A photovoltaic industry hydrogen fluoride wastewater resource utilization system device and method

Abstract

The present invention discloses a system device and method for resource utilization of hydrogen fluoride wastewater in the photovoltaic industry, which solves the technical problems of low efficiency, high cost and inability to effectively recycle resources in the prior art of hydrogen fluoride wastewater treatment in the photovoltaic industry. The system device for resource utilization of hydrogen fluoride wastewater of the present invention comprises a fluorosilicic acid reaction device, a hydrofluoric acid refining device and a hot steam compression regeneration device. Fluorosilicic acid is precipitated by the fluorosilicic acid reaction device, and the supernatant in the wastewater after centrifugation enters the hydrofluoric acid refining device for hydrofluoric acid refining and recovery. The steam generated by the distillation tower is recycled by the hot steam compression regeneration device, and the precipitated fluorosilicate is reused by cleaning and impurity removal. The system device of the present invention realizes the effective recycling of hydrofluoric acid and fluorosilicic acid at the same time, reduces the amount of wastewater treatment and the amount of water treatment agent used, reduces energy consumption and water treatment costs, and improves work efficiency. It can be widely used in the field of environmental protection technology.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection technology, and in particular to a system device and method for resource utilization of hydrogen fluoride wastewater in the photovoltaic industry. Background Art

[0002] At present, electronic-grade hydrofluoric acid is mainly used in integrated circuits, solar photovoltaics, and liquid crystal displays. The largest application market is the integrated circuit field, accounting for about 47.2% of the total consumption of electronic-grade hydrofluoric acid; followed by the solar photovoltaic field, accounting for 34.5%; and the liquid crystal display field, accounting for 18.3%. In recent years, with the rapid development of China's microelectronics industry, it has gradually become the world's largest liquid crystal display (LCD) industry base. The demand for electronic chemicals used for cleaning and etching agents such as integrated circuits (ICs), thin-film liquid crystal displays (TFT-LCDs) and semiconductors is increasing. The competitiveness of domestic leading enterprises is constantly increasing, and there is huge room for long-term growth.

[0003] The hydrofluoric acid wastewater generated in the photovoltaic and semiconductor industries is highly polluting and destructive to the environment. The current mainstream treatment process is that during the hydrofluoric acid wastewater treatment process, the wastewater passes through the hydrofluoric acid wastewater collection pool in turn, and the wastewater treatment pump enters the pretreatment pool to adjust the pH of the wastewater to 2.4-2.6. The wastewater discharged from the pretreatment pool passes through a multi-media filter to remove suspended matter and organic matter, and then enters the first-order and second-order reverse osmosis systems to remove fluorosilicic acid and fluoride ions in the wastewater, and then the treated wastewater is treated. This treatment process only treats the wastewater, and the effective substances fluorosilicic acid and hydrofluoric acid therein cannot be recycled and reused. In addition, the commonly used chemical precipitation method uses slaked lime to neutralize hydrofluoric acid for precipitation and dehydration process and equipment, which requires a large space, high cost, inconvenient implementation, cumbersome treatment process, and will produce a large amount of sludge. In the end, even after dehydration, there is still a large amount of waste that needs to be treated, which does not conform to the concept of green environmental protection and cannot effectively recycle fluorosilicic acid and hydrofluoric acid.

[0004] The treatment method for hydrogen fluoride-containing wastewater proposed in invention patent CN201910591298.0 "Hydrogen fluoride wastewater treatment production line" involves multi-stage mixing, acid and alkali washing, flocculation tanks, etc., which belongs to the wastewater treatment route and cannot realize the resource utilization of hydrogen fluoride; invention patent CN202111460496.7 "Method and device for preparing hydrogen fluoride from BOE waste liquid" belongs to the resource utilization route, which realizes the resource utilization of hydrogen fluoride through alkali neutralization to form salt, steam stripping to recover ammonia, electrodialysis, distillation and concentration, etc., but the process route is too long, resulting in huge costs for industrial applications, and it is difficult to achieve true resource utilization. Summary of the invention

[0005] In view of the shortcomings and deficiencies in the prior art, the present invention provides a device with reasonable structural design, simple operation, strong practicality, which can realize the effective recovery and utilization of hydrogen fluoride and produce high-quality fluorosilicate products as by-products, thereby alleviating the pressure of wastewater and waste residue treatment at the back end of the photovoltaic production industry, and providing a safe and environmentally friendly photovoltaic industry hydrogen fluoride wastewater resource utilization system device and method.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: The photovoltaic industry hydrogen fluoride wastewater resource utilization system device provided by the present invention is characterized by comprising a fluorosilicic acid reaction device, a hydrofluoric acid refining device and a hot steam compression regeneration device;

[0007] The fluorosilicic acid reaction device uses salt to precipitate fluorosilicic acid in the wastewater; specifically, the fluorosilicic acid reaction device is provided with a first production port at the bottom, and a production pump and a centrifuge are sequentially connected to the side thereof, the production pump suction port and discharge port are respectively connected to the first production port and the centrifuge inlet through pipelines, the centrifuge supernatant outlet is connected to the hydrofluoric acid refining device through a pipeline, and the bottom filter residue outlet is connected to the fluorosilicate refining device through a pipeline;

