Organic phase extraction lithium equipment and method for selectively extracting lithium from waste aluminum electrolysis slag

Abstract

The application provides organic phase extraction lithium extraction equipment and a method for selectively extracting lithium from waste aluminum electrolysis slag, relates to the technical field of solid waste resourceization lithium extraction, and comprises an open extraction tank, a float triggering mechanism, a driving mechanism and a feeding opening and closing mechanism. The float triggering mechanism comprises a sliding rail fixed to the back of the inner wall of the open extraction tank, the sliding rail is slidably connected with a sliding seat on the lateral surface, the front surface of the sliding seat is fixedly provided with a sliding support, the front side of the sliding support is fixedly provided with a float, and the front surface of the sliding rail is fixedly provided with two adjusting bolts. The scheme finally realizes the locking of two-stage liquid level height through the cooperation of the first half gear and the transmission gear, can proportionally fix the filling volume of the alkaline leaching liquid and the organic phase, stably achieves the required phase ratio of the extraction process, the feeding ratio of each batch of materials is consistent, the extraction condition fluctuation caused by the artificial feeding deviation is completely avoided, and the lithium extraction reaction condition is uniform.

Description

Technical Field

[0001] This invention relates to the field of lithium extraction from solid waste, and particularly to organic phase extraction lithium extraction equipment and a method for selectively extracting lithium from waste aluminum electrolytic slag. Background Technology

[0002] Waste aluminum electrolytic slag is a solid waste generated during the aluminum electrolysis production process. It mainly includes aluminum ash, overhaul slag, and carbon slag. Its composition is complex, containing large amounts of fluorides, alumina, and enriched lithium, with lithium mainly existing in the form of insoluble sodium lithium cryolite. This slag is classified as hazardous waste with significant toxicity. Under natural storage conditions, soluble fluorides can easily leach out with rainwater, polluting soil and groundwater and causing damage to human bones. The aluminum nitride in the aluminum ash releases toxic and flammable gases when it comes into contact with water, posing an explosion risk. The highly alkaline leachate can also damage the ecological environment. Therefore, the harmless disposal and resource recycling of waste aluminum electrolytic slag is extremely urgent.

[0003] In related technologies, the volume ratio of organic phase to aqueous phase is a key process parameter determining the lithium extraction rate and selectivity in the selective lithium extraction process using waste aluminum electrolytic slag. However, some existing organic phase extraction lithium extraction equipment is not convenient for precisely controlling the volume of aqueous and organic phases added. Most rely on manual metering or simple valve gravity flow to add the organic phase to the extraction tank; that is, alkaline leaching solution is injected first, and then the organic phase is added proportionally based on the estimated volume. However, this method suffers from low control precision and poor batch-to-batch consistency, easily affecting product quality stability. Furthermore, traditional automatic feeding devices often rely on solenoid valves, flow meters, and PLC control systems, resulting in high costs.

[0004] Therefore, it is necessary to provide organic phase extraction lithium extraction equipment and methods for selectively extracting lithium from waste aluminum electrolytic slag to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides an organic phase extraction lithium extraction device and a method for selectively extracting lithium from waste aluminum electrolytic slag, which solves the problem that some existing organic phase extraction lithium extraction devices are not convenient to fix the injection volume of aqueous phase and organic phase in proportion.

[0006] To solve the above-mentioned technical problems, the organic phase extraction lithium extraction equipment provided by the present invention includes an open extraction tank, a float triggering mechanism, a drive mechanism, and a feeding opening and closing mechanism.

[0007] The float triggering mechanism includes a slide rail fixed to the back of the inner wall of the open extraction tank. A sliding seat is slidably connected to the circumferential side of the slide rail. A sliding bracket is fixed to the front of the sliding seat. A float is fixed to the front of the sliding bracket. Two adjusting bolts are fixed to the front of the slide rail. Limiting brackets are fixed to the surfaces of the two adjusting bolts. A triggering tooth plate is fixed to the left side of the float.

[0008] The driving mechanism includes a key rod rotatably connected to the back of the inner wall of the open extraction tank. A first half gear is connected to the key groove on the peripheral side of the key rod. A trigger gear is fixed at the front end of the key rod. The trigger gear meshes with a trigger tooth plate. A first rotating rod is rotatably connected to the back of the inner wall of the open extraction tank and located at the top of the key rod. A transmission gear is fixed on the peripheral side of the first rotating rod. A swing bracket is fixed at the front end of the first rotating rod.

[0009] The feeding opening and closing mechanism includes a feeding main pipe fixed inside the open extraction tank. A sealing ring is fixed on the inner wall of the feeding main pipe. A sealing plug is slidably connected to the inner wall of the feeding main pipe and inside the sealing ring. A sliding rod is fixed on the right side of the sealing plug. The circumferential side of the sliding rod is slidably connected to the inside of the feeding main pipe. A return spring is sleeved on the circumferential side of the sliding rod and inside the feeding main pipe. A drive bracket is fixed at the right end of the sliding rod. A swing bracket is sleeved on the circumferential side of the drive bracket. A feeding branch pipe is connected to the bottom of the feeding main pipe and the bottom of the sealing plug.

[0010] Preferably, during the counterclockwise rotation of the first half gear, it will mesh with the transmission gear and drive the transmission gear to rotate clockwise. The left side of the sealing plug is frustoconical and the right side is cylindrical. The sealing plug seals the sealing ring through the frustoconical design on the left side and seals the feeding branch pipe through the cylindrical design on the right side.

[0011] Preferably, the swing bracket has an inclined groove inside that works in conjunction with the drive bracket. When the swing bracket rotates clockwise, the inclined groove will pull the sealing plug to the right through the drive bracket and the sliding rod, thus canceling the seal on the sealing ring and the feeding branch pipe.

