Method for cleaning heat insulation part of polycrystalline silicon reduction furnace

Abstract

The invention provides a method for cleaning a heat insulation part of a polycrystalline silicon reduction furnace, and relates to the technical field of polycrystalline silicon production equipment. The polycrystalline silicon reduction furnace heat insulation piece cleaning method comprises the following steps that S10, after a polycrystalline silicon reduction furnace is used, a plurality of ceramic ring heat insulation pieces with polycrystalline silicon deposited on the surfaces are detached and placed on a lifting hook placing frame in a sand blasting treatment device; s20, a sand blasting treatment device is started to conduct sand blasting treatment on the surface of the ceramic ring heat insulation part; wherein the sand blasting speed of the sand blasting treatment device is 75-85 m / s; and the single-time sand blasting time of the sand blasting treatment device is 30-50 min. The cleaning speed and efficiency of the heat insulation part can be improved, polycrystalline silicon residues are reduced, and the surface quality of the cleaned heat insulation part is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polycrystalline silicon production equipment, in particular to a polycrystalline silicon reduction furnace heat insulation part cleaning method. BACKGROUND

[0002] Since the Siemens company invented the method of using purified trichlorosilane (SiHCl3) and hydrogen (H2) to react and deposit polycrystalline silicon on the surface of a heated silicon core in the 1950s, the Siemens method, most polycrystalline silicon production has used this method to prepare polycrystalline silicon. The main process flow of the reduction process is: after purification, TCS is vaporized by steam heating and mixed with H2, and then enters the bell jar reactor to perform CVD reaction. During the reaction, the silicon core acts as a reaction carrier, and the electric current heating serves as the heat source for the reaction.

[0003] With the increase of the temperature in the reduction furnace, CVD reaction not only occurs on the surface of the silicon core, but also can occur on any other solid surface with a higher temperature, such as the electrode. If polycrystalline silicon is deposited on the electrode, it is easy to cause tip discharge, which causes the arc to be struck, and affects the product quality, so an insulating ring needs to be added outside the electrode for protection. With the running time of the reduction, polycrystalline silicon is deposited on the insulating ring and the insulating cover. Therefore, in the prior art, after the silicon rod is taken out of the furnace, the heat insulation part needs to be soaked in high-temperature lye to remove the deposited polycrystalline silicon, and then rinsed and dried before being reloaded into the furnace for use. However, the existing high-temperature lye soaking treatment process is complex, and the treatment time is long, which can seriously reduce the efficiency of polycrystalline silicon production. SUMMARY

[0004] The present application provides a polycrystalline silicon reduction furnace heat insulation part cleaning method which can improve the speed and efficiency of cleaning the heat insulation part, reduce the residual polycrystalline silicon, and improve the surface quality of the cleaned heat insulation part, to solve the problem of the complex process flow and long treatment time of the high-temperature lye soaking treatment method in the prior art, which can seriously reduce the efficiency of polycrystalline silicon production.

[0005] The technical scheme adopted by the present application is as follows:

[0006] A polycrystalline silicon reduction furnace heat insulation part cleaning method, comprising the following steps:

[0007] S10. After the polycrystalline silicon reduction furnace is used, a plurality of ceramic ring heat insulation parts with polycrystalline silicon deposited on the surface are removed and placed on a hook placement rack in a sandblasting treatment device;

[0008] S20. Start the sandblasting treatment device to perform sandblasting treatment on the surface of the ceramic ring heat insulation part;

[0009] The sandblasting speed of the sandblasting treatment device is 75-85 m / s, and the single sandblasting time of the sandblasting treatment device is 30-50 min.

[0010] Further, the number of ceramic ring heat insulation pieces placed on the hook placement rack of the sand blasting device at a time is 100-320.

[0011] Further, the number of ceramic ring heat insulation pieces placed on the hook placement rack of the sand blasting device at a time is 200-320.

[0012] Further, the ceramic ring heat insulation piece comprises a silicon nitride ceramic ring heat insulation piece.

[0013] Further, the sand blasting device is a hook type shot blasting machine; the hook type shot blasting machine has at least a shot blasting cleaning chamber; the shot blasting cleaning chamber is internally provided with a hook rotation system, and the shot blasting cleaning chamber is further provided with a shot blasting machine assembly and a pneumatic shot supply system; the shot blasting cleaning chamber is externally provided with an electric control system; the electric control system is electrically connected with the shot blasting machine assembly and the pneumatic shot supply system.

