Continuous treatment process and system for high-fluorine-content wastewater in fluorine chemical industry

Abstract

The invention discloses a continuous treatment process and system for fluorine chemical high-fluorine-content wastewater, and relates to the technical field of fluorine wastewater treatment.The continuous treatment process comprises the following steps that 1, the high-fluorine-content wastewater is introduced into a collecting tank with a stirring device to be homogenized, and a regulator is added to adjust the pH to 8.0-9.0; a continuous overflow design is adopted to maintain stable retention time, and then the next link is entered; 2, calcium fluoride precipitation: introducing the adjusted wastewater into a reaction tank with a stirring device, adding CaCl2 according to the molar ratio of fluorine ions to calcium ions of 2: 1.05-2: 1.2, and stirring and mixing to enable F <-> and Ca < 2 + > to react to generate CaF2 precipitation; and 3, introducing the precipitate-containing wastewater into a mud-water separation system. Continuous treatment of the high-fluorine-content wastewater is achieved, the treatment efficiency is high, the large-scale industrial wastewater treatment requirement is met, sludge backflow serves as a seed crystal, invalid consumption of CaCl2 and other agents is reduced, the treatment process is simplified through the Lanmela precipitation device, the operation cost and capital construction investment are reduced, and good economical efficiency is achieved.

Description

Technical Field

[0001] This invention relates to the field of fluoride wastewater treatment technology, specifically to a continuous treatment process and system for high-fluoride-content wastewater from fluoride chemical industries. Background Technology

[0002] Fluorine and its compounds are widely used in chemical, metallurgical, electronic, and electroplating industries, and the resulting high-fluoride wastewater has become one of the important sources of industrial pollution.

[0003] Currently, the main methods for treating high-fluoride wastewater include chemical precipitation, adsorption, and membrane separation. Among these, chemical precipitation is the most widely used method in industry due to its simple process and low cost. Its core principle is to separate fluoride ions by adding calcium ions, which converts fluoride ions into water-insoluble calcium fluoride precipitate. Several patents for fluoride wastewater treatment based on chemical precipitation already exist. For example, Chinese patent CN119841408A discloses a deep fluoride removal method for wastewater based on NH4F·LaF3 chemical precipitation. This method removes fluoride by adding a solution containing NH4+ and La3+ to generate a low-solubility double salt. While it can ensure that the effluent fluoride concentration meets standards, the lanthanide reagents used are expensive, lack continuity, and are difficult to scale up for industrial application.

[0004] Existing patents and treatment processes related to chemical precipitation still have many technical defects: their continuous treatment systems have poor adaptability and cannot stably meet the needs of large-scale industrial wastewater treatment; the efficiency of mud-water separation is low; traditional sedimentation tanks or simple sedimentation devices occupy a large area and have poor treatment effects; there is a lack of a sound process monitoring and dynamic control mechanism; and the risk of direct discharge of unqualified wastewater is high. Summary of the Invention

[0005] The purpose of this invention is to provide a continuous treatment process and system for high-fluoride wastewater from fluorochemical industries, in order to overcome the shortcomings of the prior art.

[0006] To achieve the above objectives, the present invention provides a continuous treatment process for high-fluoride wastewater from fluorochemical industries, comprising the following steps:

[0007] Step 1: Introduce the high-fluoride wastewater into a collection tank equipped with a stirring device for homogenization;

[0008] Add a pH adjuster to 8.0-9.0; after maintaining a stable residence time using a continuous overflow design, proceed to the next stage;

[0009] Step 2: Calcium fluoride precipitation: The adjusted wastewater is introduced into a reaction tank equipped with a stirring device, and CaCl2 is added at a ratio of fluoride to calcium ions of 2:1.05-2:1.2. The mixture is then stirred to allow F- to react with Ca2+ to form CaF2 precipitate.

[0010] Step 3: Introduce the wastewater containing sediment into the sludge-water separation system, add PAC and PAM sequentially, and then enter the Lamella sedimentation unit; start the sludge return system to return part of the CaF2 sludge as seed crystals;

[0011] Step 4: Monitor the fluoride concentration and pH of the effluent in real time;

[0012] If the fluoride concentration exceeds the standard, the wastewater will be returned to the coagulation reaction section for retreatment. If it meets the standard, it will be discharged directly or enter into advanced treatment.

