Diatomite and silicon powder recovery system for polycrystalline silicon slurry treatment
By combining drying, reaction and solid-liquid separation units, the waste of silicon powder and diatomaceous earth in polycrystalline silicon slag slurry treatment is solved, and resource recovery and cost reduction are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2026-04-07
AI Technical Summary
In the current polysilicon production process, the slurry treatment process wastes silicon powder and diatomaceous earth with recycling value, and increases the cost of waste residue treatment.
The system employs a drying unit, a reaction unit, and a solid-liquid separation unit to recover silica powder and diatomaceous earth through neutralization, hydrolysis, and solid-liquid separation. The diatomaceous earth and silica powder are recycled as cement additives, and the filtrate is reused as recycled water.
This effectively avoids resource waste, reduces waste residue treatment costs, and achieves resource recycling.
Smart Images
Figure CN224086695U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of polycrystalline silicon production technology, and in particular to a diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment. Background Technology
[0002] With the rapid development of the electronics and information industry, the market demand for polysilicon is gradually increasing. Currently, the most mature method for producing polysilicon is the modified Siemens process. When producing polysilicon using the modified Siemens process, a large amount of mixed slurry is generated in the cold hydrogenation, distillation, and purification stages. This slurry mainly consists of chlorosilanes, high-boiling-point substances, aluminum trichloride, and a small amount of silicon powder. Direct discharge of this slurry will pollute the environment, so it needs to be properly treated.
[0003] Currently, most domestic enterprises use diatomaceous earth to filter out microsilica impurities in the slurry during the slurry treatment process. Then, the diatomaceous earth and microsilica are transported off-site as waste and entrusted to a third party for waste treatment. This not only wastes the raw materials with recycling value in the waste but also increases the cost of waste treatment. Utility Model Content
[0004] Given that the existing slurry process involves using diatomaceous earth to filter out microsilica impurities in the slurry, and then transporting the diatomaceous earth and microsilica as waste and entrusting a third party to handle the waste, this not only wastes the raw materials with recycling value in the waste but also increases the cost of waste treatment. One of the purposes of this application is to provide a diatomaceous earth and silicon powder recovery system for polycrystalline silicon slurry treatment, which recovers silicon powder and diatomaceous earth through neutralization hydrolysis and solid-liquid separation, thereby avoiding resource waste and reducing slurry treatment costs.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] A diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment includes a drying unit, a reaction unit, a solid-liquid separation unit, and a clean water recovery unit.
[0007] The reaction unit includes a hydrolysis tank and a neutralization reaction vessel connected to the outlet of the hydrolysis tank, and the inlet of the hydrolysis tank is connected to the outlet of the drying unit.
[0008] The solid-liquid separation unit includes a sedimentation tank and a filter press. The sedimentation tank includes a first inlet, a supernatant outlet and a suspension outlet. The filter press includes a second inlet, a filtrate outlet and a filter residue outlet.
[0009] The first feed inlet is connected to the outlet of the neutralization reactor, the supernatant outlet and the filtrate outlet are both connected to the inlet of the water recovery unit, and the suspension outlet is connected to the second feed inlet of the filter press.
[0010] Preferably, the hydrolysis tank is connected to the neutralization reactor, the neutralization reactor is connected to the first feed inlet, the suspension outlet is connected to the second feed inlet via conveying pipelines, and each conveying pipeline is equipped with a circulation pump.
[0011] Preferably, the reaction unit further includes a production water conveying device and an alkali conveying device, wherein the production water conveying device is connected to the inlet of the hydrolysis tank and the alkali conveying device is connected to the inlet of the neutralization reactor.
[0012] Preferably, the outer wall of the hydrolysis tank is provided with a cooling device.
[0013] Preferably, the cooling device includes a cooling water pipe or a cooling jacket.
[0014] Preferably, the cooling water pipe is spirally wound on the outer wall of the hydrolysis tank.
[0015] Preferably, the drying unit includes a dryer, which is a paddle dryer, a rake dryer, or a film dryer.
[0016] Compared with the prior art, the beneficial effects of this utility model are as follows: by neutralizing and hydrolyzing the mixture of silicon powder, diatomaceous earth and trace amounts of chlorosilane, the chlorosilane is dissolved in water. Then, the silicon powder and diatomaceous earth are separated from the filtrate through two solid-liquid separation processes. The silicon powder and diatomaceous earth are collected for external processing, and the filtrate is passed into a clean water recovery unit for reuse. This not only avoids resource waste but also effectively reduces the cost of waste residue treatment. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of the structure of the reaction unit and the solid-liquid separation unit provided in the embodiments of this utility model;
[0019] Figure 2 A schematic diagram of the structure of the hydrolysis tank with a cooling jacket provided in an embodiment of this utility model;
[0020] Figure 3 A schematic diagram of the structure of the hydrolysis tank with cooling water pipes provided in the embodiment of this utility model.
[0021] Reference numerals: 10, hydrolysis tank; 101, cooling device; 20, neutralization reactor; 30, settling tank; 40, filter press; 50, circulating pump; 60, production water conveying device; 70, alkali conveying device. Detailed Implementation
[0022] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this invention. Therefore, the drawings and description are considered exemplary in nature and not restrictive.
[0023] In the description of this utility model, it should be understood that the terms "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0026] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0027] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.
[0028] like Figures 1-2 As shown, this utility model embodiment provides a diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment, including a drying unit, a reaction unit, a solid-liquid separation unit and a clean water recovery unit;
[0029] The reaction unit includes a hydrolysis tank 10 and a neutralization reactor 20 connected to the outlet of the hydrolysis tank 10. The inlet of the hydrolysis tank 10 is connected to the outlet of the drying unit.