[0012] Preferably, a pH detection interlocking mechanism is rotatably connected to the back side of the inner wall of the open extraction tank. The pH detection interlocking mechanism includes a second rotating rod rotatably connected to the back side of the inner wall of the open extraction tank. The second rotating rod is located at the bottom of the key rod. A second half gear is fixed on the circumferential side of the second rotating rod. The second half gear meshes with a trigger gear. A rotating bracket is fixed on the front end of the second rotating rod. A pH detector is vertically arranged inside the rotating bracket.

[0013] Preferably, a multi-condition pointer display mechanism is fixedly provided on the back of the open extraction tank. The multi-condition pointer display mechanism includes a mounting plate fixedly provided on the back of the open extraction tank, a display plate fixedly provided on the back of the mounting plate, the rear end of the key rod passing through the front of the mounting plate and the display plate in sequence and extending to the back of the display plate, and a display pointer fixedly provided on the rear end of the key rod.

[0014] Preferably, a plurality of fixed supports are fixedly provided on the back of the open extraction tank, and a liquid inlet main is provided on the inner side of the plurality of fixed supports. The liquid inlet main is connected to the feeding branch pipe, and a plurality of liquid inlet branch pipes are connected to the surface of the liquid inlet main.

[0015] Preferably, a mixing mechanism is fixedly provided on the top of the open extraction tank. The mixing mechanism includes a mounting bracket fixedly provided on the top of the open extraction tank. A mixing shaft is vertically arranged inside the mounting bracket. Multiple mixing paddles are arranged on the circumferential side of the mixing shaft. A mixing motor for driving the mixing shaft to rotate is provided on the top of the mounting bracket.

[0016] Preferably, the left side of the open extraction tank is connected to two feed pipes, the bottom of the front of the open extraction tank is connected to a discharge pipe, and the inner side of the open extraction tank is longitudinally provided with two droppers, the bottom of each of the two droppers being connected to multiple drip heads.

[0017] A method for selectively extracting lithium from waste aluminum electrolytic slag includes the following steps:

[0018] Step S1: Crush, grind, and dry the waste aluminum electrolytic slag to obtain fine-grained raw materials;

[0019] Step S2: After mixing the fine-particle raw material with aluminum sulfate, the mixture is calcined to convert the insoluble sodium lithium cryolite into soluble lithium sulfate. At the same time, fluorine combines with aluminum to form aluminum fluoride, thus achieving the initial solidification of fluorine.

[0020] Step S3: Leach the roasted product with water and filter to separate it, to obtain a leachate containing lithium and sodium and a leachate containing aluminum fluoride and aluminum oxide.

[0021] Step S4: Adjust the pH of the lithium and sodium leachate to strong alkalinity, and use an organic phase containing HBL121 extractant for extraction to selectively extract lithium;

[0022] Step S5: The supported organic phase is back-extracted in the aqueous phase using carbon dioxide as the stripping agent to obtain a back-extracting solution rich in lithium bicarbonate.

[0023] Step S6: Heat the back-extraction solution to decompose it, so that lithium bicarbonate is converted into lithium carbonate precipitate. After filtration, washing and drying, battery-grade lithium carbonate product is obtained.

[0024] Step S7: Evaporate and concentrate the raffinate after extraction, cool and crystallize to obtain sodium sulfate by-product, and return the mother liquor to the water leaching process for recycling;

[0025] Step S8: Mix the leaching residue containing aluminum fluoride and aluminum oxide with concentrated sulfuric acid to carry out an acid hydrolysis reaction, so that the aluminum oxide is converted into aluminum sulfate. After water leaching and filtration, an aluminum sulfate solution and aluminum fluoride solid can be recycled back to the roasting process.

[0026] Compared with related technologies, the organic phase extraction lithium extraction equipment provided by this invention has the following beneficial effects:

[0027] First, alkaline leachate is injected into the open extraction tank. After the liquid level rises to the preset first fixed level, the organic phase feeding channel is automatically opened. When the liquid level rises to the second limit level as the organic phase is injected, the feeding of the organic phase is automatically stopped. The two liquid level heights are locked by the cooperation of the first half gear and the transmission gear. The volume of alkaline leachate and organic phase can be fixed proportionally to achieve the required ratio for the extraction process. The feeding ratio of each batch of materials is consistent, which completely avoids fluctuations in the extraction conditions caused by human feeding deviation and ensures uniform lithium extraction reaction conditions.

[0028] The equipment strictly follows the operating sequence of adding alkaline leachate first, followed by organic phase. The feeding channel can only be unlocked after the aqueous phase level reaches the standard. If there is not enough liquid in the tank, the organic phase feeding channel will always be closed. This effectively prevents erroneous operations such as adding organic phase before aqueous phase or organic phase coming into direct contact with high concentration of alkali in advance. It also avoids premature hydrolysis and failure of the extractant due to excessive local alkalinity, automatically realizing the feeding sequence of "water first, oil later" and eliminating erroneous operations. Attached Figure Description

[0029] 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.

[0030] Figure 1 The optimal structural schematic diagram provided for this invention;

[0031] Figure 2 for Figure 1 A schematic diagram of the structure of the open extraction tank (rear view shown);

[0032] Figure 3 A schematic diagram of the structure of the float triggering mechanism, driving mechanism, feeding opening and closing mechanism and pH detection interlocking mechanism provided by the present invention;

[0033] Figure 4 This is a schematic diagram of the structure of the float triggering mechanism provided by the present invention;

[0034] Figure 5 for Figure 4 The diagram shows the structure of the sliding bracket.

[0035] Figure 6 A schematic diagram of the drive mechanism and feeding opening and closing mechanism provided by the present invention;

[0036] Figure 7 for Figure 6 The diagram shows a structural schematic of the cross-sectional view of the feeding main pipe;

[0037] Figure 8 The present invention provides a schematic diagram showing the state in which the float drives the trigger tooth plate to move upward, and the drive bracket drives the sliding rod and the sealing plug to move to the right under the cooperation of the drive mechanism.

