A method and production system for recycling and reusing chlorosilane slurry

Abstract

This invention discloses a method for recycling and reusing chlorosilane slurry, comprising the following steps: Step 1: solid-liquid separation of the chlorosilane slurry to obtain crude chlorosilane liquid; Step 2: purification of the crude chlorosilane followed by reaction with ethanol to generate crude silicate ester; Step 3: purification of the crude silicate ester to obtain silicate ester product. This invention also discloses a system for recycling and reusing chlorosilane slurry, used to implement the above-mentioned method for recycling and reusing chlorosilane slurry. The method for recycling and reusing chlorosilane slurry of this invention facilitates the recovery of chlorosilanes in the chlorosilane slurry and their conversion into usable resources to obtain silicate ester product.

Description

TECHNICAL FIELD

[0001] The present application relates to a method and system for recycling chlorosilane slurry. BACKGROUND

[0002] At present, the improved Siemens method is mainly used in the production process of polycrystalline silicon. In the production process of polycrystalline silicon, the preparation of trichlorosilane by cold hydrogenation reaction is the main process. Among them, the silicon powder is reacted at a specific temperature in the fluidized bed to prepare chlorosilane, which contains trichlorosilane, silicon tetrachloride, dichlorosilane, etc. Then, the trichlorosilane needs to be purified by chlorosilane purification process, and the purified trichlorosilane is used to reduce the polycrystalline silicon in the reduction furnace. In the process of preparing chlorosilane by cold hydrogenation, a large amount of chlorosilane slurry is produced, which mainly contains silicon tetrachloride, trichlorosilane, silicon copper powder, silicon-containing polymers and other solid impurities. In the prior art, the chlorosilane slurry is treated by hydrolysis and other methods. This treatment method has low chlorosilane recovery rate, large alkali consumption, and causes environmental pollution. It not only increases the production cost of enterprises and causes a large amount of resource waste, but also causes environmental pollution. Therefore, it is necessary to convert the chlorosilane slurry into a useful resource. In recent years, the environmental protection pressure is increasing, and the price of polycrystalline silicon is low. To achieve the goal of "harmless, reduction and resource", it is still a technical problem that restricts the development of domestic polycrystalline silicon industry. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a method and system for recycling chlorosilane slurry, which can recycle chlorosilane from chlorosilane slurry and convert it into a useful resource to obtain a silicate product.

[0004] To solve the above technical problems, the present application adopts the following technical scheme:

[0005] A method for recycling chlorosilane slurry, comprising the following steps:

[0006] Step 1: solid-liquid separation of chlorosilane slurry to obtain crude chlorosilane liquid;

[0007] Step 2: crude chlorosilane is reacted with ethanol to obtain crude silicate after purification;

[0008] Step 3: purification of crude silicate to obtain silicate product.

[0009] Preferably, the step 1: solid-liquid separation of chlorosilane slurry to obtain crude chlorosilane liquid, specifically comprising the following steps:

[0010] S1.1: The chlorosilane slurry is treated by cooling and pressure reduction flash evaporation to obtain chlorosilane flash steam and a chlorosilane solid-liquid mixture; the chlorosilane slurry before treatment is in a high-temperature and high-pressure state, and a higher temperature can cause part of the chlorosilane slurry to flash evaporate, and the cooling and pressure reduction treatment can reduce the amount of chlorosilane evaporation, and at the same time, the design temperature of the container for the solid-liquid separation of the chlorosilane slurry is 100℃, and the design pressure is 0.7MPa, and the design temperature and design pressure of the container are lower than the temperature and pressure of the chlorosilane slurry before treatment, so the cooling and pressure reduction treatment can also ensure the safety of subsequent operations.

[0011] S1.2: The chlorosilane solid-liquid mixture is subjected to solid-liquid separation to obtain a crude chlorosilane liquid and a solid residue;

[0012] S1.3: The chlorosilane flash steam is condensed to obtain a chlorosilane condensate.

[0013] Preferably, in step S1.1, the temperature range of the chlorosilane slurry cooling and pressure reduction treatment is from 145 to 155℃ cooling to 50 to 60℃, the pressure range is from 1.4 to 1.6MPa pressure reduction to 0.01 to 0.7MPa, and the treatment time is 0.33 to 2h.

[0014] Preferably, in step S1.2, it further includes step S1.2.1: the solid residue is washed with a detergent, and a chlorosilane-containing washing liquid is recovered; the number of washing times can be one or more, and the detergent is used to dissolve and wash down the residual chlorosilane in the solid residue; the detergent used in step S1.2.1 is toluene; toluene is used as the detergent because toluene has a high boiling point and a small amount of volatilization, and can be recycled and reused during the washing process.

[0015] Preferably, in step S1.3, the condensation temperature is 20 to 25℃, and the condensation time is 0.002 to 0.5h.

[0016] Preferably, in step 2, the chlorosilane reacts with ethanol to generate a crude silicate, which specifically includes the following steps:

[0017] S2.1: The crude chlorosilane liquid obtained in step S1.2, the chlorosilane-containing washing liquid recovered in step S1.2.1, and the chlorosilane condensate obtained in step S1.3 are subjected to distillation treatment to obtain purified chlorosilane;

[0018] S2.2: The purified chlorosilane is reacted with ethanol to prepare a crude silicate.

[0019] Preferably, in step S2.1, the distillation column still temperature range is 160 to 165℃, and the column top temperature range is 69 to 75℃; the distillation pressure is 0.05 to 0.07MPa; and the distillation time is 1 to 3h.

[0020] Preferably, in step S2.2, the purified chlorosilane and ethanol are reacted in a reaction column, wherein the mass ratio of the purified chlorosilane to ethanol is 0.72-0.76:1, the temperature at the top of the reaction column is 33-37℃, the temperature at the bottom of the reaction column is 100-105℃, the pressure at the top of the reaction column is 57-63 KPa, the liquid level at the bottom of the reaction column accounts for 45-55% of the volume of the bottom of the reaction column, and the ethanol used in the reaction is anhydrous ethanol.

[0021] Preferably, in step 3, the crude silicate is purified to obtain a silicate product, specifically including the following steps:

[0022] S3.1: Impurities in the crude silicate are removed by negative pressure deacidification to obtain a silicate, wherein the principle of negative pressure deacidification is that a deacidification column, which is a distillation column, can reduce the temperature at the bottom of the column under negative pressure, so that substances can be separated according to the different boiling points of the components, wherein ethanol and hydrogen chloride are vaporized into gas, while the silicate remains liquid, thereby removing trace amounts of hydrogen chloride from the silicate and improving the quality of the silicate.

