Waste recycling apparatus

Abstract

The embodiment of the present application discloses a waste recycling device, which comprises a barrel, a heating layer and a stirring component; the barrel comprises a first barrel and a second barrel, the second barrel is connected between the inner top wall and the bottom wall of the first barrel, the barrel is provided with a first feeding port, a first discharging port and a vacuum air outlet, the first feeding port is used for receiving materials, the first discharging port is used for conveying materials outward, and the vacuum air outlet is used for extracting air in the second barrel; the first heating layer is arranged between the first barrel and the second barrel to heat the materials entering the second barrel; the stirring component is arranged on the top of the barrel and can be inserted into the second barrel and rotated relative to the second barrel to stir the materials entering the second barrel. The waste recycling device of the embodiment of the present application provides higher-quality intermediate products for subsequent purification processes, thereby improving the resource utilization rate as a whole.

Description

Technical Field

[0001] This invention relates to the field of crystal waste recycling and treatment technology, and specifically to a waste recycling and treatment device. Background Technology

[0002] Polycrystalline silicon is a key basic material for the photovoltaic and semiconductor industries. As the manufacturing scale of integrated circuits and solar cells continues to expand, the amount of waste generated during wafer dicing (mainly including mono / polycrystalline silicon debris, polyethylene glycol (PEG) dicing fluid, silicon carbide (SiC) abrasives, and trace metal impurities) is increasing. If such waste is not effectively treated, it will not only waste high-purity silicon resources, but may also pose environmental risks due to the presence of organic matter and heavy metals.

[0003] In related technologies, some recycling processes use hot air drying combined with atmospheric pressure melting to process silicon waste. However, the drying stage easily leads to silicon powder oxidation, affecting subsequent purification efficiency. Simultaneously, melting under atmospheric pressure makes it difficult to effectively remove dissolved oxygen, nitrogen, hydrogen, and other gaseous impurities from the molten silicon, limiting the crystal quality and application grade of the recycled silicon. Furthermore, traditional methods have low recovery rates for PEG cutting fluids, and their synergistic removal effect on SiC and metal impurities during the impurity removal process is limited, resulting in an overall resource recovery rate typically below 50% and high energy consumption. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a waste recycling and processing device. The vacuum drying method reduces energy consumption while providing higher quality intermediate products for subsequent purification processes, thereby improving the overall resource utilization rate.

[0006] The waste recycling and processing device of this invention includes a barrel, a heating layer, and a stirring component. The barrel includes a first barrel and a second barrel, with the second barrel connected between the top and bottom walls of the first barrel. The barrel has a first inlet, a first outlet, and a vacuum extraction port. The first inlet is used to receive materials, the first outlet is used to convey materials outward, and the vacuum extraction port is used to extract air from the second barrel. The first heating layer is disposed between the first barrel and the second barrel to heat the materials introduced into the second barrel. The stirring component passes through the top of the barrel and can extend into the second barrel and is rotatable relative to the second barrel to stir the materials introduced into the second barrel.

[0007] This invention employs a double-layer barrel structure, with the second barrel positioned inside the first barrel to form a sealed processing space. A vacuum extraction port draws air from the second barrel to create a low-pressure environment, while a heating layer uniformly heats the material between the two barrels. A stirring component penetrates from the top of the barrel and rotates continuously, ensuring thorough agitation of the material under vacuum and heating conditions. The vacuum environment effectively suppresses contact between silicon powder and oxygen, fundamentally solving the oxidation problem caused by traditional hot air drying. The stirring component increases the heated surface area of ​​the material, significantly improving the evaporation efficiency of volatile components such as PEG. Simultaneously, uniform heat conduction prevents localized overheating or adhesion of the material. This vacuum drying method reduces energy consumption while providing higher-quality intermediate products for subsequent purification processes, thereby improving the overall resource utilization rate.

[0008] In some embodiments, the stirring component of the present invention includes a central stirring shaft and rake teeth. The central stirring shaft passes through the top of the barrel along the axial direction of the barrel body, and a portion of the central stirring shaft can extend into the second barrel body. The central stirring shaft is rotatable relative to the barrel body. The rake teeth are spirally arranged on the central stirring shaft, and there are guide grooves between adjacent rake teeth.

[0009] In some embodiments, the present invention further includes a magnetic fluid seal, which is disposed at the connection between the stirring component and the barrel.

[0010] In some embodiments, the present invention further includes a closed feeding assembly, which is connected to the barrel to receive and convey materials into the barrel. The closed feeding assembly includes a feeding hopper, a screw conveyor, a nitrogen replacement chamber, and an upstream sealing valve. The feeding hopper, the screw conveyor, and the nitrogen replacement chamber are connected sequentially from top to bottom. The screw conveyor is used to rotate and convey materials into the nitrogen replacement chamber. The top of the nitrogen replacement chamber has a nitrogen inlet and a nitrogen outlet. The nitrogen inlet is used to introduce nitrogen into the nitrogen replacement chamber, and the nitrogen outlet is used to discharge waste gas from the nitrogen replacement chamber. The upstream sealing valve is located in the nitrogen replacement chamber to control the flow of materials within the nitrogen replacement chamber.

[0011] In some embodiments of the present invention, the closed feed assembly further includes a downstream sealing valve, which is disposed in the nitrogen replacement chamber and located downstream of the upstream sealing valve, and a buffer compartment can be formed between the downstream sealing valve and the upstream sealing valve in the nitrogen replacement chamber.

