end of the attachment belt to accelerate the separation and falling of the mixed powder.

[0029] Figure 6 It is a schematic structural diagram of the improved layered mixing component of the present invention.

[0030] Figure 7 For the present invention Figure 6 Enlarged view of the structure of part A.

[0031] Figure 8 It is a schematic structural diagram of the improved feeding component of the present invention.

[0032] Figure 9 For the present invention Figure 8 Enlarged view of the structure of part B.

[0033] Figure 10 Detailed schematic structural diagram of the attachment belt of the present invention.

[0034] Figure 11 For the present invention Figure 10 Enlarged view of the structure of part C.

[0035] The reference numerals are: 1, mixer; 11, stirring bin; 12, premixing bin; 121, air equalizing bin; 122, fan duct; 123, air heater; 124, humidifying bin; 125, filter type suction pipe; 2, feeder; 21, main feeding hopper; 211, main extension pipe; 22, auxiliary feeding hopper; 221, auxiliary extension pipe; 23, flat pressing guide plate; 24, grinding balls; 25, covering bag; 26, distance regulator; 3, layered mixing assembly; 31, attachment belt; 311, base belt; 312, filling strip; 313, thin-walled elastic belt; 32, belt roller; 33, cleaning brush; 34, supporting cushion plate; 35, vibration seat; 36, beam pressing roller; 4, stirring assembly; 41, stirring shaft; 42, stirring blades; 5, air nozzle; 6, atomizing nozzle; 7, wiping roller. Detailed implementation mode

[0036] The present application will be further described in detail below with reference to the accompanying drawings. It is necessary to point out here that the following detailed implementation modes are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application according to the above application content.

[0037] Refer to the accompanying drawings of the specification Figure 1 and 2, a method for preparing graphene powder materials. This preparation method uses a secondary mixing device to mix graphene powder and other required auxiliary powders (such as binders, catalysts, conductive agents). Among them, the secondary mixing device includes a mixer 1 and a feeder 2. The mixer 1 includes a stirring bin 11 and a pre-mixing bin 12. The pre-mixing bin 12 is arranged on the stirring bin 11. The feeder 2 includes a main hopper 21 and a secondary hopper 22. Both the main hopper 21 and the secondary hopper 22 are installed on the pre-mixing bin 12. A stirring component 4 is arranged in the stirring bin 11, and a layered mixing component 3 is arranged in the pre-mixing bin 12. The layered mixing component 3 includes an attachment belt 31 and belt rollers 32. The attachment belt 31 is a belt-shaped annular structure. At least two groups of the belt rollers 32 support the attachment belt 31 to form a conveying structure similar to a conveyor belt. At least one group of the attachment belt 31 is driven to rotate by a driving device to form a driving force for the attachment belt 31. Under the support of the attachment belt 31, a conveying area is formed above the attachment belt 31. At the conveying end along the conveying direction of the conveying area of the attachment belt 31, that is, at the position corresponding to the belt roller 32 at this position, a blanking area is formed. This blanking area corresponds to the stirring bin 11. The bottom of the main hopper 21 is provided with a main extension pipe 211, and the bottom of the secondary hopper 22 is provided with a secondary extension pipe 221. The bottom ports of the main extension pipe 211 and the secondary extension pipe 221 are both arranged corresponding to the conveying area of the attachment belt 31 and form corresponding gaps, that is, the main extension pipe 211 and the secondary extension pipe 221 do not directly contact the attachment belt 31. Input gaps and output gaps are respectively formed on both sides of the main extension pipe 211 and both sides of the secondary extension pipe 221 corresponding to the area of the attachment belt 31, and the input gaps and output gaps are arranged in sequence along the movement and conveying direction of the attachment belt 31 (that is, along the conveying direction of the conveying area corresponding to the attachment belt 31). Along the conveying direction of the attachment belt 31, the output gaps of the main extension pipe 211 and the secondary extension pipe 221 are arranged to increase in sequence (wherein, the main hopper 21 is mainly used to put graphene powder, so only one needs to be set. The secondary hopper 22 is used to put other auxiliary powders. Therefore, one can be set to put all the auxiliary powders at the same time, or multiple can be set to respectively put the corresponding auxiliary powders. So, when the number of the secondary hoppers 22 is set to multiple, the output gaps of each secondary hopper 22 also gradually increase along the output direction of the attachment belt 31). And flat pressing guide plates 23 are arranged at the output gaps of the main extension pipe 211 and the secondary extension pipe 221.

