Filling process and equipment based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus

Abstract

The present invention discloses a filling process and equipment based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus, which solves the problem that soluble fluorine and phosphorus elements in the filling body of the existing method cannot be effectively separated, the soluble fluorine and phosphorus elements leached out in excess of the standard under long-term immersion in groundwater, and are difficult to be directly used for filling. The filling process and equipment include a thickening body, a deep cone thickener, a thickening drive assembly, and an anti-pressure rake mechanism. The thickening body includes an equipment base, equipment legs, and an equipment frame. The deep cone thickener includes a deep cone thickening tank, a feeding port, an overflow weir, and a concentrated discharge port. The anti-pressure rake mechanism includes an upper rake seat, a lower rake seat, an adjustable rake seat, and a rake seat protection portion. The present invention is provided with an anti-pressure rake mechanism, and the technical means of the coordinated cooperation of the adjustable rake seat and the rake seat protection portion can ensure that the APAM flocculant is evenly mixed with the pretreated phosphogypsum slurry, thereby avoiding the "rake pressure" phenomenon caused by the rapid sedimentation of the phosphogypsum slurry, thereby preventing the problem of incomplete separation of soluble fluorine and phosphorus elements.

Description

Technical Field

[0001] The utility model belongs to the field of comprehensive utilization of solid waste and mine filling technology, and specifically relates to a filling process and equipment based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus. Background Art

[0002] Phosphogypsum, a major industrial solid waste generated during phosphate rock production, is difficult to effectively utilize due to its high pollution levels. Currently, the main technical solution involves using phosphogypsum as a filling aggregate, adding a certain amount of ordinary Portland cement, and mixing with water to form a cemented fill that meets the required strength for underground goaf remediation. This solution addresses the issues of phosphogypsum storage and goaf collapse to a certain extent, but phosphogypsum from the cemented fill that enters the goaf can cause serious groundwater contamination. Therefore, pre-treating phosphogypsum to reduce its harmful content and achieve the required fill strength remains a bottleneck in the phosphogypsum filling industry.

[0003] Chinese patent CN111377632A discloses a phosphogypsum treatment agent, a phosphogypsum treatment method, a method for preparing a phosphogypsum filling material, and a phosphogypsum filling material. The invention utilizes ammonium sulfate, solid waste fine powder, and other materials to prepare the phosphogypsum treatment agent, thereby achieving the desired detoxification of the phosphogypsum while maintaining strength requirements. Meanwhile, Chinese patent CN100476162C discloses a method for filling phosphogypsum into underground goafs to form a solidified filling body. Cement, fly ash, and phosphogypsum are mixed in specific proportions, and then sodium sulfate is added as an additive to create a filling slurry with enhanced strength. Regarding the aforementioned related art, the inventors believe that although phosphogypsum is pre-treated by mixing with cement, fly ash, and other materials to form a phosphogypsum filling body of a certain strength, the pre-treatment process is complex and consumes significant resources. Furthermore, existing methods fail to effectively separate the soluble fluorine and phosphorus elements within the filling body. Long-term immersion in groundwater results in leaching levels exceeding standards, posing a potential risk of groundwater pollution and making it difficult to use directly for filling. In response to the above problems, we proposed a filling process and equipment based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus. Summary of the Invention

[0004] The purpose of the present invention is to address the shortcomings of the existing technology and provide a filling process and equipment based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus, which solves the problem that the soluble fluorine and phosphorus elements in the filling body of the existing method cannot be effectively separated, the soluble fluorine and phosphorus elements leached in excessive amounts under long-term immersion in groundwater, there is a potential risk of groundwater environmental pollution, and it is difficult to use them directly for filling.

[0005] The present invention is achieved by a filling device based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus, comprising:

[0006] A thickening machine body, the thickening machine body comprising an equipment base, equipment legs, and an equipment frame, wherein a plurality of sets of equipment legs are fixedly mounted on the equipment base, and the equipment frame is fixedly mounted on the equipment base;

[0007] Deep cone thickener, which is fixedly installed in the equipment base, includes a deep cone thickener, a feeding port, an overflow weir, and a concentrated discharge port. The feeding port and the concentrated discharge port are respectively arranged at the upper and lower ends of the deep cone thickener. The overflow weir is opened on the outside of the feeding port, and the overflow weir is connected to the feeding port. A pretreatment feeding pipe is provided on the top of the feeding port, and the pretreatment feeding pipe is fixedly installed in the equipment frame.

[0008] A thickening drive assembly, wherein the thickening drive assembly is fixedly mounted on the equipment frame;

[0009] At least one anti-pressure rake mechanism, which is arranged in the deep cone thickening tank and is used to stir the material and prevent the concentrated material from being raked. The anti-pressure rake mechanism is connected to the thickening drive assembly;

[0010] Among them, the anti-pressure rake mechanism includes:

[0011] an upper harrow seat connected to the thickening drive assembly;

[0012] A lower harrow seat is arranged below the upper harrow seat, and the lower harrow seat is fixedly connected to the upper harrow seat via an oblique support rod;

[0013] an adjustable harrow seat, the adjustable harrow seat being disposed within the upper harrow seat, the adjustable harrow seat being used to evenly mix the materials, and

[0014] The harrow seat protection part is arranged between the upper harrow seat and the lower harrow seat, and the harrow seat protection part is connected to the adjustable harrow seat for protecting the adjustable harrow seat.

[0015] The thickening drive assembly comprises:

[0016] A drive motor, wherein the drive motor is fixedly installed in the equipment frame;

[0017] A drive transmission unit fixedly connected to the output shaft of the drive motor, the drive transmission unit being used to drive the anti-pressure rake mechanism;

[0018] The drive transmission unit includes:

[0019] A driving wheel, wherein the driving wheel is fixedly connected to the output shaft of the driving motor;

[0020] A driven rotor is arranged on one side of the driving rotor, the driven rotor is rotatably connected to the driving rotor via a conveyor belt, and the driven rotor is rotatably mounted in the equipment frame;

[0021] a hollow drive shaft fixedly connected to the driven runner, wherein the hollow drive shaft is fixedly connected to the upper rake seat;

[0022] An aeration coupling is rotatably sleeved on the outer wall of the hollow drive shaft, one side of the aeration coupling is fixedly connected to an air supply pipe, and the lower end of the hollow drive shaft is fixedly connected to at least one group of aeration pipes.

[0023] The adjustable harrow seat comprises:

[0024] at least one set of adjustable rakes;

[0025] A linkage toothed roller fixedly connected to the adjustable harrow frame, wherein the linkage toothed roller is rotatably mounted in the upper harrow seat;

[0026] A linkage gear seat is slidably mounted in the upper harrow seat, and both sides of the linkage gear seat are respectively engaged with the linkage gear rollers for transmission;

[0027] An anti-settling seat fixedly connected to the linkage gear seat.

[0028] The rake seat protection portion comprises:

[0029] A protection linkage groove is provided on the side wall of the adjustable rake frame, and a protection linkage block is slidably installed in the protection linkage groove;

[0030] An auxiliary movable frame fixedly connected to the protection linkage block, wherein the auxiliary movable frame is slidably embedded in the movable guide seat, and the movable guide seat is fixedly installed in the upper rake seat;

[0031] A telescopic limit rod is fixedly installed in the upper rake seat, and the telescopic rod of the telescopic limit rod is fixedly connected to the side wall of the auxiliary movable frame.

[0032] It also includes a scraping and gathering mechanism, which is used to discharge the high-concentration phosphogypsum slurry concentrated at the bottom of the deep cone thickening tank through the concentration outlet, and the scraping and gathering mechanism is fixedly connected to the lower end of the hollow drive shaft;

[0033] The scraper gathering mechanism comprises:

[0034] a scraper support seat, the scraper support seat being fixedly connected to the lower end of the hollow drive shaft;

[0035] At least one set of bottom scraper racks, which are fixedly mounted on a scraper support and are used to scrape off deposited materials at the bottom of the deep cone thickening tank;

[0036] The anti-clogging discharge part is installed in the bottom scraper frame and is used to gather solid particles deposited at the bottom of the deep cone thickening tank to the center.

[0037] The bottom scraper frame comprises:

[0038] An oblique support arm, wherein the oblique support arm is fixedly installed in the scraper support seat;

[0039] A side scraping arm fixedly mounted on the end of the oblique support arm, the side scraping arm being used to scrape adsorbed matter off the side wall of the deep cone thickening tank;

[0040] An auxiliary scraper arm fixedly connected to the side scraper arm, and the auxiliary scraper arm is also fixedly connected to the end of the scraper support seat;

[0041] at least one set of side scrapers, wherein the side scrapers are fixedly mounted on the side scraping arms;

[0042] At least one set of auxiliary scrapers, wherein the auxiliary scrapers are fixedly mounted on the auxiliary scraper arm.

