Treatment method and treatment device for cleaning water of polycrystalline silicon reduction furnace

Abstract

The invention provides a treatment method and a treatment device for cleaning water of a polycrystalline silicon reduction furnace, and the treatment method for the cleaning water of the polycrystalline silicon reduction furnace comprises the following steps: 1) filtering the cleaning water of the polycrystalline silicon reduction furnace to obtain filtrate; 2) carrying out first cleaning treatment on the silicon-calcium slag solid waste by using the filtrate to obtain cleaning wastewater; and 3) purifying the cleaning wastewater to obtain purified water. According to the method for treating the cleaning water of the polycrystalline silicon reduction furnace, the cleaning water of the polycrystalline silicon reduction furnace is filtered, the obtained filtrate is used for cleaning silicon-calcium slag solid waste again, and the requirement for a fresh water source is reduced through cyclic utilization, so that the overall water consumption is reduced, wastewater treatment is reduced, and the energy consumption is reduced. And the silicon-calcium slag solid waste is subjected to resource utilization, so that the economic benefit is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and particularly relates to a method and a device for treating the cleaning water of a polysilicon reduction furnace. Background Art

[0002] Polysilicon is a key material in the photovoltaic industry and the electronics industry. Its production process involves complex chemical reactions and high-temperature treatments. An important step is the gas-phase deposition reaction of trichlorosilane and hydrogen in the reduction furnace. This process not only produces high-purity polysilicon but also generates some by-products, such as amorphous silicon. These by-products usually adhere to the chassis and furnace wall of the reduction furnace and need to be cleaned regularly to maintain the normal operation of the equipment and the high purity of the product.

[0003] Currently, the commonly used cleaning method in the industry is to conduct a preliminary cleaning with a sodium hydroxide solution of high pH value and then rinse with demineralized water. The wastewater generated in this process contains impurities such as a small amount of amorphous silicon suspended solids and trace metal ions, and is usually directly discharged into the three-waste treatment system for treatment.

[0004] In the three-waste treatment system, the sludge formed after the wastewater is treated forms silicon-calcium slag solid waste through plate-frame pressure filtration. However, due to the relatively high chloride ion content in the silicon-calcium slag solid waste, its direct use in building materials, such as cement or non-fired bricks, will be restricted. To solve this problem, industrial water is usually used to backwash the silicon-calcium slag solid waste to reduce the chloride ion content therein to a standard that can be admixed into cement, thereby realizing the resource utilization of the solid waste. However, although this method is effective, it will significantly increase water consumption and reduce economic benefits. Therefore, how to achieve the resource utilization of solid waste while reducing water consumption has become an important direction for the current technological development. Summary of the Invention

[0005] The main object of the present invention is to provide a method for treating the cleaning water of a polysilicon reduction furnace, which can reduce water consumption, realize the resource utilization of silicon-calcium slag solid waste, and improve economic benefits.

[0006] The present invention also provides a device for treating the cleaning water of a polysilicon reduction furnace. Using this device to treat the cleaning water of a polysilicon reduction furnace can reduce water consumption, realize the resource utilization of silicon-calcium slag solid waste, and improve economic benefits.

[0007] The present invention also provides a polysilicon production system. Since this system includes the above-mentioned device for treating the cleaning water of a polysilicon reduction furnace, this system can reduce water consumption, realize the resource utilization of silicon-calcium slag solid waste, and improve economic benefits.

[0008] In the first aspect, the present invention provides a method for treating the cleaning water of a polysilicon reduction furnace, including the following steps:

[0009] 1) Filter the cleaning water of the polysilicon reduction furnace to obtain a filtrate;

[0010] 2) Use the filtrate to perform a first cleaning treatment on the calcium silicate slag solid waste to obtain cleaning wastewater;

[0011] 3) Purify the cleaning wastewater to obtain purified water.

[0012] The method for treating the cleaning water of the polysilicon reduction furnace as described above further includes: using an alkali solution to perform a second cleaning treatment on the filter medium used in the filtration treatment to obtain soluble silicate.

