System for preparing thermal insulation material from polycrystalline silicon waste residues
By treating polysilicon waste residue through a scrubbing tower-reactor-calcining furnace system to generate high-value calcium silicate material, the problems of polysilicon production tail gas pollution and resource waste are solved, and low-energy resource utilization and environmentally friendly thermal insulation material production are realized.
Patent Information
- Application Number
- CN202520977499.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-19
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2035-05-19
AI Technical Summary
In the polysilicon production process, the direct emission of SiCl4 from the exhaust gas leads to environmental pollution and resource waste. Traditional treatment methods are energy-intensive and do not fully utilize resources.
An integrated system consisting of a scrubbing tower, a reaction vessel, and a calcining furnace is adopted to treat polycrystalline silicon waste residue with water and lime slurry to generate high-value calcium silicate materials, replacing the traditional high-temperature calcination process and achieving harmless treatment and resource utilization of exhaust gas.
This method enables the resource utilization of polycrystalline silicon waste residue, reduces energy consumption and production costs, minimizes environmental pollution, and generates high-strength calcium silicate insulation material.
Smart Images
Figure CN223931420U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a system for preparing thermal insulation materials, and more particularly to a system for preparing thermal insulation materials from polycrystalline silicon waste residue. Background Technology
[0002] This section provides only background information relevant to this disclosure and is not necessarily prior art.
[0003] During polysilicon production, the vented exhaust gas contains a large amount of SiCl4 (approximately 5–10% by volume). Direct emission of this gas will react with water to generate HCl gas and silica colloids, causing air and soil pollution and equipment corrosion. Traditional treatment methods include alkali neutralization and incineration. Currently, the main treatment method is to neutralize the exhaust gas with lime slurry solution through a scrubbing tower and then send it directly to a slag yard for disposal as waste residue.
[0004] The hydrolysis of chlorosilanes requires a large amount of alkaline solution (such as Ca(OH2)), resulting in high treatment costs. Furthermore, the hydrolysis products can only be treated as waste residue and cannot be effectively utilized, leading to resource waste. Current production processes for calcium silicate insulation materials mostly involve high-temperature calcination (>1000℃) of quartz sand (SiO2) and lime, which is energy-intensive and generates significant carbon emissions.
[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content
[0006] Purpose of the invention: The technical problem to be solved by this utility model is to provide a system for preparing thermal insulation materials from polycrystalline silicon waste residue, which addresses the shortcomings of the existing technology.
[0007] To address the aforementioned technical problems, this utility model discloses a system for preparing thermal insulation materials from polycrystalline silicon waste, comprising:
[0008] A scrubbing tower; the scrubbing tower is provided with a tail gas inlet in the middle, a water inlet and a lime slurry inlet at the bottom, and the bottom outlet is fluidly connected to the first slurry delivery pump through a slurry delivery valve.
[0009] The output port of the first external pump for slurry is divided into two paths: one path is fluidly connected to the spray head in the scrubbing tower, and the other path is fluidly connected to the reactor through the external slurry regulating valve.
[0010] The reactor is also equipped with a chlorosilane waste liquid inlet and a lime slurry inlet, and the bottom outlet of the reactor is fluidly connected to the sedimentation tank through a calcium silicate external pump;
[0011] The sedimentation tank is fluidly connected to a centrifuge and a shaping device in sequence for solid-liquid separation;
[0012] The solid output end of the shaping device is connected to the roasting furnace through a solid conveying channel.
[0013] Furthermore, the tail gas inlet of the scrubbing tower is fluidly connected to a tail gas buffer tank, which is used to store tail gas containing chlorosilane.
[0014] Furthermore, the water inlet and the lime slurry inlet are respectively equipped with a production water pipeline and a lime slurry feed pipeline, wherein the lime slurry feed pipeline is equipped with a lime slurry feed regulating valve for adjusting the ratio of lime slurry and water entering the scrubbing tower.
