A polysilicon post-treatment process and apparatus

Abstract

The application discloses a kind of polysilicon post-processing process and device, the process includes sequentially linked closed transport, low-temperature plasma fragmentation, composite cleaning, microwave vacuum drying, grading screening and six big procedures of finished product packaging, each procedure is closed and is linked, inert gas protection is protected throughout;The device includes sequentially arranged reduction furnace, closed transport channel, low-temperature plasma fragmentation device, composite cleaning device, microwave vacuum drying cavity, grading screening device and finished product packaging device along the material conveying direction, and the composite cleaning device includes sequentially connected multiple-unit cleaning structure.The application realizes efficient, low-consumption, clean post-processing of polysilicon by the collaborative design of process and device, avoids impurity introduction and secondary pollution, accurately controls the purity and surface quality of polysilicon, and adapts to the demand of photovoltaic and semiconductor industry.

Description

Technical Field

[0001] This invention relates to the field of polysilicon post-processing technology, and in particular to a polysilicon post-processing process and apparatus. Background Technology

[0002] Polysilicon is a core raw material for the photovoltaic and semiconductor industries, and its purity and surface quality directly determine the performance of downstream products. Currently, the industrial production of polysilicon mostly adopts the modified Siemens process. After being deposited in a reduction furnace, the product needs to undergo a series of post-processing steps, such as crushing, cleaning, drying, grading, and testing, to remove contaminants such as chlorosilanes, metallic impurities, and dust adhering to the surface, while shaping large pieces of polysilicon into particles that meet specifications.

[0003] Existing polysilicon post-processing technologies have many shortcomings: 1. The crushing process mostly uses mechanical impact crushing, which easily generates a lot of dust. In addition, the wear and tear of the equipment during the crushing process will introduce metal impurities such as iron and nickel, resulting in a decrease in the purity of polysilicon.

[0004] 2. The cleaning process often uses alternating acid and alkali cleaning combined with deionized water rinsing, which is time-consuming and consumes a lot of water. In addition, the residual acid and alkali solutions can easily cause secondary pollution on the polycrystalline silicon surface, affecting the product qualification rate.

[0005] 3. The drying process often uses hot air drying or vacuum drying. Hot air drying easily introduces impurities from the air, while vacuum drying is inefficient, energy-intensive, and the polycrystalline silicon surface easily absorbs moisture after drying. 4. The material transfer process between different processes is poorly sealed, which can easily cause secondary contamination of materials. Furthermore, the process connections are not smooth, resulting in low production efficiency.

[0006] To address these issues, the industry has proposed several improvement solutions, such as using airflow crushing instead of mechanical crushing to reduce impurity introduction and employing ultrasonic cleaning to assist acid-base cleaning and improve cleaning efficiency. However, these solutions have not fundamentally solved the core pain points in polysilicon post-processing, including difficulty in purity control, high energy consumption, low efficiency, and secondary pollution. Therefore, developing a high-efficiency, low-consumption, environmentally friendly post-processing technology and equipment that can precisely control the purity and surface quality of polysilicon has become an urgent need in the current polysilicon production field. Summary of the Invention

[0007] The technical problems to be solved by this invention are: mechanical crushing easily introduces metal impurities in existing polysilicon post-processing processes; traditional cleaning methods consume a lot of water and are prone to secondary pollution; hot air or vacuum drying introduces impurities or has low efficiency and high energy consumption; and the core pain points are: poor sealing of each process leads to secondary pollution and poor process connection results in low production efficiency.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a polycrystalline silicon post-processing process, comprising the following steps: Step 1, closed transport: The polycrystalline silicon block is transported through a closed transport channel filled with inert gas, avoiding contact with the outside world throughout the process; Step 2, crushing process, using low-temperature plasma crushing method, the polycrystalline silicon block is crushed by a low-temperature plasma crushing device; Step 3, composite cleaning, adopts a multi-step combined cleaning mode, and uses a composite cleaning device to deeply clean the broken polycrystalline silicon particles. Step four, drying treatment, using microwave vacuum drying method, the cleaned polycrystalline silicon particles are dried through a microwave vacuum drying chamber; Step 5, grading and screening: The dried polycrystalline silicon particles are graded using a grading and screening device to classify particles of different sizes and recycle unqualified particles. Step 6: Finished product packaging. Inert gas protection or vacuum packaging is used to package qualified polycrystalline silicon particles using a finished product packaging device. Each step is connected in a closed system, and the entire process is protected by inert gas and controlled by precise processes.