[0013] Preferably, in step 1, the regulator is a sodium hydroxide solution or a calcium hydroxide suspension, and the mass concentration of the regulator is 5%-10%.

[0014] Preferably, in step 3, the dosage of PAC is 50-100 mg / L, the dosage of PAM is 5-10 mg / L, and the interval between the addition of PAC and PAM is 5-10 min.

[0015] Preferably, in step 3, the inclination angle of the inclined plate in the Lamella sedimentation device is 40-50 degrees, and the residence time of the wastewater in the Lamella sedimentation device is 40-60 minutes.

[0016] Preferably, in step 4, the monitoring frequency of the online monitoring device is once every 5-10 minutes; the fluoride concentration exceeding the standard is determined by the effluent fluoride concentration > 5 mg / L.

[0017] A continuous treatment system for high-fluoride wastewater from fluorochemical industries, comprising:

[0018] The system includes a coagulation chamber, a sedimentation chamber, and a sludge chamber. Wastewater in the coagulation chamber is transported to the bottom of the sedimentation chamber via a conveying pipe. As the wastewater moves upwards along the sedimentation chamber, the flocculated material settles downwards into the sedimentation chamber. Filtered liquid overflows from the top of the sedimentation chamber. The system also includes:

[0019] Inclined plate assembly, a plurality of said inclined plate assemblies are arranged in parallel within the sedimentation chamber, said inclined plate assembly including a first filter plate and a second filter plate;

[0020] The first filter plate and the second filter plate are arranged parallel to each other, and the angle between them and the horizontal plane is set at 40-50 degrees.

[0021] Preferably, the first filter plate is fixedly installed in the sedimentation tank, the first filter plate has a material leakage port, the material leakage port is provided with a flip cover, the second filter plate and the first filter plate are linked together, and an elastic element is provided between the two.

[0022] Preferably, it also includes an unloading assembly, which includes a drive unit and a transmission unit. The drive unit is disposed on the upper part of the inclined plate assembly, and the drive unit and the flip cover are connected by the transmission unit.

[0023] Preferably, the driving unit includes a displacement plate, an unfolding plate, a guide groove, and a rotating column. The guide groove is formed on the second filter plate. The displacement plate is slidably connected to the top of the first filter plate. The unfolding plate is slidably connected to the displacement plate. The rotating column is rotatably connected to the unfolding plate. The lower part of the rotating column is rotatably connected to the guide groove.

[0024] Preferably, the transmission part includes a drive bar, a rotating shaft, a pin, and an annular groove. The drive bar is slidably connected to the side of the first filter plate. The upper part of the drive bar is arranged on the unfolding path of the unfolding plate. One end of the rotating shaft is fixedly installed on the flip cover. The annular groove is opened on the rotating shaft. The pin is fixedly installed on the drive bar. The other end of the pin is inserted into the annular groove.

[0025] In the above technical solution, the present invention provides a continuous treatment process and system for high-fluoride wastewater from fluorochemical industries. Through the continuous overflow design of the collection tank and the coordinated connection of each link, it breaks the intermittent treatment mode of the traditional process, realizes the continuous treatment of high-fluoride wastewater, has high treatment efficiency, and is suitable for the needs of large-scale industrial wastewater treatment. The sludge return as seed crystals reduces the ineffective consumption of reagents such as CaCl2, and the Lamellar precipitation device simplifies the treatment process, reduces operating costs and infrastructure investment, and has good economic benefits. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0027] Figure 1 This is a schematic diagram of a continuous treatment process for high-fluoride wastewater from a fluorochemical industry according to the present invention.

[0028] Figure 2 This is a schematic diagram of the overall structure of the continuous fluoride wastewater treatment system of the present invention;

[0029] Figure 3 This is a schematic diagram of the inclined plate assembly of the continuous fluoride wastewater treatment system of the present invention;

[0030] Figure 4 This invention provides an appendix to the continuous fluoride wastewater treatment system. Figure 3 Enlarged view of point A in the middle;

[0031] Figure 5 This invention provides an appendix to the continuous fluoride wastewater treatment system. Figure 3 Enlarged view of point B in the middle;

[0032] Figure 6This is a schematic diagram of the unfolded component of the continuous fluoride wastewater treatment system of the present invention after unfolding.