[0038] Specifically, the preparation method includes the following steps:

[0039] Step 1: Put the graphene powder into the main hopper 21, so that the powder material in the main hopper 21 contacts the attachment belt 31 through the main extension pipe 211. The attachment belt 31 is mainly made of rubber and has tiny pores on its surface. The graphene powder that directly contacts the attachment belt 31 will form an attachment layer. Then, drive the attachment belt 31 to start preliminary movement, so that the area of the attachment belt 31 initially attached with graphene powder moves backward. With the output gap of the main extension pipe 211, the excess graphene powder is blocked in the main extension pipe 211 (even if the graphene powder in the main extension pipe 211 agglomerates, but the size of the output gap is limited, and the graphene powder that can be attached to the attachment belt 31 forms a thin attachment layer). Finally, a relatively thin layer of graphene powder attached to the attachment belt 31 is output, and this layer of graphene powder layer is transported backward along with the transport of the attachment belt 31 to the secondary extension pipe 221;

[0040] Step 2: After the initially formed graphene powder layer completely reaches the bottom of the secondary extension pipe 221, put other auxiliary powders to be mixed into the secondary hopper 22 (in actual preparation, according to requirements, all auxiliary powders can be pre-mixed and put into a single secondary hopper 22 at the same time, or according to requirements, set the corresponding number of secondary hoppers 22 and put the corresponding auxiliary powders separately), so that the auxiliary powder in the secondary hopper 22 contacts the powder layer already formed on the attachment belt 31 (i.e., the initially formed graphene powder layer) through the secondary extension pipe 221, and continuously drive the attachment belt 31 to transport. At this time, since the output gap of the secondary extension pipe 221 is larger than the output gap of the previous main extension pipe 211, therefore, the auxiliary powder can be evenly spread and attached on the graphene powder layer. Due to the limitation of the output gap, there is not enough space for the graphene powder to agglomerate, so the bonding uniformity between the graphene powder and the auxiliary powder can be effectively improved;

[0041] Step 3: Control the continuous movement of the attachment belt 31, so that the graphene powder layer and the auxiliary powder layer superimposed on it are transported backward together. When transported to the blanking area, since an arc structure is formed between the attachment belt 31 and the belt roller 32 here, therefore, the powder begins to fall under the action of gravity. Since the auxiliary powder medium and the graphene powder are in a layered state of mutual superposition in the previous steps, they are also in a uniform pre-mixed state when separating from the attachment belt 31 at this time;

[0042] Step 4: The powder material separated from the attachment belt 31 falls into the mixing bin 11 for collection. After all the materials in the main hopper 21 and the secondary hopper 22 are output, drive the mixing component 4 to start running, and perform secondary stirring and mixing on the powder materials that have been pre-mixed in the mixing bin 11 to further improve the mixing uniformity;

[0043] Step 5: Turn off the stirring assembly 4, open the closing door at the bottom discharge opening of the stirring bin 11, and take out the fully mixed powder materials.

[0044] It should be noted that the flat pressing guide plate 23 is a plate-like structure with its main body parallel to the attaching belt 31. The output gap is actually the area formed between the flat pressing guide plate 23 and the attaching belt 31. Both ends of the flat pressing guide plate 23 have an upwardly curved structure. Thus, when each powder material follows the attaching belt 31 and passes through the flat pressing guide plate 23, while ensuring that the excess powder is blocked, it can also effectively extrude the corresponding powder material, ensuring that the powder materials added in different layers can be fully mixed.

[0045] Further, referring to the attached drawings of the specification Figure 3 In order to make the powder fall sufficiently in the blanking area of the attaching belt 31, the present embodiment also provides the following method. Specifically, an air nozzle 5 is provided outside the blanking area of the attaching belt 31. The air nozzle 5 is used to blow out air downward, and then the air is blown onto the arc surface at the mating part of the attaching belt 31 and the belt roller 32 in the blanking area, accelerating the detachment of each layer of powder material. And when detaching, since each layer of powder material has been uniformly laid beforehand, when it detaches from the attaching belt 31 into the air, it will be pre-installed to disperse and mix with each other according to the originally laid layers. Coupled with the blowing of the air flow, the powder materials can be more fully fused with each other, improving the mixing efficiency and ensuring that the powder materials can fully detach and fall in the blanking area.