[0023] S3.2: The silicate product is obtained by decolorization, wherein decolorization is used to remove colored metal impurities to further improve the quality of the silicate.

[0024] Preferably, in step S3.1, the negative pressure used is in the range of -90 to -60 KPa, and the negative pressure deacidification time is 0.16-0.5 h.

[0025] Preferably, in step S3.2, the silicate is treated by decolorization using a filter, and the principle of filter decolorization is to use an adsorbent to adsorb colored metal impurities in the silicate, wherein the commonly used adsorbent is activated carbon; the colored metal impurities mainly include iron metal impurities, specifically including ferric chloride and elemental iron.

[0026] The present application also provides a system for recycling chlorosilane slurry, comprising a preliminary recovery device and a silicate production device.

[0027] The preliminary recovery device comprises a separator for solid-liquid separation of the chlorosilane slurry to obtain a crude chlorosilane liquid, wherein the separator uses a solid-liquid separation method such as centrifugation, natural sedimentation or filtration.

[0028] The silicate production device comprises a reaction column, a deacidification column and a filter:

[0029] The reaction column is connected to the separator and is used for the reaction of the crude chlorosilane separated by the preliminary recovery device and ethanol to generate a crude silicate;

[0030] The deacidification tower is used to remove acidic substances in the reaction product of the reaction tower;

[0031] The filter is used to decolorize the crude silicate after removing the acidic substances.

[0032] Preferably, the preliminary recovery device further comprises a mixing kettle, a flash vapor condenser and a crude chlorosilane tank,

[0033] The mixing kettle is used to perform low-pressure cooling treatment on the chlorosilane slurry to obtain chlorosilane flash vapor and chlorosilane solid-liquid mixture;

[0034] The flash vapor condenser is used to condense the chlorosilane flash vapor output by the mixing kettle to obtain chlorosilane condensate;

[0035] The crude chlorosilane tank is used to collect the chlorosilane condensate output by the flash vapor condenser and the crude chlorosilane liquid separated in the separator, and the chlorosilane liquid collected by the crude chlorosilane tank is delivered to the reaction tower of the silicate production device;

[0036] The chlorosilane solid-liquid mixture is delivered into the separator at the kettle bottom of the mixing kettle.

[0037] Preferably, the silicate production device further comprises a second hydrolysis kettle, which is connected after the filter and used to provide a place for producing different specifications of silicate products.

[0038] Preferably, the system for recycling the chlorosilane slurry further comprises a washing device, which comprises a washer, a chlorosilane tower and a centrifugal machine, the washer is connected with the solid residue liquid discharge port of the separator and used to wash the chlorosilane adhered to the solid residue;

[0039] The centrifugal machine is used to perform solid-liquid separation on the chlorosilane slurry from which part of the chlorosilane has been removed;

[0040] The chlorosilane tower is used to collect the chlorosilane liquid washed by the washer and the chlorosilane liquid separated by the centrifugal machine during the solid-liquid separation, and separate the chlorosilane liquid, and the chlorosilane separated at the top of the chlorosilane tower is recycled to the reaction tower to synthesize silicate, wherein the chlorosilane tower is used to separate the washing agent in the chlorosilane liquid.

[0041] Preferably, the washing device further comprises a washing liquid tower and a washing liquid tank,

[0042] The washing liquid tower is used to separate the washing liquid and heavy components discharged from the kettle of the chlorosilane tower;

[0043] The washing liquid tank is used to collect the washing liquid separated in the washing liquid tower.

[0044] Preferably, the silicate production device further comprises an absorption tower, a gas-liquid separator and a hydrogen chloride buffer tank; the absorption tower is used to collect the gas phase discharged from the reaction tower and absorb the chloroethane in the gas phase;

[0045] The gas-liquid separator is used to collect the hydrogen chloride in the gas discharged from the top of the absorption tower and deliver it to the hydrogen chloride buffer tank for use in the polysilicon production system.

[0046] Preferably, the silicate production device further comprises a regeneration tower and a first reaction hydrolysis kettle; the chlorosilane liquid in the absorption tower absorbs the chloroethane as the kettle liquid to enter the regeneration tower, and the regeneration tower is used to remove the chloroethane in the chlorosilane liquid obtained from the kettle of the absorption tower, so as to recycle the chlorosilane liquid.

[0047] The first reaction hydrolysis kettle is used as a reactor for the reaction of the chloroethane obtained from the top of the regeneration tower with the sodium hydroxide solution to generate ethanol.

[0048] The method for recycling the chlorosilane slurry in the present application can recycle the chlorosilane in the chlorosilane slurry and convert it into a useful resource to obtain a silicate product, so as to reduce resource waste.

[0049] The system for recycling the chlorosilane slurry in the present application can realize the above-mentioned method for recycling the chlorosilane slurry, and can obtain different types of silicate products, such as Si-28 products, Si-32 products or Si-40 products, according to industrial requirements; in addition, the byproduct hydrogen chloride in the prepared silicate product is effectively recycled by the silicate production device and can be used again in the polysilicon production. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The flow chart of the recycling of the chlorosilane slurry in the embodiments of the present application.

[0051] In the figure: 1-mixing kettle; 2-flash vapor condenser; 3-separator; 4-secondary separator; 5-rough chlorosilane tank; 6-distillation column; 7-reaction column; 8-deacidification column; 9-filter; 10-Si-28 product storage tank; 11-Si-28 tank filling unit; 12-second hydrolysis kettle; 13-Si-32 storage tank; 14-Si-32 tank filling unit; 15-Si-40 storage tank; 16-Si-40 tank filling unit; 17-95% ethanol storage tank; 18-anhydrous ethanol storage tank; 19-absorption column; 20-regeneration column A; 21-regeneration column B; 22-first hydrolysis kettle; 23-gas-liquid separator; 24-hydrogen chloride buffer tank; 25-heavy component tank; 26-washer; 27-secondary washer; 28-chlorosilane column; 29-washing liquid column; 30-washing liquid tank; 31-centrifuge. DETAILED DESCRIPTION

[0052] The technical solutions in the application will be described clearly and completely below in combination with the drawings in the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the application.