[0043] The anti-blocking discharge part includes:

[0044] An anti-blocking linkage shaft, the anti-blocking linkage shaft being rotatably mounted on the side scraper arm;

[0045] A linkage gear, the linkage gear being fixedly mounted on the upper end of the anti-blocking linkage shaft;

[0046] A limiting gear ring, which is fixedly mounted on the inner wall of the deep cone thickening tank and meshes with the linkage gear for transmission;

[0047] A spiral spoiler strip is fixedly mounted on the lower end of the anti-clogging linkage shaft, and is used to assist in gathering solid particles at the bottom of the deep cone thickening tank.

[0048] On the other hand, the present invention also provides a filling process based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus, which comprises:

[0049] S10, fresh phosphogypsum produced by the phosphoric acid chemical plant is selected, its moisture content and pH value are measured, and the phosphogypsum is conveyed to an industrial mixing barrel via a belt conveyor;

[0050] S20, adding clean water to storage hopper A, then dissolving the flaky NaOH into a 0.1-0.25 mol / L solution and cooling it to room temperature to complete the preparation of the alkaline detergent, and then using an acid, alkali, and corrosion-resistant clean water pump to pump the low-concentration NaOH solution into the industrial mixing tank;

[0051] S30, phosphogypsum, low-concentration NaOH solution, and clean water are uniformly mixed in an industrial mixing barrel to prepare a phosphogypsum slurry with a mass concentration of 10-15%, and the slurry is piped over long distances to a deep cone thickener in a filling preparation station using turbulent flow technology;

[0052] S40, adding APAM flocculant and clean water to the storage hopper B, stirring until the APAM flocculant is fully dissolved to prepare an APAM solution with a mass fraction of 0.5‰, and then using a clean water pump to pump the APAM flocculant to a deep cone thickener. The deep cone thickener performs solid-liquid separation and sedimentation concentration on the low-concentration phosphogypsum. The supernatant at the top of the deep cone thickener is discharged to the fluorine and phosphorus recovery system through an overflow weir. The high-concentration phosphogypsum slurry concentrated at the bottom of the deep cone thickener is discharged to the phosphogypsum filling slurry preparation system;

[0053] S50, fluorine and phosphorus recovery system recovers fluorine and phosphorus;

[0054] S501, using ultrafiltration or nanofiltration membrane technology, removes fine suspended particles and dissolved fluorine and phosphorus in the supernatant of the deep cone thickener through a semi-permeable membrane;

[0055] S502, using cation exchange resin and anion exchange resin, the supernatant is passed through the cation exchange resin and anion exchange resin to exchange out cations such as calcium and magnesium in the solution, and F - and PO4 3- Anions are adsorbed on the resin;

[0056] S503, adding a precipitant to the supernatant to reduce the concentration of fluorine and phosphorus ions in the supernatant;

[0057] S504, through reverse osmosis treatment to ensure that the supernatant meets the standards for reuse water, using a semi-permeable membrane to separate water molecules from soluble impurities under high pressure;

[0058] S60: The high-concentration phosphogypsum slurry concentrated at the bottom of the deep cone thickener is transported to the filling preparation station, where its moisture content and pH value are tested. Clean water and cementitious materials are added and stirred evenly to obtain the required homogeneous cementitious filling slurry. The homogeneous filling slurry is then transported to the underground goaf via a filling industrial pump.

[0059] The method for solid-liquid separation and sedimentation concentration of low-concentration phosphogypsum by the deep cone thickener comprises:

[0060] S401, the APAM flocculant is pumped into the feed port via a clean water pump, and then the low-concentration phosphogypsum slurry is transported to the pretreatment feed pipe through a long-distance pipe. The drive motor is turned on, and the drive motor starts to drive the active impeller to rotate, and the active impeller drives the driven impeller and the hollow drive shaft to rotate, so that the hollow drive shaft drives the upper rake seat and the lower rake seat to rotate, thereby achieving stirring and mixing of the low-concentration phosphogypsum slurry and the APAM flocculant.

[0061] S402, when the low-concentration phosphogypsum slurry and APAM flocculant are mixed to produce sedimentation, and too many solid particles are precipitated to produce the "rake pressure" phenomenon, the settled solid particles press down the adjustable rake frame, driving the adjustable rake frame to rotate downward, and the adjustable rake frame drives the linkage tooth roller to rotate, and the linkage tooth roller drives the linkage tooth seat and the anti-sedimentation seat to move upward, so that the anti-sedimentation seat moves the settled solid particles upward, and the adjustable rake frame drives the protective linkage groove to swing when swinging, and the protective linkage groove drives the auxiliary movable frame to move along the movable guide seat, and the telescopic limit rod buffers and limits the auxiliary movable frame, so that the settled solid particles on the surface of the adjustable rake frame fall off and reset to the initial position.

[0062] S403, the rotation of the hollow drive shaft can drive the scraper support seat to rotate, so that the scraper support seat drives the oblique support arm, side scraping arm, and auxiliary scraping arm to rotate, thereby realizing the synchronous and rapid scraping of solid particles settled at the bottom of the deep cone thickening tank by the side scraping arm and the auxiliary scraping arm.

[0063] S404, when the scraper support seat drives the oblique support arm, side scraper arm and auxiliary scraper arm to rotate, the limit gear ring meshes with the linkage gear, so that the linkage gear drives the anti-blocking linkage shaft to rotate, and the anti-blocking linkage shaft drives the spiral spoiler belt to rotate, so that the spiral spoiler drives the solid particles at the edge of the deep cone thickening tank to gather to the central area, and the high-concentration phosphogypsum slurry after sedimentation and concentration is discharged to the phosphogypsum filling slurry preparation system.

[0064] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0065] In the present invention, an anti-pressure rake mechanism is provided, which consists of an upper rake seat, a lower rake seat, an adjustable rake seat, and a rake seat protection part. The technical means of the coordinated cooperation of the adjustable rake seat and the rake seat protection part can ensure that the APAM flocculant and the pretreated phosphogypsum slurry are evenly mixed, avoiding the "rake pressure" phenomenon caused by the rapid sedimentation of the phosphogypsum slurry, which in turn causes the problem of incomplete separation of soluble fluorine and phosphorus elements. At the same time, the adjustable rake seat can also change its own scraping angle when the "rake pressure" phenomenon occurs, reduce its own load, avoid damage to the adjustable rake seat, extend the service life of the adjustable rake seat, ensure that the soluble fluorine and phosphorus elements in the phosphogypsum slurry are separated and thoroughly stirred, which is beneficial to the combination of APAM flocculant and gypsum slurry to prepare a homogeneous filling slurry, and then transport the above-mentioned homogeneous filling slurry to the underground goaf through the filling industrial pump, thereby realizing the comprehensive utilization of phosphogypsum waste and the management of underground goaf. The method overcomes the problem that the soluble fluorine and phosphorus elements in the filling body cannot be effectively separated by the existing method, the soluble fluorine and phosphorus elements leached out in excess of the standard after long-term immersion in groundwater, there is a potential risk of groundwater environmental pollution, and it is difficult to use them directly for filling.

[0066] In the present invention, an adjustable rake seat is provided, and the adjustable rake seat is composed of an adjustable rake frame, a linkage tooth roller, a linkage tooth seat and an anti-settling seat. The swinging adjustable rake frame is linked with the anti-settling seat through the linkage tooth roller, the linkage tooth seat, so that the anti-settling seat can be synchronously driven to move back and forth up and down, which effectively reduces the "rake pressure" phenomenon and helps to evenly mix low-concentration phosphogypsum and APAM flocculant, which is beneficial to the recovery and treatment of fluorine and phosphorus in low-concentration phosphogypsum.

[0067] In the present invention, a scraper gathering mechanism is provided, which consists of a bottom scraper frame and an anti-clogging discharge part. The bottom scraper frame and the anti-clogging discharge part cooperate with each other to gather the solid sedimentation particles deposited at the bottom of the dense thickener to the center, preventing the material from accumulating at the bottom of the thickener, and at the same time quickly scraping off the material, thereby improving the solid-liquid separation and sedimentation concentration efficiency of low-concentration phosphogypsum.

