Equipment and process for recycling battery-grade lithium carbonate by roasting waste residues of aluminum electrolysis cell with assistance of aluminum salt

Abstract

The invention provides equipment and a process for recycling battery-grade lithium carbonate by roasting waste residues of an aluminum electrolysis cell with assistance of aluminum salt, and relates to the technical field of lithium carbonate preparation, the equipment comprises a reaction kettle body, a stirring mechanism, a driving mechanism and a medicament adding mechanism; the stirring mechanism comprises a stirring shaft which is vertically and rotatably connected to the interior of the reaction kettle body, and the stirring mechanism is used for mixing the sodium carbonate precipitant and the filtrate. According to the scheme, a stirring shaft finally drives a driving disc and a shifting plate to rotate anticlockwise, a rotating disc and a convex disc are driven to intermittently rotate clockwise under the cooperation of a driving block and a driven block, and the convex disc intermittently rotates to press a piston rod and a piston downwards through a contact piece, so that a sodium carbonate solution is conveyed to a water dropper through a liquid outlet hose; through intermittent rotation of the convex disc, the sodium carbonate solution is intermittently and slowly dropwise added into the filtrate, the lithium precipitation reaction concentration is accurately controlled, and the phenomenon that the added sodium carbonate solution has instantaneous extremely-high local supersaturation degree in the reaction kettle is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lithium carbonate preparation, and particularly relates to an equipment and process for recovering battery-grade lithium carbonate from aluminum electrolytic cell waste residue through aluminum salt assisted roasting. BACKGROUND

[0002] A large amount of fluoride-containing electrolyte waste residue is generated during the operation of an aluminum electrolytic cell, and the main components are cryolite, fluorinated and a small amount of lithium salt, etc. When the waste residue is exposed to the open air, rainwater leaching and percolate seepage into the ground will pollute groundwater and surrounding soil. Through resource treatment of the aluminum electrolytic cell waste residue, lithium carbonate used for preparing lithium battery positive electrode material can be recovered from the waste residue, and the low-value waste residue can be converted into high-value strategic resources.

[0003] In the related art, through resource treatment of the aluminum electrolytic cell waste residue, lithium carbonate used for preparing lithium battery positive electrode material can be recovered from the waste residue. However, in use, the existing part of the aluminum electrolytic cell waste residue recovery equipment is not convenient for slow dropwise addition of sodium carbonate solution, and the added sodium carbonate can create extremely high local supersaturation in the reaction kettle in an instant, resulting in the generation of small volume crystal particles, which is not convenient for subsequent washing of impurity ions adsorbed on the surface of the crystal, and also causes impurity co-precipitation, resulting in that the final product cannot meet the battery-grade standard.

[0004] Therefore, it is necessary to provide an equipment and process for recovering battery-grade lithium carbonate from aluminum electrolytic cell waste residue through aluminum salt assisted roasting to solve the above technical problems. SUMMARY

[0005] The present application provides an equipment and process for recovering battery-grade lithium carbonate from aluminum electrolytic cell waste residue through aluminum salt assisted roasting, which solves the problem that the existing part of the aluminum electrolytic cell waste residue recovery equipment is not convenient for slow dropwise addition of sodium carbonate solution in use.

[0006] To solve the above technical problems, the equipment for recovering battery-grade lithium carbonate from aluminum electrolytic cell waste residue through aluminum salt assisted roasting provided by the present application comprises a reaction kettle body, a stirring mechanism, a driving mechanism and a medicament adding mechanism;

[0007] The stirring mechanism comprises a stirring shaft vertically rotatably connected to the inside of the reaction kettle body, and the stirring mechanism is used for mixing sodium carbonate precipitant and filtrate;

[0008] The driving mechanism comprises a driving disc fixedly arranged on the surface of the stirring shaft, a dial plate fixedly arranged on the top of the driving disc, a partition plate fixedly arranged on the inner wall of the reaction kettle body, a rotating shaft rotatably connected to the left side of the top of the partition plate, a rotating disc fixedly arranged on the top of the rotating shaft, a plurality of passive blocks annularly arranged on the outer edge of the top of the rotating disc, and a plurality of active blocks annularly arranged on the protruding position of the middle of the rotating disc;