[0033] Figure 7 This invention provides an appendix to the continuous fluoride wastewater treatment system. Figure 6 A magnified diagram of point C in the middle;

[0034] Figure 8 This is a schematic diagram of the second filter plate of the continuous fluoride wastewater treatment system of the present invention after it moves toward the first filter plate;

[0035] Figure 9 This invention provides an appendix to the continuous fluoride wastewater treatment system. Figure 8 Enlarged view of point D;

[0036] Figure 10 This is a partial structural diagram of the drive unit of the continuous fluoride wastewater treatment system of the present invention;

[0037] Figure 11 This is a schematic diagram of the conveying pipe structure of the continuous fluoride wastewater treatment system of the present invention.

[0038] Explanation of reference numerals in the attached drawings: 1. Coagulation chamber; 2. Conveying pipe; 3. Sedimentation chamber; 4. Inclined plate assembly; 5. Sludge chamber; 6. Discharge assembly; 41. First filter plate; 42. Flip cover; 43. Second filter plate; 411. Discharge port; 61. Displacement plate; 62. Expanding plate; 63. Rotating column; 631. Guide groove; 64. Drive bar; 641. Pin; 66. Rotating shaft; 661. Annular groove. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0040] Please see Figure 1-11 The present invention provides a continuous treatment process for high-fluoride wastewater from fluorochemical industries, comprising the following steps:

[0041] Step 1: Introduce the high-fluoride wastewater into a collection tank equipped with a stirring device for homogenization;

[0042] The pH is adjusted to 8.0-9.0 by adding a regulator; after maintaining a stable residence time using a continuous overflow design, the process proceeds to the next stage. Specifically, high-fluoride wastewater is prone to fluctuations in fluoride concentration and pH during production. The stirring device in the collection tank can achieve uniform mixing of the physical properties and chemical components of the wastewater, avoiding insufficient precipitation due to uneven local concentrations in subsequent reactions, thus laying the foundation for stable operation of subsequent processes. By adjusting the pH to 8.0-9.0, on the one hand, it can prevent fluoride ions from combining with hydrogen ions to form HF under acidic conditions, which is difficult to react with calcium ions; on the other hand, it can prevent calcium ions from forming Ca(OH)2 precipitate when the alkalinity is too strong, ensuring that calcium ions can react efficiently with fluoride ions.

[0043] Step 2: Introduce the adjusted wastewater into a reaction tank equipped with a stirrer. Add CaCl2 at a fluoride to calcium ion molar ratio of 2:1.05-2:1.2, and then stir to mix. - With Ca 2+ The reaction produces CaF2 precipitate. Specifically, utilizing the extremely low solubility product constant of calcium fluoride, fluoride ions and calcium ions form a water-insoluble precipitate, achieving separation. CaCl2 is added at a fluoride to calcium ion molar ratio of 1:1.2-1.3. By employing an excess of calcium ions, the reaction equilibrium is shifted towards CaF2 formation, increasing the fluoride ion removal rate. Furthermore, the excess calcium ions inhibit the dissolution of the CaF2 precipitate, preventing secondary release of fluoride ions. The stirring device further enhances ion diffusion, reduces local concentration gradients, and ensures the separation of F- and Ca- ions. 2+ The reaction proceeds through full contact, producing CaF2 precipitate with uniform particle size that is easily separated.

[0044] Step 3: Introduce the wastewater containing sediment into the sludge-water separation system, add PAC and PAM sequentially, and then enter the Lamella sedimentation unit; start the sludge return system to return part of the CaF2 sludge as seed crystals; specifically, PAC, as an inorganic coagulant, hydrolyzes in water to generate polynuclear aluminum hydroxide complexes, which can cause tiny CaF2 precipitate particles to aggregate into larger flocs. Similarly, PAM, as an organic flocculant, uses its long-chain molecular structure to further aggregate the small flocs formed by PAC, forming large flocs that are easy to settle, thereby improving the sludge-water separation efficiency. A 5-10 minute dosing interval is set to allow... After PAC has fully completed the coagulation reaction, PAM is used to enhance the flocculation effect, avoiding direct mixing of the two agents which would cause mutual interference. The Lamera sedimentation device increases the sedimentation area and shortens the particle settling distance, allowing the flocs to settle quickly. Then, some CaF2 sludge is returned to the reaction system, using the CaF2 particles in the sludge as seed crystals. Newly generated CaF2 will preferentially grow on the surface of the seed crystals, forming larger and denser sediment particles, reducing secondary nucleation. This increases the sedimentation rate and reduces the ineffective consumption of CaCl2, thus eliminating the need for additional calcium ions to form new crystal nuclei.

