Recycling and reusing system and method for solid content in polycrystalline silicon slag slurry

Abstract

The invention provides a system and a method for recycling solid content in polycrystalline silicon slag slurry, the system receives the polycrystalline silicon slag slurry generated by an upstream system, and chlorosilane, metal chloride and silicon powder are obtained after separation; comprising a slag slurry storage tank for receiving the polycrystalline silicon slag slurry generated by an upstream system, a filtering system for solid-liquid separation, a chlorosilane storage tank, a first drying machine, a rectification device, a second drying machine, a silicon powder storage tank, a separator, a fluidized bed, a metal chloride storage tank and a high-boiling cracking device, the method is realized by adopting the system, and the solid content in the polycrystalline silicon slag slurry is recycled.

Description

Technical Field

[0001] The invention relates to a system and method for recovering and reusing solid contents, in particular to a system and method for recovering and reusing solid contents in polysilicon slurry. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] Both the silane fluidized bed method and the improved Siemens method use a cold hydrogenation process to prepare SiHCl3. This process will produce a large amount of chlorosilane-containing waste liquid (SiCl4, Si2Cl6, silicon powder, metal chlorides, etc.), which needs to be sent to the slurry high-boiling device for treatment and recycling. At present, the device can only effectively recover SiCl4 and Si2Cl6 through distillation and catalytic cracking devices. Among them, silicon powder, metal chlorides and other substances can only be hydrolyzed and treated as waste residues, which cannot be effectively utilized, and increase the pressure on sewage treatment.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] Purpose of the invention: The technical problem to be solved by the present invention is to provide a system and method for recycling solids in polysilicon slurry in view of the deficiencies in the prior art.

[0006] In order to solve the above technical problems, the present invention discloses a system and method for recycling solids in polysilicon slurry, wherein the system receives the polysilicon slurry produced by an upstream system, and obtains chlorosilane, metal chloride and silicon powder after separation.

[0007] Furthermore, the system comprises:

[0008] A slurry storage tank for receiving the polysilicon slurry generated by an upstream system, wherein the slurry storage tank is connected to a filtering system;

[0009] The filtering system performs solid-liquid separation on the polysilicon slurry to obtain liquid chlorosilane and wet material; and sends the liquid chlorosilane and the wet material to the chlorosilane storage tank and the first dryer respectively;

[0010] The chlorosilane storage tank is used to store the liquid chlorosilane and transport it to the downstream distillation device for processing;

[0011] The first dryer performs the first step of drying to obtain vaporized chlorosilane and dry material, and the vaporized chlorosilane and the dry material are respectively sent to the distillation device and the second dryer;

[0012] The second dryer performs a second drying to obtain silicon powder and high-temperature gas, and sends the silicon powder and the high-temperature gas to a silicon powder storage tank and a separator respectively;

[0013] The silicon powder storage tank is used to store the silicon powder and send it to the fluidized bed for treatment to finally obtain chlorosilane, hydrogen and silicon powder;

[0014] The separator separates the metal chloride and gas phase high boiling products in the high temperature gas and sends them to the metal chloride storage tank and the high boiling cracking device respectively;

[0015] The high boiling cracking device processes high boiling materials to obtain trichlorosilane and silicon tetrachloride.

[0016] Furthermore, the filtration system is a drum filtration system.

[0017] Furthermore, the rotary drum filtration system comprises:

[0018] A hollow drum shell (105); a chlorosilane waste liquid inlet (101) is provided on the upper portion of the drum shell (105) for receiving upstream waste liquid;

[0019] A first motor (100) is provided at one end of the drum shell (105); a rotating shaft (102) is provided at the output end of the first motor (100); the rotating shaft (102) extends horizontally into the drum shell (105) to drive a rotating drum (109) fixedly connected thereto to rotate; a filter cloth (104) is provided on the outer surface of the rotating drum (109) for filtering silicon powder in the waste liquid;

[0020] A chlorosilane clear liquid outlet (106) is provided in the middle of the drum (109), extending outside the drum shell (105) and used for discharging the clear liquid after filtering in the drum (109);

[0021] A scraper (107) is provided on the outside of the rotating drum (109) for scraping off the silicon powder filtered and adsorbed on the surface of the filter cloth (104);

[0022] A silicon powder temporary storage tank (108) is provided at the bottom of the drum shell (105) for temporarily storing the scraped silicon powder;

[0023] The drum housing (105) is also provided with a viewing mirror (103) for observing the internal conditions of the drum filtration system.