[0012] In some embodiments, the present invention further includes an airflow sorting assembly, which is connected to the barrel to receive heated waste particles. The airflow sorting assembly includes a horizontal sorting chamber, a centrifugal fan, a cyclone separator, and a fine powder collection hopper. The horizontal sorting chamber is connected to the barrel to receive heated waste particles. The centrifugal fan is disposed in the horizontal sorting chamber to form an airflow within the horizontal sorting chamber. The cyclone separator is disposed outside the horizontal sorting chamber, with a portion of the cyclone separator extending into the horizontal sorting chamber to capture fine particles carried in the airflow. The fine powder collection hopper is disposed at the outlet of the cyclone separator to receive the captured fine particles.

[0013] In some embodiments, the airflow sorting assembly of the present invention further includes a slide rail and a particle size adjustment baffle. The slide rail is disposed vertically within the horizontal sorting chamber, and the particle size adjustment baffle is disposed on the slide rail and is movable relative to the slide rail in the vertical direction to change the cross-sectional area of ​​the airflow channel.

[0014] In some embodiments, the present invention further includes an acid washing reaction tank, a stirring motor, an output shaft, stirring blades, a rinsing tank, several overflow baffles, and a vacuum filtration plate. The acid washing reaction tank is located downstream of and communicates with the horizontal sorting chamber to receive materials. The inner wall of the acid washing reaction tank has a polytetrafluoroethylene lining layer, and the bottom of the acid washing reaction tank has a discharge port. The stirring motor is located in the acid washing reaction tank. The output shaft passes through the top of the acid washing reaction tank and rotates coaxially with the output end of the stirring motor. The stirring blades are located on the output shaft. The rinsing tank can communicate with the acid washing reaction tank through the discharge port. Several overflow baffles are located at the bottom of the rinsing tank, and the height of the several overflow baffles decreases sequentially from the liquid inlet end to the liquid outlet end. The vacuum filtration plate passes through the rinsing tank.

[0015] In some embodiments, the present invention further includes a smelting furnace, which is connected to the rinsing tank to receive materials. The smelting furnace includes a furnace shell, an induction coil, a cooling tray, a graphite crucible, an electromagnetic stirring coil, an observation window, an infrared temperature measuring hole, and a vacuum assembly. The furnace shell is connected to the rinsing tank to receive materials. The furnace shell includes a first furnace shell and a second furnace shell, with the second furnace shell located inside the first furnace shell. The induction coil is wound around the second furnace shell to heat it. The cooling tray is located at the bottom of the second furnace shell and can be raised and lowered vertically relative to the furnace shell. The graphite crucible is located inside the second furnace shell. The electromagnetic stirring coil is located at the bottom of the graphite crucible. The observation window and the infrared temperature measuring hole are both located in the first furnace shell. A portion of the vacuum assembly passes through the top of the furnace shell and can extend into the second furnace shell.

[0016] In some embodiments, the present invention further includes a directional solidification cavity, an upper heating belt, a lower heating belt, and a graphite support, wherein the directional solidification cavity is located below the melting furnace; the upper heating belt and the lower heating belt are both located within the directional solidification cavity; and the graphite support is located within the directional solidification cavity. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the structure of the sealed feeding assembly according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the drying component according to an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the airflow sorting component according to an embodiment of the present invention.

[0021] Figure 5 This is a schematic diagram of the acid washing reaction vessel according to an embodiment of the present invention.

[0022] Figure 6 This is a schematic diagram of the structure of the smelting furnace according to an embodiment of the present invention.

[0023] Figure 7 This is a schematic diagram of the structure of the directional solidification cavity according to an embodiment of the present invention.

[0024] Figure label:

[0025] 100. Waste recycling and processing equipment; 1. Barrel body; 101. First barrel body; 102. Second barrel body; 103. First feed inlet; 104. First discharge outlet; 105. Vacuum extraction port; 2. Heating layer; 3. Stirring components; 301. Central stirring shaft; 302. Rake teeth; 4. Magnetic fluid seal; 5. Sealed feeding assembly; 501. Feed hopper; 502. Screw conveyor; 503. Nitrogen replacement chamber; 5031. Nitrogen inlet; 5032. Nitrogen exhaust port; 504. Upstream sealing valve; 505. Downstream sealing valve; 6. Airflow sorting assembly; 601. Horizontal sorting chamber; 602. Centrifugal fan; 603. Cyclone separator; 604. Fine powder collection hopper; 605. 1. Slide rail; 606. Particle size adjustment baffle; 7. Pickling reaction vessel; 701. Polytetrafluoroethylene lining; 8. Stirring motor; 9. Output shaft; 10. Stirring blades; 11. Rinse tank; 12. Overflow baffle; 13. Vacuum filter plate; 14. Melting furnace; 1401. Furnace shell; 14011. First furnace shell; 14012. Second furnace shell; 1402. Induction coil; 1403. Cooling tray; 1404. Graphite crucible; 1405. Electromagnetic stirring coil; 1406. Observation window; 1407. Infrared temperature measuring hole; 1408. Vacuum assembly; 15. Directional solidification chamber; 16. Upper heating belt; 17. Lower heating belt; 18. Graphite support base. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] Reference Figures 1-7 The waste recycling and processing device 100 of this invention includes a barrel 1, a heating layer 2, and a stirring component 3. The barrel 1 includes a first barrel 101 and a second barrel 102. The second barrel 102 is connected between the top wall and the bottom wall of the first barrel 101. The barrel 1 has a first inlet 103, a first outlet 104, and a vacuum extraction port 105. The first inlet 103 is used to receive materials, the first outlet 104 is used to convey materials outward, and the vacuum extraction port 105 is used to extract air from the second barrel 102. The heating layer 2 is disposed between the first barrel 101 and the second barrel 102 to heat the materials introduced into the second barrel 102. The stirring component 3 is disposed at the top of the barrel 1 and can extend into the second barrel 102 and is rotatable relative to the second barrel 102 to stir the materials introduced into the second barrel 102.