[0008] The hydrofluoric acid refining device concentrates and recovers the hydrofluoric acid in the wastewater; specifically, the hydrofluoric acid refining device includes a heat exchanger, a distillation tower, a reflux tank, a tower bottom material circulation pump and a reflux pump; the heat exchanger inlet and outlet are respectively connected to the centrifuge supernatant outlet and the lower feed port of the distillation tower through pipelines; the bottom of the distillation tower is connected to the tower bottom material circulation pump through a pipeline, and the liquid after the gas phase at the top of the distillation tower is condensed is refluxed into the distillation tower from the reflux port at the top of the distillation tower through the reflux tank and the reflux pump;

[0009] The hot steam compression regeneration device is used to recycle the steam generated by the distillation tower through the hot steam compression regeneration device.

[0010] Preferably, the hot steam compression regeneration device includes a falling film evaporator at the top of the tower, a gas-liquid separator at the top of the tower, a steam compressor, a falling film evaporator at the bottom of the tower, a gas-liquid separator at the bottom of the tower, a hot water circulation pump at the top of the tower, a superheated steam cooler and a hot water delivery pump at the bottom of the tower;

[0011] The material inlet, material outlet and refrigerant outlet of the falling film evaporator at the top of the tower are respectively connected to the gas outlet at the top of the distillation tower, the inlet of the reflux tank and the gas-liquid separator at the top of the tower through pipelines; the saturated hot water at the bottom of the gas-liquid separator at the top of the tower is connected to the refrigerant inlet of the falling film evaporator at the top of the tower through a pipeline through a hot water circulation pump at the top of the tower, and the internal steam passes through the pipeline through the steam outlet of the gas-liquid separator at the top of the tower, and is processed by the steam compressor and the superheated steam cooler in turn, and then enters the gas-liquid separator at the bottom of the tower;

[0012] The liquid outlet at the bottom of the distillation tower is connected with the falling film evaporator at the bottom of the tower through a pipeline via a bottom material circulation pump, and the material outlet of the falling film evaporator at the bottom of the tower is connected with the gas phase inlet at the lower part of the distillation tower through a pipeline; the steam outlet and inlet of the falling film evaporator at the bottom of the tower are respectively connected with the steam inlet and outlet of the gas-liquid separator at the bottom of the tower through pipelines for circulation; the hot water in the gas-liquid separator at the bottom of the tower is transported to the gas-liquid separator at the top of the tower through a pipeline via a hot water delivery pump.

[0013] Preferably, a liquid collecting tray is further provided in the middle and lower part of the distillation tower, and a side line extraction port of the distillation tower product cooperating with the liquid collecting tray is provided on the side thereof; the waste liquid at the bottom of the distillation tower is discharged through the bottom extraction pump 15.

[0014] Preferably, the fluorosilicic acid reaction device is a closed kettle structure, a tank structure or a trough structure, with a feed inlet and a salt adding inlet provided on the top, and a stirring device provided inside.

[0015] Preferably, the tower top falling film evaporator and the tower bottom falling film evaporator are both vertical impermeable graphite falling film evaporators.

[0016] Preferably, it also includes a fluorosilicic acid refining device, which is used to remove impurities from fluorosilicates after filtration and sedimentation in a centrifuge; specifically, the fluorosilicic acid refining device is sequentially connected with a primary cleaner, a secondary cleaner and a vacuum dryer, the inlet of the primary cleaner is connected to the filter residue outlet of the centrifuge through a pipeline, and the primary cleaner, the secondary cleaner and the vacuum dryer are respectively connected in sequence through pipelines.

[0017] Preferably, the primary cleaning device and the secondary cleaning device are one of an extraction centrifuge, a closed clarification tank or a stirred kettle with a stirring device.

[0018] A method for resource utilization of hydrogen fluoride wastewater in the photovoltaic industry, using any one of the above-mentioned photovoltaic industry hydrogen fluoride wastewater resource utilization system devices, and the specific steps include the following:

[0019] (1) injecting hydrogen fluoride wastewater to be treated into the fluorosilicic acid reaction device;

[0020] (2) Adding a sedimentation agent into the fluosilicic acid reaction device to precipitate the fluosilicic acid in the hydrogen fluoride wastewater;

[0021] (3) the liquid hydrogen fluoride wastewater after the fluorosilicic acid sedimentation in the fluorosilicic acid reaction unit in step (2) is pumped into a centrifuge for centrifugal separation by using a production pump as power;

[0022] (4) pumping the supernatant separated in step (3) into a hydrofluoric acid refining device in batches for refining and recovering the hydrofluoric acid;

[0023] (5) The bottom fluorosilicic acid precipitate separated in step (3) is sent to a fluorosilicic acid refining device for cleaning and impurity removal.

[0024] Preferably, the sedimentation agent added to the fluosilicic acid reaction device is sodium salt or potassium salt, and the sedimentation time is 3h-4h.

[0025] Preferably, the hydrofluoric acid content of the hydrofluoric acid wastewater is 8%-25%, and the fluorosilicic acid content is 0.1%-12%.