[0038] Figure 9 This is a schematic diagram of the pH detection interlocking mechanism provided by the present invention;

[0039] Figure 10 A schematic diagram showing the state in which the rotation of the trigger gear drives the second half gear, the second rotating rod, and the rotating bracket to rotate counterclockwise, as provided by the present invention.

[0040] Figure 11 This is a schematic diagram of the multi-condition pointer display mechanism provided by the present invention;

[0041] Figure 12 A schematic diagram of the structure of the mixing mechanism provided by the present invention;

[0042] Figure 13 This is a schematic diagram of the method flow provided by the present invention.

[0043] Explanation of icon numbers:

[0044] 1. Open extraction tank;

[0045] 2. Float triggering mechanism; 21. Slide rail; 22. Sliding seat; 23. Sliding bracket; 24. Float; 25. Adjusting bolt; 26. Limit bracket; 27. Trigger tooth plate;

[0046] 3. Drive mechanism; 31. Key rod; 32. First half gear; 33. Trigger gear; 34. First rotating rod; 35. Transmission gear; 36. Swing bracket;

[0047] 4. Feeding opening and closing mechanism; 41. Feeding main pipe; 42. Sealing ring; 43. Sealing plug; 44. Sliding rod; 45. Return spring; 46. Drive bracket; 47. Feeding branch pipe;

[0048] 5. pH detection interlock mechanism; 51. Second rotating rod; 52. Second half gear; 53. Rotating bracket; 54. pH detector;

[0049] 6. Multi-condition pointer display mechanism; 61. Installation panel; 62. Display panel; 63. Display pointer;

[0050] 7. Fixed bracket; 8. Main inlet pipe; 9. Branch inlet pipe;

[0051] 10. Mixing mechanism; 101. Mounting bracket; 102. Mixing shaft; 103. Mixing paddle; 104. Mixing motor;

[0052] 11. Feed pipe; 12. Discharge pipe; 13. Drip pipe; 14. Drip head. Detailed Implementation

[0053] 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.

[0054] This invention provides an organic phase extraction lithium extraction device.

[0055] First embodiment:

[0056] Please see Figures 1 to 8 The organic phase extraction lithium extraction equipment includes an open extraction tank 1, a float triggering mechanism 2, a drive mechanism 3, and a feeding opening and closing mechanism 4;

[0057] The float triggering mechanism 2 includes a slide rail 21 fixed to the back of the inner wall of the open extraction tank 1. A sliding seat 22 is slidably connected to the periphery of the slide rail 21. A sliding bracket 23 is fixed to the front of the sliding seat 22. A float 24 is fixed to the front of the sliding bracket 23. Two adjusting bolts 25 are fixed to the front of the slide rail 21. Limiting brackets 26 are fixed to the surfaces of the two adjusting bolts 25. A trigger tooth plate 27 is fixed to the left side of the float 24.

[0058] The drive mechanism 3 includes a key rod 31 rotatably connected to the back of the inner wall of the open extraction tank 1. A first half gear 32 is connected to the key groove on the peripheral side of the key rod 31. A trigger gear 33 is fixed at the front end of the key rod 31. The trigger gear 33 meshes with the trigger tooth plate 27. A first rotating rod 34 is rotatably connected to the back of the inner wall of the open extraction tank 1 and located at the top of the key rod 31. A transmission gear 35 is fixed on the peripheral side of the first rotating rod 34. A swing bracket 36 is fixed at the front end of the first rotating rod 34.

[0059] The feeding opening and closing mechanism 4 includes a feeding main pipe 41 fixed inside the open extraction tank 1. A sealing ring 42 is fixed on the inner wall of the feeding main pipe 41. A sealing plug 43 is slidably connected to the inner wall of the feeding main pipe 41 and inside the sealing ring 42. A sliding rod 44 is fixed on the right side of the sealing plug 43. The circumferential side of the sliding rod 44 is slidably connected to the inside of the feeding main pipe 41. A return spring 45 is sleeved on the circumferential side of the sliding rod 44 and inside the feeding main pipe 41. A drive bracket 46 is fixed at the right end of the sliding rod 44. A swing bracket 36 is sleeved on the circumferential side of the drive bracket 46. A feeding branch pipe 47 is connected to the bottom of the feeding main pipe 41 and the bottom of the sealing plug 43.

[0060] During the counterclockwise rotation of the first half gear 32, it will mesh with the transmission gear 35 and drive the transmission gear 35 to rotate clockwise. The left side of the sealing plug 43 is frustoconical and the right side is cylindrical. The sealing plug 43 seals the sealing ring 42 through the frustoconical design on the left side and seals the feeding branch pipe 47 through the cylindrical design on the right side.

[0061] The swing bracket 36 has an inclined groove inside that works with the drive bracket 46. When the swing bracket 36 rotates clockwise, the inclined groove will pull the sealing plug 43 to the right through the drive bracket 46 and the sliding rod 44, thus canceling the seal on the sealing ring 42 and the feeding branch pipe 47.

[0062] Preferably, the two limiting brackets 26 serve as the upper stroke dead point and lower stroke dead point of the float 24, respectively. When the float 24 rises with the liquid level to the preset upper limit, the upper edge of the sliding seat 22 and the sliding bracket 23 contacts the upper limiting bracket 26, preventing the float 24 from rising further, thereby limiting the highest trigger position of the trigger tooth plate 27.

[0063] When the float 24 descends with the liquid level to the preset lower limit, the lower edge of the sliding seat 22 and the sliding bracket 23 contacts the lower limit bracket 26, preventing the float 24 from descending further, thereby limiting the lowest trigger position of the trigger tooth plate 27.