[0009] Preferably, in step one, the polycrystalline silicon block produced by the reduction furnace is sent into the post-processing system through a closed transfer channel. The transfer channel is filled with inert gas, which is high-purity argon, and the pressure inside the channel is maintained at 0.12-0.15 MPa. During the transfer process, the material position is monitored in real time by an infrared detection module to ensure stable transfer.

[0010] Preferably, the specific process of step two is as follows: the polycrystalline silicon block is sent into the sealed crushing chamber of the low-temperature plasma crushing device, the crushing chamber is pre-filled with high-purity argon gas and the vacuum degree is maintained at 10-15 Pa, and the temperature is controlled at -50~-30℃; a high-energy plasma beam is generated by the plasma generator and acts on the preset fracture surface of the polycrystalline silicon block, so that the polycrystalline silicon block is crushed along the preset path, and the particle size after crushing is controlled at 5-50 mm.

[0011] Preferably, in step three, the combined cleaning includes the following steps: S31, Plasma cleaning unit cleaning; S32, Acid cleaning unit cleaning; S33, Ultrapure water ultrasonic cleaning unit cleaning; S34, Ion exchange cleaning unit cleaning; After cleaning, the impurity content on the polycrystalline silicon surface is tested to ensure that the total content of metal impurities is ≤1ppm; The process includes: a plasma cleaning unit to remove organic pollutants and adsorbed impurities; an acid cleaning unit to remove metal oxides and silicon oxides; an ultrapure water ultrasonic cleaning unit to rinse away residual chemicals and dissolved impurities; and an ion exchange cleaning unit to remove residual metal ions and anionic impurities.

[0012] Preferably, step S31 uses an oxygen-argon mixed plasma with a volume ratio of 1:3 to 1:5, a plasma power of 300-500W, and a cleaning time of 5-10 minutes. Step S32 uses a dilute hydrofluoric acid solution with a mass fraction of 0.5-1.5%, controls the temperature at 20-30℃, and soaks for 10-15 minutes, while using a low-frequency ultrasonic generator of 20-40kHz for assistance. Step S34 employs an ion exchange cell, which is filled with a mixture of styrene-based strong acid cation exchange resin and strong base anion exchange resin, with the flow rate controlled at 0.5-1 m / h.

[0013] Preferably, step four specifically involves: sending the cleaned polycrystalline silicon particles into a microwave vacuum drying chamber, maintaining a vacuum level of 5-10 Pa in the microwave vacuum drying chamber, using a microwave generator for microwave heating, with a microwave frequency of 2450 MHz, a power adjustment of 200-400 W, a heating temperature controlled at 80-120 ℃, and a drying time of 20-30 min. During the drying process, a high-purity argon gas purging device is used to remove water vapor and trace impurities generated during drying. After drying, the moisture content of the polycrystalline silicon particles is ≤0.01%.

[0014] Preferably, in step five, the grading and screening device uses a multi-layer vibrating screen to grade the dried polycrystalline silicon particles. The screen mesh sizes of the vibrating screen are 50mm, 20mm, and 5mm, respectively, dividing the particles into three grades: large particles, medium particles, and small particles. Among them, large particles are returned to the low-temperature plasma crushing device for re-crushing through the reflux channel, small particles are used as by-products for secondary processing of photovoltaic-grade polycrystalline silicon material, and medium particles are qualified products that enter the next step of packaging. The grading process is protected by an inert gas protection device.

[0015] Preferably, the finished product packaging process is completed by a finished product packaging device. First, the qualified polycrystalline silicon particles are subjected to infrared detection and purity detection by the detection unit. After passing the detection, they are sent into the closed packaging cavity of the finished product packaging device and packaged using a vacuum packaging machine.