[0014] Further, the wear-resistant guard plate in the shot blasting cleaning chamber adopts a Mn13 steel plate; the vulnerable position in the shot blasting cleaning chamber adopts a quenched Cr12MoV steel plate and a Mn13 steel plate for double protection.

[0015] Further, the shot blasting cleaning chamber is provided with a pneumatic door, and the pneumatic door is provided with multiple labyrinth structures for sealing.

[0016] Further, the sand blasting abrasive used by the sand blasting device comprises high-pressure silicon carbide.

[0017] Further, the sand blasting speed of the sand blasting device is 75-80 m / s.

[0018] Further, the single sand blasting time of the sand blasting device is 30-40 min.

[0019] The beneficial effects of the present application are:

[0020] 1. The present application places the ceramic ring heat insulation piece used after the polycrystalline silicon reduction furnace in the hook placement rack of the sand blasting device, uniformly distributes it, and then removes the deposited polycrystalline silicon material on the surface of the ceramic ring heat insulation piece through sand blasting treatment, and relies on the control of the abrasive blasting speed and blasting treatment time to avoid damage to the surface of the ceramic ring heat insulation piece and excessive temperature in the sand blasting device, realizes efficient and fast surface cleaning of the ceramic ring heat insulation piece used after the polycrystalline silicon reduction furnace, and reduces the energy consumption, material consumption and silicon residue of the traditional high-temperature lye soaking method, solves the problem of complex process flow, long processing time and serious reduction of polycrystalline silicon production efficiency in the prior art high-temperature lye soaking treatment method. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required by the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0022] Figure 1 Flow chart of the cleaning method of the embodiment of the present application. DETAILED DESCRIPTION

[0023] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0024] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0025] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0026] In the existing general Siemens method for producing polysilicon, after the reduction of silicon rods is completed, the heat insulation part needs to be soaked in high-temperature alkali solution to remove the deposited polysilicon, and then rinsed, dried and reloaded into the furnace for use. However, the high-temperature alkali soaking treatment process is complex, the treatment time is long, and the efficiency of polysilicon production is seriously reduced.

[0027] In order to solve the above problems in the prior art, the present embodiment provides a polysilicon reduction furnace heat insulation part cleaning method for cleaning the heat insulation part with deposited polysilicon on the surface after the reduction of silicon rods is completed. The polysilicon reduction furnace heat insulation part cleaning method can improve the speed and efficiency of heat insulation part cleaning, reduce polysilicon residue and improve the surface quality of the cleaned heat insulation part. Please refer to Figure 1 The polysilicon reduction furnace heat insulation part cleaning method uses a sandblasting treatment device to clean the surface of the silicon nitride ceramic ring heat insulation part.

[0028] The sand blasting device used in the embodiment is internally provided with a plurality of layers of multi-directional hook placement racks.

[0029] The polycrystalline silicon reduction furnace insulation member cleaning method of the embodiment mainly comprises the following steps:

[0030] S10. After the polycrystalline silicon reduction furnace is used, a plurality of silicon nitride ceramic ring insulation members with polycrystalline silicon deposited on the surface are removed and placed on the hook placement racks in the sand blasting device and evenly distributed.

[0031] S20. The sand blasting device is started to perform sand blasting treatment on the surface of the silicon nitride ceramic ring insulation member; thereby removing the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring insulation member, facilitating the performance stability in the next use.

