Equipment for extracting lithium from electrolytic aluminum slag and process for extracting lithium and co-producing cryolite

Abstract

The invention provides equipment for extracting lithium from electrolytic aluminum slag and a process for extracting lithium and co-producing cryolite, and relates to the technical field of solid waste treatment, the equipment comprises a bottom plate, a heating tank, an extracting tank, a filtering tank, a top cover, a driving mechanism, a switching mechanism and a mixing mechanism; the heating tank is installed on the upper surface of the bottom plate, the extraction tank is installed inside the heating tank, the filtering tank is installed inside the extraction tank, the top cover is installed on the upper surface of the filtering tank in a sealed mode, and a liquid inlet pipe and a feeding pipe are installed inside the top cover. According to the scheme, the conical mixing barrel and the linkage overturning type material mixing plate are adopted, the material mixing plate can overturn caustic soda flakes into the electrolytic aluminum slag, then the caustic soda flakes and the electrolytic aluminum slag are mixed through the material mixing rod, it can be guaranteed that the caustic soda flakes can be evenly mixed with the electrolytic aluminum slag through the design, and it is guaranteed that the caustic soda flakes can be well attached to the surface of the electrolytic aluminum slag; and rapid overheating can be avoided when the subsequent caustic soda flakes are contacted with water, so that the filter tank works more stably and safely.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and in particular to equipment for extracting lithium from electrolytic aluminum slag and a process for extracting lithium and producing cryolite. Background Art

[0002] Over 80% of the lithium carbonate needed by companies is imported, primarily due to limitations in resources, technology, mining conditions, and economics. This has led to a long-term slowdown in the industrialization of lithium carbonate in my country, far from meeting the needs of the rapidly developing new energy industry. In aluminum electrolysis, to improve current efficiency and reduce energy consumption, in addition to aluminum fluoride and cryolite, certain lithium-containing salts, such as fluorides or chlorides, are typically added to improve the properties of the electrolyte.

[0003] Electrolytic aluminum slag generates a significant amount of solid waste, with the total volume reaching 364,600 tons, equivalent to 3,646 to 9,844 tons of lithium. Proper recycling of this lithium resource would help alleviate the pressure on lithium demand from the new energy industry. This paper investigates the efficient recycling of low-grade lithium from electrolytic aluminum slag, exploring optimal process routes and parameters to improve product quality and maximize resource value.

[0004] Existing technologies for the treatment of electrolytic filter residue are very limited, especially during the alkalization and acid leaching processes. Traditional technologies mostly use partitioned and tank-based operations, which is very cumbersome and easily wastes processing time for lithium extraction. Secondly, during the lithium extraction process, caustic soda flakes and electrolytic filter residue need to be mixed. Traditional mixing methods are prone to cause fixed-point contact and overheating, which can be dangerous and affect the lithium extraction effect.

[0005] Therefore, it is necessary to provide a lithium extraction device from electrolytic aluminum slag and a lithium extraction and cryolite co-production process thereof to solve the above technical problems. Summary of the Invention

[0006] The present invention provides a device for extracting lithium from electrolytic aluminum slag and a process for extracting lithium and producing cryolite thereof, which solves the technical problems in the related art that the lithium extraction operation is cumbersome, takes too much time, and the mixing of caustic soda flakes easily causes overheating.

[0007] In order to solve the above technical problems, the present invention provides a lithium extraction device from electrolytic aluminum slag, comprising a bottom plate, a heating tank, an extraction tank, a filter tank, a top cover, a driving mechanism, a switching mechanism and a mixing mechanism; The heating tank is installed on the upper surface of the bottom plate, the extraction tank is installed inside the heating tank, the filter tank is installed inside the extraction tank, and the top cover is sealed and installed on the upper surface of the filter tank. The top cover is respectively installed with a liquid inlet pipe and a feed pipe; The driving mechanism includes a mounting base, a motor and a driving rod, wherein the mounting base is mounted on the upper surface of the top cover by bolts, the motor is mounted on the upper surface of the mounting base, the driving rod keyway is connected to the bottom output shaft of the motor, the outer wall of the driving rod is provided with a sliding sleeve, the outer wall of the sliding sleeve is threadedly connected with a positioning bolt, the bottom of the sliding sleeve is fixed with a first half gear, and the bottom of the first half gear is fixed with a second half gear; The upper and lower ends of the driving rod are rotatably connected to the mounting seat and the top cover; The switching mechanism includes a positioning seat, a first gear and a hollow tube. The positioning seat is mounted on the upper surface of the top cover and is located on one side of the mounting seat by bolts. The hollow tube is rotatably mounted on the axis of the top cover. The outer wall of the hollow tube and the internal keyway of the positioning seat are connected to the first gear. The mixing mechanism includes a mixing cylinder, a fixed plate and a mixing plate. The mixing cylinder is fixed to the inner wall of the filter tank, the fixed plate is fixed to the inner wall of the mixing cylinder, and the mixing plate is rotatably connected to the middle position of the fixed plate. The outer wall of the hollow tube and the internal keyway of the mixing cylinder are connected to the second bevel gear, the outer wall of the second bevel gear is meshed with the first bevel gear, and the outer wall of the hollow tube and the mixing rod are fixed below the second bevel gear.