[0064] Preferably, by rotating the adjusting bolt 25, the installation height of the limiting bracket 26 can be adjusted, and the spatial positions of the upper and lower limit points can be changed independently, thereby flexibly setting the effective sliding stroke range of the float 24;

[0065] Preferably, when using organic phase for extraction, alkaline leachate is first injected into open extraction tank 1. When the liquid level rises to the preset first liquid level height (at this time, the feeding main pipe 41 and the feeding branch pipe 47 are connected, that is, the organic phase feeding channel is open and the organic phase has begun to be injected into the tank), the injection of alkaline leachate is stopped.

[0066] As the organic phase is automatically injected into the tank, when the liquid level rises to the second level, the first half gear 32 will disengage from the transmission gear 35. Under the expansion force of the return spring 45, the sealing plug 43 will slide to the left to seal the sealing ring 42 and the feeding branch pipe 47, thus stopping the injection of the organic phase.

[0067] Preferably, the left side of the sealing plug 43 is frustoconical and the right side is cylindrical. When the sealing plug 43 moves to the right, the gap between the frustoconical and the sealing ring 42 gradually increases from zero, and the flow cross-sectional area of ​​the organic phase increases linearly, thereby achieving a smooth transition effect of initial micro-droplet addition, gradual increase in flow rate, and full-flow, and achieving gradual feeding.

[0068] In the initial stage of extraction using an organic phase containing HBL121 extractant, a stable organic phase distribution has not yet formed in the aqueous phase. If a large amount of organic phase rushes in at this time and directly impacts the high-speed mixing paddle 103, it is very easy to generate tiny droplets and form a stable emulsion layer. The initial micro-droplet addition allows the organic phase to enter the system by penetration and be gradually carried and dispersed by the water flow, which can reduce the tendency of emulsification.

[0069] When the organic phase comes into contact with the alkaline aqueous phase, there is heat of mixing and heat of reaction. Gradual feeding allows the heat to be released slowly with the addition of the organic phase, avoiding an instantaneous temperature rise exceeding the preferred range of 20~30℃ and protecting the thermal stability of the extractant.

[0070] Please combine Figure 8 : An alkaline leachate after pH adjustment is injected into the open extraction tank 1. As the liquid level gradually rises, the buoyancy causes the float 24 to slide upward along the slide rail 21. The float 24 will drive the trigger tooth plate 27 to move upward synchronously. The upward movement of the trigger tooth plate 27 will drive the trigger gear 33 to rotate counterclockwise, which in turn drives the key rod 31 and the first half gear 32 to rotate counterclockwise synchronously. When the first half gear 32 rotates counterclockwise to the meshing position, it will mesh with the upper transmission gear 35, which will drive the transmission gear 35 to rotate clockwise, causing the first rotating rod 34 to drive the swing bracket 36 to swing clockwise.

[0071] The swing bracket 36 has an inclined groove adapted to the drive bracket 46. When it swings clockwise, it will push the drive bracket 46 and the sliding rod 44 to the right with the help of the inclined groove, thereby pulling the sealing plug 43 to the right and compressing the reset spring 45. By moving the sealing plug 43 to the right, the seal on the sealing ring 42 and the feeding branch pipe 47 is released, and the internal passage of the feeding main pipe 41 is opened, and the organic phase can be smoothly fed into the open extraction tank 1 through the feeding branch pipe 47 to complete the automatic feeding.

[0072] Furthermore, as the organic phase is gradually injected, the liquid level will rise accordingly. The float 24 will continuously drive the trigger tooth plate 27 to move upward. The trigger gear 33 will continuously drive the first half gear 32 to rotate counterclockwise through the key rod 31. When the first half gear 32 disengages from the transmission gear 35 during rotation, the sealing plug 43 will slide to the left under the elastic force of the return spring 45, resealing the sealing ring 42 and the feeding branch pipe 47, and stopping the injection of organic phase into the pool.

[0073] In this embodiment, alkaline leaching solution is first injected into the open extraction tank 1. After the liquid level rises to the preset first fixed liquid level, the organic phase feeding channel is automatically opened. When the liquid level rises to the second limited liquid level as the organic phase is injected, the feeding of the organic phase is automatically stopped. The two liquid level heights are locked by the cooperation of the first half gear 32 and the transmission gear 35. The volume of alkaline leaching solution and organic phase can be fixed proportionally to achieve the required ratio for the extraction process. The feeding ratio of each batch of materials is consistent, which completely avoids fluctuations in the extraction conditions caused by human feeding deviation and ensures uniform lithium extraction reaction conditions.

[0074] The equipment strictly follows the operating sequence of adding alkaline leachate first, followed by organic phase. The feeding channel can only be unlocked after the aqueous phase level reaches the standard. If there is not enough liquid in the tank, the organic phase feeding channel will always be closed. This effectively prevents erroneous operations such as adding organic phase before aqueous phase or organic phase coming into direct contact with high concentration of alkali in advance. It also avoids premature hydrolysis and failure of the extractant due to excessive local alkalinity, automatically realizing the feeding sequence of "water first, oil later" and eliminating erroneous operations.

[0075] Second embodiment:

[0076] Please see Figures 9 to 11 A pH detection interlocking mechanism 5 is rotatably connected to the back side of the inner wall of the open extraction tank 1. The pH detection interlocking mechanism 5 includes a second rotating rod 51 rotatably connected to the back side of the inner wall of the open extraction tank 1. The second rotating rod 51 is located at the bottom of the key rod 31. A second half gear 52 is fixedly provided on the circumferential side of the second rotating rod 51. The second half gear 52 meshes with the trigger gear 33. A rotating bracket 53 is fixedly provided at the front end of the second rotating rod 51. A pH detector 54 is vertically arranged inside the rotating bracket 53.