[0013] The method for treating the cleaning water of the polysilicon reduction furnace as described above uses the soluble silicate and the remaining alkali solution to neutralize acidic wastewater.

[0014] The method for treating the cleaning water of the polysilicon reduction furnace as described above, the first cleaning treatment includes at least N times of the first cleaning treatment, where N≥2.

[0015] The method for treating the cleaning water of the polysilicon reduction furnace as described above, the calcium silicate slag solid waste is derived from the purification treatment of wastewater; wherein, the wastewater is derived from the wastewater obtained by washing the waste gas scrubber and hydrolyzing high-boiling substances.

[0016] In a second aspect, the present invention provides a device for treating the cleaning water of a polysilicon reduction furnace, including a filtration unit, a cleaning unit, and a purification unit;

[0017] The first liquid outlet of the filtration unit is communicated with the first liquid inlet of the cleaning unit; the first liquid outlet of the cleaning unit is communicated with the liquid inlet of the purification unit.

[0018] The filtration unit of the device for treating the cleaning water of the polysilicon reduction furnace as described above further includes a filter medium for filtering the cleaning water of the polysilicon reduction furnace.

[0019] The device for treating the cleaning water of the polysilicon reduction furnace as described above further includes: a first storage unit, a second storage unit, and a third storage unit;

[0020] The first liquid outlet of the filtration unit is communicated with the first liquid inlet of the cleaning unit through the first storage unit;

[0021] The liquid inlet of the second storage unit is communicated with the second liquid outlet of the cleaning unit, and the liquid outlet of the second storage unit is communicated with the second liquid inlet of the cleaning unit; the liquid inlet of the third storage unit is communicated with the third liquid outlet of the cleaning unit, and the liquid outlet of the third storage unit is communicated with the third liquid inlet of the cleaning unit.

[0022] In a third aspect, the present invention provides a polysilicon production system, including a solid collection device and a treatment device for the cleaning water of the polysilicon reduction furnace as described above.

[0023] For the polysilicon production system as described above, the solid outlet of the treatment device for the cleaning water of the polysilicon reduction furnace is communicated with the solid inlet of the solid collection device; the solid outlet of the solid collection device is communicated with the solid inlet of the cleaning unit.

[0024] The treatment method for the cleaning water of the polysilicon reduction furnace provided by the present invention filters the cleaning water of the polysilicon reduction furnace, and the obtained filtrate is used again to clean the silicon-calcium slag solid waste. This recycling reduces the demand for fresh water sources, thereby reducing the overall water consumption, reducing wastewater treatment, and also enabling the resource utilization of the silicon-calcium slag solid waste, improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention or related technologies. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings according to these drawings without creative efforts.

[0026] Figure 1 It is a schematic diagram of a treatment device for the cleaning water of a polysilicon reduction furnace provided by the present invention.

[0027] Description of the reference numerals:

[0028] 1 - Filtering unit; 2 - Cleaning unit; 3 - Purifying unit; 4 - First storage unit; 5 - Second storage unit; 6 - Third storage unit; 7 - Solid collection device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0030] In the process of polysilicon production, trichlorosilane and hydrogen undergo a chemical vapor deposition reaction in a reduction furnace. While polysilicon is produced, some amorphous silicon adheres to the chassis and furnace wall of the reduction furnace. To maintain the normal operation of the equipment and the high purity of the product, the reduction furnace needs to be cleaned after production. Currently, in the industry, a sodium hydroxide solution with a pH value of about 13 is usually used for preliminary cleaning to remove the attached amorphous silicon and other impurities, and then demineralized water is used for rinsing. However, the wastewater generated by this cleaning process contains a small amount of amorphous silicon suspended solids and trace metal ions and other impurities, which are usually directly discharged into the three-waste treatment system, resulting in the underutilization of water resources.