[0008] Preferably, the positioning bolt extends to the outer wall of the driving rod, the first half gear and the second half gear are slidingly connected to the driving rod, and the first half gear and the second half gear are adapted to the first gear.

[0009] Preferably, the outlet end of the liquid inlet pipe is directly above the mixing plate, one side of the mixing plate is rotatably connected to the inner wall of the mixing barrel through a bearing, the cross-section of the mixing barrel is conical, and the axis of the first bevel gear is connected to the keyway of the mixing plate.

[0010] Preferably, it also includes an extraction mechanism; A first rotating ring is slidably connected to the outer wall of the driving rod and located above the sliding sleeve. A lifting plate is rotatably connected to the outer wall of the first rotating ring. A connecting rod is fixed to the top of the sliding sleeve. The interior of the positioning seat is rotatably connected to a third rotating ring, the internal keyway of the third rotating ring is connected to a key rod, the top end of the key rod is fixed with a top plate, the outer wall of the key rod is sleeved with a spring, and one side of the lifting plate and located above the top plate is rotatably connected to a second rotating ring; The extraction mechanism includes a sealing box fixedly mounted at the bottom end of the hollow tube, the interior of the sealing box is rotatably connected to two rotating shafts, the exteriors of the two rotating shafts are both mounted with extraction plates by bolts, the interior of the sealing box and at the axis centers of the two rotating shafts are both mounted with linkage plates, the interiors of the two linkage plates are both provided with notches, and the interior of the sealing box and at the bottom end of the key rod are fixed with a switching lever; A screw conveyor is installed at the bottom of the filter tank, a discharge pipe is installed at the bottom of the extraction tank, and an auxiliary rod is fixed at the bottom of the sealing box.

[0011] Preferably, the top end of the connecting rod is fixedly connected to the upper surface of the first swivel, and the axis of the second swivel is connected to the axis keyway of the top plate.

[0012] Preferably, the upper and lower ends of the spring are fixedly connected to the top plate and the third rotating ring, and the key rod and the hollow tube are slidably connected.

[0013] Preferably, it further includes a negative pressure mechanism; The negative pressure mechanism includes a third gear rotatably connected to the upper surface of the top cover, the top keyway of the third gear is connected to the first pulley, the upper surface of the top cover and located on one side of the third gear is rotatably connected to a rotating rod, the top keyway of the rotating rod is connected to the second pulley, the outer walls of the first pulley and the second pulley are sleeved with belts, the bottom end of the rotating rod and the keyway located inside the filter tank are connected to fan blades, the outer wall of the filter tank and located above the fan blades are fixed with an exhaust pipe, and one side of the third gear is meshed and connected to the second gear.

[0014] Preferably, the second half gear and the second gear are adapted to each other, the hollow tube passes through the axis of the second gear and does not contact the second gear, and the second gear is rotatably connected to the upper surface of the top cover.

[0015] The lithium extraction and cryolite production process includes the following steps: S1: electrolytic aluminum slag, water and caustic soda are reacted in a certain mass ratio at a certain temperature for a period of time, and then filtered to obtain a mixed washing liquid of sodium metaaluminate and sodium hydroxide and a filter residue; Specifically: Electrolytic aluminum slag, water and caustic soda are reacted in a mass ratio of 1:0.5-5:0.1-5 at a temperature of 25-95 degrees for 0.2-5 hours and filtered to obtain a sodium metaaluminate / sodium hydroxide mixed washing solution; S2: acid leaching is performed on the filter residue, water and concentrated sulfuric acid in a certain ratio. After a period of reaction at a certain temperature, a slurry containing a lithium solution is obtained and hydrofluoric acid gas is generated; Specifically: The filter residue, water and concentrated sulfuric acid are acid-leached in a ratio of 1:0.5~5:0.1~5 at a temperature of 25~95 degrees. After reacting for 0.2~9 hours, a slurry of lithium solution is obtained and hydrofluoric acid gas is generated. S1 and S2 need to complete the operation in the filter tank during the working process.

[0016] S3: subjecting the lithium solution-containing slurry to liquid-solid separation to obtain a lithium solution and crude cryolite; S4: adjusting the pH value of the lithium solution to 11-13 and then performing liquid-solid separation to obtain a lithium purified solution; S5: removing calcium ions and magnesium ions from the lithium purified solution using sodium carbonate and ion exchange resin to obtain a lithium purified solution; S6: The sodium aluminate / sodium hydroxide mixed washing solution in S1, the hydrofluoric acid gas in S2 and the crude cryolite produced in step S3 are mixed, and stirred at a certain temperature for 10 to 60 minutes to produce finished cryolite.

