A crystallizer protecting slag fluorine-containing wastewater purification treatment device

Abstract

The application provides a crystallizer protecting slag fluorine-containing wastewater purification treatment device, which comprises a pretreatment cylinder, a blockage prevention filter assembly is arranged in the pretreatment cylinder, an adjusting tank is installed at the bottom of the pretreatment cylinder, a first lifting pump is connected to the right side of the adjusting tank through a pipeline, the liquid outlet end of the first lifting pump is communicated with a neutralization tank through a pipeline, a second lifting pump is connected to the right side of the neutralization tank through a pipeline, the liquid outlet end of the second lifting pump is communicated with an induced crystallization reactor through a pipeline, the liquid outlet end of the right side of the induced crystallization reactor is connected with a coagulation tank through a pipeline, and the front end of the coagulation tank is connected with a flocculation tank through a pipeline. The induced crystallization + coagulation precipitation + filtration adsorption combined process is adopted, the defluorination effect is good, the effluent is superior to the discharge standard, high-purity calcium fluoride crystals are generated by induced crystallization, fluorine resources are recycled and reused, and the device is suitable for high-concentration fluorine-containing wastewater treatment in multiple industries such as steel continuous casting, fluorine chemical industry and electrolytic aluminum.

Description

Technical Field

[0001] This invention relates to the field of water pollution control and treatment technology, and in particular to a device for purifying and treating fluoride-containing wastewater from crystallizer protective residue. Background Technology

[0002] In the continuous casting process of steel, mold flux is used to isolate molten steel from air, lubricate the mold wall, and absorb inclusions in the molten steel. During its use, it is discharged with the secondary cooling water of the continuous casting process, forming fluoride-containing wastewater. This type of wastewater is characterized by large fluctuations in water quality and quantity, a wide range of fluoride concentrations, and unstable pH values. It also contains a large amount of suspended solids such as mold flux debris and iron oxide scale, as well as trace amounts of heavy metals.

[0003] Currently, the main methods for treating industrial fluoride-containing wastewater include single or simple combinations of processes such as lime precipitation, coagulation sedimentation, and adsorption. However, these methods have many shortcomings when treating fluoride-containing wastewater from crystallizer protective slag, making it difficult to meet the actual needs of industrial production. While lime precipitation is relatively inexpensive, the resulting calcium fluoride precipitate particles are small and have a high water content, easily leading to sludge bulking, high sludge production, and high subsequent disposal costs. Furthermore, its fluoride removal efficiency is limited, making it difficult to stably reduce the fluoride concentration to below 10 mg / L, thus failing to meet stringent discharge standards. Simple coagulation sedimentation can only remove some suspended solids and trace amounts of fluoride ions from wastewater, and its effect on high-concentration fluoride wastewater is poor, making it difficult to meet effluent fluoride concentration standards. Single adsorption methods are limited by adsorbent capacity, resulting in low treatment efficiency, frequent regeneration, and are unsuitable for large-scale continuous industrial production, and they cannot achieve the recovery and utilization of fluoride resources.

[0004] Therefore, given the characteristics of fluoride-containing wastewater from crystallizer protective slag, developing a purification treatment device that can achieve efficient fluoride removal, stable operation, and adaptability to continuous industrial production, and overcoming the shortcomings of existing technologies, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the above-mentioned background art, and to propose a device for purifying and treating fluoride-containing wastewater from crystallizer protective slag.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A device for purifying fluoride-containing wastewater from crystallizer protective residue includes a pretreatment cylinder. An anti-clogging filter assembly is installed inside the pretreatment cylinder. An equalization tank is installed at the bottom of the pretreatment cylinder. A first lift pump is connected to the right side of the equalization tank via a pipe. The discharge end of the first lift pump is connected to a neutralization tank via a pipe. A second lift pump is connected to the right side of the neutralization tank via a pipe. The discharge end of the second lift pump is connected to an induced crystallization reactor via a pipe. The discharge end of the crystallization reactor on the right side is connected to a coagulation tank via a pipe. The front end of the coagulation tank is connected to a flocculation tank via a pipe. The discharge end of the flocculation tank on the left side is connected to an inclined tube sedimentation tank via a pipe. The discharge end of the inclined tube sedimentation tank on the left side is connected to an intermediate water tank via a pipe. The discharge end of the intermediate water tank on the left side is connected to a quartz sand filter via a pipe. The discharge end at the bottom of the quartz sand filter is connected to a third lift pump via a pipe. The discharge end of the third lift pump is connected to an activated alumina defluorination tower via a pipe.