[0009] The medicine adding mechanism comprises a medicine cylinder fixed on the top of the partition plate, a piston and a piston rod are slidably connected in the medicine cylinder, a spring is sleeved on the side surface of the piston rod and located at the top of the medicine cylinder, a contact piece is fixed on the top end of the piston rod, a convex disc is fixed on the bottom of the rotating disc, the top of the contact piece is in contact with the convex disc, a liquid outlet hose is communicated with the bottom of the medicine cylinder, and a plurality of drip heads are communicated with the medicine cylinder through the liquid outlet hose.

[0010] Preferably, a through groove is arranged on the surface of the driving disc and used in cooperation with the passive block, the height of the active block is higher than that of the passive block, and when the driving disc drives the dial to rotate counterclockwise, the dial is intermittently driven to rotate by the active block.

[0011] Preferably, a feeding mechanism is fixed on the top of the partition plate, the feeding mechanism comprises two mounting brackets fixed on the top of the partition plate, two guide wheels are rotatably connected to the top of the two mounting brackets respectively, the four guide wheels are divided into two groups, reciprocating plates are slidably connected to the opposite sides of the two groups of guide wheels, a tension spring is fixed on the side of the mounting bracket opposite to the reciprocating plate, a trigger bracket is fixed on the top of the reciprocating plate, a feeding pipe is vertically fixed in the reaction kettle body, and a discharging pipe is vertically fixed in the partition plate.

[0012] Preferably, when the active block rotates, the reciprocating plate is pushed to the right by the trigger bracket, a through hole is arranged in the reciprocating plate, and when the reciprocating plate moves to the rightmost position, the feeding pipe and the discharging pipe are in communication state under the action of the through hole.

[0013] Preferably, a dispersion mechanism is rotatably connected to the inside of the partition plate, the dispersion mechanism comprises a rotating shaft rotatably connected to the inside of the partition plate, a dispersion disc is fixed on the bottom end of the rotating shaft, a gear is fixed on the top end of the rotating shaft, and a gear tooth group is fixed on the right side of the front surface of the reciprocating plate and engaged with the gear.

[0014] Preferably, the stirring shaft is rotatably connected to the partition plate, stirring paddles are fixed on the side surface of the stirring shaft and located in the inside of the reaction kettle body, and a driving motor is arranged on the top of the reaction kettle body and used for driving the stirring shaft to rotate.

[0015] Preferably, a wall scraping mechanism is arranged in the reaction kettle body, the wall scraping mechanism comprises a scraper arranged in the reaction kettle body, a threaded screw rod is rotatably connected to the inside of the partition plate, the threaded screw rod is threadedly connected with the scraper, a guide rod is slidably connected to the inside of the scraper, the top end of the guide rod is fixedly connected with the bottom of the partition plate, a belt pulley is fixed on the surface of the top end of the threaded screw rod and the stirring shaft, a belt is sleeved on the surfaces of the two belt pulleys, and the drip heads are arranged in the inside of the scraper in an annular array.

[0016] Preferably, the left side of the reaction kettle body is communicated with a liquid inlet pipe, the bottom of the reaction kettle body is communicated with a liquid outlet pipe, the top of the reaction kettle body is communicated with an exhaust pipe, and a plurality of supporting legs are fixedly arranged at the bottom of the reaction kettle body.

[0017] The process for recovering battery-grade lithium carbonate from aluminum electrolysis cell waste residue by aluminum salt assisted roasting comprises the following steps:

[0018] In step S1, the electrolyte of the aluminum electrolysis cell is crushed and ground by a ball mill, and then dried in an oven after sieving for standby use.

[0019] In step S2, the dried electrolyte and anhydrous aluminum sulfate are weighed according to a certain mass ratio, mixed and ground in a agate crucible, and then transferred to a corundum crucible and placed in a tube furnace for roasting, so that the cryolite and calcium fluoride are converted into soluble fluorides.