[0028] This invention employs a double-layer barrel structure 1, with a second barrel 102 positioned inside the first barrel 101 to form a sealed processing space. A vacuum extraction port 105 draws air from the second barrel 102 to establish a low-pressure environment, while a heating layer 2 uniformly heats the material between the two barrel layers. A stirring component 3 penetrates from the top of the barrel 1 and rotates continuously, ensuring thorough agitation of the material under vacuum and heating conditions. The vacuum environment effectively suppresses contact between silicon powder and oxygen, fundamentally solving the oxidation problem caused by traditional hot air drying. The stirring component 3 increases the heated surface area of ​​the material, significantly improving the evaporation efficiency of volatile components such as PEG. Simultaneously, uniform heat conduction prevents localized overheating or adhesion of the material. This vacuum drying method reduces energy consumption while providing higher-quality intermediate products for subsequent purification processes, thereby improving the overall resource utilization rate.

[0029] In some specific embodiments, internally controllable heat-conducting oil is introduced between the first barrel 101 and the second barrel 102 to uniformly heat the inside of the cavity.

[0030] In some embodiments, such as Figure 1 and Figure 3 As shown, the stirring component 3 of this embodiment includes a central stirring shaft 301 and rake teeth 302. The central stirring shaft 301 passes through the top of the barrel 1 along the axial direction of the barrel 1, and a portion of the central stirring shaft 301 can extend into the second barrel 102. The central stirring shaft 301 is rotatable relative to the barrel 1. The rake teeth 302 are spirally arranged on the central stirring shaft 301, and there are guide grooves between adjacent rake teeth 302.

[0031] In this embodiment of the invention, the stirring component 3 drives the spiral rake teeth 302 to rotate uniformly within the second barrel 102 via the central stirring shaft 301. The spiral structure of the rake teeth 302, in conjunction with the guide channel, forms a continuous propulsion channel. This design enables the material to achieve three-dimensional motion under vacuum heating. The spiral rake teeth 302 axially transport the material from the feed end to the discharge end, and the guide channel enhances the radial diffusion capability of the material. This motion significantly increases the contact area between the material and the heated wall surface, and the guide channel guides the airflow evenly through the material layer. The stirring component 3 achieves rapid and uniform drying by optimizing the material movement trajectory, while reducing energy consumption and preventing material agglomeration.

[0032] In some specific embodiments, a vacuum extraction port 105 is provided at the top of the barrel 1, which is connected to a separate vacuum unit to maintain the pressure inside the chamber below 100 Pa during the drying process.

[0033] During the drying stage, the system activates the vacuum unit to evacuate to the set pressure, while the heat transfer oil is heated to 120–150°C. The central stirring shaft 30120 rotates at 5–10 rpm, causing the waste material to be continuously agitated and come into contact with the hot wall under the action of the rake teeth 302. The residual PEG cutting fluid evaporates under vacuum and low temperature conditions and is discharged through the vacuum extraction port 105. After condensation and recovery, a high PEG recovery rate can be achieved. After drying is completed, the vacuum unit is turned off, and the dried material falls into the airflow sorting component 6 by gravity.

[0034] In some embodiments, such as Figure 4 As shown, this embodiment of the invention also includes a magnetic fluid seal 4, which is disposed at the connection between the stirring component 3 and the tank body 1. This seal utilizes a magnetic field to confine the liquid magnetic fluid, forming an isolation barrier, while its sealing structure allows the central stirring shaft 301 to rotate freely. This design effectively prevents external air from seeping into the tank body 1, while also preventing internal volatile gases from leaking outwards.

[0035] In some embodiments, such as Figure 1 and Figure 2 As shown, this embodiment of the invention also includes a closed feeding assembly 5, which is connected to the barrel 1 to receive and convey materials into the barrel 1. The closed feeding assembly 5 includes a feeding hopper 501, a screw conveyor 502, a nitrogen replacement chamber 503, and an upstream sealing valve 504. The feeding hopper 501, the screw conveyor 502, and the nitrogen replacement chamber 503 are connected sequentially from top to bottom. The screw conveyor 502 is used to rotate and convey materials into the nitrogen replacement chamber 503. The top of the nitrogen replacement chamber 503 has a nitrogen inlet 5031 and a nitrogen outlet 5032. The nitrogen inlet 5031 is used to introduce nitrogen into the nitrogen replacement chamber 503, and the nitrogen outlet 5032 is used to discharge waste gas from the nitrogen replacement chamber 503. The upstream sealing valve 504 is located in the nitrogen replacement chamber 503 to control the flow of materials within the nitrogen replacement chamber 503.