[0007] Preferably, the anti-clogging filter assembly consists of a middle cylinder, a return spring, a support column, a base plate, blades, a transmission column, a movable disc, a cleaning column, a limiting disc, a filter screen, a connecting column, and a scraper. The pretreatment cylinder has a middle cylinder body fixed to its lower interior by a bracket. A return spring and a support column are embedded inside the middle cylinder body. A base plate is nested on the top of the support column. Blades are fixed to the outer wall of the base plate. A transmission column is vertically fixed above the middle part of the base plate. A movable disc is nested above the outer wall of the base plate. A cleaning column is vertically fixed to the upper surface of the movable disc. A limit disc is fixed to the outer wall of the cleaning column. A filter screen is fixed to the upper interior of the middle cylinder body. A connecting column is vertically embedded in the middle of the filter screen. A scraper is fixed to the top outer wall of the connecting column.

[0008] Preferably, the top of the filter screen and the movable disc are arranged in a conical shape with a smaller top and a larger bottom, and a hollow annular slag storage tank is provided with an opening on the outer side of the upper surface of the filter screen. The number of cleaning columns above the movable disc is the same as the number of filter holes in the filter screen.

[0009] Preferably, the top of the cleaning column is embedded in the filter holes of the filter screen, the upper surface of the filter screen and the upper surface of the cleaning column are on the same horizontal plane, and the cross-sectional area of ​​the cleaning column and the cross-sectional area of ​​the filter holes are the same size.

[0010] Preferably, the bottom end of the scraper is in close contact with the upper surface of the filter screen, the transmission column is composed of a cylinder in the lower section and a pentagonal prism in the upper section, the pentagonal prism in the upper section of the transmission column is embedded in the lower part of the connecting column, and the outer wall of the upper section of the transmission column is in close contact with the inner wall of the connecting column.

[0011] Preferably, the outer wall of the movable disk has 10-50 inclined guide ports arranged in a circular shape around its center, and the blades are located at the bottom of the guide ports. The inclination direction of the guide ports is opposite to that of the blades. The outer wall of the movable disk is in close contact with the inner wall of the pretreatment cylinder.

[0012] Preferably, the wastewater stays in the equalization tank for 8 to 12 hours. The equalization tank is equipped with a submersible agitator, a level transmitter, and an online pH monitor. The induced crystallization reactor has a built-in cyclone distributor and a mechanical agitator. The side wall is provided with a calcium chloride dosing port, a seed crystal return port, and a sewage discharge port. The reaction supersaturation is controlled to be 1.2 to 1.5.

[0013] Preferably, both the quartz sand filter and the activated alumina defluorination tower adopt a top-down pressure filtration structure. Both the quartz sand filter and the activated alumina defluorination tower are equipped with a water distributor, a filter media layer and a bottom water collection cap to intercept trace suspended solids and perform deep defluorination.

[0014] Preferably, a dosing device is provided above the neutralization tank, the induced crystallization reactor, the coagulation tank, and the flocculation tank. The four dosing devices respectively add appropriate amounts of acid and alkali agents, calcium chloride, polyaluminum chloride, and polyacrylamide to the neutralization tank, the induced crystallization reactor, the coagulation tank, and the flocculation tank.

[0015] Preferably, the activated alumina defluorination tower is filled with activated alumina filter media with a particle size of 3-5 mm, the filter media layer height is 1.0-1.2 m, and aluminum sulfate is used for regeneration after saturation.

[0016] This invention provides a device for purifying and treating fluoride-containing wastewater from crystallizer protective residue, which has the following beneficial effects:

[0017] 1. This crystallizer protective slag fluoride wastewater purification and treatment device adopts a combination process of "induced crystallization + coagulation sedimentation + deep adsorption", which can reduce the fluoride ion concentration of the crystallizer protective slag fluoride wastewater. The fluoride removal is highly efficient and meets the standards stably. The high-purity calcium fluoride crystals generated by induced crystallization can be recycled and reused, realizing the recycling of fluoride resources, reducing the raw material cost of enterprises. It can treat fluoride wastewater from steel continuous casting, and can also be adapted to the treatment of fluoride wastewater from fluorochemical, electrolytic aluminum and other industries. It has strong practicality and good industrial application prospects.