[0032] The sand blasting device of the embodiment adopts a hook-type shot blasting machine, which mainly comprises a shot blasting cleaning chamber, a hook self-rotation system, a shot blasting machine assembly, a gas-controlled shot supply system, an electric control system, etc. The hook placement racks are part of the hook self-rotation system and are arranged inside the shot blasting cleaning chamber. The shot blasting machine assembly and the gas-controlled shot supply system are arranged outside the shot blasting cleaning chamber and are in communication with the inside of the shot blasting cleaning chamber. The electric control system is arranged outside the shot blasting cleaning chamber, and the electric control system is electrically connected with the shot blasting machine assembly and the gas-controlled shot supply system. Before sand blasting treatment, the shot blasting cleaning chamber is opened to facilitate the operator to place the silicon nitride ceramic ring insulation member on the hook placement racks. During the sand blasting process, the shot blasting cleaning chamber is closed, and the sand blasting treatment is performed in a closed space. The opening and closing of the shot blasting cleaning chamber is controlled by a manually operated double-door, and the manually operated double-door also links the sealing of the top of the shot blasting cleaning chamber. In order to keep the steel shots of the hook-type shot blasting machine uniformly sprayed onto the surface of the insulation member, thereby peeling off the polycrystalline silicon deposited on the surface of the insulation member, the process parameters of the hook-type shot blasting machine need to be controlled. The shot blasting speed is controlled at 75-85 m / s by adjusting the shot blasting machine assembly and the gas-controlled shot supply system through the electric control system. If the speed is too low, the sand blasting treatment will not be complete, and the residual silicon material will increase. If the speed is too high, the silicon nitride ceramic ring insulation member will be easily damaged. Moreover, the single sand blasting time of the sand blasting device is controlled at 30-50 min by adjusting the shot blasting machine assembly and the gas-controlled shot supply system through the electric control system. If the sand blasting time is too short, the sand blasting treatment will not be complete, and the residual silicon material will increase. If the sand blasting time is too long, the temperature inside the shot blasting cleaning chamber will be too high, which will accelerate the wear of the inner wall material and the steel shots in the shot blasting cleaning chamber.

[0033] In the present embodiment, the polysilicon reduction furnace insulation cleaning method places the ceramic ring insulation after the polysilicon reduction furnace is used on the hook placement rack in the sandblasting treatment device, uniformly distributes, and then removes the deposited polysilicon silicon material on the surface of the ceramic ring insulation by sandblasting treatment. The abrasive blasting speed and blasting treatment time of the sandblasting treatment are controlled to avoid damage to the surface of the ceramic ring insulation and excessive temperature in the sandblasting treatment device, realize efficient and fast surface cleaning of the ceramic ring insulation after the polysilicon reduction furnace is used, and reduce the energy consumption, material consumption, and silicon residue of the traditional high-temperature alkali immersion method. The process flow of the high-temperature alkali immersion treatment method in the prior art is complex, the processing time is long, and the efficiency of polysilicon production is seriously reduced.

[0034] At the same time, in the present embodiment, the surface quality of the ceramic ring insulation is improved by sandblasting treatment, the wear resistance and flatness of the surface are improved, and repeated installation and use in a high-temperature environment are facilitated.

[0035] Further, the number of silicon nitride ceramic rings placed on the hook placement rack of the hook-type shot blasting machine in the present embodiment is 100-320 each time. Too many silicon nitride ceramic rings placed at a time will lead to incomplete sandblasting treatment and increased residual silicon. Too few silicon nitride ceramic rings placed at a time will easily lead to excessive impact on the inside of the shot blasting cleaning chamber, increasing the loss of the inner wall material and steel shots.

[0036] Further, in the hook-type shot blasting machine of the present embodiment, to meet the needs of processing multiple silicon nitride ceramic rings, the volume of the shot blasting cleaning chamber is increased, the size is increased from 1800x1800x2800 (mm) of the standard equipment chamber body, the effective cleaning range is increased from ∮1000x1200 (mm) to 2200x2200x3800 (mm), the effective cleaning range is increased from ∮1600x2000 (mm), and four 18.5-kilowatt high-efficiency reinforced shot blasters are arranged in the shot blaster assembly. In addition, the hook-type shot blasting machine of the present embodiment is also provided with a rolling screen for separation, which is suitable for products with more dust residues, can screen the silicon slag, dust, and abrasive generated during workpiece cleaning, the effect reaches more than 95%, and a magnetic separation device is added. The hook-type shot blasting machine of the present embodiment is also provided with a dust removal system. The dust removal system uses an environmentally friendly cloth bag explosion-proof dust removal device, which is more suitable for products with more dust residues and has a longer service life. In addition, to cope with the environment with more silicon powder, the electrical system uses an explosion-proof electrical control.

[0037] Further, the bottom of the hook-type shot blasting machine of the present embodiment is also provided with an elevator. The lower roller of the elevator adopts a squirrel-cage structure, and the lifting belt adopts a rubber belt, which has a significantly improved service life.

