Production process and device for preparing high-purity silica sol from polycrystalline silicon broken powder by-products

Abstract

The invention relates to the technical field of silica sol preparation, and provides a production process and device for preparing high-purity silica sol from polycrystalline silicon broken powder byproducts, and the process comprises the following steps: S1, smelting silicon powder; s2, finely crushing the smelted silicon block; s3, silica sol is prepared, and a device comprises an intermediate frequency furnace used for smelting polycrystalline silicon broken powder by-products; the mold is used for cooling the silicon separated by smelting and preparing a silicon block; the crushing equipment is used for finely crushing the silicon blocks to form silicon powder; the reaction kettle is used for reaction of silicon powder; and the plate-and-frame filter press and the tubular centrifuge are used for separating and concentrating to form the high-purity silica sol. The method has the beneficial effects that the polycrystalline silicon crushed powder by-products are smelted through the intermediate frequency furnace to obtain the high-purity silicon blocks, the high-purity silicon blocks are crushed into the high-purity silicon powder with the granularity required for preparing the silica sol with different particle sizes, the high-purity silicon powder is used for preparing the high-purity silica sol, the production cost is reduced, and large-scale production can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of nano-scale silica sol synthesis, and in particular to a production process and a device for preparing high-purity silica sol from a byproduct of polysilicon crushed powder. Background Art

[0002] Silica sol is a colloidal solution formed by uniform dispersion of amorphous silicon dioxide in water. It is widely used in CMP polishing because of its controllable particle size, moderate hardness, low viscosity, low adhesion, and easy cleaning after polishing. As the main component of CMP polishing liquid, the purity of silica sol determines the quality of CMP polishing liquid. The polishing of semiconductor silicon wafers, fine polishing of silicon carbide substrates, and polishing of conductive layers in semiconductor processes require higher purity. Metal ions such as Na, Fe, Al, Ca, Mg, Cu, and Pb can cause defects on the wafer surface, thereby affecting the performance of semiconductors.

[0003] At present, the main processes for preparing silica sol include silane hydrolysis, elemental silicon hydrolysis and ion exchange. Using organic silane as the silicon source and water and alcohol as solvents, high-purity silica sol with extremely low metal impurity content can be obtained. However, this method has high raw material prices, high safety risks in industrial production, and great difficulty in industrialization. Therefore, industrial production is still basically monopolized by Japan's Fuso. The ion exchange method using water glass as raw material is not suitable for the preparation of high-purity silica sol because the iron and aluminum content in the raw material itself is high and difficult to deal with in subsequent treatment.

[0004] The silicon powder hydrolysis process uses elemental silicon as raw material, and currently mainly uses strong bases such as NaOH and KOH as catalysts to obtain silica sol. The purity of the raw silicon powder determines the purity of the silica sol. At present, the content of metal impurities such as Fe, Al, Ca, and Mg in ordinary industrial silicon powder is relatively high, and the price of directly using high-purity polysilicon is extremely high. Therefore, developing a high-purity silicon powder raw material with low finished product to prepare high-purity silica sol meets market demand and has important market value.

[0005] Polysilicon is an important electronic material, widely used in the semiconductor industry and the photovoltaic industry. According to the purity, it can be divided into electronic grade polysilicon and solar grade polysilicon. At present, the silicon materials produced by polysilicon manufacturers are all rod-shaped polysilicon with a diameter of 300-500mm. In the subsequent application of polysilicon, whether it is polycrystalline ingots or single crystal rods, polysilicon needs to be broken into blocks or smaller particles. In the process of crushing polysilicon, fine powder byproducts with a particle size of less than 3mm will be produced. This part of the powder has a fine particle size, different morphology, and uneven particle size, but the purity is very high. The price is extremely advantageous over genuine polycrystalline silicon. How to make good use of this powder to prepare silica sol with high purity and uniform particle size is of great significance. Summary of the invention

[0006] The present application proposes a production process and device for preparing high-purity silica sol from a byproduct of broken polysilicon powder, which is suitable for the mass production of silica sol. The present application smelts the byproduct of broken polysilicon powder through a medium frequency furnace to obtain high-purity silicon blocks, and crushes the high-purity silicon blocks into high-purity silicon powder of the particle size required for preparing silica sols of different particle sizes, which is used to prepare high-purity silica sol. In the present invention, the added cost of smelting the byproduct of broken polysilicon powder through a medium frequency furnace is relatively low, far lower than the price of genuine polysilicon, and the crushed particle size after smelting is controllable, which is more conducive to the preparation of silica sol with uniform particle size. The conversion rate of the crushed silicon powder after smelting is also greatly improved compared to directly using the byproduct powder.