[0018] 2. When wastewater enters the pretreatment cylinder, it naturally drips down through the filter screen. The filter screen further traps various solid impurities and suspended debris mixed in the wastewater. After the falling wastewater comes into contact with the movable disc, it flows out from the outer guide port through the movable disc and impacts the bottom blades. Driven by the water flow, the blades drive the base plate, transmission column, connecting column, and scraper to rotate synchronously. This causes the scraper, which is attached to the upper surface of the filter screen, to perform a circumferential scraping along the surface of the filter screen, promptly removing the trapped debris accumulated on the surface of the filter screen and preventing debris from accumulating on the filter screen. The cover seals the filter holes, preventing them from blocking the water flow of the filter screen and ensuring the continuous and smooth flow of wastewater. When the wastewater stops being supplied to the pretreatment cylinder, the return spring releases its elastic rebound force and resets, pushing the support column, base plate, movable plate, and cleaning column upward as a whole. During the upward movement, the cleaning column is embedded into the filter screen holes from bottom to top, pushing out the small debris stuck in the filter holes, thereby achieving automatic unblocking and cleaning of the filter screen holes. No manual disassembly and cleaning is required, and the filtration effect can be maintained for a long time. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of a partial front cross-section of the pretreatment cylinder structure in this invention; Figure 3 This is a partial structural diagram of the movable disc and filter screen in this invention; Figure 4 This is a schematic diagram showing the usage state of the filter screen in this invention; Figure 5 This is a partial structural diagram of the connecting column and filter screen in this invention; Figure 6 This is a schematic diagram of a partial structure of the movable disk in this invention; Figure 7 This is an exploded view of a portion of the structure of the middle cylinder and the chassis plate in this invention; Figure 8 This is a schematic diagram of the overall structure and process of the present invention.

[0020] Legend: Pretreatment cylinder 1, middle cylinder 101, return spring 102, support column 103, base plate 104, blade 105, transmission column 106, movable plate 107, cleaning column 108, limiting plate 109, filter screen 110, connecting column 111, scraper 112, equalization tank 2, first lift pump 3, neutralization tank 4, second lift pump 5, induced crystallization reactor 6, coagulation tank 7, flocculation tank 8, inclined tube sedimentation tank 9, intermediate water tank 10, quartz sand filter 11, third lift pump 12, activated alumina defluorination tower 13. Detailed Implementation

[0021] Example 1, referring to Figure 1-8A device for purifying fluoride-containing wastewater from crystallizer protective residue includes a pretreatment cylinder 1. An anti-clogging filter assembly is installed inside the pretreatment cylinder 1. An equalization tank 2 is installed at the bottom of the pretreatment cylinder 1. A first lift pump 3 is connected to the right side of the equalization tank 2 via a pipe. The discharge end of the first lift pump 3 is connected to a neutralization tank 4 via a pipe. A second lift pump 5 is connected to the right side of the neutralization tank 4 via a pipe. The discharge end of the second lift pump 5 is connected to an induced crystallization reactor 6 via a pipe. The discharge end of the crystallization reactor 6 on the right side is connected to a coagulation tank 7 via a pipe. The front end of the coagulation tank 7 is connected to a flocculation tank 8 via a pipe. The discharge end of the flocculation tank 8 on the left side is connected to an inclined tube sedimentation tank 9 via a pipe. The discharge end of the inclined tube sedimentation tank 9 on the left side is connected to an intermediate water tank 10 via a pipe. The discharge end of the intermediate water tank 10 on the left side is connected to a quartz sand filter 11 via a pipe. The discharge end at the bottom of the quartz sand filter 11 is connected to a third lift pump 12 via a pipe. The discharge end of the third lift pump 12 is connected to an activated alumina defluorination tower 13 via a pipe.

