Crystal nucleating body, method for producing the same, and wastewater treatment device

Abstract

The embodiment of the present application provides a crystallization promoting body, a preparation method thereof and a wastewater treatment device. The crystallization promoting body is used for removing target ions in wastewater. The crystallization promoting body comprises: a carrier sheet, the density of the carrier sheet is less than the density of the wastewater; and crystal seeds, the crystal seeds are arranged on the surface of the carrier sheet and used for promoting the target ions to form crystals. The crystallization promoting body can reduce the energy consumption of the wastewater treatment device.

Description

Technical Field

[0001] This application relates to the field of water treatment technology, and in particular to a crystallization promoter and its preparation method, and a wastewater treatment device. Background Technology

[0002] With the rapid development of industries such as chemical materials, electronics, new energy, and semiconductors, wastewater discharge has increased significantly, and wastewater discharge standards have become increasingly stringent. Wastewater often contains highly toxic substances such as fluoride, phosphorus, and heavy metals, which have strong biological toxicity and ecological destructive power, thus requiring treatment. Fluoride-containing wastewater typically undergoes calcium salt precipitation-coagulation treatment, using at least one of polyaluminum chloride (PAC) or polyacrylamide (PAM) as coagulation agents. However, this treatment method suffers from problems such as high sludge moisture content, large sludge volume, large reagent dosage, and large equipment footprint. Furthermore, the fluoride-containing sludge, when treated as solid waste, wastes fluoride resources.

[0003] To address the aforementioned issues, fluidized bed crystallization (FBC) is employed to treat fluoride-containing wastewater. This method combines fluidized bed technology with induced crystallization. By adding seed crystals to the reactor, fluoride in the wastewater is induced to nucleate and grow heterogeneously on its surface, forming crystalline particles and thus recovering fluoride resources. This overcomes the problems of large sludge volume and high water content associated with traditional sedimentation methods. Fluidized bed crystallization allows crystallization to occur even at low fluoride ion concentrations, effectively removing fluoride. Furthermore, the fluidized state within the affected area provides excellent solid-liquid mass and energy transfer, making it easier to achieve uniform mixing and shortening the required crystallization time compared to traditional static and stirred crystallization methods. By controlling the flow rate, ideal crystal particle sizes can also be formed, resulting in advantages such as cleanliness, environmental friendliness, and low energy consumption.

[0004] However, the above-mentioned treatment method using fluidized bed crystallization has high energy consumption. Summary of the Invention

[0005] This application provides a crystallization promoter and its preparation method, as well as a wastewater treatment device, to reduce energy consumption.

[0006] This application provides a crystallization promoter for removing target ions from wastewater, the crystallization promoter comprising:

[0007] A slide, the density of which is less than the density of the wastewater;

[0008] Seed crystals are disposed on the surface of the substrate to promote the formation of crystals from the target ions.

[0009] In some possible implementations, the carrier sheet is made of at least one of polypropylene and polyethylene; and / or

[0010] The seed crystal is made of at least one of calcite, quartz sand, calcium carbonate, and calcium fluoride.

[0011] In some possible implementations, the seed crystals have a particle size of 0.125 mm to 0.180 mm, and the substrate has a particle size of 1 to 5 mm.

[0012] In some possible implementations, the mass ratio of the seed crystal to the carrier is 1:5 to 1:10.

[0013] In some possible embodiments, the density of the crystallization promoter is 0.9 g / cm³. 3 -1.1 g / cm 3 .

[0014] This application also provides a method for preparing a crystallization promoter, including:

[0015] The initial seed crystals are ground and sieved to form seed crystals;

[0016] The seed crystals are mixed with the carrier wafer;

[0017] The mixed seed crystals and the carrier are heated to soften the surface of the carrier, causing the seed crystals to adhere and forming the crystallization promoter.

[0018] The crystallization promoter is cooled, washed, and dried.

[0019] In some possible implementations, the drying temperature of the crystallization promoter is 60°C to 80°C.

[0020] This application embodiment also provides a wastewater treatment device, including: a device body, and a crystallization promoter disposed in the device body as described above;

[0021] The device body includes a fluidization zone, where the seed crystals of the crystallization promoter promote the formation of crystals from target ions in the wastewater.

[0022] In some possible implementations, the target ion is a target ion, the seed crystal is a seed crystal, and the seed crystal promotes the crystallization of the target ion to form a crystal in the fluidization zone;

[0023] The device body also includes a separation zone, which is disposed at the bottom of the fluidization zone;

[0024] The crystallization promoter sinks to the detachment zone as the number of crystals increases, separates from the crystals, and then floats back to the fluidization zone.

[0025] In some possible implementations, the size of the detachment zone at the end adjacent to the fluidization zone is larger than the size of the detachment zone at the end away from the fluidization zone, in order to increase the flow rate of the detachment zone and separate the crystal from the crystallization promoter.