[0020] In step S3, the roasting cooling product is mixed with deionized water according to a certain solid-liquid ratio, and sulfuric acid is added to adjust the pH to 2.0-3.0, and then placed in a constant-temperature water bath for stirring and reaction for a period of time, and then filtered to obtain filter residue A and filtrate A, the filter residue A is washed with water for three times according to a certain solid-liquid ratio until the water washing liquid is neutral, and then dried, which can be used as building aggregate and cement admixture.

[0021] In step S4, the filtrate A and the water washing liquid are mixed, and sodium hydroxide is added to adjust the pH to 5.5-6.5, and then placed in a constant-temperature water bath for stirring and reaction, and then solid-liquid separation is performed to obtain white filter residue B with a composition of aluminum hydroxy fluoride and filtrate B, and the filter residue A is dried in an oven and then transferred to a corundum crucible and placed in a muffle furnace for calcination to obtain aluminum fluoride.

[0022] In step S5, sodium hydroxide is added to the filtrate B to adjust the pH to 11.5-12.5, and then placed in a constant-temperature water bath for reaction for a period of time, and then the composition is detected, and according to the detected concentration of calcium ions, sodium carbonate is added for continuous reaction to precipitate calcium and magnesium impurity ions in the solution, and then solid-liquid separation is performed to obtain filtrate C.

[0023] In step S6, the filtrate C is concentrated to increase the concentration of lithium ions in the solution, and then the composition is detected, and then placed in a reaction kettle body, and according to the coefficient, sodium carbonate is continuously added for reaction, and then solid-liquid separation is performed to obtain lithium carbonate and filtrate D.

[0024] In step S7, a small amount of concentrated sulfuric acid is added to the filtrate D for reaction and decarburization, and then evaporation crystallization is performed after the decarburization is completed, and then solid-liquid separation is performed to obtain mirabilite, and the mirabilite is dried in an oven to obtain sodium sulfate.

[0025] Compared with the related art, the equipment and process for recovering battery-grade lithium carbonate from aluminum electrolysis cell waste residue by aluminum salt assisted roasting provided by the present application has the following beneficial effects:

[0026] The stirring shaft drives the drive disc and the dial plate to rotate counterclockwise. With the cooperation of the active and passive blocks, the rotating disc and the cam disc rotate intermittently clockwise. The intermittent rotation of the cam disc then presses the piston rod and piston downward through the contact element, allowing the sodium carbonate solution to be delivered to the dropper through the outlet hose. Through the intermittent rotation of the cam disc, the sodium carbonate solution is intermittently and slowly added to the filtrate, precisely controlling the concentration of the lithium precipitation reaction. This avoids the instantaneous extremely high local supersaturation of the added sodium carbonate solution in the reactor, allowing the lithium carbonate crystals to crystallize slowly and preventing impurities from being trapped during crystallization. This improves the chemical purity of the product, reduces the difficulty of subsequent washing, and the dropping process requires no manual intervention, exhibiting high stability. Attached Figure Description

[0027] 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.

[0028] Figure 1 The optimal structural schematic diagram provided for this invention;

[0029] Figure 2 This is a schematic diagram of the cross-sectional view of the reaction vessel body provided by the present invention;

[0030] Figure 3 for Figure 2 The diagram shows the structure of the partition plate.

[0031] Figure 4 Schematic diagram of the drive mechanism and the agent addition mechanism provided by the present invention;

[0032] Figure 5 The diagram shows the state in which the stirring shaft provided by the present invention drives the drive disk and the paddle plate to rotate, and drives the rotating disk to rotate clockwise under the cooperation of the active block and the passive block.

[0033] Figure 6 for Figure 4 The diagram shows a structural schematic of the cross-sectional view of the cartridge case.

[0034] Figure 7 A schematic diagram showing the state in which the rotating disk drives the cam to rotate clockwise, causing the piston rod and piston to slide downwards, as provided by the present invention.

