Recycling defluorination crystallization device

Abstract

The utility model relates to the technical field of wastewater treatment, in particular to a recycling defluorination crystallization device, which comprises a reaction tank body, a water outlet area, a settling area, a water inlet area, a mixing area, a stirring component, a first-stage reaction area and a second-stage reaction area. The method is suitable for all medium-high-concentration fluorine-containing wastewater, the effluent quality is excellent, the fluoride concentration can be lower than 1mg / L at the minimum, fluorine resources of incoming water can be fully utilized, waste is turned into wealth, fluorine-containing sludge is not generated, economic benefits can be generated, and the problems that a traditional fluorine removal process is large in agent dosage, large in sludge yield, and whether the sludge is hazardous waste or not needs to be identified are solved; and the process has the advantages of small agent dosage, high facility integration level, small occupied area, reduction of the operation cost of a sewage plant and simplicity in operation and maintenance, not only solves the problem of fluorine pollution of the fluorine-containing wastewater, but also can solve the problem of fluorinated sludge treatment, and has certain popularization value.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, specifically a resource-based defluorination crystallization device. Background Technology

[0002] Currently, there are many methods for defluoridation of groundwater both domestically and internationally, mainly including: chemical precipitation, adsorption, coagulation sedimentation, ion exchange, electrocoagulation, and reverse osmosis.

[0003] While reverse osmosis, ion exchange, and electrodialysis offer high fluoride removal rates in water, their high treatment costs limit their application in my country. Common fluoride removal methods include chemical precipitation and adsorption. Adsorption is widely used in drinking water treatment due to its low operational requirements and simple implementation; however, its long adsorption time, high operating costs, and safety concerns make it unsuitable for widespread adoption in rural areas of China. In contrast, precipitating fluoride ions from water using calcium salts and defluorinating agents offers lower costs, but its effectiveness is easily affected by operational factors such as stirring conditions, settling time, pH value, and the concentration of anions like sulfate in the water. This results in unstable effluent quality, generates large amounts of sludge that are difficult to dewater, and underutilizes the resources in the wastewater. With increasingly stringent environmental regulations and a growing scarcity of landfill permits, the resource recovery technology for fluoride-containing wastewater shows great promise. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a resource-based defluorination crystallization device, thereby resolving the problems mentioned in the background section.

[0005] The technical solution adopted by this utility model to solve its technical problem is a resource-based defluorination crystallization device, including a reaction tank body. The reaction tank body is an integrated barrel-shaped structure, with an outlet water zone and a sedimentation zone respectively arranged at both ends. Inside the reaction tank body, from the sedimentation zone to the outlet water zone, an inlet water zone, a mixing zone and a primary reaction zone are arranged in sequence. A baffle is arranged between the primary reaction zone and the reaction tank body, and a secondary reaction zone is formed between the two sides of the baffle and the primary reaction zone and the reaction tank body respectively.

[0006] The water outlet area includes a water outlet chamber fixedly connected to the upper surface of the reaction tank body. An overflow weir is fixedly installed inside the water outlet chamber. Several through holes connected to the secondary reaction zone are evenly opened inside the overflow weir in the water outlet chamber. A first water outlet hole and a second water outlet hole are respectively opened on both sides of the lower surface of the water outlet chamber. A water outlet pipe is fixedly connected to the first water outlet hole. A circulating water pump is set below the second water outlet hole. The upper surface of the circulating water pump is fixedly connected to the lower surface of the water outlet chamber. The water inlet of the circulating water pump is connected to the second water outlet hole. A return pipe is fixedly connected to the water outlet of the circulating water pump.

[0007] The precipitation zone includes a conical precipitation chamber fixedly connected to the lower surface of the reaction vessel body. A crystal discharge pipe is fixedly connected to the lower surface of the conical precipitation chamber, and the crystal discharge pipe is controlled by a valve.

[0008] The primary reaction zone includes multiple connecting plates fixedly connected to the lower surface of the effluent chamber. A primary reaction tank with a conical bottom is fixedly connected to the lower surface of the connecting plates. The interior of the primary reaction tank is a cavity for the reaction of wastewater and reagents. A flow channel is formed between two adjacent connecting plates.

[0009] The mixing zone includes a mixing pipe that is fixedly connected to the lower surface of the primary reaction vessel, and the inner cavity of the mixing pipe is welded with several stainless steel plates.

[0010] The water inlet area includes a conical water inlet chamber that is fixedly connected to the lower surface of the mixing pipe. The lower surface of the water inlet chamber is fixedly connected to a water inlet pipe, a seed crystal dosing pipe, a first reagent dosing pipe, and a second reagent dosing pipe.