[0036] The sealed feeding assembly 5 of this invention constructs a continuous feeding system through a feed hopper 501, a screw conveyor 502, and a nitrogen replacement chamber 503 connected in series. The screw conveyor 502 pushes the material into the nitrogen replacement chamber 503 in a rotating manner, and an upstream sealing valve 504 controls the flow of the material within the replacement chamber. A high-purity nitrogen inlet 5031 continuously supplies air into the replacement chamber and can also discharge waste gas from the waste material. A nitrogen exhaust port 5032 simultaneously discharges oxygen-containing waste gas. This assembly enables the material to be transported under an inert atmosphere, and its sealed structure prevents external air from entering the system. The nitrogen replacement process effectively reduces the risk of material oxidation, and the screw conveyor ensures continuous and stable feeding. This design maintains the integrity of the vacuum environment in subsequent drying processes, significantly improving the quality of raw material processing and reducing the introduction of impurities.

[0037] In some embodiments, such as Figure 1 and Figure 2 As shown, the closed feed assembly 5 of this embodiment of the invention also includes a downstream sealing valve 505. The downstream sealing valve 505 is disposed in the nitrogen replacement chamber 503 and is located downstream of the upstream sealing valve 504. A buffer compartment can be formed between the downstream sealing valve 505 and the upstream sealing valve 504 in the nitrogen replacement chamber 503.

[0038] In this embodiment of the invention, the sealed feeding assembly 5, by adding a downstream sealing valve 505, forms a closed buffer compartment together with the upstream sealing valve 504 within the nitrogen replacement chamber 503. After the material enters this compartment through the upstream valve, the upstream valve closes, and the system introduces inert gas through the nitrogen inlet 5031 and discharges the original air through the exhaust port, completing the atmosphere replacement. Subsequently, the downstream valve opens, and the material enters the subsequent process under the protection of the inert atmosphere. This dual-valve buffer compartment design achieves atmosphere isolation between the feeding process and the main system, and its closed replacement space ensures that oxygen is completely removed. This structure significantly reduces the risk of oxygen being introduced due to the feeding operation and effectively maintains the low-oxygen environment of the drying chamber.

[0039] In some embodiments, such as Figure 1 and Figure 4 As shown, this embodiment of the invention also includes an airflow sorting component 6, which is connected to the barrel 1 to receive heated waste particles. The airflow sorting component 6 includes a horizontal sorting chamber 601, a centrifugal fan 602, a cyclone separator 603, and a fine powder collection hopper 604. The horizontal sorting chamber 601 is connected to the barrel 1 to receive heated waste particles. The centrifugal fan 602 is located in the horizontal sorting chamber 601 to form an airflow inside the horizontal sorting chamber 601. The cyclone separator 603 is located outside the horizontal sorting chamber 601, and part of the cyclone separator 603 extends into the horizontal sorting chamber 601 to capture fine particles carried in the airflow. The fine powder collection hopper 604 is located at the outlet of the cyclone separator 603 to receive the captured fine particles.

[0040] In this embodiment of the invention, the airflow separation component 6 receives dried waste particles through a horizontal separation chamber 601, and a centrifugal fan 602 generates a stable horizontal airflow within the separation chamber. This airflow achieves preliminary separation based on differences in particle size and density, with the lighter, finer silicon powder entering the cyclone separator 603 with the airflow. The cyclone separator 603 uses a centrifugal force field to capture the fine particles in the airflow, and a fine powder collection hopper 604 receives and stores the separated high-purity silicon powder. The airflow separation process significantly improves the silicon powder recovery rate, and the cyclone separator ensures efficient collection of fine particles, providing a high-quality raw material base for subsequent acid washing processes.

[0041] In some embodiments, such as Figure 1 and Figure 4As shown, the airflow sorting component 6 of this embodiment of the invention also includes a slide rail 605 and a particle size adjustment baffle 606. The slide rail 605 is disposed vertically in the horizontal sorting cavity 601, and the particle size adjustment baffle 606 is disposed on the slide rail 605 and is movable relative to the slide rail 605 in the vertical direction to change the cross-sectional area of ​​the airflow channel.

[0042] In this embodiment of the invention, the airflow sorting component 6 is vertically mounted with a particle size adjustment baffle 606 within the horizontal sorting chamber 601 via a slide rail 605. This baffle can move up and down along the slide rail 605 to precisely adjust the effective cross-sectional area of ​​the airflow channel and thus the sorting particle size threshold. Operators control the airflow speed and distribution by changing the baffle position. This adjustment mechanism allows the system to adapt to materials with different particle size distributions, and the adjustable structure optimizes sorting accuracy and efficiency. The particle size adjustment function significantly improves the equipment's adaptability to different materials, and precise control ensures the quality of fine silicon powder recovery, providing a stable raw material guarantee for subsequent processes.

[0043] In some embodiments, such as Figure 1 He Ru Figure 5 As shown, embodiments of the present invention also include an acid washing reaction tank 7, a stirring motor 8, an output shaft 9, stirring blades 10, a rinsing tank 11, several overflow baffles 12, and a vacuum filtration plate 13. The acid washing reaction tank 7 is located downstream of and communicates with the horizontal sorting chamber 601 to receive materials. The inner wall of the acid washing reaction tank 7 has a polytetrafluoroethylene lining layer 701, and the bottom of the acid washing reaction tank 7 has a discharge port. The stirring motor 8 is located in the acid washing reaction tank 7. The output shaft 9 passes through the top of the acid washing reaction tank 7 and rotates coaxially with the output end of the stirring motor 8. The stirring blades 10 are located on the output shaft 9. The rinsing tank 11 can communicate with the acid washing reaction tank 7 through the discharge port. Several overflow baffles 12 are located at the bottom of the rinsing tank 11, and the height of the several overflow baffles 12 decreases sequentially from the liquid inlet end to the liquid outlet end. The vacuum filtration plate 13 passes through the rinsing tank 11.