[0024] Furthermore, the first dryer and the second dryer have the same structure.

[0025] Furthermore, the structures of the first dryer and the second dryer specifically include:

[0026] A hollow drying barrel body is placed horizontally, wherein a heat preservation sleeve (203) is arranged on the outside of the drying barrel body; a waste residue inlet (204) is arranged on the top of the drying barrel body for receiving waste residue from an upstream device; a heating device is arranged inside the drying barrel body; a second motor (201) is arranged at one end of the drying barrel body, a rotating shaft (206) is fixedly arranged at the output end of the second motor (201), and a silicon powder agitator (207) is fixedly arranged on the rotating shaft (206); the silicon powder agitator (207) is arranged inside the drying barrel body for stirring;

[0027] The top of the drying barrel is also provided with a chlorosilane gas phase outlet (202), and the gas phase material heated and evaporated inside the drying barrel is output from the chlorosilane gas phase outlet (202) to a downstream device;

[0028] A silicon powder temporary storage tank (208) is provided at the bottom of the drying barrel for storing the dried material.

[0029] Furthermore, the high boiling point cracking device comprises:

[0030] A reactor (310), wherein a third material inlet (301) is provided on the upper side of the reactor (310) for receiving a material outputted from an upstream system; a catalyst is provided in the reactor (310), and a hydrogen chloride inlet (309) is provided at the bottom of the reactor (310) for introducing hydrogen chloride gas into the reactor (310); a gas distributor (308) is fixedly provided inside the reactor (310), and the gas distributor (308) is connected to the hydrogen chloride inlet (309) for dispersing the received hydrogen chloride gas into the reactor (310);

[0031] A third motor (302) is fixedly arranged on the top of the reaction kettle (310), and an output end of the third motor (302) extends into the interior of the reaction kettle (310) and is connected to a stirrer (306) for stirring;

[0032] The top of the reactor (310) is provided with a third material outlet (303) for outputting the gaseous material obtained after the reaction;

[0033] A third insulation jacket (305) and a heating device are provided outside the reaction kettle (310).

[0034] Furthermore, the heating device is a steam heating device, comprising a steam outlet (205, 304), a steam inlet (209, 307) and a steam pipeline for heating.

[0035] Furthermore, the separator comprises:

[0036] A separator barrel (410), wherein a fourth material inlet (407) is provided at the bottom of the side wall of the separator barrel (410) for receiving gaseous substances input from an upstream system; a condensing device is provided on the side wall of the separator barrel (410) for condensing the gaseous substances on the inner wall of the separator barrel (410); and a gas phase outlet (402) is provided at the top of the separator barrel (410) for outputting uncondensed gaseous substances;

[0037] A fourth motor (401) is fixedly arranged on the top of the separator barrel (410); an output end of the fourth motor (401) extends into the interior of the separator barrel (410) and is connected to a scraper (404); the fourth motor (401) drives the scraper (404) to rotate, and scrapes off the material condensed on the inner wall of the separator barrel (410);

[0038] The bottom of the separator barrel (410) is fixedly provided with a metal chloride temporary storage tank (408) and a cut-off valve (409) for temporarily storing and outputting the scraped material;

[0039] The condensing device comprises a circulating water inlet (403), a circulating water outlet (406) and a circulating water pipeline for condensation;

[0040] The outer side wall of the separator barrel (410) is also provided with a fourth heat-insulating sleeve (405).