[0007] To this end, the first aspect of the present application provides a production device for preparing high-purity silica sol from polysilicon crushed powder byproduct, comprising: Medium frequency furnace, used for smelting polysilicon crushed powder byproduct; A mold used to cool the silicon separated by smelting and make silicon blocks; Crushing equipment, used for finely crushing the silicon blocks to form silicon powder; Reactor, used for the reaction of silicon powder; Plate and frame filter press and tubular centrifuge are used to separate and concentrate to form high-purity silica sol.

[0008] By adopting the above technical solution: the above device constitutes a production system, the above production process can be realized, the conversion rate of the product is significantly improved after smelting in a medium frequency furnace, and after smelting and crushing, the particle size of the silicon powder is controllable, and silica sol products with different particle sizes can be prepared by controlling different process parameters, which greatly meets the requirements of different polishing liquids for silica sol particle size, and the process is controllable, the product has good stability and high conversion rate.

[0009] Optionally, the crushing equipment includes a shell, a crushing roller is provided at the upper end thereof, and an integrated fine crushing and screening mechanism is provided therein.

[0010] By adopting the above technical solution: the integrated fine crushing and screening mechanism can pre-crush large silicon blocks first, and then finely crush them to meet the particle size requirements of different products.

[0011] Optionally, the integrated fine crushing and screening mechanism includes a driving mechanism arranged at the lower part of the shell, a crushing knife is connected to the output shaft of the driving mechanism, the crushing knife is located at the lower part of the crushing roller, and also includes a bowl-shaped screening mesh plate arranged on the output shaft.

[0012] By adopting the above technical scheme, the silicon blocks pre-crushed by the crushing rollers are formed into particles, which can be finely crushed under the high-speed rotation of the crushing blades. At the same time, when the bowl-shaped screening mesh plate rotates, the particles are thrown to the side of the bowl-shaped screening mesh plate by centrifugal force, and the powder particles that meet the requirements are screened out. The powder particles that do not meet the requirements can be further crushed by the crushing knife after the bowl-shaped screening mesh plate is turned over until they are screened out.

[0013] Optionally, the reactor includes a main body, a fine mixing mechanism is provided inside the main body, the fine mixing mechanism includes a plurality of swing rods connected to the inner wall of the main body through a torsion shaft, a stirring shaft is provided inside the main body, several L-shaped stirring rods are provided on the stirring shaft, and the lower end of the L-shaped stirring rod is overlapped on the swing rod.

[0014] By adopting the above technical solution: when the stirring shaft rotates, the L-shaped stirring rod can rotate for stirring, and at the same time can trigger the swing rod to swing left and right for more sufficient stirring and mixing, thereby improving the reaction efficiency.

[0015] The second aspect of the present application provides a process for preparing high-purity silica sol by using the above-mentioned polysilicon crushed powder byproduct to prepare high-purity silica sol, comprising the following steps: S1. Smelting of silicon powder: Add the broken polysilicon powder byproduct into the medium frequency furnace, add a set amount of co-solvent, start the medium frequency furnace and heat it to the set temperature to melt the broken polysilicon powder byproduct, and perform smelting for a set time to separate the broken polysilicon powder byproduct from the impurities inside it, and pour the separated silicon into a mold to cool and break it into blocks; S2. Fine crushing of smelted silicon blocks: The silicon blocks smelted in the medium frequency furnace are crushed into silicon powder of a set particle size by crushing equipment for the production of silica sol; S3, preparation of silica sol: add a set amount of high-purity water into the reactor, heat it to a set temperature A, start the stirring of the reactor, add a set amount of catalyst into the reactor, add the silicon powder prepared in the above step S2 into the reactor according to a set proportion, control the reaction temperature B through spraying, shell-and-tube cooler, and reactor interlayer circulation, react for a certain time, and discharge the material for solid-liquid separation and concentration.

[0016] By adopting the above technical solution: the polysilicon crushed powder by-product is smelted through a medium frequency furnace to obtain high-purity silicon blocks, and the high-purity silicon blocks are crushed into high-purity silicon powder of the particle size required for preparing silica sols of different particle sizes, which are used to prepare high-purity silica sols, thereby reducing production costs and enabling large-scale production.