[0011] A stirring assembly is also provided inside the primary and secondary reaction zones. The stirring assembly includes a drive shaft that passes through and is rotatably connected to the outlet chamber and multiple driven shafts. One end of the drive shaft extends into the interior of the primary reaction zone and the other end extends into the exterior of the outlet chamber. One end of each driven shaft extends into the interior of the secondary reaction zone and the other end extends into the exterior of the outlet chamber. Several stirring blades are fixedly connected to the drive shaft and the multiple driven shafts located inside the primary and secondary reaction zones, respectively. The drive shaft is driven by a pulley assembly, and the two adjacent driven shafts are driven by a pulley assembly.

[0012] Preferably, the water inlet pipe, seed crystal dosing pipe, first reagent dosing pipe, and second reagent dosing pipe all penetrate the sedimentation tank and extend to its exterior.

[0013] Preferably, the end of the return pipe away from the circulating water pump passes through the sedimentation tank and is fixedly connected to the inlet tank.

[0014] Preferably, a support plate is fixedly connected to the upper surface of the water outlet chamber, and a motor is fixedly connected to the upper surface of the support plate. The output end of the motor is fixedly connected to one end of the drive shaft located outside the water outlet chamber.

[0015] Preferably, the first and second reagent dosing tubes can be selected with different reagents and seed crystals according to different effluent water quality requirements. The effluent fluoride concentration is required to be less than or equal to 8 mg / L, and fluorite seed crystals and calcium chloride and calcium hydroxide reagents are used.

[0016] The effluent fluoride concentration should be less than or equal to 1 mg / L. Fluoroapatite seed crystals are used, and phosphate and calcium chloride reagents are employed.

[0017] Preferably, the concentration of the seed crystals added by the seed crystal adding tube is not less than 8 g / L.

[0018] The beneficial effects of this utility model are:

[0019] Compared with two-stage calcium salt precipitation or defluoridation chemical processes, this invention has a wider range of applications, suitable for all medium-to-high concentration fluoride-containing wastewater, and produces high-quality effluent with a fluoride concentration as low as 1 mg / L. It fully utilizes the fluoride resources of the incoming water, turning waste into treasure, and does not produce fluoride-containing sludge, thus generating economic benefits. It differs from traditional defluoridation processes in that it requires large amounts of chemicals, produces large amounts of sludge, and requires sludge identification to determine if the sludge is hazardous waste. Furthermore, this process requires less chemicals, has high facility integration, occupies less land, reduces wastewater treatment plant operating costs, and simplifies operation and maintenance. It not only solves the fluoride pollution problem of fluoride-containing wastewater but also addresses the disposal of fluoride sludge, making it worthy of widespread application. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the internal structure of the reaction vessel body of this utility model;

[0023] Figure 3 This is a schematic diagram of the mixing zone structure of this utility model;

[0024] Figure 4 This is a partial structural schematic diagram of the present invention;

[0025] Figure 5 This is a schematic diagram of the water outlet area structure of this utility model;

[0026] Figure 6 This is a diagram showing the fluoride concentration in the influent of this utility model.

[0027] Figure 7 This is a diagram showing the fluoride concentration in the effluent from the present invention.

[0028] In the picture:

[0029] 1. Reactor body; 101. Secondary reaction zone; 2. Water outlet zone; 201. Water outlet chamber; 202. Overflow weir; 203. Through hole; 204. First water outlet hole; 205. Second water outlet hole; 206. Water outlet pipe; 207. Circulating water pump; 208. Return pipe; 3. Sedimentation zone; 301. Conical sedimentation chamber; 302. Crystal discharge pipe; 4. Water inlet zone; 401. Conical water inlet chamber; 402. Water inlet pipe; 403. Seed crystal addition pipe; 404. First reagent addition pipe; 405. Second reagent addition pipe; 5. Mixing zone; 501. Mixing pipe; 502. Stainless steel plate; 6. Primary reaction zone; 601. Connecting plate; 602. Primary reaction tank; 7. Stirring assembly; 701. Drive shaft; 702. Driven shaft; 703. Stirring blades; 8. Support plate; 801. Motor. Detailed Implementation

[0030] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0031] like Figures 1 to 7 As shown, a preferred embodiment of this utility model proposes a resource-based defluorination crystallization device, including a reaction tank body 1. The reaction tank body 1 is an integral barrel-shaped structure, with an outlet water zone 2 and a sedimentation zone 3 respectively provided at both ends. Inside the reaction tank body 1, from the sedimentation zone 3 to the outlet water zone 2, an inlet water zone 4, a mixing zone 5 and a primary reaction zone 6 are arranged in sequence. A baffle is provided between the primary reaction zone 6 and the reaction tank body 1, and the two sides of the baffle form a secondary reaction zone 101 between the primary reaction zone 6 and the reaction tank body 1 respectively.