[0053] The application provides a method for recycling chlorosilane slurry, comprising the following steps:

[0054] Step 1: solid-liquid separation of chlorosilane slurry to obtain rough chlorosilane liquid;

[0055] Step 2: rough chlorosilane reacts with ethanol to generate rough silicate after purification;

[0056] Step 3: purification of rough silicate to obtain silicate product.

[0057] The application also provides a system for recycling chlorosilane slurry, comprising a preliminary recovery device and a silicate production device;

[0058] The preliminary recovery device comprises a separator, which is used for solid-liquid separation of chlorosilane slurry to obtain rough chlorosilane liquid;

[0059] The silicate production device comprises a reaction column, a deacidification column and a filter:

[0060] The reaction column is used for reaction of the rough chlorosilane separated by the preliminary recovery device with the ethanol to generate rough silicate;

[0061] The deacidification column is used for removing acidic substances in the reaction product rough silicate of the reaction column;

[0062] The filter is used for decoloring treatment of the crude silicate after removing acidic substances.

[0063] Embodiment 1

[0064] The embodiment provides a method for recycling chlorosilane slurry, comprising the following steps:

[0065] Step 1: solid-liquid separation of chlorosilane slurry to obtain crude chlorosilane liquid;

[0066] In step 1, the solid-liquid separation of the chlorosilane slurry to obtain the crude chlorosilane liquid specifically comprises the following steps:

[0067] S1.1: cooling and pressure reduction treatment of the chlorosilane slurry to obtain chlorosilane flash steam and a chlorosilane solid-liquid mixture; specifically, the chlorosilane slurry generated in the polysilicon production process is cooled and pressure reduced in the embodiment, wherein the temperature is cooled from 150 DEG C to 50-60 DEG C, the temperature is cooled to 50 DEG C in the embodiment, the pressure is reduced from 1.5 MPa to 0.07 MPa or below, and the treatment time is 1 h.

[0068] S1.2: solid-liquid separation of the chlorosilane solid-liquid mixture to obtain a crude chlorosilane liquid and a solid residue; wherein the solid-liquid separation can be carried out by the methods of sedimentation and standing, centrifugation or filtration, and the embodiment adopts the method of centrifugation for solid-liquid separation. In step S1.2, step S1.2.1: washing the solid residue and recovering the washing liquid is further included; and the washing agent used in step S1.2.1 is toluene; in the embodiment, the step S1.2.1 is washed twice by toluene.

[0069] S1.3: condensation of the chlorosilane flash steam to obtain a chlorosilane condensate, the condensation temperature is 20 DEG C, and the condensation time is 0.002 h.

[0070] Step 2: reaction of chlorosilane with ethanol to generate crude silicate;

[0071] In step 2, the reaction of chlorosilane with ethanol to generate crude silicate (i.e. crude silicon ethylate) specifically comprises the following steps:

[0072] S2.1: distillation treatment of the crude chlorosilane liquid obtained in step S1.2, the washing liquid containing chlorosilane recovered in step S1.2.1 and the chlorosilane condensate obtained in step S1.3 to obtain purified chlorosilane; wherein the distillation column still temperature is 160 DEG C, the column top temperature is 75 DEG C, the distillation pressure is 0.05 MPa, and the distillation time is 1 h.

[0073] S2.2: reacting the purified chlorosilane with ethanol to prepare a crude silicate (i.e., crude ethyl silicate); in step 2.2, the purified chlorosilane is reacted with ethanol in a reaction column, wherein the mass ratio of the purified chlorosilane to ethanol is 0.72:1, the temperature at the top of the reaction column ranges from 33℃, the temperature at the bottom of the reaction column is 105℃, the pressure at the top of the reaction column is 57 KPa, the volume fraction of the liquid level at the bottom of the reaction column in the volume of the reaction column is 55%, and the ethanol used in the reaction is anhydrous ethanol.

[0074] Step 3: purifying the crude silicate to obtain a silicate product;

[0075] Step 3: purifying the crude silicate (i.e., crude ethyl silicate) to obtain a silicate (i.e., ethyl silicate) product, specifically including the following steps:

[0076] S3.1: removing impurities from the crude silicate by negative pressure deacidification, such as removing trace amounts of hydrogen chloride from the crude silicate, and obtaining a silicate; in step S3.1, the negative pressure used is -90 KPa, and the reaction time is 0.5 h.

[0077] S3.2: obtaining a silicate product by decolorization; in step S3.2, the silicate is treated by decolorization using a filter, and in this embodiment, a filter of model 7HCF4-E-20180616-01 produced by Jiangyin Xinyao Photovoltaic New Material Co., Ltd. is used, and the decolorization treatment is used to remove colored metal impurities in the silicate, wherein the colored metal impurities are mainly iron metal impurities, specifically ferric chloride and elemental iron.

[0078] Example 2:

[0079] The present embodiment provides a method for recycling chlorosilane slurry, which includes the following steps:

[0080] Step 1: solid-liquid separation of chlorosilane slurry to obtain a crude chlorosilane liquid;

[0081] In step 1, the solid-liquid separation of the chlorosilane slurry to obtain a crude chlorosilane liquid specifically includes the following steps:

[0082] S1.1: cooling and depressurizing the chlorosilane slurry to obtain chlorosilane flash steam and a chlorosilane solid-liquid mixture; specifically, in this embodiment, the chlorosilane slurry generated during the production of polysilicon is cooled and depressurized, wherein the temperature is cooled from 155℃ to 50-60℃, in this embodiment, the temperature is cooled to 60℃, the pressure is reduced from 1.6 MPa to below 0.01 MPa, and the treatment time is 2 h.

[0083] S1.2: solid-liquid separation of the chlorosilane solid-liquid mixture to obtain a crude chlorosilane liquid and a solid residue; the solid-liquid separation can be performed by static setting, centrifugation or filtration; in this embodiment, the solid-liquid separation is performed by static setting. In step S1.2, there is also step S1.2.1: washing the solid residue and recovering the washing liquid; the washing agent used in step S1.2.1 is toluene, and in this embodiment, step S1.2.1 is performed once by toluene washing.

[0084] S1.3: flash vaporization and condensation of the chlorosilane to obtain a chlorosilane condensate, the condensation temperature is 25℃, and the condensation time is 0.5h.

