A method for producing a recycled graphite puck

Abstract

The application discloses a preparation method of regenerated graphite round cake and belongs to the technical field of inorganic nonmetallic materials and products thereof. The method comprises raw material pretreatment, batching, mixing and kneading, cooling, mould pressing, primary baking, impregnation, secondary baking, mechanical processing and inspection and packaging. The raw material pretreatment comprises crushing, screening and purification. The crushing adopts a crusher. Compared with a traditional planar screening plate, the application effectively increases the screening area. Meanwhile, under the action of multiple circular-truncated-cone-shaped mesh covers in a single area, the entering powder is at different heights, the entering powder is layered, the flowability of the powder on the screening plate is further increased, the screening efficiency is improved, the screening precision is improved, and the relative force between powder molecules is reduced. The circular-truncated-cone-shaped mesh cover in the rotating state not only rotates, but also swings. The mesh cover and the screening plate in the swinging state cooperate with each other, the material keeps multiple movement states, and the jamming phenomenon is reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of inorganic non-metallic materials and their products, and particularly relates to a method for preparing recycled graphite discs. Background Technology

[0002] Graphite squares and round cakes are made from graphite as the main raw material, combined with binders. They have the characteristics of high temperature resistance, strong thermal conductivity, small coefficient of thermal expansion, good chemical stability, and long service life. They are used in negative electrode plates, boiler carbon bricks, heat exchangers, condensing devices, coolers, heaters, filters, and water pump configurations. They can also be used in solar thermal fields, petrochemicals, metallurgy, synthetic fibers, molds, casting, and semiconductor industries.

[0003] In the industrial production of carbon, the waste materials generated during the high-temperature purification and graphitization process, such as waste graphite crucibles, broken graphite electrodes, and graphitization dust collection powder, have extremely low recycling rates. Furthermore, during the screening process, the small particle size of the graphite powder produced by crushing results in strong intermolecular forces, which easily leads to accumulation, affecting screening efficiency and causing jamming.

[0004] Based on this, the present invention designs a method for preparing recycled graphite discs to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to address the extremely low recycling rate of waste materials such as waste graphite crucibles, broken graphite electrodes, and graphitization dust generated during high-temperature purification and graphitization in the carbon industry. Furthermore, during the sieving process, the small particle size and strong intermolecular forces of the graphite powder particles produced by crushing lead to easy accumulation, which not only affects sieving efficiency but also causes problems such as poor embedding. Therefore, this invention proposes a method for preparing recycled graphite discs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing recycled graphite discs includes raw material pretreatment, batching, mixing, cooling, molding, primary firing, impregnation, secondary firing, machining, and inspection and packaging. The raw material pretreatment includes crushing, screening, and purification. Crushing is performed using a crusher, and screening is performed using a multi-stage screening device. The multi-stage screening device includes a screening frame connected to one side of the crusher. Sliding grooves are provided on both sides of the top of the screening frame. Sliding blocks are slidably connected in both sliding grooves. A common screening component is provided above the two sliding blocks. Two triangular pads with the same inclination but different heights are provided between the bottom of the screening component and the two sliding blocks to tilt the end of the screening component away from the crusher downwards.

[0007] As a further description of the above technical solution: The screening assembly includes a screening box connected to the inclined surfaces of two triangular pads. A screening component is snapped into the opening at the top of the screening box. The screening component includes a screening plate snapped into the opening at the top of the screening box. The screening plate is divided into multiple areas based on the powder screening requirements. Each area on the screening plate has screening holes. The diameter of the screening holes on the screening plate gradually increases along the downward inclination direction. The powder is screened in multiple stages along the inclined screening plate.

[0008] As a further description of the above technical solution: Each area of ​​the screening plate has multiple screening ports. The inner wall of each screening port has an annular groove. A cross-shaped adapter ring is rotatably connected to the screening port through the annular groove. A frustum-shaped mesh cover is connected to the top of the cross-shaped adapter ring. The mesh aperture of the frustum-shaped mesh cover is equal to the screening aperture of the area.

[0009] As a further description of the above technical solution: The bottom of the screening plate is connected to two adjacent areas with grading partitions. The bottom of the screening box is provided with a discharge port corresponding to the grading partitions. The bottom of the screening box is connected to a funnel bucket corresponding to the discharge port, which is used to gather the powder falling through the screening plate to the discharge port.