[0032] The water outlet zone 2 includes a water outlet chamber 201 fixedly connected to the upper surface of the reaction tank body 1. An overflow weir 202 is fixedly installed inside the water outlet chamber 201. Several through holes 203 connected to the secondary reaction zone 101 are evenly opened inside the overflow weir 202. A first water outlet hole 204 and a second water outlet hole 205 are respectively opened on both sides of the lower surface of the water outlet chamber 201. A water outlet pipe 206 is fixedly connected to the first water outlet hole 204. A circulating water pump 207 is set below the second water outlet hole 205. The upper surface of the circulating water pump 207 is fixedly connected to the lower surface of the water outlet chamber 201. The water inlet of the circulating water pump 207 is connected to the second water outlet hole 205. The water outlet of the circulating water pump 207 is fixedly connected to the return pipe 208.

[0033] Among them, the end of the return pipe 208 away from the circulating water pump 207 passes through the sedimentation tank and is fixedly connected to the inlet tank;

[0034] The sedimentation zone 3 includes a conical sedimentation chamber 301 fixedly connected to the lower surface of the reaction vessel body 1. A crystal discharge pipe 302 is fixedly connected to the lower surface of the conical sedimentation chamber 301, and the crystal discharge pipe 302 is controlled by a valve.

[0035] The primary reaction zone 6 includes multiple connecting plates 601 fixedly connected to the lower surface of the effluent chamber 201. A primary reaction tank 602 with a conical bottom is fixedly connected to the lower surface of the connecting plates 601. The primary reaction tank 602 has a cavity inside for the reaction of sewage and reagents. A flow channel is formed between two adjacent connecting plates 601.

[0036] Mixing zone 5 includes a mixing pipe 501 that is fixedly connected to the lower surface of primary reaction vessel 602. Several stainless steel plates 502 are welded into the inner cavity of mixing pipe 501.

[0037] The water inlet zone 4 includes a conical water inlet chamber 401 that is fixedly connected to the lower surface of the mixing pipe 501. The lower surface of the water inlet chamber is fixedly connected to a water inlet pipe 402, a seed crystal dosing pipe 403, a first reagent dosing pipe 404, and a second reagent dosing pipe 405.

[0038] Among them, the water inlet pipe 402, the seed crystal addition pipe 403, the first reagent addition pipe 404, and the second reagent addition pipe 405 all penetrate the sedimentation tank and extend to its outside;

[0039] A stirring assembly 7 is also provided inside the primary reaction zone 6 and the secondary reaction zone 101. The stirring assembly 7 includes a drive shaft 701 that passes through the water outlet chamber 201 and is rotatably connected to it, and multiple driven shafts 702. One end of the drive shaft 701 extends into the interior of the primary reaction zone 6 and the other end extends into the exterior of the water outlet chamber 201. One end of the driven shaft 702 extends into the interior of the secondary reaction zone 101 and the other end extends into the exterior of the water outlet chamber 201. Several stirring blades 703 are fixedly connected to the inner parts of the drive shaft 701 and the multiple driven shafts 702 respectively in the primary reaction zone 6 and the secondary reaction zone 101. The drive shaft 701 and two adjacent driven shafts 702 are driven by a pulley assembly, and the two adjacent driven shafts 702 are driven by a pulley assembly.

[0040] A support plate 8 is fixedly connected to the upper surface of the water outlet chamber 201, and a motor 801 is fixedly connected to the upper surface of the support plate 8. The output end of the motor 801 is fixedly connected to one end of the drive shaft 701 located outside the water outlet chamber 201.

