Crystallization promoter, preparation method thereof and wastewater treatment device

Abstract

The embodiment of the invention provides a crystallization promoter, a preparation method thereof and a wastewater treatment device. The crystallization promoter is used for removing target ions in wastewater, and comprises a slide glass, the density of which is smaller than that of the wastewater; and the seed crystal is arranged on the surface of the slide glass and is used for promoting the target ions to form crystals. The crystallization promoter can reduce the energy consumption of a wastewater treatment device.

Description

Technical Field

[0001] The present application relates to the field of water treatment technology, and in particular to a crystallization promoter and a preparation method thereof, and a wastewater treatment device. Background Art

[0002] With the rapid development of industries such as chemical materials, electronics, new energy, and semiconductors, the amount of wastewater discharged has increased significantly, and the discharge standards for wastewater have become increasingly stringent. Fluorine, phosphorus, heavy metals, etc. in wastewater usually have high biological toxicity and strong ecological destructiveness, so wastewater needs to be treated. Among them, fluorine-containing wastewater is usually treated by calcium salt precipitation-coagulation, and the reagents used in coagulation treatment include at least one of polyaluminium chloride (PAC) and polyacrylamide (PAM). However, the above treatment has problems such as high sludge moisture content, large sludge volume, large amount of reagents added, and large equipment footprint. In addition, the sludge contains fluorine, and its treatment as solid waste waste wastes fluorine resources.

[0003] In order to improve the above problems, fluoride-containing wastewater is treated by fluidized crystallization, which combines fluidized bed technology and induced crystallization technology. By adding crystal seeds to the reactor, fluoride in the wastewater is induced to heterogeneously nucleate and grow on its surface to form crystalline particles and then recover fluorine resources, overcoming the problems of large amount of traditional sedimentary sludge and high water content. Using the fluidized crystallization method, crystallization can occur when the fluoride ion concentration is low, which can effectively remove fluorine. And the corresponding area is in a fluidized state, with good solid-liquid mass transfer and energy transfer effects. Compared with traditional static crystallization and stirred crystallization, it is easier to achieve uniform mixing and shorten the required crystallization time. By controlling the flow rate, an ideal crystal particle size can also be formed, so it has the advantages of cleanliness, environmental protection, and low consumption.

[0004] However, the energy consumption of the above-mentioned treatment method of fluidized crystallization is relatively high. Summary of the invention

[0005] The embodiments of the present application provide a crystallization promoter and a preparation method thereof, and a wastewater treatment device to reduce energy consumption.

[0006] The embodiment of the present application provides a crystallization promoter for removing target ions in wastewater, and the crystallization promoter includes:

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

[0008] A seed crystal is disposed on the surface of the carrier to promote the target ion to form a crystal.

[0009] In some possible embodiments, the material of the carrier sheet includes at least one of polypropylene and polyethylene; and / or

[0010] The material of the seed crystal includes at least one of calcite, quartz sand, calcium carbonate and calcium fluoride.

[0011] In some possible implementations, the particle size of the seed crystal is 0.125 mm-0.180 mm, and the particle size of the carrier is 1-5 mm.

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

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

[0014] The present application also provides a method for preparing a crystallization promoter, comprising:

[0015] grinding and sieving the initial seed crystals to form seed crystals;

[0016] mixing the seed crystals with a carrier wafer;

[0017] heating the mixed seed crystal and the carrier sheet to soften the surface of the carrier sheet and adhere the seed crystal to form 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] The embodiment of the present application also provides a wastewater treatment device, comprising: a device body, and a crystallization promoter as described above disposed in the device body;

[0021] The device body comprises a fluidizing zone, and the seed crystals of the crystallization promoter promote the target ions in the wastewater to form crystals in the fluidizing zone.

[0022] In some possible embodiments, 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 crystals in the fluidized zone;

[0023] The device body further comprises a disengagement zone, which is arranged at the bottom of the fluidization zone;

[0024] The crystallization promoter sinks to the separation zone as the crystals increase, and floats to the fluidization zone again after being separated from the crystals.

[0025] In some possible embodiments, the dimension of the disengagement zone adjacent to one end of the fluidization zone is larger than the dimension of the disengagement zone away from one end of the fluidization zone, so as to increase the flow rate of the disengagement zone and separate the crystals from the crystallization promoter.