[0085] Step 2: reaction of chlorosilane with ethanol to obtain a crude silicate (i.e. crude ethyl silicate);

[0086] In step 2, the reaction of chlorosilane with ethanol to obtain a crude silicate includes the following steps:

[0087] S2.1: distillation of the crude chlorosilane liquid obtained in step S1.2, the chlorosilane-containing washing liquid recovered in step S1.2.1 and the chlorosilane condensate obtained in step S1.3 to obtain purified chlorosilane; the distillation is performed at a column still temperature of 165℃, a column top temperature of 69℃, a distillation pressure of 0.07MPa and a distillation time of 3h.

[0088] S2.2: reaction of the purified chlorosilane with ethanol to prepare a crude silicate (i.e. crude ethyl silicate); in step 2.2, the purified chlorosilane and ethanol are reacted in a reaction column, the mass ratio of the purified chlorosilane to ethanol is 0.76:1, the reaction column top temperature is in the range of 37℃, the reaction column still temperature is 103℃, the reaction column top pressure is 60KPa, the reaction column still liquid level accounts for 45% of the reaction column still volume, and the ethanol used in the reaction is anhydrous ethanol.

[0089] Step 3: purification of the crude silicate to obtain a silicate product;

[0090] Step 3: purification of the crude silicate (i.e. crude ethyl silicate) to obtain a silicate (i.e. ethyl silicate) product, which includes the following steps:

[0091] S3.1: removal of impurities from the crude silicate by negative pressure deacidification, such as removal of trace amounts of hydrogen chloride from the crude silicate, to obtain a silicate; in step S3.1, the negative pressure is in the range of -60KPa, and the reaction time is 0.3h.

[0092] S3.2: The silicon ester product is obtained by decolorization; in step S3.2, the silicon ester is subjected to decolorization treatment by using a filter, and in the embodiment, a filter of model 7HCF4-E-20180616-01 produced by Jiangyin Xiyao Photovoltaic New Material Co., Ltd. is used, and the decolorization treatment is used to remove colored metal impurities in the silicon ester, wherein the colored metal impurities are mainly iron metal impurities, specifically ferric chloride and elemental iron.

[0093] Embodiment 3:

[0094] The embodiment provides a method for recycling chlorosilane slurry, comprising the following steps:

[0095] Step 1: solid-liquid separation of chlorosilane slurry to obtain a crude chlorosilane liquid;

[0096] In step 1, the solid-liquid separation of the chlorosilane slurry to obtain the crude chlorosilane liquid specifically comprises the following steps:

[0097] S1.1: cooling and pressure reduction treatment of the chlorosilane slurry to obtain chlorosilane flash steam and a chlorosilane solid-liquid mixture; specifically, the chlorosilane slurry generated in the polysilicon production process is cooled and pressure reduced in the embodiment, wherein the temperature is cooled from 145°C to 50-60°C, the temperature is cooled to 55°C in the embodiment, the pressure is reduced from 1.4 MPa to 0.6 MPa or less, and the treatment time is 0.33 h.

[0098] S1.2: solid-liquid separation of the chlorosilane solid-liquid mixture to obtain a crude chlorosilane liquid and a solid residue; wherein the solid-liquid separation can be performed by sedimentation and standing, or by centrifugation, and similarly, the solid-liquid separation can also be performed by filtration, and in the embodiment, the solid-liquid separation is performed by filtration. In step S1.2, step S1.2.1 is further included: the solid residue is washed, and the washed liquid is recovered; and the washing agent used in step S1.2.1 is toluene; in the embodiment, the solid residue is washed three times by toluene.

[0099] S1.3: condensation of the chlorosilane flash steam to obtain a chlorosilane condensate, the condensation temperature is 23°C, and the condensation time is 0.3 h.

[0100] Step 2: reaction of chlorosilane with ethanol to generate a crude silicon ester;

[0101] In step 2, the reaction of chlorosilane with ethanol to generate a crude silicon ester (i.e., a crude silicon ethyl ester) comprises the following steps:

[0102] S2.1: The crude chlorosilane liquid obtained in step S1.2, the chlorosilane-containing washing liquid recovered in step S1.2.1, and the chlorosilane condensate obtained in step S1.3 are subjected to distillation to obtain purified chlorosilane; wherein, the temperature of the distillation column bottom is 163℃, the temperature of the column top is 70℃, the distillation pressure is 0.06MPa, and the distillation time is 2h.

[0103] S2.2: The purified chlorosilane is reacted with ethanol to prepare crude silicate ester; in step 2.2, the purified chlorosilane and ethanol are reacted in a reaction tower, wherein the mass ratio of purified chlorosilane to ethanol is 0.75:1, the temperature at the top of the reaction tower is 35℃, the temperature at the bottom of the tower is 100℃, the pressure at the top of the reaction tower is 63KPa, the liquid level at the bottom of the reaction tower accounts for 50% of the volume fraction of the bottom of the reaction tower, and the ethanol used in the reaction is anhydrous ethanol.

[0104] Step 3: Purify the crude silicate ester to obtain the silicate ester product;

[0105] Step 3 involves purifying crude silicate ester (i.e., crude ethyl silicate) to obtain the silicate ester product, specifically including the following steps:

[0106] S3.1: Impurities in crude silicate ester are removed by negative pressure deacidification, such as removing trace amounts of hydrogen chloride from the crude silicate ester to obtain silicate ester; in step S3.1, the negative pressure range is -75 kPa and the reaction time is 0.16 h.

[0107] S3.2: The silicate ester product is obtained by decolorization. In step S3.2, the silicate ester is decolorized using a filter. In this embodiment, a filter of model 7HCF4-E-20180616-01 produced by Jiangyin Xinyao Photovoltaic New Material Co., Ltd. is used. The decolorization process is used to remove colored metallic impurities from the silicate ester. The colored metallic impurities are mainly iron metal impurities, specifically ferric chloride and elemental iron.

[0108] Example 4:

[0109] This embodiment provides a system for recycling and reusing chlorosilane slurry, such as... Figure 1As shown, the system includes a preliminary recovery unit and a silicate ester production unit. The preliminary recovery unit includes a separator 3, which is used to separate the solid and liquid components of the chlorosilane slurry to obtain crude chlorosilane liquid. The solid-liquid separation method used in the separator 3 can be centrifugation, settling, or filtration. In actual operation, settling is used for separation, with a settling time of 0.5 to 2 hours, which can be 0.5 hours, 1 hour, or 2 hours. The silicate ester production unit includes a reaction tower 7, a deacidification tower 8, and a filter 9. The reaction tower 7 is used to react the crude chlorosilane separated from the preliminary recovery unit with ethanol to produce crude silicate ester. The deacidification tower 8 is used to remove acidic substances from the crude silicate ester produced by the reaction tower 7, such as removing trace amounts of hydrogen chloride. The filter 9 is used to decolorize the crude silicate ester after the acidic substances have been removed.