[0077] The back of the open extraction tank 1 is fixedly provided with a multi-condition pointer display mechanism 6. The multi-condition pointer display mechanism 6 includes a mounting plate 61 fixedly provided on the back of the open extraction tank 1. A display plate 62 is fixedly provided on the back of the mounting plate 61. The rear end of the key rod 31 passes through the front of the mounting plate 61 and the display plate 62 in sequence and extends to the back of the display plate 62. A display pointer 63 is fixedly provided on the rear end of the key rod 31.

[0078] Preferably, in the initial stage of injecting alkaline leachate into the extraction tank, pH detector 54 is immersed in the liquid phase to output pH signal. Only when the detected pH value is stable above 14 (reaching the strongly alkaline conditions required by the process) is the subsequent automatic feeding of organic phase allowed. If the pH value does not meet the standard, the feeding of organic phase is prohibited. The pH value of alkaline leachate is adjusted by dropper 13 and dropper 14. Organic phase can be fed only after the process requirements are met, thereby ensuring that the extraction reaction is carried out under the correct alkaline conditions and avoiding the decrease in lithium extraction rate or the deterioration of selectivity due to insufficient pH.

[0079] Please combine Figure 9 and Figure 10 : An alkaline leachate after pH adjustment is injected into the open extraction tank 1. As the liquid level gradually rises, the buoyancy causes the float 24 to slide upward along the slide rail 21. The float 24 will drive the trigger tooth plate 27 to move upward synchronously. The upward movement of the trigger tooth plate 27 will drive the trigger gear 33 to rotate counterclockwise. The counterclockwise rotation of the trigger gear 33 will then drive the second rotating rod 51, the rotating bracket 53 and the pH detector 54 to rotate clockwise through the second half gear 52, thereby causing the bottom of the pH detector 54 to detach from the alkaline leachate.

[0080] Furthermore, in the initial stage, the second half gear 52 meshes with the trigger gear 33, while the first half gear 32 does not mesh with the transmission gear 35. When the trigger tooth plate 27 moves upward and drives the trigger gear 33 to rotate counterclockwise, the trigger gear 33 will first drive the second half gear 52 to rotate, detaching the bottom of the pH detector 54 from the alkaline leaching solution. Then, as the trigger gear 33 continues to rotate, the key rod 31 drives the first half gear 32 to mesh with the transmission gear 35. Only through the rotation of the transmission gear 35 can the organic phase be introduced.

[0081] In summary, when the liquid level rises to a predetermined height (usually corresponding to the first liquid level or the critical point when the organic phase is about to be injected), the pH detector 54 automatically rotates clockwise and rises with the rotating bracket 53, so that its bottom end is completely removed from the liquid surface.

[0082] Organic phases containing HBL121 extractant have low density and high viscosity, which can easily adhere to the surface of pH electrodes to form an oil film, leading to sluggish electrode response, measurement distortion, or even failure. Actively lifting the pH detector 54 off the liquid surface before the organic phase is injected can avoid contact between the electrode and the organic phase, extend its service life, and reduce the frequency of cleaning and maintenance.

[0083] Please combine Figure 11 When the float 24 moves the trigger tooth plate 27 upward, causing the trigger gear 33 to rotate counterclockwise, the trigger gear 33 will simultaneously drive the key lever 31 to rotate, and the rotation of the key lever 31 will in turn drive the display pointer 63 to rotate.

[0084] Furthermore, the display pointer 63 is coaxially fixed to the trigger gear 33 via the key rod 31, and its rotation angle corresponds to the lifting displacement of the float 24 (i.e., the liquid level height). Since the rotation of the trigger gear 33 is simultaneously controlled by the trigger tooth plate 27 and maintains mechanical cooperation with the first half gear 32 and the second half gear 52, the display pointer 63 can intuitively and in real time reflect the current liquid level height, the status of the pH detector 54, and the rate of organic phase addition.

[0085] In this embodiment, during the initial stage of injecting alkaline leachate into the extraction tank, pH detector 54 is immersed in the liquid phase and continuously outputs pH signal. Only when the detection value is stable at the strongly alkaline conditions required by the process is the subsequent automatic feeding action of organic phase allowed, which can ensure that the extraction alkalinity meets the standard and ensure the selectivity of lithium extraction.

[0086] When the liquid level rises to a predetermined height (the first liquid level or the critical point at which the organic phase is about to be injected), the trigger gear 33 rotates counterclockwise. Through the transmission of the second half gear 52, the second rotating rod 51, and the rotating bracket 53, the pH detector 54 rotates clockwise and is lifted, with its bottom completely detached from the liquid surface. This allows the pH detector 54 to be actively lifted off the liquid surface before the organic phase is injected, fundamentally avoiding contact between the electrode and the organic phase and preventing the organic phase from contaminating the electrode.

[0087] Third embodiment:

[0088] Please see Figure 1 , Figure 2 and Figure 12 The open extraction tank 1 has multiple fixed supports 7 fixed on its back side. The inner side of the multiple fixed supports 7 is provided with a liquid inlet main pipe 8. The liquid inlet main pipe 8 is connected to the feeding branch pipe 47. The surface of the liquid inlet main pipe 8 is connected with multiple liquid inlet branch pipes 9.

[0089] A mixing mechanism 10 is fixedly installed on the top of the open extraction tank 1. The mixing mechanism 10 includes a mounting bracket 101 fixedly installed on the top of the open extraction tank 1. A mixing shaft 102 is vertically arranged inside the mounting bracket 101. A plurality of mixing paddles 103 are arranged on the peripheral side of the mixing shaft 102. A mixing motor 104 for driving the mixing shaft 102 to rotate is arranged on the top of the mounting bracket 101.

[0090] The open extraction tank 1 has two feed pipes 11 connected to its left side, and a discharge pipe 12 connected to the bottom of the front side of the open extraction tank 1. Two droppers 13 are arranged longitudinally on the inner side of the open extraction tank 1, and multiple drip heads 14 are connected to the bottom of each of the two droppers 13.