[0041] The present invention also provides a method for recycling solids in polysilicon slurry, which is implemented by the above-mentioned system and includes the following steps:

[0042] Step 1, the slurry storage tank receives the polysilicon slurry generated by the upstream system;

[0043] Step 2, the filtration system performs solid-liquid separation on the polysilicon slurry to obtain liquid chlorosilane and wet material; and the liquid chlorosilane and the wet material are respectively sent to a chlorosilane storage tank and a first dryer;

[0044] Step 3, the chlorosilane storage tank stores the liquid chlorosilane and transports it to a downstream distillation device for processing;

[0045] Step 4, performing the first drying step, processing the wet material through the first dryer to obtain vaporized chlorosilane and dry material, and sending the vaporized chlorosilane and the dry material to the distillation device and the second dryer respectively;

[0046] Step 5, performing a second drying, processing the dry material through the second dryer to obtain silicon powder and high-temperature gas, and sending the silicon powder and the high-temperature gas to a silicon powder storage tank and a separator respectively;

[0047] Step 6, the silicon powder storage tank stores the silicon powder and sends it to a fluidized bed for treatment, thereby finally obtaining chlorosilane, hydrogen and silicon powder;

[0048] Step 7, treating the high-temperature gas through the separator, separating the metal chloride and gas-phase high-boiling substances in the high-temperature gas, and sending them to the metal chloride storage tank and the high-boiling cracking device respectively;

[0049] Step 8, the high-boiling cracking device processes the gas phase high-boiling substances to obtain trichlorosilane and silicon tetrachloride.

[0050] Beneficial effects:

[0051] The system and method designed in the present invention can recycle silicon powder for re-reaction to generate chlorosilane for recycling; metal chlorides such as AlCl3 are recovered, which reduces the content of metal impurities in polysilanes such as Si2Cl6, and can effectively avoid the deactivation of catalysts in catalytic cracking devices due to the presence of AlCl3, and extend the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0053] Figure 1 It is a schematic diagram of the overall system architecture and method flow of the present invention.

[0054] Figure 2 is a cross-sectional view of a rotary drum filtration system in one embodiment.

[0055] Figure 3 The figure is a schematic diagram of the overall structure of a rotary drum filter system in an embodiment.

[0056] Figure 4 Schematic diagram of the overall structure of a dryer in one embodiment.

[0057] Figure 5 The figure is a schematic diagram of the overall structure of a high boiling cracking device in one embodiment.

[0058] Figure 6 Schematic diagram of the overall structure of a separator in an embodiment. DETAILED DESCRIPTION

[0059] The overall idea of ​​the present invention is to design a new slurry treatment system and method to recover silicon powder for re-reaction to generate chlorosilane for recycling; metal chlorides such as AlCl3 are recovered to reduce the content of metal impurities in polysilanes such as Si2Cl6, which can effectively avoid the deactivation of the catalyst in the catalytic cracking device.

[0060] The present invention proposes a slurry solid content recovery and reuse process, which effectively separates the liquid and solid of the slurry produced by cold hydrogenation, and reuses all the outputs, effectively reducing the waste of resources and environmental pollution.

[0061] The key technical points of the present invention are: 1. The filtering method of the rotary drum can achieve liquid-solid separation without introducing too many impurities; 2. The two-step drying device can effectively separate various substances; 3. The separator can effectively separate low-boiling point metal chlorides such as AlCl3 from high-boiling substances to avoid the presence of metal chlorides during catalytic cracking of high-boiling substances and cause catalyst deactivation; 4. A fluidized bed is introduced into the slurry treatment system to react with Si powder by passing high-temperature HCl to recover chlorosilane.