[0026] Preferably, in the hydrofluoric acid refining device of step (4), the parameters of the distillation tower are configured as follows: the number of theoretical plates of the hydrofluoric acid distillation tower is 18-52, the product side line extraction position is the 5th to 30th theoretical plate from bottom to top, and the feed position is the 2nd to 10th theoretical plate from bottom to top; the reflux ratio is 3-5:1, and the operating pressure is 60KpaG-101KpaG.

[0027] The present invention has the following beneficial effects:

[0028] (1) The hydrogen fluoride wastewater resource utilization system device of the present invention uses a fluosilicic acid reaction device to precipitate fluosilicic acid, and the fluosilicate after centrifugal precipitation is cleaned and removed by a fluosilicic acid refining device for reuse; the supernatant in the wastewater enters a hydrofluoric acid refining device for hydrofluoric acid refining and recycling, and then the effective components in the hydrogen fluoride wastewater are recycled to achieve resource recovery and improve resource utilization. At the same time, the harmful components in the treated hydrogen fluoride wastewater are greatly reduced, thereby reducing the subsequent treatment procedures of the hydrogen fluoride wastewater. The system device of the present invention simultaneously realizes the effective recycling of hydrofluoric acid and fluosilicic acid in hydrogen fluoride wastewater, reduces the amount of wastewater treatment and the amount of water treatment agent used, reduces energy consumption and water treatment costs, and improves work efficiency.

[0029] (2) In the hydrogen fluoride wastewater resource utilization system of the present invention, the steam generated by the distillation tower passes through a hot steam compression regeneration device, and the heat energy is returned to the hydrofluoric acid refining device for repeated utilization by using the hot steam heat exchange, which greatly reduces production energy consumption and costs, and is in line with the concept of green environmental protection.

[0030] (3) The method for resource utilization of hydrogen fluoride wastewater in the photovoltaic industry of the present invention is simple, easy to implement, and has low operating costs. A precipitant is used to precipitate fluorosilicic acid in the hydrogen fluoride wastewater, so that fluorosilicic acid and hydrofluoric acid can be effectively recycled and utilized, and the harmful components of the hydrogen fluoride wastewater are reduced. The large amount of sludge and waste generated by the use of water treatment agents such as lime and their subsequent treatment steps are avoided, and the wastewater treatment process is simplified while realizing resource regeneration and recycling, effectively improving the economic benefits of the hydrogen fluoride production process and wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of equipment connection of a hydrogen fluoride wastewater resource utilization system of the present invention;

[0032] Figure 2 for Figure 1 Schematic diagram of the equipment connection between the hydrofluoric acid refining unit and the thermal vapor compression regeneration unit.

[0033] In the figure: 1. Fluorosilicic acid reaction device; 101. First production port; 102. Feed port; 103. Salt adding port; 104. Stirring device; 2. Production pump; 3. Centrifuge; 301. Centrifuge cleaning inlet; 4. Heat exchanger; 5. Distillation tower; 501. Product side line production port of distillation tower; 502. Reflux port at the top of distillation tower; 6. Reflux tank; 7. Falling film evaporator at the top of tower; 701. Material inlet of falling film evaporator at the top of tower; 702. Refrigerant inlet of falling film evaporator at the top of tower; 8. Gas-liquid separator at the top of tower; 801. Steam outlet of gas-liquid separator at the top of tower; 9. Steam compressor; 901. Compressor outlet; 10. Falling film evaporator at the bottom of the tower; 1001. Material inlet of falling film evaporator at the bottom of the tower; 11. Gas-liquid separator at the bottom of the tower; 1101. Steam outlet of gas-liquid separator at the bottom of the tower; 12. Hot water circulation pump at the top of the tower; 13. Superheated steam cooler; 1301. Cold water inlet of superheated steam cooler; 14. Material circulation pump at the bottom of the tower; 15. Extraction pump at the bottom of the tower; 16. Reflux pump; 17. Hot water delivery pump at the bottom of the tower; 18. Primary cleaning device; 1801. Washing water inlet of primary cleaning device; 19. Secondary cleaning device; 1901. Washing water inlet of secondary cleaning device; 20. Vacuum dryer; 2001. Heat medium inlet of vacuum dryer. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Example 1

[0036] See also Figure 1-2 , the present invention provides a technical solution:

[0037] The photovoltaic industry hydrogen fluoride wastewater resource utilization system device of the present invention comprises a fluorosilicic acid reaction device, a hydrofluoric acid refining device, a fluorosilicate refining device and a hot steam compression regeneration device. The fluorosilicic acid is precipitated by the fluorosilicic acid reaction device, and the precipitated fluorosilicic acid is cleaned and impurity-removed by the fluorosilicate refining device for reuse; the supernatant in the wastewater enters the hydrofluoric acid refining device for hydrofluoric acid refining and recovery, and the steam generated by the distillation tower is recycled by the hot steam compression regeneration device. The system device of the present invention realizes the effective recycling of hydrofluoric acid and fluorosilicic acid at the same time, reduces the wastewater treatment amount and the use of water treatment agents, reduces energy consumption and wastewater treatment costs, and improves work efficiency.