[0068] The present invention provides a filling process based on pretreatment of phosphogypsum during pipeline transportation and recovery of fluorine and phosphorus. The phosphogypsum is used as a filling aggregate and subjected to alkaline washing pretreatment during long-distance pipeline transportation using turbulent flow technology. The phosphogypsum is then passed through a thickening device and stirred with a cementitious material to prepare a homogeneous filling slurry. At the same time, soluble fluorine and phosphorus elements and high-purity recycled water in the supernatant are recovered and utilized through membrane filtration, ion exchange, chemical precipitation and other technologies, thereby achieving the goals of reducing harmful substances in the phosphogypsum and reducing the harm of the filling slurry to groundwater. The homogeneous filling slurry is then transported to an underground goaf by a filling industrial pump, thereby achieving comprehensive utilization of phosphogypsum waste and management of underground goaf, reducing waste of land resources, preventing groundwater pollution, and contributing to environmental sustainability. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a structural schematic diagram of the filling equipment based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus provided by the present invention.

[0070] Figure 2 It is a structural schematic diagram of the filling equipment based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus provided by the present invention.

[0071] Figure 3 This is a front view of the filling equipment based on phosphogypsum pipeline pretreatment and fluorine and phosphorus recovery provided by the present invention.

[0072] Figure 4 yes Figure 3 AA section view.

[0073] Figure 5 It is a schematic diagram of the internal structure of the deep cone thickening tank provided by the present invention.

[0074] Figure 6 It is an internal axonometric view of the deep cone thickening tank provided by the present invention.

[0075] Figure 7 This is the internal main view of the deep cone thickening tank provided by the present invention.

[0076] Figure 8 It is an internal top view of the deep cone thickening tank provided by the present invention.

[0077] Figure 9 It is a structural schematic diagram of the anti-pressure rake mechanism provided by the present invention.

[0078] Figure 10 It is a three-dimensional structural schematic diagram of the anti-pressure rake mechanism provided by the present invention.

[0079] Figure 11 It is a front view of the anti-pressure rake mechanism provided by the present invention.

[0080] Figure 12 It is a side view of the anti-pressure rake mechanism provided by the present invention.

[0081] Figure 13 It is a structural schematic diagram of the scraper gathering mechanism provided by the present invention.

[0082] Figure 14 It is an axonometric diagram of the scraper gathering mechanism provided by the present invention.

[0083] Figure 15 It is a side view of the scraper gathering mechanism provided by the present invention.

[0084] Figure 16 It is a schematic diagram of the implementation process of the filling process based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus provided by the present invention.

[0085] In the figure: 1-thickening machine body, 11-equipment base, 12-equipment support legs, 13-equipment frame, 2-deep cone thickener, 21-deep cone thickening tank, 22-feeding port, 23-overflow weir, 24-concentration discharge port, 25-pretreatment feeding pipe, 26-air supply pipe, 3-thickening drive assembly, 31-drive motor, 32-drive transmission part, 321-driving wheel, 322-driven wheel, 323-conveyor belt, 324-hollow drive shaft, 325-aeration coupling, 4-anti-pressure rake mechanism, 41-upper rake seat, 42-lower rake seat, 43-oblique support rod, 44-adjustable rake seat, 441- Adjustable rake frame, 442-linked tooth roller, 443-linked tooth seat, 444-anti-settling seat, 45-rake seat protection part, 451-protection linkage groove, 452-auxiliary mobile frame, 453-telescopic limit rod, 454-movable guide seat, 46-aeration pipe, 5-scraper gathering mechanism, 51-scraper support seat, 52-bottom scraper frame, 521-oblique support arm, 522-side scraper arm, 523-auxiliary scraper arm, 524-side scraper, 525-auxiliary scraper, 53-anti-blocking discharge part, 531-linked gear, 532-limiting gear ring, 533-spiral spoiler belt, 534-anti-blocking linkage shaft. DETAILED DESCRIPTION

[0086] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0087] The existing methods cannot effectively separate the soluble fluorine and phosphorus elements in the filling body. The soluble fluorine and phosphorus elements leached out in excess of the standard after long-term immersion in groundwater, which poses a potential risk of groundwater pollution and is difficult to be used directly for filling. To address the above problems, we proposed a filling process and equipment based on pipeline pretreatment of phosphogypsum and fluorine and phosphorus recovery. In short, the equipment consists of a thickening body 1, a deep cone thickener 2, a thickening drive assembly 3, and at least one set of anti-pressure rake mechanisms 4. The thickening body 1 includes an equipment base 11, equipment legs 12, and an equipment frame 13. The deep cone thickener 2 includes a deep cone thickening tank 21, a feeding port 22, an overflow weir 23, and a concentrated discharge port 24. The anti-pressure rake mechanism 4 includes an upper rake seat 41, a lower rake seat 42, an adjustable rake seat 44, and a rake seat protection portion 45. In an embodiment of the present invention, an anti-pressure rake mechanism 4 is provided, which consists of an upper rake seat 41, a lower rake seat 42, an adjustable rake seat 44, and a rake seat protection portion 45. The technical means of the coordinated cooperation of the adjustable rake seat 44 and the rake seat protection portion 45 can ensure that the APAM flocculant and the pretreated phosphogypsum slurry are evenly mixed, avoiding the "rake pressure" phenomenon caused by the rapid sedimentation of the phosphogypsum slurry, which in turn causes the incomplete separation of soluble fluorine and phosphorus elements. At the same time, the adjustable rake seat 44 can also change its own scraping angle when the "rake pressure" phenomenon occurs, reduce its own load, avoid damage to the adjustable rake seat 44, extend the service life of the adjustable rake seat 44, ensure that the soluble fluorine and phosphorus elements in the phosphogypsum slurry are separated and thoroughly stirred, which is beneficial to the combination of APAM flocculant and gypsum slurry to prepare a homogeneous filling slurry, and then transport the above-mentioned homogeneous filling slurry to the underground goaf through the filling industrial pump, thereby realizing the comprehensive utilization of phosphogypsum waste and the management of underground goaf. The method overcomes the problem that the soluble fluorine and phosphorus elements in the filling body cannot be effectively separated by the existing method, the soluble fluorine and phosphorus elements leached out in excess of the standard after long-term immersion in groundwater, there is a potential risk of groundwater environmental pollution, and it is difficult to use them directly for filling.

[0088] The embodiment of the present invention provides a filling device based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus, such as Figures 1-4 As shown, the filling equipment based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus specifically includes:

[0089] The thickening machine body 1 includes an equipment base 11, equipment legs 12, and an equipment frame 13. A plurality of equipment legs 12 are fixedly mounted on the equipment base 11, and the equipment frame 13 is fixedly mounted on the equipment base 11.

[0090] It should be noted that the equipment base 11 is a rectangular or round base with a hollow interior, and the equipment legs 12 are circumferentially arranged below the equipment base 11. The tops of the equipment legs 12 are fixedly installed on the lower surface of the equipment base 11 by plugging and riveting, and the bottom of the equipment frame 13 is installed on the equipment base 11 by welding and bolting.

[0091] Deep cone thickener 2, deep cone thickener 2 is fixedly installed in the equipment base 11, deep cone thickener 2 includes a deep cone thickener tank 21, a feeding port 22, an overflow weir 23, and a concentrated material outlet 24, such as Figure 5-Figure 8 As shown, the feed port 22 and the concentration discharge port 24 are respectively arranged at the upper and lower ends of the deep cone thickening tank 21, the overflow weir 23 is opened on the outside of the feed port 22, and the overflow weir 23 is connected to the feed port 22, and a pretreatment feed pipe 25 is provided on the top of the feed port 22, and the pretreatment feed pipe 25 is fixedly installed in the equipment frame 13.

[0092] In an embodiment of the present invention, the deep cone thickener 2 is used to achieve solid-liquid separation and sedimentation concentration of low-concentration phosphogypsum, and fully separate the fluorine and phosphorus ions in the low-concentration phosphogypsum. The deep cone thickener 2 is a conical cylinder structure that is wide at the top and narrow at the bottom. The side wall of the deep cone thickener 2 is fixedly mounted on the equipment base 11 by welding or riveting, and the overflow weir 23 is a circular groove or annular groove structure. The overflow weir 23 is used to separate the low-concentration phosphogypsum supernatant that overflows after the thickening treatment, and a plurality of pretreatment feeding pipes 25 are provided on the top of the feeding port 22, and the pretreatment feeding pipes 25 are connected to the feeding end of the long-distance pipeline.

