Method for preparing ammonium bifluoride through combined treatment of fluorine and ammonia in photovoltaic industry

Abstract

The invention relates to the technical field of photovoltaics, in particular to a method for preparing ammonium bifluoride through combined treatment of fluorine and ammonia in the photovoltaic industry, which comprises a fluorine-containing waste liquid delivery pipe, an ammonia-containing waste gas absorption device, a membrane type solid-liquid concentration and separation device, a pH regulating tank, evaporation and concentration equipment, crystallization equipment and drying equipment, according to the method, the high-concentration fluorine-containing wastewater and ammonia-containing waste gas can be subjected to combined treatment, so that the fluorine-containing wastewater and ammonia-containing waste gas of a photovoltaic enterprise are subjected to resource recovery, and the environmental protection cost of the enterprise is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaics, and in particular to a method for preparing ammonium bifluoride by combined treatment of fluorine and ammonia in the photovoltaic industry. Background Art

[0002] Photovoltaic (solar photovoltaic power generation system) is a power generation system that converts the radiation energy of sunlight into electrical energy. Among them, solar photovoltaic cells are composed of photovoltaic chips made of monocrystalline silicon, polycrystalline silicon, gallium arsenide and other materials plus a protective layer. The photovoltaic industry produces a large amount of high-concentration fluorine-containing wastewater in the process of battery production, mainly from the two processes of texturing and etching. In order to avoid environmental pollution caused by direct discharge, it is usually necessary to render it harmless before discharge.

[0003] At present, flocculation and sedimentation method is used to treat fluorine-containing wastewater, and a large amount of reagents such as lime, PAC, PAM, etc. are added for flocculation and sedimentation treatment. Although the process is simple, the cost of using reagents is very high and the amount of sludge is large (the sludge needs to be outsourced for treatment at a fee). It is not scientific from the perspective of environmental protection and economy. Therefore, a method for preparing ammonium bifluoride by combined treatment of fluorine and ammonia in the photovoltaic industry is proposed, so as to facilitate the combined treatment of high-concentration fluorine-containing wastewater and ammonia waste gas, so that the fluorine-containing wastewater of photovoltaic enterprises can be recycled as resources, reducing the environmental protection costs of enterprises. Summary of the invention

[0004] In view of the problems in the prior art, the present invention provides a method for preparing ammonium bifluoride by combined treatment of fluorine and ammonia in the photovoltaic industry, so as to facilitate the combined treatment of high-concentration fluorine-containing wastewater and ammonia waste gas, so that the fluorine-containing wastewater of photovoltaic enterprises can be recycled as resources, thereby reducing the environmental protection costs of the enterprises.

[0005] The technical solution adopted by the present invention to solve its technical problems is a method for preparing ammonium bifluoride by fluorine-ammonia combined treatment in the photovoltaic industry, comprising a fluorine-containing waste liquid conveying pipe, an ammonia-containing waste gas absorption device, a membrane solid-liquid concentration and separation device, a pH adjusting tank, an evaporation and concentration device, a crystallization device and a drying device, wherein the liquid outlet end of the fluorine-containing waste liquid conveying pipe is connected to the liquid inlet end of the ammonia-containing waste gas absorption device, the gas inlet end of the ammonia-containing waste gas absorption device is provided with an ammonia-containing waste gas pipeline for conveying ammonia-containing waste gas, the liquid outlet end of the ammonia-containing waste gas absorption device is connected to the liquid inlet end of the membrane solid-liquid concentration and separation device, the water filtration and drainage end of the membrane solid-liquid concentration and separation device is connected to the pH adjusting tank through a pipeline, and the waste liquid drainage end of the membrane solid-liquid concentration and separation device is connected to the feed end of a centrifugal separation device through a pipeline.

[0006] By adopting the above technical scheme, the ammonium bifluoride product can be prepared by subjecting high-concentration fluorine-containing wastewater to a series of treatments such as ammonia-containing waste gas absorption, filtration, pH value adjustment, evaporation concentration, crystallization and drying by means of fluorine-ammonia combined treatment. In addition, the method of absorbing ammonia-containing waste gas with hydrofluoric acid waste liquid can replace the original waste gas treatment process of absorbing ammonia-containing waste gas with sulfuric acid, dissolve the silicon dioxide in the ammonia-containing waste gas, reduce the cleaning frequency of the customer's waste gas tower, and enable the fluorine-containing wastewater and ammonia-containing waste gas of photovoltaic enterprises to be recycled as resources, thereby reducing the environmental protection costs of the enterprises.