[0017] Optionally, in the step S1, Si in the polysilicon crushed powder by-product is ≥ 99%.

[0018] Optionally, the set smelting temperature of the polysilicon crushed powder by-product is 1650-1750°C, the weight ratio of the solvent to the polysilicon crushed powder by-product is 1:80-100, and the set smelting time of the polysilicon crushed powder by-product is 1-2h.

[0019] Optionally, the material of the crushing equipment in step S2 is tungsten carbide, and the set particle size of the silicon powder crushing is 30-325 mesh.

[0020] Optionally, the silicon powder is crushed into two particle sizes: 30-100 mesh and 200-325 mesh.

[0021] Optionally, the resistivity of the high-purity water used in step S3 is 18.2 MΩ.cm, the catalyst used is of premium grade, the type of catalyst is potassium hydroxide or ammonia water, the temperature A is 40-95°C, the temperature B is 85-100°C, the weight ratio of the silicon powder to the high-purity water is 1:0.8-2.5, and the equipment for solid-liquid separation is a plate and frame filter press and a tubular centrifuge.

[0022] The working principle and beneficial effects of this application are: 1. In the present application, the polysilicon crushed powder by-product is smelted through a medium frequency furnace to obtain high-purity silicon blocks, and the high-purity silicon blocks are crushed into high-purity silicon powder of the particle size required for preparing silica sols of different particle sizes, which is used to prepare high-purity silica sols, thereby reducing production costs and enabling mass production.

[0023] 2. The above-mentioned device of the present application constitutes a production system, which can realize the above-mentioned production process. The conversion rate of the product is significantly improved after smelting in a medium frequency furnace. After smelting and crushing, the particle size of the silicon powder is controllable. Silica sol products with different particle sizes can be prepared by controlling different process parameters, which greatly meets the requirements of different polishing liquids for the particle size of silica sol. The process is controllable, the product has good stability and high conversion rate.

[0024] 3. In the present application, the silicon blocks pre-crushed by the crushing rollers are formed into particles, which can be finely crushed under the high-speed rotation of the crushing blades. At the same time, when the bowl-shaped screening mesh plate rotates, the particles are thrown to the side of the bowl-shaped screening mesh plate by centrifugal force. The powder particles that meet the requirements are screened out, and the powder particles that do not meet the requirements can be further crushed by the crushing knife after the bowl-shaped screening mesh plate is turned over until they are screened out, and the particle size is controllable.

[0025] 4. In the present application, when the stirring shaft rotates, the L-shaped stirring rod can rotate for stirring, and at the same time, the swing rod can be triggered to swing left and right for more thorough stirring and mixing, thereby improving the reaction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0027] Figure 1 This is the overall process flow diagram of this application; Figure 2 This is a TEM image of the silica sol particle size of the product of Example 1; Figure 3 This is a TEM image of the silica sol particle size of the product of Example 2; Figure 4 This is the DLS picture of the silica sol particle size of the product of Example 2; Figure 5 This is a picture of the broken byproduct of polysilicon that has not been smelted; Figure 6 This is a picture of the direct preparation of unreacted silicon powder from silica sol without the by-product of smelting polysilicon crushing; Figure 7 This is a picture of 30-100 mesh high-purity silicon powder obtained by smelting and crushing the by-product of polysilicon crushing; Figure 8 This is an overall structural diagram of the device of an embodiment of the present application; Fig. 9 A schematic diagram of the structure of a crushing device according to an embodiment of the present application; Fig.10 This is a schematic diagram of the structure of the reactor implemented in this application.

[0028] In the figure: 100, medium frequency furnace; 200, mold; 300, crushing equipment; 310, shell; 320, crushing roller; 330, driving mechanism; 340, crushing knife; 350, bowl-shaped screening mesh plate; 400, reactor; 410, body; 420, torsion shaft; 430, swing rod; 440, stirring shaft; 450, L-shaped stirring rod; 460, temperature control layer; 500, plate and frame filter press; 600, tubular centrifuge. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] like Figure 1 and Fig.10 As shown, this embodiment provides a production process for preparing high-purity silica sol from polysilicon crushed powder byproduct, comprising the following steps: S1. Smelting of silicon powder: Add the polycrystalline silicon crushed powder byproduct into the medium frequency furnace 100, add a set amount of solvent, wherein the solvent is boric acid (H3BO3) to reduce the melting point of the polycrystalline silicon crushed powder byproduct, improve fluidity, and facilitate processing, start the medium frequency furnace 100 to heat to the set temperature to melt the polycrystalline silicon crushed powder byproduct, and perform smelting for a set time, separate the polycrystalline silicon crushed powder byproduct from the impurities inside, and pour the separated silicon into the mold 200 to cool and crush into blocks; S2. Fine crushing of smelted silicon blocks: The silicon blocks smelted by the medium frequency furnace 100 are crushed into silicon powder of a set particle size by a crushing device 300 for the production of silica sol; S3, preparation of silica sol: add a set amount of high-purity water into the reactor 400, heat it to the set temperature A, start the stirring of the reactor 400, add a set amount of catalyst into the reactor 400, add the silicon powder prepared in the above step S2 into the reactor 400 according to the set proportion, control the reaction temperature B through spraying, shell and tube cooler, and interlayer circulation of the reactor 400, react for a certain time, and discharge the material for solid-liquid separation and concentration.