[0016] A polysilicon post-processing device includes a reduction furnace, a closed transfer channel, a low-temperature plasma crushing device, a composite cleaning device, a microwave vacuum drying chamber, a grading and screening device, and a finished product packaging device arranged sequentially along the material conveying direction. The composite cleaning device includes a plasma cleaning unit, an acid cleaning unit, an ultrapure water ultrasonic cleaning unit, and an ion exchange cleaning unit connected in sequence. The input end of the closed transfer channel is located on one side of the reduction furnace, and the output end is located inside the low-temperature plasma crushing device. A feeding channel is arranged at an angle on one side of the low-temperature plasma crushing device, and a composite cleaning device is connected through the feeding channel. The microwave vacuum drying chamber is located on one side of the feeding end of the composite cleaning device. The grading and screening device includes a multi-layer vibrating screen and an inert gas protection device covered on the multi-layer vibrating screen.

[0017] Preferably, the plasma cleaning unit is a vertically arranged cylindrical shape, with a screen horizontally sliding in the middle of the plasma cleaning unit and a gas supply pipeline connected to the bottom end. Both the acid cleaning unit and the ultrapure water ultrasonic cleaning unit are equipped with low-frequency ultrasonic generators. Both the acid cleaning unit and the ultrapure water ultrasonic cleaning unit include a pool body and a flexible chain conveyor belt that is rotatably arranged in the pool body. The ion exchange cleaning unit includes a tank and a support basket suspended inside the tank. Filter plates are provided on the side walls and bottom of the support basket, and the pore size of the filter plates is smaller than the particle size of the crushed material.

[0018] This invention provides a polycrystalline silicon post-processing process and apparatus, which has the following beneficial effects.

[0019] 1. Through the specific structural design of the low-temperature plasma crushing device, the device utilizes a sealed crushing chamber, a plasma generator, and a high-purity argon pre-filling structure to adopt a low-temperature plasma crushing method without mechanical contact. The plasma generator produces a high-energy plasma beam that acts on the pre-set fracture surface of polycrystalline silicon. The sealed crushing chamber maintains a vacuum of 10-15 Pa and a low-temperature environment of -50 to -30°C. With the protection of high-purity argon, the structure avoids the introduction of metal impurities due to equipment wear during the crushing process, while reducing dust generation and ensuring the purity of polycrystalline silicon.

[0020] 2. Through the modular structure design of the composite cleaning device, the device includes a plasma cleaning unit, an acid cleaning unit, an ultrapure water ultrasonic cleaning unit, and an ion exchange cleaning unit connected in sequence. Each unit works in concert: the plasma cleaning unit introduces oxygen-argon mixed plasma, the acid cleaning unit uses dilute hydrofluoric acid solution with ultrasonic assistance, the ultrapure water ultrasonic cleaning unit uses high-purity deionized water for ultrasonic rinsing, and the ion exchange cleaning unit is filled with a specific mixed resin. Through this multi-unit structure of progressive cleaning, water consumption and cleaning time are reduced, acid and alkali residues are avoided, and the total impurity content on the polycrystalline silicon surface is ensured to be ≤1ppm.

[0021] 3. Through the structural design of the microwave vacuum drying chamber, the chamber can maintain a vacuum of 5-10 Pa. With the built-in microwave generator, microwave heating is achieved. At the same time, a high-purity argon purging device is used. The vacuum environment isolates air impurities, the microwave generator achieves uniform and efficient heating, and the purging device removes water vapor and trace impurities in time. The structure avoids the introduction of air impurities and moisture adsorption, reduces energy consumption, and ensures that the moisture content of polycrystalline silicon particles after drying is ≤0.01%. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0023] In the diagram: 1. Enclosed transfer channel; 2. Low-temperature plasma crushing device; 3. Composite cleaning device; 4. Microwave vacuum drying chamber; 5. Grading and screening device; 6. Finished product packaging device; 7. Reduction furnace; 8. Infrared detection module; 31. Plasma cleaning unit; 32. Acid cleaning unit; 321. Low-frequency ultrasonic generator; 33. Ultrapure water ultrasonic cleaning unit; 34. Ion exchange cleaning unit; 51. Multi-layer vibrating screen; 52. Reflux channel; 53. Inert gas protection device. Detailed Implementation