[0038] The fluorosilicic acid reaction device 1 is a closed kettle structure, with a feed port 102 and a salt addition port 103 on the top, a stirring device 104 for stirring and mixing inside, a first production port 101 on the bottom, and a production pump 2 and a centrifuge 3 on its side in sequence. The suction port and the discharge port of the production pump 2 are connected to the first production port 101 and the inlet of the centrifuge 3 respectively through pipelines, the supernatant outlet of the centrifuge 3 is connected to the hydrofluoric acid refining device through a pipeline, and the filter residue outlet is connected to the fluorosilicate refining device through a pipeline. The centrifuge 3 is also provided with a centrifuge cleaning inlet 301, and the cleaning water entering the centrifuge 3 is the water produced from the top of the distillation tower 5.

[0039] When in use, the hydrogen fluoride wastewater enters the fluorosilicic acid reaction device 1 from the feed port 102, the precipitant sodium salt is added from the salt adding port 103, the stirring device 104 fully stirs the precipitant and the wastewater to mix and react, so that the fluorosilicic acid in the wastewater is precipitated into fluorosilicate precipitate, and the wastewater is centrifuged by the centrifuge 3, and its supernatant enters the hydrofluoric acid refining device, and the fluorosilicate precipitate is cleaned by the centrifuge cleaning inlet 301, and then the fluorosilicic acid precipitate enters the fluorosilicate refining device. By using sodium salt to precipitate fluorosilicic acid, fluorosilicic acid can be effectively recycled and utilized, and at the same time, a large amount of sludge and waste generated by the use of water treatment agents such as lime is reduced, and the cost of water treatment and solid waste treatment is reduced.

[0040] The hydrofluoric acid refining device includes a heat exchanger 4, a distillation tower 5, a reflux tank 6, a bottom material circulation pump 14, a bottom extraction pump 15 and a reflux pump 16; the reflux tank 6, the circulation pump 14, the bottom extraction pump 15 and the reflux pump 16 are located on one side of the distillation tower 5 and are connected to it through pipelines.

[0041] The inlet of the heat exchanger 4 is connected to the supernatant outlet of the centrifuge 3 through a pipeline, and its outlet is connected to the lower feed port of the distillation tower 5 through a pipeline. The bottom of the distillation tower 5 is connected to the bottom material circulation pump 14 through a pipeline; after the gas phase at the top of the distillation tower 5 is condensed, the liquid is refluxed into the distillation tower 5 from the reflux port 502 at the top of the distillation tower through the reflux tank 6 and the reflux pump 16.

[0042] A liquid collecting tray is also provided in the middle and lower part of the distillation tower 5, and a distillation tower product side line outlet 501 is provided on its side to cooperate with the liquid collecting tray; the waste liquid at the bottom of the distillation tower 5 is discharged out of the boundary through the bottom outlet pump 15.

[0043] The supernatant of the hydrogen fluoride wastewater separated by centrifuge 3 is heated by heat exchanger 4 and then enters distillation tower 5 for concentration and separation, and the hydrofluoric acid therein is collected in a liquid collecting tray and then taken out through distillation tower product side line outlet 501, thereby realizing the effective recycling of hydrofluoric acid resources in wastewater and reducing the remaining wastewater treatment procedures and costs.

[0044] The fluorosilicate refining device is sequentially connected with a primary cleaner 18, a secondary cleaner 19 and a vacuum dryer 20, the inlet of the primary cleaner 18 is connected with the filter residue outlet of the centrifuge 3, and the primary cleaner 18, the secondary cleaner 19 and the vacuum dryer 20 are sequentially connected through pipelines.

[0045] The primary washer 18 and the secondary washer 19 are extraction centrifuges, which are respectively provided with a primary washer cleaning water inlet 1801 and a secondary washer cleaning water inlet 1901, and the vacuum dryer 20 is provided with a vacuum dryer heat medium inlet 2001. The fluorosilicate precipitate separated by the centrifuge 3 is successively cleaned by the primary washer 18 and the secondary washer 19 to remove water-soluble impurities, and then enters the vacuum dryer 20 for drying and extraction.

[0046] The hot steam regeneration device includes a tower top falling film evaporator 7, a tower top gas-liquid separator 8, a steam compressor 9, a tower bottom falling film evaporator 10, a tower bottom gas-liquid separator 11, a tower top hot water circulation pump 12, a superheated steam cooler 13 and a tower bottom hot water delivery pump 17.

[0047] The tower top falling film evaporator 7 and the tower bottom falling film evaporator 10 are vertical impermeable graphite falling film evaporators with long service life and strong heat transfer effect.

[0048] The material inlet of the falling film evaporator 7 at the top of the tower is connected with the gas outlet at the top of the distillation tower 5 through a pipeline, its material outlet is connected with the inlet of the reflux tank 6 through a pipeline, and its refrigerant outlet is connected with the gas-liquid separator 8 at the top of the tower through a pipeline; the saturated hot water at the bottom of the gas-liquid separator 8 at the top of the tower is connected with the refrigerant inlet 702 of the falling film evaporator 7 at the top of the tower through a pipeline via the hot water circulation pump 12 at the top of the tower, and its internal steam passes through the steam outlet 801 of the gas-liquid separator at the top of the tower through a pipeline, and is successively heated and pressurized by the steam compressor 9 and cooled by the superheated steam cooler 13 to be treated as saturated steam, and then enters the gas-liquid separator 11 at the bottom of the tower.