[0031] The basic principle of this embodiment is as follows: the polysilicon crushed powder by-product is smelted through the medium frequency furnace 100 to obtain high-purity silicon blocks, and the high-purity silicon blocks are crushed into high-purity silicon powder of the particle size required for preparing silica sols of different particle sizes, which is used to prepare high-purity silica sol, thereby reducing production costs and enabling mass production.

[0032] Wherein, in the step S1, Si in the polysilicon crushed powder by-product is ≥ 99%.

[0033] The set smelting temperature of the polysilicon crushed powder by-product is 1650-1750°C, the weight ratio of the solvent to the polysilicon crushed powder by-product is 1:80-100, and the set smelting time of the polysilicon crushed powder by-product is 1-2h.

[0034] Wherein, in the step S2, the material of the crushing device 300 is tungsten carbide, and the set particle size of the silicon powder crushing is 30-325 meshes.

[0035] The set particle sizes of the silicon powder crushing are 30-100 mesh and 200-325 mesh.

[0036] Among them, the resistivity of the high-purity water used in the step S3 is 18.2 MΩ.cm, the catalyst used is of premium purity, the type of catalyst is potassium hydroxide or ammonia water, the temperature A is 40-95°C, the temperature B is 85-100°C, the weight ratio of the silicon powder to the high-purity water is 1:1.5-2.5, and the equipment for solid-liquid separation is a plate and frame filter press 500 and a tubular centrifuge 600.

[0037] More specifically, two specific implementation methods are exemplified below: Example

[0038] Add the broken polysilicon powder byproduct into the medium frequency furnace 100, add a certain amount of co-solvent, start the medium frequency furnace 100, heat to 1700℃ through induction heating technology to melt the silicon powder, separate the silicon powder from the impurities in it at high temperature, pour the separated silicon into the mold 200, cool it, and break it into blocks. Break the smelted silicon blocks into 200-325 meshes. Add high-purity water to prepare slurry for standby use, and the ratio of silicon powder to high-purity water used is 1:2.

[0039] Add 5000 parts of high-purity water to the reactor 400, heat to 50-60°C, start stirring the reactor 400, add 60 parts of high-grade pure potassium hydroxide to the reactor 400, stir for 10-20 minutes, add the prepared silicon powder slurry to the reactor 400 at a frequency of 30HZ, and the silicon powder added to the reactor 400 is 450 parts in terms of dry silicon powder. Turn on the cooling water and spray device, control the reaction temperature between 90-95°C, react for 5 hours, discharge the material for plate and frame filter pressing, centrifuge, and concentrate to 20% content. The silica sol prepared by this reaction is a potassium-type small-particle silica sol with a product particle size of 6nm and other heavy metals <100ppb. The products of this process can be used for mid-polishing of silicon wafers and chips. Products such as Figure 2 shown. Example

[0040] Add the by-product powder of the broken polysilicon into the medium frequency furnace 100, add a certain amount of co-solvent, start the medium frequency furnace 100, heat to 1700℃ through induction heating technology to melt the silicon powder, separate the silicon powder from the impurities inside at high temperature, pour the separated silicon into the mold 200, cool it, and break it into blocks. Break the smelted silicon blocks into 30-100 meshes, add 20 parts of high-grade pure ammonia water to 180 parts of high-purity water to prepare a dilute ammonia solution A.