[0007] Specifically, the liquid outlet of the pH adjusting tank is connected to the evaporation concentration device through a pipeline, the liquid outlet of the evaporation concentration device is connected to the liquid inlet of the crystallization device through a pipeline, and the discharge end of the crystallization device is connected to the drying device through a pipeline.

[0008] By adopting the above technical solution, it is convenient to add high-concentration fluorine-containing wastewater into the pH adjustment tank to adjust the pH value to 0-5.

[0009] Specifically, the waste liquid outlet of the evaporation and concentration equipment is connected to a waste liquid transfer tank via a pipeline, and the waste liquid outlet of the waste liquid transfer tank is connected to a second wastewater station via a pipeline.

[0010] By adopting the above technical solution, the waste liquid generated during the crystallization and centrifugal separation process can be transferred and recycled.

[0011] Specifically, the evaporation concentration equipment includes an evaporator, the crystallization equipment includes a crystallizer and a centrifuge, and the liquid outlet end of the evaporator is connected to the crystallizer, and the material outlet end of the crystallizer is connected to the centrifuge, the drying equipment includes a dryer, and the material outlet end of the centrifuge is connected to the material feed end of the dryer through a pipeline, and the liquid outlet end of the centrifuge is connected to the waste liquid transfer tank.

[0012] By adopting the above technical scheme, the waste liquid with a pH value of 0-5 can be evaporated, concentrated, crystallized, centrifuged and dried to prepare the ammonium bifluoride product.

[0013] Specifically, the waste liquid outlet of the centrifugal separation device is connected to a water washing storage tank via a pipeline, and the liquid outlet of the water washing storage tank is connected to a first wastewater station via a pipeline.

[0014] By adopting the above technical solution, the waste liquid generated by water washing and centrifugal separation can be fully stirred and homogenized and then transported to the first wastewater station for recycling and treatment.

[0015] Specifically, step 1: adjusting pH value by waste gas absorption: pumping high-concentration fluorine-containing waste water into an ammonia-containing waste gas absorption device (2) through a fluorine-containing waste liquid delivery pipe (1), and then passing ammonia-containing waste gas into the fluorine-containing waste water through an ammonia-containing waste gas pipeline (201) for absorption until the pH value of the fluorine-containing waste water is 7-14, and treating the ammonia-containing waste gas by adjusting the pH value. When the pH value is between 0-4, the silicon dioxide in the ammonia-containing waste gas can be dissolved, thereby reducing the frequency of cleaning the waste gas tower;

[0016] Step 2: Filtration: Pump the waste liquid with a pH value of 7-14 to the membrane solid-liquid concentration and separation device (3) for filtration treatment;

[0017] Step 3: pH adjustment: pump the filtered wastewater with a pH value of 7-14 into the pH adjustment tank, and then add high-concentration fluoride-containing wastewater to adjust the pH value to 0-5;

[0018] Step 4: Evaporation and concentration: The waste liquid with a pH value of 0-5 is pumped into the evaporation and concentration equipment (8) for evaporation and concentration treatment, the evaporation temperature is 30-200° C. The condensed water generated during the evaporation process is discharged into the waste liquid transfer tank (9) for collection, and the concentrated liquid generated is collected in the concentrated liquid collection tank;

[0019] Step 5: Crystallization: The concentrated liquid in the collection tank is continuously pumped into the crystallization equipment (11);

[0020] Step 6: Drying: The crystallized material is directly pumped into the centrifuge of the centrifugal separation equipment (5) for centrifugal separation. The solid after centrifugal separation enters the drying equipment (12) through a conveyor belt for drying. The drying temperature is maintained at 60-300° C. and the moisture content after drying is less than 0-5%.

[0021] By adopting the above technical scheme and utilizing the fluorine-ammonia combined treatment method, high-concentration fluorine-containing wastewater is subjected to a series of treatments such as waste gas absorption, filtration, pH value adjustment, evaporation concentration, crystallization and drying to prepare ammonium bifluoride products, so that the fluorine-containing wastewater and ammonia waste gas of photovoltaic enterprises can be jointly treated and recycled as resources, replacing the traditional method of adding a large amount of reagents for flocculation and precipitation treatment, thereby reducing the environmental protection costs of enterprises.