[0046] Among them, a plurality of groups of the air nozzles 5 are provided. An air equalizing chamber 121 is provided in the pre-mixing bin 12. A blower pipeline 122 is connected to the air equalizing chamber 121. The blower pipeline 122 is connected to a blower structure (an air pump can also be used to provide strong air flow). Thus, under the neutralization of the air equalizing chamber 121, the plurality of air nozzles 5 blow air downward simultaneously, forming a uniform and large-covered blowing air flow, improving the efficiency of the powder material falling into the stirring bin 11.

[0047] At the same time, in order to prevent the residual powder on the attaching belt 31 from following and returning to the main feeding hopper 21 and the auxiliary feeding hopper 22 again, a cleaning brush 33 is further provided below the blanking area of the attaching belt 31 in the present embodiment. The cleaning brush 33 is fixedly installed in the pre-mixing bin 12, and the bristles of the cleaning brush 33 are in contact with the part of the attaching belt 31 in the lower area. Thus, when the attaching belt 31 moves, the surface residual powder on the attaching belt 31 can be cleaned by means of the cleaning brush 33, ensuring the subsequent use effect of the attaching belt 31.

[0048] In addition, in order to improve the mixing effect, the present embodiment also improves the layered mixing assembly 3. For example, referring to the attached drawings of the specification Figure 6, in order to further avoid the residue of the powder material after the attachment belt 31 passes through the blanking area, in this embodiment, a vibration seat 35 is further arranged in the premixing bin 12. The vibration seat 35 is installed in the premixing bin 12 through an elastic member (such as a spring, a rubber block or a combined structure of a spring and a slide bar). A vibrator is fixedly installed on the vibration seat 35, and a vibration roller is rotatably installed on the vibration seat 35. The vibration roller is in contact with the position of the attachment belt 31 away from the conveying area. The vibration seat 35 drives the corresponding area of the attachment belt 31 to vibrate to shake off the powder material remaining on the surface of the attachment belt 31 downward. At the same time, pressing rollers 36 are further arranged at the positions on both sides of the vibration seat 35 in the premixing bin 12. The pressing rollers 36 are composed of two sets of upper and lower limiting rollers, and both sets of limiting rollers are in rolling cooperation with the attachment belt 31, so that the attachment belt 31 can pass through the two sets of upper and lower limiting rollers, thereby ensuring that the attachment belt 31 in other areas does not vibrate.

[0049] Among them, since the attachment belt 31 is in a continuous running state and the attachment belt 31 is mainly made of rubber material, during operation, static electricity is likely to occur, which will cause excessive adsorption of various powder materials. And due to the uncertainty of the static electricity area, the adsorption effect is also difficult to determine, and the subsequent static electricity is not easy to eliminate, resulting in that the subsequent powder is not easy to separate. For this reason, this embodiment also provides the following solutions. Specifically, an atomizing nozzle 6 is arranged in the lower area of the attachment belt 31, a humidifying bin 124 is arranged in the premixing bin 12 corresponding to the lower area of the attachment belt 31, the atomizing nozzle 6 is arranged in the humidifying bin 124, and the atomizing nozzle 6 is connected to a water pump system. Then, when the attachment belt 31 is running, the area of the humidifying bin 124 is humidified through the atomizing nozzle 6 to increase the humidity of the surface of the attachment belt 31 (it should be noted that it is not necessary to form a large amount of water layer on the surface of the attachment belt 31, otherwise it is easy to form water droplets and affect the attachment effect). Furthermore, the static electricity phenomenon can be effectively reduced. At the same time, by pre-increasing the humidity of the surface of the attachment belt 31, when it passes through the main extension pipe 211 and the secondary extension pipe 221, the adsorption effect of the powder material can be enhanced by means of the tiny water film evenly distributed on the surface of the attachment belt 31, and the mixing uniformity of various powder materials can be improved.