[0110] In this embodiment, the preliminary recovery device further includes a mixing vessel 1, a flash vapor condenser 2, and a crude chlorosilane tank 5. The mixing vessel 1 is used to cool and depressurize the chlorosilane slurry to obtain chlorosilane flash vapor and a chlorosilane solid-liquid mixture. The flash vapor condenser 2 is used to condense the chlorosilane flash vapor output from the mixing vessel 1 to obtain chlorosilane condensate. The crude chlorosilane tank 5 is used to collect the chlorosilane condensate output from the flash vapor condenser 2 and the crude chlorosilane liquid separated by the separator 3. The chlorosilane liquid collected in the crude chlorosilane tank 5 is transported to the reaction tower of the silicate ester production unit. The chlorosilane solid-liquid mixture is transported from the bottom of the mixing vessel to the separator 3.

[0111] In this embodiment, the silicate ester production apparatus further includes a second hydrolysis reactor 12, which is connected after the filter 9 and is used to produce silicate ester products of different specifications. The silicate ester products can be Si-28 products, Si-32 products or Si-40 products.

[0112] In this embodiment, the system for recycling and reusing chlorosilane slurry further includes a washing device, which includes a scrubber 26, a chlorosilane tower 28, and a centrifuge 31. The scrubber 26 is used to wash off the chlorosilane adhering to the solid residue; the centrifuge 31 is used to perform solid-liquid separation on the chlorosilane slurry after removing part of the chlorosilane slurry liquid; the chlorosilane tower 28 is typically a separation tower, which separates the components based on their different boiling points, separating the chlorosilane slurry liquid collected from the scrubber 26 and / or centrifuge 31, and returning the chlorosilane obtained from the top of the chlorosilane tower 28 to the slurry. The product is collected in reaction tower 7 to synthesize silicate esters. The temperature range of the top of the chlorosilane tower 28 is 70-78℃, and the temperature range of the bottom of the tower is 125-135℃. That is, the temperature of the top of the chlorosilane tower 28 can be 70℃, 74℃, or 78℃, etc., and the temperature of the bottom of the tower can be 125℃, 130℃, or 135℃, etc. In this embodiment, the temperature of the top of the chlorosilane tower 28 is 75℃, and the temperature of the bottom of the tower is 132℃. The separation reaction time is 0.5-4h, that is, the reaction time can be 0.5h, 2h, or 4h, etc. In this embodiment, the reaction time is 2h.

[0113] In this embodiment, the washing device further includes a washing liquid tower 29 and a washing liquid tank 30. The washing liquid tower 29 is used to separate the washing liquid discharged from the bottom of the chlorosilane tower 28 from the heavy components. Typically, the washing liquid tower 29 is a separation tower that separates the washing liquid from the heavy components based on the difference in boiling points. The top temperature range of the washing liquid tower 29 during the separation process is 110–120°C, meaning the top temperature of the washing liquid tower 29 can be 110°C, 115°C, or 120°C, etc., and the bottom temperature range is 145–150°C. The temperature of the bottom of the washing liquid tower is 145°C, 149°C, or 155°C, etc. In this embodiment, the temperature at the top of the washing liquid tower 29 is 114°C and the temperature at the bottom of the tower is 149°C. The reaction time is 0.16 to 3 hours, that is, the reaction time can be 1 hour, 2 hours, or 3 hours, etc. In this embodiment, the reaction time is 2 hours. The washing liquid tank 30 is used to collect the washing liquid separated from the washing liquid tower 29 and to recycle the washing liquid. The heavy components separated from the washing liquid tower 29 are then transported to the heavy component tank 25 after cooling.

[0114] In this embodiment, the silicate ester production apparatus further includes an absorption tower 19, a gas-liquid separator 23, and a hydrogen chloride buffer tank 24; the absorption tower 19 is used to collect the gas phase in the reaction tower 7 and absorb chloroethane in the gas phase; the gas-liquid separator 23 is used to collect hydrogen chloride in the gas discharged from the top of the absorption tower 19 and transport it to the hydrogen chloride buffer tank 24 for use by the polysilicon production system.

[0115] In this embodiment, the silicate ester production apparatus further includes a regeneration tower and a first reaction hydrolysis vessel 22; wherein, the chlorosilane liquid in the absorption tower 19 absorbs chloroethane as the bottom liquid and enters the regeneration tower, the regeneration tower is used to remove chloroethane from the chlorosilane liquid obtained from the bottom of the absorption tower 19, so that the chlorosilane liquid can be recycled; the first reaction hydrolysis vessel 22 is used to provide a place for the chloroethane obtained at the top of the regeneration tower to react with sodium hydroxide solution to generate ethanol.