[0024] This invention provides a polycrystalline silicon post-processing technology for processing polycrystalline silicon blocks produced by reduction furnace 7, removing surface contaminants and shaping them into granules that meet specifications. The entire process employs a closed-loop connection and inert gas protection to ensure the purity and surface quality of the polycrystalline silicon. The specific processing flow is as follows: Step 1, Closed Transfer: The polycrystalline silicon blocks produced by the reduction furnace 7 are transferred through a closed transfer channel 1 filled with inert gas, avoiding contact with the outside environment throughout the process; the inert gas used in the transfer channel 1 is high-purity argon, and the pressure inside the channel is maintained at 0.12-0.15MPa; during the transfer process, the material position is monitored in real time by an infrared detection module 8 to ensure smooth transfer, avoid material collisions that generate dust, and smoothly send the polycrystalline silicon blocks into the subsequent processes of the post-processing system.

[0025] Step 2, Crushing Process: The polycrystalline silicon block is crushed using a low-temperature plasma crushing device 2. The specific process is as follows: the polycrystalline silicon block after being transported in a closed manner is sent into the sealed crushing chamber of the low-temperature plasma crushing device 2. The crushing chamber is pre-filled with high-purity argon gas and the vacuum degree is maintained at 10-15 Pa, and the temperature is controlled at -50~-30℃. A high-energy plasma beam is generated by a plasma generator and acts on the preset fracture surface of the polycrystalline silicon block, causing the polycrystalline silicon block to be crushed along a preset path. The particle size after crushing is controlled at 5-50 mm. After crushing, the polycrystalline silicon particles are sent to the next process.

[0026] Step 3, Composite Cleaning: A multi-step combined cleaning mode is adopted. The crushed polycrystalline silicon particles are deeply cleaned using composite cleaning device 3. After cleaning, the impurity content on the polycrystalline silicon surface is measured to ensure that the total metal impurity content is ≤1ppm. Specifically, it includes the following sub-steps: S31, Plasma Cleaning Unit 31 Cleaning: Oxygen-argon mixed plasma is used, with a volume ratio of 1:3-1:5, plasma power of 300-500W, and cleaning time of 5-10min. The plasma cleaning unit 31 removes organic contaminants and adsorbed impurities from the surface of polycrystalline silicon particles. S32, Acid Cleaning Unit 32 Cleaning: Use a dilute hydrofluoric acid solution with a mass fraction of 0.5-1.5%, control the temperature at 20-30℃, and soak for 10-15 minutes. At the same time, use a low-frequency ultrasonic generator 321 with a frequency of 20-40kHz to assist in the cleaning. The acid cleaning unit 32 removes metal oxides and silicon oxide impurities from the surface of polycrystalline silicon particles. S33, Ultrapure Water Ultrasonic Cleaning Unit 33 Cleaning: High-purity deionized water with a resistivity ≥18.2MΩ·cm is used to ultrasonically rinse the polycrystalline silicon particles through the ultrapure water ultrasonic cleaning unit 33 to remove residual hydrofluoric acid and dissolved impurities on the particle surface. S34, Ion Exchange Cleaning Unit 34 Cleaning: An ion exchange cell is used, which is filled with a mixture of styrene-based strong acid cation exchange resin and strong base anion exchange resin. The flow rate is controlled at 0.5-1 m / h. The ion exchange cleaning unit 34 removes residual metal ions and anion impurities on the surface of polycrystalline silicon particles. After the composite cleaning is completed, the polycrystalline silicon particles are sent to the next drying process.

[0027] Step 4, Drying: Microwave vacuum drying is used to dry the cleaned polycrystalline silicon particles in microwave vacuum drying chamber 4. Specifically, the polycrystalline silicon particles after composite cleaning are sent into microwave vacuum drying chamber 4, which maintains a vacuum of 5-10 Pa. A microwave generator is used for microwave heating at a frequency of 2450 MHz and a power of 200-400 W. The heating temperature is controlled at 80-120℃, and the drying time is 20-30 minutes. During the drying process, a high-purity argon gas purging device is used to remove water vapor and trace impurities generated during drying. After drying, the moisture content of the polycrystalline silicon particles is ≤0.01%. After drying, the polycrystalline silicon particles are sent to the grading and screening process.