[0026] In some possible implementations, the de-fluidization zone includes a first partition and a second partition, with one end of the first partition connected to the fluidization zone and the other end connected to the second partition;

[0027] The size of the first partition gradually decreases along the direction away from the fluidization region.

[0028] In some possible implementations, both the second partition and the fluidization zone are cylindrical.

[0029] Taking a plane perpendicular to the axis of the column as a cross section, the diameter of the second section is 1 / 3 to 1 / 2 of the diameter of the fluidized zone.

[0030] In some possible implementations, the device body further includes a water outlet zone disposed at the top of the fluidization zone, the water outlet zone having a first water outlet for discharging the treated wastewater.

[0031] In some possible implementations, the device body further includes a water distribution area disposed at the bottom of the separation area, and the water distribution area is provided with a first water inlet;

[0032] The wastewater enters the water distribution area through the first inlet for sedimentation treatment.

[0033] In some possible implementations, the water distribution zone is also provided with a dosing port for the flocculant to enter the water distribution zone.

[0034] In some possible implementations, the device body further includes a pipe and a circulation pump disposed on the pipe;

[0035] The pipeline connects the outlet area and the distribution area. The circulating pump pumps the treated wastewater from the outlet area into the distribution area, and causes the crystallization promoter to fluidize in the fluidization zone.

[0036] In some possible implementations, the device body further includes:

[0037] A first sieve plate is disposed between the water outlet zone and the fluidization zone to prevent the crystallization promoter from entering the water outlet zone;

[0038] A second sieve plate is disposed between the water distribution zone and the separation zone to receive the separated crystals.

[0039] In some possible implementations, the aperture of the sieve holes in the first sieve plate is less than 1 mm; and / or

[0040] The aperture of the second sieve plate is 0.125 mm-0.18 mm.

[0041] In some possible implementations, the fluidization zone is further provided with a feed inlet and a discharge outlet;

[0042] The feed inlet allows the crystallization promoter to enter the fluidization zone;

[0043] The discharge port is located at one end of the fluidization zone away from the detachment zone, so that the crystallization promoter consumed by the seed crystals can be discharged from the fluidization zone.

[0044] In some possible implementations, the detachment zone is further provided with a crystal discharge port, which is located at one end of the detachment zone away from the fluidization zone, for the crystal to be discharged from the detachment zone.

[0045] The crystallization promoter, its preparation method, and wastewater treatment device provided in this application include a crystallization promoter comprising a carrier and seed crystals. The density of the carrier is less than that of the wastewater. The seed crystals are disposed on the surface of the carrier to promote the crystallization of target ions in the wastewater and adhere to the crystallization promoter. By placing seed crystals on the carrier, a mixture with low density and large volume is formed, increasing the contact area with the target ions and reducing the density of the seed crystals. This makes fluidization easier, reducing the required reflux flow rate and equipment height, thus achieving energy saving and consumption reduction. Furthermore, the seed crystals adhering to the carrier prevent them from being washed into the effluent, reducing turbidity in the effluent. Attached Figure Description

[0046] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0047] Figure 1 This is a schematic diagram of the crystallization promoter in the embodiments of this application;

[0048] Figure 2 This is a schematic diagram of the crystallization promoter and crystal in the embodiments of this application;

[0049] Figure 3 This is a schematic diagram of a failed crystallization promoter in an embodiment of this application;

[0050] Figure 4 This is a flowchart of the preparation method of the crystallization promoter in the embodiments of this application;

[0051] Figure 5 This is a schematic diagram of the wastewater treatment device in the embodiments of this application;

[0052] Figure 6 This is a schematic diagram of crystallization promoters at different locations in the fluidization zone in the embodiments of this application.

[0053] Explanation of reference numerals in the attached figures:

[0054] 10-Crystallization promoter; 11-Slide carrier; 12-Seed crystal; 13-Crystal;

[0055] 20 - Water distribution area; 21 - First water inlet; 22 - Second water inlet; 23 - Chemical dosing port;

[0056] 30 - Detachment zone; 31 - Crystal discharge port;

[0057] 40 - Fluidization zone; 41 - Feed inlet; 42 - Discharge outlet;

[0058] 50 - Water outlet area; 51 - First water outlet; 52 - Second water outlet;

[0059] 61-First sieve plate; 62-Second sieve plate; 63-Pipeline; 64-Circulation pump. Detailed Implementation

[0060] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0061] The wastewater treatment efficiency in related technologies is relatively low because fluidized bed crystallization requires the addition of seed crystals to the wastewater. These seed crystals have a higher density than the wastewater, necessitating a sufficient reflux flow rate to increase the upward flow velocity and maintain the seed crystals in a fluidized state; consequently, the seed crystals are difficult to fluidize. Consequently, as the flow rate increases, the height of the wastewater treatment unit must be increased to ensure sufficient crystallization time, thus increasing operating power consumption and costs. Furthermore, excessively small seed crystal size can easily cause turbidity in the effluent and even clog the recirculation pipeline, affecting the normal operation of the wastewater treatment unit.