[0015] Furthermore, the spray heads inside the scrubbing tower are arranged in three levels from top to bottom to spray the material at the bottom of the scrubbing tower downwards.
[0016] Furthermore, the lime slurry inlet of the reactor is located at the top of the reactor and is fluidly connected to the lime slurry preparation tank containing lime slurry preparation through a preparation regulating valve.
[0017] Furthermore, the top of the scrubbing tower is provided with a gas outlet, which is fluidly connected to the tail gas absorption tank, for discharging the tail gas after the reaction in the scrubbing tower.
[0018] Furthermore, the centrifuge is also equipped with a deionized water inlet for introducing deionized water into the centrifuge.
[0019] Furthermore, the shaping device is an extruder.
[0020] Furthermore, the reactor is equipped with a heat preservation and stirring device.
[0021] Beneficial effects:
[0022] 1. This utility model converts SiCl4 tail gas, SiCl4 waste liquid and lime slurry into high-value calcium silicate material, replacing the traditional high-temperature process of quartz sand-lime, and realizing the co-utilization of waste.
[0023] 2. This utility model integrates a washing tower-reactor-calcining furnace system to achieve integrated tail gas treatment and material production.
[0024] 3. The reaction of this invention is carried out under mild conditions (no high-temperature calcination is required in the calcium silicate formation stage), which has the technical effect of low energy consumption control. Attached Figure Description
[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.
[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model.
[0027] In the diagram, 1 is the tail gas buffer tank, 2 is the lime slurry feed regulating valve, 3 is the scrubbing tower, 4 is the slurry delivery valve, 5 is the first slurry delivery pump, 6 is the tail gas absorption tank, 7 is the slurry delivery regulating valve, 8 is the lime slurry preparation tank, 9 is the preparation regulating valve, 10 is the reactor, 11 is the calcium silicate delivery pump, 12 is the settling tank, 13 is the centrifuge, 14 is the extruder, and 15 is the calcining furnace. Detailed Implementation
[0028] The overall concept of this utility model is as follows: to provide a system for preparing calcium silicate insulation material by reacting SiCl4 in polycrystalline silicon tail gas with lime milk, thereby achieving harmlessness and resource utilization of tail gas, while reducing the production cost of calcium silicate.
[0029] The technical solution of this utility model is as follows: A system for preparing thermal insulation materials from polycrystalline silicon waste residue, such as... Figure 1 As shown, it includes: a tail gas buffer tank 1 for storing tail gas containing chlorosilane, and the outlet of the tail gas buffer tank 1 is fluidly connected to the gas inlet in the middle of the scrubbing tower 3.
[0030] The lower part of the scrubbing tower 3 is also equipped with a lime slurry feed pipeline and a production water pipeline. The lime slurry feed pipeline is equipped with a lime slurry feed regulating valve 2, which is used to regulate the pH value input into the reactor of the scrubbing tower 3, i.e. the ratio of lime slurry to water.
[0031] The bottom of the scrubbing tower 3 is fluidly connected to the first slurry delivery pump 5 via a slurry delivery valve 4. The outlet of the first slurry delivery pump 5 is fluidly connected to the three spray lines at the top of the scrubbing tower 3, delivering the slurry from the bottom of the scrubbing tower 3 to the spray heads. The slurry is then sprayed from top to bottom at the top of the scrubbing tower 3, reacting with the input polycrystalline silicon tail gas. The gas produced by the reaction is discharged from the gas outlet at the top of the scrubbing tower 3 to the tail gas absorption tank 6 for treatment before being discharged.
[0032] The output end of the first external pump 5 is also fluidly connected to the reactor 10 through the external pump 7.
[0033] The reactor 10 is also equipped with a chlorosilane waste liquid inlet for inputting chlorosilane waste liquid into the reactor 10.