[0022] The wastewater stays in the equalization tank 2 for 8 to 12 hours. The equalization tank 2 is equipped with a submersible agitator, a level transmitter and an online pH monitor. The induced crystallization reactor 6 has a built-in cyclone distributor and a mechanical agitator. The side wall is equipped with a calcium chloride dosing port, a seed crystal return port and a sewage discharge port. The reaction supersaturation is controlled at 1.2 to 1.5. The equalization tank 2 is mainly used to receive the fluoride-containing wastewater from the crystallizer protective slag after pretreatment by the pretreatment tank 1, playing a role in balancing the water volume and homogenizing the water quality; it can buffer the wastewater flow fluctuations caused by the start-up and shutdown of continuous casting production and the change of steel grade, and stabilize the influent load of the subsequent treatment unit; at the same time, it homogenizes the fluoride concentration, pH value and suspended solids content of the wastewater, reducing the impact of water quality fluctuations on chemical dosing and induced crystallization reaction; it can also naturally settle fine protective slag fragments, iron oxide scale and other particulate impurities in the wastewater, initially equalize the water temperature, buffer acid and alkali fluctuations, and reduce the operating condition adjustment pressure of the subsequent neutralization tank and induced crystallization reactor; Both the quartz sand filter 11 and the activated alumina defluorination tower 13 adopt a top-down pressure filtration structure. Both the quartz sand filter 11 and the activated alumina defluorination tower 13 are equipped with a water distributor, a filter media layer and a bottom water collection filter cap to intercept trace suspended solids and deeply remove fluoride. The quartz sand filter 11 is installed between the inclined tube sedimentation tank 9 and the activated alumina defluorination tower 13. Its main functions are: to further intercept residual fine suspended solids, protective slag powder, fine flocs and colloidal impurities in the wastewater, and reduce the turbidity of the effluent; to intercept small particles to avoid clogging the pores of the activated alumina adsorption tower filter media, prevent the adsorption layer from caking and extend the service life of the activated alumina; and at the same time, to perform preliminary purification of the water quality, ensuring that the water entering the subsequent activated alumina defluorination tower 13 is clean and stable, and creating good influent conditions for deep adsorption and defluorination. Dosing devices are installed above the neutralization tank 4, the induced crystallization reactor 6, the coagulation tank 7 and the flocculation tank 8. The four dosing devices add appropriate amounts of acid and alkali agents, calcium chloride, polyaluminum chloride and polyacrylamide to the neutralization tank 4, the induced crystallization reactor 6, the coagulation tank 7 and the flocculation tank 8 respectively. Dilute sulfuric acid and sodium hydroxide, among other acid-base agents, are added to neutralization tank 4 to adjust the pH of the wastewater to 7.0–8.0, creating optimal acid-base conditions for subsequent calcium fluoride induced crystallization. Calcium chloride is added to induced crystallization reactor 6 to provide calcium ions to combine with fluoride ions in the wastewater and induce the formation of high-purity calcium fluoride crystals on the seed surface, achieving primary fluoride removal. Polyaluminum chloride is added to coagulation tank 7, where residual fine fluoride crystals, suspended solids, and colloidal particles are agglomerated into tiny flocs through charge neutralization and adsorption bridging. Polyacrylamide is added to flocculation tank 8 to further agglomerate and grow the tiny flocs into dense large flocs, facilitating efficient mud-water separation in inclined tube sedimentation tank 9. After being neutralized to pH 7.0–8.0, the wastewater enters the induced crystallization reactor 6. The reactor 6 is divided into a seed bed, a reaction zone, and a clarification zone from bottom to top. Calcium chloride is added to the reactor to provide calcium ions, while calcium fluoride seed crystals are added as crystallization nuclei, controlling the reaction supersaturation to 1.2–1.5. Fluoride and calcium ions in the wastewater directionally attach and grow on the seed crystal surface, continuously generating high-purity calcium fluoride crystals, achieving efficient solidification and removal of fluoride ions. Under the action of stirring and swirling water distribution, the reaction is uniformly mixed, and the crystals grow in an orderly manner and are not easily broken. Large calcium fluoride crystals settle to the bottom of the reactor and are periodically discharged, sent to subsequent crystal concentration, dehydration, and recycling. The clear water overflows from the top and enters the downstream coagulation and sedimentation unit to complete the main defluorination process. The activated alumina defluorination tower 13 is filled with activated alumina filter media with a particle size of 3-5 mm, and the filter media layer height is 1.0-1.2 m. After saturation, it is regenerated with aluminum sulfate. The activated alumina fluoride removal tower 13 utilizes the porous adsorption characteristics of activated alumina filter media to deeply adsorb residual fluoride ions in the upstream process effluent, stabilizing the fluoride ion concentration in the wastewater below 1 mg / L, while simultaneously intercepting trace amounts of fine suspended solids and colloidal impurities. After the filter media becomes saturated, it can be regenerated and recycled using aluminum sulfate, ensuring that the effluent quality meets the requirements for discharge standards and reuse in continuous casting production. Wastewater flows sequentially through pretreatment tank 1 (intercepting large particles), equalization tank 2 (homogenizing water quality and quantity), and initial sedimentation of impurities. It is then transported to neutralization tank 4 (pH neutralization) by first booster pump 3. Next, it is pumped into induced crystallization reactor 6 (controlling supersaturation to 1.2-1.5) by second booster pump 5, where fluoride ions and calcium ions generate high-purity calcium fluoride crystals on the seed surface. Subsequently, it enters coagulation tank 7 (forming large flocs), flocculation tank 8 (forming large flocs), and inclined tube sedimentation tank 9 (efficiently separating the fluoride-containing fine crystals, suspended solids, and floc mixture formed after coagulation and flocculation). The effluent flows into intermediate water tank 10 (buffering and stabilizing pressure). The wastewater in intermediate water tank 10 is then transported to quartz sand filter 11 (retaining fine impurities) by third booster pump 12 for filtration, and finally enters activated alumina defluorination tower 13 (deeply adsorbing fluoride ions) for defluorination adsorption treatment. The intermediate water tank 10 is located between the inclined tube sedimentation tank 9 and the quartz sand filter 11. It is mainly used to temporarily store the effluent from the sedimentation tank and balance the influent flow and water pressure of the subsequent filtration units. It plays a role in buffering and stabilizing pressure and homogenizing water quality, and provides a stable constant pressure water supply to the quartz sand filter 11 and the activated alumina defluorination tower 13 to avoid fluctuations in filtration flow rate caused by sudden changes in water flow. At the same time, it settles a small amount of fine flocs carried out with the effluent, reducing the load on the downstream filtration equipment and ensuring continuous and stable operation of the subsequent deep filtration and adsorption defluorination.

