An extraction sewage treatment equipment and process for extracting lithium from high magnesium-lithium ratio brine

Abstract

The application provides an extraction sewage treatment equipment and process for extracting lithium from high-magnesium-lithium-ratio brine, relates to the technical field of water pollution treatment, and comprises a reaction tank, a dosing mechanism, a slag scraping mechanism and a slag removal mechanism. The slag scraping mechanism comprises a scraper and two threaded lead screws. The scraper is arranged in the interior of the reaction tank. The two threaded lead screws are threadedly connected with the scraper. First connecting seats are rotationally connected to the left ends of the two threaded lead screws. The scraper continuously moves to the right. The slag removal frame and the filter screen are in an inclined state under the cooperation of the turnover gear and the turnover toothed plate, so that the separated flocculent scum can be further treated. After the floating scum is cleaned, the lime milk and the lower layer of sewage can be better contacted, so that the reaction rate is improved. The scum can be prevented from being carried out by the water flow, so that the secondary entrainment of heavy metals and organic matters is reduced, subsequent reuse or discharge standards are met, and the risk of secondary pollution is avoided.

Description

Technical Field

[0001] This invention relates to the field of water pollution control, and in particular to an extraction wastewater treatment equipment and process for extracting lithium from brine with a high magnesium-to-lithium ratio. Background Technology

[0002] The brine used for lithium extraction is a natural or artificial liquid mineral resource rich in various dissolved salts, especially containing an economically recoverable concentration of lithium. The extraction wastewater generated after extracting lithium resources from brine with a high magnesium-to-lithium ratio is a typical industrial wastewater. It is a complex, high-salt, and difficult-to-degrade organic wastewater that cannot be discharged directly and must undergo strict and effective treatment.

[0003] In related technologies, the extraction wastewater generated from lithium extraction from high magnesium-to-lithium ratio brines is rich in magnesium ions. In environmental water bodies, excessively high concentrations of magnesium can lead to water hardening, affecting aquatic ecosystems and agricultural irrigation, thus requiring treatment. However, existing extraction wastewater treatment equipment is not adept at handling floating flocculent scum when treating extraction wastewater containing magnesium ions. The addition of lime slurry can form amorphous flocculent scum on the wastewater surface. During treatment, the scum may be carried away by the effluent flow, resulting in excessive suspended solids in the effluent and further deteriorating the effluent quality. Moreover, the scum has different properties from the sludge settled at the bottom, and mixing with it may affect the dewatering performance of the sludge.

[0004] Therefore, it is necessary to provide an extraction wastewater treatment equipment and process for extracting lithium from brine with a high magnesium-to-lithium ratio to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides an extraction wastewater treatment device and process for lithium extraction from brine with a high magnesium-to-lithium ratio, which solves the problem that existing extraction wastewater treatment equipment is not convenient for treating floating flocculent scum when treating extraction wastewater containing magnesium ions.

[0006] To solve the above-mentioned technical problems, the extraction wastewater treatment equipment for lithium extraction from high magnesium-to-lithium ratio brine provided by the present invention includes a reaction tank, a dosing mechanism, a slag scraping mechanism, and a slag removal mechanism.

[0007] The slag scraping mechanism includes a scraper and two threaded screws. The scraper is disposed inside the reaction tank. The two threaded screws are threadedly connected to the scraper. The left end of each of the two threaded screws is rotatably connected to a first connecting seat, and the right end of each of the two threaded screws is rotatably connected to a second connecting seat. A drive motor for driving the threaded screws to rotate is disposed on the left side of each of the two first connecting seats.

[0008] The slag removal mechanism includes two mounting frames, a slag removal frame, and a filter screen. The two mounting frames are fixedly connected to the inner wall of the reaction tank on opposite sides. Each of the two mounting frames is vertically rotatably connected to an adjusting screw. Each of the two adjusting screws is threaded with a screw block. The slag removal frame is rotatably connected to the opposite side of the two screw blocks. The surface of the slag removal frame is fixedly provided with two flipping gears. Each of the two mounting frames is fixedly provided with a flipping toothed plate on opposite sides. Each of the top ends of the two adjusting screws is fixedly provided with a rotating gear. The surface of the scraper is fixedly provided with two driving toothed plates.

[0009] Preferably, the filter screen is fixed to the inner side of the slag removal frame, the two screw blocks are slidably connected to the inner walls of the two mounting brackets respectively, and the two flip gears move upward and mesh with the two flip tooth plates respectively, driving the slag removal frame to rotate clockwise.

[0010] Preferably, the dosing mechanism includes two rotating seats fixed to the top of the reaction tank, with a dosing pipe rotatably connected to the inner side of the two rotating seats. Multiple dosing nozzles are connected to the surface of the dosing pipe, and two oscillating gears are fixed to the surface of the dosing pipe. Oscillating toothed plates are fixed to both the front and back of the scraper.

[0011] Preferably, a cleaning mechanism is rotatably connected inside the reaction tank. The cleaning mechanism includes a cleaning pipe rotatably connected inside the reaction tank. Multiple cleaning nozzles are connected to the surface of the cleaning pipe. Two adjusting gears are fixedly provided on the surface of the cleaning pipe. Two adjusting toothed plates are fixedly provided on the right side of the scraper.