[0010] As a further description of the above technical solution: The bottom of the screening box is connected to a first adapter frame, the inner side of the first adapter frame is rotatably connected to a hydraulic cylinder, and the other end of the hydraulic cylinder is rotatably connected to a second adapter frame, which is connected to the screening frame.

[0011] As a further description of the above technical solution: The screening box has multiple telescopic holes on its side end face. The same torsion assembly is slidably connected in the multiple telescopic holes. The torsion assembly includes multiple driven toothed plates that are slidably connected in the multiple telescopic holes. The inner top of the frustum-shaped mesh cover is connected to an umbrella-shaped shaft. The other end of the umbrella-shaped shaft is fitted with a driving gear. The driving gear meshes with the corresponding driven toothed plate. The ends of the multiple driven toothed plates are connected to the same linkage frame, which is connected to the screening frame.

[0012] As a further description of the above technical solution: The screening box has a strip-shaped opening on its side end face. An interference component is slidably connected inside the strip-shaped opening. The interference component includes an interference plate slidably connected inside the strip-shaped opening. The interference plate is suspended above the screening plate. The bottom of the interference plate has multiple micro-holes. The end of the interference plate is connected to a side support frame. The interference plate is connected to the screening frame through the side support frame.

[0013] As a further description of the above technical solution: The interference component also includes multiple piston canisters connected to the screening frame. Each piston canister has a piston hole on its end face, and a piston rod is fitted inside the piston hole. The end of the piston rod is connected to a piston disc, which is fitted inside the piston canister. The other ends of the multiple piston rods are connected to the same linkage rod, and the multiple piston rods are connected to the bottom of the screening box through the same linkage rod. The other ends of the multiple piston canisters are connected through the same pressure diversion pipe. The interference plate has a hollow internal structure, and the interference plate is connected to the pressure diversion pipe through an air pipe.

[0014] As a further description of the above technical solution: The raw materials in the formulation include graphite waste, coal tar pitch and modified phenolic resin. The graphite waste includes waste graphite crucibles, broken graphite electrodes, calcined petroleum coke insulation waste and graphitized dust collection powder.

[0015] As a further description of the above technical solution: The kneading is carried out in a kneading pot, and the molding is performed using a vibration molding machine.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In this invention, the design of the frustum-shaped mesh cover can increase the screening surface in the limited lateral space, effectively increasing the screening area compared with the traditional planar screening plate. At the same time, the action of multiple frustum-shaped mesh covers in a single area can make the incoming powder at different heights, which can play a stratification role for the incoming powder, further increasing the flowability of the powder on the screening plate, improving screening efficiency, improving screening accuracy, and reducing the relative force between powder molecules. The frustum-shaped mesh cover in the rotating state not only rotates on its own but also has an oscillating behavior, which cooperates with the screening plate in the oscillating state to keep the material in a variety of motion states and reduce the phenomenon of jamming.

[0017] 2. In this invention, the powder initially falling into the screening box will be conveyed downward along the screening plate. The oscillation behavior of the screening plate causes the powder to continuously jump and roll on the screen surface, reducing the contact resistance between the particles and the screening holes. The oscillation causes particles of different sizes to be stratified according to the settling velocity. Fine particles preferentially pass through the screening holes of the corresponding screening area, thereby achieving a multi-stage screening effect and being able to obtain powder of various specifications at the same time.

[0018] 3. In this invention, when the hydraulic cylinder pushes the screening plate, multiple piston tanks will blow air into the screening plate, thereby blowing airflow into the powder through micropores. The airflow utilizes the difference in carrying capacity of airflow for particles of different sizes to assist in the separation of ultrafine particles or light impurities. The airflow impacts the screen surface, breaking the embedded state of particles and screening holes, preventing blockage. At the same time, when the interference plate generates suction, it can remove particles embedded in the screening holes to a certain extent. During the relative movement between the screening plate and the interference plate, the interference plate can further play a role in stratifying the powder. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a method for preparing recycled graphite discs proposed in this invention. Figure 2 This is a schematic diagram of the structure of a method for preparing a recycled graphite disc proposed in this invention from another perspective; Figure 3 This is a schematic diagram of the sieving component in the method for preparing recycled graphite discs proposed in this invention. Figure 4 This is a schematic diagram of the sieving component under sieving in the method for preparing recycled graphite discs proposed in this invention; Figure 5 This is a schematic diagram of the sieving component in the method for preparing recycled graphite discs proposed in this invention, viewed from another perspective. Figure 6 This is a schematic diagram of the disassembled sieving component in the method for preparing recycled graphite discs proposed in this invention. Figure 7 This is a schematic diagram of the torsion component in the method for preparing a recycled graphite disc proposed in this invention.