[0045] Step 4: Monitor the fluoride concentration and pH of the effluent in real time;

[0046] If the fluoride concentration exceeds the standard, the wastewater will be redirected to the coagulation reaction section for retreatment. If it meets the standard, it will be directly discharged or enter advanced treatment. Specifically, the fluoride concentration and pH value will be monitored every 5-10 minutes to capture fluctuations in effluent quality in real time and promptly detect any decline in treatment effectiveness caused by changes in influent concentration or deviations in reagent dosage, thus preventing the direct discharge of unqualified wastewater. When the effluent fluoride concentration is >5 mg / L, the wastewater will be redirected to the coagulation reaction section through the redirection pipeline. The synergistic effect of PAC+PAM will be used to further enhance floc separation. At the same time, the seed crystal reflux system will supplement the reaction driving force to ensure that the final effluent fluoride concentration meets the standard.

[0047] In the embodiments of the present invention, in step 1, the regulator is a sodium hydroxide solution or a calcium hydroxide suspension, and the mass concentration of the regulator is 5%-10%. Specifically, using a 5%-10% sodium hydroxide solution or a calcium hydroxide suspension as the regulator ensures regulation efficiency, controls the dosage of the reagent, and reduces treatment costs. The calcium hydroxide suspension can also provide a small amount of calcium ions to assist the subsequent precipitation reaction.

[0048] In step 3, the dosage of PAC is 50-100 mg / L, and the dosage of PAM is 5-10 mg / L; the interval between the addition of PAC and PAM is 5-10 min.

[0049] In step 3, the inclined plate in the Lamella sedimentation unit has an inclination angle of 40-50 degrees, and the residence time of the wastewater in the Lamella sedimentation unit is 40-60 minutes. The inclination angle of 40-50 degrees can significantly increase the sedimentation area, thereby improving the treatment efficiency.

[0050] In step 4, the online monitoring device monitors once every 5-10 minutes; the fluoride concentration exceeding the standard is judged as effluent fluoride concentration > 5 mg / L.

[0051] Embodiments of the present invention:

[0052] project Example 1 (Medium-concentration fluoride wastewater) Example 2 (High-concentration fluoride wastewater) I. Wastewater Quality Conditions Treatment capacity: 10 m³ / h; Initial fluoride concentration: 80 mg / L; Initial pH: 6.2; Water temperature: 25℃; Other impurities: Contains a small amount of suspended solids (SS=30 mg / L) Treatment capacity: 8 m³ / h; Initial fluoride concentration: 200 mg / L; Initial pH: 5.8; Water temperature: 28℃; Other impurities: Contains trace amounts of sulfate and chloride. II. Process Operating Parameters <![CDATA[Stirring rate: 30 - 60 r / min; Regulator: 8% sodium hydroxide solution; Target pH value: 8.5; Residence time: 30 min; Stirring rate: 30 - 60 r / min; Fluorine-calcium molar ratio: 2:1.1; Dosage of CaCl2: 145 mg / L; Reaction time: 40 min; Dosage of PAC: 70 mg / L Dosage of PAM: 8 mg / L; Dosing interval: 8 min Lamella precipitation: Residence time 50 min; Inclination angle of inclined plate: 40° Sludge reflux ratio: 15%; Monitoring frequency: 1 time / 8 min Callback situation: Not exceeding the standard, no callback]]> <![CDATA[Stirring rate: 30 - 60 r / min; Regulator: 10% calcium hydroxide suspension; Target pH value: 8.8; Residence time: 40 min; Stirring rate: 30 - 60 r / min; Fluorine-calcium molar ratio: 2:1.05; CaCl2 dosage: 372 mg / L; Reaction time: 60 min; PAC dosage 100 mg / L PAM dosage: 10 mg / L; Dosage interval: 10 min; Lamella precipitation: Residence time 60 min; Inclination angle of inclined plate 50 degrees; Sludge reflux ratio: 20%; Monitoring frequency: 1 time / 5 min Callback situation: Exceeded the standard twice initially; After the reflux coagulation section, supplement PAC 30 mg / L and PAM 3 mg / L]]> III. Processing Results Effluent fluoride concentration: 0.72 mg / L; Effluent pH: 8.3; Fluoride removal rate: 99.1%; Effluent SS: 5 mg / L; Chemical consumption: No additional waste. <![CDATA[Fluoride concentration in effluent: 0.85 mg / L; pH value of effluent: 8.6; Fluoride removal rate: 99.57%; Chemical consumption: The consumption of CaCl2 is reduced by 12% compared with the process without reflux]]>