[0023] Example 2 differs from Example 1 in that, in this example, the anti-clogging filter assembly consists of a middle cylinder 101, a return spring 102, a support column 103, a base plate 104, blades 105, a transmission column 106, a movable disc 107, a cleaning column 108, a limiting disc 109, a filter screen 110, a connecting column 111, and a scraper 112. A middle cylinder 101 is fixed to the lower part of the pretreatment cylinder 1 by a bracket. A return spring 102 and a support column 103 are embedded inside the middle cylinder 101. A base plate 104 is nested on the top of the support column 103. A blade 105 is fixed on the outer wall of the base plate 104. A transmission column 106 is vertically fixed above the middle part of the base plate 104. A movable disc 107 is nested above the outer wall of the base plate 104. A cleaning column 108 is vertically fixed on the upper surface of the movable disc 107. A limit disc 109 is fixed on the outer wall of the cleaning column 108. A filter screen 110 is fixed to the upper part of the middle cylinder 101. A connecting column 111 is vertically embedded in the middle part of the filter screen 110. A scraper 112 is fixed on the top outer wall of the connecting column 111. The tops of the filter screen 110 and the movable disc 107 are arranged in a conical shape with a smaller top and a larger bottom. A hollow annular slag storage tank is provided with an opening on the outer side of the upper surface of the filter screen 110. The number of cleaning columns 108 above the movable disc 107 is the same as the number of filter holes in the filter screen 110. The conical filter screen 110 and the movable disc 107 facilitate the guidance of the filtered debris and wastewater. When the debris slides down the upper surface of the filter screen 110 due to gravity, it will enter the sludge storage tank for storage. When wastewater enters the pretreatment cylinder 1, gravity will sequentially push the cleaning column 108, the movable plate 107, the base plate 104, and the support column 103 downwards, causing the support column 103 to compress the return spring 102 inside the middle cylinder 101 and deform. After the wastewater stops entering the pretreatment cylinder 101, the return spring 102 releases its elastic rebound force and resets, pushing the support column 108, the base plate 104, the movable plate 107, and the cleaning column 108 upwards as a whole. During the upward movement, the cleaning column 108 is embedded into the filter holes of the filter screen 110 from bottom to top, pushing out the small debris stuck in the filter holes, thus realizing the automatic unclogging operation of the filter screen 110. The top of the cleaning column 108 is perfectly embedded in the filter holes of the filter screen 110. The upper surface of the filter screen 110 and the upper surface of the cleaning column 108 are on the same horizontal plane. The cross-sectional area of ​​the cleaning column 108 and the cross-sectional area of ​​the filter holes are the same size. The cleaning column 108, which moves from bottom to top, will be fully embedded inside the filter mesh 110, pushing out the small debris stuck in the filter mesh and preventing debris from remaining. The bottom end of the scraper 112 is in close contact with the upper surface of the filter screen 110. The transmission column 106 is composed of a cylinder in the lower section and a pentagonal prism in the upper section. The pentagonal prism in the upper section of the transmission column 106 is embedded in the lower part of the connecting column 111. The outer wall of the upper section of the transmission column 106 is in close contact with the inner wall of the connecting column 111. Since the scraper 112 is in close contact with the upper surface of the filter screen 110, the connecting column 111 will drive the scraper 112 to perform circumferential scraping along the surface of the filter screen 110 when rotating, so as to remove the trapped debris accumulated on the surface of the filter screen 110 in time, avoid the debris covering and blocking the filter holes and affecting the water permeability of the filter screen, and ensure that the wastewater filtration flow is continuous and smooth. During the up-and-down movement of the movable plate 107, the transmission column 106 above the chassis plate 104 moves up and down simultaneously. Since the upper part of the transmission column 106 is embedded inside the connecting column 111 and closely attached to the inner wall of the connecting column 111, the pentagonal prism at the upper end of the transmission column 106 moves up and down in the connecting column 111 at the same time. When the movable plate 107 is at any height, the chassis plate 104 can still drive the connecting column 111 to rotate normally through the transmission column 106. The outer wall of the movable disk 107 has 10-50 inclined guide ports arranged in a circular shape around its center. The blade 105 is located at the bottom of the guide port. The inclination direction of the guide port is opposite to that of the blade 105. The outer wall of the movable disk 107 is in close contact with the inner wall of the pretreatment cylinder 1. After the falling wastewater comes into contact with the movable plate 107, it will flow out from the outer guide port through the movable plate 107, so that the water after the guide is exactly impacted by the blades 105 located at the bottom. The blades 105 are driven by the water flow to drive the chassis plate 104, transmission column 106, connecting column 111 and scraper 112 to rotate synchronously. There is no need to add a transmission power component, saving power consumption and mechanical drive loss. The structure is simple and has high energy utilization.