[0012] Preferably, a collection mechanism is fixedly provided on the right side of the inner wall of the reaction tank. The collection mechanism includes a collection rack fixedly provided on the right side of the inner wall of the reaction tank, a telescopic frame provided on the top of the collection rack, and two electric telescopic rods fixedly provided on the right side of the reaction tank. The output ends of the two electric telescopic rods are fixedly connected to the telescopic frame.

[0013] Preferably, a mixing mechanism is laterally rotatably connected inside the reaction tank. The mixing mechanism includes a mixing shaft laterally rotatably connected inside the reaction tank. Multiple mixing paddles are fixed on the surface of the mixing shaft. A mixing motor that drives the mixing shaft to rotate is provided on the left side of the reaction tank.

[0014] Preferably, two crossbeams are fixed on the left side of the top of the reaction tank, and an emulsion tank is provided on the top of the two crossbeams. The top of the emulsion tank is connected to a feed pipe.

[0015] Preferably, the left side of the reaction tank is connected to an inlet pipe, the right side of the reaction tank is connected to an outlet pipe, the right side of the front of the reaction tank is connected to a slag discharge pipe, the bottom of the reaction tank is provided with a support base, and the top of the reaction tank is fixed with two protective frames.

[0016] A process for extracting lithium from brines with a high magnesium-to-lithium ratio includes the following steps:

[0017] Step S1: Preparation of triphenyl phosphate

[0018] S11. Add phenol and dichloromethane to a three-necked flask, stir until completely dissolved, then slowly add the acid-binding agent, mix well, and cool in an ice-water bath.

[0019] S12. Install the condenser, thermometer and constant pressure dropping funnel, and slowly add phosphorus oxychloride. During the dropping process, HCl gas needs to be collected.

[0020] S13. After the addition is complete, remove the ice water bath and continue to slowly heat and stir the reaction.

[0021] S14. After the reaction solution has cooled to room temperature, slowly pour it into ice water to adjust the pH.

[0022] S15. Transfer to a separatory funnel, allow to stand and separate the organic phase, extract the aqueous phase twice with an extractant, and combine the organic phases.

[0023] S16. The organic phase is dried with a drying agent, filtered, and then distilled under reduced pressure to remove dichloromethane to obtain the crude product.

[0024] S17. The crude product is further subjected to vacuum distillation, and the fraction is collected to obtain pure triphenyl phosphate.

[0025] Step S2: Lithium is extracted from brine with a high magnesium-to-lithium ratio using three-stage countercurrent extraction.

[0026] S21. Mix the extractant, synergist and diluent in a certain volume ratio to prepare a solution, and add the co-extractant and stir until completely dissolved;

[0027] S22. Construct a three-stage countercurrent extraction device;

[0028] S23. Add the brine and organic phase to the apparatus separately;

[0029] S24. Continuous cyclic operation, collecting organic and aqueous phase samples from each stage outlet at regular intervals to monitor changes in lithium concentration;

[0030] S25. Add the supported organic phase and hydrochloric acid to a separatory funnel at a certain ratio, and perform back-extraction by shaking in a constant temperature water bath shaker, and then let it stand to separate.

[0031] S26. Collect the lower aqueous phase (extraction solution) and the upper regenerated organic phase. The extraction solution is used for lithium content determination. The regenerated organic phase can be recycled for extraction after being washed with deionized water 2 to 3 times.

[0032] Step S3: Treat the extraction wastewater

[0033] S31, Neutralization and Precipitation: The extraction wastewater is discharged into the reaction tank, and lime milk is sprayed into the reaction tank to adjust the pH to neutral or slightly alkaline, generating magnesium hydroxide precipitate to remove magnesium ions from the extraction wastewater.

[0034] S32. Sedimentation separation: Solid-liquid separation is carried out using a sedimentation tank. The sludge from the bottom flow is then dewatered by a filter press or centrifuge to obtain magnesium hydroxide filter cake.

[0035] S33. Evaporation and crystallization: Evaporation and crystallization are carried out using a multi-effect evaporator or a mechanical vapor recompression evaporator to obtain condensate and crystalline mixed salt.

[0036] Compared with related technologies, the extraction wastewater treatment equipment and process for lithium extraction from high magnesium-to-lithium ratio brines provided by this invention have the following beneficial effects:

[0037] The scraper moves to the right, pushing the flocculent scum to the right side of the reaction tank wall, forming a thicker scum layer. As the scraper moves to the right, it drives the drive toothed plate to move to the right, causing the rotating gear to rotate the adjusting screw. This, in turn, moves the filter screen upwards via the scum removal frame, separating the flocculent scum from the extraction wastewater. As the scraper continues to move to the right, the cooperation of the tilting gear and the tilting toothed plate tilts the scum removal frame and filter screen, facilitating further processing of the separated flocculent scum. After cleaning the floating scum, the lime slurry and the lower wastewater can better contact, increasing the reaction rate and preventing the scum from being carried away by the water flow. This reduces the secondary entrainment of heavy metals and organic matter, meeting subsequent reuse or discharge standards and avoiding the risk of secondary pollution. After removing the flocculent scum, the magnesium hydroxide precipitate generated in the sediment has high purity and does not introduce impurities such as organic matter and heavy metals, allowing for resource recovery. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0039] Figure 1 The optimal structural schematic diagram provided for this invention;

[0040] Figure 2 This is a structural schematic diagram of the right view provided by the present invention;

[0041] Figure 3 This is a schematic diagram of the slag scraping mechanism provided by the present invention;

[0042] Figure 4This is a schematic diagram of the slag removal mechanism provided by the present invention;

[0043] Figure 5 for Figure 4 The diagram shows the state in which the scraper drives the drive toothed plate to move to the right, causing the slag removal frame to move the filter screen upward.