[0093] A thickening drive assembly 3, wherein the thickening drive assembly 3 is fixedly mounted on the equipment frame 13;

[0094] At least one set of anti-pressure rake mechanisms 4, which are arranged in the deep cone thickening tank 21 and are used to stir the material and prevent the concentrated material from being raked. The anti-pressure rake mechanisms 4 are connected to the thickening drive assembly 3;

[0095] Among them, such as Figures 9-12 As shown, the anti-pressure rake mechanism 4 includes:

[0096] An upper harrow seat 41 connected to the thickening drive assembly 3;

[0097] A lower harrow seat 42 is provided below the upper harrow seat 41, and the lower harrow seat 42 is fixedly connected to the upper harrow seat 41 via an oblique support rod 43;

[0098] An adjustable harrow seat 44 is provided in the upper harrow seat 41 and is used to evenly mix the materials, and

[0099] The harrow seat protection portion 45 is provided between the upper harrow seat 41 and the lower harrow seat 42 . The harrow seat protection portion 45 is connected to the adjustable harrow seat 44 for protecting the adjustable harrow seat 44 .

[0100] In this embodiment, the upper rake seat 41 and the lower rake seat 42 are rectangular seats with hollow interiors. The upper rake seat 41 and the lower rake seat 42 are used to scrape off high-concentration phosphogypsum slurry, and can stir and mix flocculants and low-concentration phosphogypsum, thereby improving the dense stirring efficiency of low-concentration phosphogypsum. The number of the inclined support rods 43 is 1-3 groups, and the upper and lower ends of the inclined support rods 43 are fixedly connected to the upper rake seat 41 and the lower rake seat 42 by plugging and welding.

[0101] In a further preferred embodiment of the present invention, Figure 1-Figure 2 As shown, the thickening drive assembly 3 includes:

[0102] A drive motor 31, wherein the drive motor 31 is fixedly installed in the equipment frame 13;

[0103] A driving transmission part 32 is fixedly connected to the output shaft of the driving motor 31 , and the driving transmission part 32 is used to drive the anti-pressure rake mechanism 4 .

[0104] In the embodiment of the present invention, the drive motor 31 is a servo motor, and the drive motor 31 is fixedly installed in the equipment frame 13 by clamps or rivets. The drive motor 31 is also electrically connected to a PLC controller, and the PLC controller is fixedly installed on the equipment base 11.

[0105] The driving transmission unit 32 includes:

[0106] A driving wheel 321, wherein the driving wheel 321 is fixedly connected to the output shaft of the driving motor 31;

[0107] A driven pulley 322 is provided on one side of the driving pulley 321. The driven pulley 322 is rotationally connected to the driving pulley 321 via a conveyor belt 323. The driven pulley 322 is rotationally installed in the equipment frame 13. The driving pulley 321 is fixedly connected to the output shaft of the drive motor 31 by plugging or riveting. The driven pulley 322 is rotationally connected to the equipment frame 13 via bearings or rollers.

[0108] A hollow drive shaft 324 fixedly connected to the driven runner 322, wherein the hollow drive shaft 324 is fixedly connected to the upper rake seat 41;

[0109] An aeration coupling 325 is rotatably sleeved on the outer wall of the hollow drive shaft 324, and an air supply pipe 26 is fixedly connected to one side of the aeration coupling 325. At least one group of aeration pipes 46 is fixedly connected to the lower end of the hollow drive shaft 324. One end of the air supply pipe 26 away from the aeration coupling 325 is fixedly connected to a blower, which is fixedly set on the side wall of the deep cone thickening tank 21, and the aeration pipe 46 is set between the upper rake seat 41 and the lower rake seat 42. A check valve is embedded in the aeration pipe 46.

[0110] In this embodiment, the interior of the hollow drive shaft 324 is hollow, so that the air can be guided when the air is blown into the air supply pipe 26, and the air is further blown into the adjustable rake seat 44, thereby avoiding the "rake pressure" phenomenon of the adjustable rake seat 44 and ensuring the normal use of the adjustable rake seat 44.

[0111] In a further preferred embodiment of the present invention, Figure 9-10 As shown, the adjustable rake seat 44 includes:

[0112] At least one set of adjustable rake frames 441, which are obliquely arranged on both sides of the upper rake seat 41, and the adjustable rake frames 441 are hollow seats, rectangular plates, curved plates or fan-shaped plates, and the surfaces of the adjustable rake frames 441 are polished;

[0113] A linkage toothed roller 442 fixedly connected to the adjustable harrow frame 441, wherein the linkage toothed roller 442 is rotatably mounted in the upper harrow seat 41, the linkage toothed roller 442 being rotatably connected to the upper harrow seat 41 via bearings or rollers, and the adjustable harrow frame 441 being fixedly connected to the linkage toothed roller 442 by welding or riveting;

[0114] A linkage gear seat 443 is slidably mounted in the upper harrow seat 41, and two sides of the linkage gear seat 443 are respectively engaged with the linkage gear roller 442 for transmission;

[0115] The anti-settling seat 444 is fixedly connected to the linkage gear seat 443.

[0116] In this embodiment, two groups of vertical racks are symmetrically arranged on both sides of the linkage gear seat 443. Each group of vertical racks engages and transmits the corresponding linkage gear roller 442 respectively. The anti-sinking seat 444 and the linkage gear seat 443 are fixedly connected by plugging or riveting.

[0117] In an embodiment of the present invention, an adjustable rake seat 44 is provided, and the adjustable rake seat 44 is composed of an adjustable rake frame 441, a linkage tooth roller 442, a linkage tooth seat 443 and an anti-settling seat 444. The swinging adjustable rake frame 441 is linked with the anti-settling seat 444 through the linkage tooth roller 442 and the linkage tooth seat 443, so that the anti-settling seat 444 can be synchronously driven to move back and forth up and down, which effectively reduces the "rake pressure" phenomenon and helps to evenly mix the low-concentration phosphogypsum and the APAM flocculant, which is beneficial to the recovery and treatment of fluorine and phosphorus in the low-concentration phosphogypsum.

[0118] In a further preferred embodiment of the present invention, Figure 1-2 As shown, the rake seat protection portion 45 includes:

[0119] A protection linkage slot 451 is provided on the side wall of the adjustable rake frame 441 , and a protection linkage block is slidably installed in the protection linkage slot 451 ;

[0120] The protection linkage groove 451 is opened on one side of the adjustable rake frame 441, and the protection linkage groove 451 is a rectangular groove or an arc groove with a polished inner wall. The protection linkage block is a spherical block or a cylindrical block, and the protection linkage block is plugged or riveted to the auxiliary movable frame 452.

[0121] An auxiliary movable frame 452 fixedly connected to the protective linkage block, wherein the auxiliary movable frame 452 is slidably embedded in a movable guide seat 454, and the movable guide seat 454 is fixedly installed in the upper rake seat 41;

[0122] The telescopic limiting rod 453 is fixedly installed in the upper rake seat 41 , and the telescopic rod of the telescopic limiting rod 453 is fixedly connected to the side wall of the auxiliary movable frame 452 .

[0123] In this embodiment, the auxiliary movable frame 452 is a rectangular frame, a "T"-shaped frame or an "L"-shaped frame structure. The auxiliary movable frame 452 is slidingly connected to the movable guide seat 454 through a slide rail or a slide groove. The movable guide seat 454 is fixedly connected to the upper rake seat 41 by welding or riveting. The telescopic limit rod 453 is a spring telescopic rod or a hydraulic telescopic rod.

[0124] During operation, the APAM flocculant is pumped into the feed port 22 via a clean water pump, and then the low-concentration phosphogypsum slurry is transported to the pretreatment feed pipe 25 via a long-distance pipe. The drive motor 31 is turned on, and the drive motor 31 starts to drive the active runner 321 to rotate, and the active runner 321 drives the driven runner 322 and the hollow drive shaft 324 to rotate, so that the hollow drive shaft 324 drives the upper rake seat 41 and the lower rake seat 42 to rotate, thereby achieving stirring and mixing of the low-concentration phosphogypsum slurry and the APAM flocculant. When the low-concentration phosphogypsum slurry and the APAM flocculant are mixed and settled, and too many solid particles are precipitated to produce a "rake pressure" phenomenon, the settled solid particles press down the adjustable rake frame 441, driving the adjustable rake frame 441 to move. Rotating downward, the adjustable rake frame 441 drives the linkage tooth roller 442 to rotate, and the linkage tooth roller 442 drives the linkage tooth seat 443 and the anti-sedimentation seat 444 to move upward, so that the anti-sedimentation seat 444 pushes the settled solid particles upward to avoid the settled solid particles settling too quickly, which leads to insufficient mixing of low-concentration phosphogypsum slurry and APAM flocculant. When the adjustable rake frame 441 swings, it drives the protective linkage groove 451 to swing, and the protective linkage groove 451 drives the auxiliary movable frame 452 to move along the movable guide seat 454. The telescopic limit rod 453 buffers and limits the auxiliary movable frame 452, so that the settled solid particles on the surface of the adjustable rake frame 441 fall off and reset to the initial position, avoiding damage to the adjustable rake frame 441.