[0020] Legend: 1. Crusher; 2. Screening frame; 3. Sliding chute; 4. Screening assembly; 401. Screening box; 402. Grading partition; 403. Discharge port; 404. Hydraulic components; 4041. First transfer frame; 4042. Hydraulic cylinder; 4043. Second transfer frame; 405. Screening component; 4051. Screening plate; 4052. Annular trough; 4053. Screening port; 4054. Frustum-shaped mesh cover; 4055. Cross-shaped transfer ring; 406. Horn bucket; 5. Torsion assembly; 501. Umbrella-shaped shaft; 502. Drive gear; 503. Driven gear plate; 504. Linkage frame; 6. Strip-shaped inlet; 7. Interference assembly; 701. Interference plate; 702. Side support frame; 703. Piston tank; 704. Piston rod; 705. Linkage rod; 706. Pressure diversion pipe. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see the appendix Figure 1 - Appendix Figure 7 This invention provides a technical solution: a method for preparing recycled graphite discs, including raw material pretreatment, batching, mixing, cooling, molding, primary firing, impregnation, secondary firing, machining, and inspection and packaging. The raw material pretreatment includes crushing, screening, and purification. Crushing is performed using a crusher 1, and screening is performed using a multi-stage screening device. The multi-stage screening device includes a screening frame 2 connected to one side of the crusher 1. Sliding grooves 3 are provided on both sides of the top of the screening frame 2. Sliding blocks are slidably connected in both sliding grooves 3. The same screening component 4 is provided above the two sliding blocks. Two triangular pads with the same inclination and different heights are provided between the bottom of the screening component 4 and the two sliding blocks to make the end of the screening component 4 away from the crusher 1 tilt downwards.

[0023] Specifically, the screening assembly 4 includes a screening box 401 connected to the inclined surfaces of two triangular pads. A screening component 405 is snapped into the opening at the top of the screening box 401. The screening component 405 includes a screening plate 4051 snapped into the opening at the top of the screening box 401. The screening plate 4051 is divided into multiple areas based on the powder screening requirements. Each area on the screening plate 4051 has screening holes. The diameter of the screening holes on the screening plate 4051 gradually increases along the downward inclination direction. The powder undergoes multi-stage screening along the inclined screening plate 4051. Each area on the screening plate 4051 has multiple screening ports 4053. The inner wall of the screening port 4053 has an annular groove 4052. A cross-shaped adapter ring 4055 is rotatably connected to the screening port 4053 through the annular groove 4052. The top of the U-shaped adapter ring 4055 is connected to a frustum-shaped mesh cover 4054. The mesh aperture of the frustum-shaped mesh cover 4054 is equal to the sieve aperture of the area. The bottom of the sieve plate 4051 is connected to a grading partition 402 corresponding to two adjacent areas. The bottom of the sieve box 401 is provided with a discharge port 403 corresponding to the grading partition 402. The bottom of the sieve box 401 is connected to a funnel hopper 406 corresponding to the discharge port 403, which is used to collect the powder falling through the sieve plate 4051 and gather it towards the discharge port 403. The bottom of the sieve box 401 is connected to a first adapter frame 4041. The inner side of the first adapter frame 4041 is rotatably connected to a hydraulic cylinder 4042. The other end of the hydraulic cylinder 4042 is rotatably connected to a second adapter frame 4043. The second adapter frame 4043 is connected to the sieve frame 2.

[0024] The specific implementation method is as follows: A guide plate is installed on the side end of the crusher 1 corresponding to the screening box 401. The powder generated by the crusher 1 from crushing graphite waste flows into one end of the inner side of the screening box 401 along the guide plate. The hydraulic cylinder 4042 is controlled in advance to operate, and the hydraulic cylinder 4042 performs reciprocating extension and retraction movements. During this process, the two ends of the hydraulic cylinder 4042 rotate in the corresponding directions inside the first adapter 4041 and the second adapter 4043, respectively. When the hydraulic cylinder 4042 extends, the extension and retraction end of the hydraulic cylinder 4042 generates a thrust on the screening box 401 through the first adapter 4041. When cylinder 4042 retracts, the extension end of hydraulic cylinder 4042 pulls screening box 401 through first adapter frame 4041. Under the action of tension and thrust, the bottom of screening box 401 slides stably in two sliding grooves 3 through two triangular pads and two sliding blocks. The regular working procedure of hydraulic cylinder 4042 drives screening box 401 to swing in the direction of sliding groove 3. Since screening plate 4051 in screening box 401 is in an inclined state under the support of two triangular pads, the powder initially falling into screening box 401 will be transmitted downward along screening plate 4051.