[0022] Beneficial effects of the present invention:

[0023] 1. The method for preparing ammonium bifluoride by fluorine-ammonia combined treatment in the photovoltaic industry described in the present invention treats the ammonia-containing waste gas by adjusting the pH value through the fluorine-containing waste liquid delivery pipe, the ammonia-containing waste gas absorption device, the membrane solid-liquid concentration separation device and the centrifugal separation equipment. Because the ammonia-containing waste gas contains silicon dioxide dust, the original process front-end treatment can only remove 95% of the dust, resulting in the original waste gas treatment process using sulfuric acid to absorb the ammonia-containing waste gas. The method normally needs to be cleaned once every six months. However, the method uses hydrofluoric acid waste liquid for absorption. When the pH value is 0-4, the silicon dioxide in the ammonia-containing waste gas can be dissolved, thereby reducing the cleaning frequency of the waste gas tower;

[0024] 2. The method for preparing ammonium bifluoride by fluorine-ammonia combined treatment in the photovoltaic industry described in the present invention can utilize the fluorine-ammonia combined treatment method to complete the treatment of fluorine-containing wastewater with different concentrations and different components by means of a fluorine-containing waste liquid delivery pipe, an ammonia-containing waste gas absorption device, a membrane solid-liquid concentration separation device, a pH adjustment tank, a centrifugal separation device, an evaporation concentration device, a crystallization device and a drying device, and subject the fluorine-containing wastewater to a series of processes such as waste gas absorption, filtration, pH value adjustment, evaporation concentration, crystallization and drying.

[0025] 3. The method for preparing ammonium bifluoride by combined fluorine and ammonia treatment in the photovoltaic industry described in the present invention controls parameters such as the flow rate of ammonia-containing waste gas and fluorine-containing waste water, pH value, steam volume, etc., and utilizes fluorine-containing waste water of different concentrations and components to achieve the preparation of ammonium bifluoride products, so that the fluorine-containing waste water and ammonia waste gas of photovoltaic enterprises can be recycled as resources, thereby reducing the environmental protection costs of the enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0027] Figure 1 It is a schematic diagram of the process of the present invention;

[0028] In the figure: 1. Fluorine-containing waste liquid conveying pipe; 2. Ammonia-containing waste gas absorption device; 201. Ammonia-containing waste gas pipeline; 3. Membrane solid-liquid concentration and separation device; 4. pH adjustment tank; 5. Centrifugal separation equipment; 6. Water washing storage tank; 7. First wastewater station; 8. Evaporation concentration equipment; 9. Waste liquid transfer tank; 10. Second wastewater station; 11. Crystallization equipment; 12. Drying equipment. DETAILED DESCRIPTION

[0029] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0030] In order to facilitate the combined treatment of high-concentration fluorine-containing wastewater and ammonia waste gas, the fluorine-containing wastewater and ammonia waste gas of photovoltaic enterprises can be recycled and the environmental protection costs of enterprises can be reduced. Figure 1 As shown, a method for preparing ammonium bifluoride by fluorine-ammonia combined treatment in the photovoltaic industry described in the present invention comprises a fluorine-containing waste liquid conveying pipe 1, an ammonia-containing waste gas absorption device 2, a membrane solid-liquid concentration and separation device 3, a pH adjusting tank 4, an evaporation concentration device 8, a crystallization device 11 and a drying device 12, wherein the liquid outlet end of the fluorine-containing waste liquid conveying pipe 1 is connected to the liquid inlet end of the ammonia-containing waste gas absorption device 2, the gas inlet end of the ammonia-containing waste gas absorption device 2 is provided with an ammonia-containing waste gas pipeline 201 for conveying ammonia-containing waste gas, the liquid outlet end of the ammonia-containing waste gas absorption device 2 is connected to the liquid inlet end of the membrane solid-liquid concentration and separation device 3, the filtered water discharge end of the membrane solid-liquid concentration and separation device 3 is connected to the pH adjusting tank 4 through a pipeline, and the waste liquid discharge end of the membrane solid-liquid concentration and separation device 3 is connected to the feed end of the centrifugal separation device 5 through a pipeline.