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

[0027] The size of the first subarea gradually decreases in a direction away from the fluidizing zone.

[0028] In some possible implementations, the second partition and the fluidizing zone are both columns;

[0029] Taking the plane perpendicular to the axis of the cylinder as the cross section, the cross-sectional diameter of the second partition is 1 / 3-1 / 2 of the cross-sectional diameter of the fluidizing zone.

[0030] In some possible implementations, the device body further includes a water outlet area, which is disposed at the top of the fluidizing area. The water outlet area is provided with a first water outlet for discharging the treated wastewater.

[0031] In some possible implementations, the device body further includes a water distribution area, the water distribution area is 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 water inlet for sedimentation treatment.

[0033] In some possible implementations, the water distribution area is further provided with a drug adding port, and the drug adding port is used to allow the precipitant to enter the water distribution area.

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

[0035] The pipeline connects the water outlet area and the water distribution area, and the circulation pump pumps the treated wastewater in the water outlet area into the water distribution area, and fluidizes the crystallization promoter in the fluidization area.

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

[0037] A first sieve plate, disposed between the water outlet area and the fluidizing area, for preventing the crystallization promoter from entering the water outlet area;

[0038] The second sieve plate is arranged between the water distribution area and the separation area, and is used for receiving the separated crystals.

[0039] In some possible implementations, the sieve holes of the first sieve plate have a diameter less than 1 mm; and / or

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

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

[0042] The feed inlet is used for the crystallization promoter to enter the fluidization zone;

[0043] The discharge port is arranged at one end of the fluidized zone away from the separation zone, so that the crystallization promoter can be discharged from the fluidized zone after the seed crystal is consumed.

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

[0045] The crystallization promoter and its preparation method and wastewater treatment device provided in the embodiments of the present application, the crystallization promoter includes a slide and a seed crystal, the density of the slide is less than the density of the wastewater, and the seed crystal is arranged on the surface of the slide, which is used to promote the crystallization of the target ion in the wastewater and attached to the crystallization promoter. By arranging the seed crystal on the slide, a mixture with low density and large volume is formed, the contact area with the target ion is increased and the density of the seed crystal is reduced, and fluidization is more easily achieved, the required reflux flow rate and equipment height are reduced, and the purpose of energy saving and consumption reduction is achieved. In addition, the seed crystal is attached to the slide to prevent the seed crystal from rushing into the effluent water and reduce the turbidity of the effluent water. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0047] Figure 1 is a schematic diagram of a crystallization promoter in an embodiment of the present application;

[0048] Figure 2 Schematic diagram of a crystallization promoter and a crystal in an example of the present application;

[0049] Figure 3 A schematic diagram of a failed crystallization promoter in an example of the present application;

[0050] Figure 4 is a flow chart of the method for preparing the crystallization promoter in the examples of the present application;

[0051] Figure 5 is a schematic diagram of a wastewater treatment device in an embodiment of the present application;

[0052] Figure 6 Schematic diagram of the crystallization promoters at different positions of the fluidized zone in the examples of the present application.

[0053] Description of reference numerals:

[0054] 10-crystallization promoter; 11-slide; 12-seed crystal; 13-crystal;

[0055] 20-water distribution area; 21-first water inlet; 22-second water inlet; 23-drug addition port;

[0056] 30-detachment zone; 31-crystal discharge port;

[0057] 40- fluidizing 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 DESCRIPTION

[0060] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0061] The wastewater treatment efficiency in the related art is low. The reason is that when the fluidized crystallization method is used to treat wastewater, corresponding crystal seeds need to be added to the wastewater. The density of these crystal seeds is greater than the density of wastewater, and it is necessary to maintain sufficient reflux flow to increase the rising flow rate in order to fluidize the crystal seeds, that is, it is difficult for the crystal seeds to be fluidized. Accordingly, when the flow rate increases, in order to ensure sufficient crystallization time, the height of the wastewater treatment device needs to be increased, thereby increasing the operating power consumption and cost. In addition, if the crystal seed particle size is too small, it is easy to make the effluent turbid, and even cause the circulation reflux pipeline to be blocked, affecting the normal operation of the wastewater treatment device.