[0038] Further, the wear-resistant protective plate in the shot blasting chamber body of the present embodiment is made of Mn13 wear-resistant steel plate, which has high wear resistance and high impact resistance. Quenching Cr12MoV steel plate and Mn13 wear-resistant steel plate are used for double protection at local vulnerable positions to prevent damage caused by failure to timely maintain the equipment.

[0039] In one or more other embodiments, the shot blasting chamber of the hook-type shot blasting machine can also use a pneumatic door, which is easy to open and can reduce the labor intensity of workers. The pneumatic door can also be sealed by multiple labyrinths, effectively preventing steel shot from splashing and injuring people, while saving costs caused by steel shot leakage.

[0040] In one or more other embodiments, the hook-type shot blasting machine can also use high-pressure silicon carbide blasting as an abrasive. Silicon carbide is one of the most superior abrasives recognized, which can be used not only as an abrasive but also as a grinding tool. The reasons for choosing silicon carbide are as follows: 1. Silicon carbide is a material known for its high hardness and strong wear resistance. In the sandblasting operation, silicon carbide particles can effectively remove rust, coatings and dirt on the metal surface, thereby improving the cleaning effect. The improvement of rust removal efficiency helps to improve work efficiency and reduce costs; 2. Silicon carbide has strong chemical corrosion resistance. The crystal structure of silicon carbide contains silicon atoms and carbon atoms, which form very strong covalent bonds between them. This strong chemical bond makes the molecular structure of silicon carbide highly stable and less likely to react chemically. 3. Silicon carbide blasting is a mechanical surface treatment method, whose working principle is to use high-speed ejected silicon carbide particles to hit the surface of the workpiece to remove the protruding parts on the surface, achieving a smooth and smooth effect. Therefore, by using silicon carbide blasting, on the one hand, the protruding parts on the surface of the workpiece can be effectively removed, making the surface more flat and smooth; on the other hand, the surface quality of the workpiece can be improved, enhancing its hardness and wear resistance, and prolonging its service life during use; at the same time, silicon carbide blasting can also remove oxides and grease and other dirt on the surface of the workpiece, avoiding the influence of the presence of dirt on the normal work in the reduction furnace.

[0041] Preferably, in the present embodiment, the blasting speed of the hook-type shot blasting machine is controlled at 75-80 m / s; the single blasting time of the hook-type shot blasting machine is controlled at 30-40 min; and the number of silicon nitride ceramic ring heat insulators placed on the hook placement rack of the hook-type shot blasting machine at a time is 200-320, which can effectively control the residual amount of polysilicon on the surface of the silicon nitride ceramic ring heat insulator, the degree of damage to the surface of the heat insulator, and the internal temperature of the shot blasting chamber during cleaning, and keep them within a range that has less impact on the workpiece and equipment.

[0042] Example 1

[0043] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulating member with polycrystalline silicon deposited on the surface is removed, and after 100 pieces are accumulated, they are placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0044] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and the surface of the silicon nitride ceramic ring heat insulating member is sandblasted using silicon carbide as the abrasive; thereby removing the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulating member. During the sandblasting process, the sandblasting speed of the hook shot blasting machine is controlled at 75 m / s; and the single sandblasting time of the hook shot blasting machine is 30 min.

[0045] After the treatment is completed, the shot blasting cleaning chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating members are taken out for detection.

[0046] Example 2

[0047] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulating member with polycrystalline silicon deposited on the surface is removed, and after 200 pieces are accumulated, they are placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0048] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and the surface of the silicon nitride ceramic ring heat insulating member is sandblasted using silicon carbide as the abrasive; thereby removing the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulating member. During the sandblasting process, the sandblasting speed of the hook shot blasting machine is controlled at 80 m / s; and the single sandblasting time of the hook shot blasting machine is 30 min.

[0049] After the treatment is completed, the shot blasting cleaning chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating members are taken out for detection.

[0050] Example 3

[0051] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulating member with polycrystalline silicon deposited on the surface is removed, and after 320 pieces are accumulated, they are placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0052] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and the surface of the silicon nitride ceramic ring heat insulating member is sandblasted using silicon carbide as the abrasive; thereby removing the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulating member. During the sandblasting process, the sandblasting speed of the hook shot blasting machine is controlled at 85 m / s; and the single sandblasting time of the hook shot blasting machine is 30 min.

[0053] After the treatment is completed, the shot blasting cleaning chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating members are taken out for detection.