[0044] Figure 6 for Figure 4 The diagram shows the state in which the scraper drives the drive toothed plate to move to the right, causing the flipping gear to move upward. Under the action of the flipping toothed plate, the slag removal frame drives the filter screen to rotate clockwise.

[0045] Figure 7 This is a schematic diagram of the structure of the dosing mechanism provided by the present invention;

[0046] Figure 8 A schematic diagram of the cleaning mechanism provided by the present invention;

[0047] Figure 9 for Figure 8 The diagram shows the state in which the scraper drives the adjusting toothed plate to move to the right, causing the adjusting gear to drive the cleaning plate to rotate.

[0048] Figure 10 A schematic diagram of the collection mechanism provided by the present invention;

[0049] Figure 11 This is a schematic diagram of the structure of the hybrid mechanism provided by the present invention.

[0050] Explanation of icon numbers:

[0051] 1. Reaction tank;

[0052] 2. Dosing mechanism; 21. Rotating seat; 22. Dosing pipe; 23. Dosing nozzle; 24. Oscillating gear; 25. Oscillating toothed plate;

[0053] 3. Slag scraping mechanism; 31. Scraper; 32. Lead screw; 33. First connecting seat; 34. Second connecting seat; 35. Drive motor;

[0054] 4. Slag removal mechanism; 41. Mounting frame; 42. Slag removal frame; 43. Filter screen; 44. Adjusting screw; 45. Screw block; 46. Tilting gear; 47. Tilting toothed plate; 48. Rotating gear; 49. Drive toothed plate;

[0055] 5. Cleaning mechanism; 51. Cleaning pipe; 52. Cleaning nozzle; 53. Adjusting gear; 54. Adjusting toothed plate;

[0056] 6. Collection mechanism; 61. Collection rack; 62. Telescopic rack; 63. Electric telescopic pole;

[0057] 7. Mixing mechanism; 71. Mixing shaft; 72. Mixing propeller; 73. Mixing motor;

[0058] 8. Horizontal frame; 9. Emulsion tank; 10. Feed pipe;

[0059] 11. Liquid inlet pipe; 12. Liquid outlet pipe; 13. Slag outlet pipe; 14. Support base; 15. Protective frame. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0061] This invention provides an extraction wastewater treatment equipment and process for extracting lithium from brine with a high magnesium-to-lithium ratio.

[0062] First embodiment:

[0063] Please see Figures 1 to 6 An extraction wastewater treatment device for extracting lithium from brine with a high magnesium-to-lithium ratio includes a reaction tank 1, a dosing mechanism 2, a slag scraping mechanism 3, and a slag removal mechanism 4.

[0064] The slag scraping mechanism 3 includes a scraper 31 and two threaded screws 32. The scraper 31 is disposed inside the reaction tank 1. The two threaded screws 32 are threadedly connected to the scraper 31. The left end of each of the two threaded screws 32 is rotatably connected to a first connecting seat 33, and the right end of each of the two threaded screws 32 is rotatably connected to a second connecting seat 34. A drive motor 35 for driving the threaded screws 32 to rotate is disposed on the left side of each of the two first connecting seats 33.

[0065] Please combine Figure 3 Start the drive motor 35. The drive motor 35 rotates and drives the threaded screw 32 to rotate. The rotation of the threaded screw 32 in turn drives the scraper 31 to move to the right. The scraper 31 moves to the right and pushes the flocculent scum floating on the surface of the extracted wastewater to the right, forming a thicker scum layer on the right side of the inner wall of the reaction tank 1.

[0066] Furthermore, the bottom of the scraper 31 has a certain curvature. By moving the scraper 31 left and right at a certain speed, irregular waves can be formed on the surface of the extracted wastewater, thereby promoting the rapid reaction between the lime milk and the extracted wastewater.

[0067] The slag removal mechanism 4 includes two mounting brackets 41, a slag removal frame 42, and a filter screen 43. The two mounting brackets 41 are fixedly connected to the inner wall of the reaction tank 1 on opposite sides. The interior of each of the two mounting brackets 41 is vertically rotatably connected to an adjusting screw 44. The surfaces of the two adjusting screws 44 are threaded with screw blocks 45. The slag removal frame 42 is rotatably connected to the opposite side of the two screw blocks 45. The surface of the slag removal frame 42 is fixedly provided with two flipping gears 46. The opposite sides of the two mounting brackets 41 are fixedly provided with flipping tooth plates 47. The top ends of the two adjusting screws 44 are fixedly provided with rotating gears 48. The surface of the scraper 31 is fixedly provided with two driving tooth plates 49.

[0068] Please combine Figures 4 to 6 When the scraper 31 moves to the right and pushes the flocculent scum to the right, it will simultaneously drive the two drive tooth plates 49 to move to the right. After the two drive tooth plates 49 contact the two rotating gears 48 respectively, they will drive the adjusting screw 44 to rotate through the rotating gears 48. The rotation of the adjusting screw 44 will drive the two screw blocks 45 to move upward. The upward movement of the screw blocks 45 will drive the scum removal frame 42 and the filter screen 43 to move upward. The filter screen 43 will separate the flocculent scum from the extraction wastewater, so that the flocculent scum will be separated from the extraction wastewater.