[0035] Figure 8 This is a schematic diagram of the dispensing mechanism provided by the present invention;

[0036] Figure 9The rotating disc drives the active block to rotate, and the reciprocating plate is driven to move to the right under the action of the trigger support.

[0037] Figure 10 The structure schematic view of the dispersing mechanism is provided.

[0038] Figure 11 The structure schematic view of the stirring mechanism is provided.

[0039] Figure 12 The structure schematic view of the wall scraping mechanism is provided.

[0040] Figure 13 The process flow schematic view is provided.

[0041] Explanation of reference numerals:

[0042] 1, reaction kettle body;

[0043] 2, stirring mechanism; 21, stirring shaft; 22, stirring paddle; 23, driving motor;

[0044] 3, driving mechanism; 31, driving disc; 32, push plate; 33, rotating shaft; 34, rotating disc; 35, passive block; 36, active block;

[0045] 4, medicament adding mechanism; 41, medicine cartridge; 42, piston; 43, piston rod; 44, spring; 45, contact piece; 46, convex disc; 47, dripper;

[0046] 5, partition plate;

[0047] 6, feeding mechanism; 61, mounting support; 62, guide wheel; 63, reciprocating plate; 64, tension spring; 65, trigger support; 66, feeding pipe; 67, discharging pipe;

[0048] 7, dispersing mechanism; 71, rotating shaft; 72, dispersing disc; 73, gear; 74, gear set;

[0049] 8, wall scraping mechanism; 81, scraper; 82, threaded screw; 83, guide rod; 84, pulley; 85, belt;

[0050] 9, liquid inlet pipe; 10, liquid outlet pipe; 11, exhaust pipe; 12, supporting leg. DETAILED DESCRIPTION

[0051] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0052] The application provides an equipment for recovering battery-grade lithium carbonate from aluminum electrolysis cell waste residue by aluminum salt assisted roasting.

[0053] First embodiment:

[0054] Please refer to Figures 1 to 7 and Figure 12 , the equipment for recovering battery-grade lithium carbonate from aluminum electrolysis cell waste residue by aluminum salt assisted roasting comprises a reaction kettle body 1, a stirring mechanism 2, a driving mechanism 3 and a medicament adding mechanism 4.

[0055] The stirring mechanism 2 comprises a stirring shaft 21 vertically connected to the inside of the reaction kettle body 1, and the stirring mechanism 2 is used for mixing the sodium carbonate precipitant and the filtrate.

[0056] The driving mechanism 3 comprises a driving disc 31 fixedly arranged on the surface of the stirring shaft 21, a dial plate 32 fixedly arranged on the top of the driving disc 31, a partition plate 5 fixedly arranged on the inner wall of the reaction kettle body 1, a rotating shaft 33 rotatably connected to the left side of the top of the partition plate 5, a rotating disc 34 fixedly arranged on the top of the rotating shaft 33, a plurality of passive blocks 35 arranged in an annular array on the outer edge of the top of the rotating disc 34, and a plurality of active blocks 36 arranged in an annular array on the protruding position of the middle of the rotating disc 34.

[0057] The medicament adding mechanism 4 comprises a medicine cartridge 41 fixedly arranged on the top of the partition plate 5, a piston 42 and a piston rod 43 slidably connected to the inside of the medicine cartridge 41, a spring 44 sleeved on the top of the piston rod 43, a contact piece 45 fixedly arranged on the top end of the piston rod 43, a convex disc 46 fixedly arranged on the bottom of the rotating disc 34, the convex disc 46 in contact with the top of the contact piece 45, a liquid outlet hose communicated with the bottom of the medicine cartridge 41, and a plurality of drips 47 communicated with the medicine cartridge 41 through the liquid outlet hose.

[0058] The surface of the driving disc 31 is provided with a through groove matched with the passive blocks 35, the height of the active blocks 36 is higher than that of the passive blocks 35, and when the driving disc 31 drives the dial plate 32 to rotate counterclockwise, the dial plate 32 will push the rotating disc 34 to rotate intermittently through the active blocks 36.