[0024] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these should also be considered within the scope of protection of the present invention. These will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A device for purifying and treating fluoride-containing wastewater from crystallizer protective slag, comprising a pretreatment cylinder (1), characterized in that, The pretreatment cylinder (1) is equipped with an anti-clogging filter assembly, which consists of a middle cylinder (101), a return spring (102), a support column (103), a base plate (104), blades (105), a transmission column (106), a movable disc (107), a cleaning column (108), a limiting disc (109), a filter screen (110), a connecting column (111), and a scraper (112). The middle cylinder (101) is fixed to the lower part of the pretreatment cylinder (1) by a bracket, and the return spring (102) and support are embedded inside the middle cylinder (101). A support column (103) has a base plate (104) nested at its top. A blade (105) is fixed to the outer wall of the base plate (104). A transmission column (106) is vertically fixed above the middle of the base plate (104). A movable disc (107) is nested above the outer wall of the base plate (104). A cleaning column (108) is vertically fixed to the upper surface of the movable disc (107). A limit disc (109) is fixed to the outer wall of the cleaning column (108). A filter screen (110) is fixed above the interior of the middle cylinder (101). A connecting column (111) is vertically embedded in the middle of the pretreatment cylinder (1). A scraper (112) is fixed to the top outer wall of the connecting column (111). An equalization tank (2) is installed at the bottom of the pretreatment cylinder (1). A first lift pump (3) is connected to the right side of the equalization tank (2) through a pipe. The discharge end of the first lift pump (3) is connected to the neutralization tank (4) through a pipe. A second lift pump (5) is connected to the right side of the neutralization tank (4) through a pipe. The discharge end of the second lift pump (5) is connected to the induced crystallization reactor (6) through a pipe. The discharge end of the crystallization reactor (6) on the right side is connected to the crystallization reactor (6) through a pipe. A coagulation tank (7) is connected to the front end of the coagulation tank (7) via a pipe. A flocculation tank (8) is connected to the left side of the flocculation tank (8) via a pipe. An inclined tube sedimentation tank (9) is connected to the left side of the inclined tube sedimentation tank (9) via a pipe. An intermediate water tank (10) is connected to the left side of the intermediate water tank (10) via a pipe. A quartz sand filter (11) is connected to the left side of the intermediate water tank (10) via a pipe. A third lift pump (12) is connected to the bottom of the quartz sand filter (11) via a pipe. The discharge end of the third lift pump (12) is connected to an activated alumina defluorination tower (13) via a pipe.