[0017] Compared with related technologies, the lithium extraction equipment from electrolytic aluminum slag and the lithium extraction and cryolite co-production process provided by the present invention have the following beneficial effects: Compared with traditional designs, this case is designed with a filter tank inside the extraction tank. The electrolytic aluminum slag is first alkalized inside the filter tank to separate the sodium aluminate / sodium hydroxide mixed washing liquid and the filter residue. Finally, the user can extract the sodium aluminate / sodium hydroxide mixed washing liquid and continue to acid leaching lithium in the filter tank. This design adopts an integrated design. Both steps can be carried out in one filter tank, effectively saving the user's operation time and thus improving the efficiency of lithium extraction. Secondly, in the process of lithium extraction, a conical mixing barrel and a linked flip-type mixing plate are used. The mixing plate can flip the caustic soda flakes into the electrolytic aluminum slag, and then the mixing rod mixes the caustic soda flakes and the electrolytic aluminum slag. This design can ensure that the caustic soda flakes can be evenly mixed with the electrolytic aluminum slag, ensure that the caustic soda flakes can be well attached to the surface of the electrolytic aluminum slag, and ensure that the subsequent caustic soda flakes can avoid rapid overheating when in contact with water, making the filter tank work more stable and safe. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 The best structural diagram provided by the present invention; Figure 2 for Figure 1 The schematic cross-sectional view of the heating tank and the extraction tube is shown; Figure 3 for Figure 2 The filter tank cross-sectional structure diagram shown; Figure 4 for Figure 1 Schematic diagram of the driving mechanism, switching mechanism and top cover position distribution shown; Figure 5 for Figure 4 Detailed connection structure diagram of the driving mechanism and the switching mechanism shown; Figure 6 for Figure 3 Schematic diagram of the mixing mechanism structure shown; Figure 7 for Figure 4 The schematic cross-sectional structure diagram of the first gear, the second gear and the hollow tube is shown; Figure 8 This is a schematic structural diagram of the hollow tube and extraction mechanism shown in the present invention; Figure 9 for Figure 8 The enlarged structural diagram of point A is shown; Figure 10 for Figure 9 Detailed structural diagram of the extraction mechanism shown; Figure 11 Schematic diagram of the detailed structure of the negative pressure mechanism shown in the present invention.

[0020] Description of Figure Numbers: 1. Bottom plate, 2. Heating tank, 3. Extraction tank, 4. Filter tank; 5. Driving mechanism, 51. Mounting seat, 52. Motor, 53. Driving rod, 54. Sliding sleeve, 55. Positioning bolt, 56. First half gear, 57. Second half gear, 58. Connecting rod, 59. Lifting plate, 510. First swivel, 511. Second swivel; 6. Switching mechanism, 61. Positioning seat, 62. Third rotating ring, 63. Key rod, 64. Spring, 65. Top plate, 66. Hollow tube, 67. First gear, 68. Second gear; 7. Extraction mechanism, 71. Sealing box, 72. Rotating shaft, 73. Linkage plate, 74. Extraction plate, 75. Notch, 76. Switching lever; 8. Mixing mechanism, 81. Mixing cylinder, 82. Fixed plate, 83. Mixing plate, 84. First bevel gear, 85. Second bevel gear, 86. Mixing rod; 9. Negative pressure mechanism, 91. Third gear, 92. First pulley, 93. Second pulley, 94. Belt, 95. Rotating rod, 96. Fan blade; 10. Liquid inlet pipe, 11. Feed pipe, 12. Exhaust pipe, 13. Screw conveyor, 14. Discharge pipe, 15. Auxiliary rod, 16. Top cover.

[0021] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] The present invention provides equipment for extracting lithium from electrolytic aluminum slag and a process for extracting lithium and producing cryolite.

[0024] First embodiment: See also Figures 1 to 6 , a lithium extraction device from electrolytic aluminum slag, comprising a bottom plate 1, a heating tank 2, an extraction tank 3, a filter tank 4, a top cover 16, a driving mechanism 5, a switching mechanism 6 and a mixing mechanism 8; The heating tank 2 is mounted on the upper surface of the bottom plate 1, the extraction tank 3 is mounted inside the heating tank 2, the filter tank 4 is mounted inside the extraction tank 3, and the top cover 16 is sealed and mounted on the upper surface of the filter tank 4. The top cover 16 is respectively installed with a liquid inlet pipe 10 and a feed pipe 11; The driving mechanism 5 includes a mounting base 51, a motor 52, and a driving rod 53. The mounting base 51 is mounted on the upper surface of the top cover 16 by bolts. The motor 52 is mounted on the upper surface of the mounting base 51. The driving rod 53 is keyway-connected to the bottom output shaft of the motor 52. A sliding sleeve 54 is sleeved on the outer wall of the driving rod 53. A positioning bolt 55 is threadedly connected to the outer wall of the sliding sleeve 54. A first half gear 56 is fixed to the bottom of the sliding sleeve 54. A second half gear 57 is fixed to the bottom of the first half gear 56. The upper and lower ends of the driving rod 53 are rotatably connected to the mounting base 51 and the top cover 16; The switching mechanism 6 includes a positioning seat 61, a first gear 67, and a hollow tube 66. The positioning seat 61 is mounted on the upper surface of the top cover 16 and is located on one side of the mounting seat 51 by bolts. The hollow tube 66 is rotatably mounted on the axis of the top cover 16. The outer wall of the hollow tube 66 and the internal keyway of the positioning seat 61 are connected to the first gear 67. Preferably, the motor 52 can be preferably a three-phase asynchronous motor.