[0025] Specifically, the side end face of the screening box 401 is provided with multiple telescopic holes, and the same torsion component 5 is slidably connected in the multiple telescopic holes. The torsion component 5 includes multiple driven toothed plates 503 that are slidably connected in the multiple telescopic holes. The inner top of the frustum-shaped mesh cover 4054 is connected to an umbrella-shaped shaft 501. The other end of the umbrella-shaped shaft 501 is fitted with a drive gear 502. The drive gear 502 meshes with the corresponding driven toothed plate 503. The ends of the multiple driven toothed plates 503 are connected to the same linkage frame 504, and the linkage frame 504 is connected to the screening frame 2.

[0026] The specific implementation method is as follows: During the swinging process of the screening box 401 driving the screening plate 4051, since the passive toothed plate is in a relatively stationary state, the screening plate 4051 drives multiple frustum-shaped mesh covers 4054 to swing synchronously through multiple cross-shaped transition rings 4055. The multiple frustum-shaped mesh covers 4054 drive multiple driving gears 502 to move relative to multiple driven toothed plates 503 through multiple umbrella-shaped shafts 501. Utilizing the meshing relationship between the driving gears 502 and the driven toothed plates 503, it is possible to... The frustum-shaped screen 4054 is driven to rotate stably within the annular groove 4052 via a cross-shaped adapter ring 4055. The design of the frustum-shaped screen 4054 increases the screening surface in its area within a limited lateral space, effectively increasing the screening area compared to the traditional flat screening plate 4051. At the same time, the action of multiple frustum-shaped screens 4054 in a single area can keep the incoming powder at different heights, thus stratifying the incoming powder and further increasing the flowability of the powder on the screening plate 4051.

[0027] Specifically, the side end face of the screening box 401 has a strip-shaped opening 6, and an interference component 7 is slidably connected within the strip-shaped opening 6. The interference component 7 includes an interference plate 701 slidably connected within the strip-shaped opening 6, the interference plate 701 being suspended above the screening plate 4051, and multiple micro-holes opening at the bottom of the interference plate 701. A side support frame 702 is connected to the end of the interference plate 701, and the interference plate 701 is connected to the screening frame 2 via the side support frame 702. The interference component 7 also includes multiple piston canisters 703 connected to the screening frame 2. A piston hole is provided on the end face, and a piston rod 704 is sleeved in the piston hole. The end of the piston rod 704 is connected to a piston disc, which is sleeved in the piston can 703. The other ends of multiple piston rods 704 are connected to the same linkage rod 705. Multiple piston rods 704 are connected to the bottom of the screening box 401 through the same linkage rod 705. The other ends of multiple piston cans 703 are connected through the same pressure diversion pipe 706. The interference plate 701 has a hollow structure inside, and the interference plate 701 and the pressure diversion pipe 706 are connected through an air pipe.

[0028] The specific implementation method is as follows: the micro-holes at the bottom of the interference plate 701 are smaller than the minimum particle size of the powder. When the hydraulic cylinder 4042 pulls the screening box 401 through the first adapter frame 4041, the screening box 401 simultaneously generates a pulling force on multiple piston rods 704 through the linkage rod 705. The multiple piston rods 704 pull multiple piston discs to slide in multiple piston cans 703 respectively. The multiple piston cans 703 draw air from the interference plate 701 through the pressure diversion pipe 706 and the air pipe. The interference plate 701 generates suction through the micro-holes. Therefore, when the hydraulic cylinder 4042 pushes the screening plate 4051, the multiple piston cans 703 will blow air into the screening plate 4051, thereby blowing air into the powder through the micro-holes. The airflow utilizes the difference in the carrying capacity of airflow for particles of different sizes to assist in the separation of ultrafine particles or light impurities. The airflow impacts the screen surface, breaking the embedded state of particles and screening holes and preventing blockage.

[0029] Specifically, the raw materials in the ingredients include graphite waste, coal tar pitch and modified phenolic resin. The graphite waste includes waste graphite crucibles, broken graphite electrodes, calcined petroleum coke insulation waste and graphitized dust powder. The mixture is kneaded in a kneading pot and the molding is done using a vibration molding machine.