[0028] Step 5, Grading and Screening: The dried polycrystalline silicon particles are graded using a grading and screening device 5 to classify particles of different sizes and recycle unqualified particles. Specifically, the grading and screening device 5 uses a multi-layer vibrating screen 51 to grade the dried polycrystalline silicon particles. The screen mesh sizes of the vibrating screen 51 are 50mm, 20mm, and 5mm, dividing the particles into three grades: large particles, medium particles, and small particles. Among them, large particles are returned to the low-temperature plasma crushing device 2 for re-crushing through the return channel 52, small particles are used as by-products for secondary processing of photovoltaic-grade polycrystalline silicon material, and medium particles are qualified products that enter the next finished product packaging process. During the grading process, an inert gas protection device 53 is used to protect against dust pollution and particle oxidation.

[0029] Step Six, Finished Product Packaging: Qualified polycrystalline silicon particles are packaged using inert gas protection or vacuum packaging via the finished product packaging device 6. Specifically, the qualified polycrystalline silicon particles are first subjected to infrared and purity testing by the detection unit. After passing the tests, they are sent to the sealed packaging cavity of the finished product packaging device 6 and packaged using a vacuum packaging machine. The packaging material is food-grade polyethylene film that has undergone high-purity cleaning treatment, and the weight of each package is controlled at 25kg or 50kg. After packaging, product labels are affixed using a labeling device, indicating batch, purity, particle size grade, and other information. The finished products are then sent to the finished product warehouse for storage, completing the entire polycrystalline silicon post-processing process.

[0030] Each step is handled in a closed system, with inert gas protection and precise process control throughout to prevent direct contact between polysilicon and the external environment, eliminate secondary pollution, and ensure the purity and surface quality of polysilicon products to meet the needs of the photovoltaic and semiconductor industries.

[0031] A polycrystalline silicon post-processing device includes a reduction furnace 7, a closed transfer channel 1, a low-temperature plasma crushing device 2, a composite cleaning device 3, a microwave vacuum drying chamber 4, a grading and screening device 5, and a finished product packaging device 6 arranged sequentially along the material conveying direction. The composite cleaning device 3 includes a plasma cleaning unit 31, an acid cleaning unit 32, an ultrapure water ultrasonic cleaning unit 33, and an ion exchange cleaning unit 34 connected in sequence. The input end of the closed transfer channel 1 is located on one side of the reduction furnace 7, and the output end is located inside the low-temperature plasma crushing device 2. A feeding channel is arranged at an incline on one side of the low-temperature plasma crushing device 2, and the composite cleaning device 3 is connected through the feeding channel. The microwave vacuum drying chamber 4 is located on one side of the feeding end of the composite cleaning device 3. The grading and screening device 5 includes a multi-layer vibrating screen 51 and an inert gas protection device 52 covered on the multi-layer vibrating screen 51.

[0032] The enclosed transfer channel 1 is equipped with a conveying device, which includes a mobile cart. The mobile cart is used to place polycrystalline silicon material and transport the material to the interior of the low-temperature plasma crushing device 2. The low-temperature plasma crushing device 2 is equipped with a plasma generator. The polycrystalline silicon block is crushed by the plasma generator. After crushing, the material is directly discharged through the feeding channel and enters the plasma cleaning unit 31 of the composite cleaning device 3.

[0033] The plasma cleaning unit 31 is a vertically arranged cylindrical shape. A screen is horizontally slidably arranged in the middle of the plasma cleaning unit 31, and a gas supply pipeline is connected to the bottom end. Both the acid cleaning unit 32 and the ultrapure water ultrasonic cleaning unit 33 are equipped with low-frequency ultrasonic generators 321. Both the acid cleaning unit 32 and the ultrapure water ultrasonic cleaning unit 33 include a pool body and a flexible chain conveyor belt rotatably arranged in the pool body. The ion exchange cleaning unit 34 includes a pool body and a support basket suspended inside the pool body. Filter plates are provided on the side walls and bottom of the support basket, and the pore size of the filter plates is smaller than the particle size of the crushed material.