[0062] Therefore, this application provides a crystallization promoter and its preparation method, as well as a wastewater treatment device. The crystallization promoter includes a carrier and seed crystals. The density of the carrier is less than that of the wastewater, and the seed crystals are disposed on the surface of the carrier. By placing seed crystals on the carrier, a mixture with low density and large volume is formed, increasing the contact area with target ions in the wastewater and reducing the density of the seed crystals. This makes it easier to achieve fluidization, reduces the required reflux flow rate and equipment height, and achieves energy saving and consumption reduction.

[0063] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0064] See Figure 1 This application provides a crystallization promoter 10 for removing target ions from wastewater. The crystallization promoter 10 includes a carrier 11 and a seed crystal 12. The density of the carrier 11 is less than the density of the wastewater. The seed crystal 12 is disposed on the surface of the carrier 11 to promote the formation of crystals 13 from the target ions in the wastewater.

[0065] By setting (e.g., adhering) seed crystals 12 on the carrier 11, a mixture with low density and large volume is formed, increasing the contact area with the target ions and reducing the density of the seed crystals 12. This makes fluidization easier, reduces the required reflux flow rate and the height of related equipment, and achieves energy saving and consumption reduction. Furthermore, since the seed crystals 12 are attached to the carrier 11, compared to using the seed crystals 12 directly, it is possible to avoid the seed crystals 12 being washed into the effluent, thus reducing turbidity in the effluent.

[0066] The target ions in the wastewater include fluoride, phosphorus, and heavy metals (such as nickel, zinc, copper, iron, silver, lead, columbus, and mercury). In other words, the wastewater can be defluorinated, dephosphorized, and demetallized to ensure that the treated wastewater meets the discharge standards, reduce environmental pollution, and allow for the recovery of crystal 13, thereby improving resource utilization.

[0067] like Figure 1 As shown, the carrier 11 is used to support the target ions in the wastewater and does not react with them. The density of the carrier 11 is lower than that of the wastewater, allowing the carrier 11 to float relative to the wastewater. The density of the wastewater can be the density of the original wastewater, the density of the diluted wastewater, or the density of the wastewater after sedimentation treatment.

[0068] Seed crystals promote the crystallization of target ions, forming crystal 13 which then attaches to seed crystal 12, thereby reducing the concentration of target ions in wastewater. Furthermore, see [link to relevant documentation]. Figure 1 and Figure 2 As the number of attached crystals 13 increases, the density of the crystallization promoter 10 increases, allowing it to sink. Conversely, as the attached crystals 13 detach, the density of the crystallization promoter 10 decreases, allowing it to float. The crystallization promoter 10 moves up and down in the wastewater, fully reacting with the target ions without requiring increased device height or reflux flow rate, thus improving efficiency and reducing energy consumption.

[0069] Seed crystal 12 is continuously consumed during this process, and its quantity gradually decreases. (See also...) Figure 3 When the seed crystal 12 is consumed or nearly consumed, the crystallization promoter 10 becomes ineffective. The ineffective crystallization promoter 10 is mainly the carrier 11, which has almost no seed crystal 12 on it and can no longer process the target ions. After the crystal 13 detaches, the ineffective crystallization promoter 10 has the lowest density and lightest mass, and will rise to the highest point it can reach. At this time, the ineffective crystallization promoter 10 can be recycled to continue preparing new purifiers and achieve reuse.

[0070] In some possible implementations, the density of the crystallization promoter 10 is 0.9 g / cm³. 3 -1.1 g / cm 3 This is to achieve the settling and floating of the crystallization promoter 10 in the wastewater. Understandably, as the number of seed crystals 12 decreases, the density of the crystallization promoter 10 will further decrease.

[0071] In the above example, the crystal form of seed crystal 12 is the same as or similar to that of the target ion to promote the crystallization of the target ion. For example, the target ion includes fluorine, and the material of seed crystal 12 includes at least one of calcite, quartz sand, calcium carbonate, and calcium fluoride. This increases the density of seed crystal 12 without affecting its contact with chloride and calcium ions in the wastewater. Compared to directly sprinkling seed crystal 12, fluidization is easier to achieve, reducing the required return flow rate and equipment height, thus saving energy and reducing consumption. Simultaneously, it prevents extremely fine seed crystals from being washed into the effluent by the water flow, causing turbidity in the effluent.

[0072] The carrier 11 is made of at least one of polypropylene (PP) and polyethylene (PE). Thus, the carrier 11, as a masterbatch, has a low density, does not react with the target ions, and can be reused. Furthermore, the carrier 11, made of the aforementioned material, can be softened by heating, thereby allowing the seed crystals 12 to adhere and facilitating the formation of the crystallization promoter 10.