[0062] The present invention provides a system and method for recycling solids in polysilicon slurry, such as Figure 1 As shown, the specific implementation method is as follows:

[0063] 1. In the technical scheme, the slurry treatment system proposed in the present invention receives the chlorosilane waste liquid generated from the cold hydrogenation device (upstream system), which contains: (SiCl4, Si2Cl6, silicon powder, metal chlorides, etc., Note: the main components of the polysilicon by-product chlorosilane residual liquid include monosilanes mainly composed of SiCl4 and SiHCl3, high boiling point components represented by Si2Cl6, metal chlorides introduced when adding catalysts, solid impurities Si powder and SiO2, etc.).

[0064] 2. Receive the cold hydrogenated slurry from the upstream system, store it in the slurry storage tank, and then pump it to the drum filter system for filtration. The drum filter system uses vacuum equipment to draw negative pressure to separate the liquid phase and the solid phase through a porous ceramic drum (with a filter element on the outer layer, which can be made of various types of filter cloth such as carbon fiber). Si powder and metal chloride in solid form are separated by a scraper next to the drum and fall into the dryer 1 for the first step of drying. The chlorosilane liquid phase enters the chlorosilane storage tank and is sent to the distillation device for separation and purification.

[0065] like Figure 2 and Figure 3 As shown, the drum filtration system includes: 100 motor, 101 chlorosilane waste liquid inlet, 102 rotating shaft, 103 sight glass, 104 filter cloth, 105 vacuum pipeline, 106 chlorosilane clear liquid outlet, 107 scraper, 108 silicon powder temporary storage tank;

[0066] During operation, chlorosilane waste liquid enters the drum filter system from the chlorosilane waste liquid inlet 101, the motor 100 drives the shaft 102 to rotate, and the shaft 102 drives the drum 109 to rotate. The drum 109 is attached with a filter cloth 104, and the middle of the drum 109 is provided with a chlorosilane clear liquid outlet 106, which pumps the filtered clear liquid into the chlorosilane storage tank. Silicon powder adheres to the filter cloth 104, and the sight glass 103 can observe the internal situation. After reaching a certain thickness, it is dropped by the scraper 107 and sent to the silicon powder temporary storage tank 108.

[0067] 3. Carry out the first step of drying. The solid content falling into the dryer 1 is wet material (about 15% chlorosilane). The dryer is heated by steam tracing to raise the temperature to 110-130°C. The heating method of the dryer is stirring heating. The rotation of the shaft is controlled by the motor to drive the silicon powder agitator. After the chlorosilane is vaporized, it enters the tail gas condensation device from the chlorosilane gas phase outlet for recovery. The waste residue after the first step of drying enters the silicon powder tank for temporary storage and then is sent to the dryer 2.

[0068] Among them, Figure 4 As shown, dryer 1 and dryer 2 have the same structure, including: 201 motor, 202 chlorosilane gas phase outlet, 203 insulation cover, 204 waste residue inlet, 205 steam outlet, 206 rotating shaft, 207 silicon powder agitator, 208 silicon powder temporary storage tank, 209 steam inlet;

[0069] During operation, the dryer receives waste residue from the waste residue inlet 204 and falls into the dryer cavity. The dryer is provided with a steam heating device. The motor 201 rotates to drive the silicon powder agitator 207 to rotate, so that the material is fully dispersed and evenly heated. The evaporated gas phase material enters the tail gas condensation device from the chlorosilane gas phase outlet 202, and the dried waste residue enters the silicon powder temporary storage tank 208.

[0070] 4. The main components of the material after the first step of drying are Si powder, a small amount of SiCl4, Si2Cl6 and other high-boiling substances, and AlCl3 (boiling point 178°C). In the dryer 2, the second step of drying is carried out, that is, the material is heated to 180-220°C by electric heating, and a small amount of SiCl4, high-boiling substances and AlCl3 are evaporated and enter the separator.

[0071] 5. The separator consists of an agitator with a scraper and a condensed water cooling device (the gas phase material is cooled to 140-150℃). The gas phase high boiling materials are sent to the high boiling cracking device, and low boiling point metal chlorides such as AlCl3 are condensed on the separator cylinder and separated by the scraper and sent to the metal chloride storage tank for recovery. (It effectively avoids low boiling point metal chlorides from entering the high boiling cracking device and complexing with the catalyst to cause catalyst deactivation, and AlCl3 has certain economic value).