[0049] The liquid outlet at the bottom of the distillation tower 5 is connected to the falling film evaporator 10 at the bottom of the tower through a pipeline via a bottom material circulation pump 14, and the material outlet of the falling film evaporator 10 at the bottom of the tower is connected to the gas phase inlet at the lower part of the distillation tower 5 through a pipeline; the steam outlet and inlet of the falling film evaporator 10 at the bottom of the tower are respectively connected to the steam inlet and steam outlet 1101 of the gas-liquid separator 11 at the bottom of the tower through pipelines; the hot water in the gas-liquid separator 11 at the bottom of the tower is transported to the gas-liquid separator 8 at the top of the tower through a pipeline via a hot water delivery pump 17.

[0050] The hot steam regeneration device utilizes the low-pressure saturated hot water in the top gas-liquid separator 8 to exchange heat with the water vapor evaporated from the top of the distillation tower 5 through the top falling film evaporator 7. The low-pressure saturated water vapor generated in the top gas-liquid separator 8 enters the steam compressor 9 for compression and temperature and pressure increase, and then enters the superheated steam cooler 13 from the compressor outlet 901 for cooling, and then enters the bottom falling film evaporator 10 through the bottom gas-liquid separator 11 to exchange heat with the liquid at the bottom of the distillation tower 5. The liquid after heat exchange treatment returns to the distillation tower 5 for reuse, which greatly reduces energy consumption, realizes energy recycling, and is green and environmentally friendly.

[0051] The working principle of this embodiment:

[0052] When in use, the hydrogen fluoride wastewater is injected into the fluorosilicic acid reaction device 1 from the feed port 102, the sodium salt of the precipitant is added from the salt adding port 103, the stirring device 104 is started to fully stir and mix the precipitant and the wastewater, so that the fluorosilicic acid in the wastewater is precipitated into fluorosilicate precipitate, the wastewater after the reaction is completed is centrifuged through the centrifuge 3, and the supernatant enters the hydrofluoric acid refining device. Then, the water extracted from the top of the distillation tower 5 is injected through the centrifuge cleaning inlet 301 to clean the fluorosilicate precipitate obtained by centrifugation, and then the fluorosilicate precipitate enters the fluorosilicate refining device.

[0053] The supernatant of the hydrogen fluoride wastewater separated by centrifuge 3 is heated by heat exchanger 4 and then enters distillation tower 5. By setting the parameters of distillation tower 5, the hydrofluoric acid therein is extracted by distillation and collected in the liquid collecting tray, and then taken out through the distillation tower product side line outlet 501.

[0054] The primary cleaning device 18 and the secondary cleaning device 19 are respectively injected with essence water through the primary cleaning device cleaning water inlet 1801 and the secondary cleaning device cleaning water inlet 1901. The fluorosilicate precipitate separated by the centrifuge 3 is cleaned by the primary cleaning device 18 and the secondary cleaning device 19 in turn, and then enters the vacuum dryer 20 for drying and then collected.

[0055] The hot steam regeneration device utilizes the low-pressure saturated hot water in the top gas-liquid separator 8 to exchange heat with the water vapor evaporated from the top of the distillation tower 5 through the top falling film evaporator 7. The low-pressure saturated water vapor generated in the top gas-liquid separator 8 enters the steam compressor 9 for compression to increase the temperature and pressure, then enters the superheated steam cooler 13 through the compressor outlet 901 to be cooled to saturated steam, then enters the bottom falling film evaporator 10 through the bottom gas-liquid separator 11 to exchange heat with the liquid at the bottom of the distillation tower 5, and the liquid after heat exchange treatment returns to the distillation tower 5 for reuse. Example 2

[0056] The hydrogen fluoride wastewater was treated according to the hydrogen fluoride wastewater resource utilization system device of Example 1, wherein the hydrofluoric acid content of the hydrofluoric acid wastewater was 25%, and the fluorosilicic acid content was 12.1%.

[0057] (1) Inject the hydrogen fluoride wastewater to be treated into the fluorosilicic acid reaction device 1.

[0058] (2) Adding sodium chloride as a sedimentation agent to the fluosilicic acid reaction device 1 to precipitate the fluosilicic acid in the hydrogen fluoride wastewater to generate sodium fluosilicic acid. The amount of sodium chloride added is 2.5 times the content of fluosilicic acid (molar ratio), and the sedimentation time is 3 hours.

[0059] (3) Step (2) After the fluorosilicic acid is settled in the fluorosilicic acid reaction device 1, the extraction pump 2 provides power to allow the hydrogen fluoride wastewater to enter the centrifuge 3 for centrifugal separation.

[0060] (4) The supernatant separated in step (3) is fed into a hydrofluoric acid refining device in batches for hydrofluoric acid refining and recovery. The number of theoretical plates of the hydrofluoric acid distillation tower is 52, the product side line extraction position is the 30th theoretical plate from bottom to top, the feed position is the 5th theoretical plate from bottom to top, the reflux ratio is 4:1, the operating pressure is 101 KPaG, the tower top temperature is 105°C, the tower bottom temperature is 117°C, and the reflux temperature is 93°C.