[0059] Preferably, the left side of the medicine cartridge 41 is communicated with a liquid inlet hose, and the surface of the liquid inlet hose and the liquid outlet hose is provided with a one-way valve, and the reaction kettle body 1 has a heating function.

[0060] Please combine Figure 4 and Figure 5 : When the stirring shaft 21 rotates counterclockwise, the driving disc 31 and the push plate 32 will rotate counterclockwise at the same time. When the push plate 32 rotates counterclockwise and contacts the driving block 36, the driving block 36 will push the rotating disc 34 to rotate intermittently once. During the intermittent rotation of the rotating disc 34, the passive block 35 will rotate at the same time, so that the passive block 35 rotates to the through slot of the driving disc 31. Under the continuous rotation of the driving disc 31, the rotating disc 34 will be driven by the passive block 35 to rotate intermittently once (slightly paused between the time of the last intermittent rotation). Under the intermittent rotation of the rotating disc 34, the next driving block 36 will be rotated to the position where the push plate 32 is in contact (i.e. the position where the push plate 32 rotates counterclockwise and contacts the driving block 36). In this way, through the counterclockwise rotation of the driving disc 31 and the push plate 32, the driving disc 31 is driven to rotate clockwise intermittently under the cooperation of the driving block 36 and the passive block 35;

[0061] Please combine Figure 6 and Figure 7 : When the driving disc 31 rotates clockwise intermittently, the convex disc 46 at the bottom will rotate at the same time. Through the rotation of the convex disc 46, the piston rod 43 is pressed downward by the contact piece 45. The piston rod 43 moves downward, thereby driving the piston 42 to slide downward in the inside of the cartridge 41. The sodium carbonate solution is transported to the drop head 47 through the liquid outlet hose. The sodium carbonate solution is added to the filtrate by the drop head 47. Through the intermittent rotation of the driving disc 31 driving the convex disc 46, the sodium carbonate solution is added to the filtrate intermittently and slowly.

[0062] Further, when the convex disc 46 is in contact with the contact piece 45 at the most convex position and continues to rotate intermittently clockwise, the piston rod 43 and the piston 42 slide upward by the action of the spring 44, so that the top of the contact piece 45 is always in contact with the bottom of the convex disc 46. Through the upward sliding of the piston rod 43 and the piston 42, the sodium carbonate solution is extracted by the liquid inlet hose.

[0063] In this embodiment, the driving disc 31 and the push plate 32 are driven to rotate counterclockwise by the stirring shaft 21, and the rotating disc 34 and the convex disc 46 are driven to rotate clockwise intermittently by the cooperation of the driving block 36 and the driven block 35. The intermittent rotation of the convex disc 46 further drives the piston rod 43 and the piston 42 to move downward through the contact piece 45, so that the sodium carbonate solution is transported to the drop head 47 through the liquid outlet hose. The sodium carbonate solution is added to the filtrate intermittently and slowly through the intermittent rotation of the convex disc 46, so as to accurately control the lithium precipitation reaction concentration and avoid the addition of sodium carbonate solution in the reaction kettle. The lithium carbonate crystal is slowly crystallized, the impurities are avoided to be wrapped in the crystal during the crystallization process, so as to improve the chemical purity of the product and reduce the difficulty of subsequent washing. At the same time, the drop adding process does not need manual intervention, and has high stability.

[0064] Second embodiment:

[0065] Please refer to Figures 8 to 10 , the top of the partition plate 5 is fixed with a feeding mechanism 6, the feeding mechanism 6 includes two mounting brackets 61 fixed on the top of the partition plate 5, the top of the two mounting brackets 61 is rotatably connected with two guide wheels 62, the four guide wheels 62 are divided into front and rear two groups, the opposite side of the two groups of guide wheels 62 is slidably connected with a reciprocating plate 63, the opposite side of the reciprocating plate 63 and the left mounting bracket 61 is fixedly connected with a tension spring 64, the top of the reciprocating plate 63 is fixedly connected with a trigger bracket 65, the inside of the reaction kettle body 1 is vertically fixedly connected with a feeding pipe 66, and the inside of the partition plate 5 is vertically fixedly connected with a discharging pipe 67.