[0031] When in use, through the membrane solid-liquid concentration and separation device 3, the pH adjustment tank 4, the centrifugal separation equipment 5, the evaporation concentration equipment 8, the crystallization equipment 11 and the drying equipment 12, the fluorine-ammonia combined treatment method can be used to prepare the ammonium bifluoride product by subjecting the high-concentration fluorine-containing waste water to a series of treatments such as ammonia-containing waste gas absorption, filtration, pH value adjustment, evaporation concentration, crystallization and drying. In addition, the method of absorbing the ammonia-containing waste gas with hydrofluoric acid waste liquid can replace the original waste gas treatment process of absorbing the ammonia-containing waste gas with sulfuric acid, dissolve the silicon dioxide in the ammonia-containing waste gas, reduce the cleaning frequency of the customer's waste gas tower, so that the fluorine-containing waste water of the photovoltaic enterprise can be recycled as a resource, and the environmental protection cost of the enterprise can be reduced.

[0032] For example, Figure 1 As shown, the present invention also includes that the liquid outlet end of the pH adjusting tank 4 is connected to the evaporation concentration device 8 through a pipeline, the liquid outlet end of the evaporation concentration device 8 is connected to the liquid inlet end of the crystallization device 11 through a pipeline, and the discharge end of the crystallization device 11 is connected to the drying device 12 through a pipeline.

[0033] When in use, the pH value is adjusted to 0-5 by adding high-concentration fluorine-containing wastewater into the pH adjustment tank 4.

[0034] For example, Figure 1 As shown, the present invention also includes that the waste liquid outlet of the evaporation concentration device 8 is connected to a waste liquid transfer tank 9 through a pipeline, and the outlet of the waste liquid transfer tank 9 is connected to a second wastewater station 10 through a pipeline.

[0035] When in use, the waste liquid generated during the crystallization and centrifugal separation process can be transferred and recycled through the waste liquid transfer tank 9 and the second waste water station 10.

[0036] For example, Figure 1As shown, the present invention also includes that the evaporation concentration equipment 8 includes an evaporator, the crystallization equipment 11 includes a crystallizer and a centrifuge, and the liquid outlet end of the evaporator is connected to the crystallizer, and the material outlet end of the crystallizer is connected to the centrifuge, the drying equipment 12 includes a dryer, and the material outlet end of the centrifuge is connected to the material feed end of the dryer through a pipeline, and the liquid outlet end of the centrifuge is connected to the waste liquid transfer tank 9.

[0037] When in use, the waste liquid with a pH value of 0-5 can be evaporated, concentrated, crystallized, centrifugally separated and dried through an evaporator, a crystallizer, a centrifuge and a dryer, so as to prepare an ammonium bifluoride product.

[0038] For example, Figure 1 As shown, the present invention also includes that the waste liquid outlet end of the centrifugal separation device 5 is connected to a water washing storage tank 6 through a pipeline, and the liquid outlet end of the water washing storage tank 6 is connected to a first wastewater station 7 through a pipeline.

[0039] When in use, the waste liquid generated by water washing and centrifugal separation can be fully stirred and homogenized through the water washing storage tank 6 and the first wastewater station 7 and then transported to the first wastewater station 7 for recycling treatment. The centrifugal separation equipment 5 is a centrifuge and the water washing storage tank 6 includes a stirrer.

[0040] For example, Figure 1 As shown, the present invention also includes step 1: adjusting the pH value of waste gas absorption: pumping high-concentration fluorine-containing waste water into the ammonia-containing waste gas absorption device (2) through the fluorine-containing waste liquid delivery pipe (1), and then passing the ammonia-containing waste gas into the fluorine-containing waste water through the ammonia-containing waste gas pipeline (201) for absorption until the pH value of the fluorine-containing waste water is 7-14, and treating the ammonia-containing waste gas by adjusting the pH value. When the pH value is 0-4, the silicon dioxide in the ammonia-containing waste gas can be dissolved, thereby reducing the cleaning frequency of the waste gas tower;

[0041] Step 2: Filtration: Pump the waste liquid with a pH value of 7-14 to the membrane solid-liquid concentration and separation device (3) for filtration treatment;

[0042] Step 3: pH adjustment: pump the waste liquid with a pH value of 7-14 after filtration into the pH adjustment tank (4), and then add high-concentration fluoride-containing wastewater to adjust the pH value to 0-5;

[0043] Step 4: Evaporation and concentration: The waste liquid with a pH value of 0-5 is pumped into the evaporation and concentration equipment (8) for evaporation and concentration treatment, the evaporation temperature is 30-200° C. The condensed water generated during the evaporation process is discharged into the waste liquid transfer tank (9) for collection, and the concentrated liquid generated is collected in the concentrated liquid collection tank;

[0044] Step 5: Crystallization: The concentrated liquid in the collection tank is continuously pumped into the crystallization equipment (11);

[0045] Step 6: Drying: The crystallized material is directly pumped into the centrifuge of the centrifugal separation equipment (5) for centrifugal separation. The solid after centrifugal separation enters the drying equipment (12) through a conveyor belt for drying. The drying temperature is maintained at 60-300° C. and the moisture content after drying is less than 0-5%.