[0125] In a further preferred embodiment of the present invention, Figure 5-Figure 6As shown, the embodiment of the present invention also includes a scraper and gathering mechanism 5, which is used to discharge the high-concentration phosphogypsum slurry concentrated at the bottom of the deep cone thickening tank 21 through the concentration discharge port 24. The scraper and gathering mechanism 5 is fixedly connected to the lower end of the hollow drive shaft 324.

[0126] In an embodiment of the present invention, a scraper gathering mechanism 5 is provided, which consists of a bottom scraper frame 52 and an anti-clogging discharge portion 53. The bottom scraper frame 52 and the anti-clogging discharge portion 53 cooperate to gather the solid sedimentation particles deposited at the bottom of the dense thickener to the center, prevent the material from accumulating at the bottom of the thickener, and quickly scrape off the material at the same time, thereby improving the solid-liquid separation and sedimentation concentration efficiency of low-concentration phosphogypsum.

[0127] The scraper gathering mechanism 5 includes:

[0128] The scraper support seat 51 is fixedly connected to the lower end of the hollow drive shaft 324, and the scraper support seat 51 and the hollow drive shaft 324 are welded or riveted;

[0129] At least one set of bottom scraper racks 52, the bottom scraper racks 52 are fixedly mounted on the scraper support 51, and the bottom scraper racks 52 are used to scrape the deposited materials at the bottom of the deep cone thickening tank 21;

[0130] The anti-clogging discharge portion 53 is installed in the bottom scraper frame 52 and is used to gather solid particles deposited at the bottom of the deep cone thickening tank 21 toward the center.

[0131] In a further preferred embodiment of the present invention, Figure 13-15 As shown, the bottom scraper frame 52 includes:

[0132] An oblique support arm 521 , the oblique support arm 521 being fixedly mounted in the scraper support seat 51 ;

[0133] A side scraping arm 522 fixedly mounted on the end of the oblique support arm 521, the side scraping arm 522 being used to scrape adsorbed matter off the side wall of the deep cone thickening tank 21;

[0134] The auxiliary scraping arm 523 is fixedly connected to the side scraping arm 522 , and the auxiliary scraping arm 523 is also fixedly connected to the end of the scraping material supporting seat 51 .

[0135] At least one set of side scrapers 524 , wherein the side scrapers 524 are fixedly mounted on the side scraping arms 522 ;

[0136] At least one set of auxiliary scrapers 525 , wherein the auxiliary scrapers 525 are fixedly mounted on the auxiliary scraping arm 523 .

[0137] It should be noted that the number of inclined support arms 521 is 3-6 groups, one end of the inclined support arm 521 is fixedly installed in the scraper support seat 51 by welding or plugging, the end of the inclined support arm 521 away from the scraper support seat 51 is welded to the side scraper arm 522, and the two ends of the auxiliary scraper arm 523 are bolted or welded to the side scraper arm 522 and the scraper support seat 51 respectively, the side scraper 524 and the auxiliary scraper 525 are respectively arranged in a matrix and linear on the side scraper arm 522 and the auxiliary scraper arm 523, and the side scraper 524 and the auxiliary scraper 525 are conical, sheet-like, and arc-shaped structures.

[0138] In this embodiment, the anti-clogging discharge portion 53 includes:

[0139] An anti-clogging linkage shaft 534 rotatably mounted on the side scraping arm 522 ;

[0140] A linkage gear 531 , the linkage gear 531 being fixedly mounted on the upper end of the anti-blocking linkage shaft 534 ;

[0141] A limiting gear ring 532 , which is fixedly mounted on the inner wall of the deep cone thickening tank 21 and meshes with the linkage gear 531 for transmission;

[0142] The spiral spoiler 533 is fixedly mounted on the lower end of the anti-clogging linkage shaft 534 , and is used to assist in gathering solid particles at the bottom of the deep cone thickening tank 21 .

[0143] In this embodiment, the middle portion of the anti-clogging linkage shaft 534 is rotatably connected to the side scraper arm 522 via a bearing or roller. The top portion of the anti-clogging linkage shaft 534 is fixedly connected to the linkage gear 531 by splicing or riveting. The linkage gear 531 is a bevel gear with a half, one-third, or one-quarter diameter. The limiting ring gear 532 is welded or riveted to the inner wall of the deep-cone thickening tank 21. The limiting ring gear 532 is a bevel gear. The spiral spoiler 533 is a conical spiral belt structure. The spiral spoiler 533 can be rotated by the linkage gear 531, thereby driving solid particles at the edge of the deep-cone thickening tank 21 to the center, facilitating the solid-liquid separation and sedimentation concentration of low-concentration phosphogypsum.

[0144] During operation, the rotation of the hollow drive shaft 324 can drive the scraper support seat 51 to rotate, so that the scraper support seat 51 drives the inclined support arm 521, the side scraping arm 522, and the auxiliary scraping arm 523 to rotate, thereby realizing the side scraping arm 522 and the auxiliary scraping arm 523 to synchronously and quickly scrape off the solid particles settled at the bottom of the deep cone thickening tank 21.

[0145] When the scraper support seat 51 drives the oblique support arm 521, the side scraping arm 522, and the auxiliary scraping arm 523 to rotate, the limiting gear ring 532 meshes with the linkage gear 531, so that the linkage gear 531 drives the anti-blocking linkage shaft 534 to rotate, and the anti-blocking linkage shaft 534 drives the spiral spoiler belt 533 to rotate, so that the spiral spoiler belt 533 moves the solid particles at the edge of the deep cone thickening tank 21 to the central area, and the high-concentration phosphogypsum slurry after sedimentation and concentration is discharged to the phosphogypsum filling slurry preparation system.

[0146] On the other hand, the embodiment of the present invention also provides a filling process based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus, such as Figure 16 As shown, the filling process based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus specifically includes:

[0147] S10, fresh phosphogypsum produced by the phosphoric acid chemical plant is selected, its moisture content and pH value are measured, and the phosphogypsum is conveyed to an industrial mixing barrel via a belt conveyor;

[0148] In this embodiment, the pH value of phosphogypsum is 2-4; the moisture content is 27%; and the main chemical components include: SO3, CaO and SiO2.

[0149] S20, adding clean water to storage hopper A, then dissolving the flaky NaOH into a 0.1-0.25 mol / L solution and cooling it to room temperature to complete the preparation of the alkaline detergent, and then using an acid, alkali, and corrosion-resistant clean water pump to pump the low-concentration NaOH solution into the industrial mixing tank;

[0150] It should be noted that the amount of the flaky NaOH is 15%-20% of the total mass of the phosphogypsum; the reaction temperature is 21-25° C., and the cooling time is 10 minutes.

[0151] S30, phosphogypsum, low-concentration NaOH solution, and clean water are uniformly mixed in an industrial mixing barrel to prepare a phosphogypsum slurry with a mass concentration of 10-15%, and the slurry is piped over a long distance to a deep cone thickener 2 in a filling preparation station using turbulent flow technology;

[0152] It should be noted that when long-distance pipeline transportation is selected, the Rayleigh number is set between 2000 and 4000 by adjusting factors such as pipeline diameter, homogeneous phosphogypsum concentration and density. At this time, the homogeneous phosphogypsum is in a turbulent state. The Rayleigh number is calculated using the following formula:

[0153]

[0154] Where:

[0155] ρ: Slurry density (kg / m 3 ), calculated according to formula (1);

[0156] μ: Slurry dynamic viscosity (Pa·s or N·s / m 2 ), calculated according to formula (2);

[0157] L: pipe diameter (m);

[0158] V: Slurry conveying speed (m 2 / s), calculated according to formula (3);

[0159] The slurry density is calculated using the following formula:

[0160]

[0161] Where:

[0162] ρ: Slurry density (kg / m 3 );

[0163] ρc: Density of sodium hydroxide solution (kg / m 3 );

[0164] ρa: density of phosphogypsum (kg / m 3 );

[0165] N: mass ratio of phosphogypsum to sodium hydroxide;

[0166] C: slurry mass concentration (%);

[0167] The dynamic viscosity of the slurry is calculated using the following formula:

[0168] μ=μ0×[1+a×(1-C)+b×(1-C) 2 ] (2)

[0169] Where:

[0170] μ: Slurry dynamic viscosity (Pa·s or N·s / m 2 );

[0171] μ0: viscosity of sodium hydroxide solution;

[0172] a, b: Empirical coefficients related to phosphogypsum particle characteristics and slurry composition; based on experimental measurements, they reflect the shape and size distribution of phosphogypsum particles and the overall rheological properties of the slurry;

[0173] C: slurry mass concentration (%);

[0174] The slurry delivery rate is calculated using the following formula:

[0175]

[0176] Where:

[0177] V: Slurry conveying speed (m2 / s);

[0178] K: empirical coefficient, which is related to slurry properties and pipeline layout; it is derived from actual working conditions and experimental data and usually requires calibration through experiments or known conditions;

[0179] L: pipe diameter (m);

[0180] μ: Slurry dynamic viscosity (Pa·s or N·s / m 2 );

[0181] C: slurry mass concentration (%).