[0053] The above two examples, covering medium and high concentrations of fluoride-containing wastewater respectively, verified the process's adaptability to different water qualities. In Example 2, the over-standard callback mechanism successfully treated wastewater with insufficient initial reaction, demonstrating the reliability of closed-loop control. Furthermore, the application of the sludge return system was more effective in treating high-concentration wastewater, effectively reducing reagent consumption and verifying the process's economy. The final effluent fluoride concentration was all below 5 mg / L, meeting the national industrial wastewater discharge standards, proving the process's treatment efficiency and stability.

[0054] Based on the theory of shallow sedimentation, the Lamella sedimentation unit can divide the large-volume sedimentation zone of the sedimentation tank into multiple thin-layer sedimentation spaces, fundamentally shortening the particle settling distance and significantly increasing the effective sedimentation area. It has become the core equipment for mud-water separation in the treatment of high-fluoride wastewater in fluorochemical industry and is widely used in continuous treatment processes.

[0055] The sedimentation efficiency is highly correlated with the inclination angle of the inclined plate, exhibiting a trade-off: the horizontal projected area of ​​the inclined plate represents its actual effective sedimentation area, and the larger the inclination angle, the greater the increase in projected area for every 1-degree decrease in angle. Theoretically, a smaller inclination angle can significantly increase the effective sedimentation area, reduce the surface loading rate, and thus greatly improve sedimentation efficiency. However, a smaller angle will simultaneously reduce the sludge's sliding speed along the inclined plate, easily causing sludge to accumulate on the inclined plate surface and block the thin-layer sedimentation space, thereby losing the technical advantage of shallow sedimentation. Based on this, the inclination angle of the inclined plate in existing technologies for Lamella devices is generally selected within the equilibrium range of 55-60 degrees. This angle design ensures a certain effective sedimentation area and maintains basic sedimentation efficiency while allowing sludge to be discharged autonomously by gravity, avoiding sludge accumulation and blockage on the inclined plate, and is suitable for the sludge-water separation needs of conventional industrial wastewater.

[0056] However, considering the characteristics and continuous treatment requirements of high-fluoride wastewater from fluorochemical industries, the existing Lamellar units designed with an angle of 55-60 degrees have shown significant technical bottlenecks. On the one hand, the calcium fluoride flocs generated after calcium salt chemical precipitation and coagulation flocculation of high-fluoride wastewater from fluorochemical industries are characterized by fine particle size and slight viscosity. Their settling performance is weaker than that of suspended particles in conventional industrial wastewater. The effective sedimentation area at the existing angle can no longer further reduce the surface loading rate, and the sedimentation efficiency has reached its limit. It is difficult to achieve efficient and deep separation of calcium fluoride flocs, which easily leads to fluctuations in effluent fluoride concentration and fails to meet increasingly stringent wastewater discharge standards. On the other hand, if the sedimentation efficiency is improved by simply reducing the tilt angle of the inclined plate, although the sedimentation efficiency can be improved by significantly increasing the projected area, it will directly cause a sharp drop in the downward speed of calcium fluoride flocs. The flocs are very easy to adhere to, accumulate, and block the thin-layer channels on the inclined plate surface. This will not only gradually lose the advantage of shallow sedimentation, but also require frequent shutdowns for cleaning, which will seriously disrupt the process rhythm of continuous treatment of high-fluoride wastewater from fluorochemical industries and significantly increase equipment operation and maintenance costs and labor costs.