[0034] The top of the reactor 10 is fluidly connected to the lime slurry preparation tank 8 via the preparation regulating valve 9, which is used to input lime slurry into the reactor 10.
[0035] The reactor 10 is equipped with a steam insulation and stirring device to keep the substances inside the reactor 10 warm and stir them.
[0036] The bottom of the reactor 10 is fluidly connected to the settling tank 12 via a calcium silicate external pump 11.
[0037] The bottom of the sedimentation tank 12 is fluidly connected to the centrifuge 13, which is also equipped with a deionized water inlet for washing the sediment inside the centrifuge 13.
[0038] The centrifuge 13 is connected to the extruder 14 or the molding press to form a blank, which is then fed into the calcining furnace 15 to obtain the final product.
[0039] When the system is working:
[0040] 1. Tail gas pretreatment: The polycrystalline silicon venting tail gas is introduced into scrubbing tower 3, where water or Ca(OH)2 is sprayed to absorb SiCl4, initially generating silicic acid H2SiO3, CaSiO3, CaCl2 and other substances; (SiCl4 + 4H2O → H4SiO4 + 4HCl (further dehydration to generate H2SiO3), part of SiCl4 + 2Ca(OH)2 → CaSiO3 (calcium silicate) + 2CaCl2 + 2H2O);
[0041] 2. Secondary neutralization reaction:
[0042] Add the above liquid-solid mixture to the reactor, add lime milk (Ca(OH)2 suspension) to adjust the pH to 10–12, control the temperature at 40–80℃, and react for 2–4 hours.
[0043] H₂SiO₃ + Ca(OH)₂ → CaSiO₃ + 2H₂O
[0044] 3. Solid-liquid separation and washing
[0045] After the reaction is complete, the reaction slurry enters the sedimentation tank, and after settling, the supernatant (containing a small amount of CaCl2, which can be recycled) is separated; the precipitate is dehydrated by centrifuge and washed with deionized water until the Cl- content is <0.1%.
[0046] 4. Shaping and firing
[0047] Calcium silicate filter cake is mixed with reinforcing fibers (such as glass fiber, accounting for 5-10%) and formed into plates / blocks by an extruder or molding machine; the formed blanks are fed into a calcining furnace and calcined at 800-1000℃ for 1-3 hours to obtain high-strength calcium silicate insulation material.
[0048] Example:
[0049] 1. The chlorosilane tail gas enters the tail gas buffer tank 1 through the venting system, and then enters the scrubbing tower 3. The scrubbing tower 3 includes a three-stage spraying system, a lime milk feed pipeline, and a production water pipeline. The pH in the scrubbing tower 3 is adjusted to 6-7 by the lime milk feed regulating valve 2.
[0050] 2. After the tail gas enters the scrubbing tower 3, the gaseous chlorosilane is absorbed by the three-stage spray liquid delivered by the first external pump 5 of the slurry, and initially generates substances such as silicic acid H2SiO3, CaSiO3, and CaCl2. The tail gas is further purified by the tail gas absorption tank 6 at the top of the tower before being discharged into the atmosphere.
[0051] 3. The bottom of the tower is equipped with a slurry delivery valve 4 and a first slurry delivery pump 5. After the initial reaction, the slurry is sent to the reactor 10 via the first delivery pump 5 and the slurry delivery regulating valve 7.
[0052] 4. The reactor 10 is equipped with a steam insulation and stirring device. After the initial reaction, the slurry and chlorosilane waste liquid enter the reactor 10 and are mixed with the Ca(OH)2 suspension from the lime milk preparation tank 8 to adjust the pH to 10-12 and control the temperature to 40-80℃. After reacting for 2-4 hours, the calcium silicate suspension formed is sent to the sedimentation tank 12 via the calcium silicate external pump 11.