[0062] To this end, the embodiment of the present application provides a crystallization promoter and a preparation method thereof, and a wastewater treatment device. The crystallization promoter includes a carrier and a seed crystal, the density of the carrier is less than the density of the wastewater, and the seed crystal is arranged on the surface of the carrier. By arranging the seed crystal on the carrier, a mixture with low density and large volume is formed, the contact area with the target ions in the wastewater is increased and the density of the seed crystal is reduced, so that fluidization is more easily achieved, the required reflux flow rate and the height of the equipment are reduced, and the purpose of energy saving and consumption reduction is achieved.

[0063] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of this application.

[0064] See also Figure 1 The embodiment of the present application provides a crystallization promoter 10 for removing target ions in 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 arranged on the surface of the carrier 11 to promote the target ions in the wastewater to form crystals 13.

[0065] By arranging (e.g., adhering) the seed crystal 12 on the carrier 11, a mixture with low density and large volume is formed, the contact area with the target ions is increased and the density of the seed crystal 12 is reduced, so that fluidization is more easily achieved, the required reflux flow rate and the height of related equipment are reduced, and the purpose of energy saving and consumption reduction is achieved. In addition, compared with directly using the seed crystal 12, the seed crystal 12 is attached to the carrier 11, which can prevent the seed crystal 12 from being washed into the effluent water, thereby reducing the turbidity of the effluent water.

[0066] Among them, the target ions of wastewater include fluorine, phosphorus, heavy metals (such as nickel, zinc, copper, iron, silver, lead, columbium, mercury), etc., that is, the wastewater can be defluorinated, dephosphorized, and deheavy metals removed, so that the treated wastewater meets the emission standards, reduces environmental pollution, and the crystal 13 can be recycled to improve resource utilization.

[0067] like Figure 1 As shown, the carrier sheet 11 is used for carrying, and the carrier sheet 11 does not react with the target ions in the wastewater. The density of the carrier sheet 11 is lower than the density of the wastewater, so that the carrier sheet 11 can 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] The seed crystal promotes the crystallization of the target ion to form crystals 13 and attach to the seed crystal 12, which can reduce the concentration of the target ion in the wastewater. Figure 1 and Figure 2 As the number of attached crystals 13 increases, the density of the crystallization promoter 10 increases, so that the crystallization promoter 10 can sink accordingly. As the attached crystals 13 detach, the density of the crystallization promoter 10 decreases, so that the crystallization promoter 10 can float accordingly. The crystallization promoter 10 moves up and down in the wastewater and fully reacts with the target ions in the wastewater without increasing the height of the device and the reflux flow rate, thereby improving efficiency and reducing energy consumption.

[0069] The seed crystals 12 are continuously consumed in this process, and their quantity gradually decreases. Figure 3 When the crystal seed 12 is consumed or almost consumed, the crystallization promoter 10 becomes ineffective. The ineffective crystallization promoter 10 is mainly the carrier 11, on which there is almost no crystal seed 12, and it is difficult to process the target ions. After the crystal 13 is separated, the ineffective crystallization promoter 10 has the lowest density and the lightest weight, and will rise to the highest point it can reach. At this time, the ineffective crystallization promoter 10 can be recovered, so as to continue to prepare new purified materials and realize repeated use.

[0070] In some possible embodiments, the density of the crystallization promoter 10 is 0.9 g / cm 3 -1.1 g / cm 3 , so as to achieve the sinking and floating of the crystal promoter 10 in the wastewater. It can be understood that as the number of crystal seeds 12 decreases, the density of the crystal promoter 10 will further decrease.

[0071] In the above example, the crystal form of the seed crystal 12 is the same as or similar to the crystal form of the target ion to promote the crystallization of the target ion. Exemplarily, the target ion includes fluorine, and the material of the seed crystal 12 includes at least one of calcite, quartz sand, calcium carbonate, and calcium fluoride. In this way, the density of the seed crystal 12 can be increased without affecting the contact between the seed crystal 12 and the chloride ions and calcium ions in the wastewater. Compared with directly scattering the seed crystal 12, it is easier to achieve fluidization, reduce the required reflux flow and equipment height, and save energy and reduce consumption. At the same time, it can prevent extremely fine seed crystals 12 from being washed into the effluent by the water flow, causing the effluent to be turbid.