[0073] To improve the efficiency of the crystallization promoter 10, the seed crystals 12 have a particle size of 0.125 mm-0.180 mm, and the carrier 11 has a particle size of 1-5 mm. This allows multiple seed crystals 12 to be attached to the carrier 11, with the seed crystals 12 distributed as evenly as possible to achieve a suitable density and improve efficiency. The mass ratio of seed crystals 12 to carrier 11 is 1:5 to 1:10 to facilitate fluidization.

[0074] like Figure 1 and Figure 2As shown, seed crystal 12 promotes the crystallization of target ions to form crystal 13. The particle size of crystal 13 is larger than that of seed crystal 12. For example, the particle size of seed crystal 12 is 0.125 mm-0.180 mm, while the particle size of mature crystal 13 is 1 mm-5 mm. The larger particle size of crystal 13 also facilitates its detachment from the carrier 11. After seed crystal 12 is consumed, the crystallization promoter 10 becomes ineffective. Figure 3 As shown, there are almost no seed crystals 12 on the substrate 11 of the failed crystallization promoter 10.

[0075] The crystallization promoter 10 in this embodiment includes a carrier 11 and seed crystals 12. The density of the carrier 11 is less than that of the wastewater. The seed crystals 12 are disposed on the surface of the carrier 11 to promote the formation of crystals 13 from target ions in the wastewater, which then adhere to the crystallization promoter 10. By disposing of the seed crystals 12 on the carrier 11, a mixture with low density and large volume is formed, increasing the contact area with the target ions and reducing the density of the seed crystals 12. This makes fluidization easier, reduces the required reflux flow rate and the height of related equipment, and achieves energy saving and consumption reduction. Furthermore, the seed crystals 12 are attached to the carrier 11, preventing them from being washed into the effluent and reducing turbidity in the effluent.

[0076] See Figure 4 This application also provides a crystallization promoter 10 ( Figure 1 The preparation method (shown) specifically includes: grinding and sieving the initial seed crystal to form seed crystal 12; mixing seed crystal 12 with carrier 11; heating the mixed seed crystal 12 and carrier 11 to soften the surface of carrier 11 and adhere seed crystal 12 to form crystallization promoter 10; cooling, washing and drying crystallization promoter 10.

[0077] The heating temperature is the softening temperature of the carrier 11, the crystallization promoter 10 is cooled to room temperature, tap water is used for washing, and floating matter is collected and dried. The drying temperature of the crystallization promoter 10 is 60℃~80℃, which is lower than the softening temperature of the carrier 11. The material of the carrier 11 includes at least one of polypropylene and polyethylene; and / or the material of the seed crystal 12 includes at least one of calcite, quartz sand, calcium carbonate, and calcium fluoride.

[0078] In some possible embodiments, the seed crystal 12 has a particle size of 0.125 mm-0.180 mm, the carrier 11 has a particle size of 1-5 mm, the mass ratio of seed crystal 12 to carrier 11 is 1:5 to 1:10, and the density of the crystallization promoter 10 is 0.9 g / cm³. 3 -1.1 g / cm 3 Thus, the performance of crystallization promoter 10 is better.

[0079] The preparation method of the crystallization promoter 10 in this embodiment includes: grinding and sieving an initial seed crystal to form a seed crystal 12; mixing the seed crystal 12 with a carrier plate 11; heating the mixed seed crystal 12 and carrier plate 11 to soften the surface of the carrier plate 11 and adhere the seed crystal 12, forming the crystallization promoter 10; and cooling, washing, and drying the crystallization promoter 10. The resulting crystallization promoter 10 has a low density and large volume, increasing the contact area with the target ions and reducing the density of the seed crystal 12, making it easier to achieve fluidization, reducing the required reflux flow rate and equipment height, and achieving energy saving and consumption reduction. Furthermore, the seed crystal 12 adheres to the carrier plate 11, preventing it from being washed into the effluent and reducing turbidity in the effluent.

[0080] See Figure 1 , Figure 2 , Figure 5 and Figure 6 This application also provides a wastewater treatment device, including a device body and a crystallization promoter 10 disposed within the device body. The device body includes a fluidization zone 40, in which a fluidized state is maintained. The seed crystals 12 of the crystallization promoter 10 promote the crystallization of target ions in the wastewater to form crystals 13 within the fluidization zone 40. The specific structure of the crystallization promoter 10 can be referred to above and will not be repeated here.

[0081] In some possible examples, the device body also includes a separation zone 30, which is located at the bottom of the fluidization zone 40; the crystallization promoter 10 sinks to the separation zone 30 as the crystals 13 increase, separates from the crystals 13, and then floats back to the fluidization zone 40. In this way, crystallization can be used to remove target ions from wastewater, reducing wastewater pollution.