[0044] In this embodiment of the invention, the pickling system receives sorted silicon powder through a pickling reaction tank 7, with a polytetrafluoroethylene liner 701 providing excellent corrosion resistance. A stirring motor 8 drives an output shaft 9 to rotate the stirring blades 10, ensuring thorough contact and reaction between the mixed acid solution and the silicon powder. After the reaction is complete, the material enters a rinsing tank 11 through a bottom discharge port, where several overflow baffles 12 of decreasing height form a stepped water flow path.

[0045] The vacuum filter plate 13 efficiently dehydrates the rinsed silicon powder, and its negative pressure suction significantly reduces the moisture content of the material. This integrated system enables continuous operation of the acid washing and rinsing dehydration processes. The polytetrafluoroethylene lining ensures that the equipment can withstand strong acid environments, the stepped overflow design improves rinsing efficiency, and the vacuum filter device reduces residual moisture. The entire process effectively removes metal impurities and ensures the cleanliness of the silicon powder.

[0046] In some specific embodiments, during pickling, a mixed acid solution with a ratio of HF:HNO3:H2O = 3:1:6 is first added to the pickling reaction tank 7. The stirring motor 8 is then turned on, with the speed controlled at 60–80 rpm, the reaction temperature maintained at 30–40°C, and the reaction time at 2–3 hours to dissolve metallic impurities and some silicon oxide. After the reaction is completed, the drain port is opened, and the waste acid solution is discharged into the waste liquid treatment system via an acid-resistant pump, while the solid residue remains in the tank. Subsequently, ultrapure water is injected for three rinsings. After each rinsing, the solution is filtered through the vacuum filter plate 13, and the filtrate overflows through the overflow baffle 12 in stages to ensure thorough rinsing. Finally, the clean silicon powder is sent to the vacuum induction melting furnace 14 through the bottom outlet of the ultrapure water rinsing tank 11.

[0047] In some embodiments, such as Figure 1 and Figure 6 As shown, embodiments of the present invention also include a smelting furnace 14, which is connected to a rinsing tank to receive materials. The smelting furnace 14 includes a furnace shell 1401, an induction coil 1402, a cooling tray 1403, a graphite crucible 1404, an electromagnetic stirring coil 1405, an observation window 1406, an infrared temperature measuring port 1407, and a vacuum assembly 1408. The furnace shell 1401 is connected to the rinsing tank to receive materials. The furnace shell 1401 includes a first furnace shell 14011 and a second furnace shell 14012, with the second furnace shell 14012 located inside the first furnace shell 14011. The induction coil 1402 is wound around the second furnace shell 14012 to heat it. The cooling tray 1403 is located at the bottom of the second furnace shell 14012 and can be raised and lowered vertically relative to the furnace shell 1401. The graphite crucible 1404 is located inside the second furnace shell 14012. An electromagnetic stirring coil 1405 is located at the bottom of the graphite crucible 1404. An observation window 1406 and an infrared temperature measuring hole 1407 are both located in the first furnace shell 14011. A portion of the vacuum assembly 1408 passes through the top of the furnace shell 1401 and can extend into the second furnace shell 14012.

[0048] The melting furnace 14 creates a sealed melting environment through a double-layer furnace shell 1401 structure. An induction coil 1402, wound around the inner furnace shell 1401, generates an alternating magnetic field to heat the graphite crucible 1404. An electromagnetic stirring coil 1405 generates a rotating magnetic field at the bottom of the crucible to drive melt convection. A vacuum assembly 1408 maintains a high vacuum within the furnace to remove gaseous impurities. Operators monitor the melting process through an observation window 1406, while an infrared temperature sensor 1407 monitors the melt temperature in real time. The cooling tray 1403 achieves directional solidification through precise control of its lifting speed, and its adjustable displacement mechanism optimizes crystal growth conditions. This integrated system achieves efficient melting of silicon under vacuum conditions. Electromagnetic stirring promotes melt homogenization and impurity volatilization, while controllable cooling ensures orderly crystal growth. The entire system significantly improves the purity and crystal quality of polycrystalline silicon.

[0049] In some specific embodiments, the inner wall of the furnace shell 1401 is lined with a high-purity alumina insulation layer. The induction coil 140243 is made of hollow copper tube, wound around the outside of the insulation layer, and connected to a medium-frequency power supply (frequency 1–10kHz, power 50–200kW) through a copper busbar.

[0050] A graphite crucible 1404 is placed at the center of the furnace shell 1401. Its inner wall is uniformly coated with a 50–80 μm thick silicon nitride layer to prevent the molten silicon from reacting with the graphite to form silicon carbide. An electromagnetic stirring coil 1405 is embedded in the bottom of the graphite crucible 1404 to apply an alternating magnetic field during the melting process, promoting melt homogenization. The vacuum system consists of a mechanical pump, a Roots pump, and a diffusion pump connected in series. These are connected to the evacuation flange at the top of the furnace shell 1401 via vacuum pipes, allowing the furnace to be evacuated to a vacuum level of 10. - The furnace shell 140142 has a quartz glass observation window 1406 and an infrared temperature measuring hole 1407 on its side wall for real-time monitoring of the melting status and temperature.