[0069] Furthermore, as the scraper 31 continues to move to the right, after the flocculent scum is separated from the extraction wastewater, during the upward movement of the slag removal frame 42, the two flipping gears 46 will contact the two flipping tooth plates 47 respectively, thereby driving the slag removal frame 42 and the filter screen 43 to rotate clockwise, so that the slag removal frame 42 and the filter screen 43 are in an inclined state, which facilitates further processing of the separated flocculent scum.

[0070] The filter screen 43 is fixed to the inner side of the slag removal frame 42. The two screw blocks 45 are slidably connected to the inner walls of the two mounting brackets 41 respectively. The two flip gears 46 move upward and mesh with the two flip tooth plates 47 respectively, and drive the slag removal frame 42 to rotate clockwise.

[0071] Preferably, after lime milk is added to the wastewater for extraction, the acid-base neutralization reaction generates heat, causing tiny bubbles to precipitate in the solution. During the stirring process, air is inevitably drawn in, forming a large number of tiny bubbles. These tiny bubbles attach to the magnesium hydroxide flocs, increasing their buoyancy and causing them to rise rapidly to the surface of the liquid, thus forming flocculent scum.

[0072] In this embodiment, the scraper 31 moves to the right, pushing the flocculent scum to the right side of the inner wall of the reaction tank 1, forming a thicker scum layer. When the scraper 31 moves to the right, it drives the drive toothed plate 49 to move to the right, causing the rotating gear 48 to drive the adjusting screw 44 to rotate. The scum removal frame 42 drives the filter screen 43 to move upward, separating the flocculent scum from the extraction wastewater. As the scraper 31 continues to move to the right, with the cooperation of the flipping gear 46 and the flipping toothed plate 47, the scum removal frame 42 and the filter screen 43 are tilted, which facilitates further processing of the separated flocculent scum. After cleaning the floating scum, the lime milk and the lower wastewater can better contact, thereby increasing the reaction rate and preventing the scum from being carried out by the water flow, thus reducing the secondary entrainment of heavy metals and organic matter, meeting the subsequent reuse or discharge standards, and avoiding the risk of secondary pollution. After removing the flocculent scum, the magnesium hydroxide precipitate generated in the sediment will have a high purity and will not introduce impurities such as organic matter and heavy metals, which can be recycled.

[0073] Second embodiment:

[0074] Please see Figure 1 , Figures 7 to 9 The dosing mechanism 2 includes two rotating seats 21 fixed to the top of the reaction tank 1. The inner sides of the two rotating seats 21 are rotatably connected to a dosing pipe 22. The surface of the dosing pipe 22 is connected to a plurality of dosing nozzles 23. The surface of the dosing pipe 22 is fixedly provided with two oscillating gears 24. The front and back sides of the scraper 31 are both fixedly provided with oscillating toothed plates 25.

[0075] Please combine Figure 1 and Figure 7 When the scraper 31 moves to the right, it will simultaneously drive the two oscillating toothed plates 25 to move to the right. After the oscillating toothed plates 25 move to the right and come into contact with the oscillating gear 24, they will drive the dosing pipe 22 to rotate, thereby adjusting the direction of the lime slurry sprayed by the dosing nozzle 23, improving the mixing efficiency of the lime slurry and the extraction wastewater. In addition, the waves generated during the movement of the scraper 31 can have a diffusion effect on the lime slurry. After the lime slurry reacts with the extraction wastewater, magnesium hydroxide precipitate will be generated, thereby removing magnesium ions from the extraction wastewater and solving the problem that high concentrations of magnesium in the extraction wastewater are toxic to aquatic organisms and cause water hardening.

[0076] The reaction tank 1 is rotatably connected to a cleaning mechanism 5. The cleaning mechanism 5 includes a cleaning pipe 51 rotatably connected to the inside of the reaction tank 1. Multiple cleaning nozzles 52 are connected to the surface of the cleaning pipe 51. Two adjusting gears 53 are fixedly provided on the surface of the cleaning pipe 51. Two adjusting toothed plates 54 are fixedly provided on the right side of the scraper 31.

[0077] Please combine Figure 8 and Figure 9When the flocculent scum is separated from the extraction wastewater by the filter screen 43, and the flocculent scum is removed from the extraction wastewater, the scraper 31 continues to move to the right, which drives the two adjusting tooth plates 54 to move to the right. After the adjusting tooth plates 54 move to the right and come into contact with the adjusting gear 53, the cleaning pipe 51 is rotated. The cleaning nozzles 52 on the surface of the cleaning pipe 51 are directed toward the inclined scum removal frame 42 and the filter screen 43. The water sprayed by the cleaning nozzles 52 cleans the flocculent scum remaining on the surface of the filter screen 43.

[0078] Furthermore, when the cleaning pipe 51 rotates, the scraper 31 moves left and right, and under the action of the adjusting toothed plate 54, it drives the adjusting gear 53 to rotate back and forth. The adjusting gear 53 then drives the cleaning pipe 51 and the cleaning nozzle 52 to swing back and forth. In addition, the left and right movement of the scraper 31 will simultaneously drive the driving toothed plate 49 to move left and right, thereby causing the slag removal frame 42 and the filter screen 43 to swing, further improving the cleaning effect on the flocculent scum on the surface of the filter screen 43.