[0072] The material of the carrier sheet 11 includes at least one of polypropylene (PP) and polyethylene (PE). In this way, the carrier sheet 11 as a master batch has a low density and does not react with the target ions, and can be reused. In addition, the carrier sheet 11 is made of the above material and can be softened by heating, so that the seed crystal 12 is adhered to facilitate the formation of the crystallization promoter 10.

[0073] In order to improve the efficiency of the crystallization promoter 10, the particle size of the seed crystal 12 is 0.125 mm-0.180 mm, and the particle size of the carrier 11 is 1-5 mm. In this way, a plurality of seed crystals 12 can be attached to the carrier 11, and the distribution of the seed crystals 12 is as uniform as possible, so that the density of the seed crystals 12 on the carrier 11 is appropriate, thereby improving the efficiency. Among them, the mass ratio of the seed crystals 12 to the carrier 11 is 1:5-1:10, so as to achieve fluidization.

[0074] like Figure 1 and Figure 2As shown, the seed crystal 12 promotes the crystallization of the target ion to form a crystal 13, and the particle size of the crystal 13 is larger than that of the seed crystal 12. For example, the particle size of the seed crystal 12 is 0.125 mm-0.180 mm, and the particle size of the mature crystal 13 is 1 mm-5 mm. The larger particle size of the crystal 13 also facilitates the crystal 13 to be separated from the carrier 11. After the seed crystal 12 is consumed, the crystallization promoter 10 fails, as shown in FIG. Figure 3 As shown, there are almost no seeds 12 on the carrier 11 of the failed crystallization promoter 10.

[0075] The crystallization promoter 10 in the embodiment of the present application includes a carrier sheet 11 and a seed crystal 12. The density of the carrier sheet 11 is less than the density of the wastewater. The seed crystal 12 is arranged on the surface of the carrier sheet 11 to promote the target ions in the wastewater to form crystals 13 and attach to the crystallization promoter 10. By arranging the seed crystal 12 on the carrier sheet 11, a mixture with low density and large volume is formed, the contact area with the target ions is increased and the density of the seed crystal 12 is reduced, fluidization is more easily achieved, the required reflux flow rate and the height of related equipment are reduced, and the purpose of energy saving and consumption reduction is achieved. In addition, the seed crystal 12 is attached to the carrier sheet 11 to prevent the seed crystal 12 from being flushed into the effluent water and reduce the turbidity of the effluent water.

[0076] See also Figure 4 The present application also provides a crystallization promoter 10 ( Figure 1 The preparation method of the present invention specifically comprises: grinding and screening the initial seed crystals to form the seed crystals 12; mixing the seed crystals 12 with the carrier 11; heating the mixed seed crystals 12 and the carrier 11 to soften the surface of the carrier 11 and adhere the seed crystals 12 to form a crystallization promoter 10; and cooling, washing and drying the 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 the floating objects are collected for drying. The drying temperature of the crystallization promoter 10 is 60°C to 80°C, 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 particle size of the seed crystal 12 is 0.125 mm-0.180 mm, the particle size of the carrier 11 is 1-5 mm, the mass ratio of the seed crystal 12 to the carrier 11 is 1:5-1:10, and the density of the crystallization promoter 10 is 0.9 g / cm 3 -1.1 g / cm 3 , thus, the performance of the crystallization promoter 10 is better.

[0079] The preparation method of the crystallization promoter 10 in the embodiment of the present application includes: grinding and sieving the initial seed crystals to form the seed crystals 12; mixing the seed crystals 12 with the carrier 11; heating the mixed seed crystals 12 and the carrier 11 to soften the surface of the carrier 11, adhere the seed crystals 12, and form the crystallization promoter 10; cooling, washing, and drying the crystallization promoter 10. The formed crystallization promoter 10 has a low density and a large volume, which increases the contact area with the target ions and reduces the density of the seed crystals 12, making it easier to achieve fluidization, reduce the required reflux flow rate and equipment height, and achieve the purpose of energy saving and consumption reduction. In addition, the seed crystals 12 are attached to the carrier 11 to prevent the seed crystals 12 from being washed into the effluent water, reducing the turbidity of the effluent water.