[0034] A hydraulic cylinder is provided in the middle of the plasma cleaning unit 31. The output end of the hydraulic cylinder is located inside the plasma cleaning unit 31. The output end of the hydraulic cylinder is connected to a screen that is horizontally slidably arranged inside the plasma cleaning unit 31. The screen is driven to receive the material. After receiving the material, the polycrystalline silicon particles are cleaned by oxygen-argon mixed plasma. After cleaning, the screen is pulled to make the material fall and enter the acid cleaning unit 32 for cleaning.

[0035] When the material falls into the acid cleaning unit 32, it falls directly onto the flexible chain conveyor belt. The material is transported by the flexible chain conveyor belt and is acid-washed by the acid inside the tank during the transportation process. After acid washing, the flexible chain conveyor belt transports the material to the outside of the tank and discharges it into the tank of the ultrapure water ultrasonic cleaning unit 33. The material is also supported by the flexible chain conveyor belt inside the ultrapure water ultrasonic cleaning unit 33 for cleaning. After cleaning, the material is sent out again.

[0036] The support basket inside the ion exchange cleaning unit 34 supports the material, allowing it to be immersed in a mixed system of styrene-based strong acid cation exchange resin and strong base anion exchange resin to remove residual metal ions and anion impurities. After cleaning, the impurity content on the polycrystalline silicon surface is tested to ensure that the total metal impurity content is ≤1ppm.

Claims

1. A polycrystalline silicon post-processing process, characterized in that, Includes the following steps: Step 1, closed transport: The polycrystalline silicon block is transported through a closed transport channel (1) filled with inert gas, avoiding contact with the outside world throughout the process; Step 2, crushing treatment, using low temperature plasma crushing method, the polycrystalline silicon block is crushed by low temperature plasma crushing device (2); Step 3, composite cleaning, adopting a multi-step combined cleaning mode, using a composite cleaning device (3) to deeply clean the broken polycrystalline silicon particles; Step 4, drying treatment, using microwave vacuum drying method, the cleaned polycrystalline silicon particles are dried through microwave vacuum drying chamber (4); Step 5, grading and screening: the dried polycrystalline silicon particles are graded by the grading and screening device (5) to classify particles of different sizes and recycle unqualified particles. Step 6, finished product packaging, using inert gas protection or vacuum packaging, the qualified polycrystalline silicon particles are packaged by the finished product packaging device (6); Each step is connected in a closed system, and the entire process is protected by inert gas and controlled by precise processes.

2. The polycrystalline silicon post-processing process according to claim 1, characterized in that: In step one, the polycrystalline silicon block produced by the reduction furnace (7) is sent to the post-processing system through a closed transfer channel (1). The transfer channel (1) is filled with inert gas, which is high-purity argon, and the pressure inside the channel is maintained at 0.12-0.15 MPa. During the transfer process, the material position is monitored in real time by an infrared detection module (8) to ensure smooth transfer.

3. The polycrystalline silicon post-processing process according to claim 1, characterized in that: The specific process of step two is as follows: the polycrystalline silicon block is sent into the closed crushing chamber of the low-temperature plasma crushing device (2). The crushing chamber is pre-filled with high-purity argon gas and the vacuum degree is maintained at 10-15Pa. The temperature is controlled at -50~-30℃. A high-energy plasma beam is generated by the plasma generator and acts on the preset fracture surface of the polycrystalline silicon block, so that the polycrystalline silicon block is crushed along the preset path. The particle size after crushing is controlled at 5-50mm.

4. The polycrystalline silicon post-processing process according to claim 1, characterized in that, Step three, the combined cleaning process, includes the following steps: S31, plasma cleaning unit (31) cleaning; S32, Acid cleaning unit (32) cleaning; S33, Ultrapure water ultrasonic cleaning unit (33) cleaning; S34, Ion exchange cleaning unit (34) cleaning; After cleaning, the impurity content on the polycrystalline silicon surface is tested to ensure that the total content of metal impurities is ≤1ppm; Among them: plasma cleaning unit (31) removes organic pollutants and adsorbed impurities, acid cleaning unit (32) removes metal oxide and silicon oxide impurities, ultrapure water ultrasonic cleaning unit (33) rinses residual agents and dissolves impurities, and ion exchange cleaning unit (34) removes residual metal ions and anionic impurities.