[0025] See also Figure 4 and Figure 5 : The starting motor 52 can control the driving rod 53 to rotate clockwise or counterclockwise; When the driving rod 53 rotates, it will drive the sliding sleeve 54, the first half gear 56 and the second half gear 57 to rotate synchronously. First, when the tooth surface of the second half gear 57 rotates to the tooth surface of the first gear 67, the second half gear 57 will rotate and engage to control the rotation of the first gear 67. When the toothless surface of the second half gear 57 rotates to the first gear 67, the second half gear 57 will not engage to transmit the first gear 67, and at this time, the tooth surface of the first half gear 56 will rotate to engage to transmit and control the rotation of the first gear 67. Therefore, whether the driving rod 53 rotates clockwise or counterclockwise, the first half gear 56 and the second half gear 57 will engage to transmit and intermittently control the rotation of the first gear 67.

[0026] The mixing mechanism 8 includes a mixing cylinder 81, a fixed plate 82 and a mixing plate 83. The mixing cylinder 81 is fixed to the inner wall of the filter tank 4, the fixed plate 82 is fixed to the inner wall of the mixing cylinder 81, and the mixing plate 83 is rotatably connected to the middle position of the fixed plate 82. The outer wall of the hollow tube 66 and the internal keyway of the mixing cylinder 81 are connected to the second bevel gear 85, and the outer wall of the second bevel gear 85 is meshed with the first bevel gear 84. The outer wall of the hollow tube 66 and the mixing rod 86 are fixed below the second bevel gear 85.

[0027] See also Figure 5 and Figure 6 : When the first gear 67 rotates, the first gear 67 will rotate and drive the control hollow tube 66 to rotate at the center position of the top cover 16. Secondly, during the rotation of the hollow tube 66, the second bevel gear 85 and the mixing rod 86 will rotate synchronously. During the rotation of the second bevel gear 85, the first bevel gear 84 is engaged and driven to drive the mixing plate 83 to rotate in the fixed plate 82.

[0028] The positioning bolt 55 extends to the outer wall of the driving rod 53 , the first half gear 56 and the second half gear 57 are slidably connected to the driving rod 53 , and the first half gear 56 and the second half gear 57 are adapted to the first gear 67 .

[0029] The outlet end of the liquid inlet pipe 10 is directly above the mixing plate 83. One side of the mixing plate 83 is rotatably connected to the inner wall of the mixing cylinder 81 through a bearing. The cross-section of the mixing cylinder 81 is conical, and the axis of the first bevel gear 84 is connected to the keyway of the mixing plate 83.

[0030] The working principle of this embodiment is as follows: S1: Mix the electrolytic aluminum slag, water and caustic soda in a mass ratio of 1:0.5-5:0.1-5 in the filter tank 4. The electrolytic filter residue needs to be fed from the feed pipe 11 into the mixing drum 81. The caustic soda and water need to be fed from the liquid inlet pipe 10 into the mixing drum 81. The order of feeding needs to be that the caustic soda enters first and then the water. The user starts the motor 52 to control the driving rod 53 to drive the first half gear 56 and the second half gear 57 to rotate. During the rotation, the first half gear 56 and the second half gear 57 intermittently control the first gear 67 to control the hollow tube 66 to rotate. During the rotation, the mixing rod 86 rotates the electrolytic aluminum slag, and the mixing plate 83 rotates to mix the caustic soda flakes with the electrolytic aluminum slag. S2: Start the heating tank 2 to heat the extraction tank 3, control the temperature at 25-95 degrees, react for 0.2-5 hours, filter, and obtain a sodium aluminate / sodium hydroxide mixed washing solution and a filter residue. The sodium aluminate / sodium hydroxide mixed washing solution in the extraction tank 3 is discharged through the discharge pipe 14, and the filter residue remains in the filter tank 4; S3: Finally, water and concentrated sulfuric acid are acid-leached in the filter residue inside the filter tank 4 in a ratio of 1:0.5-5:0.1-5 at a temperature of 25-95 degrees Celsius for 0.2-9 hours to obtain a lithium solution slurry and generate hydrofluoric acid gas; S4: Finally, the discharge pipe 14 discharges the lithium solution in the extraction tank 3, and the screw conveyor 13 is started to transmit and discharge the filter residue in the filter tank 4. This embodiment