[0072] Among them, Figure 5As shown, the high boiling cracking device includes: 301 material inlet, 302 motor, 303 material outlet, 304 steam outlet, 305 insulation jacket, 306 stirrer, 307 steam inlet, 308 gas distributor, 309 HCl inlet;

[0073] During operation, the high-boiling cracking device receives high-boiling products from the separator and the bottom of the distillation device from the material inlet 301. The reactor 310 is filled with a liquid catalyst, and HCl gas is introduced from the HCl inlet 309. The distributor 308 disperses the gas in the reactor. The motor 302 drives the stirrer 306 to rotate, further fully mixing the materials and enhancing the reaction. The reactor 310 is equipped with a steam heating device to provide the heat required for the reaction. The gaseous phase material after the reaction enters the distillation device from the material outlet 303.

[0074] like Figure 6 As shown, the separator includes: a motor 401, a gas phase outlet 402, a circulating water inlet 403, a scraper 404, a heat preservation sleeve 405, a circulating water outlet 406, a material inlet 407, a metal chloride temporary storage tank 408, a cut-off valve 409, and a separator barrel 410;

[0075] During operation, the gas phase material of the dryer 2 enters the separator from the material inlet 407. The separator is provided with a circulating water condensation device (including a circulating water inlet 403 and a circulating water outlet 406), which condenses the metal chloride in the material and deposits it on the inner wall of the separator, and the uncondensed gas phase high boiling enters the next device from the gas phase outlet 402. The scraper 404 of the separator is driven by the motor 401, and the metal chloride deposited on the inner wall is dropped into the metal chloride temporary storage tank 408.

[0076] 6. The silicon powder in the second drying process falls into the silicon powder storage tank. At this time, the silicon powder enters the fluidized bed through pressurized transportation and reacts with high-temperature hydrogen chloride HCl (280-320℃) to generate chlorosilane and hydrogen (main reaction: Si+3HCl——SiHCl3+H2). After the silicon powder is filtered by the dust collector, it enters the condensation recovery device, and the condensed chlorosilane is sent to the distillation device for distillation and purification.

[0077] In another embodiment, the aforementioned drum filtration system can be replaced with a centrifugal filtration system, and then heated and evaporated to achieve the effect of liquid-solid separation, and the fluidized bed can be heated by electric heating to maintain the temperature in the bed.

[0078] In another embodiment, with a polysilicon production capacity of 100,000 tons / year, the monthly loss of silicon powder reaches 800 tons. Through the technical solution of the present application, the relatively pure Si powder can be effectively separated and recycled, which has great economic benefits and reduces wastewater discharge. The traditional treatment method does not pass through the second dryer, and the silicon powder, a small amount of SiCl4, and high boiling products directly enter the hydrolysis device, and finally form waste liquid and waste residue and are discharged.

[0079] In a specific implementation, the present application provides a computer storage medium and a corresponding data processing unit, wherein the computer storage medium can store a computer program, and when the computer program is executed by the data processing unit, the invention content of a system and method for recycling solids in polysilicon slurry provided by the present invention and some or all steps in each embodiment can be executed. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0080] Those skilled in the art can clearly understand that the technical solutions in the embodiments of the present invention can be implemented by means of computer programs and their corresponding general hardware platforms. Based on such an understanding, the technical solutions in the embodiments of the present invention can be essentially or partly contributed to the prior art in the form of computer programs, i.e., software products, which can be stored in a storage medium and include several instructions for enabling a device including a data processing unit (which can be a personal computer, a server, a single-chip microcomputer, an MCU or a network device, etc.) to execute the methods described in various embodiments of the present invention or certain parts of the embodiments.