[0057] Therefore, we propose a continuous treatment system adapted to the characteristics of high-fluoride wastewater from fluorochemical industries. Through innovative design, we break through the traditional limitations of the angle design of the Lamella device, and achieve a reasonable reduction in the tilt angle of the inclined plate to significantly improve the sedimentation efficiency, while effectively solving the problem of sludge accumulation and blockage caused by small angles.

[0058] A continuous treatment system for high-fluoride wastewater from fluorochemical industries includes a coagulation chamber 1, a sedimentation chamber 3, and a sludge chamber 5. Wastewater in the coagulation chamber 1 is transported to the bottom of the sedimentation chamber 3 via a conveying pipe 2. As the wastewater moves upward along the sedimentation chamber 3, the flocculated material settles downwards into the sedimentation chamber 3. The filtrate overflows from the top of the sedimentation chamber 3. The system also includes:

[0059] Inclined plate assembly 4, several inclined plate assemblies 4 are arranged in parallel inside the sedimentation tank 3, and the inclined plate assembly 4 includes a first filter plate 41 and a second filter plate 43.

[0060] The first filter plate 41 and the second filter plate 43 are arranged parallel to each other, and the angle between them and the horizontal plane is set at 40-50 degrees.

[0061] Specifically, based on the theory of shallow sedimentation, this system addresses the problem of weak sedimentation of calcium fluoride flocs in high-fluoride wastewater from fluorochemical industries. The angle between the inclined plate assembly 4 and the horizontal plane is designed to be 40-50 degrees, compared to the 55-60 degrees of existing technologies. This achieves two core sedimentation optimizations, directly resolving the technical bottlenecks of the original device, such as sedimentation efficiency reaching its limit and fluctuations in effluent fluoride concentration.

[0062] The effective sedimentation area of ​​the inclined plate is the horizontal projected area. The small angle of 40-50 degrees significantly increases the horizontal projected area of ​​a single inclined plate. Moreover, this angle range is within the high-efficiency range where the increase in projected area increases as the angle decreases. Several parallel inclined plate components 4 in the sedimentation tank 3 form a sedimentation space, which greatly increases the effective sedimentation area compared to the traditional design. The increase in effective sedimentation area directly reduces the wastewater treatment load per unit area, allowing the originally weak calcium fluoride flocs to have more time to contact the inclined plate and complete sedimentation, achieving efficient and deep separation of calcium fluoride flocs. This fundamentally improves the mud-water separation effect and ensures that the effluent fluoride concentration meets the standards.

[0063] In an embodiment of the present invention, the first filter plate 41 is fixedly installed in the sedimentation tank 3. The first filter plate 41 is provided with a material leakage port 411 and a flip cover 42 is provided inside the material leakage port 411. The second filter plate 43 and the first filter plate 41 are linked together and an elastic element is provided between them.

[0064] The setting of the discharge port 411 can significantly shorten the downward movement distance of the sediment on the first filter plate 41, allowing it to quickly detach from the plate body through the discharge port 411 and fall directionally to the second filter plate 43 below. However, the sediment on the second filter plate 43 still has the problem of strong adhesion and difficulty in detaching on its own. Therefore, external force can be used to squeeze the second filter plate 43 and the first filter plate 41 closer together. When the second filter plate 43 moves toward the first filter plate 41, it simultaneously forms a blockage in the upper area between the two plates, forcing the sewage mixed with sediment between the two plates to flow downward in a directional direction. With the help of hydraulic action and squeezing action, the sediment on the surface of the second filter plate 43 is cleaned. Moreover, since the initial distance between the two plates is small, the hydraulic disturbance of the sediment during the cleaning process is controllable. After the cleaning is completed, the elastic element can drive the two plates to return to the initial distance and restore the normal sedimentation function. During this process, the first filter plate 41 can proceed normally to meet the requirement of continuity.

[0065] In another embodiment of the present invention, a discharge assembly 6 is further included, which includes a drive unit and a transmission unit. The drive unit is disposed on the upper part of the inclined plate assembly 4, and the drive unit and the flip cover 42 are connected by the transmission unit. The drive unit includes a displacement plate 61, an unfolding plate 62, a guide groove 631, and a rotating column 63. The guide groove 631 is formed on the second filter plate 43. The displacement plate 61 is slidably connected to the top of the first filter plate 41. The unfolding plate 62 is slidably connected to the displacement plate 61. The rotating column 63 is rotatably connected to the unfolding plate 62, and the lower part of the rotating column 63 is rolled within the guide groove 631.