[0116] In this embodiment, the chlorosilane slurry discharged during the polysilicon production process is specifically described with a pressure of 1.5 MPaG and a temperature of 150°C. The solid content (wt%) of the chlorosilane slurry is as follows: silicon powder 2%, cuprous chloride 1.51%; silicon tetrachloride (SiCl4): 87%, trichlorosilane (SiHCl3): 1.49%, and disilicide hexachloride (Si2Cl6): 8%. First, the chlorosilane slurry is transported to mixing vessel 1 via pipeline. Mixing vessel 1 is equipped with a stirrer and a cooling jacket. The stirrer is used to ensure uniform mixing of the chlorosilane slurry and prevent solid phase deposition at the bottom of mixing vessel 1. The cooling jacket is used to cool mixing vessel 1, controlling the temperature of the chlorosilane slurry at 50-60℃, such as 56℃. At this temperature, not only can the evaporation rate of chlorosilane be reduced (chlorosilane has a high solid content), but the stirring also keeps the slurry uniform, preventing solid phase deposition at the bottom of the vessel and clogging of the pipeline. In addition, since the design temperature of mixing vessel 1 is 180℃ and the design pressure is 1.6MPa, while the design temperature of separator 3 is 100℃ and the design pressure is 0.7MPa, the design temperature and design pressure of separator 3 are both lower than the pressure and temperature of untreated chlorosilane slurry. Therefore, cooling and depressurization treatment can also ensure operational safety. The operating pressure of mixing vessel 1 is controlled at 0.07 MPaG. Due to the significant pressure drop, some chlorosilane liquid in the chlorosilane slurry flashes, forming chlorosilane flash vapor. The generated chlorosilane flash vapor is condensed by flash vapor condenser 2 to obtain chlorosilane condensate, which is then recovered to crude chlorosilane tank 5. The condensation temperature is 20-25℃, and the condensation time is 0.002-0.5h. In this embodiment, the condensation temperature is 22℃, and the time is 0.1h. The slurry remaining after flashing in mixing vessel 1 enters separator 3 for solid-liquid separation. Separator 3 is a static separator. In this embodiment, separator 3 is a static separator of model XHR18-171 manufactured by Chengdu Xinhuarong Chemical Equipment Manufacturing Co., Ltd. The separated liquid phase enters secondary separator 4 through the overflow port for further separation. Secondary separator 4 is usually a static separator. In this embodiment, secondary separator 4 is a static separator of model XHR18-175 manufactured by Chengdu Xinhuarong Chemical Equipment Manufacturing Co., Ltd. After the material inside the secondary separator 4 is allowed to stand for 0.5-3 hours, the liquid phase overflows into the crude chlorosilane tank 5. In this embodiment, the material inside the secondary separator 4 is allowed to stand for 2 hours. The bottom material in the separator 3 and the secondary separator 4 after overflow mainly consists of solid silicon copper powder and some chlorosilane liquid. The bottom material in the separator 3 and the secondary separator 4 enters the scrubber 26 for washing to remove the chlorosilane liquid adhering to the solid residue (solid silicon copper powder). In the above operation, through solid-liquid separation, ~80% of the chlorosilane (mainly silicon tetrachloride, with a small amount of trichlorosilane) in the chlorosilane slurry is separated, and the purity of silicon tetrachloride can reach 98.5 wt%.

[0117] The crude chlorosilane tank 5 mainly contains liquid chlorosilane, along with trace amounts of solids and some heavy components. The heavy components primarily include silicon tetrachloride, trichlorosilane, and disilicide hexachloride. The liquid chlorosilane in the crude chlorosilane tank 5 is transferred to distillation column 6, where it undergoes rectification distillation. In this embodiment, the distillation column 6 used is a CJ18280 model manufactured by NEL Energy Equipment Co., Ltd., and the temperature range of the distillation column reboiler is 160-165℃. The temperature range at the top of the column is 69-75℃, and the distillation time is 1-3 hours. In this embodiment, the temperature at the bottom of the column is 164℃, the temperature at the top of the column is 70℃, and the distillation time is 2 hours. The purified chlorosilane gas is recovered at the top of the distillation column 6, while the bottom of the column contains the heavy component. The heavy component from the bottom of the column enters the heavy component tank 25 and is then sent to the existing hydrolysis treatment system for processing. The existing hydrolysis treatment system is a slurry hydrolysis device, which includes a slurry stirring tank and a hydrolyzer. The chlorosilane gas recovered at the top of the distillation column 6 enters the reaction column 7 (where a chemical reaction is carried out by reactive distillation) as a raw material to react with anhydrous ethanol from the anhydrous ethanol storage tank 18 to prepare silicate ester (i.e., ethyl silicate). The temperature at the top of reaction tower 7 is controlled at 33-37℃, the temperature at the bottom of the tower is controlled at 100-105℃, the pressure at the top of the tower is controlled at 57-63 kPa, and the liquid level at the bottom of the tower occupies 45-55% of the tower's volume. The reaction is carried out with a mass ratio of chlorosilane gas to anhydrous ethanol of 0.72-0.76:1 to obtain silicate esters. In this embodiment, the mass ratio of chlorosilane gas to anhydrous ethanol is 0.75:1. Since approximately 80% of the chlorosilane is separated from the purified chlorosilane slurry, and the main component is silicon tetrachloride with a purity of 98.5 wt%, the reaction of chlorosilane gas and anhydrous ethanol can be considered as the preparation of ethyl silicate from silicon tetrachloride and anhydrous ethanol. However, a large amount of hydrogen chloride is generated as a byproduct in this chemical reaction, and a small amount of chloroethane is produced by the reaction of hydrogen chloride with ethanol. The byproducts hydrogen chloride and the small amount of chloroethane need to be removed from the reaction system. The bottom material of reaction tower 7 contains ethyl silicate, ethanol, and a small amount of hydrogen chloride. The bottom material of reaction tower 7 then enters deacidification tower 8. Deacidification tower 8 operates under negative pressure to remove trace amounts of hydrogen chloride from the silicate ester, thereby improving the quality of ethyl silicate. Under normal circumstances, the negative pressure used in deacidification tower 8 is -90 to -60 kPa, and the reaction time is 0.16-0.5 h. In this embodiment, the negative pressure is -75 kPa, and the reaction time is 0.3 h.After deacidification by deacidification tower 8, ethyl silicate is collected from the bottom of deacidification tower 8 and sent to filter 9 for decolorization. Decolorization is mainly used to remove colored metallic impurities. After decolorization, Si-28 product is obtained and transported to Si-28 product storage tank 10. The final Si-28 product has an orthosilicate content (calculated as silicon dioxide) of up to 28 wt%. After meeting the external sales conditions, it is automatically packaged into drums by Si-28 drum unit 11 and then sold externally. To increase product variety and meet customer needs, the silicate ester production unit in the system for recycling and reusing chlorosilane slurry in this embodiment also includes a second hydrolysis reactor. By adding different proportions of tetraethyl orthosilicate and 95% ethanol (from a 95% ethanol storage tank) to the second hydrolysis reactor 12, Si-32 and Si-40 products can be obtained respectively. Specifically, the ratio of tetraethyl orthosilicate to 95% ethanol added to obtain Si-32 product is 1.4 to 1.6:1, the reaction temperature is 75 to 85°C, and the reaction time is 0.16 to 1 hour. The ratio of tetraethyl orthosilicate to 95% ethanol added to obtain Si-40 product is 0.7 to 0.75:1, and the reaction temperature is 75 to 85°C, with a reaction time of 0.16 to 1 hour. Finally, the Si-32 product enters the Si-32 storage tank 13, and the Si-40 product enters the Si-40 storage tank 15. The Si-32 and Si-40 products are then packaged and sold through the Si-32 packaging unit 14 and the Si-40 packaging unit 16, respectively.