[0081] The present invention provides a system and method for recycling solids in polysilicon slurry. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A system for recovering and reusing solids in polysilicon slurry, characterized in that: The system receives the polysilicon slurry produced by the upstream system, and obtains chlorosilane, metal chloride and silicon powder after separation.

2. The system for recycling solids in polysilicon slurry according to claim 1, characterized in that: The system comprises: A slurry storage tank for receiving the polysilicon slurry generated by an upstream system, wherein the slurry storage tank is connected to a filtering system; The filtering system performs solid-liquid separation on the polysilicon slurry to obtain liquid chlorosilane and wet material; and sends the liquid chlorosilane and the wet material to the chlorosilane storage tank and the first dryer respectively; The chlorosilane storage tank is used to store the liquid chlorosilane and transport it to the downstream distillation device for processing; The first dryer performs the first step of drying to obtain vaporized chlorosilane and dry material, and the vaporized chlorosilane and the dry material are respectively sent to the distillation device and the second dryer; The second dryer performs a second step of drying to obtain silicon powder and high-temperature gas, and sends the silicon powder and the high-temperature gas to a silicon powder storage tank and a separator respectively; The silicon powder storage tank is used to store the silicon powder and send it to the fluidized bed for treatment to finally obtain chlorosilane, hydrogen and silicon powder; The separator separates the metal chloride and gas phase high boiling products in the high temperature gas and sends them to the metal chloride storage tank and the high boiling cracking device respectively; The high-boiling cracking device processes the gas phase high-boiling substances to obtain trichlorosilane and silicon tetrachloride.

3. The system for recycling solids in polysilicon slurry according to claim 2, characterized in that: The filtration system is a drum filtration system.

4. The system for recycling solids in polysilicon slurry according to claim 3, characterized in that: The rotary drum filtration system comprises: A hollow drum shell (105); a chlorosilane waste liquid inlet (101) is provided on the upper portion of the drum shell (105) for receiving upstream waste liquid; A first motor (100) is provided at one end of the drum shell (105); a first rotating shaft (102) is provided at the output end of the first motor (100); the first rotating shaft (102) extends horizontally into the drum shell (105) to drive a rotating drum (109) fixedly connected thereto to rotate; a filter cloth (104) is provided on the outer surface of the rotating drum (109) for filtering silicon powder in the waste liquid; A chlorosilane clear liquid outlet (106) is provided in the middle of the drum (109), extending outside the drum shell (105) and used for discharging the clear liquid after filtering in the drum (109); A scraper (107) is provided on the outside of the rotating drum (109) for scraping off the silicon powder filtered and adsorbed on the surface of the filter cloth (104); A silicon powder temporary storage tank (108) is provided at the bottom of the drum shell (105) for temporarily storing the scraped silicon powder; The drum housing (105) is also provided with a viewing mirror (103) for observing the internal conditions of the drum filtration system.

5. The system for recycling solids in polysilicon slurry according to claim 2, characterized in that: The first dryer and the second dryer have the same structure.

6. The system for recycling solids in polysilicon slurry according to claim 2, characterized in that: The structures of the first dryer and the second dryer specifically include: A hollow drying barrel body is placed horizontally, wherein a heat preservation sleeve (203) is arranged on the outside of the drying barrel body; a waste residue inlet (204) is arranged on the top of the drying barrel body for receiving waste residue from an upstream device; a heating device is arranged inside the drying barrel body; a second motor (201) is arranged at one end of the drying barrel body, a second rotating shaft (206) is fixedly arranged at the output end of the second motor (201), and a silicon powder agitator (207) is fixedly arranged on the second rotating shaft (206); the silicon powder agitator (207) is arranged inside the drying barrel body for stirring; The top of the drying barrel is also provided with a chlorosilane gas phase outlet (202), and the gas phase material heated and evaporated inside the drying barrel is output from the chlorosilane gas phase outlet (202) to a downstream device; A silicon powder temporary storage tank (208) is provided at the bottom of the drying barrel for storing the dried material.