[0031] In addition, the wastewater generated during the cleaning process is weakly acidic and contains fine silicon powder suspended solids. For other wastewater in polysilicon production, such as the wastewater generated during the washing of waste gas scrubbers and the hydrolysis of high-boiling substances, the pH value is less than 1, and the chloride ion content is as high as about 80,000 ppm. These two types of wastewater are usually not separately treated in the industry, and the separation of clear and turbid substances is not achieved, resulting in increased treatment difficulty and waste of resources.

[0032] The current treatment method not only increases the burden on the wastewater treatment system but also fails to effectively recover and reuse the valuable components therein. With the increasingly strict environmental protection regulations and the exacerbation of water resource shortage problems, how to optimize the wastewater treatment process, achieve the recycling of water resources, and the resource treatment of waste has become an urgent problem for polysilicon production enterprises. By improving wastewater treatment technology, not only can the production cost be reduced, but also the environmental impact can be reduced, and the sustainable development ability of the enterprise can be improved.

[0033] In a first aspect, the present invention provides a method for treating the cleaning water of a polysilicon reduction furnace, comprising the following steps:

[0034] 1) Filter the cleaning water of the polysilicon reduction furnace to obtain a filtrate;

[0035] 2) Use the filtrate to perform a first cleaning treatment on the silicon-calcium slag solid waste to obtain cleaning wastewater;

[0036] 3) Purify the cleaning wastewater to obtain purified water.

[0037] The method for treating the cleaning water of the polysilicon reduction furnace provided by the present invention can realize the resource utilization of the silicon-calcium slag solid waste, reduce water consumption, and improve economic benefits by using the filtered cleaning water of the polysilicon reduction furnace to clean the silicon-calcium slag solid waste and then purifying the cleaning wastewater.

[0038] Specifically, in step 1), it can be understood that the cleaning water of the polysilicon reduction furnace includes silicon powder, metal ions such as iron, aluminum, calcium, etc. By filtering the cleaning water of the polysilicon reduction furnace, large particle impurities such as silicon powder are removed to obtain a reusable filtrate.

[0039] In step 2), the above filtrate is used to perform the first cleaning on the calcium silicate slag solid waste, reducing the chloride ion content in the calcium silicate slag solid waste so that it can meet the blending requirements of cement or non-fired bricks, and the industrial water consumption can be reduced. The full utilization of the furnace barrel cleaning water is realized, the water consumption is reduced, and the wastewater treatment is reduced.

[0040] In step 3), the wastewater after cleaning is purified. This can not only make the cleaning water of the polysilicon reduction furnace be fully utilized, but also make this part of the cleaning water finally purified. The purified water can be used for washing waste gas. Specifically, the steps of purification treatment can include: first, the cleaning wastewater is sequentially subjected to neutralization treatment and natural sedimentation treatment, and then a coagulant, such as propylene glycol methyl ether acetate (PMA), is added for sedimentation treatment to achieve the purification treatment of the cleaning wastewater.

[0041] Thus, the treatment method of the cleaning water of the polysilicon reduction furnace provided by the present invention filters the cleaning water of the polysilicon reduction furnace, and the obtained filtrate is used again for cleaning the calcium silicate slag solid waste. This kind of recycling reduces the demand for fresh water sources, thereby reducing the overall water consumption, reducing the wastewater treatment, and also making the calcium silicate slag solid waste be resourcefully utilized, improving the economic benefits.

[0042] In some embodiments of the present invention, it further includes: using an alkali solution to perform a second cleaning treatment on the filter medium used for the filtration treatment to obtain soluble silicate.

[0043] It can be understood that as the cleaning water of the polysilicon reduction furnace is filtered, the internal and external pressure difference of the filter medium, such as the filter cloth, will increase. Using an alkali solution, such as a sodium hydroxide solution with a mass percentage content of 10%, to clean the filter medium, sodium hydroxide can react with the silicon powder on the filter medium to generate sodium silicate, and sodium silicate is easily soluble in water, which can maintain the permeability and efficiency of the filter medium, realize the regeneration of the filter medium, thereby prolonging its service life and reducing the replacement frequency and cost.