[0118] In addition, the main gaseous components in reaction tower 7 are hydrogen chloride and chloroethane. The gaseous phase of reaction tower 7 enters absorption tower 19, where chlorosilane liquid fed by distillation tower 6 is introduced. Since chloroethane is easily soluble in chlorosilane liquid, while hydrogen chloride gas has low solubility in chlorosilane liquid, the chlorosilane liquid absorbs chloroethane and enters the bottom of absorption tower 19. Meanwhile, the gaseous hydrogen chloride is discharged from the top of absorption tower 19 to gas-liquid separator 23. Gas-liquid separator 23 is mainly used to separate hydrogen chloride gas and chlorosilane liquid to obtain purified hydrogen chloride gas. The separated hydrogen chloride gas enters hydrogen chloride buffer tank 24 for use in the polysilicon production system. The chlorosilane liquid after removing hydrogen chloride gas mainly consists of silicon tetrachloride with a mass fraction of 98.5% and trichlorosilane with a mass fraction of 1.19%. The bottom liquid in absorption tower 19 enters regeneration tower A 20. The main components of the bottom liquid in regeneration tower A 20 are chlorosilane liquid, chloroethane impurities, hydrogen chloride impurities, and ethanol impurities. Regeneration tower A 20 removes hydrogen chloride impurities from the chlorosilane liquid through distillation. Subsequently, the bottom liquid of regeneration tower A 20 is discharged to regeneration tower B 21 to remove chloroethane and ethanol impurities from the chlorosilane liquid. The mass fraction of chloroethane in the chlorosilane liquid discharged from regeneration tower A 20 to regeneration tower B 21 is 1.8%. The principle of removing chloroethane from the chlorosilane liquid in regeneration tower B 21 is based on the different boiling points of each component, separating components with different boiling points through steam heating. Subsequently, regeneration tower B... The chlorosilane liquid in the bottom of regeneration tower B21 can be returned to absorption tower 19 for continued recycling to absorb chloroethane. The chlorosilane liquid in the bottom of regeneration tower B21 includes 98.5% silicon tetrachloride, 1.19% trichlorosilane, 3.1E-06% disilicide hexachloride, and 7.17E-12% toluene. Chloroethane, discharged from the top of regeneration tower B21, is recovered and enters the first hydrolysis reactor 22. A 5% sodium hydroxide solution is introduced into the first hydrolysis reactor 22 to hydrolyze the chloroethane. The resulting gaseous ethanol is condensed and recycled to anhydrous ethanol storage tank 18 for reuse. The waste liquid in the first hydrolysis reactor 22 is discharged to the polysilicon production system wastewater treatment device for treatment.

[0119] In addition, before the solid material enters the scrubber 26, a certain proportion of detergent (such as toluene) is first added to the scrubber 26 according to the amount of solid material. The mass ratio of detergent to solid material is usually 4.9-5.1:1. The detergent is used to dissolve and wash away the chlorosilanes adhering to the solid residue. After the material is washed and separated by the detergent, the liquid phase overflows into the secondary scrubber 27. After settling in the secondary scrubber 27, the liquid phase is recovered by overflow and transported to the chlorosilane tower 28. Separation is carried out in chlorosilane tower 28, where the top temperature is 75℃, the bottom temperature is 132℃, and the distillation time is 0.5–4 h. After the reaction, the chlorosilane separated from the top of chlorosilane tower 28 is recovered to reaction tower 7 to synthesize silicate esters. The bottom material of chlorosilane tower 28 enters washing liquid tower 29 for separation. The bottom material of chlorosilane tower 28 mainly consists of washing liquid and heavy components. To separate the washing liquid and heavy components, the bottom material of chlorosilane tower 28 is conveyed to washing liquid tower 29. The washing liquid tower 29 uses distillation to separate the two components. The top temperature of the distillation tower is in the range of 110–120℃, the bottom temperature is 145–155℃, and the reaction time is 0.16–3 h. Subsequently, the washing agent recovered from the top of washing liquid tower 29 is recycled into the washing liquid tank. The heavy components in the bottom of washing liquid tower 29 are cooled and then conveyed to heavy component tank 25. After being washed with detergent, the solid phases of the primary and secondary washers 26 and 27 contain detergent and a small amount of chlorosilane. They are then discharged to centrifuge 31 for centrifugal separation. The liquid chlorosilane separated by centrifuge 31 is transported to chlorosilane tower 28. The solid phase is mainly silicon copper powder, which is unloaded by the centrifuge, bagged and stored, and the exhaust gas is sent to the exhaust gas system for treatment.

[0120] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for recycling chlorosilane slurry, comprising the following steps: Step 1: solid-liquid separation of chlorosilane slurry to obtain crude chlorosilane liquid; Step 2: reaction of the crude chlorosilane with ethanol to obtain crude silicate; Step 3: purification of the crude silicate to obtain silicate product; The solid-liquid separation of the chlorosilane slurry in step 1 to obtain the crude chlorosilane liquid specifically comprises the following steps: S1.1: cooling and pressure reduction treatment of the chlorosilane slurry, so that the temperature of the chlorosilane slurry is controlled at 50-60℃, to obtain chlorosilane flash steam and chlorosilane solid-liquid mixture; S1.2: solid-liquid separation of the chlorosilane solid-liquid mixture to obtain crude chlorosilane liquid and solid residue; S1.3: condensation of the chlorosilane flash steam to obtain chlorosilane condensate; The reaction of the crude chlorosilane with ethanol in step 2 to obtain crude silicate is carried out in a reaction tower, and the gas phase in the reaction tower is collected by an absorption tower, and the chloroethane in the gas phase is absorbed by the chlorosilane liquid, and the liquid in the tower of the absorption tower is introduced into a regeneration tower A, and the hydrogen chloride impurities are removed by distillation, and the liquid in the tower of the regeneration tower A is discharged to a regeneration tower B, and the chloroethane separated from the regeneration tower B is reacted with sodium hydroxide solution to generate ethanol.

2. The method for recycling of chlorosilane sludge liquid according to claim 1, characterized in that, In step S1.1, the temperature range of the cooling and pressure reduction treatment of the chlorosilane slurry is from 145-155℃ to 50-60℃, the pressure range is from 1.4-1.6MPa to 0.01-0.7MPa, and the treatment time is 0.33-2h.

3. The method of recycling chlorosilane slurry according to claim 1, wherein In step S1.2, it further comprises step S1.2.1: washing the solid residue and recovering the washing liquid containing chlorosilane obtained by washing; and the washing agent used in step S1.2.1 is toluene.