[0050] Furthermore, in order to control the effect of the water film on the surface of the attachment belt 31, referring to the attached Figure 7 to the specification, a wiping roller 7 can also be arranged at the position where the side wall of the humidifying bin 124 cooperates with the attachment belt 31. The wiping roller 7 is rotatably installed at the top end of the side wall of the humidifying bin 124, and the wiping roller 7 is in rolling cooperation with the attachment belt 31. At the same time, the surface of the wiping roller 7 is a sponge layer structure. Then, after the atomizing nozzle 6 humidifies the surface of the attachment belt 31, when the attachment belt 31 moves out of the humidifying bin 124, it can fully contact with the attachment belt 31, and the wiping roller 7 is used to scrape and absorb the excess water on the surface of the attachment belt 31 to ensure that there is no excessive water on the surface of the attachment belt 31.

[0051] Meanwhile, in the method of adjusting the adsorption effect based on the above-mentioned humidity control, in order to ensure the sufficient detachment of the subsequent powder materials, the present embodiment also provides the following technical solutions. Specifically, an air heater 123 is installed in the air equalizing chamber 121. The air heater 123 is used to preheat the gas blown out by the air nozzle 5. Thus, while the air nozzle 5 blows air, the surface of the blanking area of the attachment belt 31 can also be heated to accelerate water evaporation, improve the blanking efficiency, and corresponding heating devices can also be provided on the inner lining of the attachment belt 31 to preheat the attachment belt 31 before it reaches the blanking area, so as to mix the powder materials with each other.

[0052] Since the air nozzle 5 continuously outputs gas into the pre-mixing chamber 12, to ensure the air pressure balance inside the equipment and prevent excessive air from overflowing from the main feeding hopper 21 and the auxiliary feeding hopper 22, the present embodiment also provides the following method. A filter type exhaust pipe 125 is provided in the pre-mixing chamber 12. The filter type exhaust pipe 125 is docked with the fan structure connected to the fan pipeline 122. Among them, the fan pipeline 122 is connected to the output end of the fan structure, the filter type exhaust pipe 125 is connected to the input end of the fan structure, and a filter for filtering powder is provided on the filter type exhaust pipe 125, thereby realizing the internal circulation of air and avoiding the overflow of powder.

[0053] Furthermore, in order to improve the fitting effect between the powder materials and the attachment belt 31, the present embodiment further improves the feeder 2. Specifically, referring to the attached Figure 8 drawing, after adding the corresponding powder materials to the main feeding hopper 21 and the auxiliary feeding hopper 22, a plurality of grinding balls 24 are put into the main feeding hopper 21 and the auxiliary feeding hopper 22. The grinding balls 24 sink under their own weight and gather at the main extension pipe 211 and the auxiliary extension pipe 221. At the same time, a support backing plate 34 is arranged on the inner side of the attachment belt 31. The support backing plate 34 is in sliding contact with the inner side wall of the attachment belt 31, thereby providing a flat and stable support for the attachment belt 31. As the attachment belt 31 moves, the corresponding grinding balls 24 will also roll and move accordingly. On the one hand, it can pre-stir and disperse the powder materials close to the attachment belt 31. On the other hand, under the continuous movement and extrusion of the grinding balls 24 forming a flat laying state, the adhesion strength between the powder materials and the attachment belt 31 can be increased, thereby improving the fusion effect between different layers of powder materials.

[0054] Meanwhile, after adding the grinding balls 24, pressure bags 25 can also be placed in both the main feeding hopper 21 and the auxiliary feeding hopper 22. The pressure bags 25 are filled with multiple groups of metal particles, so that the pressure bags 25 can be laid flat above the corresponding powder materials. On the one hand, it forms a relative seal for the powder materials. On the other hand, it can apply pressure to the powder materials to further increase the adhesion effect between the powder materials and the attachment belt 31.