[0044] In some embodiments of the present invention, the soluble silicate and the remaining alkali solution are used to neutralize acidic wastewater, which can make full use of the by-products and remaining substances generated in the production process, reduce waste, and realize the recycling of resources. It also reduces the demand for externally purchased neutralizing agents, thereby reducing the chemical cost of wastewater treatment.

[0045] In some embodiments of the present invention, the first cleaning treatment includes at least N times of the first cleaning treatment, where N≥2.

[0046] Multiple cleanings can more effectively remove impurities in the calcium silicate slag, such as chloride ions and residues, ensure the thoroughness of cleaning, and improve the purity and quality of the solid waste.

[0047] During the first cleaning process, the calcium silicate slag solid waste can be first subjected to the first cleaning treatment with the cleaning wastewater that has undergone N times of the first cleaning treatment, and then successively with the cleaning wastewater that has undergone N - 1 times, N - 2 times, and so on, 1 time of cleaning. This can effectively remove impurities and residues in the calcium silicate slag solid waste, reduce the demand for clean water, achieve efficient recycling of water resources, and reduce the water treatment cost during the cleaning process.

[0048] In some embodiments of the present invention, the calcium silicate slag solid waste is derived from the purification treatment of wastewater; wherein, the wastewater is derived from the wastewater obtained from the exhaust gas scrubbing tower and the hydrolysis of high boilers.

[0049] During the process of purifying the wastewater obtained from the exhaust gas scrubbing tower and the hydrolysis of high boilers, the silicon and calcium components in the wastewater can be recovered and converted into calcium silicate slag solid waste. This resource utilization not only reduces waste emissions but also brings additional economic value. Moreover, the harmful substances and heavy metal ions in the wastewater are removed or fixed in the calcium silicate slag, reducing the environmental pollution risk and ensuring that the discharged water quality meets the environmental protection standards.

[0050] In a second aspect, the present invention provides a treatment device for the cleaning water of a polysilicon reduction furnace, including a filtration unit 1, a cleaning unit 2, and a purification unit 3;

[0051] The first liquid outlet of the filtration unit 1 is communicated with the first liquid inlet of the cleaning unit 2; the first liquid outlet of the cleaning unit 2 is communicated with the liquid inlet of the purification unit 3.

[0052] In the present invention, the filtration unit 1 can be a plate and frame filter press, the cleaning unit 2 can also be a plate and frame filter press, and the purification unit 3 can be a wastewater treatment device.

[0053] Specifically, the cleaning water of the polysilicon reduction furnace is filtered in the filtration unit 1 to obtain a filtrate; the filtrate is output from the first liquid outlet of the filtration unit 1 and enters the cleaning unit 2 through the first liquid inlet of the cleaning unit 2, where it is used to perform the first cleaning treatment on the calcium silicate slag solid waste to obtain cleaning wastewater; the cleaning wastewater is output from the first liquid outlet of the cleaning unit 2 and enters the purification unit 3 through the liquid inlet of the purification unit 3 for purification treatment to obtain purified water.

[0054] The treatment device for the cleaning water of the polysilicon reduction furnace of the present invention filters the cleaning water of the polysilicon reduction furnace, and the obtained filtrate is reused to clean the calcium silicate slag solid waste. This recycling reduces the demand for fresh water sources, thereby reducing the overall water consumption, reducing wastewater treatment, and also enabling the resource utilization of the calcium silicate slag solid waste, improving economic benefits.

[0055] In some embodiments of the present invention, the filtration unit 1 further includes a filter medium for filtering the cleaning water of the polysilicon reduction furnace.

[0056] In the present invention, the filter medium in the filtering unit 1 can remove solid particles and suspended matters in the cleaning water, such as silicon powder and other impurities, thereby improving the purity of the filtrate, providing a higher-quality water source for subsequent treatment steps, and also avoiding the blockage of the cleaning unit 2.

[0057] In some embodiments of the present invention, the treatment device for the cleaning water of the polysilicon reduction furnace further includes: a first storage unit 4, a second storage unit 5, and a third storage unit 6; the first liquid outlet of the filtering unit 1 is communicated with the first liquid inlet of the cleaning unit 2 through the first storage unit 4.