[0054] Example 4

[0055] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulator with polycrystalline silicon deposited on the surface is disassembled, accumulated to 320, and placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0056] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and silicon carbide is used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulator; so as to remove the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulator. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine is controlled at 75 m / s; the single sand blasting time of the hook shot blasting machine is 40 min.

[0057] After the treatment is completed, the shot blasting cleaning chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulators are taken out for detection.

[0058] Example 5

[0059] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulator with polycrystalline silicon deposited on the surface is disassembled, accumulated to 320, and placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0060] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and silicon carbide is used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulator; so as to remove the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulator. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine is controlled at 82 m / s; the single sand blasting time of the hook shot blasting machine is 40 min.

[0061] After the treatment is completed, the shot blasting cleaning chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulators are taken out for detection.

[0062] Example 6

[0063] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulator with polycrystalline silicon deposited on the surface is disassembled, accumulated to 320, and placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0064] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and silicon carbide is used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulator; so as to remove the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulator. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine is controlled at 85 m / s; the single sand blasting time of the hook shot blasting machine is 40 min.

[0065] After the treatment, open the shot blasting cleaning chamber of the hook shot blasting machine, and take out all the treated silicon nitride ceramic ring heat insulation pieces for detection.

[0066] Example 7

[0067] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulation pieces with polycrystalline silicon deposited on the surface are disassembled, and after 200 pieces are accumulated, they are placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0068] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, and the hook shot blasting machine is started. Silicon carbide is used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulation piece; so as to remove the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulation piece. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine is controlled at 76 m / s; and the single sand blasting time of the hook shot blasting machine is 50 min.

[0069] After the treatment, open the shot blasting cleaning chamber of the hook shot blasting machine, and take out all the treated silicon nitride ceramic ring heat insulation pieces for detection.

[0070] Example 8

[0071] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulation pieces with polycrystalline silicon deposited on the surface are disassembled, and after 200 pieces are accumulated, they are placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0072] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, and the hook shot blasting machine is started. Silicon carbide is used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulation piece; so as to remove the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulation piece. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine is controlled at 76 m / s; and the single sand blasting time of the hook shot blasting machine is 50 min.

[0073] After the treatment, open the shot blasting cleaning chamber of the hook shot blasting machine, and take out all the treated silicon nitride ceramic ring heat insulation pieces for detection.

[0074] Example 9

[0075] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulation pieces with polycrystalline silicon deposited on the surface are disassembled, and after 200 pieces are accumulated, they are placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0076] Then, the shot blasting chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and the surface of the silicon nitride ceramic ring heat insulating member is sandblasted using silicon carbide as the abrasive; so as to remove the polysilicon deposited on the surface of the silicon nitride ceramic ring heat insulating member. During the sandblasting process, the sandblasting speed of the hook shot blasting machine is controlled at 84 m / s; and the single sandblasting time of the hook shot blasting machine is 50 min.

[0077] After the treatment is completed, the shot blasting chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating members are taken out for detection.

[0078] Example 10

[0079] After the polysilicon reduction furnace is used, the silicon nitride ceramic ring heat insulating member with polysilicon deposited on the surface is disassembled, and after 220 are accumulated, they are placed on the hook placement rack in the shot blasting chamber of the hook shot blasting machine and evenly distributed.

[0080] Then, the shot blasting chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and the surface of the silicon nitride ceramic ring heat insulating member is sandblasted using silicon carbide as the abrasive; so as to remove the polysilicon deposited on the surface of the silicon nitride ceramic ring heat insulating member. During the sandblasting process, the sandblasting speed of the hook shot blasting machine is controlled at 84 m / s; and the single sandblasting time of the hook shot blasting machine is 50 min.

[0081] After the treatment is completed, the shot blasting chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating members are taken out for detection.

[0082] Example 11

[0083] After the polysilicon reduction furnace is used, the silicon nitride ceramic ring heat insulating member with polysilicon deposited on the surface is disassembled, and after 240 are accumulated, they are placed on the hook placement rack in the shot blasting chamber of the hook shot blasting machine and evenly distributed.