[0082] like Figure 5 and Figure 6 As shown, the desorption zone 30 and the fluidization zone 40 are arranged sequentially from bottom to top, with the bottom end of the fluidization zone 40 connected to the top end of the desorption zone 30. The crystallization promoter 10 tumbles and fluidizes within the fluidization zone 40, creating a fluidized state to ensure sufficient contact between the seed crystal 12 and the target ions, inducing the crystallization of the target ions, for example, promoting the reaction of chloride ions and calcium ions to produce calcium chloride crystals, which are located near the surface of the seed crystal 12. For example, the water chemistry conditions and hydraulic parameters within the fluidization zone 40 are: pH value of 8-9; fluidization velocity of 0.001 m / s-0.002 m / s.

[0083] As the number of crystals 13 increases, the density of the crystallization promoter 10 increases, causing it to sink to the separation zone 30, where it separates from the crystals 13. After separation from the crystals 13, the density of the crystallization promoter 10 decreases, and it automatically rises to the fluidization zone 40 under hydraulic action. The remaining seed crystals 12 then repeatedly induce the crystallization of the target particles, and separation continues in the separation zone 30. Once the seed crystals 12 have almost completely detached, the crystallization promoter 10 becomes ineffective. At this point, the density of the crystallization promoter 10 is at its lowest, and it floats at the top of the fluidization zone 40.

[0084] like Figure 6 As shown, the top of the fluidization zone 40 is distributed with failed crystallization promoters 10, the bottom of the fluidization zone 40 is distributed with crystallization promoters 10 containing mature crystals 13, and the middle part of the fluidization zone 40 is distributed with crystallization promoters 10 containing seed crystals 12.

[0085] The fluidization zone 40 is also provided with a feed inlet 41 and a discharge outlet 42. The feed inlet 41 allows the crystallization promoter 10 to enter the fluidization zone 40. The discharge outlet 42 is located at the end of the fluidization zone 40 away from the separation zone 30, and allows the crystallization promoter 10 consumed by the seed crystal 12 to be discharged from the fluidization zone 40.

[0086] As crystals 13 detach from the crystallization promoter 10, the density of the crystallization promoter 10 decreases, causing it to float automatically. Meanwhile, the seed crystals 12 are continuously consumed. A discharge port 42 is provided at the end of the fluidization zone 40 furthest from the detachment zone 30, corresponding to the floating crystallization promoter 10 and the deactivated crystallization promoter 10, facilitating the discharge and recycling of the deactivated crystallization promoter 10. Alternatively, a feed port 41 can be located at the end of the fluidization zone 40 furthest from the detachment zone 30. Replenishing the fluidization zone 40 with crystallization promoter 10 through the feed port 41 ensures continuous operation of the wastewater treatment device and guarantees working efficiency.

[0087] In some possible examples, the dimension of the detachment zone 30 at the end adjacent to the fluidization zone 40 is larger than the dimension of the detachment zone 30 at the end away from the fluidization zone 40, in order to increase the flow rate of the detachment zone 30 and separate the crystal 13 from the crystallization promoter 10. The aforementioned dimensions refer to the cross-sectional dimensions perpendicular to the extension direction, such as... Figure 5 As shown, the bottom of the separation zone 30 is small, while the top is large, resulting in a high flow velocity and strong shear force at the bottom. This automatically washes away the attached crystals 13, separating them from the crystallization promoter 10 and allowing the crystallization promoter 10 to promote crystallization multiple times. The detached crystals 13, being denser, will sink and can be recycled, improving resource utilization.

[0088] The decoupling zone 30 includes a first zone and a second zone. One end of the first zone is connected to the fluidization zone 40, and the other end is connected to the second zone. The size of the first zone gradually decreases in the direction away from the fluidization zone 40. Figure 5 As shown, the top of the first partition connects to the bottom of the fluidization zone 40, and the bottom of the first partition connects to the top of the second partition. The first partition connects the second partition and the fluidization zone 40, and the separation of crystal 13 and crystallization promoter 10 mainly occurs in the first partition.

[0089] Along the direction from the fluidization zone 40 to the second zone, the size of the first zone gradually shrinks, and the size from the top to the bottom of the first zone gradually decreases, so that the flow velocity of the first zone gradually increases, thereby gradually increasing the shear force of the water flow on the crystal 13, so that the shear force is adapted to the crystal 13, thereby washing the crystal 13 off the crystallization promoter 10.

[0090] The precipitated crystals 13 can be collected in the second partition and discharged, achieving resource recycling. In some possible embodiments, both the second partition and the fluidization zone 40 are cylindrical; taking a plane perpendicular to the axis of the cylinder as the cross-section, the diameter of the second partition is 1 / 3 to 1 / 2 of the diameter of the fluidization zone 40, thus achieving better separation of the crystallization promoter 10 and the crystals 13. Specifically, both the second partition and the fluidization zone 40 are cylindrical, while the first partition is a frustum. In other examples, the first partition and the fluidization zone 40 are cylindrical in shape, and the cross-sectional diameter refers to the equivalent diameter of the corresponding cross-section.