2. The device for purifying and treating fluoride-containing wastewater from crystallizer protective slag according to claim 1, characterized in that, The top of the filter screen (110) and the movable disc (107) are arranged in a conical shape with a smaller top and a larger bottom. A hollow annular slag storage tank is provided on the outer side of the upper surface of the filter screen (110). The number of cleaning columns (108) above the movable disc (107) is the same as the number of filter holes in the filter screen (110).

3. The device for purifying and treating fluoride-containing wastewater from crystallizer protective slag according to claim 1, characterized in that, The top of the cleaning column (108) is embedded in the filter hole of the filter screen (110). The upper surface of the filter screen (110) and the upper surface of the cleaning column (108) are on the same horizontal plane. The cross-sectional area of ​​the cleaning column (108) and the filter hole are the same size.

4. The device for purifying and treating fluoride-containing wastewater from crystallizer protective slag according to claim 1, characterized in that, The bottom end of the scraper (112) is in close contact with the upper surface of the filter screen (110). The transmission column (106) is composed of a cylinder in the lower section and a pentagonal prism in the upper section. The pentagonal prism in the upper section of the transmission column (106) is embedded in the lower part of the connecting column (111). The outer wall of the upper section of the transmission column (106) is in close contact with the inner wall of the connecting column (111).

5. The device for purifying and treating fluoride-containing wastewater from crystallizer protective slag according to claim 1, characterized in that, The outer wall of the movable disc (107) is provided with 10-50 inclined guide ports in a circular shape with equal spacing around its center. The blade (105) is located at the bottom of the guide port. The inclined direction of the guide port is opposite to the inclined direction of the blade (105). The outer wall of the movable disc (107) is in close contact with the inner wall of the pretreatment cylinder (1).

6. The device for purifying and treating fluoride-containing wastewater from crystallizer protective slag according to claim 1, characterized in that, The wastewater stays in the equalization tank (2) for 8 to 12 hours. The equalization tank (2) is equipped with a submersible agitator, a level transmitter and an online pH monitor. The induced crystallization reactor (6) has a built-in vortex distributor and a mechanical agitator. The side wall is equipped with a calcium chloride dosing port, a seed crystal return port and a sewage discharge port. The reaction supersaturation is controlled to be 1.2 to 1.

5.

7. The device for purifying and treating fluoride-containing wastewater from crystallizer protective slag according to claim 1, characterized in that, Both the quartz sand filter (11) and the activated alumina defluorination tower (13) adopt a top-down pressure filtration structure. Both the quartz sand filter (11) and the activated alumina defluorination tower (13) are equipped with a water distributor, a filter media layer and a bottom water collection filter cap to intercept trace suspended solids and remove fluoride in depth.

8. The device for purifying and treating fluoride-containing wastewater from crystallizer protective slag according to claim 1, characterized in that, Dosing devices are provided above the neutralization tank (4), the induced crystallization reactor (6), the coagulation tank (7), and the flocculation tank (8). The four dosing devices respectively add appropriate amounts of acid and alkali agents, calcium chloride, polyaluminum chloride, and polyacrylamide to the neutralization tank (4), the induced crystallization reactor (6), the coagulation tank (7), and the flocculation tank (8).

9. The device for purifying and treating fluoride-containing wastewater from crystallizer protective slag according to claim 1, characterized in that, The activated alumina defluorination tower (13) is filled with activated alumina filter media with a particle size of 3-5 mm and a filter media layer height of 1.0-1.2 m. After saturation, it is regenerated with aluminum sulfate.

Images