[0041] Add 3000 parts of high-purity water and 20 parts of high-grade pure ammonia water to the reactor 400, heat to 90-92°C, start stirring of the reactor 400, add 280 parts of silicon powder, react at a constant temperature of 95±2°C, react for 2 hours, and uniformly add A for 30 hours. After adding ammonia water, continue to react for 10 hours, discharge, filter by plate and frame, centrifuge, and concentrate into 40% high-purity ammonia-type silica sol. The silica sol prepared by this reaction is high-purity ammonia-type silica sol, the product particle size is about 50nm, and the particle size distribution is uniform. The silica sol obtained by this reaction has an alkali metal content of <300ppb and a heavy metal content of <100ppb. The purity can reach the same level as Japan's Fuso, and can be used for fine polishing of semiconductors. Products such as Figure 3 and Figure 4 shown.

[0042] The particle size and shape of the polysilicon crushed powder byproduct are uneven, such as Figure 5 Directly using polysilicon crushed powder as a byproduct to produce silica sol will result in uneven particle size and poor stability between batches, which cannot meet normal market demand. In addition, the product conversion rate is low, and a large amount of unreacted flaky powder will remain after the reaction is completed. Figure 6 The present invention can effectively control the particle size of the required high-purity silicon powder, and the purity of the silicon powder can be further improved through smelting technology. The conversion rate of the silicon powder after smelting is significantly improved, and after smelting and crushing, the particle size of the silicon powder can be controlled, such as Figure 7 , high purity, and silica sol products with different particle sizes can be prepared through different processes, which greatly meets the needs of different polishing liquids for silica sol particle size, and the process is controllable, the product has good stability and high conversion rate.

[0043] like Figure 8-Figure 10 The present application provides a production device for preparing high-purity silica sol from polysilicon crushed powder byproduct, comprising: Medium frequency furnace 100, used to smelt by-product powder from broken polysilicon; The mold 200 is used to cool the silicon separated by smelting and make silicon blocks; Crushing equipment 300, used for finely crushing the silicon blocks to form silicon powder; Reactor 400, used for reaction of silicon powder; The plate and frame filter press 500 and the tubular centrifuge 600 are used to separate and concentrate to form high-purity silica sol.

[0044] The overall principle of the above-mentioned device: the above-mentioned device constitutes a production system, which can realize the above-mentioned production process. The conversion rate of the product is significantly improved after smelting in the medium frequency furnace 100, and the particle size of the silicon powder can be controlled after smelting and crushing. Silica sol products with different particle sizes can be prepared by controlling different process parameters, which greatly meets the requirements of different polishing liquids for the particle size of silica sol, and the process is controllable, the product has good stability and high conversion rate.

[0045] The crushing device 300 includes a shell 310, a crushing roller 320 is provided at the upper end thereof, and a fine crushing and screening integrated mechanism is provided therein. The fine crushing and screening integrated mechanism can pre-crush large silicon blocks and then perform fine crushing to meet the particle size requirements of different products.

[0046] The fine crushing and screening integrated mechanism includes a driving mechanism 330 disposed at the lower part of the housing 310, and a crushing knife 340 is connected to the output shaft of the driving mechanism 330, and the crushing knife 340 is located at the lower part of the crushing roller 320, and also includes a bowl-shaped screening mesh plate 350 disposed on the output shaft. The silicon blocks pre-crushed by the crushing rollers are formed into particles, which can be finely crushed under the high-speed rotation of the crushing knife 340. At the same time, when the bowl-shaped screening mesh plate 350 rotates, the particles are thrown to the side of the bowl-shaped screening mesh plate 350 by centrifugal force, and the powder particles that meet the requirements are screened down, and the powder particles that do not meet the requirements can be further crushed by the crushing knife 340 after the bowl-shaped screening mesh plate 350 is turned over until they are screened out.

[0047] The reactor 400 includes a body 410, wherein a fine mixing mechanism is provided inside the body 410, wherein the fine mixing mechanism includes a plurality of swinging rods 430 connected to the inner wall of the body 410 through a torsion shaft 420, wherein a stirring shaft 440 is provided inside the body 410, wherein a plurality of L-shaped stirring rods 450 are provided on the stirring shaft 440, wherein the lower end of the L-shaped stirring rod 450 is overlapped on the swinging rod 430. When the stirring shaft 440 rotates, the L-shaped stirring rod 450 can rotate for stirring, and at the same time can trigger the swinging rod 430 to swing left and right for more sufficient stirring and mixing, thereby improving the reaction efficiency, wherein a temperature control layer 460 is provided on the outer peripheral side of the body 410, and a heating medium circulates inside.