[0066] Specifically, when sediment cleaning is required, the displacement plate 61 is driven by an external drive source to slide along the top of the first filter plate 41. Since one end of the rotating column 63 is rotatably connected to the unfolding plate 62 and the other end is rolled into the guide groove 631 of the second filter plate 43, the horizontal movement of the unfolding plate 62 is achieved through the cooperation of the rotating column 63 and the guide groove 631. The rotating column 63 moves along the guide groove 631 to synchronously drive the unfolding plate 62 to unfold, thus achieving the sealing of the top of the first filter plate 41 and the second filter plate 43 until the rotating column 63 moves to the other end of the guide groove 631. At this time, the displacement plate 61 continues to move, and the pressure on the second filter plate 43 continues to increase, which will be converted into a force to drive the second filter plate 43 to move, so that the distance between the second filter plate 43 and the first filter plate 41 is reduced, realizing the compression adjustment of the distance between the two plates. After the driving force is removed, the reset force of the elastic element will cause the second filter plate 43 to return to the initial position.

[0067] The transmission unit includes a drive bar 64, a rotating shaft 66, a pin 641, and an annular groove 661. The drive bar 64 is slidably connected to the side of the first filter plate 41. The upper part of the drive bar 64 is set on the unfolding path of the unfolding plate 62. One end of the rotating shaft 66 is fixedly installed on the flip cover 42. The annular groove 661 is opened on the rotating shaft 66. The pin 641 is fixedly installed on the drive bar 64. The other end of the pin 641 is inserted into the annular groove 661.

[0068] Specifically, the transmission unit acts as the driving unit and is linked with the flip cover 42 to synchronously control the opening and closing of the discharge port 411. When the unfolding plate 62 unfolds horizontally, its movement path directly acts on the upper part of the driving bar 64, pushing the driving bar 64 to slide laterally along the side of the first filter plate 41. Since the pin 641 is fixed to the driving bar 64 and embedded in the annular groove 661 of the rotating shaft 66, the lateral movement of the driving bar 64 is converted into the rotational movement of the rotating shaft 66 through the sliding cooperation between the pin 641 and the arc-shaped annular groove 661. This, in turn, drives the flip cover 42, which is fixed to it, to rotate and close around the discharge port 411. In this way, a closed space with only a bottom opening is formed between the first filter plate 41 and the second filter plate 43. This ensures that during the squeezing and adjustment process, the sewage mixed with sediment between the two plates can only flow downwards in a directional direction. At the same time, it prevents the sediment from flowing back to the surface of the first filter plate 41 through the discharge port 411, reducing interference with the normal sedimentation function of the first filter plate 41.

[0069] When the unfolding plate 62 retracts and resets, the drive bar 64 loses its thrust and resets with the elastic element. The pin 641 moves in the opposite direction along the annular groove 661, driving the rotating shaft 66 to rotate in the opposite direction, which in turn opens the flip cover 42 to continue receiving sediment.

[0070] In this embodiment, the horizontal projected area is significantly increased. By sealing the top, closing the discharge port 411, and squeezing the space between the first filter plate 41 and the second filter plate 43, the top of the two plates is sealed by the unfolding plate 62, the discharge port 411 is closed by the flip cover 42, and the compression displacement of the second filter plate 43 is combined to enhance the downward directional flow of sewage between the two plates, improve the cleaning efficiency of sediment on the surface of the second filter plate 43, avoid the problem of sediment backflow, and ensure the continuous and stable operation of the equipment.

[0071] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A continuous process for the treatment of highly fluorinated waste water from fluorinated industry, characterized in that: The method comprises the following steps: Step 1: introducing high-fluorine-containing wastewater into a collecting tank with stirring device for homogenization, adding a regulator to adjust the pH to 8.0-9.0; after maintaining a stable residence time by adopting a continuous overflow design, entering the next link; Step 2: calcium fluoride precipitation: the adjusted wastewater is introduced into a reaction tank with stirring device, CaCl2 is added according to the molar ratio of fluorine to calcium ions of 2:1.05-2:1.2, and then stirring and mixing are performed to make F - react with Ca 2+ to generate CaF2 precipitation; Step 3: introducing the wastewater containing precipitates into a sludge-water separation system, adding PAC and PAM in sequence, then entering a Lamella precipitation device, starting a sludge backflow system, and backflowing part of CaF2 sludge as crystal seeds; Step 4: monitoring the fluorine concentration and pH of the effluent in real time, if the fluorine concentration exceeds the standard, returning the wastewater to the coagulation reaction section for reprocessing, and if the fluorine concentration meets the standard, directly discharging or entering a deep treatment process.