[0030] The specific implementation method is as follows: The graphite crucible waste is in block form and is transported to the production workshop by truck. The calcined petroleum coke insulation waste is in granular form and is packaged in ton bags and transported to the production workshop by truck. Because the graphite crucible waste and the calcined petroleum coke insulation waste are different in shape and size, the two raw materials are crushed, screened, purified and pretreated respectively. Crushing and screening: Graphite crucible waste is shoveled into the feeding hopper of double roll crusher 1 by a loader for crushing. Calcined petroleum coke insulation waste is fed into the feeding hopper of double roll crusher 1 by bottom feeding of ton bag for crushing. The crushed powder is conveyed to the vibrating screen by a closed elevator for screening, and three different particle materials of 5-10mm, 1-5mm and below 1mm are screened out respectively. The undersize material enters the purification process, and the oversize material is returned to the crushing process. After purification and screening, the powder is conveyed in a closed system to a gravity screening purification machine, a color sorting purification machine, and a magnetic separation purification device for purification to remove various impurities such as silicon carbide, small stones, and iron filings. The purified powder of different particle sizes is temporarily stored in ton bags for subsequent production processes of recycled graphite crucibles, recycled graphite square boxes, siliconized graphite crucibles, and new carbon raisers. Regenerated graphite crucible production line Raw materials include pretreated graphite crucible waste, calcined petroleum coke insulation waste, etc. (65-80%), and coal tar pitch, phenolic resin, dextrin, stearic acid, silica powder, and various binders (20-35%). Process Introduction The ingredients are prepared by pre-processing graphite powder of different particle sizes and then feeding it into the batching hopper in a certain formula ratio using a bottom feeding method in ton bags. Mixing involves transporting and injecting the granules from the batching hopper into the mixing pot. To ensure that the various raw materials are mixed evenly and that solid carbonaceous materials of different particle sizes are mixed and filled evenly, thereby increasing the density of the mixture, the mixture is first stirred and dry-mixed in the mixing pot for 20 to 35 minutes. Molten asphalt is added to the dry-mixed material. The asphalt is transported to asphalt storage tanks by tanker trucks and heated by a biomass thermal oil boiler to keep it warm. The mixture is then stirred and kneaded for 40-55 minutes. This step is called wet mixing. The wet mixing process requires heat preservation. All kneading pots are heated and kept warm by a biomass thermal oil boiler, with the pot temperature at about 170-180℃. Wet mixing allows the liquid asphalt to be evenly coated and wetted on the surface of the particles, forming an asphalt bonding layer that binds all the materials together, thus forming a homogeneous plastic paste, which is beneficial for molding. Some coal tar pitch penetrates into the internal pores of the carbonaceous material, further improving the density and adhesion of the paste. Cooling: The mixed paste is cooled to about 120°C in a paste cooler. After molding and cooling, the paste is fed into the molding equipment via a conveyor belt for molding. After the time reaches the process requirements, it is demolded and pushed out, finally forming a recycled graphite crucible blank with a certain shape, size, density and strength. The roasting process is carried out in an open annular roasting furnace using natural gas as fuel. The purpose is to remove the volatiles in the raw product. At high temperatures, the asphalt cokes to give the carbon blocks a fixed shape and improve the electrical conductivity and various physicochemical properties of the carbon body. The roasting process can be divided into three different temperature ranges: 20℃-200℃, 200℃-550℃, and 550℃-950℃. At 20℃-200℃, which is the initial stage of roasting, the internal stress of the charcoal block is released. Due to the presence of asphalt, the charcoal block will soften at this stage, and the filling material in the furnace will ensure that the charcoal block does not deform. Between 200℃ and 550℃, as the temperature continues to rise, the volatiles of asphalt will be released. Between 350℃ and 550℃, the volatiles are released to the maximum extent. After continuous decomposition of heavy materials, the volatiles will burn in the fire channel through the filler and refractory brick joints. Between 550℃ and 950℃, asphalt transforms from semi-coke to pitch coke. During continuous roasting to above 750℃, the different reaction rates between coke and pitch coke are reduced. When the temperature reaches 950℃, the true density standard requirements of the product can be met. The recycled graphite crucibles are conveyed into the calcination workshop and manually grouped. During the furnace loading process, a multi-functional calcination crane transports one group of rough blanks at a time and loads them into the calcination furnace. The loading and unloading of the filler material is completed by the multi-functional calcination crane group. According to the established schedule, the calcination furnace chamber with the rough blanks and filler material is connected to the flame system for calcination. The entire heating process is controlled by a computer. After calcination, the furnace chamber moves forward along a circular route, separates from the flame system, and enters the natural cooling process. After the specified time, the blanks are unloaded. When the blanks are unloaded, the multi-functional calcination crane first removes the covering filler material, and then the blanks in the furnace are lifted out in batches. The time from loading the rough blanks into the furnace, calcination, cooling to unloading is about 50 days. Impregnation involves placing the rough blank in a pressure vessel and, under specific pressure and temperature conditions, immersing it in liquid impregnating agent bitumen, which penetrates into the pores of the rough blank. The purpose of impregnation is to reduce the porosity of the rough blank, increase the bulk density and mechanical strength of the product, and improve its electrical and thermal conductivity. The main processes are as follows: After cleaning the surface of the roasted semi-finished product, it is placed in an iron basket, weighed first, and then placed in a preheating box. It is preheated at a temperature of 260-320℃ and kept at that temperature for more than 4 hours. The oxidation temperature of carbon products is 430℃. Under the premise of ensuring that the product does not oxidize, the higher the preheating temperature, the better. If the temperature is low, the viscosity of the coal tar pitch will be high, which will affect the weight gain of the product. After preheating, the product, along with the iron basket, is quickly placed into the impregnation tank. The impregnation tank has been preheated to over 100°C before the product is placed in. The tank lid is closed and a vacuum is drawn. The vacuum level is required to be above 600 mmHg. During high-pressure impregnation, the vacuum level is required to be above 650 mmHg and maintained for 30-60 minutes, generally around 45 minutes. The higher the vacuum level, the better, but the time should not be too long, otherwise it will affect the temperature of the impregnation tank. After vacuuming is completed, put coal tar pitch heated to 160-180℃ into the impregnation tank. If the high-pressure impregnation tank is equipped with an auxiliary tank, the oil can be released while vacuuming and the liquid level indicator light can be used to control the liquid level in the tank. If there is no auxiliary tank, the liquid level of the coal tar pitch should be more than 150 mm above the top of the product. If there is an auxiliary tank, the liquid level should be more than two-thirds of the height of the auxiliary tank. After adding coal tar pitch, check the compressed air pipeline for water. If water is present, drain it to prevent affecting weight gain. The pressurization time for various products depends on the diameter and thickness of the product. Generally, pressurize at 0.4-1.27 MPa and maintain for 1-4 hours. For impregnation pressurization, compressed air can be used at normal pressure, and nitrogen can be used at high pressure. At this time, the temperature of the impregnation tank is about 150-180℃. After pressurization, the impregnating agent is returned to the storage tank. Then, use compressed air to blow and return all the impregnating agent. Add water to cool it down. When the lid of the impregnation tank is no longer hot to the touch, drain the water from the impregnation tank. After draining, the impregnation tank should be depressurized and the pressure gauge should indicate zero before the product can be removed from the tank. Weigh and calculate the weight gain rate; qualified products are stacked and transferred for re-roasting. Secondary roasting is a process in which the impregnated roasted product is roasted again to carbonize the pitch impregnated in the pores of the roasted product. The secondary roasting process is basically the same as the primary roasting process, but no filler is required when loading the furnace. The roasting temperature is 700-800℃, and the corresponding roasting cycle is shortened to 120-140h. The main difference between secondary roasting and primary roasting is that the product after secondary roasting has been impregnated after primary roasting, and the geometric shape of the product is fixed. There will be no overall deformation during secondary roasting. In addition, the thermal conductivity of the impregnated product is higher than that of the original product, and the heat treatment speed of secondary roasting is faster than that of primary roasting. Machining is the process of surface finishing of a product to achieve the specified outer diameter and surface finish. The product blanks entering the machining production line are first milled and ground on the sides by a special milling machine. Then, they are subjected to precision milling of the sides and rough and fine machining of irregular surfaces, precision flattening of the end face, and other processing steps. The processed graphite products are weighed and printed with specifications, weight, and batch number. Inspection and packaging: Inspect the polished products. Pack the qualified products and return the unqualified products to the pre-processing system for further processing.