[0055] It should be noted that the corresponding proportional relationship between the above-mentioned graphene powder material and other auxiliary powder materials can be preset according to requirements, and the corresponding amount of powder materials can be put into the corresponding main hopper 21 and auxiliary hopper 22. Then, by controlling the powder output speeds of the main extension pipe 211 and the auxiliary extension pipe 221, the mixing situation of the powders can be adjusted. For example, by adjusting the relative proportion of the outlet sizes of the auxiliary extension pipe 221 and the main extension pipe 211, or by adjusting the thickness of the output gaps of the main extension pipe 211 and the auxiliary extension pipe 221, the pre-mixing ratio can be adjusted. For the mixing step with a fixed ratio in continuous production, the sizes of the fixed main extension pipe 211 and auxiliary extension pipe 221 and the corresponding output gap sizes can be preset without adjustment. However, for equipment producing different products, corresponding adjustments are required. The adjustment methods can include adjusting the thickness of the corresponding output gaps and controlling the number of the same type of auxiliary hoppers 22 (i.e., repeatedly adding the same auxiliary powder material to increase the layer number and thickness ratio). Among them, this embodiment provides a method for adjusting the output gap. Refer to the appended Figure 8 and Figure 9 , the flat pressing guide plates 23 in the main extension pipe 211 and the auxiliary extension pipe 221 are both movably installed. For example, the flat pressing guide plate 23 in the main extension pipe 211 is slidably installed in the main extension pipe 211, and the flat pressing guide plate 23 in the auxiliary extension pipe 221 is slidably installed in the auxiliary extension pipe 221. And distance adjusters 26 for controlling the movement distance of the flat pressing guide plate 23 are provided on both the main extension pipe 211 and the auxiliary extension pipe 221. Among them, the sliding direction of the flat pressing guide plate 23 is inclined relative to the conveying direction of the conveying area of the attachment belt 31 (since the output gap is not large, even if the height is adjusted, it will not be too large, so the above-mentioned inclination angle is relatively small and approaches parallel, so it is difficult to see in the drawings). In this embodiment, the beam pressing roller 36 can adopt a threaded rod structure or other linear driving devices for control. Then, before actual use, according to the proportional requirements of each powder material, by adjusting the position of the corresponding flat pressing guide plate 23, the cross-sectional size and output gap size of the corresponding main extension pipe 211 or auxiliary extension pipe 221 can be adjusted to adapt to the corresponding ratio.

[0056] It should be noted that, in this embodiment, the powder materials are pre-mixed only by the layered mixing component 3 to avoid the agglomeration of the graphene powder before the final mixing. After the pre-mixing, secondary mixing is required with the help of the stirring component 4. Therefore, there is no need to provide too high precision for the proportion problem at the layered mixing component 3. It is only necessary to ensure that all the powder materials can finally enter the stirring chamber 11. The stirring component 4 includes a stirring shaft 41 and a stirring blade 42. The stirring shaft 41 is rotatably installed in the stirring chamber 11 and is driven to rotate by a drive motor arranged outside the stirring chamber 11, and the stirring blade 42 is fixedly installed on the stirring shaft 41, so as to effectively perform secondary mixing.

[0057] For further information, please refer to the attached manual. Figure 10 and Figure 11 The present embodiment also provides a detailed composition scheme of the attachment belt 31. Specifically, the attachment belt 31 includes a base belt 311 and a thin-walled elastic belt 313. The base belt 311 is located in the inner circle. The base belt 311 is provided with a plurality of groups of filling strips 312 corresponding to the thin-walled elastic belt 313 (by cutting a plurality of groups of slits in parallel on the surface of the integrated base belt 311, a plurality of filling strips 312 connected to the base belt 311 can be formed). The elastic coefficient of the thin-walled elastic belt 313 is greater than the elastic coefficient of the base belt 311, that is, the elastic deformation ability of the thin-walled elastic belt 313 is higher. When the attachment belt 31 does not contact the belt roller 32, the corresponding base belt 31 1 and the filling strips 312 are in a straight state, and the filling strips 312 are close to each other, forming an effective support for the thin-walled elastic belt 313. At this time, the surface of the base belt 311 is in an initially contracted straight state, and when the attachment belt 31 gradually approaches the belt roller 32 in the blanking area, due to the formation of an arc area, the diameter of the attachment belt 31 gradually increases from the inside to the outside, so the outermost thin-walled elastic belt 313 is stretched, and the corresponding filling strips 312 are in a mutually open state, so that the powder material previously spread on the surface of the attachment belt 31 can be better separated from the thin-walled elastic belt 313 when the thin-walled elastic belt 313 is stretched, thereby improving the blanking effect.