[0182] It should be noted that the long-distance pipeline transportation time is determined by the distance between the phosphating plant and the filling preparation station, and is generally not less than 30 minutes.

[0183] S40, adding APAM flocculant and clean water to the storage hopper B, stirring until the APAM flocculant is fully dissolved to prepare an APAM solution with a mass fraction of 0.5‰, and then using a clean water pump to pump the APAM flocculant to the deep cone thickener 2. The deep cone thickener 2 performs solid-liquid separation and sedimentation concentration on the low-concentration phosphogypsum. The supernatant at the top of the deep cone thickener 2 is discharged to the fluorine and phosphorus recovery system through the overflow weir 23. The high-concentration phosphogypsum slurry after concentration at the bottom of the deep cone thickener 2 is discharged to the phosphogypsum filling slurry preparation system;

[0184] S50, fluorine and phosphorus recovery system recovers fluorine and phosphorus;

[0185] S501, using ultrafiltration or nanofiltration membrane technology to remove fine suspended particles and dissolved fluorine and phosphorus in the supernatant of deep cone thickener 2 through a semi-permeable membrane;

[0186] It should be noted that the principle of using ultrafiltration or nanofiltration membrane technology to remove fine suspended particles and dissolved fluorine and phosphorus elements in the supernatant of deep cone thickener 2 is to use ultrafiltration (UF) or nanofiltration (NF) membrane technology to separate water and small molecular solutes from large molecules or suspended particles through a semi-permeable membrane. Among them, ultrafiltration can intercept suspended matter and colloids with a particle size of 0.01-0.1 microns. Nanofiltration can intercept dissolved organic matter and some inorganic salts (including fluorine and phosphorus ions) with a particle size of 1-10 nanometers.

[0187] S502, using cation exchange resin and anion exchange resin, the supernatant is passed through the cation exchange resin and anion exchange resin to exchange out cations such as calcium and magnesium in the solution, and F - and PO4 3- Anions are adsorbed on the resin;

[0188] S503, adding a precipitant to the supernatant to reduce the concentration of fluorine and phosphorus ions in the supernatant;

[0189] It should be noted that the precipitant can be calcium hydroxide or calcium chloride, which generates a precipitate that is insoluble in water through a chemical reaction:

[0190] Calcium fluoride (CaF2): Ca 2+ +2F - →CaF2↓

[0191] Calcium phosphate (Ca3(PO4)2): 3Ca 2+ +2PO4 3- →Ca3(PO4)2↓

[0192] After the precipitate is formed, it is removed by filtration or centrifugation and the supernatant is further purified.

[0193] S504, through reverse osmosis treatment to ensure that the supernatant meets the standards for reuse water, using a semi-permeable membrane to separate water molecules from soluble impurities under high pressure;

[0194] Reverse osmosis can effectively remove dissolved fluoride, phosphorus ions and other trace impurities, producing high-purity recycled water.

[0195] As a result, through this multi-stage treatment process, the fluorine and phosphorus concentrations in the supernatant can be reduced to below national emission standards, ensuring no secondary pollution to the environment. Furthermore, the high-purity recycled water produced by reverse osmosis can be recycled back into the production process, significantly reducing fresh water consumption. Furthermore, the calcium fluoride in the precipitate can be recycled as a chemical raw material for use in industries such as fluorine chemicals, ceramics, and metallurgy. The calcium phosphate in the precipitate can be used as a raw material for phosphate fertilizer in agricultural production, thus reusing phosphorus resources.

[0196] S60: The high-concentration phosphogypsum slurry concentrated at the bottom of the deep cone thickener 2 is transported to the filling preparation station, where its moisture content and pH value are tested. Clean water and cementitious materials are added and stirred evenly to obtain the desired homogeneous cementitious filling slurry. The homogeneous filling slurry is then transported to the underground goaf via a filling industrial pump.

[0197] It should be noted that after testing the moisture content of high-concentration phosphogypsum slurry, it is composed of a certain mass fraction: 20 parts of phosphogypsum and 4 parts of cement. After adding clean water and stirring evenly, it is molded. The mass concentration is 63% and the density is 2.4g / cm 3 The test blocks were tested 3 days, 7 days and 28 days after demoulding, and 3 blocks were taken at each age. The average value was taken as the compressive strength of the filling body at that age.

[0198] According to the “Toxicity leaching method for solid waste by reversal method” (GB5086.1-1997), the broken test blocks after 28-day compressive strength test were processed to obtain leachate, and then the fluoride leaching amount of 28-day phosphogypsum filling was measured according to the “Determination of fluoride in water by ion-selective electrode method” (GB / T7484-1987).

[0199] Comparative Example 1

[0200] According to the steps described in Example 1, the amount of NaOH is 18% of the total mass of phosphogypsum, and the other steps remain unchanged. The mass composition of the filling slurry is: 20 parts of phosphogypsum, 4 parts of cement, and clean water is added to form a homogeneous filling slurry with a mass concentration of 63% and a density of 2.4g / cm 3 .

[0201] Comparative Example 2

[0202] According to the steps described in Example 1, the amount of NaOH is 20% of the total mass of phosphogypsum, and the mass composition of the filling slurry is: 20 parts of phosphogypsum, 4 parts of cement, and clean water is added to form a homogeneous filling slurry with a mass concentration of 63% and a density of 2.4g / cm 3 .

[0203] Comparative Example 3

[0204] According to the steps described in Example 1, without adding NaOH for pretreatment, the other steps remain unchanged, and the mass composition of the filling slurry is: 20 parts of phosphogypsum, 4 parts of cement, and clean water is added to form a homogeneous filling slurry with a mass concentration of 63% and a density of 2.4g / cm 3 .

[0205] The samples in the comparative examples and embodiments were subjected to compressive strength tests at different ages and fluorine leaching statistics at 28 days. The results are as follows:

[0206]

[0207] As can be seen from the above table, by comparing the examples with the comparative examples, it is found that after the phosphogypsum in the filling body is pretreated with NaOH, the strength of each age group increases, and the fluorine leaching amount decreases significantly. It can be found from Example 1 that the strength of the filling body after 28 days meets the mine filling requirements, indicating that the use of long-distance pipeline pretreatment plays a positive role in increasing the strength of the filling body.

[0208] In an embodiment of the present invention, a filling process based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus is provided. Phosphogypsum is used as a filling aggregate, and turbulent flow technology is used to perform alkaline washing pretreatment during long-distance pipeline transportation. The phosphogypsum is then mixed with a cementitious material after passing through a thickening device to prepare a homogeneous filling slurry. At the same time, soluble fluorine and phosphorus elements and high-purity recycled water in the supernatant are recycled and utilized through membrane filtration, ion exchange, chemical precipitation and other technologies, thereby achieving the goals of reducing harmful substances in phosphogypsum and reducing the harm of the filling slurry to groundwater. The above-mentioned homogeneous filling slurry is then transported to the underground goaf through a filling industrial pump, thereby realizing the comprehensive utilization of phosphogypsum waste and the management of the underground goaf, which can reduce the waste of land resources, prevent groundwater resource pollution, and contribute to environmental sustainability.