[0030] The solid-liquid separation unit includes a sedimentation tank 30 and a filter press 40. The sedimentation tank 30 includes a first feed inlet, a supernatant outlet and a suspension outlet, and the filter press 40 includes a second feed inlet, a filtrate outlet and a filter residue outlet.
[0031] The first feed inlet is connected to the outlet of the neutralization reactor 20, the supernatant outlet and the filtrate outlet are both connected to the inlet of the clean water recovery unit, and the suspension outlet is connected to the second feed inlet of the filter press 40.
[0032] Specifically, the drying unit includes a dryer, which is a paddle dryer, a rake dryer, or a film dryer.
[0033] In actual use, both hydrolysis and neutralization reactions are continuous processes, requiring a continuous supply of production water and alkali solution. Specifically, the reaction unit also includes a production water conveying device 60 and an alkali solution conveying device 70. The production water conveying device 60 is connected to the inlet of the hydrolysis tank 10 and is used to continuously supply the production water required for hydrolysis. The alkali solution conveying device 70 is connected to the inlet of the neutralization reactor 20 and is used to continuously supply the alkali solution required for the neutralization reaction.
[0034] In use, the mixture from upstream is first dried to obtain a solid mixture. The solid mixture is then placed in a hydrolysis tank 10, and production water is added to the hydrolysis tank 10. Through hydrolysis, trace amounts of chlorosilane dissolve in the water to obtain an acidic mixture. The hydrolyzed acidic mixture is then fed into a neutralization reactor 20, and alkali solution is continuously added to the neutralization reactor 20 to carry out a neutralization reaction. The pH of the aqueous solution is adjusted to neutral to obtain a neutral mixture. The neutral mixture is then fed into a settling tank 30 and allowed to stand for 1 minute. The supernatant and suspension are separated by gravity settling. The supernatant is fed into a clean water recovery unit for recycling and reuse, while the suspension is fed into a filter press 40 for solid-liquid separation, separating the silica powder and diatomaceous earth from the filtrate.
[0035] The collected silica powder and diatomaceous earth are subject to external processing, including but not limited to external sales. Since diatomaceous earth and silica powder can be used as additives in cement manufacturing, external sales can effectively reduce waste disposal costs. The supernatant and filtrate obtained from solid-liquid separation are passed into a clean water recycling unit for reuse, effectively avoiding resource waste.
[0036] Furthermore, the hydrolysis tank 10 is connected to the neutralization reactor 20, and the neutralization reactor 20 is connected to the first feed inlet, the suspension outlet and the second feed inlet through conveying pipes. Each of these conveying pipes is equipped with a circulation pump 50 to control the flow rate of the mixture.
[0037] Since the hydrolysis of the mixture with the production water is an exothermic process, the temperature of the hydrolysis tank 10 needs to be controlled in actual use. The outer wall of the hydrolysis tank 10 is equipped with a cooling device 101. In this embodiment, the temperature inside the hydrolysis tank 10 is less than 50°C, which is optimal.
[0038] Specifically, the cooling device 101 may be, but is not limited to, a cooling water pipe or a cooling jacket, so as to introduce cooling water to cool the hydrolysis tank 10; when the cooling water pipe is used for cooling, in order to ensure that the cooling water pipe is in full contact with the hydrolysis tank 10 to ensure the cooling effect, the cooling water pipe is spirally wound on the outer wall of the hydrolysis tank 10.
[0039] It should be noted that the used cooling water can be recycled, which avoids both the waste of water resources and the waste of heat energy.
[0040] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment, comprising a drying unit, a reaction unit, a solid-liquid separation unit, and a clean water recovery unit, characterized in that: The reaction unit includes a hydrolysis tank (10) and a neutralization reactor (20) connected to the outlet of the hydrolysis tank (10). The inlet of the hydrolysis tank (10) is connected to the outlet of the drying unit. The solid-liquid separation unit includes a sedimentation tank (30) and a filter press (40). The sedimentation tank (30) includes a first feed inlet, a supernatant outlet and a suspension outlet. The filter press (40) includes a second feed inlet, a filtrate outlet and a filter residue outlet. The first feed inlet is connected to the outlet of the neutralization reactor (20), the supernatant outlet and the filtrate outlet are both connected to the inlet of the water recovery unit, and the suspension outlet is connected to the second feed inlet of the filter press (40).
2. The diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment according to claim 1, characterized in that: The hydrolysis tank (10) is connected to the neutralization reactor (20), the neutralization reactor (20) is connected to the first feed inlet, the suspension outlet and the second feed inlet through conveying pipes, and each conveying pipe is equipped with a circulation pump (50).
3. The diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment according to claim 1, characterized in that: The reaction unit also includes a production water conveying device (60) and an alkali conveying device (70), wherein the production water conveying device (60) is connected to the inlet of the hydrolysis tank (10) and the alkali conveying device (70) is connected to the inlet of the neutralization reactor (20).
4. The diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment according to claim 1, characterized in that: The outer wall of the hydrolysis tank (10) is provided with a cooling device (101).
5. The diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment according to claim 4, characterized in that: The cooling device (101) includes a cooling water pipe or a cooling jacket.
6. The diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment according to claim 5, characterized in that: The cooling water pipe is spirally wound on the outer wall of the hydrolysis tank (10).
7. The diatomaceous earth and silicon powder recovery system for polycrystalline silicon slag slurry treatment according to claim 1, characterized in that: The drying unit includes a dryer, which is a paddle dryer, a rake dryer, or a film dryer.