2. The process according to claim 1, characterized in that, In step 1, the regulator is sodium hydroxide solution or calcium hydroxide suspension, and the mass concentration of the regulator is 5%-10%.

3. The process according to claim 1, characterized in that, In step 3, the addition amount of PAC is 50-100 mg / L, the addition amount of PAM is 5-10 mg / L, and the interval time between the addition of PAC and PAM is 5-10 min.

4. The process according to claim 1, characterized in that, In step 3, the inclination angle of the inclined plate in the Lamella precipitation device is 40-50 degrees, and the residence time of the wastewater in the Lamella precipitation device is 40-60 min.

5. The process according to claim 1, wherein the process is characterized by, In step 4, the monitoring frequency of the online monitoring device is 1 time / 5-10 min, and the fluorine concentration exceeding the standard is determined when the fluorine concentration of the effluent is >5 mg / L.

6. A continuous treatment system for high fluorine-containing wastewater in fluorine chemical industry, which is used to implement the continuous treatment process for high fluorine-containing wastewater according to any one of claims 1-5, comprising a coagulation bin (1), a sedimentation bin (3) and a sludge bin (5), wherein the wastewater in the coagulation bin (1) is delivered to the bottom of the sedimentation bin (3) through a delivery pipe (2), the flocculation material in the wastewater moves upward along the sedimentation bin (3) and is precipitated downward to the sedimentation bin (3), and the filtrate overflows from the upper part of the sedimentation bin (3), characterized in that, Further comprising: A plurality of inclined plate assemblies (4) are arranged in parallel in the precipitation bin (3), and the inclined plate assembly (4) comprises a first filter plate (41) and a second filter plate (43). The first filter plate (41) and the second filter plate (43) are arranged in parallel and are arranged at an angle of 40-50 degrees with the horizontal plane.

7. The fluorinated industrial high-fluorine-content wastewater continuous treatment system according to claim 6, characterized in that, The first filter plate (41) is fixedly installed in the precipitation bin (3), a material leakage opening (411) is formed in the first filter plate (41), a turnover cover (42) is arranged in the material leakage opening (411), the second filter plate (43) and the first filter plate (41) are connected in linkage, and an elastic member is arranged between the second filter plate (43) and the first filter plate (41).

8. The fluorinated industrial high-fluorine-content wastewater continuous treatment system according to claim 7, characterized in that, Further comprising a discharging assembly (6) comprising a driving part and a transmission part, the driving part is arranged at the upper part of the inclined plate assembly (4), and the driving part and the turnover cover (42) are transmissionally connected through the transmission part.

9. The fluorinated industrial high-fluorine-content wastewater continuous treatment system according to claim 8, characterized in that, The driving part comprises a displacement plate (61), an unfolding plate (62), a guide groove (631), and a rotating column (63), the guide groove (631) is formed in the second filter plate (43), the displacement plate (61) is slidingly connected to the top of the first filter plate (41), the unfolding plate (62) is slidingly connected to the displacement plate (61), the rotating column (63) is rotationally connected to the unfolding plate (62), and the lower part of the rotating column (63) is rollingly connected in the guide groove (631).

10. The fluorinated industrial high-fluorine-content wastewater continuous treatment system according to claim 9, characterized in that, The transmission part comprises a driving strip (64), a rotating shaft (66), a pin column (641) and an annular groove (661), the driving strip (64) is slidingly connected to the side edge of the first filter plate (41), the upper part of the driving strip (64) is arranged on the unfolding path of the unfolding plate (62), one end of the rotating shaft (66) is fixedly installed on the turnover cover (42), the annular groove (661) is arranged on the rotating shaft (66), the pin column (641) is fixedly installed on the driving strip (64), and the other end of the pin column (641) is inserted into the annular groove (661).

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