[0080] See also Figure 1 , Figure 2 , Figure 5 and Figure 6 The embodiment of the present application also provides a wastewater treatment device, including a device body and a crystallization promoter 10 disposed in the device body. The device body includes a fluidized zone 40, and the fluidized zone 40 is in a fluidized state. The crystal seeds 12 of the crystallization promoter 10 promote the crystallization of target ions in the wastewater to form crystals 13 in the fluidized 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 further includes a separation zone 30, which is disposed at the bottom of the fluidized zone 40; the crystallization promoter 10 sinks to the separation zone 30 as the crystals 13 increase, and floats back to the fluidized zone 40 after being separated from the crystals 13. In this way, the target ions in the wastewater can be removed by crystallization to reduce the pollution of the wastewater.

[0082] like Figure 5 and Figure 6 As shown, the separation zone 30 and the fluidization zone 40 are sequentially arranged from bottom to top, and the bottom end of the fluidization zone 40 is connected to the top end of the separation zone 30. The crystallization promoter 10 tumbles and fluidizes in the fluidization zone 40, and the fluidization zone 40 is in a fluidized state, so that the seed crystal 12 is fully in contact with the target ion, inducing the crystallization of the target ion, for example, promoting the reaction of chloride ions and calcium ions to produce calcium chloride crystals, near the surface of the seed crystal 12. Exemplarily, the water chemical conditions and hydraulic parameters in the fluidization zone 40 are: pH value is 8~9; fluidization velocity is 0.001m / s~0.002m / s.

[0083] The crystallization promoter 10 increases in density with the increase of crystals 13, sinks to the separation zone 30, and is separated from the crystals 13 in the separation zone 30. After being separated from the crystals 13, the density of the crystallization promoter 10 decreases, and it automatically rises to the fluidized zone 40 under the action of hydraulic pressure, and the remaining seed crystals 12 repeatedly induce the crystallization of the target particles, and continue to be separated in the separation zone 30. After the seed crystals 12 are almost completely detached, the crystallization promoter 10 becomes ineffective, and at this time, the density of the crystallization promoter 10 is the lowest and it is suspended at the top of the fluidized zone 40.

[0084] like Figure 6 As shown, failed crystallization promoters 10 are distributed at the top of the fluidized zone 40 , crystallization promoters 10 with mature crystals 13 are distributed at the bottom of the fluidized zone 40 , and crystallization promoters 10 with seed crystals 12 are distributed in the middle of the fluidized zone 40 .

[0085] The fluidized zone 40 is also provided with a feed port 41 and a discharge port 42; the feed port 41 is provided for the crystallization promoter 10 to enter the fluidized zone 40; the discharge port 42 is provided at one end of the fluidized zone 40 away from the separation zone 30, for the crystallization promoter 10 to discharge from the fluidized zone 40 after the crystal seed 12 is consumed.

[0086] As the crystals 13 fall off the crystallization promoter 10, the density of the crystallization promoter 10 decreases, and the crystal seed 12 is automatically floated, and the crystal seed 12 is continuously consumed. A discharge port 42 is provided at one end of the fluidized zone 40 away from the separation zone 30, which corresponds to the floating crystallization promoter 10 and is opposite to the failed crystallization promoter 10, so as to facilitate the discharge of the failed crystallization promoter 10 for recycling. The feed port 41 can also be provided at one end of the fluidized zone 40 away from the separation zone 30, and the crystallization promoter 10 is replenished to the fluidized zone 40 through the feed port 41, so as to ensure the continuous operation of the wastewater treatment device and the working efficiency.

[0087] In some possible examples, the size of the end of the separation zone 30 adjacent to the fluidization zone 40 is larger than the size of the end of the separation zone 30 away from the fluidization zone 40, so as to increase the flow rate of the separation zone 30 and separate the crystal 13 from the crystallization promoter 10. The above-mentioned size refers to the cross-sectional size perpendicular to the extension direction, such as Figure 5 As shown, the size of the bottom of the separation zone 30 is small, and the size of the top of the separation zone 30 is large, so that the flow rate at the bottom of the separation zone 30 is fast, the shear force of the water flow is large, and the attached crystals 13 can be automatically washed down, so that the crystals 13 and the crystallization promoter 10 can be separated, and the crystallization promoter 10 can promote crystallization multiple times. The separated crystals 13 have a large density and will sink, so the crystals 13 can be recycled to improve the utilization rate of resources.