4. The method of recycling chlorosilane slurry according to claim 1, wherein In step S1.3, the condensation temperature is 20-25℃, and the condensation time is 0.002-0.5h.

5. The method of recycling chlorosilane slurry according to claim 3, wherein The reaction of chlorosilane with ethanol in step 2 to obtain crude silicate specifically comprises the following steps: S2.1: distillation treatment of the crude chlorosilane liquid obtained in step S1.2, the washing liquid containing chlorosilane recovered in step S1.2.1, and the chlorosilane condensate obtained in step S1.3 to obtain purified chlorosilane; S2.2: reaction of the purified chlorosilane with ethanol to prepare crude silicate.

6. The method of recycling chlorosilane slurry according to claim 5, wherein In step S2.1, the distillation tower bottom temperature range is 160-165℃, the tower top temperature range is 69-75℃, the distillation pressure is 0.05-0.07MPa, and the distillation time is 1-3h.

7. The method of recycling chlorosilane slurry according to claim 5, wherein In step S2.2, the purified chlorosilane and ethanol are reacted in a reaction tower, wherein the mass ratio of the purified chlorosilane to ethanol is 0.72-0.76:1, the reaction tower top temperature range is 33-37℃, the tower bottom temperature is 100-105℃, the reaction tower top pressure is 57-63KPa, the reaction tower bottom liquid level accounts for 45-55% of the volume of the reaction tower bottom, and the ethanol used in the reaction is anhydrous ethanol.

8. The method of recycling chlorosilane slurry according to claim 1, wherein Step 3: purification of the crude silicate to obtain silicate product, specifically comprising the following steps: S3.1: removing the acidic impurities of the crude silicate by the method of deacidification under negative pressure, and obtaining a silicate; S3.2: obtaining a silicate product by decolorizing the silicate treated in S3.

1.

9. The method of recycling chlorosilane slurry according to claim 8, wherein In step S3.1, the negative pressure range used is -90~-60KPa, and the reaction time is 0.16~0.5h.

10. The method of recycling a chlorosilane sludge solution according to claim 9, wherein In step S3.2, the filter is used to decolorize the silicate.

11. An apparatus for recycling chlorosilane slurry, for use in the method of any one of claims 1-10, characterized in that, The preliminary recovery device and the silicate production device are included. The preliminary recovery device includes a separator (3), a mixing kettle (1), a flash vapor condenser (2), and a crude chlorosilane tank (5), The separator (3) is used for solid-liquid separation of chlorosilane slurry liquid, and the crude chlorosilane liquid is recovered. The mixing kettle (1) is provided with a stirrer and a cooling jacket, and is used for cooling and pressure reduction of the chlorosilane slurry liquid to obtain chlorosilane flash vapor and chlorosilane solid-liquid mixture at the bottom of the kettle, and the chlorosilane solid-liquid mixture is transported to the separator (3) at the bottom of the mixing kettle (1). The flash vapor condenser (2) is used to condense the chlorosilane flash vapor output from the mixing kettle (1) to obtain chlorosilane condensate. The crude chlorosilane tank (5) is used to collect the chlorosilane condensate output from the flash vapor condenser (2) and the crude chlorosilane liquid separated from the separator (3), and the chlorosilane liquid collected in the crude chlorosilane tank (5) is transported to the distillation column for rectification and purification, and the chlorosilane gas recovered from the top of the distillation column is transported to the silicate production device. The silicate production device includes a reaction column (7), a deacidification column (8) and a filter (9), an absorption column (19), a regeneration column A (20), a regeneration column B (21), and a first hydrolysis reaction kettle (22): The reaction column (7) is used for the reaction of the chlorosilane gas after rectification and purification in the distillation column of the preliminary recovery device with ethanol to generate crude silicate. The deacidification column (8) is used to remove acidic substances from the crude silicate generated by the reaction in the reaction column (7). The filter (9) is used to decolorize the crude silicate after removing the acidic substances. The absorption column (19) is used to collect the gas phase discharged from the reaction column (7) and to absorb chloroethane in the gas phase, and the chlorosilane liquid in the absorption column (19) absorbs chloroethane as column kettle liquid into the regeneration column A (20). The regeneration column A is used to remove hydrogen chloride impurities in the chlorosilane liquid, and the column kettle liquid of the regeneration column A is discharged into the regeneration column B (21). The regeneration column B is used to remove chloroethane from the chlorosilane liquid, and the chloroethane is recovered from the top of the regeneration column B and then enters the first hydrolysis reaction kettle (22). The first hydrolysis reaction kettle is used to introduce sodium hydroxide solution and chloroethane for hydrolysis reaction to generate ethanol.

12. The apparatus for recycling chlorosilane sludge solution of claim 11, wherein, The silicate production device further includes a second hydrolysis reaction kettle (12) connected after the filter (9) for producing different specifications of silicate products.

13. The apparatus for recycling chlorosilane slurry according to any one of claims 11-12, wherein, The washing device includes a washer (26), a chlorosilane column (28), and a centrifugal machine (31). The washing device (26) is connected with the solid residue liquid discharge port of the separator (3) and is used for washing the chlorosilane adhered to the solid residue; The centrifuge (31) is used for solid-liquid separation of the chlorosilane solid residue slurry washed by the washing device (26); The chlorosilane column (28) is used for collecting the chlorosilane liquid washed by the washing device (26) and the chlorosilane liquid separated by the centrifuge (31) during the solid-liquid separation, and separating the chlorosilane liquid, and recycling the chlorosilane separated from the top of the chlorosilane column (28) to the reaction column (7) for synthesizing silicate.

14. The apparatus for recycling chlorosilane sludge solution of claim 13, wherein, The washing device further comprises a washing liquid column (29) and a washing liquid tank (30), The washing liquid column (29) is used for separating the washing liquid and the heavy component discharged from the bottom of the chlorosilane column (28); The washing liquid tank (30) is used for collecting the washing liquid separated in the washing liquid column (29).

15. The apparatus for recycling chlorosilane slurry according to any one of claims 11-12, wherein, The silicate production device further comprises a gas-liquid separator (23) and a hydrogen chloride buffer tank (24); The gas-liquid separator (23) is used for collecting the hydrogen chloride in the gas discharged from the top of the absorption column (19) and delivering the hydrogen chloride to the hydrogen chloride buffer tank (24) for use of the polysilicon production system.

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