[0058] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for preparing a graphene powder material, characterized in that: A secondary mixing device is used to mix graphene powder and auxiliary powder. The secondary mixing device comprises a main upper hopper (21), an auxiliary upper hopper (22) and an attachment belt (31). The attachment belt (31) is made of rubber. A conveying area is formed above the attachment belt (31). A material drop area is formed at the conveying end of the conveying area of ​​the attachment belt (31). A main extension tube (211) is provided at the bottom of the main upper hopper (21). A auxiliary extension tube (221) is provided at the bottom of the auxiliary upper hopper (22). The main extension tube (211) and the auxiliary extension tube (221) are connected to each other. The bottom ports are arranged corresponding to the conveying area of ​​the attachment belt (31), the areas corresponding to the attachment belt (31) on both sides of the main extension tube (211) and the areas corresponding to the attachment belt (31) on both sides of the auxiliary extension tube (221) are respectively formed with input gaps and output gaps, and the input gaps and the output gaps are arranged in sequence along the conveying direction of the attachment belt (31), and along the conveying direction of the attachment belt (31), the output gaps of the main extension tube (211) and the auxiliary extension tube (221) are arranged to increase in sequence, and the output gaps of the main extension tube (211) and the auxiliary extension tube (221) are both provided with flattening guide plates (23); The preparation method comprises the following steps: Step 1: putting graphene powder into the main upper hopper (21), so that the powder material in the main upper hopper (21) contacts the attachment belt (31) through the main extension tube (211), and then driving the attachment belt (31) to move, so that excess graphene powder is blocked in the main extension tube (211) through the output gap of the main extension tube (211), and the graphene powder layer attached to the attachment belt (31) is output; Step 2: After the graphene powder layer reaches the bottom of the secondary extension tube (221), the auxiliary powder is put into the secondary upper hopper (22), so that the auxiliary powder in the secondary upper hopper (22) contacts the graphene powder layer already formed on the attachment belt (31) through the secondary extension tube (221), and the attachment belt (31) is continuously driven to be transported, so that excess auxiliary powder is blocked in the secondary extension tube (221) through the output gap of the secondary extension tube (221), and the auxiliary powder layer attached to the graphene powder layer on the attachment belt (31) is output; Step 3: Control the attachment belt (31) to continuously move, so that the graphene powder layer and the auxiliary powder layer superimposed thereon are transported backward together, until they are transported to the material drop area, and the graphene powder material and the auxiliary powder material are separated from the attachment belt (31) and fall down; Step 4: The powder material separated from the attachment belt (31) falls into the mixing bin (11) for collection. After all the materials in the main upper hopper (21) and the auxiliary upper hopper (22) have been discharged, the mixing component (4) is started to perform secondary mixing on the pre-mixed powder material in the mixing bin (11); Step 5: Close the stirring assembly (4), open the closed door at the bottom discharge port of the stirring bin (11), and take out the mixed powder material.

2. A method for preparing graphene powder material according to claim 1, characterized in that: The secondary mixing device comprises a mixer (1) and a loader (2). The mixer (1) comprises a stirring chamber (11) and a pre-mixing chamber (12). The pre-mixing chamber (12) is arranged on the stirring chamber (11). The loader (2) comprises a main hopper (21) and a secondary hopper (22). Both the main hopper (21) and the secondary hopper (22) are installed on the pre-mixing chamber (12). A stirring assembly (4) is arranged in the stirring chamber (11). A layered mixing assembly (3) is arranged in the pre-mixing chamber (12). The layered mixing assembly (3) comprises an attachment belt (31) and a belt roller (32). The attachment belt (31) is a belt-type annular structure. At least two groups of belt rollers (32) are arranged. The belt rollers (32) support the attachment belt (31) to form a conveying structure.

3. A method for preparing graphene powder material according to claim 2, characterized in that: An air nozzle (5) is arranged outside the blanking area of ​​the attachment belt (31), and a plurality of groups of the air nozzles (5) are arranged. An air equalization bin (121) is arranged in the pre-mixing bin (12), and a fan duct (122) is connected to the air equalization bin (121), and the fan duct (122) is connected to a fan structure, so that the air nozzle (5) blows air downwards through the fan structure and blows air toward the arc surface at the matching position between the attachment belt (31) and the belt roller (32) in the blanking area, so as to blow away the powder material on the attachment belt (31).