[0031] Compared with the traditional design, this case is designed with a filter tank 4 inside the extraction tank 3. The electrolytic aluminum slag is first alkalized inside the filter tank 4 to separate the sodium aluminate / sodium hydroxide mixed washing liquid and the filter residue. Finally, the user can extract the sodium aluminate / sodium hydroxide mixed washing liquid and continue to acid leaching lithium in the filter tank 4. This design adopts an integrated design. Both steps can be performed in one filter tank 4, which effectively saves the user's operation time and thus improves the efficiency of lithium extraction. Secondly, in the process of lithium extraction, a conical mixing barrel 81 and a linked flip-type mixing plate 83 are used. The mixing plate 83 can flip the caustic soda flakes into the electrolytic aluminum slag, and then the mixing rod 86 mixes the caustic soda flakes and the electrolytic aluminum slag. This design can ensure that the caustic soda flakes can be evenly mixed with the electrolytic aluminum slag, ensure that the caustic soda flakes can be well attached to the surface of the electrolytic aluminum slag, and ensure that the subsequent caustic soda flakes can avoid rapid overheating when in contact with water, making the filter tank 4 work more stable and safe.

[0032] Second embodiment: See also Figure 5 、 Figures 7 to 10 , further comprising an extraction mechanism 7; A first rotating ring 510 is slidably connected to the outer wall of the driving rod 53 and located above the sliding sleeve 54. A lifting plate 59 is rotatably connected to the outer wall of the first rotating ring 510. A connecting rod 58 is fixed to the top of the sliding sleeve 54. The positioning seat 61 is internally connected to a third swivel 62, and the internal keyway of the third swivel 62 is connected to a key rod 63. A top plate 65 is fixed to the top of the key rod 63, and a spring 64 is sleeved on the outer wall of the key rod 63. A second swivel 511 is rotatably connected to one side of the lifting plate 59 and located above the top plate 65. The extraction mechanism 7 includes a sealing box 71 fixed to the bottom end of the hollow tube 66. The interior of the sealing box 71 is rotatably connected to two rotating shafts 72. The exteriors of the two rotating shafts 72 are both fixed with extraction plates 74 by bolts. The interior of the sealing box 71 is provided with linkage plates 73 located at the axis centers of the two rotating shafts 72. The interiors of the two linkage plates 73 are provided with notches 75. A switching lever 76 is fixed to the interior of the sealing box 71 and located at the bottom end of the key rod 63. A screw conveyor 13 is installed at the bottom of the filter tank 4 , a discharge pipe 14 is installed at the bottom of the extraction tank 3 , and an auxiliary rod 15 is fixed at the bottom of the sealing box 71 .

[0033] See also Figure 5 During operation of the first embodiment, the user can slide the sleeve 54 downward to slide the first half gear 56 and the second half gear 57 downward. When the second half gear 57 moves downward, the second half gear 57 engages with the second gear 68, and the first half gear 56 moves to the initial position of the second half gear 57. See also Figure 5 and Figure 6 : When the sliding sleeve 54 moves downward, it synchronously drives the connecting rod 58 to control the first rotating ring 510 and the lifting plate 59 to move downward. When the lifting plate 59 moves downward, the second rotating ring 511 will control the top plate 65 to compress the spring 64. When the top plate 65 moves downward, it will control the key rod 63 to move downward in the vertical direction of the hollow tube 66.

[0034] See also Figure 8 and Figure 9 : The key rod 63 will control the switching rod 76 to descend in conjunction during the descending process. The switching rod 76 will be subjected to force on two notches 75 during the descending process. When the notches 75 are subjected to force, the oblique direction linkage plate 73 will be controlled to flip the control shaft 72 to rotate in the sealing box 71, thereby controlling the extraction plate 74 to switch the oblique direction to the horizontal direction.

[0035] The top end of the connecting rod 58 is fixedly connected to the upper surface of the first rotating ring 510 , and the axis of the second rotating ring 511 is connected to the axis keyway of the top plate 65 .

[0036] The upper and lower ends of the spring 64 are fixedly connected to the top plate 65 and the third rotating ring 62 , and the key rod 63 is slidably connected to the hollow tube 66 .

[0037] Preferably, the horizontal cross-section of the switching rod 76 is a Z-shaped structure, and the switching rod 76 passes through the interiors of the two notches 75 .