[0053] 5. After the calcium silicate suspension undergoes initial settling in settling tank 12, the wastewater is recycled and reused. Since the calcium silicate still contains a large amount of water and excessive Cl- levels after settling, the calcium silicate precipitate is sent to centrifuge 13. During centrifugation, deionized water is added for washing, resulting in a Cl- content of <0.1%. The water content of the calcium silicate precipitate is further removed by centrifuge 13.
[0054] 6. After mixing the calcium silicate filter cake with reinforcing fibers (such as glass fiber, accounting for 5-10%), the mixture is extruded through an extruder 14, which can also be a molding press, to form a plate / block shape. The formed blank is then fed into a calcining furnace 15 and calcined at 800-1000℃ for 1-3 hours to obtain a high-strength calcium silicate insulation material.
[0055] This utility model provides a systematic approach and method for preparing thermal insulation materials from polycrystalline silicon waste. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model. All components not explicitly stated in this embodiment can be implemented using existing technology.
Claims
1. A system for preparing thermal insulation materials from polycrystalline silicon waste, characterized in that, include: The scrubbing tower (3) is provided with a tail gas inlet in the middle, a water inlet and a lime milk inlet in the lower part, and the bottom outlet is fluidly connected to the first slurry delivery pump (5) through the slurry delivery valve (4). The output port of the first external pump (5) for slurry is divided into two paths. One path is fluidly connected to the spray head in the scrubbing tower (3), and the other path is fluidly connected to the reactor (10) through the external slurry regulating valve (7). The reactor (10) is also provided with a chlorosilane waste liquid inlet and a lime milk inlet. The bottom outlet of the reactor (10) is fluidly connected to the sedimentation tank (12) through a calcium silicate external pump (11). The sedimentation tank (12) is fluidly connected to the centrifuge (13) and the shaping device in sequence for solid-liquid separation; The solid output end of the shaping device is connected to the roasting furnace (15) through a solid conveying channel.
2. The system for preparing thermal insulation materials from polycrystalline silicon waste according to claim 1, characterized in that, The tail gas inlet of the scrubbing tower (3) is fluidly connected to the tail gas buffer tank (1), which is used to store tail gas containing chlorosilane.
3. The system for preparing thermal insulation materials from polycrystalline silicon waste according to claim 1, characterized in that, The water inlet and lime slurry inlet are respectively equipped with a production water pipeline and a lime slurry feed pipeline. The lime slurry feed pipeline is equipped with a lime slurry feed regulating valve (2) to regulate the ratio of lime slurry and water entering the scrubbing tower (3).
4. The system for preparing thermal insulation materials from polycrystalline silicon waste according to claim 1, characterized in that, The spray heads inside the scrubbing tower (3) are arranged in three levels from top to bottom to spray the material at the bottom of the scrubbing tower (3) downwards.
5. The system for preparing thermal insulation materials from polycrystalline silicon waste according to claim 1, characterized in that, The lime slurry inlet of the reactor (10) is located at the top of the reactor (10) and is fluidly connected to the lime slurry preparation tank (8) containing lime slurry preparation through the preparation regulating valve (9).
6. The system for preparing thermal insulation materials from polycrystalline silicon waste according to claim 1, characterized in that, The top of the scrubbing tower (3) is provided with a gas outlet, which is fluidly connected to the tail gas absorption tank (6) for discharging the tail gas after the reaction in the scrubbing tower (3).
7. The system for preparing thermal insulation materials from polycrystalline silicon waste according to claim 1, characterized in that, The centrifuge (13) is also provided with a deionized water inlet for inputting deionized water into the centrifuge (13).
8. The system for preparing thermal insulation materials from polycrystalline silicon waste according to claim 1, characterized in that, The shaping device is an extruder (14).
9. The system for preparing thermal insulation materials from polycrystalline silicon waste according to claim 1, characterized in that, The reactor (10) is equipped with a heat preservation device.
10. The system for preparing thermal insulation materials from polycrystalline silicon waste according to claim 1, characterized in that, The reactor (10) is equipped with a stirring device.