[0031] Working principle and usage: A guide plate is installed on the side of the crusher 1 corresponding to the screening box 401. The powder generated by the crusher 1 from crushing graphite waste flows along the guide plate into one end of the inner side of the screening box 401. The hydraulic cylinder 4042 is controlled in advance to operate, and the hydraulic cylinder 4042 performs a reciprocating telescopic motion. During this process, the two ends of the hydraulic cylinder 4042 rotate in the corresponding directions inside the first adapter 4041 and the second adapter 4043, respectively. When the hydraulic cylinder 4042 extends, the telescopic end of the hydraulic cylinder 4042 generates a thrust on the screening box 401 through the first adapter 4041. When the hydraulic cylinder 4042 retracts, the telescopic end of the hydraulic cylinder 4042 pulls the screening box 401 through the first adapter 4041. Under the action of the pulling and pushing forces, the screening box 401 is screened. The bottom of the screening box 401 is stably slidable in two sliding grooves 3 by two triangular pads and two sliding blocks. The hydraulic cylinder 4042 drives the screening box 401 to swing in the direction of the sliding groove 3. Since the screening plate 4051 inside the screening box 401 is in an inclined state under the support of the two triangular pads, the powder initially falling into the screening box 401 will be transmitted downward along the screening plate 4051. The swinging behavior of the screening plate 4051 causes the powder to continuously jump and roll on the screen surface, reducing the contact resistance between the particles and the screening holes. The swinging causes particles of different sizes to be stratified according to the settling velocity. Fine particles preferentially pass through the screening holes of the corresponding screening area, thereby achieving a multi-stage screening effect and being able to obtain powder of various specifications at the same time. During the oscillation of the screening plate 4051 driven by the screening box 401, since the passive toothed plate is in a relatively stationary state, the screening plate 4051 drives multiple frustum-shaped screens 4054 to oscillate synchronously through multiple cross-shaped transition rings 4055. The multiple frustum-shaped screens 4054 drive multiple driving gears 502 through multiple umbrella-shaped shafts 501 to move relative to multiple driven toothed plates 503. Utilizing the meshing relationship between the driving gears 502 and the driven toothed plates 503, the frustum-shaped screens 4054 can be driven to rotate stably within the annular groove 4052 through the cross-shaped transition rings 4055. The design of the frustum-shaped screens 4054 allows for limited lateral movement. Within the space, the screening surface of its area is increased, which effectively increases the screening area compared with the traditional flat screening plate 4051. At the same time, under the action of multiple frustum-shaped mesh covers 4054 in a single area, the incoming powder can be placed at different heights, which plays a stratification role on the incoming powder. This can further increase the flowability of the powder on the screening plate 4051, improve screening efficiency, improve screening accuracy, and reduce the relative force between powder molecules. The frustum-shaped mesh cover 4054 in the rotating state not only rotates on its own but also has an oscillating behavior, which works in conjunction with the oscillating screening plate 4051 to keep the material in a variety of motion states and reduce the phenomenon of jamming. The micropores at the bottom of the interference plate 701 are smaller than the minimum particle size of the powder. When the hydraulic cylinder 4042 pulls the screening box 401 through the first adapter frame 4041, the screening box 401 simultaneously generates a pulling force on multiple piston rods 704 through the linkage rod 705. The multiple piston rods 704 pull multiple piston discs to slide in multiple piston tanks 703 respectively. The multiple piston tanks 703 draw air from the interference plate 701 through the pressure diversion pipe 706 and the air pipe. The interference plate 701 generates suction through the micropores. Therefore, when the hydraulic cylinder 4042 pushes the screening plate 4051... Multiple piston canisters 703 will blow air into the sieve plate 4051, thereby blowing air into the powder through the micropores. The airflow utilizes the difference in the carrying capacity of airflow for particles of different sizes to help separate ultrafine particles or light impurities. The airflow impacts the sieve surface, breaking the state of the particles stuck in the sieve holes and preventing blockage. At the same time, when the interference plate 701 generates suction, it can remove the particles stuck in the sieve holes to a certain extent. During the relative movement between the sieve plate 4051 and the interference plate 701, the interference plate 701 can further play a role in stratifying the powder.