[0038] The working principle of this embodiment is as follows: S1: During the operation of the first embodiment, the user needs to first loosen the positioning bolt 55 during pickling operation, and then slide the sleeve 54 to move the first half gear 56 and the second half gear 57 downward. The second half gear 57 meshes with the second gear 68. At this time, only the first half gear 56 can mesh with the first gear 67 to control its rotation. S2: When the sliding sleeve 54 moves downward, the lifting plate 59 is linked to the control key rod 63 to move downward. The key rod 63 can control the switching rod 76 to control the extraction plate 74 to switch the tilt state to the horizontal state; S3: At this time, when the user starts the motor 52, the first half gear 56 can be controlled to engage with the first gear 67 to rotate. The first gear 67 drives the hollow tube 66 to rotate. During the rotation of the hollow tube 66, the key rod 63 is synchronously driven to rotate, and finally the extraction plate 74 is rotated to acid-leach the lithium in the filter tank 4.

[0039] It can be understood that: due to the rotation of the first swivel 510 and the lifting plate 59, the lifting and lowering of the sleeve 54 will not affect the rotation of the driving rod 53 controlling the first swivel 510, the connecting rod 58 and the sleeve 54. Secondly, the second swivel 511, the third swivel 62 and the lifting plate 59 and the positioning seat 61 are rotationally connected. Therefore, when the key rod 63 is in the process of descending, it will not affect the first gear 67 controlling the rotation of the key rod 63 and the hollow tube 66. This embodiment

[0040] Compared to the traditional design, in this case, during the acid leaching process of lithium extraction, the user can slide the first half gear 56 and the second half gear 57 downward, and the second half gear 57 is disengaged from the first gear 67. The first gear 67 is only engaged through the first half gear 56. Under the condition of the same rotation speed, the motor 52 adjusts the speed of the first gear 67 by changing the switching meshing tooth surface, ensuring that the pause time of the first gear 67 during intermittent rotation is longer. This design can ensure the safety of the acid leaching operation and avoid the occurrence of bumping in the filter tank 4. Secondly, during the downward switching process, the key rod 63 is moved downward, which can change the angle of the extraction plate 74. In the first embodiment, since the extraction plate 74 is designed to be inclined, the contact surface of the extraction plate 74 can be maximized to contact the electrolytic aluminum slag, thereby ensuring sufficient secondary alkali mixing. During the acid leaching process, the extraction plate 74 can be switched to a horizontal direction. In this way, the contact area between the extraction plate 74 and the filter residue is minimized during the acid leaching process. This ensures that the rotational resistance is minimized and mixing and stirring can be achieved, ensuring that the filter residue is mixed and processed in a more stable state.

[0041] Third embodiment: See also Figure 5 、 Figure 7 and Figure 11 , further comprising a negative pressure mechanism 9; The negative pressure mechanism 9 includes a third gear 91 rotatably connected to the upper surface of the top cover 16, the top keyway of the third gear 91 is connected to a first pulley 92, the upper surface of the top cover 16 and located on one side of the third gear 91 is rotatably connected to a rotating rod 95, the top keyway of the rotating rod 95 is connected to a second pulley 93, the outer walls of the first pulley 92 and the second pulley 93 are provided with a belt 94, the bottom end of the rotating rod 95 and the keyway located inside the filter tank 4 are connected to a fan blade 96, the outer wall of the filter tank 4 and located above the fan blade 96 is fixed with an exhaust pipe 12, and one side of the third gear 91 is meshed and connected to the second gear 68.

[0042] The second half gear 57 and the second gear 68 are adapted to each other, the hollow tube 66 passes through the axis of the second gear 68 and does not contact the second gear 68 , and the second gear 68 is rotatably connected to the upper surface of the top cover 16 .

[0043] See also Figure 5 and Figure 11 During operation of the second embodiment, when the second half gear 57 is engaged with the second gear 68 , the motor 52 is started to control the first half gear 56 to engage with the first gear 67 and rotate, and to control the second half gear 57 to engage with the second gear 68 . When the second gear 68 rotates, the third gear 91 can be controlled to rotate. The third gear 91 controls the first pulley 92 to rotate. The transmission control belt 94 controls the second pulley 93 to rotate. During the rotation of the second pulley 93, the transmission control rod 95 can drive the fan blades 96 to rotate.

[0044] Understandable: Combined Figure 7 It can be seen that the hollow tube 66 is not connected to the second gear 68, so the rotation of the hollow tube 66 does not affect the operation of the second gear 68. Secondly, the axis of the second gear 68 adopts a hollow design and can be rotatably connected to the upper surface of the top cover 16 through a bearing. This embodiment

[0045] When the second embodiment is in operation, when the user switches the speed of the first gear 67, the second half gear 57 will mesh with the second gear 68, so that during the pickling process, the second half gear 57 will mesh with and control the rotation of the second gear 68; The second gear 68 drives the fan blade 96 to rotate in the filter tank 4. During the rotation of the fan blade 96, a slight negative pressure is formed in the internal space. At this time, the hydrofluoric acid gas generated during the acid leaching process will move upward and enter the slightly negative pressure environment, which can assist the exhaust pipe 12 to quickly discharge the hydrofluoric acid gas. The discharged hydrofluoric acid gas can assist in the preparation of cryolite.