[0079] In this embodiment, by moving the scraper 31 to the right, the cleaning pipe 51 drives the cleaning nozzle 52 to rotate under the cooperation of the adjusting toothed plate 54 and the adjusting gear 53, thus cleaning the flocculent scum on the surface of the filter screen 43. By moving the scraper 31 left and right, the cleaning pipe 51 and the cleaning nozzle 52 swing back and forth, and the slag removal frame 42 drives the filter screen 43 to swing back and forth, further improving the cleaning effect of flocculent scum on the surface of the filter screen 43. By combining directional rinsing and swing rinsing, the residual scum on the surface of the filter screen 43 is accurately removed, and cleaning dead corners are avoided.

[0080] Third embodiment:

[0081] Please see Figure 1 , Figure 2 , Figure 10 and Figure 11 A collection mechanism 6 is fixedly provided on the right side of the inner wall of the reaction tank 1. The collection mechanism 6 includes a collection rack 61 fixedly provided on the right side of the inner wall of the reaction tank 1. A telescopic rack 62 is provided on the top of the collection rack 61. Two electric telescopic rods 63 are fixedly provided on the right side of the reaction tank 1. The output ends of the two electric telescopic rods 63 are fixedly connected to the telescopic rack 62.

[0082] Please combine Figure 10 When the flocculent scum is separated from the extraction wastewater by the filter screen 43, and the flocculent scum is removed from the extraction wastewater, the electric telescopic rod 63 is activated. The electric telescopic rod 63 extends and drives the telescopic frame 62 to move to the left, so that the telescopic frame 62 is at the bottom of the scum removal frame 42. After the scum removal frame 42 drives the filter screen 43 to tilt, the flocculent scum will fall to the top of the telescopic frame 62 and be collected by the collection frame 61.

[0083] The reaction tank 1 is laterally rotatably connected to a mixing mechanism 7. The mixing mechanism 7 includes a mixing shaft 71 laterally rotatably connected to the inside of the reaction tank 1. Multiple sets of mixing paddles 72 are fixed on the surface of the mixing shaft 71. A mixing motor 73 that drives the mixing shaft 71 to rotate is provided on the left side of the reaction tank 1.

[0084] Please combine Figure 11 When lime slurry is added to the extraction wastewater, the mixing motor 73 is started simultaneously. The rotation of the mixing motor 73 drives the mixing shaft 71 and multiple sets of mixing paddles 72 to rotate, mixing the lime slurry and the extraction wastewater. In the initial stage of the reaction, the mixing paddles 72 stir rapidly, and in the later stage of the reaction, the mixing paddles 72 stir slowly.

[0085] Two horizontal frames 8 are fixedly installed on the left side of the top of the reaction tank 1, and an emulsion tank 9 is installed on the top of the two horizontal frames 8. The top of the emulsion tank 9 is connected to the feed pipe 10.

[0086] Preferably, the emulsion tank 9 is used to store lime slurry, and the emulsion tank 9 is connected to the dosing pipe 22 via a delivery pump and a hose;

[0087] The left side of the reaction tank 1 is connected to an inlet pipe 11, the right side of the reaction tank 1 is connected to an outlet pipe 12, the right side of the front of the reaction tank 1 is connected to a slag discharge pipe 13, the bottom of the reaction tank 1 is provided with a support base 14, and the top of the reaction tank 1 is fixed with two protective frames 15.

[0088] In this embodiment, the telescopic frame 62 is extended to the left by the electric telescopic rod 63 to collect the flocculent scum and ensure that the flocculent scum will not fall back into the extraction wastewater. The rotation of the mixing motor 73 drives the mixing shaft 71 and multiple mixing paddles 72 to rotate, thereby mixing the lime milk and the extraction wastewater.

[0089] Fourth embodiment:

[0090] A process for extracting lithium from brines with a high magnesium-to-lithium ratio includes the following steps:

[0091] Step S1: Preparation of triphenyl phosphate

[0092] S11. Add phenol and dichloromethane to a three-necked flask, stir until completely dissolved, then slowly add the acid-binding agent, mix well, and cool in an ice-water bath.

[0093] Preferably, the acid-binding agent is pyridine, and the temperature of the ice-water bath is 10-15℃;

[0094] S12. Install the condenser, thermometer and constant pressure dropping funnel, and slowly add phosphorus oxychloride. During the dropping process, HCl gas needs to be collected.

[0095] Preferably, the dropping rate is 1-2 ml / min, and the HCl gas is absorbed by a gas absorption device (a beaker containing NaOH solution) connected to the top of the condenser tube;

[0096] S13. After the addition is complete, remove the ice water bath and continue to slowly heat and stir the reaction.

[0097] Preferably, the temperature is raised to 40-50℃ and the reaction is carried out for 2-3 hours;

[0098] S14. After the reaction solution has cooled to room temperature, slowly pour it into ice water to adjust the pH.

[0099] Preferably, the pH is adjusted to 7-8 using a 10% NaOH solution;

[0100] S15. Transfer to a separatory funnel, allow to stand and separate the organic phase, extract the aqueous phase twice with an extractant, and combine the organic phases.

[0101] Preferably, the extractant is dichloromethane;

[0102] S16. The organic phase is dried with a desiccant, filtered, and then distilled under reduced pressure to remove dichloromethane to obtain the crude product.