[0046] When in use, by utilizing the combined treatment of fluorine and ammonia, high-concentration fluorine-containing wastewater is subjected to a series of treatments such as waste gas absorption, filtration, pH value adjustment, evaporation concentration, crystallization and drying to prepare ammonium bifluoride products, so that the fluorine-containing wastewater and ammonia waste gas of photovoltaic enterprises can be recycled as resources, replacing the traditional method of adding a large amount of chemicals for flocculation and precipitation treatment, thereby reducing the environmental protection costs of enterprises.

[0047] When the present invention is used, high-concentration fluorine-containing wastewater is first pumped into the ammonia-containing waste gas absorption device 2 through the fluorine-containing waste liquid delivery pipe 1, and then the ammonia-containing waste gas is passed into the fluorine-containing wastewater through the ammonia-containing waste gas pipeline 201 for absorption until the pH value of the fluorine-containing wastewater is 7-14, and then the waste liquid with a pH value of 7-14 is pumped to the membrane solid-liquid concentration and separation device 3 for filtration treatment, and the separated solid silicon dioxide is washed with water, and then centrifuged in the centrifuge of the centrifugal separation device 5 after washing;

[0048] Then the waste liquid with a pH value of 7-14 after filtration is pumped into the pH adjusting tank 4, and then high-concentration fluorine-containing wastewater is added to adjust the pH value to 0-5, and then the waste liquid with a pH value of 0-5 is pumped into the evaporation concentration equipment 8 for evaporation concentration treatment, the evaporation temperature is 30-200°C, and the condensed water generated during the evaporation process is discharged into the waste liquid transfer tank 9 for collection, and the generated concentrated liquid is collected in the concentrated liquid collection barrel;

[0049] Then, the concentrated liquid in the collection barrel is continuously pumped into the crystallization device 11, and the crystallized material is directly pumped into the centrifuge for centrifugal separation. The solid after centrifugal separation enters the drying device 12 through a conveyor belt for drying. The drying temperature is maintained at 60-300°C, and the moisture content after drying is less than 0-5%;

[0050] By using the combined treatment method of high-concentration fluorine-containing wastewater and ammonia-containing waste gas, the high-concentration fluorine-containing wastewater is subjected to a series of treatments such as waste gas absorption, filtration, pH value adjustment, evaporation concentration, crystallization and drying to prepare ammonium bifluoride products. In addition, ammonia-containing waste gas usually contains silica dust. The original front-end treatment can only remove 95% of the dust, which leads to the customer's original waste gas treatment process of using sulfuric acid to absorb ammonia-containing waste gas, which is prone to silica deposition and normally needs to be cleaned once every six months. This process uses hydrofluoric acid waste liquid to absorb ammonia-containing waste gas, which can replace the original waste gas treatment process of absorbing ammonia-containing waste gas with sulfuric acid, dissolve the silica in the ammonia-containing waste gas, reduce the cleaning frequency of the customer's waste gas tower, and enable the photovoltaic enterprise's fluorine-containing wastewater to be recycled as a resource, replacing the traditional method of adding a large amount of reagents for flocculation and precipitation treatment, thereby reducing the company's environmental protection costs.