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

[0089] Along the direction from the fluidized zone 40 to the second partition, the size of the first partition gradually shrinks, and the size from the top to the bottom of the first partition gradually decreases, so that the flow rate of the first partition gradually increases, so as to gradually increase the shear force of the water flow on the crystal 13, so that the shear force is adapted to the crystal 13, thereby flushing the crystal 13 off the crystallization promoter 10.

[0090] The precipitated crystals 13 can be collected in the second partition and discharged to achieve resource recycling. In some possible embodiments, the second partition and the fluidized zone 40 are both cylinders; with the plane perpendicular to the axis of the cylinder as the cross section, the cross-sectional diameter of the second partition is 1 / 3-1 / 2 of the cross-sectional diameter of the fluidized zone 40, so that the separation effect of the crystallization promoter 10 and the crystal 13 is better. Among them, the second partition and the fluidized zone 40 are both cylindrical, and the first partition is a truncated cone. In other examples, the first partition and the fluidized zone 40 are columns of other shapes, 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 area 50, which is arranged at the top of the fluidizing area 40. The water outlet area 50 is provided with a first water outlet 51 for discharging the treated wastewater so as to reuse the treated wastewater. The first water outlet 51 can be arranged at the top of the water outlet area 50 and connected to a corresponding pipeline. The number, position and shape of the first water outlet 51 are not limited in the embodiment of the present application.

[0092] The device body also includes a water distribution area 20, which is arranged at the bottom of the separation area 30. The water distribution area 20 is provided with a first water inlet 21; wastewater enters the water distribution area 20 through the first water inlet 21 for precipitation treatment. The water distribution area 20 is provided to perform precipitation treatment on the wastewater, so that non-target ions in the wastewater can be precipitated and separated to form a supersaturated solution containing target ions, which is convenient for subsequent crystallization.

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

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

[0095] Continue reading Figure 5 The device body also includes a pipeline 63 and a circulation pump 64 disposed on the pipeline 63; the pipeline 63 connects the water outlet area 50 and the water distribution area 20, and the circulation pump 64 pumps the treated wastewater in the water outlet area 50 into the water distribution area 20, and fluidizes the crystallization promoter 10 in the fluidization area 40. By using the circulation pump 64 and the pipeline 63, the treated wastewater can be pumped into the water distribution area 20, which can dilute the wastewater on the one hand, so that the wastewater and the precipitant can be fully mixed, and on the other hand, the flow rate of the wastewater can be increased, so that the wastewater enters the separation area 30 at a faster speed, and realizes fluidization in the fluidization area 40.

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

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

[0098] The first sieve plate 61 can intercept the crystallization promoter 10 and, to a certain extent, can intercept the fine crystals 13 produced by homogeneous nucleation during the debugging stage, thereby reducing the turbidity of the effluent water. At the same time, the failed crystallization promoter 10 is suspended to the bottom of the first sieve plate 61, which is convenient for discharging the failed crystallization promoter 10.

[0099] The second sieve plate 62 can intercept and recycle 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 attached crystals 13 are automatically washed down by the increased shear force of the water flow, and the crystals 13 are deposited on the second sieve plate 62 and discharged, thereby realizing the recovery of the crystals 13.

[0100] In some possible embodiments, the disengagement zone 30 is further provided with a crystal discharge port 31, which is arranged at one end of the disengagement zone 30 away from the fluidization zone 40, for the crystals 13 to be discharged from the disengagement zone 30. The crystal discharge port 31 is adjacent to the second sieve plate 62 to facilitate the discharge of the crystals 13. Exemplarily, 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 is described in detail below in combination with the specific structure of the wastewater treatment device.