[0103] Preferably, the desiccant is anhydrous magnesium sulfate, and the vacuum distillation temperature is 30-40℃ and the vacuum degree is ≤0.09 MPa;

[0104] S17. The crude product is further subjected to vacuum distillation, and the fraction is collected to obtain pure triphenyl phosphate.

[0105] Preferably, the vacuum degree is 0.1~0.5 mmHg, and the temperature for collecting the distillate is 180~190℃;

[0106] Step S2: Lithium is extracted from brine with a high magnesium-to-lithium ratio using three-stage countercurrent extraction.

[0107] S21. Mix the extractant, synergist and diluent in a certain volume ratio to prepare a solution, add the co-extractant and stir until completely dissolved;

[0108] Preferably, the extractant is triphenyl phosphate (TPP), the synergist is tributyl citrate (TBC), the diluent is sulfonated kerosene, and the co-extractant is ferric chloride hexahydrate (FeCl3·6H2O). TPP, TBC, and sulfonated kerosene are mixed in a ratio of 40%:20%:40%, wherein the amount of ferric chloride hexahydrate (FeCl3·6H2O) added is such that the Fe content in the organic phase is... 3+ The concentration is 1.0 mol / L, and the solution pH needs to be controlled between 2 and 3;

[0109] S22. Construct a three-stage countercurrent extraction device;

[0110] Preferably, the three-stage countercurrent extraction device is constructed as follows: six separating funnels are divided into three groups of two (one for mixing and one for clarification); a peristaltic pump is connected to the separating funnels to ensure that the organic phase enters from the third stage and passes through the second and first stages in sequence; the aqueous phase enters from the first stage and passes through the second and third stages in sequence, forming a countercurrent flow.

[0111] S23. Add the brine and organic phase to the apparatus separately;

[0112] Preferably, brine is added to the first-stage mixing funnel, and the organic phase is added to the third-stage mixing funnel;

[0113] S24. Continuous cyclic operation, collecting organic and aqueous phase samples from each stage outlet at regular intervals to monitor changes in lithium concentration;

[0114] Preferably, the specific cyclic operation is as follows: start the peristaltic pump and set the flow rate of both the organic phase and the aqueous phase to 1 mL / min (flow rate ratio 1:1); the material in each mixing funnel is shaken at 200 rpm for 15 minutes in a constant temperature water bath shaker; after shaking, the mixture is transferred to the corresponding clarifying funnel and allowed to stand for 10 minutes to allow the two phases to separate completely; the clarified organic phase is transferred to the previous mixing funnel and the aqueous phase is transferred to the next mixing funnel using the peristaltic pump.

[0115] Preferably, the continuous cyclic operation is performed for 3-5 cycles, and organic and aqueous phase samples are collected from each stage outlet every 30 minutes;

[0116] S25. Add the supported organic phase and hydrochloric acid to a separatory funnel at a certain ratio, and perform back-extraction by shaking in a constant temperature water bath shaker, and then let it stand to separate.

[0117] Preferably, the hydrochloric acid concentration is 6 mol / L, and the ratio (O / A) is 1:1;

[0118] S26. Collect the lower aqueous phase (extraction solution) and the upper regenerated organic phase. The extraction solution is used for lithium content determination. The regenerated organic phase can be recycled for extraction after being washed with deionized water 2 to 3 times.

[0119] Preferably, the rotation speed of the constant temperature water bath shaker is 200-300 rpm, the shaking time is 15-20 minutes, and the resting time is 10-15 minutes;

[0120] Step S3: Treat the extraction wastewater

[0121] S31, Neutralization and Precipitation: The extraction wastewater is discharged into reaction tank 1, and lime milk is sprayed into reaction tank 1 to adjust the pH to neutral or slightly alkaline, generating magnesium hydroxide precipitate to remove magnesium ions from the extraction wastewater.

[0122] S32. Sedimentation separation: Solid-liquid separation is carried out using a sedimentation tank. The sludge from the bottom flow is then dewatered by a filter press or centrifuge to obtain magnesium hydroxide filter cake.

[0123] S33. Evaporation and crystallization: Evaporation and crystallization are carried out using a multi-effect evaporator or a mechanical vapor recompression evaporator to obtain condensate and crystalline mixed salt.

[0124] In this embodiment, a lithium extraction method using a synergistic system of triphenyl phosphate and tributyl citrate in sulfonated kerosene and ferric chloride was adopted, which achieved a lithium-magnesium separation coefficient ≥500 and a lithium extraction rate ≥95%, which is much higher than the extraction rate of a single stage.

[0125] In the organic phase, triphenyl phosphate (TPP) contains a strong electron-donating group (P=O), which coordinates with Li. + Formation of hydrophobic complexes (such as Li) + The formation of a coordination bond with the P=O group of TPP is the core driving force for lithium extraction. Tributyl citrate (TBC) molecules contain an ester group (-COO-) and a potentially coordinating oxygen atom. Through hydrogen bonding or dipole-dipole interactions with TPP, it synergizes with TPP, enhancing intermolecular association of the extractant and forming a mixed ligand (TPP-TBC associative complex), thereby improving the extraction efficiency for Li. + Its complexing ability can regulate the viscosity and polarity of the organic phase, improve the flowability of the two phases, and promote mass transfer. Sulfonated kerosene, as an inert diluent, dissolves TPP and TBC, reduces the viscosity of the organic phase, and at the same time avoids the loss of the extractant due to dissolution in the aqueous phase.