[0051] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing ammonium bifluoride by combined treatment of fluorine and ammonia in the photovoltaic industry, characterized in that: The invention comprises a fluorine-containing waste liquid conveying pipe (1), an ammonia-containing waste gas absorption device (2), a membrane-type solid-liquid concentration and separation device (3), a pH regulating tank (4), an evaporation and concentration device (8), a crystallization device (11) and a drying device (12), wherein the liquid outlet end of the fluorine-containing waste liquid conveying pipe (1) is connected to the liquid inlet end of the ammonia-containing waste gas absorption device (2), the gas inlet end of the ammonia-containing waste gas absorption device (2) is provided with an ammonia-containing waste gas pipeline (201) for conveying ammonia-containing waste gas, the liquid outlet end of the ammonia-containing waste gas absorption device (2) is connected to the liquid inlet end of the membrane-type solid-liquid concentration and separation device (3), the filtered water discharge end of the membrane-type solid-liquid concentration and separation device (3) is connected to the pH regulating tank (4) through a pipeline, and the waste liquid discharge end of the membrane-type solid-liquid concentration and separation device (3) is connected to the feed end of a centrifugal separation device (5) through a pipeline.

2. The method for preparing ammonium bifluoride by fluorine-ammonia combined treatment in the photovoltaic industry according to claim 1, characterized in that: The liquid outlet of the pH adjustment tank (4) is connected to the evaporation concentration device (8) through a pipeline, the liquid outlet of the evaporation concentration device (8) is connected to the liquid inlet of the crystallization device (11) through a pipeline, and the material outlet of the crystallization device (11) is connected to the drying device (12) through a pipeline.

3. The method for preparing ammonium bifluoride by fluorine-ammonia combined treatment in the photovoltaic industry according to claim 2, characterized in that: The waste liquid outlet of the evaporation concentration device (8) is connected to a waste liquid transfer tank (9) via a pipeline, and the waste liquid outlet of the waste liquid transfer tank (9) is connected to a second wastewater station (10) via a pipeline.

4. The method for preparing ammonium bifluoride by fluorine-ammonia combined treatment in the photovoltaic industry according to claim 3, characterized in that: The evaporation concentration device (8) comprises an evaporator, the crystallization device (11) comprises a crystallizer and a centrifuge, and the liquid outlet of the evaporator is connected to the crystallizer, and the material outlet of the crystallizer is connected to the centrifuge, and the drying device (12) comprises a dryer, and the material outlet of the centrifuge is connected to the material feed end of the dryer through a pipeline, and the liquid outlet of the centrifuge is connected to the waste liquid transfer tank (9).

5. The method for preparing ammonium bifluoride by fluorine-ammonia combined treatment in the photovoltaic industry according to claim 4, characterized in that: The waste liquid outlet of the centrifugal separation device (5) is connected to a water washing storage tank (6) via a pipeline, and the liquid outlet of the water washing storage tank (6) is connected to a first wastewater station (7) via a pipeline.

6. A method for preparing ammonium bifluoride by combined fluorine and ammonia treatment in the photovoltaic industry according to claims 0-5, characterized in that: The specific preparation method is as follows: Step 1: waste gas absorption and pH adjustment: high-concentration fluorine-containing waste water is pumped into the ammonia-containing waste gas absorption device (2) through the fluorine-containing waste liquid delivery pipe (1), and then the ammonia-containing waste gas is introduced into the fluorine-containing waste water through the ammonia-containing waste gas pipeline (201) for absorption until the pH value of the fluorine-containing waste water is 7-14. The ammonia-containing waste gas is treated by adjusting the pH value. When the pH value is between 0 and 4, the silicon dioxide in the ammonia-containing waste gas can be dissolved, thereby reducing the cleaning frequency of the waste gas tower; Step 2: Filtration: Pump the waste liquid with a pH value of 7-14 to the membrane solid-liquid concentration and separation device (3) for filtration treatment; Step 3: pH adjustment: pump the waste liquid with a pH value of 7-14 after filtration into the pH adjustment tank (4), and then add high-concentration fluoride-containing wastewater to adjust the pH value to 0-5; Step 4: Evaporation and concentration: The waste liquid with a pH value of 0-5 is pumped into the evaporation and concentration equipment (8) for evaporation and concentration treatment, the evaporation temperature is 30-200° C. The condensed water generated during the evaporation process is discharged into the waste liquid transfer tank (9) for collection, and the concentrated liquid generated is collected in the concentrated liquid collection tank; Step 5: Crystallization: The concentrated liquid in the collection tank is continuously pumped into the crystallization equipment (11); Step 6: Drying: The crystallized material is directly pumped into the centrifuge of the centrifugal separation equipment (5) for centrifugal separation. The solid after centrifugal separation enters the drying equipment (12) through a conveyor belt for drying. The drying temperature is maintained at 60-300° C. and the moisture content after drying is less than 0-5%.

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