[0046] Fourth embodiment: The lithium extraction and cryolite production process includes the following steps: S1: electrolytic aluminum slag, water and caustic soda are reacted in a certain mass ratio at a certain temperature for a period of time, and then filtered to obtain a mixed washing liquid of sodium metaaluminate and sodium hydroxide and a filter residue; Specifically: Electrolytic aluminum slag, water and caustic soda are reacted in a mass ratio of 1:0.5-5:0.1-5 at a temperature of 25-95 degrees for 0.2-5 hours and filtered to obtain a sodium metaaluminate / sodium hydroxide mixed washing solution; S2: acid leaching is performed on the filter residue, water and concentrated sulfuric acid in a certain ratio. After a period of reaction at a certain temperature, a slurry containing a lithium solution is obtained and hydrofluoric acid gas is generated; Specifically: The filter residue, water and concentrated sulfuric acid are acid-leached in a ratio of 1:0.5~5:0.1~5 at a temperature of 25~95 degrees. After reacting for 0.2~9 hours, a slurry of lithium solution is obtained and hydrofluoric acid gas is generated. S1 and S2 need to complete the operation in the filter tank 4 during the working process.

[0047] S3: subjecting the lithium solution-containing slurry to liquid-solid separation to obtain a lithium solution and crude cryolite; S4: adjusting the pH value of the lithium solution to 11-13 and then performing liquid-solid separation to obtain a lithium purified solution; S5: removing calcium ions and magnesium ions from the lithium purified solution using sodium carbonate and ion exchange resin to obtain a lithium purified solution; S6: The sodium aluminate / sodium hydroxide mixed washing solution in S1, the hydrofluoric acid gas in S2 and the crude cryolite produced in step S3 are mixed, and stirred at a certain temperature for 10 to 60 minutes to produce finished cryolite.

[0048] In summary, the present application obtains lithium brine by alkali washing, acid leaching and impurity removal of electrolytic aluminum slag. The lithium sulfate brine can be used as raw materials for producing lithium carbonate, lithium hydroxide and lithium chloride through traditional processes. At the same time, lithium is extracted from lithium-containing electrolytic aluminum slag and cryolite is co-produced. While effectively extracting lithium from the electrolytic aluminum slag, cryolite by-product can be obtained, thereby achieving maximum comprehensive utilization and improving the utilization rate of lithium.

[0049] 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 by using the contents of the present invention description and drawings under the concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A device for extracting lithium from electrolytic aluminum slag, characterized in that: It includes a bottom plate, a heating tank, an extraction tank, a filter tank, a top cover, a driving mechanism, a switching mechanism and a mixing mechanism; The heating tank is installed on the upper surface of the bottom plate, the extraction tank is installed inside the heating tank, the filter tank is installed inside the extraction tank, and the top cover is sealed and installed on the upper surface of the filter tank. The top cover is respectively installed with a liquid inlet pipe and a feed pipe; The driving mechanism includes a mounting base, a motor and a driving rod, wherein the mounting base is mounted on the upper surface of the top cover by bolts, the motor is mounted on the upper surface of the mounting base, the driving rod keyway is connected to the bottom output shaft of the motor, the outer wall of the driving rod is provided with a sliding sleeve, the outer wall of the sliding sleeve is threadedly connected with a positioning bolt, the bottom of the sliding sleeve is fixed with a first half gear, and the bottom of the first half gear is fixed with a second half gear; The upper and lower ends of the driving rod are rotatably connected to the mounting seat and the top cover; The switching mechanism includes a positioning seat, a first gear and a hollow tube. The positioning seat is mounted on the upper surface of the top cover and is located on one side of the mounting seat by bolts. The hollow tube is rotatably mounted on the axis of the top cover. The outer wall of the hollow tube and the internal keyway of the positioning seat are connected to the first gear. The mixing mechanism includes a mixing cylinder, a fixed plate and a mixing plate. The mixing cylinder is fixed to the inner wall of the filter tank, the fixed plate is fixed to the inner wall of the mixing cylinder, and the mixing plate is rotatably connected to the middle position of the fixed plate. The outer wall of the hollow tube and the internal keyway of the mixing cylinder are connected to the second bevel gear, the outer wall of the second bevel gear is meshed with the first bevel gear, and the outer wall of the hollow tube and the mixing rod are fixed below the second bevel gear.

2. The device for extracting lithium from electrolytic aluminum slag according to claim 1, characterized in that: The positioning bolt extends to the outer wall of the driving rod, the first half gear and the second half gear are slidably connected to the driving rod, and the first half gear and the second half gear are adapted to each other.