[0084] Then, the shot blasting chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and the surface of the silicon nitride ceramic ring heat insulating member is sandblasted using silicon carbide as the abrasive; so as to remove the polysilicon deposited on the surface of the silicon nitride ceramic ring heat insulating member. During the sandblasting process, the sandblasting speed of the hook shot blasting machine is controlled at 84 m / s; and the single sandblasting time of the hook shot blasting machine is 50 min.

[0085] After the treatment is completed, the shot blasting chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating members are taken out for detection.

[0086] Example 12

[0087] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulating member with polycrystalline silicon deposited on the surface is disassembled, and after 260 accumulations, is placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0088] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and silicon carbide is used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulating member; so as to remove the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulating member. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine is controlled at 80 m / s; and the single sand blasting time of the hook shot blasting machine is 40 min.

[0089] After the treatment is completed, the shot blasting cleaning chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating members are taken out for detection.

[0090] Comparative Example 1

[0091] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulating member with polycrystalline silicon deposited on the surface is disassembled, and after 100 accumulations, is placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0092] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and silicon carbide is used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulating member; so as to remove the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulating member. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine is controlled at 70 m / s; and the single sand blasting time of the hook shot blasting machine is 40 min.

[0093] After the treatment is completed, the shot blasting cleaning chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating members are taken out for detection.

[0094] Comparative Example 2

[0095] After the use of the polycrystalline silicon reduction furnace, the silicon nitride ceramic ring heat insulating member with polycrystalline silicon deposited on the surface is disassembled, and after 100 accumulations, is placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0096] Then, the shot blasting cleaning chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and silicon carbide is used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulating member; so as to remove the polycrystalline silicon deposited on the surface of the silicon nitride ceramic ring heat insulating member. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine is controlled at 90 m / s; and the single sand blasting time of the hook shot blasting machine is 40 min.

[0097] After the treatment is completed, the shot blasting cleaning chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating members are taken out for detection.

[0098] Comparative Example 3

[0099] After the use of the polysilicon reduction furnace, the silicon nitride ceramic ring heat insulator with polysilicon deposited on the surface was removed, and after 100 were accumulated, they were placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0100] Then, the shot blasting cleaning chamber of the hook shot blasting machine was closed, the hook shot blasting machine was started, and silicon carbide was used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulator; thereby removing the polysilicon deposited on the surface of the silicon nitride ceramic ring heat insulator. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine was controlled at 100 m / s; the single sand blasting time of the hook shot blasting machine was 40 min.

[0101] After the treatment was completed, the shot blasting cleaning chamber of the hook shot blasting machine was opened, and all the treated silicon nitride ceramic ring heat insulators were taken out for detection.

[0102] Comparative Example 4

[0103] After the use of the polysilicon reduction furnace, the silicon nitride ceramic ring heat insulator with polysilicon deposited on the surface was removed, and after 150 were accumulated, they were placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0104] Then, the shot blasting cleaning chamber of the hook shot blasting machine was closed, the hook shot blasting machine was started, and silicon carbide was used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulator; thereby removing the polysilicon deposited on the surface of the silicon nitride ceramic ring heat insulator. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine was controlled at 82 m / s; the single sand blasting time of the hook shot blasting machine was 20 min.

[0105] After the treatment was completed, the shot blasting cleaning chamber of the hook shot blasting machine was opened, and all the treated silicon nitride ceramic ring heat insulators were taken out for detection.

[0106] Comparative Example 5

[0107] After the use of the polysilicon reduction furnace, the silicon nitride ceramic ring heat insulator with polysilicon deposited on the surface was removed, and after 150 were accumulated, they were placed on the hook placement rack in the shot blasting cleaning chamber of the hook shot blasting machine and evenly distributed.

[0108] Then, the shot blasting cleaning chamber of the hook shot blasting machine was closed, the hook shot blasting machine was started, and silicon carbide was used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulator; thereby removing the polysilicon deposited on the surface of the silicon nitride ceramic ring heat insulator. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine was controlled at 77 m / s; the single sand blasting time of the hook shot blasting machine was 60 min.

[0109] After the treatment, open the shot blasting chamber of the hook shot blasting machine, and take out all the treated silicon nitride ceramic ring heat insulation pieces for detection.

[0110] Comparative Example 6

[0111] After the use of the polysilicon reduction furnace, the silicon nitride ceramic ring heat insulation pieces with polysilicon deposited on the surface were removed, and after 150 pieces were accumulated, they were placed on the hook placement rack in the shot blasting chamber of the hook shot blasting machine and evenly distributed.