[0091] Continue reading Figure 5 The device body also includes a water outlet zone 50, which is located at the top of the fluidization zone 40. The water outlet zone 50 is provided with a first water outlet 51 for discharging treated wastewater for reuse. The first water outlet 51 can be located at the top of the water outlet zone 50 and connected to a corresponding external pipeline. The number, location, and shape of the first water outlet 51 are not limited in this embodiment.

[0092] The device also includes a water distribution zone 20, which is located at the bottom of the separation zone 30. The water distribution zone 20 is equipped with a first inlet 21. Wastewater enters the water distribution zone 20 through the first inlet 21 for sedimentation treatment. By setting up the water distribution zone 20 to perform sedimentation treatment on the wastewater, non-target ions in the wastewater can be separated and precipitated to form a supersaturated solution containing target ions, which facilitates subsequent crystallization.

[0093] like Figure 5As shown, the water distribution zone 20 is located at the bottom of the separation zone 30 and away from the fluidization zone 40. The water distribution zone 20, separation zone 30, fluidization zone 40, and effluent zone 50 are connected sequentially from bottom to top. The water distribution zone 20 is also provided with a dosing port 23, which allows flocculant to enter the water distribution zone 20 so that the flocculant can treat the wastewater. There can be one or more dosing ports 23, which are connected to corresponding pipelines. The dosing ports 23 are spaced apart from the first inlet 21, for example, the dosing ports 23 and the first inlet 21 are arranged opposite each other to facilitate connection to the corresponding pipelines.

[0094] For example, the wastewater contains fluoride ions, and the precipitant includes calcium chloride solution and sodium hydroxide solution. The calcium chloride solution and sodium hydroxide solution enter the water distribution zone 20 through two dosing ports 23, respectively. The fluoride-containing wastewater is fully contacted and mixed with calcium chloride and sodium hydroxide for precipitation treatment, and the wastewater after precipitation treatment forms a supersaturated calcium fluoride solution. In other examples, the precipitant includes sodium carbonate solution or other alkaline solutions.

[0095] Continue reading Figure 5 The device also includes a pipe 63 and a circulation pump 64 mounted on the pipe 63. The pipe 63 connects the effluent zone 50 and the distribution zone 20. The circulation pump 64 pumps the treated wastewater from the effluent zone 50 into the distribution zone 20, and fluidizes the crystallization promoter 10 in the fluidization zone 40. Using the circulation pump 64 and the pipe 63, the treated wastewater can be pumped into the distribution zone 20. This dilutes the wastewater, allowing it to mix thoroughly with the precipitant. It also increases the flow rate of the wastewater, enabling it to enter the separation zone 30 at a faster speed, thus achieving fluidization within the fluidization zone 40.

[0096] In some possible implementations, the water outlet zone 50 is provided with a second water outlet 52, the water distribution zone 20 is provided with a second water inlet 22, one end of the pipe 63 is connected to the second water outlet 52, and the other end of the pipe 63 is connected to the second water inlet 22. A circulation pump 64 is provided on the pipe 63 to increase the flow velocity at the second water inlet 22. The second water outlet 52 is lower than the first water outlet 51 to ensure the return flow into the water distribution zone 20. The second water inlet 22 can be located at the bottom of the water distribution zone 20.

[0097] Continue reading Figure 5 The device body also includes a first sieve plate 61 and a second sieve plate 62. The first sieve plate 61 is disposed between the water outlet zone 50 and the fluidization zone 40 to prevent the crystallization promoter 10 from entering the water outlet zone 50. The second sieve plate 62 is disposed between the water distribution zone 20 and the separation zone 30 to receive the separated crystals 13. In some possible examples, the aperture of the sieve holes of the first sieve plate 61 is less than 1 mm; and / or the aperture of the sieve holes of the second sieve plate 62 is 0.125 mm to 0.18 mm.

[0098] The first sieve plate 61 can intercept the crystallization promoter 10 and, to some extent, the fine crystals 13 generated during homogeneous nucleation in the commissioning stage, thereby reducing the turbidity of the effluent. At the same time, the failed crystallization promoter 10 will float to the bottom of the first sieve plate 61, making it easier to discharge the failed crystallization promoter 10.

[0099] The second sieve plate 62 can intercept and recover the detached crystals 13, thereby achieving certain economic benefits. Specifically, when the crystals 13 attached to the surface of the seed crystal 12 grow to a certain particle size, the crystallization promoter 10 automatically sinks to the detachment zone 30, and the increased water flow shear force automatically washes the attached crystals 13 off. The crystals 13 are deposited on the second sieve plate 62 and discharged, thereby realizing the recovery of crystals 13.