[0061] (5) The fluorosilicic acid precipitate separated in step (3) is placed in a fluorosilicate refining device for cleaning and impurity removal.

[0062] The purity of the recovered hydrofluoric acid was 31.6 wt%, of which hydrogen chloride was 0.24%, and the recovery rate was 93.3%; the purity of the recovered sodium fluorosilicate was 99.2 wt%, and the recovery rate of fluorosilicic acid was 95.8%. Example 3

[0063] The hydrogen fluoride wastewater was treated according to the hydrogen fluoride wastewater resource utilization system device of Example 1, wherein the hydrofluoric acid content of the hydrofluoric acid wastewater was 12.7%, and the fluorosilicic acid content was 5.2%.

[0064] (1) Inject the hydrogen fluoride wastewater to be treated into the fluorosilicic acid reaction device 1.

[0065] (2) Adding a precipitant sodium sulfate into the fluorosilicic acid reaction device 1 to precipitate the fluorosilicic acid in the hydrogen fluoride wastewater to generate sodium fluorosilicate. The amount of sodium sulfate added is 1.2 times the content of fluorosilicic acid (molar ratio), and the precipitation time is 4 hours.

[0066] (3) Step (2) After the fluorosilicic acid is settled in the fluorosilicic acid reaction device 1, the extraction pump 2 provides power to allow the hydrogen fluoride wastewater to enter the centrifuge 3 for centrifugal separation.

[0067] (4) The supernatant separated in step (3) is fed into a hydrofluoric acid refining device in batches for hydrofluoric acid refining and recovery. The hydrofluoric acid distillation tower has 40 theoretical plates, the product side line extraction position is the 25th theoretical plate from bottom to top, the feed position is the 5th theoretical plate from bottom to top, the reflux ratio is 2:1, the operating pressure is 101 KPaG, the tower top temperature is 104°C, the tower bottom temperature is 119°C, and the reflux temperature is 95°C.

[0068] (5) The fluorosilicic acid precipitate separated in step (3) is placed in a fluorosilicate refining device for cleaning and impurity removal.

[0069] The purity of the recovered hydrofluoric acid was 22.6wt%, of which the sulfuric acid content was 0.07%, and the recovery rate was 95.3%; the purity of the recovered sodium fluorosilicate was 98.6%, and the recovery rate was 86.2%. Example 4

[0070] The hydrogen fluoride wastewater was treated according to the hydrogen fluoride wastewater resource utilization system device of Example 1, wherein the hydrofluoric acid content of the hydrofluoric acid wastewater was 8%, and the fluorosilicic acid content was 0.1%.

[0071] (1) Inject the hydrogen fluoride wastewater to be treated into the fluorosilicic acid reaction device 1.

[0072] (2) Potassium chloride as a precipitant is added to the fluorosilicic acid reaction device 1 to precipitate the fluorosilicic acid in the hydrogen fluoride wastewater to generate potassium fluorosilicate precipitate. The amount of potassium chloride added is 2.1 times the content of fluorosilicic acid (molar ratio), and the precipitation time is 3 hours.

[0073] (3) Step (2) After the fluorosilicic acid is settled in the fluorosilicic acid reaction device 1, the extraction pump 2 provides power to allow the hydrogen fluoride wastewater to enter the centrifuge 3 for centrifugal separation.

[0074] (4) The supernatant separated in step (3) is fed into a hydrofluoric acid refining device in batches for hydrofluoric acid refining and recovery. The number of theoretical plates of the hydrofluoric acid distillation tower is 30, the product side line extraction position is the 22nd theoretical plate from bottom to top, the feed position is the 5th theoretical plate from bottom to top, the reflux ratio is 3:1, the operating pressure is 101 KPaG, the tower top temperature is 102°C, the tower bottom temperature is 115°C, and the reflux temperature is 88°C.

[0075] (5) The fluorosilicic acid precipitate separated in step (3) is placed in a fluorosilicate refining device for cleaning and impurity removal.

[0076] The purity of the recovered hydrofluoric acid was 18.6wt%, of which hydrogen chloride was 0.05wt%, and the recovery rate was 91.5%; the purity of the recovered potassium fluorosilicate was 98.4wt%, and the recovery rate was 85.4%. Example 5

[0077] The hydrogen fluoride wastewater was treated according to the hydrogen fluoride wastewater resource utilization system device of Example 1, wherein the hydrofluoric acid content of the hydrofluoric acid wastewater was 21%, and the fluorosilicic acid content was 6.3%.

[0078] (1) Inject the hydrogen fluoride wastewater to be treated into the fluorosilicic acid reaction device 1.

[0079] (2) Potassium fluoride as a sedimentation agent is added to the fluosilicic acid reaction device 1 to precipitate the fluosilicic acid in the hydrogen fluoride wastewater to generate potassium fluosilicate. The amount of potassium fluoride added is 2.3 times the content of fluosilicic acid (molar ratio), and the sedimentation time is 4 hours.

[0080] (3) Step (2) After the fluorosilicic acid is settled in the fluorosilicic acid reaction device 1, the extraction pump 2 provides power to allow the hydrogen fluoride wastewater to enter the centrifuge 3 for centrifugal separation.