[0126] In the aqueous phase, Fe is affected by the salting-out effect. 3+ and Cl - Increase the ionic strength of the aqueous phase and compress Li + The solvation layer makes it easier for organic phase extractants to capture it (the higher the ionic strength, the higher the lithium partition ratio).

[0127] Three-stage countercurrent extraction involves the organic and aqueous phases flowing countercurrently in a three-stage countercurrent apparatus (i.e., the organic phase flows from the third stage to the first stage, and the aqueous phase flows from the first stage to the third stage). In each stage, Li... + Diffusion occurs from the aqueous phase to the organic phase, where lithium complexes with TPP / TBC. Once extraction equilibrium is reached at each stage, the aqueous phase moves to the next stage, while the organic phase flows to the next stage. Through multi-stage contact, lithium is gradually enriched. Compared to single-stage extraction, multi-stage countercurrent extraction is driven by a concentration gradient (the lithium concentration in the aqueous phase decreases from the first stage to the third stage, while the lithium concentration in the organic phase increases), breaking through the limitations of single-stage equilibrium. The extraction rate can be increased to over 95%, reducing the amount of extractant used and increasing the lithium enrichment factor. Countercurrent operation maximizes the mass transfer driving force (the lithium concentration difference between the organic and aqueous phases) at each stage, while also facilitating continuous industrial operation.

[0128] Synergistic effect between extractants: Mixed ligands enhance complexation ability; the P=O group of TPP and the ester oxygen atom of TBC form an association (TPP-TBC) through hydrogen bonding or dipole interaction. This association has a strong effect on Li + The complexing ability of TPP is significantly stronger than that of a single extractant, and the extraction of Li by a single TPP extractant is significantly stronger. + At this time, mononuclear complexes (such as Li) are mainly formed. + • TPP), TPP-TBC associative compounds can form more stable polynuclear complexes (such as Li) through "dual coordination sites". + • TPP and TBC) reduce the solubility of the complex in the aqueous phase, increasing the partition ratio. The addition of TBC reduces the viscosity of the organic phase, improving the rate of phase separation and avoiding the mass transfer resistance caused by the high viscosity of TPP alone. The synergistic effect of FeCl3 and the extractant: FeCl3 ionizes to release high concentrations of Cl... - Reduce Li through salting-out effect + The hydration energy makes it easier for the organic phase to extract it. When the ionic strength of the aqueous phase increases from 0.1 mol / L (NaCl) to 1.5 mol / L (FeCl3), the lithium partition ratio can be increased by 3 to 5 times.

[0129] Please refer to the reference again. Figures 1 to 11 The working principle of the extraction wastewater treatment equipment for lithium extraction from high magnesium-to-lithium ratio brines provided by this invention is as follows:

[0130] Step S1: Discharge the extraction wastewater into the reaction tank 1, add lime slurry into the reaction tank 1 through the dosing pipe 22, and then start the mixing motor 73. The rotation of the mixing motor 73 drives the mixing shaft 71 and multiple sets of mixing paddles 72 to rotate, thereby mixing the lime slurry and the extraction wastewater.

[0131] Start the drive motor 35. The drive motor 35 rotates and drives the threaded screw 32 to rotate. The rotation of the threaded screw 32 in turn drives the scraper 31 and the two swing tooth plates 25 to move to the right. After the swing tooth plates 25 move to the right and come into contact with the swing gear 24, they drive the dosing pipe 22 to rotate, thereby adjusting the direction of the lime milk sprayed from the dosing nozzle 23.

[0132] Step S2: After flocculent scum is generated on the surface of the extracted wastewater, the scraper 31 moves to the right to push the flocculent scum floating on the surface of the extracted wastewater to the right, forming a thicker scum layer on the right side of the inner wall of the reaction tank 1.

[0133] When the scraper 31 moves to the right and pushes the flocculent scum to the right, it will simultaneously drive the two drive tooth plates 49 to move to the right. After the two drive tooth plates 49 contact the two rotating gears 48 respectively, they will drive the adjusting screw 44 to rotate through the rotating gears 48. The rotation of the adjusting screw 44 will drive the two screw blocks 45 to move upward. The upward movement of the screw blocks 45 will drive the scum removal frame 42 and the filter screen 43 to move upward. The filter screen 43 will separate the flocculent scum from the extraction wastewater, so that the flocculent scum will be separated from the extraction wastewater.

[0134] In step S3, as the scraper 31 continues to move to the right, the flocculent scum is separated from the extraction wastewater. During the upward movement of the slag removal frame 42, the two flipping gears 46 will contact the two flipping tooth plates 47 respectively, thereby driving the slag removal frame 42 and the filter screen 43 to rotate clockwise, so that the slag removal frame 42 and the filter screen 43 are in an inclined state.

[0135] Start the electric telescopic rod 63. The electric telescopic rod 63 extends and drives the telescopic frame 62 to move to the left, so that the telescopic frame 62 is at the bottom of the slag removal frame 42. After the slag removal frame 42 drives the filter screen 43 to tilt, the flocculent scum will fall to the top of the telescopic frame 62 and be collected by the collection frame 61.