[0112] Then, the shot blasting chamber of the hook shot blasting machine was closed, and the hook shot blasting machine was started. Silicon carbide was used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulation pieces; thereby removing the polysilicon deposited on the surface of the silicon nitride ceramic ring heat insulation pieces. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine was controlled at 85 m / s; and the single sand blasting time of the hook shot blasting machine was 70 min.

[0113] After the treatment, open the shot blasting chamber of the hook shot blasting machine, and take out all the treated silicon nitride ceramic ring heat insulation pieces for detection.

[0114] Comparative Example 7

[0115] After the use of the polysilicon reduction furnace, the silicon nitride ceramic ring heat insulation pieces with polysilicon deposited on the surface were removed, and after 350 pieces were accumulated, they were placed on the hook placement rack in the shot blasting chamber of the hook shot blasting machine and evenly distributed.

[0116] Then, the shot blasting chamber of the hook shot blasting machine was closed, and the hook shot blasting machine was started. Silicon carbide was used as abrasive to perform sand blasting treatment on the surface of the silicon nitride ceramic ring heat insulation pieces; thereby removing the polysilicon deposited on the surface of the silicon nitride ceramic ring heat insulation pieces. During the sand blasting treatment, the sand blasting speed of the hook shot blasting machine was controlled at 82 m / s; and the single sand blasting time of the hook shot blasting machine was 40 min.

[0117] After the treatment, open the shot blasting chamber of the hook shot blasting machine, and take out all the treated silicon nitride ceramic ring heat insulation pieces for detection.

[0118] Comparative Example 8

[0119] After the use of the polysilicon reduction furnace, the silicon nitride ceramic ring heat insulation pieces with polysilicon deposited on the surface were removed, and after 400 pieces were accumulated, they were placed on the hook placement rack in the shot blasting chamber of the hook shot blasting machine and evenly distributed.

[0120] Then, the shot blasting chamber of the hook shot blasting machine is closed, the hook shot blasting machine is started, and the surface of the silicon nitride ceramic ring heat insulating piece is sandblasted using silicon carbide as the abrasive; so as to remove the deposited polysilicon on the surface of the silicon nitride ceramic ring heat insulating piece. During the sandblasting process, the sandblasting speed of the hook shot blasting machine is controlled at 80 m / s; and the single sandblasting time of the hook shot blasting machine is 40 min.

[0121] After the treatment is completed, the shot blasting chamber of the hook shot blasting machine is opened, and all the treated silicon nitride ceramic ring heat insulating pieces are taken out for detection.

[0122] Experimental results

[0123] The silicon nitride ceramic ring heat insulating piece samples before and after the treatment of the above-mentioned embodiments 1-12 and comparative examples 1-9 are detected: the weight of the heat insulating piece before the reduction furnace works m1, the weight of the heat insulating piece after the reduction furnace works M1, the weight of the heat insulating piece after sandblasting M2, and the weight of the heat insulating piece after sandblasting and complete treatment (long time high temperature alkali immersion) m2. And the temperature T1 of the inner side wall of the shot blasting chamber is detected during the sandblasting process.

[0124] Then, the percentage of residual silicon W% and the damage degree of the heat insulating piece w% before and after the treatment are calculated, and the formula is as follows:

[0125]

[0126]

[0127] The calculation results of the obtained experimental data are shown in the following table 1.

[0128] From the table, it can be seen that when the sandblasting speed of the hook shot blasting machine reaches 90 m / s and 100 m / s, the damage degree of the surface of the heat insulating piece is obviously increased from about 0.2% to more than 1%, which is not conducive to the service life of the heat insulating piece; when the sandblasting speed of the hook shot blasting machine is reduced to 70 m / s, the percentage of residual silicon on the surface of the heat insulating piece is obviously increased from below 3% to more than 7%, which is not conducive to the complete cleaning of the heat insulating piece. Therefore, the sandblasting speed of the hook shot blasting machine is controlled at 75-85 m / s, which can meet the needs of the invention.