[0051] In some embodiments, such as Figure 1 and Figure 7 As shown, embodiments of the present invention further include a directional solidification chamber 15, an upper heating belt 16, a lower heating belt 17, and a graphite support 18. The directional solidification chamber 15 is located below the melting furnace 14. Both the upper heating belt 16 and the lower heating belt 17 are located within the directional solidification chamber 15. The graphite support 18 is located within the directional solidification chamber 15.

[0052] The directional solidification system of this invention receives molten silicon in a directional solidification chamber 15. An upper heating band 16 within the chamber maintains the temperature of the upper part of the molten silicon above its melting point, while a lower heating band 17 forms a precisely controlled temperature gradient along the axial direction. A graphite support 18 supports the silicon ingot during solidification, and its stable support structure ensures smooth progress at the solid-liquid interface. This system utilizes the temperature gradient to drive directional crystal growth; the upper heating band 16 prevents premature solidification, and the lower heating band 17 promotes preferential crystallization at the bottom. Graphite provides excellent thermal conductivity and chemical stability, and the directional solidification process effectively promotes impurity accumulation towards the top. This design significantly improves the crystallization quality of polycrystalline silicon, and the temperature gradient control optimizes impurity segregation, ultimately yielding a regenerated silicon ingot with high dislocation density and high purity.

[0053] In some specific embodiments, the upper heating band 16 maintains a constant temperature of 1420°C, while the lower heating band 17 cools down along the axial gradient at a rate of 10°C / cm. A graphite support 18 is provided at the bottom of the directional solidification chamber 15, and a positioning pin is provided at the top of the graphite support 18, which engages with the corresponding hole at the bottom of the cooling tray 140350 to ensure that the molten silicon is transferred without disturbance from the graphite crucible 1404 to the graphite support 18.