[0091] Preferably, the inlet branch pipe 9 is located below the liquid surface;

[0092] Preferably, when the pH detector 54 detects that the pH value of the liquid phase does not meet the process requirements, the external control system or manual operation can add alkaline solution to the tank through the dripper 13 and the dripper 14 until the pH value stabilizes and meets the requirements.

[0093] Please combine Figure 12 Start the mixing motor 104. The rotation of the mixing motor 104 drives the mixing shaft 102 and the mixing paddle 103 to rotate. The rotation of the mixing paddle 103 mixes the organic phase and the alkaline leachate.

[0094] In this embodiment, the mixing shaft 102 drives multiple mixing paddles 103 to rotate at high speed, which forcibly stirs and mixes the organic phase and alkaline leachate in the open extraction tank 1. With the mechanical stirring action, the organic phase is dispersed into a large number of tiny droplets, which are uniformly suspended in the aqueous phase, increasing the specific surface area of ​​the two phases and shortening the mass transfer path of lithium ions from the aqueous phase to the organic phase.

[0095] In another application, the organic phase extraction lithium extraction equipment can also be used in the fields of environmental protection and water treatment, such as pH neutralization and adjustment in sewage treatment, the ratio of coagulant to sewage in coagulation and sedimentation processes, or the quantitative addition of disinfectant. It can be monitored in real time using pH detector 54, and the next stage of feeding is prohibited before the standard is met to ensure the treatment effect. The liquid level detection and dosing are completed automatically by the whole machine. It is suitable for field sewage treatment plants or remote factory areas, and has strong anti-clogging ability. The frustum-shaped sealing plug 43 is not sensitive to a small amount of suspended matter in the agent and is not easy to get stuck.

[0096] The present invention also provides a method for selectively extracting lithium from waste aluminum electrolytic slag.

[0097] Please see Figure 13 A method for selectively extracting lithium from waste aluminum electrolytic slag includes the following steps:

[0098] Step S1: Crush, grind, and dry the waste aluminum electrolytic slag to obtain fine-grained raw materials;

[0099] Step S2: After mixing the fine-particle raw material with aluminum sulfate, the mixture is calcined to convert the insoluble sodium lithium cryolite into soluble lithium sulfate. At the same time, fluorine combines with aluminum to form aluminum fluoride, thus achieving the initial solidification of fluorine.

[0100] Step S3: Leach the roasted product with water and filter to separate it, to obtain a leachate containing lithium and sodium and a leachate containing aluminum fluoride and aluminum oxide.

[0101] Step S4: Adjust the pH of the lithium and sodium leachate to strong alkalinity, and use an organic phase containing HBL121 extractant for extraction to selectively extract lithium;

[0102] Step S5: The supported organic phase is back-extracted in the aqueous phase using carbon dioxide as the stripping agent to obtain a back-extracting solution rich in lithium bicarbonate.

[0103] Step S6: Heat the back-extraction solution to decompose it, so that lithium bicarbonate is converted into lithium carbonate precipitate. After filtration, washing and drying, battery-grade lithium carbonate product is obtained.

[0104] Step S7: Evaporate and concentrate the raffinate after extraction, cool and crystallize to obtain sodium sulfate by-product, and return the mother liquor to the water leaching process for recycling;

[0105] Step S8: Mix the leaching residue containing aluminum fluoride and aluminum oxide with concentrated sulfuric acid to carry out an acid hydrolysis reaction, so that the aluminum oxide is converted into aluminum sulfate. After water leaching and filtration, an aluminum sulfate solution and aluminum fluoride solid that can be recycled back to the roasting process are obtained.

[0106] Preferably, in step S1, the waste aluminum electrolytic slag is crushed and ground to a particle size of less than 180 μm, and then dried for later use.

[0107] Preferably, in step S2, the waste aluminum electrolytic slag and aluminum sulfate (Al2(SO4)3) are mixed evenly at a mass ratio of 1:0.89 to 1:1.20, placed in a calcining furnace, and calcined at 450 to 600°C for 20 to 30 minutes to convert the lithium in the insoluble sodium lithium cryolite (Na2LiAlF6) into soluble lithium sulfate (Li2SO4), while fluorine combines with aluminum to form aluminum fluoride (AlF3), thus achieving the initial solidification of fluorine;

[0108] Preferably, in step S3, the calcined product is leached in water for 10 to 20 minutes at a liquid-to-solid ratio of 2:1 to 8:1 (mL / g) and a temperature of 20 to 60°C, and then filtered to obtain a leaching solution containing lithium and sodium and a leaching residue containing aluminum fluoride and aluminum oxide.

[0109] Preferably, in step S4, the pH of the lithium and sodium leaching solution is adjusted to above 14, and extraction is performed using an organic phase containing HBL121 extractant to selectively extract lithium. The extraction conditions are: HBL121 (p-tert-octylphenyl phosphate) volume concentration 20% to 40%, pH > 14, organic phase to aqueous phase volume ratio (O / A) 1:2 to 2:1, and mixing time 1 to 5 minutes.

[0110] Preferably, in step S5, the loaded organic phase is back-extracted in an aqueous phase using carbon dioxide (CO2) as the stripping agent. The back-extraction conditions are as follows: deionized water is used as the aqueous phase, the volume ratio of organic phase to aqueous phase (O / A) is 4:1, the CO2 flow rate is 100-200 mL / min, the reaction time is 30-60 minutes, and the temperature is 20-30℃, to obtain a back-extraction solution rich in lithium bicarbonate (LiHCO3).

[0111] Preferably, in step S6, the back-extraction solution is heated at 90-95°C for 30-60 minutes to decompose lithium bicarbonate into lithium carbonate (Li2CO3) precipitate, which is then filtered, washed, and dried to obtain battery-grade lithium carbonate product.