[0136] In step S4, combined with step S3, the scraper 31 continues to move to the right, which will simultaneously drive the two adjusting tooth plates 54 to move to the right. After the adjusting tooth plates 54 move to the right and come into contact with the adjusting gear 53, they will drive the cleaning tube 51 to rotate, so that the cleaning nozzles 52 on the surface of the cleaning tube 51 face the inclined slag removal frame 42 and the filter screen 43. The water sprayed by the cleaning nozzles 52 cleans the flocculent scum remaining on the surface of the filter screen 43.

[0137] When the cleaning pipe 51 rotates, the scraper 31 moves left and right, and under the action of the adjusting toothed plate 54, it drives the adjusting gear 53 to rotate back and forth. The adjusting gear 53 then drives the cleaning pipe 51 and the cleaning nozzle 52 to swing back and forth. In addition, the left and right movement of the scraper 31 will simultaneously drive the driving toothed plate 49 to move left and right, causing the slag removal frame 42 and the filter screen 43 to swing, switching from directional rinsing to swing rinsing.

[0138] Step S5: After rinsing the flocculent scum off the surface of the filter screen 43, the device is reset by moving the scraper 31 to the left. Then, the flocculent scum in the collection rack 61 is discharged through the scum discharge pipe 13, and the extraction wastewater after the reaction is discharged through the liquid discharge pipe 12 for further processing.

[0139] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An extraction wastewater treatment device for lithium extraction from high magnesium-to-lithium ratio brines, characterized in that, This includes a reaction tank, a dosing mechanism, a slag scraping mechanism, and a slag removal mechanism; The slag scraping mechanism includes a scraper and two threaded screws. The scraper is disposed inside the reaction tank. The two threaded screws are threadedly connected to the scraper. The left end of each of the two threaded screws is rotatably connected to a first connecting seat, and the right end of each of the two threaded screws is rotatably connected to a second connecting seat. A drive motor for driving the threaded screws to rotate is disposed on the left side of each of the two first connecting seats. The slag removal mechanism includes two mounting frames, a slag removal frame, and a filter screen. The two mounting frames are fixedly connected to the inner wall of the reaction tank on opposite sides. Each of the two mounting frames is vertically rotatably connected to an adjusting screw. Each of the two adjusting screws is threaded with a screw block. The slag removal frame is rotatably connected to the opposite side of the two screw blocks. The surface of the slag removal frame is fixedly provided with two flipping gears. Each of the two mounting frames is fixedly provided with a flipping tooth plate on the opposite side. Each of the top ends of the two adjusting screws is fixedly provided with a rotating gear. The surface of the scraper is fixedly provided with two driving tooth plates. The filter screen is fixed to the inside of the slag removal frame. The two screw blocks are slidably connected to the inner walls of the two mounting brackets respectively. The two flip gears move upward and mesh with the two flip tooth plates respectively, driving the slag removal frame to rotate clockwise.

2. The extraction wastewater treatment equipment for lithium extraction from high magnesium-to-lithium ratio brines according to claim 1, characterized in that, The dosing mechanism includes two rotating seats fixed to the top of the reaction tank. The inner sides of the two rotating seats are rotatably connected to a dosing pipe. Multiple dosing nozzles are connected to the surface of the dosing pipe. Two oscillating gears are fixed to the surface of the dosing pipe. Oscillating toothed plates are fixed to both the front and back of the scraper.

3. The extraction wastewater treatment equipment for lithium extraction from high magnesium-to-lithium ratio brine according to claim 1, characterized in that, The reaction tank is rotatably connected to a cleaning mechanism, which includes a cleaning pipe rotatably connected to the inside of the reaction tank. Multiple cleaning nozzles are connected to the surface of the cleaning pipe, and two adjusting gears are fixedly mounted on the surface of the cleaning pipe. Two adjusting toothed plates are fixedly mounted on the right side of the scraper.

4. The extraction wastewater treatment equipment for lithium extraction from high magnesium-to-lithium ratio brines according to claim 1, characterized in that, A collection mechanism is fixedly installed on the right side of the inner wall of the reaction tank. The collection mechanism includes a collection rack fixedly installed on the right side of the inner wall of the reaction tank. A telescopic frame is provided on the top of the collection rack. Two electric telescopic rods are fixedly installed on the right side of the reaction tank. The output ends of the two electric telescopic rods are fixedly connected to the telescopic frame.

5. The extraction wastewater treatment equipment for lithium extraction from high magnesium-to-lithium ratio brines according to claim 1, characterized in that, The reaction tank is laterally rotatably connected to a mixing mechanism, which includes a mixing shaft laterally rotatably connected to the inside of the reaction tank. Multiple mixing paddles are fixed on the surface of the mixing shaft, and a mixing motor that drives the mixing shaft to rotate is provided on the left side of the reaction tank.

6. The extraction wastewater treatment equipment for lithium extraction from high magnesium-to-lithium ratio brines according to claim 1, characterized in that, Two horizontal frames are fixed on the left side of the top of the reaction tank, and an emulsion tank is installed on the top of the two horizontal frames. The top of the emulsion tank is connected to a feed pipe.

7. The extraction wastewater treatment equipment for lithium extraction from high magnesium-to-lithium ratio brines according to claim 1, characterized in that, The reaction tank has an inlet pipe on the left side, an outlet pipe on the right side, a slag discharge pipe on the right side of the front of the reaction tank, a support base at the bottom of the reaction tank, and two protective frames fixed on the top of the reaction tank.

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