[0041] During operation, wastewater continuously flows from the inlet pipe 402 into the conical inlet chamber 401, where it mixes with the reagents (calcium chloride and calcium hydroxide or phosphate and calcium chloride) and seed crystals (fluorite or fluorapatite) added by the first reagent dosing pipe 404, the second reagent dosing pipe 405, and the seed crystal dosing pipe 403. The mixture then flows through the mixing pipe 501 into the primary reaction tank 602. The mixing pipe 501 has multiple staggered stainless steel plates welded inside. The wastewater, reagents, and seed crystals react and mix thoroughly as they flow from the mixing pipe 501 to the primary reaction tank 602. At this point, the motor 801 can be turned on. The output of the motor 801 drives the drive shaft 701 to rotate. The drive shaft 701 drives the driven shaft 702 to rotate via a pulley assembly. The driven shaft 702 then drives the stirring blades 703 to rotate, thereby stirring the mixture in the primary reaction tank 602 and ensuring more thorough mixing. In the primary reaction tank 602, fluoride reacts with reagents to generate calcium fluoride or calcium fluorophosphate. The water flows out through the channel formed between two adjacent connecting plates 601 and enters the secondary reaction zone 101. In the secondary reaction zone 101, calcium fluoride or calcium fluorophosphate adheres to the crystal surface through heterogeneous nucleation of crystal seeds. Under the action of gravity, mud and water are separated, and the crystals sink into the conical sedimentation zone 301. The crystal discharge pipe 302 is controlled by a valve to periodically discharge the crystals for resource utilization and maintain the crystal concentration in the reactor. The fluoride concentration of the supernatant effluent is ≤1mg / L. It flows into the effluent chamber 201 through the through hole 203, and then through the overflow weir 202 and the first effluent hole 204 until it is discharged through the effluent pipe 14 in compliance with the standard. Part of the supernatant flows back to the conical inlet chamber 401 through the second effluent hole 205 via the circulation pump 207 and the return pipe 208 to maintain the seed fluidization state.

[0042] Furthermore, the first reagent dosing pipe 404 and the second reagent dosing pipe 405 can be selected with different reagents and seed crystals according to different effluent water quality requirements. The effluent fluoride concentration is required to be less than or equal to 8 mg / L, and fluorite seed crystals and calcium chloride and calcium hydroxide reagents are used.

[0043] The effluent fluoride concentration is required to be less than or equal to 1 mg / L. Fluoroapatite seed crystals are used, and phosphate and calcium chloride reagents are employed. It has a wide range of applications and is suitable for different scenarios.

[0044] Furthermore, the concentration of the seed crystals added through the seed crystal addition tube 403 is not less than 8 g / L, and they need to be discharged periodically to maintain the seed crystal concentration in the reactor. The seed crystals can also be returned to the facility for reuse.

[0045] For example, a photovoltaic energy company's wastewater treatment plant in a certain city has a fluoride-containing wastewater treatment capacity of 10,000 m³ / d. The original design used a two-stage calcium salt precipitation method for fluoride removal, which resulted in large sludge production with no disposal outlet, high reagent dosage, and high operating costs. In September 2024, a high-efficiency fluoride resource utilization facility was adopted to treat the fluoride-containing wastewater. Considering that the company's effluent was discharged into a downstream wastewater treatment plant for further treatment, and the fluoride concentration in the effluent was insufficient, the project used fluorite as a seed crystal and calcium hydroxide and calcium chloride as defluorination agents. After a period of operation, the influent and effluent water quality improved significantly. Figure 6 and Figure 7 As shown:

[0046] The energy consumption during operation is compared in the table below:

[0047] As shown in the influent and effluent fluoride concentration charts, the average influent fluoride concentration of the project is approximately 600 mg / L. After using this facility for defluorination, the minimum fluoride concentration can be reduced to 6 mg / L. Considering that the enterprise's effluent requirements are not high, the average effluent fluoride concentration of the facility is 15 mg / L, and the effluent quality meets the requirements. As shown in Table 1, by comparing the operating costs of the original process in the plant with the operating costs of this facility, the operating cost of this facility is lower, saving 1.83 yuan in operating costs per ton of water treated, which has high economic benefits.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The descriptions of the above embodiments and specifications are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by this utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A resource-based defluorination crystallization device, comprising a reaction vessel body (1), characterized in that: The reaction tank body (1) is an integral barrel structure with an outlet area (2) and a sedimentation area (3) at its two ends respectively. Inside the reaction tank body (1), from the sedimentation area (3) to the outlet area (2), there are an inlet area (4), a mixing area (5) and a primary reaction area (6) in sequence. A baffle is provided between the primary reaction area (6) and the reaction tank body (1). The two sides of the baffle form a secondary reaction area (101) between the primary reaction area (6) and the reaction tank body (1) respectively.