5. The polycrystalline silicon post-processing process according to claim 4, characterized in that: Step S31 uses an oxygen-argon mixed plasma with a volume ratio of 1:3 to 1:5, a plasma power of 300-500W, and a cleaning time of 5-10 minutes. Step S32 uses a dilute hydrofluoric acid solution with a mass fraction of 0.5-1.5%, controls the temperature at 20-30℃, and soaks for 10-15 minutes, while using a low-frequency ultrasonic generator (321) of 20-40kHz for assistance. Step S34 employs an ion exchange cell, which is filled with a mixture of styrene-based strong acid cation exchange resin and strong base anion exchange resin, with the flow rate controlled at 0.5-1 m / h.

6. The polycrystalline silicon post-processing process according to claim 1, characterized in that, The fourth step is as follows: the cleaned polycrystalline silicon particles are sent into the microwave vacuum drying chamber (4). The microwave vacuum drying chamber (4) maintains a vacuum of 5-10 Pa. A microwave generator is used for microwave heating. The microwave frequency is 2450 MHz, the power is adjusted to 200-400 W, the heating temperature is controlled at 80-120 ℃, and the drying time is 20-30 min. During the drying process, a high-purity argon gas purging device is used to remove water vapor and trace impurities generated during drying. After drying, the moisture content of the polycrystalline silicon particles is ≤0.01%.

7. The polycrystalline silicon post-processing process according to claim 1, characterized in that, In step five, the grading and screening device (5) uses a multi-layer vibrating screen (51) to grade the dried polycrystalline silicon particles. The screen mesh diameters of the vibrating screen (51) are 50mm, 20mm and 5mm, respectively, and the particles are divided into three grades: large particles, medium particles and small particles. Among them, the large particles are returned to the low-temperature plasma crushing device (2) through the return channel (52) for re-crushing, the small particles are used as by-products for secondary processing of photovoltaic-grade polycrystalline silicon material, and the medium particles are qualified products for the next step of packaging. The grading process is protected by an inert gas protection device (53).

8. The polycrystalline silicon post-processing process according to claim 1, characterized in that, The finished product packaging process is completed by the finished product packaging device (6). First, the qualified polycrystalline silicon particles are subjected to infrared detection and purity detection by the detection unit. After passing the detection, they are sent into the closed packaging cavity of the finished product packaging device (6) and packaged by a vacuum packaging machine.

9. A polycrystalline silicon post-processing apparatus, characterized in that: The device includes a reduction furnace (7), a closed transfer channel (1), a low-temperature plasma crushing device (2), a composite cleaning device (3), a microwave vacuum drying chamber (4), a grading and screening device (5), and a finished product packaging device (6) arranged sequentially along the material conveying direction. The composite cleaning device (3) includes a plasma cleaning unit (31), an acid cleaning unit (32), an ultrapure water ultrasonic cleaning unit (33), and an ion exchange cleaning unit (34) connected in sequence. The input end of the closed transfer channel (1) is located on one side of the reduction furnace (7), and the output end is located inside the low-temperature plasma crushing device (2). A feeding channel is arranged on one side of the low-temperature plasma crushing device (2), and the composite cleaning device (3) is connected through the feeding channel. The microwave vacuum drying chamber (4) is located on one side of the feeding end of the composite cleaning device (3). The grading and screening device (5) includes a multi-layer vibrating screen (51) and an inert gas protection device (52) covered on the multi-layer vibrating screen (51).

10. The polycrystalline silicon post-processing apparatus as described in claim 9, characterized in that: The plasma cleaning unit (31) is a vertically arranged cylindrical shape. A screen is horizontally slidably arranged in the middle of the plasma cleaning unit (31), and a gas supply pipeline is connected to the bottom end. Both the acid cleaning unit (32) and the ultrapure water ultrasonic cleaning unit (33) are equipped with low-frequency ultrasonic generators (321). Both the acid cleaning unit (32) and the ultrapure water ultrasonic cleaning unit (33) include a pool body and a flexible chain conveyor belt that is rotatably arranged in the pool body. The ion exchange cleaning unit (34) includes a pool body and a support basket suspended inside the pool body. Filter plates are provided on the side walls and bottom of the support basket. The pore size of the filter plates is smaller than the particle size of the crushed material.

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