3. The device for extracting lithium from electrolytic aluminum slag according to claim 1, characterized in that: The outlet end of the liquid inlet pipe is directly above the mixing plate. One side of the mixing plate is rotatably connected to the inner wall of the mixing barrel through a bearing. The cross section of the mixing barrel is conical. The axis of the first bevel gear is connected to the keyway of the mixing plate.

4. The device for extracting lithium from electrolytic aluminum slag according to claim 1, characterized in that: It also includes extraction agencies; A first rotating ring is slidably connected to the outer wall of the driving rod and located above the sliding sleeve. A lifting plate is rotatably connected to the outer wall of the first rotating ring. A connecting rod is fixed to the top of the sliding sleeve. The interior of the positioning seat is rotatably connected to a third rotating ring, the internal keyway of the third rotating ring is connected to a key rod, the top end of the key rod is fixed with a top plate, the outer wall of the key rod is sleeved with a spring, and one side of the lifting plate and located above the top plate is rotatably connected to a second rotating ring; The extraction mechanism includes a sealing box fixedly mounted at the bottom end of the hollow tube, the interior of the sealing box is rotatably connected to two rotating shafts, the exteriors of the two rotating shafts are both mounted with extraction plates by bolts, the interior of the sealing box and at the axis centers of the two rotating shafts are both mounted with linkage plates, the interiors of the two linkage plates are both provided with notches, and the interior of the sealing box and at the bottom end of the key rod are fixed with a switching lever; A screw conveyor is installed at the bottom of the filter tank, a discharge pipe is installed at the bottom of the extraction tank, and an auxiliary rod is fixed at the bottom of the sealing box.

5. The device for extracting lithium from electrolytic aluminum slag according to claim 4, characterized in that: The top end of the connecting rod is fixedly connected to the upper surface of the first rotating ring, and the axis of the second rotating ring is connected to the axis key groove of the top plate.

6. The device for extracting lithium from electrolytic aluminum slag according to claim 4, characterized in that: The upper and lower ends of the spring are fixedly connected to the top plate and the third rotating ring, and the key rod is slidably connected to the hollow tube.

7. The device for extracting lithium from electrolytic aluminum slag according to claim 4, characterized in that: Also includes a negative pressure mechanism; The negative pressure mechanism includes a third gear rotatably connected to the upper surface of the top cover, the top keyway of the third gear is connected to the first pulley, the upper surface of the top cover and located on one side of the third gear is rotatably connected to a rotating rod, the top keyway of the rotating rod is connected to the second pulley, the outer walls of the first pulley and the second pulley are sleeved with belts, the bottom end of the rotating rod and the keyway located inside the filter tank are connected to fan blades, the outer wall of the filter tank and located above the fan blades are fixed with an exhaust pipe, and one side of the third gear is meshed and connected to the second gear.

8. The device for extracting lithium from electrolytic aluminum slag according to claim 7, characterized in that: The second half gear and the second gear are adapted to each other, the hollow tube passes through the axis of the second gear and does not contact the second gear, and the second gear is rotatably connected to the upper surface of the top cover.

9. A process for extracting lithium and producing cryolite, characterized in that: The lithium extraction and cryolite co-production process includes the lithium extraction device from electrolytic aluminum slag according to any one of claims 1 to 8, comprising the following steps: S1: electrolytic aluminum slag, water and caustic soda are reacted in a certain mass ratio at a certain temperature for a period of time, and then filtered to obtain a mixed washing liquid of sodium metaaluminate and sodium hydroxide and a filter residue; Specifically: Electrolytic aluminum slag, water and caustic soda are reacted in a mass ratio of 1:0.5-5:0.1-5 at a temperature of 25-95 degrees for 0.2-5 hours and filtered to obtain a sodium metaaluminate / sodium hydroxide mixed washing solution; S2: acid leaching is performed on the filter residue, water and concentrated sulfuric acid in a certain ratio. After a period of reaction at a certain temperature, a slurry containing a lithium solution is obtained and hydrofluoric acid gas is generated; Specifically: The filter residue, water and concentrated sulfuric acid are acid-leached in a ratio of 1:0.5~5:0.1~5 at a temperature of 25~95 degrees. After reacting for 0.2~9 hours, a lithium solution slurry is obtained and hydrofluoric acid gas is generated. S1 and S2 need to complete the operation in the filter tank during the working process; S3: subjecting the lithium solution-containing slurry to liquid-solid separation to obtain a lithium solution and crude cryolite; S4: adjusting the pH value of the lithium solution to 11-13 and then performing liquid-solid separation to obtain a lithium purified solution; S5: removing calcium ions and magnesium ions from the lithium purified solution using sodium carbonate and ion exchange resin to obtain a lithium purified solution; S6: The sodium aluminate / sodium hydroxide mixed washing solution in S1, the hydrofluoric acid gas in S2 and the crude cryolite produced in step S3 are mixed, and stirred at a certain temperature for 10 to 60 minutes to produce finished cryolite.

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