[0058] The liquid inlet of the second storage unit 5 is communicated with the second liquid outlet of the cleaning unit 2, and the liquid outlet of the second storage unit 5 is communicated with the second liquid inlet of the cleaning unit 2; the liquid inlet of the third storage unit 6 is communicated with the third liquid outlet of the cleaning unit 2, and the liquid outlet of the third storage unit 6 is communicated with the third liquid inlet of the cleaning unit 2.

[0059] The first storage unit 4, the second storage unit 5, and the third storage unit 6 in the present invention can all be washing sinks.

[0060] In the present invention, the filtrate is output from the first liquid outlet of the filtering unit 1, enters the first storage unit 4 through the liquid inlet of the first storage unit 4 for storage, then is output from the liquid outlet of the first storage unit 4, enters the cleaning unit 2 through the first liquid inlet of the cleaning unit 2 for the first first cleaning treatment of the silicon-calcium slag solid waste to obtain the first cleaning wastewater. The first cleaning wastewater is output from the second liquid outlet of the cleaning unit 2, enters the second storage unit 5 through the liquid inlet of the second storage unit 5 for storage, then is output from the liquid outlet of the second storage unit 5, enters the cleaning unit 2 through the second liquid inlet of the cleaning unit 2 for the second first cleaning treatment to obtain the second cleaning wastewater. The second cleaning wastewater is output from the third liquid outlet of the cleaning unit 2, enters the third storage unit 6 through the liquid inlet of the third storage unit 6 for storage, then is output from the liquid outlet of the third storage unit 6, enters the cleaning unit 2 through the third liquid inlet of the cleaning unit 2 for the third first cleaning treatment to obtain the third cleaning wastewater. The third cleaning wastewater is output from the first liquid outlet of the cleaning unit 2, enters the purification unit 3 through the liquid inlet of the purification unit 3 for purification treatment to obtain purified water. Multiple cleanings can more effectively remove impurities in the silicon-calcium slag, such as chloride ions and residues, ensure the thoroughness of cleaning, and improve the purity and quality of the solid waste.

[0061] In subsequent cleaning processes, the waste cleaning water in the third storage unit 6 can be first used to clean the calcium silicate slag solid waste, and then the waste cleaning water in the second storage unit 5 and the first storage unit 4 can be successively used to clean the calcium silicate slag solid waste. This can further effectively remove impurities and residues in the calcium silicate slag solid waste, reduce the demand for clean water, achieve efficient recycling of water resources, and reduce the water treatment cost during the cleaning process.

[0062] In a third aspect, the present invention provides a polysilicon production system, including a solid collection device 7 and a processing device for the cleaning water of the polysilicon reduction furnace as described above.

[0063] In the present invention, the solid collection device 7 can be a sludge pond, which can collect the sludge obtained by purifying the waste water, and this sludge is the source of the calcium silicate slag solid waste.

[0064] The polysilicon production system of the present invention includes a processing device for the cleaning water of the polysilicon reduction furnace as described above. Therefore, this system can reduce water consumption, achieve resource utilization of the calcium silicate slag solid waste, and improve economic benefits.

[0065] In some embodiments of the present invention, the solid outlet of the processing device for the cleaning water of the polysilicon reduction furnace is communicated with the solid inlet of the solid collection device 7; the solid outlet of the solid collection device 7 is communicated with the solid inlet of the cleaning unit 2.

[0066] In the present invention, the solid outlet of the processing device for the cleaning water of the polysilicon reduction furnace is the solid outlet of the purification unit 3. The waste cleaning water is purified in the purification unit 3 to obtain calcium silicate slag solid waste, which is output from the solid outlet of the purification unit 3, enters the solid collection device 7 through the solid inlet of the solid collection device 7, is mixed with the calcium silicate slag solid waste in the solid collection device 7, and then is output from the solid outlet of the solid collection device 7 and enters the cleaning unit 2 through the solid inlet of the cleaning unit 2 to wait for cleaning, thus realizing the resource utilization of the calcium silicate slag solid.