[0048] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A production device for preparing high-purity silica sol from polysilicon crushed powder byproduct, characterized in that: include: Medium frequency furnace (100), used for smelting polysilicon crushed powder byproduct; A mold (200) is used to cool the silicon separated after smelting and make a silicon block; A crushing device (300) for finely crushing the silicon blocks to form silicon powder; A reaction kettle (400) is used for reacting silicon powder; The plate and frame filter press (500) and the tubular centrifuge (600) are used to separate and concentrate to form high-purity silica sol.

2. The production device for preparing high-purity silica sol from polysilicon crushed powder byproduct according to claim 1, characterized in that: The crushing device (300) comprises a shell (310), wherein a crushing roller (320) is provided at the upper end of the shell (310), and a fine crushing and screening integrated mechanism is provided inside the shell (310).

3. The production device for preparing high-purity silica sol from polysilicon crushed powder byproduct according to claim 2, characterized in that: The fine crushing and screening integrated mechanism comprises a driving mechanism (330) arranged at the bottom of a housing (310), a crushing knife (340) being connected to an output shaft of the driving mechanism (330), the crushing knife (340) being located at the bottom of a crushing pair of rollers (320), and a bowl-shaped screening mesh plate (350) being arranged on the output shaft.

4. The production device for preparing high-purity silica sol from polysilicon crushed powder byproduct according to claim 1, characterized in that: The reaction kettle (400) comprises a body (410), a fine mixing mechanism is provided inside the body (410), the fine mixing mechanism comprises a plurality of swinging rods (430) connected to the inner wall of the body (410) via a torsion shaft (420), a stirring shaft (440) is provided inside the body (410), a plurality of L-shaped stirring rods (450) are provided on the stirring shaft (440), and the lower ends of the L-shaped stirring rods (450) are overlapped on the swinging rods (430).

5. A process for preparing high-purity silica sol using the production device for preparing high-purity silica sol from the byproduct of polysilicon crushed powder according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Smelting of silicon powder: adding the polycrystalline silicon crushed powder byproduct into the medium frequency furnace (100), adding a set amount of solvent, starting the medium frequency furnace (100) and heating it to a set temperature to melt the polycrystalline silicon crushed powder byproduct, and smelting for a set time, separating the polycrystalline silicon crushed powder byproduct from the impurities inside, and pouring the separated silicon into a mold (200) to cool and crush it into silicon blocks; S2. Fine crushing of smelted silicon blocks: crushing the silicon blocks smelted in the medium frequency furnace (100) into silicon powder of a set particle size by using a crushing device (300) for use in the production of silica sol; S3, preparation of silica sol: add a set amount of high-purity water into the reactor (400), heat it to a set temperature A, start stirring the reactor (400), add a set amount of catalyst into the reactor (400), add the silicon powder prepared in the above step S2 into the reactor (400) according to a set proportion, control the reaction temperature B through spraying, shell-and-tube cooler and reactor (400), react for a certain time, and discharge the material for solid-liquid separation and concentration.

6. The production process for preparing high-purity silica sol from polysilicon crushed powder byproduct according to claim 5, characterized in that: In the step S1, Si in the polysilicon crushed powder byproduct is ≥ 99%.

7. The production process for preparing high-purity silica sol from polysilicon crushed powder byproduct according to claim 5, characterized in that: The smelting setting temperature of the polysilicon crushed powder by-product is 1650-1750°C, the weight ratio of the solvent to the polysilicon crushed powder by-product is 1:80-100, and the smelting setting time of the polysilicon crushed powder by-product is 1-2h.

8. The production process for preparing high-purity silica sol from polysilicon crushed powder byproduct according to claim 5, characterized in that: In the step S2, the crushing device (300) is made of tungsten carbide, and the set particle size of the silicon powder crushing is 30-325 meshes.

9. The production process for preparing high-purity silica sol from polysilicon crushed powder byproduct according to claim 8, characterized in that: The set particle sizes of the silicon powder crushing are 30-100 mesh and 200-325 mesh.

10. The process for preparing high-purity silica sol from polysilicon crushed powder byproduct according to claim 5, characterized in that: The resistivity of the high-purity water used in step S3 is 18.2 MΩ.cm, the catalyst used is of premium grade purity, the type of catalyst is potassium hydroxide or ammonia water, the temperature A is 40-95°C, the temperature B is 85-100°C, the weight ratio of the silicon powder to the high-purity water is 1:0.8-2.5, and the equipment for solid-liquid separation is a plate and frame filter press (500) and a tubular centrifuge (600).

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