[0102] like Figure 5 and Figure 6 As shown, the wastewater treatment device includes a water distribution area 20, a second sieve plate 62, a separation area 30, a fluidization area 40, a first sieve plate 61 and a water outlet area 50 which are arranged in sequence from bottom to top. The water distribution area 20 is provided with a dosing port 23, a first water inlet 21 and a second water inlet 22, and a second sieve plate 62 is provided at the bottom of the water distribution area 20. A crystal discharge port 31 is provided at the bottom of the separation area 30, a crystallization promoter 10 is provided in the fluidization area 40, and a feed port 41 and a discharge port 42 are provided. A first sieve plate 61 is provided at the top of the fluidization area 40, and a discharge port 42 is provided below the first sieve plate 61. The water outlet area 50 is provided with a first water outlet 51 and a second water outlet 52.

[0103] The wastewater contains fluoride. When the wastewater treatment device works normally, the wastewater enters the water distribution area 20 through the first water inlet 21, and the calcium chloride solution and the sodium hydroxide solution enter the water distribution area 20 through the dosing port 23. After the wastewater is fully contacted and mixed with the calcium chloride and the sodium hydroxide in the water distribution area 20, a supersaturated calcium fluoride solution is formed. The supersaturated calcium fluoride solution enters the fluidization area 40 through the second sieve plate 62, and contacts with the crystallization promoter 10 added from the feed port 41. At the same time, by adjusting the water inlet flow rate (i.e., the flow rate of the first water inlet 21) and the reflux flow rate (i.e., the flow rate of the second water inlet 22), the crystallization promoter 10 is tumbled and fluidized in the fluidization area 40.

[0104] The seed crystals 12 adhered to the surface of the carrier 11 induce the fluoride ions and calcium ions in the wastewater to react to generate calcium fluoride crystals 13, which 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 shedding zone, the cross-sectional area of ​​the shedding zone is smaller than that of the fluidization zone 40, the shear force of the water flow increases, and the calcium fluoride crystals 13 attached to the surface of the seed crystals 12 are automatically washed down, deposited on the second sieve plate 62, and discharged through the crystal discharge port 31.

[0105] After the calcium fluoride crystals 13 fall off, the density of the crystallization promoter 10 decreases, and it automatically rises to the fluidized zone 40 under the action of hydraulic pressure. The seed crystals 12 remaining on its surface repeatedly induce the fluoride ions and calcium ions in the wastewater to react to generate calcium fluoride crystals 13 and fall off the calcium fluoride crystals 13 again in the separation zone 30. When the seed crystals 12 of the crystallization promoter 10 are almost completely fallen off, the crystallization promoter 10 becomes ineffective, the density decreases and it is suspended 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 is running, the number of crystallization promoters 10 gradually decreases. The feed port 41 is opened, and the crystallization promoter 10 is added to supplement the fluidized zone 40, so as to further improve the defluorination capacity of the wastewater treatment device and realize the continuous operation of the wastewater treatment device.

[0106] The wastewater treatment device in the embodiment of the present application includes a device body and a crystallization promoter 10 arranged in the device body. The device body includes a fluidized zone 40, which is in a fluidized state. The crystal seeds 12 of the crystallization promoter 10 promote the crystallization of the target ions in the wastewater to form crystals 13 in the fluidized zone 40. The crystallization promoter 10 includes a carrier 11 and a crystal seed 12. The density of the carrier 11 is less than the density of the wastewater, and the crystal seed 12 is arranged on the surface of the carrier 11. By arranging the crystal seed 12 on the carrier 11, a mixture with low density and large volume is formed, which increases the contact area with the target ions and reduces the density of the crystal seed 12, making it easier to achieve fluidization, reduce the required reflux flow rate and equipment height, and achieve the purpose of energy saving and consumption reduction. In addition, the crystal seed 12 is attached to the carrier 11 to prevent the crystal seed 12 from being flushed into the effluent water and reduce the turbidity of the effluent water.

[0107] In this specification, each embodiment or implementation is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referenced to each other. The description of reference terms such as "one implementation", "some implementations", "illustrative implementations", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the implementation or example are included in at least one implementation or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same implementation or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more implementations or examples in a suitable manner.

[0108] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A crystallization promoter, characterized in that: For removing target ions in wastewater, the crystallization promoter comprises: A slide, wherein the density of the slide is less than the density of the wastewater; A seed crystal is disposed on the surface of the carrier to promote the target ion to form a crystal.