[0054] In the actual operation of the enterprise handling approximately 5 tons of wafer dicing waste per day, the entire production line is first tested for airtightness before system startup to confirm that the connecting flanges and vacuum isolation valves between the sealed feeding assembly 5, barrel 1, pickling reaction tank 7, melting furnace 14, and directional solidification chamber 15 are properly sealed. Subsequently, wet waste with a moisture content of approximately 12%, a silicon powder particle size distribution of 1–50 μm, a SiC content of 8–12 wt%, a total amount of metallic impurities (Fe, Cr, Ni, etc.) of approximately 200 ppm, and a residual PEG cutting fluid of approximately 5 wt% is fed into the feeding hopper 501. After the waste material is pushed into the buffer compartment of the nitrogen replacement chamber 503 by the screw feeder, the upstream sealing valve 504 is closed, and high-purity nitrogen is introduced from the nitrogen inlet at a pressure of 0.3 MPa. After 30 seconds, the exhaust port is opened to release the gas. This process is repeated three times to reduce the oxygen content in the buffer compartment to <10 ppm. Subsequently, the downstream rotary sealing door is opened, and the material enters the vacuum rake drying chamber under an inert atmosphere, effectively avoiding the oxidation of silicon surfaces and the formation of a SiO2 layer caused by oxygen contact in traditional hot air drying. After entering the vacuum rake drying chamber, the vacuum unit draws the pressure inside the barrel 1 to 80 Pa through the vacuum extraction port 105. At the same time, the heat transfer oil in the jacket heating layer 2 is heated to 135°C, and the central stirring shaft 301 drives the scraper rake teeth 302 to slowly turn the material at a speed of 8 rpm. Because the inner wall of barrel 1 is mirror-polished (Ra≤0.4μm), the material does not easily adhere, and the guide channel guides the material to advance evenly along the axial direction, allowing PEG to rapidly vaporize at 135℃ and 80Pa (its boiling point is below 100℃ under this vacuum). The vapor enters the condensation recovery device through the vacuum extraction port 105, with a condensation efficiency of over 92%, achieving efficient resource recovery of PEG. After drying, the material has a moisture content of <0.5%, and XPS detection shows that the SiO2 content on the silicon surface is <0.8at%, significantly better than the >3at% after drying with atmospheric pressure hot air. The dried material falls into the horizontal sorting chamber 601 of the airflow sorting component 6. After the centrifugal fan 602 is started, a horizontal airflow field of 20m / s is established in the horizontal sorting chamber 601. At this point, silicon powder with a density of 2.33 g / cm³ and a particle size <20 μm is carried by the airflow to the inlet of the cyclone separator 603. Meanwhile, SiC particles with a density of 3.21 g / cm³ and denser metallic impurities, due to their higher Stokes numbers, settle to the bottom of the horizontal sorting chamber 601 under inertia and are discharged through the side outlet. Adjusting the height of the particle size adjusting baffle 606 via the slide rail 605 changes the cross-sectional area of ​​the airflow channel, thereby precisely controlling the critical particle size for sorting. For example, when the baffle is lowered to 15 cm from the bottom of the chamber, only particles <15 μm are carried into the cyclone separator 603, achieving efficient physical separation of silicon powder from coarse impurities, with a silicon powder recovery rate of 95% and a SiC removal rate >90%. The sorted fine silicon powder falls into the fine powder collection hopper 604 and then enters the acid washing reaction tank 7 through a sealed hose. At this point, a mixed acid solution of HF:HNO3:H2O = 3:1:6 is injected through the acid addition port, with a liquid-to-solid ratio of 5:1.A motor drives a three-layer paddle stirrer 37 to rotate at 70 rpm. The blades, installed at a 45° angle, form an upper and lower circulating flow field, ensuring that the acid solution fully contacts the particle surface. HF preferentially dissolves metal oxides and some SiO2, while HNO3 passivates the silicon surface and inhibits excessive corrosion. After 2.5 hours of reaction, ICP-MS analysis shows that the concentrations of metal impurities such as Fe, Cr, and Ni have decreased to <5 ppm. The waste acid is pumped to the waste liquid treatment system via the drain port 38, and then ultrapure water is injected for three rinsings. After each rinsing, a vacuum filter plate 1341 applies a negative pressure of -80 kPa to reduce the moisture content of the filter cake to below 15%. At the same time, the three-layer overflow baffle 1240 forms a stepped overflow path to ensure that the rinsing water is refreshed step by step, avoiding cross-contamination, and ultimately the residual fluoride ions on the silicon powder surface are <1 ppm. The clean silicon powder is then fed into the graphite crucible 1404 of the vacuum induction melting furnace 14. After the feed port is closed, the vacuum system 47 is started, and the furnace pressure is reduced to 5×10 through three stages of pumping by mechanical pump, Roots pump and diffusion pump. -²Pa. At this point, the intermediate frequency power supply is activated, and the induction coil 1402 completely melts the silicon powder at a temperature above 1420℃. Due to the high vacuum state inside the furnace, the partial pressure of gaseous impurities such as H2, O2, and N2 dissolved in the silicon melt is much higher than the ambient pressure. According to Henry's Law, the gas rapidly escapes from the melt. Simultaneously, the electromagnetic stirring coil 140546 at the bottom of the graphite crucible 140444 applies a low-frequency alternating magnetic field (frequency 0.5–2 Hz), inducing forced convection inside the melt, breaking the boundary layer, accelerating the bubble rising rate, and reducing the total gas content in the melt to <1 ppm. In addition, the silicon nitride coating effectively prevents direct contact between the molten silicon and the graphite crucible 1404, preventing the Si+ C→SiC side reaction and avoiding the introduction of new carbon impurities. After melting is completed, the cooling tray 1403 descends at a uniform speed of 4 mm / h under the drive of the servo motor, allowing the graphite crucible 1404 to precisely align with the graphite support 18 in the directional solidification chamber 15 through positioning pins. After the molten silicon flows into the directional solidification chamber 15, the upper heating zone 16 maintains a temperature of 1420℃, while the lower heating zone 1753 cools down at a gradient of 10℃ / cm, forming a stable axial temperature gradient. Under these conditions, the silicon solidifies directionally from the bottom up. According to the segregation principle with an equilibrium distribution coefficient k < 1, residual metallic impurities (such as Fe and Al) and incompletely removed SiC particles are repelled to the solid-liquid interface front and accumulate at the top of the ingot as the solidification front moves upward. The resulting polycrystalline silicon ingot has a resistivity > 2000 Ω·cm at the bottom and a minority carrier lifetime > 10 μs, meeting the photovoltaic-grade polycrystalline silicon standard (GB / T25074-2017), with some batches even reaching the primary requirements for semiconductor-grade electronic-grade silicon. The entire process operates continuously in a fully enclosed, inert, or vacuum environment. Each unit is isolated by pressure zones and atmospheres through a first, second, and third vacuum isolation valve, ensuring optimal process conditions for each step and avoiding cross-contamination. In actual operation, the system achieves a resource utilization rate of over 85% and reduces energy consumption by about 30% compared to the traditional atmospheric pressure smelting process. This fully demonstrates the comprehensive advantages of the invention in solving technical problems such as silicon powder oxidation, residual gaseous impurities, low PEG recovery rate, and poor efficiency of SiC and metal synergistic removal.

[0055] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0057] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0059] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0060] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A waste recycling and processing device, characterized in that, include: The container includes a barrel body (1), a heating layer (2), and a stirring component (3). The barrel body (1) comprises a first barrel body (101) and a second barrel body (102). The second barrel body (102) is connected between the top and bottom walls of the first barrel body (101). The barrel body (1) has a first feed inlet (103), a first discharge outlet (104), and a vacuum extraction port (105). The first feed inlet (103) is used to receive materials, and the first discharge outlet (104) is used to convey materials outward. The vacuum extraction port (105) is used to extract air from the second barrel (102). The heating layer (2) is disposed between the first barrel (101) and the second barrel (102) to heat the material introduced into the second barrel (102). The stirring component (3) is disposed on the top of the barrel (1) and can extend into the second barrel (102) and can rotate relative to the second barrel (102) to stir the material introduced into the second barrel (102).

2. The waste recycling and processing device according to claim 1, characterized in that, The stirring component (3) includes a central stirring shaft (301) and rake teeth (302). The central stirring shaft (301) passes through the top of the barrel (1) along the axial direction of the barrel (1), and a portion of the central stirring shaft (301) can extend into the second barrel (102). The central stirring shaft (301) is rotatable relative to the barrel (1). The rake teeth (302) are spirally arranged on the central stirring shaft (301), and there are guide grooves between adjacent rake teeth (302).