[0209] The embodiment of the present invention further provides a method for solid-liquid separation and sedimentation concentration of low-concentration phosphogypsum using a deep cone thickener 2. The method for solid-liquid separation and sedimentation concentration of low-concentration phosphogypsum using a deep cone thickener 2 specifically includes:

[0210] S401, the APAM flocculant is pumped into the feeding port 22 via a clean water pump, and then the low-concentration phosphogypsum slurry is transported to the pretreatment feeding pipe 25 via a long-distance pipe, and the drive motor 31 is turned on. The drive motor 31 starts to drive the active rotor 321 to rotate, and the active rotor 321 drives the driven rotor 322 and the hollow drive shaft 324 to rotate, so that the hollow drive shaft 324 drives the upper rake seat 41 and the lower rake seat 42 to rotate, thereby achieving stirring and mixing of the low-concentration phosphogypsum slurry and the APAM flocculant.

[0211] S402, when the low-concentration phosphogypsum slurry and APAM flocculant are mixed to produce sedimentation, and too many solid particles are precipitated to produce a "rake pressure" phenomenon, the settled solid particles press down the adjustable rake frame 441, driving the adjustable rake frame 441 to rotate downward, and the adjustable rake frame 441 drives the linkage tooth roller 442 to rotate, and the linkage tooth roller 442 drives the linkage tooth seat 443 and the anti-sedimentation seat 444 to move upward, so that the anti-sedimentation seat 444 moves the settled solid particles upward, and when the adjustable rake frame 441 swings, it drives the protective linkage groove 451 to swing, and the protective linkage groove 451 drives the auxiliary movable frame 452 to move along the movable guide seat 454, and the telescopic limit rod 453 buffers and limits the auxiliary movable frame 452, so that the settled solid particles on the surface of the adjustable rake frame 441 fall off and return to the initial position.

[0212] S403, the rotation of the hollow drive shaft 324 can drive the scraper support seat 51 to rotate, so that the scraper support seat 51 drives the inclined support arm 521, the side scraping arm 522, and the auxiliary scraping arm 523 to rotate, thereby realizing the synchronous and rapid scraping of the solid particles settled at the bottom of the deep cone thickening tank 21 by the side scraping arm 522 and the auxiliary scraping arm 523.

[0213] S404, when the scraper support seat 51 drives the oblique support arm 521, the side scraping arm 522, and the auxiliary scraping arm 523 to rotate, the limiting gear ring 532 meshes with the linkage gear 531, so that the linkage gear 531 drives the anti-blocking linkage shaft 534 to rotate, and the anti-blocking linkage shaft 534 drives the spiral spoiler belt 533 to rotate, so that the spiral spoiler belt 533 moves the solid particles at the edge of the deep cone thickening tank 21 to the central area, and the high-concentration phosphogypsum slurry after sedimentation and concentration is discharged to the phosphogypsum filling slurry preparation system.

[0214] In summary, the present invention provides a filling process and equipment based on the pretreatment of phosphogypsum pipeline transportation and the recovery of fluorine and phosphorus. In an embodiment of the present invention, an anti-pressure rake mechanism 4 is provided, which consists of an upper rake seat 41, a lower rake seat 42, an adjustable rake seat 44, and a rake seat protection portion 45. The technical means of the coordinated cooperation of the adjustable rake seat 44 and the rake seat protection portion 45 can ensure that the APAM flocculant and the pretreated phosphogypsum slurry are evenly mixed, avoiding the "rake pressure" phenomenon caused by the rapid sedimentation of the phosphogypsum slurry, which in turn causes the incomplete separation of soluble fluorine and phosphorus elements. At the same time, the adjustable rake seat 44 can also change its own scraping angle when the "rake pressure" phenomenon occurs, reduce its own load, avoid damage to the adjustable rake seat 44, extend the service life of the adjustable rake seat 44, ensure that the soluble fluorine and phosphorus elements in the phosphogypsum slurry are separated and thoroughly stirred, which is beneficial to the combination of APAM flocculant and gypsum slurry to prepare a homogeneous filling slurry, and then transport the above-mentioned homogeneous filling slurry to the underground goaf through the filling industrial pump, thereby realizing the comprehensive utilization of phosphogypsum waste and the management of underground goaf. The method overcomes the problem that the soluble fluorine and phosphorus elements in the filling body cannot be effectively separated by the existing method, the soluble fluorine and phosphorus elements leached out in excess of the standard after long-term immersion in groundwater, there is a potential risk of groundwater environmental pollution, and it is difficult to use them directly for filling.

[0215] It should be noted that for the aforementioned embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, because according to the present invention, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0216] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also fall within the scope of protection of the present invention.

Claims

1. Filling equipment based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus, including: A deep cone thickener (2), the deep cone thickener (2) is fixedly installed in the equipment base (11), the deep cone thickener (2) includes a deep cone thickener tank (21), a feeding port (22), an overflow weir (23), and a concentrated material outlet (24), the feeding port (22) and the concentrated material outlet (24) are respectively arranged at the upper and lower ends of the deep cone thickener tank (21), the overflow weir (23) is opened on the outside of the feeding port (22), and the overflow weir (23) and the feeding port (22) are connected, a pretreatment feeding pipe (25) is provided at the top of the feeding port (22), and the pretreatment feeding pipe (25) is fixedly installed in the equipment frame (13); A thickening drive assembly (3), wherein the thickening drive assembly (3) is fixedly mounted on an equipment frame (13); At least one set of anti-pressure rake mechanisms (4), characterized in that the anti-pressure rake mechanisms (4) are arranged in the deep cone thickening tank (21), the anti-pressure rake mechanisms (4) are used to stir the material and prevent the concentrated material from being subjected to pressure rake phenomena, and the anti-pressure rake mechanisms (4) are connected to the thickening drive assembly (3); Wherein, the anti-pressure rake mechanism (4) comprises: An upper harrow seat (41), wherein the upper harrow seat (41) is connected to the thickening drive assembly (3); A lower harrow seat (42) is arranged below the upper harrow seat (41), wherein the lower harrow seat (42) is fixedly connected to the upper harrow seat (41) via an oblique support rod (43); an adjustable harrow seat (44), the adjustable harrow seat (44) being arranged in the upper harrow seat (41), the adjustable harrow seat (44) being used for uniformly mixing materials, and A rake seat protection portion (45), the rake seat protection portion (45) being arranged between the upper rake seat (41) and the lower rake seat (42), the rake seat protection portion (45) being connected to the adjustable rake seat (44) and being used to protect the adjustable rake seat (44); The thickening drive assembly (3) comprises: A drive motor (31), wherein the drive motor (31) is fixedly mounted in the equipment frame (13); a drive transmission part (32) fixedly connected to the output shaft of the drive motor (31), wherein the drive transmission part (32) is used to drive the anti-pressure rake mechanism (4); The adjustable rake seat (44) comprises: at least one set of adjustable rakes (441); A linkage toothed roller (442) fixedly connected to the adjustable harrow frame (441), wherein the linkage toothed roller (442) is rotatably mounted in the upper harrow seat (41); A linkage tooth seat (443) is slidably mounted in the upper harrow seat (41), and both sides of the linkage tooth seat (443) are respectively engaged with the linkage tooth roller (442) for transmission; An anti-settling seat (444) fixedly connected to the linkage gear seat (443); the rake seat protection portion (45) includes: A protection linkage groove (451), wherein the protection linkage groove (451) is provided on a side wall of the adjustable rake frame (441), and a protection linkage block is slidably mounted in the protection linkage groove (451); An auxiliary movable frame (452) fixedly connected to the protective linkage block, wherein the auxiliary movable frame (452) is slidably embedded in a movable guide seat (454), and the movable guide seat (454) is fixedly installed in the upper rake seat (41); A telescopic limit rod (453) is fixedly installed in the upper rake seat (41), and the telescopic rod of the telescopic limit rod (453) is fixedly connected to the side wall of the auxiliary movable frame (452); and further includes a scraper gathering mechanism (5), the scraper gathering mechanism (5) is used to discharge the high-concentration phosphogypsum slurry after concentration at the bottom of the deep cone thickening tank (21) through the concentration discharge port (24), and the scraper gathering mechanism (5) is fixedly connected to the lower end of the hollow drive shaft (324).

2. The filling equipment based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus according to claim 1, characterized in that: The thickening machine body (1) further comprises a thickening machine body (1), wherein the thickening machine body (1) comprises a device base (11), device legs (12), and a device frame (13), wherein a plurality of sets of device legs (12) are fixedly mounted on the device base (11), and the device frame (13) is fixedly mounted on the device base (11).