[0112] Preferably, in step S7, the raffinate is evaporated, concentrated, cooled and crystallized to obtain sodium sulfate (Na2SO4) byproduct, and the mother liquor is returned to the water leaching process for recycling;

[0113] Preferably, in step S8, the obtained leaching residue containing aluminum fluoride and aluminum oxide is subjected to acid hydrolysis treatment. Specifically, the leaching residue is mixed with concentrated sulfuric acid at a mass ratio of 1:1.5 to 1:2.5, and the acid hydrolysis reaction is carried out at 150 to 250°C for 60 to 120 minutes. The aluminum oxide is converted into aluminum sulfate. The solid product after acid hydrolysis is leached with water, filtered to obtain aluminum sulfate solution and aluminum fluoride solid. The solution can be recycled as a roasting additive.

[0114] In this embodiment, waste aluminum electrolytic slag, which is hazardous solid waste, is converted into lithium extraction raw material, realizing the resource utilization and high value of solid waste. By selectively extracting lithium and preparing battery-grade lithium carbonate products, not only are key metal materials obtained from solid waste, but sodium and aluminum are also recovered simultaneously, enabling the cascade utilization of multiple valuable components. At the same time, the roasting process stabilizes fluorine in aluminum fluoride, significantly reducing the leaching toxicity of the waste residue and achieving the harmless treatment of solid waste. The aluminum sulfate solution and water leaching mother liquor obtained from acid hydrolysis can be returned to the previous process for recycling, forming a closed-loop clean process, significantly reducing the consumption of external reagents and secondary pollution.

[0115] Please refer to the reference again. Figures 1 to 12 The working principle of the organic phase extraction lithium extraction equipment provided by this invention is as follows:

[0116] Step S1: The alkaline leachate after pH adjustment is injected into the open extraction tank 1. As the liquid level gradually rises, the buoyancy causes the float 24 to slide upward along the slide rail 21. The float 24 will drive the trigger tooth plate 27 to move upward synchronously. The upward movement of the trigger tooth plate 27 will drive the trigger gear 33 to rotate counterclockwise. The counterclockwise rotation of the trigger gear 33 will then drive the second rotating rod 51, the rotating bracket 53 and the pH detector 54 to rotate clockwise through the second half gear 52, so that the bottom end of the pH detector 54 is removed from the alkaline leachate.

[0117] In step S2, after the bottom of the pH detector 54 is removed from the alkaline leaching solution, the trigger tooth plate 27 continues to move upward, causing the trigger gear 33 to rotate counterclockwise. This will drive the key rod 31 and the first half gear 32 to rotate counterclockwise synchronously. When the first half gear 32 rotates counterclockwise to the meshing position, it meshes with the upper transmission gear 35, which will drive the transmission gear 35 to rotate clockwise, causing the first rotating rod 34 to drive the swing bracket 36 to swing clockwise.

[0118] The swing bracket 36 has an inclined groove adapted to the drive bracket 46. When it swings clockwise, it will push the drive bracket 46 and the sliding rod 44 to the right with the help of the inclined groove, thereby pulling the sealing plug 43 to the right and compressing the reset spring 45. By moving the sealing plug 43 to the right, the seal on the sealing ring 42 and the feeding branch pipe 47 is released, and the internal passage of the feeding main pipe 41 is opened, and the organic phase can be smoothly fed into the open extraction tank 1 through the feeding branch pipe 47 to complete the automatic feeding.

[0119] In step S3, as the organic phase is gradually injected, the liquid level will rise accordingly. The float 24 will continuously drive the trigger tooth plate 27 to move upward. The trigger gear 33 will continuously drive the first half gear 32 to rotate counterclockwise through the key rod 31. When the first half gear 32 disengages from the transmission gear 35 during rotation, the sealing plug 43 will slide to the left under the elastic force of the reset spring 45, resealing the sealing ring 42 and the feeding branch pipe 47, and stopping the injection of organic phase into the pool.

[0120] In step S4, when the float 24 moves the trigger tooth plate 27 upward, causing the trigger gear 33 to rotate counterclockwise, the trigger gear 33 will simultaneously drive the key lever 31 to rotate, and the rotation of the key lever 31 will in turn drive the display pointer 63 to rotate.

[0121] The display pointer 63 is coaxially fixed to the trigger gear 33 via the key rod 31. Its rotation angle corresponds to the lifting displacement of the float 24 (i.e., the liquid level). Since the rotation of the trigger gear 33 is simultaneously controlled by the trigger tooth plate 27 and maintains mechanical cooperation with the first half gear 32 and the second half gear 52, the display pointer 63 can intuitively and in real time reflect the current liquid level, the status of the pH detector 54, and the rate of organic phase addition.

[0122] In step S5, when adding the organic phase to the alkaline leachate, the mixing motor 104 is started. The rotation of the mixing motor 104 drives the mixing shaft 102 and the mixing paddle 103 to rotate. The rotation of the mixing paddle 103 is used to mix the organic phase and the alkaline leachate, thereby increasing the specific surface area of ​​the two phases in contact.