[0067] Hereinafter, the technical solution of the present invention will be further described in conjunction with specific embodiments.

[0068] Example 1

[0069] The device in this example is a processing device for the cleaning water of the polysilicon reduction furnace, as Figure 1 shown, including a filtering unit 1 (the first plate and frame filter press); a cleaning unit 2 (the second plate and frame filter press); a purification unit 3 (a waste water treatment device); a first storage unit 4 (the first washing tank); a second storage unit 5 (the second washing tank); a third storage unit 6 (the third washing tank); a solid collection device 7 (a sludge pond).

[0070] Among them, the first liquid outlet of the filtering unit 1 is communicated with the first liquid inlet of the cleaning unit 2 through the first storage unit 4, the liquid inlet of the second storage unit 5 is communicated with the second liquid outlet of the cleaning unit 2, and the liquid outlet of the second storage unit 5 is communicated with the second liquid inlet of the cleaning unit 2; the liquid inlet of the third storage unit 6 is communicated with the third liquid outlet of the cleaning unit 2, and the liquid outlet of the third storage unit 6 is communicated with the third liquid inlet of the cleaning unit 2. The first liquid outlet of the cleaning unit 2 is communicated with the liquid inlet of the purification unit 3, the solid outlet of the purification unit 3 is communicated with the solid inlet of the solid collection device 7, and the solid outlet of the solid collection device 7 is communicated with the solid inlet of the cleaning unit 2.

[0071] Specifically, the cleaning water of the polysilicon reduction furnace enters the filtering unit 1 from the first liquid inlet of the filtering unit 1 for filtering treatment to obtain filtrate; the filtrate is output from the first liquid outlet of the filtering unit 1, enters the first storage unit 4 through the liquid inlet of the first storage unit 4 for storage, and then is output from the liquid outlet of the first storage unit 4, enters the cleaning unit 2 through the first liquid inlet of the cleaning unit 2 for the first first cleaning treatment of the calcium silicate solid waste to obtain the first cleaning wastewater. The first cleaning wastewater is output from the second liquid outlet of the cleaning unit 2, enters the second storage unit 5 through the liquid inlet of the second storage unit 5 for storage, and then is output from the liquid outlet of the second storage unit 5, enters the cleaning unit 2 through the second liquid inlet of the cleaning unit 2 for the second first cleaning treatment to obtain the second cleaning wastewater. The second cleaning wastewater is output from the third liquid outlet of the cleaning unit 2, enters the third storage unit 6 through the liquid inlet of the third storage unit 6 for storage, and then is output from the liquid outlet of the third storage unit 6, enters the cleaning unit 2 through the third liquid inlet of the cleaning unit 2 for the third first cleaning treatment to obtain the third cleaning wastewater. The third cleaning wastewater is output from the first liquid outlet of the cleaning unit 2, enters the purification unit 3 through the liquid inlet of the purification unit 3 for purification treatment to obtain purified water and calcium silicate solid waste. The calcium silicate solid waste is output from the solid outlet of the purification unit 3, enters the solid collection device 7 through the solid inlet of the solid collection device 7, and after being mixed with the calcium silicate solid waste in the solid collection device 7 (obtained from the purification treatment of the wastewater from the waste gas scrubbing tower and the hydrolysis of high boilers), is output from the solid outlet of the solid collection device 7 and enters the cleaning unit 2 through the solid inlet of the cleaning unit 2 to wait for cleaning. The cleaned calcium silicate solid waste can be used for blending in cement or non-fired bricks.

[0072] The filtering unit 1 further includes a filtering medium (filter cloth). The sodium hydroxide solution with a mass percentage content of 10% enters the filtering unit 1 from the second liquid inlet of the filtering unit 1 for the second cleaning treatment of the filtering medium to obtain soluble silicate; the soluble silicate and the remaining sodium hydroxide solution are used to neutralize acidic wastewater.