[0100] In some possible implementations, the separation zone 30 is further provided with a crystal discharge port 31, which is located at the end of the separation zone 30 away from the fluidization zone 40, for discharging the crystals 13 from the separation zone 30. The crystal discharge port 31 is adjacent to the second sieve plate 62 to facilitate the discharge of the crystals 13. For example, the crystal discharge port 31, the dosing port 23, the feed port 41, and the second water outlet 52 can be arranged on the same side, and the first water inlet 21, the discharge port 42, and the first water outlet 51 can be arranged on the same side.

[0101] The working process of the wastewater treatment device will be described in detail below, taking into account its specific structure.

[0102] like Figure 5 and Figure 6 As shown, the wastewater treatment device includes, from bottom to top, a water distribution zone 20, a second screen plate 62, a separation zone 30, a fluidization zone 40, a first screen plate 61, and an effluent zone 50. The water distribution zone 20 is equipped with a dosing port 23, a first inlet 21, and a second inlet 22. The second screen plate 62 is located at the bottom of the water distribution zone 20. The bottom of the separation zone 30 is equipped with a crystal discharge port 31. The fluidization zone 40 contains a crystallization promoter 10 and is equipped with an inlet 41 and an outlet 42. The top of the fluidization zone 40 is equipped with the first screen plate 61, and the outlet 42 is located below the first screen plate 61. The effluent zone 50 is equipped with a first outlet 51 and a second outlet 52.

[0103] The wastewater contains fluoride. When the wastewater treatment device is working normally, the wastewater enters the water distribution zone 20 through the first inlet 21, while calcium chloride solution and sodium hydroxide solution enter the water distribution zone 20 through the dosing inlet 23. After the wastewater, calcium chloride, and sodium hydroxide are fully contacted and mixed in the water distribution zone 20, a supersaturated calcium fluoride solution is formed. The supersaturated calcium fluoride solution enters the fluidization zone 40 through the second sieve plate 62 and comes into contact with the crystallization promoter 10 added from the feed inlet 41. At the same time, by controlling the inlet flow rate (i.e., the flow rate of the first inlet 21) and the return flow rate (i.e., the flow rate of the second inlet 22), the crystallization promoter 10 is made to tumble and fluidize in the fluidization zone 40.

[0104] Seed crystals 12 adhered to the surface of the carrier 11 induce the reaction of fluoride ions and calcium ions in the wastewater to generate calcium fluoride crystals 13, which then adhere to the surface of the seed crystals 12. When the calcium fluoride crystals 13 grow to a certain particle size, as the density of the crystallization promoter 10 increases, the crystallization promoter 10 sinks to the detachment zone. The cross-sectional area of ​​the detachment zone is smaller than that of the fluidization zone 40, and the shear force of the water flow increases, which automatically washes the calcium fluoride crystals 13 attached to the surface of the seed crystals 12 off and deposits them on the second sieve plate 62, and then discharges them through the crystal discharge port 31.

[0105] After the calcium fluoride crystals 13 are detached, the density of the crystallization promoter 10 decreases. Under hydraulic action, it automatically rises to the fluidization zone 40. The seed crystals 12 remaining on its surface repeatedly induce the reaction between fluoride ions and calcium ions in the wastewater to generate calcium fluoride crystals 13, which then detach again in the separation zone 30. When the seed crystals 12 of the crystallization promoter 10 are almost completely detached, the crystallization promoter 10 becomes ineffective, its density decreases, and it floats below the first sieve plate 61. At this time, the discharge port 42 is opened to discharge the crystallization promoter 10. As the wastewater treatment device operates, the number of crystallization promoters 10 gradually decreases. The feed port 41 is opened to add crystallization promoters 10 to replenish the fluidization zone 40, further improving the defluorination capacity of the wastewater treatment device and enabling continuous operation of the wastewater treatment device.

[0106] The wastewater treatment device in this embodiment includes a device body and a crystallization promoter 10 disposed within the device body. The device body includes a fluidization zone 40, in which a fluidized state is maintained. The seed crystals 12 of the crystallization promoter 10 promote the crystallization of target ions in the wastewater to form crystals 13 within the fluidization zone 40. The crystallization promoter 10 includes a carrier plate 11 and a seed crystal 12. The density of the carrier plate 11 is less than that of the wastewater, and the seed crystal 12 is disposed on the surface of the carrier plate 11. By disposing of the seed crystal 12 on the carrier plate 11, a mixture with low density and large volume is formed, increasing the contact area with the target ions and reducing the density of the seed crystal 12, making fluidization easier to achieve, reducing the required return flow rate and equipment height, and achieving energy saving and consumption reduction. Furthermore, the seed crystal 12 is attached to the carrier plate 11, preventing the seed crystal 12 from being washed into the effluent and reducing turbidity of the effluent.