2. The resource-based defluorination crystallization device according to claim 1, characterized in that: The water outlet area (2) includes a water outlet chamber (201) fixedly connected to the upper surface of the reaction tank body (1). An overflow weir (202) is fixedly installed in the inner cavity of the water outlet chamber (201). The water outlet chamber (201) is provided with a number of through holes (203) that are connected to the secondary reaction zone (101) evenly on the inner side of the overflow weir (202). A first water outlet hole (204) and a second water outlet hole (205) are respectively provided on both sides of the lower surface of the water outlet chamber (201). The first water outlet hole (204) is fixedly connected to a water outlet pipe (206). A circulating water pump (207) is provided below the second water outlet hole (205). The upper surface of the circulating water pump (207) is fixedly connected to the lower surface of the water outlet chamber (201). The water inlet end of the circulating water pump (207) is connected to the second water outlet hole (205). The water outlet end of the circulating water pump (207) is fixedly connected to a return pipe (208).

3. The resource-based defluorination crystallization device according to claim 2, characterized in that: The precipitation zone (3) includes a conical precipitation chamber (301) fixedly connected to the lower surface of the reaction vessel body (1). A crystal discharge tube (302) is fixedly connected to the lower surface of the conical precipitation chamber (301). The crystal discharge tube (302) is controlled by a valve. The primary reaction zone (6) includes multiple connecting plates (601) fixedly connected to the lower surface of the effluent tank (201). A primary reaction tank (602) with a conical bottom is fixedly connected to the lower surface of the connecting plate (601). The primary reaction tank (602) has a cavity inside for the reaction of sewage and reagents. A flow channel is formed between two adjacent connecting plates (601).

4. The resource-based defluorination crystallization device according to claim 3, characterized in that: The mixing zone (5) includes a mixing pipe (501) that is fixedly connected to the lower surface of the primary reaction vessel (602), and a number of stainless steel plates (502) are welded to the inner cavity of the mixing pipe (501). The water inlet area (4) includes a conical water inlet chamber (401) that is fixedly connected to the lower surface of the mixing pipe (501). The lower surface of the water inlet chamber is fixedly connected to a water inlet pipe (402), a seed crystal dosing pipe (403), a first reagent dosing pipe (404), and a second reagent dosing pipe (405).

5. The resource-based defluorination crystallization device according to claim 4, characterized in that: A stirring assembly (7) is also provided inside the primary reaction zone (6) and the secondary reaction zone (101). The stirring assembly (7) includes a drive shaft (701) that passes through the water outlet chamber (201) and is rotatably connected to it, and a plurality of driven shafts (702). One end of the drive shaft (701) extends into the interior of the primary reaction zone (6), and the other end extends into the exterior of the water outlet chamber (201). One end of the driven shaft (702) extends into the interior of the secondary reaction zone (101), and the other end extends into the exterior of the water outlet chamber (201). The drive shaft (701) and the plurality of driven shafts (702) are respectively located inside the primary reaction zone (6) and the secondary reaction zone (101) and are fixedly connected with a plurality of stirring blades (703). The drive shaft (701) and two adjacent driven shafts (702) are driven by a pulley assembly. The two adjacent driven shafts (702) are driven by a pulley assembly.

6. The resource-based defluorination crystallization device according to claim 5, characterized in that: The water inlet pipe (402), seed crystal dosing pipe (403), first reagent dosing pipe (404), and second reagent dosing pipe (405) all penetrate the sedimentation tank and extend to its exterior.

7. The resource-based defluorination crystallization device according to claim 6, characterized in that: The end of the return pipe (208) away from the circulating water pump (207) passes through the sedimentation tank and is fixedly connected to the inlet tank.

8. The resource-based defluorination crystallization device according to claim 7, characterized in that: A support plate (8) is fixedly connected to the upper surface of the water outlet chamber (201), and a motor (801) is fixedly connected to the upper surface of the support plate (8). The output end of the motor (801) is fixedly connected to one end of the drive shaft (701) located outside the water outlet chamber (201).

9. The resource-based defluorination crystallization device according to claim 8, characterized in that: The first reagent dosing tube (404) and the second reagent dosing tube (405) are selected with different reagents and seed crystals according to different effluent water quality requirements. The effluent fluoride concentration is required to be less than or equal to 8 mg / L, and fluorite seed crystals and calcium chloride and calcium hydroxide reagents are used. The effluent fluoride concentration should be less than or equal to 1 mg / L. Fluoroapatite seed crystals are used, and phosphate and calcium chloride reagents are employed.

10. A resource-based defluorination crystallization device according to claim 9, characterized in that: The concentration of the seed crystals added by the seed crystal dosing tube (403) is not less than 8 g / L.

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