[0073] Comparative Example 1

[0074] In the treatment method of the cleaning water of the polysilicon reduction furnace in Comparative Example 1, the cleaning water of the polysilicon reduction furnace was directly purified, and industrial water was used to clean the silicon-calcium slag solid waste.

[0075] Compared with Comparative Example 1, Example 1 can save 1.5 tons of industrial water for treating 1 ton of silicon-calcium slag solid waste.

[0076] Compared with the comparative example, the treatment method of the cleaning water of the polysilicon reduction furnace provided by the present invention filters the cleaning water of the polysilicon reduction furnace, and the obtained filtrate is reused to clean the silicon-calcium slag solid waste. This recycling reduces the demand for fresh water sources, thereby reducing the overall water consumption, reducing wastewater treatment, and also enabling the resource utilization of the silicon-calcium slag solid waste, improving economic benefits.

[0077] Finally, it should be noted that: After considering the specification and practicing the invention disclosed herein, those skilled in the art will easily think of other embodiments of the present invention. The present invention is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include the common general knowledge or conventional technical means in the technical field not disclosed in the present invention. It is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A method for treating cleaning water of a polysilicon reduction furnace, characterized in that, It includes the following steps: 1) Filter the cleaning water of the polysilicon reduction furnace to obtain a filtrate; 2) Use the filtrate to perform a first cleaning treatment on the silicon-calcium slag solid waste to obtain cleaning wastewater; 3) Purify the cleaning wastewater to obtain purified water.

2. The treatment method of the cleaning water of the polysilicon reduction furnace according to claim 1, characterized in that, It further includes: Use an alkali solution to perform a second cleaning treatment on the filter medium used in the filtering treatment to obtain soluble silicate.

3. The treatment method of the cleaning water of the polysilicon reduction furnace according to claim 2, wherein, Use the soluble silicate and the remaining alkali solution to neutralize acidic wastewater.

4. The treatment method of the cleaning water of the polysilicon reduction furnace according to any one of claims 1-3, characterized in that, The first cleaning treatment includes at least N times of the first cleaning treatment, where N≥2.

5. The treatment method of the cleaning water of the polysilicon reduction furnace according to any one of claims 1-4, characterized in that, The silicon-calcium slag solid waste is derived from the purification treatment of wastewater; wherein, the wastewater is derived from the wastewater obtained by washing the waste gas in the scrubber and hydrolyzing high-boiling substances.

6. A treatment device for the cleaning water of a polysilicon reduction furnace, characterized in that, It includes a filtering unit, a cleaning unit and a purification unit; The first liquid outlet of the filtering unit is communicated with the first liquid inlet of the cleaning unit; the first liquid outlet of the cleaning unit is communicated with the liquid inlet of the purification unit.

7. The treatment device for the cleaning water of the polysilicon reduction furnace according to claim 6, characterized in that, The filtering unit further includes a filter medium for filtering the cleaning water of the polysilicon reduction furnace.

8. The treatment device for the cleaning water of the polysilicon reduction furnace according to claim 6 or 7, characterized in that It further includes: A first storage unit, a second storage unit and a third storage unit; The first liquid outlet of the filtering unit is communicated with the first liquid inlet of the cleaning unit through the first storage unit; The liquid inlet of the second storage unit is communicated with the second liquid outlet of the cleaning unit, and the liquid outlet of the second storage unit is communicated with the second liquid inlet of the cleaning unit; the liquid inlet of the third storage unit is communicated with the third liquid outlet of the cleaning unit, and the liquid outlet of the third storage unit is communicated with the third liquid inlet of the cleaning unit.

9. A polysilicon production system, characterized in that, It includes a solid collection device and a treatment device for the cleaning water of the polysilicon reduction furnace according to any one of claims 6-8.

10. The polysilicon production system according to claim 9, characterized in that, The solid outlet of the treatment device for the cleaning water of the polysilicon reduction furnace is communicated with the solid inlet of the solid collection device; the solid outlet of the solid collection device is communicated with the solid inlet of the cleaning unit.

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