[0123] 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 organic phase extraction lithium extraction device, characterized in that, This includes an open extraction tank, a float triggering mechanism, a drive mechanism, and a feeding and opening / closing mechanism; The float triggering mechanism includes a slide rail fixed to the back of the inner wall of the open extraction tank. A sliding seat is slidably connected to the circumferential side of the slide rail. A sliding bracket is fixed to the front of the sliding seat. A float is fixed to the front of the sliding bracket. Two adjusting bolts are fixed to the front of the slide rail. Limiting brackets are fixed to the surfaces of the two adjusting bolts. A triggering tooth plate is fixed to the left side of the float. The driving mechanism includes a key rod rotatably connected to the back of the inner wall of the open extraction tank. A first half gear is connected to the key groove on the peripheral side of the key rod. A trigger gear is fixed at the front end of the key rod. The trigger gear meshes with a trigger tooth plate. A first rotating rod is rotatably connected to the back of the inner wall of the open extraction tank and located at the top of the key rod. A transmission gear is fixed on the peripheral side of the first rotating rod. A swing bracket is fixed at the front end of the first rotating rod. The feeding opening and closing mechanism includes a feeding main pipe fixed inside the open extraction tank. A sealing ring is fixed on the inner wall of the feeding main pipe. A sealing plug is slidably connected to the inner wall of the feeding main pipe and inside the sealing ring. A sliding rod is fixed on the right side of the sealing plug. The circumferential side of the sliding rod is slidably connected to the inside of the feeding main pipe. A return spring is sleeved on the circumferential side of the sliding rod and inside the feeding main pipe. A drive bracket is fixed at the right end of the sliding rod. A swing bracket is sleeved on the circumferential side of the drive bracket. A feeding branch pipe is connected to the bottom of the feeding main pipe and the bottom of the sealing plug.

2. The organic phase extraction lithium extraction equipment according to claim 1, characterized in that, During the counterclockwise rotation of the first half gear, it will mesh with the transmission gear and drive the transmission gear to rotate clockwise. The left side of the sealing plug is frustoconical and the right side is cylindrical. The sealing plug seals the sealing ring through the frustoconical design on the left side and seals the feeding branch pipe through the cylindrical design on the right side.

3. The organic phase extraction lithium extraction equipment according to claim 1, characterized in that, The swing bracket has an inclined groove inside that works with the drive bracket. When the swing bracket rotates clockwise, the inclined groove will pull the sealing plug to the right through the drive bracket and the sliding rod, thus canceling the seal on the sealing ring and the feeding branch pipe.

4. The organic phase extraction lithium extraction equipment according to claim 1, characterized in that, A pH detection interlocking mechanism is rotatably connected to the back side of the inner wall of the open extraction tank. The pH detection interlocking mechanism includes a second rotating rod rotatably connected to the back side of the inner wall of the open extraction tank. The second rotating rod is located at the bottom of the key rod. A second half gear is fixed on the circumferential side of the second rotating rod. The second half gear meshes with a trigger gear. A rotating bracket is fixed on the front end of the second rotating rod. A pH detector is vertically arranged inside the rotating bracket.

5. The organic phase extraction lithium extraction equipment according to claim 1, characterized in that, A multi-condition pointer display mechanism is fixedly provided on the back of the open extraction tank. The multi-condition pointer display mechanism includes a mounting plate fixedly provided on the back of the open extraction tank, a display plate fixedly provided on the back of the mounting plate, the rear end of the key rod passing through the front of the mounting plate and the display plate in sequence and extending to the back of the display plate, and a display pointer fixedly provided on the rear end of the key rod.

6. The organic phase extraction lithium extraction equipment according to claim 1, characterized in that, The back of the open extraction tank is fixed with multiple fixed supports, and the inner side of the multiple fixed supports is provided with a liquid inlet main pipe. The liquid inlet main pipe is connected to the feeding branch pipe, and the surface of the liquid inlet main pipe is connected with multiple liquid inlet branch pipes.

7. The organic phase extraction lithium extraction equipment according to claim 1, characterized in that, A mixing mechanism is fixedly installed on the top of the open extraction tank. The mixing mechanism includes a mounting bracket fixed to the top of the open extraction tank. A mixing shaft is vertically arranged inside the mounting bracket. Multiple mixing paddles are arranged on the circumferential side of the mixing shaft. A mixing motor for driving the mixing shaft to rotate is arranged on the top of the mounting bracket.

8. The organic phase extraction lithium extraction equipment according to claim 1, characterized in that, The open extraction tank has two feed pipes connected to its left side, a discharge pipe connected to the bottom of its front side, and two droppers arranged longitudinally on the inner side of the open extraction tank, each dropper having multiple drip heads connected to its bottom.

9. A method for selectively extracting lithium from waste aluminum electrolytic slag, characterized in that, Includes the following steps: Step S1: Crush, grind, and dry the waste aluminum electrolytic slag to obtain fine-grained raw materials; Step S2: After mixing the fine-particle raw material with aluminum sulfate, the mixture is calcined to convert the insoluble sodium lithium cryolite into soluble lithium sulfate. At the same time, fluorine combines with aluminum to form aluminum fluoride, thus achieving the initial solidification of fluorine. Step S3: Leach the roasted product with water and filter to separate it, to obtain a leachate containing lithium and sodium and a leachate containing aluminum fluoride and aluminum oxide. Step S4: Adjust the pH of the lithium and sodium leaching solution to strong alkalinity, and use an organic phase containing HBL121 extractant for extraction to selectively extract lithium. The selective lithium extraction should be carried out in the organic phase extraction lithium extraction equipment as described in claims 1-8. Step S5: The supported organic phase is back-extracted in the aqueous phase using carbon dioxide as the stripping agent to obtain a back-extracting solution rich in lithium bicarbonate. Step S6: Heat the back-extraction solution to decompose it, so that lithium bicarbonate is converted into lithium carbonate precipitate. After filtration, washing and drying, battery-grade lithium carbonate product is obtained. Step S7: Evaporate and concentrate the raffinate after extraction, cool and crystallize to obtain sodium sulfate by-product, and return the mother liquor to the water leaching process for recycling; Step S8: Mix the leaching residue containing aluminum fluoride and aluminum oxide with concentrated sulfuric acid to carry out an acid hydrolysis reaction, so that the aluminum oxide is converted into aluminum sulfate. After water leaching and filtration, an aluminum sulfate solution and aluminum fluoride solid can be recycled back to the roasting process.

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