[0032] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a recycled graphite disc, characterized in that, The process includes raw material pretreatment, batching, mixing, cooling, molding, primary roasting, impregnation, secondary roasting, machining, and inspection and packaging. The raw material pretreatment includes crushing, screening, and purification. Crushing is performed using a crusher (1), and screening is performed using a multi-stage screening device. The multi-stage screening device includes a screening frame (2) connected to one side of the crusher (1). Sliding grooves (3) are provided on both sides of the top of the screening frame (2). Sliding blocks are slidably connected in both sliding grooves (3). The same screening component (4) is provided above the two sliding blocks. Two triangular pads with the same inclination and different heights are provided between the bottom of the screening component (4) and the two sliding blocks to make the end of the screening component (4) away from the crusher (1) tilt downward. The screening assembly (4) includes a screening box (401) connected to the inclined surfaces of two triangular pads. A screening component (405) is snapped into the top opening of the screening box (401). The screening component (405) includes a screening plate (4051) snapped into the top opening of the screening box (401). The screening plate (4051) is divided into multiple areas based on the powder screening requirements. Screening holes are opened in multiple areas on the screening plate (4051). The diameter of the screening holes on the screening plate (4051) gradually increases along the downward direction. The powder is screened in multiple stages along the inclined screening plate (4051). Each area on the sieve plate (4051) is provided with multiple sieve openings (4053). The inner wall of the sieve opening (4053) is provided with an annular groove (4052). A cross-shaped adapter ring (4055) is rotatably connected to the sieve opening (4053) through the annular groove (4052). A frustum-shaped mesh cover (4054) is connected to the top of the frustum-shaped mesh cover (4054). The mesh aperture of the frustum-shaped mesh cover (4054) is equal to the sieve aperture of the area. The screening box (401) has multiple telescopic holes on its side end face. The same torsion assembly (5) is slidably connected in the multiple telescopic holes. The torsion assembly (5) includes multiple driven toothed plates (503) that are slidably connected in the multiple telescopic holes. The inner top of the frustum-shaped mesh cover (4054) is connected to an umbrella-shaped shaft (501). The other end of the umbrella-shaped shaft (501) is fitted with a drive gear (502). The drive gear (502) meshes with the corresponding driven toothed plate (503). The ends of the multiple driven toothed plates (503) are connected to the same linkage frame (504). The linkage frame (504) is connected to the screening frame (2).