[0107] The embodiments or implementation methods described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with an embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0108] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A crystallization promoter, characterized in that, For removing target ions from wastewater, the crystallization promoter comprises: A slide, the density of which is less than the density of the wastewater; Seed crystals, disposed on the surface of the substrate, are used to promote the formation of crystals from the target ions; The seed crystals have a particle size of 0.125 mm to 0.180 mm, and the carrier has a particle size of 1 to 5 mm. The mass ratio of the seed crystal to the carrier is 1:5 to 1:

10.

2. The crystallization promoter according to claim 1, characterized in that, The carrier sheet is made of at least one of polypropylene and polyethylene; and / or The seed crystal is made of at least one of calcite, quartz sand, calcium carbonate, and calcium fluoride.

3. The crystallization promoter according to claim 1, characterized in that, The density of the crystallization promoter is 0.9 g / cm³. 3 -1.1 g / cm 3 .

4. A method for preparing a crystallization promoter, characterized in that, include: The initial seed crystals are ground and sieved to form seed crystals; The seed crystals are mixed with the carrier wafer; The mixed seed crystals and the carrier are heated to soften the surface of the carrier, causing the seed crystals to adhere and forming the crystallization promoter. The crystallization promoter is cooled, washed, and dried. The density of the carrier is less than that of the wastewater; the particle size of the seed crystal is 0.125 mm-0.180 mm, and the particle size of the carrier crystal is 1-5 mm; the mass ratio of the seed crystal to the carrier crystal is 1:5 to 1:

10.

5. The preparation method according to claim 4, characterized in that, The drying temperature of the crystallization promoter is 60℃~80℃.

6. A wastewater treatment device, characterized in that, include: The device body, and the crystallization promoter disposed within the device body as described in any one of claims 1-3; The device body includes a fluidization zone, and the seed crystals of the crystallization promoter promote the formation of crystals from target ions in the wastewater within the fluidization zone; The device body also includes a separation zone, which is disposed at the bottom of the fluidization zone; The crystallization promoter sinks to the detachment zone as the number of crystals increases, separates from the crystals, and then floats back to the fluidization zone; The size of the detachment zone at the end adjacent to the fluidization zone is larger than the size of the detachment zone at the end away from the fluidization zone, so as to increase the flow rate of the detachment zone and separate the crystal from the crystallization promoter.

7. The wastewater treatment apparatus according to claim 6, characterized in that, The decomposition zone includes a first partition and a second partition, with one end of the first partition connected to the fluidization zone and the other end connected to the second partition; The size of the first partition gradually decreases along the direction away from the fluidization region.

8. The wastewater treatment apparatus according to claim 7, characterized in that, Both the second partition and the fluidized zone are cylindrical. Taking a plane perpendicular to the axis of the column as a cross section, the diameter of the second section is 1 / 3 to 1 / 2 of the diameter of the fluidized zone.

9. The wastewater treatment apparatus according to claim 6, characterized in that, The device body also includes a water outlet zone, which is located at the top of the fluidization zone and has a first water outlet for discharging the treated wastewater.

10. The wastewater treatment apparatus according to claim 9, characterized in that, The device body also includes a water distribution area, which is located at the bottom of the separation area, and the water distribution area is provided with a first water inlet; The wastewater enters the water distribution area through the first inlet for sedimentation treatment.

11. The wastewater treatment apparatus according to claim 10, characterized in that, The water distribution area is also equipped with a chemical dosing port, which supplies precipitant into the water distribution area.

12. The wastewater treatment apparatus according to claim 11, characterized in that, The device body also includes a pipe and a circulation pump installed on the pipe; The pipeline connects the outlet area and the distribution area. The circulating pump pumps the treated wastewater from the outlet area into the distribution area, and causes the crystallization promoter to be fluidized in the fluidization zone.

13. The wastewater treatment apparatus according to claim 10, characterized in that, The device body also includes: A first sieve plate is disposed between the water outlet zone and the fluidization zone to prevent the crystallization promoter from entering the water outlet zone; A second sieve plate is disposed between the water distribution zone and the separation zone to receive the separated crystals.

14. The wastewater treatment apparatus according to claim 13, characterized in that, The aperture of the sieve holes in the first sieve plate is less than 1 mm; and / or The aperture of the second sieve plate is 0.125mm-0.18mm.

15. The wastewater treatment apparatus according to any one of claims 6-14, characterized in that, The fluidization zone is also provided with a feed inlet and a discharge outlet; The feed inlet allows the crystallization promoter to enter the fluidization zone; The discharge port is located at one end of the fluidization zone away from the detachment zone, so that the crystallization promoter consumed by the seed crystals can be discharged from the fluidization zone.

16. The wastewater treatment apparatus according to any one of claims 6-14, characterized in that, The detachment zone is also provided with a crystal discharge port, which is located at one end of the detachment zone away from the fluidization zone, for the crystals to be discharged from the detachment zone.

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