[0081] (4) The supernatant separated in step (3) is fed into a hydrofluoric acid refining device in batches for hydrofluoric acid refining and recovery. The hydrofluoric acid distillation tower has 18 theoretical plates, the product side line extraction position is the 13th theoretical plate from bottom to top, the feed position is the 3rd theoretical plate from bottom to top, the reflux ratio is 5:1, the operating pressure is 60 KPaG, the tower top temperature is 81.3°C, the tower bottom temperature is 90.8°C, and the reflux temperature is 71.6°C.

[0082] (5) The fluorosilicic acid precipitate separated in step (3) is placed in a fluorosilicate refining device for cleaning and impurity removal.

[0083] The purity of the recovered hydrofluoric acid was 27.6wt% (no other acids were detected), and the recovery rate was 96.3%; the purity of the recovered potassium fluorosilicate was 99.1wt%, and the recovery rate was 96.3%. Example 6

[0084] The hydrogen fluoride wastewater was treated according to the hydrogen fluoride wastewater resource utilization system device of Example 1, wherein the hydrofluoric acid content of the hydrofluoric acid wastewater was 25%, and the fluorosilicic acid content was 12.1%.

[0085] (1) Inject the hydrogen fluoride wastewater to be treated into the fluorosilicic acid reaction device 1.

[0086] (2) Add sodium chloride as a sedimentation agent to the fluosilicic acid reaction device 1 to precipitate the fluosilicic acid and sodium fluosilicate in the hydrogen fluoride wastewater. The amount of sodium chloride added is 2.5 times the content of fluosilicic acid (molar ratio), and the sedimentation time is 4 hours.

[0087] (3) Step (2) After the fluorosilicic acid is settled in the fluorosilicic acid reaction device 1, the extraction pump 2 provides power to allow the hydrogen fluoride wastewater to enter the centrifuge 3 for centrifugal separation.

[0088] (4) The supernatant separated in step (3) is fed into a hydrofluoric acid refining device in batches for hydrofluoric acid refining and recovery. The hydrofluoric acid distillation tower has 44 theoretical plates, the product side line extraction position is the 30th theoretical plate from bottom to top, the feed position is the 10th theoretical plate from bottom to top, the reflux ratio is 4:1, the operating pressure is 80 KPaG, the tower top temperature is 93.7°C, the tower bottom temperature is 103.6°C, and the reflux temperature is 87.3°C.

[0089] (5) The fluorosilicic acid precipitate separated in step (3) is placed in a fluorosilicate refining device for cleaning and impurity removal.

[0090] The purity of the recovered hydrofluoric acid was 31.3 wt %, of which hydrogen chloride was 0.11 %, and the recovery rate was 95.3 %; the purity of the recovered sodium fluorosilicate was 99.3 %, and the recovery rate was 91.8 %.

[0091] In summary, the photovoltaic industry hydrogen fluoride wastewater resource utilization system device and method of the present invention, fluorosilicic acid is precipitated through a fluorosilicic acid reaction device, and the precipitated fluorosilicic acid is cleaned and impurity-removed by a fluorosilicate refining device for reuse; the supernatant in the wastewater enters a hydrofluoric acid refining device for hydrofluoric acid refining and recovery, and the steam generated by the distillation tower is recycled by a hot steam compression regeneration device. The system device of the present invention simultaneously realizes the effective recycling of hydrofluoric acid and fluorosilicic acid, reduces the amount of wastewater treated and the amount of water treatment agent used, reduces energy consumption and water treatment costs, improves work efficiency, and has a wide range of applications.

[0092] The above are only preferred specific embodiments of the present invention. For example, the types of the cleaning device and falling film evaporator used in the embodiments can be optimized according to different situations in actual applications. The selection of the precipitating agent of the present invention includes but is not limited to sodium chloride, sodium sulfate, sodium fluoride, potassium chloride, potassium sulfate and potassium fluoride. If the product index has strict requirements on the regeneration of hydrofluoric acid chloride ions and sulfate radicals, sodium fluoride and potassium fluoride are preferably used as the precipitating agent.