[0066] When the driving block 36 rotates, the reciprocating plate 63 is pushed to the right through the trigger bracket 65, and a through hole is formed in the inside of the reciprocating plate 63. When the reciprocating plate 63 moves to the rightmost side of the stroke, the feeding pipe 66 and the discharging pipe 67 form a communication state under the action of the through hole.

[0067] The inside of the partition plate 5 is vertically rotatably connected with a dispersing mechanism 7, the dispersing mechanism 7 includes a rotating shaft 71 rotatably connected to the inside of the partition plate 5, the bottom end of the rotating shaft 71 is fixedly connected with a dispersing disc 72, the top end of the rotating shaft 71 is fixedly connected with a gear 73, the right side of the front of the reciprocating plate 63 is fixedly connected with a gear set 74, and the gear set 74 is engaged with the gear 73.

[0068] Please refer to Figure 8 and Figure 9 : when the rotating disc 34 drives the driving block 36 to rotate clockwise, the driving block 36 pushes the reciprocating plate 63 to the right through the trigger bracket 65, so that the tension spring 64 is stretched. When the reciprocating plate 63 moves to the rightmost side of the stroke, the feeding pipe 66 and the discharging pipe 67 will form a communication state under the action of the through hole, so that the lithium carbonate crystal powder falls into the reaction kettle body 1;

[0069] Further, when the reciprocating plate 63 moves to the rightmost side of the stroke, the driving block 36 continues to be driven by the rotating disc 34 to rotate clockwise, so that the current driving block 36 is separated from the trigger support 65, and under the action of the tension spring 64, the reciprocating plate 63 quickly drives the trigger support 65 to reset, thereby stopping the release of lithium carbonate crystal powder, and the driving block 36 is intermittently driven by the rotating disc 34 to rotate clockwise, thereby intermittently adding lithium carbonate crystal powder into the reaction kettle body 1.

[0070] Please refer to Figure 10 : When the reciprocating plate 63 moves to the right, the gear set 74 will also move to the right, and the gear set 74 will drive the rotating shaft 71 and the dispersion disc 72 to rotate clockwise through the gear 73. When the lithium carbonate crystal powder falls on the top of the dispersion disc 72 and the reciprocating plate 63 quickly resets to the left, the reciprocating plate 63 will also quickly move to the left, thereby driving the gear 73 to rotate the dispersion disc 72 counterclockwise through the rotating shaft 71, and the lithium carbonate crystal powder on the top of the dispersion disc 72 is scattered into the reaction solution, and the lithium carbonate crystal growth is guided by the addition of lithium carbonate crystal powder.

[0071] In this embodiment, the driving block 36 is intermittently rotated by the rotating disc 34, which drives the reciprocating plate 63 to move to the right through the trigger support 65. When the reciprocating plate 63 moves to the rightmost side of the stroke, the feeding pipe 66 and the discharge pipe 67 are in communication under the action of the through hole, so that the lithium carbonate crystal powder falls on the top of the dispersion disc 72. When the trigger support 65 is separated from the current driving block 36, the reciprocating plate 63 will quickly drive the gear set 74 to move to the left under the action of the tension spring 64, thereby driving the gear 73 to rotate the dispersion disc 72 counterclockwise through the rotating shaft 71, and the lithium carbonate crystal on the top is dispersed into the solution, and the lithium carbonate crystal growth is guided by the addition of lithium carbonate crystal powder, which avoids the impurities wrapping caused by irregular crystallization. At the same time, by intermittently releasing the lithium carbonate crystal powder and instantaneously dispersing, it can ensure that the seed can uniformly cover the entire reaction liquid surface, and facilitate the formation of products with uniform particle size.