3. The waste recycling and processing device according to claim 1, characterized in that, It also includes a magnetic fluid seal (4), which is located at the connection between the stirring component (3) and the barrel (1).

4. The waste recycling and processing device according to claim 1, characterized in that, It also includes a closed feeding assembly (5), which is connected to the barrel (1) to receive materials and can convey materials into the barrel (1). The closed feeding assembly (5) includes a feeding hopper (501), a screw conveyor (502), a nitrogen replacement chamber (503), and an upstream sealing valve (504). The feeding hopper (501), the screw conveyor (502), and the nitrogen replacement chamber (503) are connected sequentially from top to bottom. The screw conveyor (502) is used for rotary conveying. The nitrogen gas is introduced into the nitrogen replacement chamber (503). The top of the nitrogen replacement chamber (503) has a nitrogen inlet (5031) and a nitrogen exhaust port (5032). The nitrogen inlet (5031) is used to introduce nitrogen into the nitrogen replacement chamber (503), and the nitrogen exhaust port (5032) is used to discharge the waste gas in the nitrogen replacement chamber (503). The upstream sealing valve (504) is located in the nitrogen replacement chamber (503) to control the flow of materials in the nitrogen replacement chamber (503).

5. The waste recycling and processing device according to claim 4, characterized in that, The closed feed assembly (5) also includes a downstream sealing valve (505), which is located in the nitrogen replacement chamber (503) and downstream of the upstream sealing valve (504). A buffer compartment can be formed between the downstream sealing valve (505) and the upstream sealing valve (504) in the nitrogen replacement chamber (503).

6. The waste recycling and processing apparatus according to any one of claims 1-5, characterized in that, It also includes an airflow sorting assembly (6), which is connected to the barrel (1) to receive heated waste particles. The airflow sorting assembly (6) includes a horizontal sorting chamber (601), a centrifugal fan (602), a cyclone separator (603), and a fine powder collection hopper (604). The horizontal sorting chamber (601) is connected to the barrel (1) to receive heated waste particles. The centrifugal fan (602) is located in the horizontal sorting chamber (601) to form an airflow in the horizontal sorting chamber (601). The cyclone separator (603) is located outside the horizontal sorting chamber (601), and part of the cyclone separator (603) extends into the horizontal sorting chamber (601) to capture fine particles carried in the airflow. The fine powder collection hopper (604) is located at the outlet of the cyclone separator (603) to receive the captured fine particles.

7. The waste recycling and processing device according to claim 6, characterized in that, The airflow sorting component (6) further includes a slide rail (605) and a particle size adjustment baffle (606). The slide rail (605) is arranged vertically in the horizontal sorting chamber (601). The particle size adjustment baffle (606) is arranged on the slide rail (605) and is movable vertically relative to the slide rail (605) to change the cross-sectional area of ​​the airflow channel.

8. The waste recycling and processing device according to claim 6, characterized in that, Also includes: Pickling reaction tank (7), the pickling reaction tank (7) is located downstream of the horizontal sorting chamber (601) and communicates with the horizontal sorting chamber (601) to receive materials, the inner wall of the pickling reaction tank (7) has a polytetrafluoroethylene inner lining layer (701), and the bottom of the pickling reaction tank (7) has a discharge port. Stirring motor (8), the stirring motor (8) is located in the pickling reaction tank (7); Output shaft (9), the output shaft (9) passes through the top of the pickling reaction tank (7) and rotates coaxially with the output end of the stirring motor (8); Stirring blade (10), the stirring blade (10) is disposed on the output shaft (9); A rinsing tank (11) is connected to the pickling reaction tank (7) through the discharge port; A plurality of overflow baffles (12) are provided at the bottom of the rinsing tank (11), and the height of the plurality of overflow baffles (12) decreases sequentially from the liquid inlet end to the liquid outlet end. Vacuum filter plate (13) is inserted through the rinsing tank (11).

9. The waste recycling and processing device according to claim 8, characterized in that, It also includes a smelting furnace (14), which is connected to the rinsing tank to receive materials, the smelting furnace (14) comprising: A furnace shell (1401) is connected to the rinsing tank to receive materials. The furnace shell (1401) includes a first furnace shell (14011) and a second furnace shell (14012), with the second furnace shell (14012) located inside the first furnace shell (14011). An induction coil (1402) is wound around the second furnace shell (14012) to heat the second furnace shell (14012). Cooling tray (1403) is located at the bottom of the second furnace shell (14012) and can be raised and lowered vertically relative to the furnace shell (1401). A graphite crucible (1404) is disposed inside the second furnace shell (14012); An electromagnetic stirring coil (1405) is disposed at the bottom of the graphite crucible (1404); An observation window (1406) and an infrared temperature measuring hole (1407) are provided on the first furnace shell (14011). Vacuum assembly (1408), a portion of which passes through the top of the furnace shell (1401) and can extend into the second furnace shell (14012).

10. The waste recycling and processing device according to claim 9, characterized in that, Also includes: Directional solidification chamber (15), the directional solidification chamber (15) is located below the smelting furnace (14); The upper heating band (16) and the lower heating band (17) are both located inside the directional solidification chamber (15); Graphite support (18) is disposed in the directional solidification cavity (15).

Images