[0093] The above description is only a preferred specific implementation manner of the present invention, and the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A photovoltaic industry hydrogen fluoride wastewater resource utilization system device, characterized in that: It includes a fluorosilicic acid reaction device, a hydrofluoric acid refining device and a hot steam compression regeneration device; The fluorosilicic acid reaction device uses salt to precipitate fluorosilicic acid in wastewater; the fluorosilicic acid reaction device (1) is provided with a first production port (101) at the bottom, and a production pump (2) and a centrifuge (3) are sequentially connected to the side thereof; the suction port and the discharge port of the production pump (2) are respectively connected to the first production port (101) and the inlet of the centrifuge (3) through pipelines; the supernatant outlet of the centrifuge (3) is connected to the hydrofluoric acid refining device through a pipeline; and the filter residue outlet at the bottom is connected to the fluorosilicate refining device through a pipeline; The hydrofluoric acid refining device concentrates and recovers the hydrofluoric acid in the wastewater; the hydrofluoric acid refining device comprises a heat exchanger (4), a distillation tower (5), a reflux tank (6), a tower bottom material circulation pump (14) and a reflux pump (16); the inlet and outlet of the heat exchanger (4) are respectively connected to the supernatant outlet of the centrifuge (3) and the lower feed port of the distillation tower (5) through pipelines; the bottom of the distillation tower (5) is connected to the tower bottom material circulation pump (14) through a pipeline, and the liquid after the gas phase at the top of the distillation tower (5) is condensed passes through the reflux tank (6) and the reflux pump (16) and flows back into the distillation tower (5) from the reflux port (502) at the top of the distillation tower; The hot steam compression regeneration device is used to recycle the steam generated by the distillation tower (5) through the hot steam compression regeneration device; The hot steam compression regeneration device comprises a tower top falling film evaporator (7), a tower top gas-liquid separator (8), a steam compressor (9), a tower bottom falling film evaporator (10), a tower bottom gas-liquid separator (11), a tower top hot water circulation pump (12), a superheated steam cooler (13) and a tower bottom hot water delivery pump (17); The material inlet, material outlet and refrigerant outlet of the falling film evaporator (7) at the top of the tower are respectively connected to the gas outlet at the top of the distillation tower (5), the inlet of the reflux tank (6) and the gas-liquid separator (8) at the top of the tower through pipelines; the saturated hot water at the bottom of the gas-liquid separator (8) at the top of the tower is connected to the refrigerant inlet (702) of the falling film evaporator at the top of the tower through pipelines via the hot water circulation pump (12) at the top of the tower, and the internal steam passes through the pipeline through the steam outlet (801) of the gas-liquid separator at the top of the tower, and is processed by the steam compressor (9) and the superheated steam cooler (13) in turn, and then enters the gas-liquid separator (11) at the bottom of the tower; The liquid outlet at the bottom of the distillation tower (5) is connected to the falling film evaporator (10) at the bottom of the tower through a pipeline via the material circulation pump (14) at the bottom of the tower, and the material outlet of the falling film evaporator (10) at the bottom of the tower is connected to the gas phase inlet at the lower part of the distillation tower (5) through a pipeline; the steam outlet and inlet of the falling film evaporator (10) at the bottom of the tower are respectively connected to the steam inlet and outlet of the gas-liquid separator (11) at the bottom of the tower through pipelines; the hot water in the gas-liquid separator (11) at the bottom of the tower is transported to the gas-liquid separator (8) at the top of the tower through a pipeline via a hot water transport pump (17); The invention also comprises a fluorosilicate refining device, which is used to remove impurities from the fluorosilicate after filtering and settling in the centrifuge (3); the fluorosilicate refining device is sequentially connected to a primary cleaner (18), a secondary cleaner (19) and a vacuum dryer (20); the inlet of the primary cleaner (18) is connected to the filter residue outlet of the centrifuge (3) through a pipeline, and the primary cleaner (18), the secondary cleaner (19) and the vacuum dryer (20) are sequentially connected through pipelines.

2. A photovoltaic industry hydrogen fluoride wastewater resource utilization system device according to claim 1, characterized in that: A liquid collecting tray is also provided in the inner and lower part of the distillation tower (5), and a distillation tower product side line extraction port (501) is provided on the side thereof to cooperate with the liquid collecting tray; waste liquid at the bottom of the distillation tower (5) is discharged through a bottom extraction pump (15).

3. A photovoltaic industry hydrogen fluoride wastewater resource utilization system device according to claim 1, characterized in that: The fluorosilicic acid reaction device (1) is a closed kettle structure, a tank structure or a trough structure, with a feed inlet (102) and a salt addition inlet (103) provided on the top, and a stirring device (104) provided inside.

4. A photovoltaic industry hydrogen fluoride wastewater resource utilization system device according to claim 1, characterized in that: The tower top falling film evaporator (7) and the tower bottom falling film evaporator (10) are both vertical impermeable graphite falling film evaporators.

5. A photovoltaic industry hydrogen fluoride wastewater resource utilization system device according to claim 1, characterized in that: The primary cleaning device (18) and the secondary cleaning device (19) are one of an extraction centrifuge, a closed clarification tank, or a stirring kettle with a stirring device.

6. A method for resource utilization of hydrogen fluoride wastewater in the photovoltaic industry, characterized by: Using the photovoltaic industry hydrogen fluoride wastewater resource utilization system device according to any one of claims 1 to 5, the specific steps include the following: (1) injecting the hydrogen fluoride wastewater to be treated into the fluorosilicic acid reaction device (1); (2) adding a precipitant to the fluorosilicic acid reaction device (1) to precipitate the fluorosilicic acid in the hydrogen fluoride wastewater; (3) the extraction pump (2) provides power to move the liquid hydrogen fluoride wastewater after the fluorosilicic acid precipitation in the fluorosilicic acid reaction device (1) in step (2) into the centrifuge (3) for centrifugal separation; (4) the supernatant separated in step (3) is fed into the hydrofluoric acid refining device in batches for refining and recovering the hydrofluoric acid; (5) The bottom fluorosilicic acid precipitate separated in step (3) is sent to the fluorosilicate refining device for cleaning and impurity removal.

7. A method for resource utilization of hydrogen fluoride wastewater in the photovoltaic industry according to claim 6, characterized in that: The sedimentation agent added to the fluosilicic acid reaction device (1) is sodium salt or potassium salt, and the sedimentation time is 3h-4h.

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