[0072] Third embodiment:

[0073] Please refer to Figure 1 、 Figure 11 and Figure 12 , the stirring shaft 21 is vertically connected with the partition plate 5, and the stirring paddle 22 is fixed on the side surface of the stirring shaft 21 and located inside the reaction kettle body 1, and the top of the reaction kettle body 1 is provided with a driving motor 23 for driving the stirring shaft 21 to rotate.

[0074] The inside of the reaction kettle body 1 is provided with a wall scraping mechanism 8, the wall scraping mechanism 8 comprises a scraper 81 arranged in the inside of the reaction kettle body 1, a threaded screw rod 82 is vertically connected in the inside of the partition plate 5, the threaded screw rod 82 is threadedly connected with the scraper 81, a guide rod 83 is vertically and slidingly connected in the inside of the scraper 81, the top end of the guide rod 83 is fixedly connected with the bottom of the partition plate 5, the top end of the threaded screw rod 82 and the surface of the stirring shaft 21 are both fixedly provided with a belt pulley 84, the surfaces of the two belt pulleys 84 are sleeved with a belt 85, and the drop heads 47 are arranged in the inside of the scraper 81 in an annular array.

[0075] The left side of the reaction kettle body 1 is communicated with a liquid inlet pipe 9, the bottom of the reaction kettle body 1 is communicated with a liquid outlet pipe 10, the top of the reaction kettle body 1 is communicated with an exhaust pipe 11, and a plurality of supporting legs 12 are fixedly arranged at the bottom of the reaction kettle body 1.

[0076] Please combine Figure 11 : the driving motor 23 is started, the driving motor 23 rotates to drive the stirring shaft 21 and the stirring paddle 22 to rotate, and the filtrate and the sodium carbonate solution are mixed through the rotation of the stirring paddle 22.

[0077] Please combine Figure 12 : when the stirring shaft 21 rotates, the threaded screw rod 82 is simultaneously driven to rotate through the belt pulley 84 and the belt 85, the threaded screw rod 82 rotates to drive the scraper 81 to move downwards, the inside of the reaction kettle body 1 is cleaned by the scraper 81, the scraper 81 moves up and down through the forward and reverse rotation of the stirring shaft 21, and the drop heads 47 move downwards simultaneously when the scraper 81 moves up and down, so that the working position of the drop heads 47 is adjusted.

[0078] Preferably, before the reaction kettle works, the working position of the drop heads 47 is first adjusted through the rotation of the stirring shaft 21, the drop heads 47 are located below the liquid level, after the adjustment, the belt 85 is disassembled, the scraper 81 is prevented from disturbing the fluid and interfering with the crystallization of lithium carbonate when the stirring shaft 21 is used for stirring and mixing the filtrate and the sodium carbonate solution, and the exhaust pipe 11 is externally connected with a gas treatment equipment.

[0079] In the embodiment, the stirring paddle 22 is driven to rotate by the stirring shaft 21, the filtrate and the sodium carbonate solution are mixed, when the inside of the reaction kettle body 1 needs to be cleaned, the scraper 81 moves up and down through the rotation of the threaded screw rod 82 under the cooperation of the belt pulley 84 and the belt 85, the inside of the reaction kettle body 1 is cleaned, the lithium carbonate crystals are prevented from adhering to the inner wall of the reaction kettle and forming scabs, and the working position of the drop heads 47 can also be adjusted through the movement of the scraper 81.

[0080] The application also provides a process for recovering battery-grade lithium carbonate from aluminum electrolysis cell waste residue by aluminum salt assisted roasting.

[0081] Please refer toFigure 13 The process for recovering battery-grade lithium carbonate from aluminum salt-assisted roasting aluminum electrolytic cell waste includes the following steps:

[0082] Step S1: Crush the electrolyte in the aluminum electrolysis cell, grind it through a ball mill, sieve it, and place it in an oven to dry for later use;

[0083] Step S2: Weigh the dried electrolyte and anhydrous aluminum sulfate, grind and mix them in an agate crucible according to a certain mass ratio, transfer the mixture to a corundum crucible, and place it in a tube furnace for calcination, so that cryolite and calcium fluoride are converted into soluble fluorides.