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

3. The crystallization promoter according to claim 1, characterized in that The particle size of the seed crystal is 0.125 mm-0.180 mm, and the particle size of the carrier is 1-5 mm.

4. The crystallization promoter according to claim 1, characterized in that The mass ratio of the seed crystal to the carrier wafer is 1:5 to 1:

10.

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

6. A method for preparing a crystallization promoter, characterized in that: include: grinding and sieving the initial seed crystals to form seed crystals; mixing the seed crystals with a slide; heating the mixed seed crystal and the carrier sheet to soften the surface of the carrier sheet and adhere the seed crystal to form the crystallization promoter; The crystallization promoter is cooled, washed and dried.

7. The preparation method according to claim 6, characterized in that: The drying temperature of the crystallization promoter is 60°C to 80°C.

8. A wastewater treatment device, characterized in that: include: A device body, and a crystallization promoter as claimed in any one of claims 1 to 5 arranged in the device body; The device body comprises a fluidizing zone, and the seed crystals of the crystallization promoter promote the target ions in the wastewater to form crystals in the fluidizing zone.

9. The wastewater treatment device according to claim 8, characterized in that: The device body further comprises a disengagement zone, which is arranged at the bottom of the fluidization zone; The crystallization promoter sinks to the separation zone as the crystals increase, and floats to the fluidization zone again after being separated from the crystals.

10. The wastewater treatment device according to claim 9, characterized in that: The dimension of the disengagement zone adjacent to one end of the fluidization zone is larger than the dimension of the disengagement zone away from one end of the fluidization zone, so as to increase the flow velocity of the disengagement zone and separate the crystals from the crystallization promoter.

11. The wastewater treatment device according to claim 10, characterized in that: The disengagement zone includes a first partition and a second partition, one end of the first partition is connected to the fluidization zone, and the other end is connected to the second partition; The size of the first subarea gradually decreases in a direction away from the fluidizing zone.

12. The wastewater treatment device according to claim 11, characterized in that: The second partition and the fluidizing zone are both cylindrical; Taking the plane perpendicular to the axis of the cylinder as the cross section, the cross-sectional diameter of the second partition is 1 / 3-1 / 2 of the cross-sectional diameter of the fluidizing zone.

13. The wastewater treatment device according to claim 10, characterized in that: The device body also includes a water outlet area, which is arranged on the top of the fluidization area. The water outlet area is provided with a first water outlet for discharging the treated wastewater.

14. The wastewater treatment device according to claim 13, characterized in that: The device body further comprises a water distribution area, the water distribution area is arranged 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 water inlet for sedimentation treatment.

15. The wastewater treatment device according to claim 14, characterized in that: The water distribution area is also provided with a drug adding port, and the drug adding port is used for the precipitant to enter the water distribution area.

16. The wastewater treatment device according to claim 15, characterized in that: The device body also includes a pipeline, and a circulation pump arranged on the pipeline; The pipeline connects the water outlet area and the water distribution area, and the circulation pump pumps the treated wastewater in the water outlet area into the water distribution area, and fluidizes the crystallization promoter in the fluidization area.

17. The wastewater treatment device according to claim 14, characterized in that: The device body also includes: A first sieve plate, disposed between the water outlet area and the fluidizing area, for preventing the crystallization promoter from entering the water outlet area; The second sieve plate is arranged between the water distribution area and the separation area, and is used for receiving the separated crystals.

18. The wastewater treatment device according to claim 17, characterized in that: The sieve holes of the first sieve plate have a diameter of less than 1 mm; and / or The aperture of the sieve holes of the second sieve plate is 0.125 mm-0.18 mm.

19. The wastewater treatment device according to any one of claims 9 to 18, characterized in that: The fluidized zone is also provided with a feed inlet and a discharge outlet; The feed inlet is used for the crystallization promoter to enter the fluidization zone; The discharge port is arranged at one end of the fluidized zone away from the separation zone, so that the crystallization promoter can be discharged from the fluidized zone after the seed crystal is consumed.

20. The wastewater treatment device according to any one of claims 9 to 18, characterized in that: The separation zone is also provided with a crystal discharge port, which is arranged at one end of the separation zone away from the fluidization zone for the crystals to be discharged from the separation zone.

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