7. The system for recycling solids in polysilicon slurry according to claim 2, characterized in that: The high boiling cracking device comprises: A reactor (310), wherein a third material inlet (301) is provided on the upper side of the reactor (310) for receiving a material outputted from an upstream system; a catalyst is provided in the reactor (310), and a hydrogen chloride inlet (309) is provided at the bottom of the reactor (310) for introducing hydrogen chloride gas into the reactor (310); a gas distributor (308) is fixedly provided inside the reactor (310), and the gas distributor (308) is connected to the hydrogen chloride inlet (309) for dispersing the received hydrogen chloride gas into the reactor (310); A third motor (302) is fixedly arranged on the top of the reaction kettle (310), and an output end of the third motor (302) extends into the interior of the reaction kettle (310) and is connected to a stirrer (306) for stirring; The top of the reactor (310) is provided with a third material outlet (303) for outputting the gaseous material obtained after the reaction; A third insulation jacket (305) and a heating device are provided outside the reaction kettle (310).

8. A system for recycling solids in polysilicon slurry according to claim 6 or 7, characterized in that: The heating device is a steam heating device, comprising a steam outlet (205, 304), a steam inlet (209, 307) and a steam pipeline for heating.

9. The system for recycling solids in polysilicon slurry according to claim 2, characterized in that: The separator comprises: A separator barrel (410), wherein a fourth material inlet (407) is provided at the bottom of the side wall of the separator barrel (410) for receiving gaseous substances input from an upstream system; a condensing device is provided on the side wall of the separator barrel (410) for condensing the gaseous substances on the inner wall of the separator barrel (410); and a gas phase outlet (402) is provided at the top of the separator barrel (410) for outputting uncondensed gaseous substances; A fourth motor (401) is fixedly arranged on the top of the separator barrel (410); an output end of the fourth motor (401) extends into the interior of the separator barrel (410) and is connected to a scraper (404); the fourth motor (401) drives the scraper (404) to rotate, and scrapes off the material condensed on the inner wall of the separator barrel (410); The bottom of the separator barrel (410) is fixedly provided with a metal chloride temporary storage tank (408) and a cut-off valve (409) for temporarily storing and outputting the scraped material; The condensing device comprises a circulating water inlet (403), a circulating water outlet (406) and a circulating water pipeline for condensation; The outer side wall of the separator barrel (410) is also provided with a fourth heat-insulating sleeve (405).

10. A method for recycling solids in polysilicon slurry, characterized in that: The method is implemented by using the system described in any one of claims 2 to 9, comprising the following steps: Step 1, the slurry storage tank receives the polysilicon slurry generated by the upstream system; Step 2, the filtration system performs solid-liquid separation on the polysilicon slurry to obtain liquid chlorosilane and wet material; and the liquid chlorosilane and the wet material are respectively sent to a chlorosilane storage tank and a first dryer; Step 3, the chlorosilane storage tank stores the liquid phase chlorosilane and transports it to a downstream distillation device for processing; Step 4, performing the first drying step, processing the wet material through the first dryer to obtain vaporized chlorosilane and dry material, and sending the vaporized chlorosilane and the dry material to the distillation device and the second dryer respectively; Step 5, performing a second drying, processing the dry material through the second dryer to obtain silicon powder and high-temperature gas, and sending the silicon powder and the high-temperature gas to a silicon powder storage tank and a separator respectively; Step 6, the silicon powder storage tank stores the silicon powder and sends it to a fluidized bed for treatment, thereby finally obtaining chlorosilane, hydrogen and silicon powder; Step 7, treating the high-temperature gas through the separator, separating the metal chloride and gas-phase high-boiling substances in the high-temperature gas, and sending them to the metal chloride storage tank and the high-boiling cracking device respectively; Step 8, the high-boiling cracking device processes the gas phase high-boiling substances to obtain trichlorosilane and silicon tetrachloride.

Images