4. A method for preparing graphene powder material according to claim 3, characterized in that: A cleaning brush (33) is provided below the material dropping area of ​​the attachment belt (31), and the bristles of the cleaning brush (33) are in contact with the attachment belt (31). When the attachment belt (31) moves, the cleaning brush (33) is used to clean the residual powder material on the surface of the attachment belt (31). A vibration seat (35) is also provided in the pre-mixing bin (12). The vibration seat (35) is installed in the pre-mixing bin (12) via an elastic member. A vibrator is fixedly installed on the vibration seat (35). A vibration roller is rotatably installed on the vibration seat (35). The vibration roller is in contact with a position of the attachment belt (31) away from the conveying area, and the corresponding area of ​​the attachment belt (31) is driven to vibrate through the vibration seat (35) to shake the residual powder material on the surface of the attachment belt (31) downward.

5. A method for preparing graphene powder material according to claim 4, characterized in that: A humidifying chamber (124) is provided in the area below the attachment belt (31), and an atomizing nozzle (6) is provided in the humidifying chamber (124). When the attachment belt (31) passes through the humidifying chamber (124), the humidity of the surface of the attachment belt (31) is increased by the atomizing nozzle (6). An air heater (123) is installed in the gas equalizing chamber (121), and the gas before being blown out by the gas nozzle (5) is heated by the air heater (123). A filtering exhaust pipe (125) is provided in the pre-mixing chamber (12), and the filtering exhaust pipe (125) is connected to a fan structure connected to the fan pipe (122).

6. A method for preparing graphene powder material according to claim 5, characterized in that: A wiping roller (7) is provided at a position where the side wall of the humidifying chamber (124) cooperates with the attachment belt (31); the wiping roller (7) is rotatably mounted on the top of the side wall of the humidifying chamber (124); the surface of the wiping roller (7) is a sponge layer structure; and excess moisture on the surface of the attachment belt (31) is scraped off and absorbed through the rolling cooperation between the wiping roller (7) and the attachment belt (31).

7. A method for preparing graphene powder material according to claim 6, characterized in that: In the step 1 and the step 2, after the corresponding powder material is added to the main upper hopper (21) and the auxiliary upper hopper (22), a plurality of grinding balls (24) are added to the main upper hopper (21) and the auxiliary upper hopper (22), so that the grinding balls (24) sink under the action of their own weight and gather at the main extension tube (211) and the auxiliary extension tube (221). A support pad (34) is provided on the inner side of the attachment belt (31). The movement of the attachment belt (31) cooperates with the corresponding grinding balls (24) to cause the grinding balls (24) to roll and move accordingly, thereby stirring and squeezing the corresponding powder material downward.

8. A method for preparing graphene powder material according to claim 7, characterized in that: After the grinding balls (24) are added, a covering bag (25) is placed in both the main upper hopper (21) and the auxiliary upper hopper (22), wherein the covering bag (25) is filled with a plurality of groups of metal particles so that the covering bag (25) is laid flat on the corresponding powder material.

9. A method for preparing graphene powder material according to claim 8, characterized in that: The flattening guide plate (23) in the main extension tube (211) is slidably installed in the main extension tube (211), and the flattening guide plate (23) in the secondary extension tube (221) is slidably installed in the secondary extension tube (221), and both the main extension tube (211) and the secondary extension tube (221) are provided with a distance regulator (26) for controlling the movement of the flattening guide plate (23), wherein the sliding direction of the flattening guide plate (23) is inclined relative to the conveying direction of the conveying area of ​​the attachment belt (31), and the position of the corresponding flattening guide plate (23) is controlled by the distance regulator (26) to adjust the cross-sectional size and output gap size of the corresponding main extension tube (211) or secondary extension tube (221).

10. A method for preparing graphene powder material according to claim 9, characterized in that: The attachment belt (31) comprises a base belt (311) and a thin-walled elastic belt (313); the base belt (311) is located in the inner circle; a plurality of groups of filling strips (312) are arranged at positions of the base belt (311) corresponding to the thin-walled elastic belt (313); the elastic coefficient of the thin-walled elastic belt (313) is greater than the elastic coefficient of the base belt (311); when the attachment belt (31) moves to the belt roller (32) in the blanking area, an arc area is formed, and the thin-walled elastic belt (313) is stretched.

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