3. The filling equipment based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus according to claim 2, characterized in that: The driving transmission part (32) comprises: A driving wheel (321), wherein the driving wheel (321) is fixedly connected to an output shaft of the driving motor (31); A driven rotating wheel (322) is arranged on one side of the driving rotating wheel (321), the driven rotating wheel (322) is rotationally connected to the driving rotating wheel (321) via a conveyor belt (323), and the driven rotating wheel (322) is rotatably installed in the equipment frame (13); a hollow drive shaft (324) fixedly connected to the driven rotating wheel (322), wherein the hollow drive shaft (324) is fixedly connected to the upper rake seat (41); An aeration coupling (325) is rotatably sleeved on the outer wall of the hollow drive shaft (324), one side of the aeration coupling (325) is fixedly connected to an air supply pipe (26), and the lower end of the hollow drive shaft (324) is fixedly connected to at least one set of aeration pipes (46).

4. The filling equipment based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus according to claim 3, characterized in that: The scraper gathering mechanism (5) comprises: a scraper support seat (51), the scraper support seat (51) being fixedly connected to the lower end of the hollow drive shaft (324); At least one set of bottom scraper frames (52), wherein the bottom scraper frames (52) are fixedly mounted on the scraper support seat (51), and the bottom scraper frames (52) are used to scrape off the deposited material at the bottom of the deep cone thickening tank (21); An anti-clogging discharge portion (53) is installed in a bottom scraper frame (52) and is used to gather solid particles deposited at the bottom of the deep cone thickening tank (21) toward the center. The bottom scraper frame (52) includes: An oblique support arm (521), wherein the oblique support arm (521) is fixedly mounted in the scraper support seat (51); a side scraping arm (522) fixedly mounted on the end of the oblique support arm (521), the side scraping arm (522) being used to scrape adsorbed matter from the side wall of the deep cone thickening tank (21); An auxiliary scraping arm (523) fixedly connected to the side scraping arm (522), the auxiliary scraping arm (523) also fixedly connected to the end of the scraping support seat (51); the bottom scraping frame (52) further includes: At least one set of side scrapers (524), the side scrapers (524) being fixedly mounted on the side scraping arms (522); At least one set of auxiliary scrapers (525), wherein the auxiliary scrapers (525) are fixedly mounted on the auxiliary scraping arm (523).

5. The filling equipment based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus according to claim 4, characterized in that: The anti-blocking discharge portion (53) comprises: an anti-clogging linkage shaft (534), the anti-clogging linkage shaft (534) being rotatably mounted on the side scraping arm (522); A linkage gear (531), the linkage gear (531) being fixedly mounted on the upper end of the anti-blocking linkage shaft (534); A limiting gear ring (532), wherein the limiting gear ring (532) is fixedly mounted on the inner wall of the deep cone thickening tank (21), and the limiting gear ring (532) is meshed with the linkage gear (531) for transmission; A spiral flow-turbine strip (533) is fixedly mounted on the lower end of the anti-clogging linkage shaft (534), and the spiral flow-turbine strip (533) is used to assist in gathering solid particles at the bottom of the deep cone thickening tank (21).

6. A filling process based on pretreatment of phosphogypsum for pipeline transportation and recovery of fluorine and phosphorus, implemented using the filling equipment based on pretreatment of phosphogypsum for pipeline transportation and recovery of fluorine and phosphorus as claimed in claim 5, characterized in that: The filling process includes: S10, fresh phosphogypsum produced by the phosphoric acid chemical plant is selected, its moisture content and pH value are measured, and the phosphogypsum is conveyed to an industrial mixing barrel via a belt conveyor; S20, adding clean water to storage hopper A, then dissolving the flaky NaOH into a 0.1-0.25 mol / L solution and cooling it to room temperature to complete the preparation of the alkaline detergent, and then using an acid, alkali, and corrosion-resistant clean water pump to pump the low-concentration NaOH solution into the industrial mixing tank; S30, mixing phosphogypsum, low-concentration NaOH solution, and clean water in an industrial mixing barrel to prepare a phosphogypsum slurry with a mass concentration of 10-15%, and transporting the slurry to a deep cone thickener (2) in a filling preparation station by long-distance pipe using turbulent flow technology; S40, adding APAM flocculant and clean water into the storage hopper B, stirring until the APAM flocculant is fully dissolved, and preparing an APAM solution with a mass fraction of 0.5‰, and then using a clean water pump to pump the APAM flocculant to the deep cone thickener (2), the deep cone thickener (2) performs solid-liquid separation and sedimentation concentration on the low-concentration phosphogypsum, the supernatant at the top of the deep cone thickener (2) is discharged to the fluorine-phosphorus recovery system through the overflow weir (23), and the high-concentration phosphogypsum slurry after concentration at the bottom of the deep cone thickener (2) is discharged to the phosphogypsum filling slurry preparation system; S50, fluorine and phosphorus recovery system recovers fluorine and phosphorus; S501, using ultrafiltration or nanofiltration membrane technology, removes fine suspended particles and dissolved fluorine and phosphorus in the supernatant of the deep cone thickener (2) through a semi-permeable membrane; S502, using cation exchange resin and anion exchange resin, the supernatant is passed through the cation exchange resin and anion exchange resin to exchange out cations such as calcium and magnesium in the solution, and F - and PO4 3- Anions are adsorbed on the resin; S503, adding a precipitant to the supernatant to reduce the concentration of fluorine and phosphorus ions in the supernatant; S504, through reverse osmosis treatment to ensure that the supernatant reaches the reuse water standard, using a semi-permeable membrane to separate water molecules from soluble impurities under high pressure; S60, the high-concentration phosphogypsum slurry concentrated at the bottom of the deep cone thickener (2) is transported to the filling preparation station, its moisture content and pH value are tested, clean water and cementitious materials are added, and after being stirred evenly, the required homogeneous cementitious filling slurry is obtained. The homogeneous cementitious filling slurry is transported to the underground goaf through the filling industrial pump.

7. The filling process based on pretreatment of phosphogypsum pipeline transportation and recovery of fluorine and phosphorus according to claim 6, characterized in that: The method for solid-liquid separation and sedimentation concentration of low-concentration phosphogypsum by the deep cone thickener (2) comprises: S401, pumping the APAM flocculant into the feeding port (22) via a clean water pump, then transporting the low-concentration phosphogypsum slurry to the pretreatment feeding pipe (25) via a long-distance pipe, turning on the drive motor (31), and starting the drive motor (31) to drive the active rotor (321) to rotate, and the active rotor (321) drives the driven rotor (322) and the hollow drive shaft (324) to rotate, so that the hollow drive shaft (324) drives the upper rake seat (41) and the lower rake seat (42) to rotate, thereby achieving stirring and mixing of the low-concentration phosphogypsum slurry and the APAM flocculant; S402, when low-concentration phosphogypsum slurry and APAM flocculant are mixed and sedimentation occurs, and excessive solid particles are deposited to produce a "rake pressure" phenomenon, the settled solid particles press down the adjustable rake frame (441), driving the adjustable rake frame (441) to rotate downward, the adjustable rake frame (441) drives the linkage tooth roller (442) to rotate, the linkage tooth roller (442) drives the linkage tooth seat (443) and the anti-settling seat (444) to move upward, so that the anti-settling seat (444) moves the settled solid particles upward, and when the adjustable rake frame (441) swings, it drives the protection linkage groove (451) to swing, and the protection linkage groove (451) drives the auxiliary movable frame (452) to move along the movable guide seat (454), and the telescopic limit rod (453) buffers and limits the auxiliary movable frame (452), so that the settled solid particles on the surface of the adjustable rake frame (441) fall off and return to the initial position; S403, the rotation of the hollow drive shaft (324) can drive the scraper support seat (51) to rotate, so that the scraper support seat (51) drives the oblique support arm (521), the side scraping arm (522), and the auxiliary scraping arm (523) to rotate, thereby achieving the side scraping arm (522) and the auxiliary scraping arm (523) to synchronously and quickly scrape off the solid particles settled at the bottom of the deep cone thickening tank (21); In step S404, when the scraper support seat (51) drives the oblique support arm (521), the side scraper arm (522), and the auxiliary scraper arm (523) to rotate, the limiting gear ring (532) meshes with the linkage gear (531), so that the linkage gear (531) drives the anti-blocking linkage shaft (534) to rotate, and the anti-blocking linkage shaft (534) drives the spiral spoiler belt (533) to rotate, so that the spiral spoiler belt (533) moves the solid particles at the edge of the deep cone thickening tank (21) to gather in the central area, and the high-concentration phosphogypsum slurry after sedimentation and concentration is discharged to the phosphogypsum filling slurry preparation system.

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