2. The method for preparing a recycled graphite disc according to claim 1, characterized in that, The bottom of the screening plate (4051) is connected to two adjacent areas with a grading partition (402). The bottom of the screening box (401) is provided with a discharge port (403) corresponding to the grading partition (402). The bottom of the screening box (401) is connected to a funnel bucket (406) corresponding to the discharge port (403), which is used to gather the powder falling through the screening plate (4051) to the discharge port (403).

3. The method for preparing a recycled graphite disc according to claim 2, characterized in that, The bottom of the screening box (401) is connected to a first adapter frame (4041), and a hydraulic cylinder (4042) is rotatably connected to the inner side of the first adapter frame (4041). The other end of the hydraulic cylinder (4042) is rotatably connected to a second adapter frame (4043), and the second adapter frame (4043) is connected to the screening frame (2).

4. The method for preparing a recycled graphite disc according to claim 3, characterized in that, The screening box (401) has a strip-shaped opening (6) on its side end face. An interference component (7) is slidably connected in the strip-shaped opening (6). The interference component (7) includes an interference plate (701) slidably connected in the strip-shaped opening (6). The interference plate (701) is suspended above the screening plate (4051). The bottom of the interference plate (701) has multiple micro-holes. The end of the interference plate (701) is connected to a side support frame (702). The interference plate (701) is connected to the screening frame (2) through the side support frame (702).

5. The method for preparing a recycled graphite disc according to claim 4, characterized in that, The interference component (7) also includes multiple piston cans (703) connected to the screening frame (2). The piston can (703) has a piston hole on its end face. A piston rod (704) is sleeved in the piston hole. A piston disc is connected to the end of the piston rod (704). The piston disc is sleeved in the piston can (703). The other end of the multiple piston rods (704) is connected to the same linkage rod (705). The multiple piston rods (704) are connected to the bottom of the screening box (401) through the same linkage rod (705). The other end of the multiple piston cans (703) is connected through the same pressure diversion pipe (706). The interference plate (701) has a hollow structure inside. The interference plate (701) and the pressure diversion pipe (706) are connected through an air pipe.

6. The method for preparing a recycled graphite disc according to claim 5, characterized in that, The raw materials in the formulation include graphite waste, coal tar pitch and modified phenolic resin. The graphite waste includes waste graphite crucibles, broken graphite electrodes, calcined petroleum coke insulation waste and graphitized dust collection powder.

7. The method for preparing a recycled graphite disc according to claim 6, characterized in that, The kneading is carried out in a kneading pot, and the molding is performed using a vibration molding machine.

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