[0129] When the single sandblasting time of the hook shot blasting machine reaches 60 min and 70 min, the temperature inside the cleaning chamber is obviously increased from about 40-50℃ to more than 70℃, which is not conducive to the service life of the shot blasting chamber; when the single sandblasting time of the hook shot blasting machine is reduced to 20 min, the percentage of residual silicon on the surface of the heat insulating piece is obviously increased from below 3% to more than 10%, which is not conducive to the complete cleaning of the heat insulating piece. Therefore, the single sandblasting time of the hook shot blasting machine is controlled at 30-50 min, which can meet the needs of the invention.

[0130] When the number of the silicon nitride ceramic ring heat insulation pieces placed on the hook placing rack of the hook type shot blasting machine is 350 or 400 each time, the percentage of silicon residue on the surface of the heat insulation piece is obviously increased from less than 3% to more than 6%, which is not conducive to the thorough cleaning of the heat insulation piece. Therefore, the number of the silicon nitride ceramic ring heat insulation pieces placed on the hook placing rack of the hook type shot blasting machine is 100-320 each time, which can meet the needs of the application.

[0131] Further, when the sand blasting speed of the hook type shot blasting machine is controlled at 75-80 m / s, the single sand blasting time of the hook type shot blasting machine is controlled at 30-40 min, and the number of the silicon nitride ceramic ring heat insulation pieces placed on the hook placing rack of the hook type shot blasting machine is 200-320 each time, the residual amount of polycrystalline silicon on the surface of the silicon nitride ceramic ring heat insulation piece, the damage degree of the surface of the heat insulation piece, and the internal temperature of the shot blasting cleaning chamber during cleaning can be effectively controlled comprehensively, and the effect is better.

[0132] The above shows and describes the basic principles, main features and advantages of the application. Those skilled in the art should understand that the application is not limited by the above examples, and the above examples and descriptions in the specification are only preferred examples of the application and are not intended to limit the application. Without departing from the spirit and scope of the application, various changes and improvements can be made to the application, and these changes and improvements all fall within the scope of the claimed application. The scope of protection of the application is defined by the appended claims and their equivalents.

Claims

1. A method of cleaning a polysilicon reduction furnace insulation, comprising: The method comprises the following steps: S10. After use of the polycrystalline silicon reduction furnace, a plurality of ceramic ring heat insulators with polycrystalline silicon deposited on the surface are removed and placed on a hook placement rack in a sand blasting treatment device; S20. The sand blasting treatment device is started to perform sand blasting treatment on the surface of the ceramic ring heat insulator; The sand blasting speed of the sand blasting treatment device is 75-85 m / s; and the single sand blasting time of the sand blasting treatment device is 30-50 min.

2. The polysilicon reduction furnace insulation cleaning method of claim 1, wherein The number of ceramic ring heat insulators placed on the hook placement rack of the sand blasting treatment device at a time is 100-320.

3. The polysilicon reduction furnace insulation cleaning method of claim 2, wherein The number of ceramic ring heat insulators placed on the hook placement rack of the sand blasting treatment device at a time is 200-320.

4. The method of claim 1, wherein The ceramic ring heat insulator comprises a silicon nitride ceramic ring heat insulator.

5. The method of claim 1, wherein The sand blasting treatment device is a hook type shot blasting machine; the hook type shot blasting machine has at least a shot blasting cleaning chamber; the shot blasting cleaning chamber is internally provided with a hook rotation system, and the shot blasting cleaning chamber is further provided with a shot blasting machine assembly and a pneumatic shot supply system on the outside; the shot blasting cleaning chamber is externally provided with an electric control system; the electric control system and the shot blasting machine assembly and the pneumatic shot supply system are electrically connected.

6. The polysilicon reduction furnace insulation cleaning method of claim 5, wherein The wear-resistant guard plate in the shot blasting cleaning chamber is made of Mn13 steel plate; the vulnerable position in the shot blasting cleaning chamber is double-protected by quenching Cr12MoV steel plate and Mn13 steel plate.

7. The polysilicon reduction furnace insulation cleaning method of claim 5, wherein The shot blasting cleaning chamber is provided with a pneumatic door, and the pneumatic door is sealed by a plurality of labyrinth structures.

8. The method of claim 1-7, wherein The sand blasting abrasive used by the sand blasting treatment device comprises high-pressure silicon carbide.

9. The method of claim 1-7, wherein The sand blasting speed of the sand blasting treatment device is 75-80 m / s.

10. The method of claim 1-7, wherein The single sand blasting time of the sand blasting treatment device is 30-40 min.

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