[0084] Step S3: Mix the calcined cooling material with deionized water in a certain solid-liquid ratio, and add sulfuric acid to adjust the pH of the solution to 2.0-3.0. Place the mixture in a constant temperature water bath and stir for a period of time. After the reaction is completed, filter to obtain filter residue A and filtrate A. Filter residue A is washed three times with water in a certain solid-liquid ratio until the washing liquid is neutral. After drying, the filter residue can be used as building aggregate and cement admixture.

[0085] Step S4: Mix filtrate A and washing solution, add sodium hydroxide to adjust pH to 5.5-6.5, place in a constant temperature water bath and stir to react. After the reaction is completed, separate the solid and liquid to obtain white filter residue B and filtrate B with aluminum hydroxy fluoride. After drying filter residue A in an oven, transfer it to a corundum crucible and calcine it in a muffle furnace to obtain aluminum fluoride.

[0086] Step S5: Add sodium hydroxide to filtrate B to adjust the pH to 11.5-12.5, place it in a constant temperature water bath for a period of time and send it for component testing. Add sodium carbonate according to the detected calcium ion concentration to continue the reaction, promote the precipitation of impurity ions such as calcium and magnesium in the solution, and obtain filtrate C by solid-liquid separation.

[0087] Step S6: Concentrate filtrate C to increase the lithium ion concentration in the solution and send it for component analysis. Then place it in reaction vessel 1 and continue to add sodium carbonate according to the coefficient to carry out the reaction. After the reaction is completed, solid-liquid separation is performed to obtain lithium carbonate and filtrate D.

[0088] Step S7: Add a small amount of concentrated sulfuric acid to the filtrate D to react and decarbonize. After decarbonization, evaporate and crystallize, and separate the solid and liquid to obtain sodium sulfate. Place the sodium sulfate in an oven to dry and obtain sodium sulfate.

[0089] In this process, insoluble fluorides in the electrolytic waste residue of aluminum electrolysis cells are converted into soluble fluorides through a roasting-leaching process, achieving highly selective leaching of fluorine, sodium, aluminum, and lithium, and recovering aluminum fluoride, lithium carbonate, and sodium sulfate products. The recovered lithium carbonate is used as a raw material for lithium battery cathode materials, while the filter residue is used as a resource in the construction industry. This process breaks through the traditional recycling bottleneck and provides a new path for the high-value utilization of waste electrolytes in the aluminum industry, with significant economic and environmental benefits.

[0090] Please refer to Figures 1 to 12 The working principle of the equipment for recovering battery-grade lithium carbonate from aluminum electrolysis tank waste residue with the aid of aluminum salt roasting provided by the present application is as follows:

[0091] Step S1, the filtrate is delivered into the reaction kettle body 1, and then the driving motor 23 is started, the driving motor 23 rotates to drive the stirring shaft 21 and the stirring paddle 22 to rotate counterclockwise, and the stirring paddle 22 rotates to stir the filtrate;

[0092] Step S2, when the stirring shaft 21 rotates counterclockwise, the driving disc 31 and the push plate 32 will also rotate counterclockwise, when the push plate 32 rotates counterclockwise and contacts the driving block 36, the driving block 36 will push the rotating disc 34 to rotate intermittently once, and the rotating disc 34 will rotate the driven block 35 to rotate to the through slot of the driving disc 31, under the continuous rotation of the driving disc 31, the driven block 35 will drive the rotating disc 34 to rotate intermittently once (slightly paused after the time of the last intermittent rotation), and under the intermittent rotation of the rotating disc 34, the next driving block 36 will be rotated to the position where the push plate 32 is contacted (i.e. the position where the push plate 32 rotates counterclockwise and contacts the driving block 36), and thus the cycle is formed, under the counterclockwise rotation of the driving disc 31 and the push plate 32, the driving block 36 and the driven block 35 are cooperated to drive the driving disc 31 to rotate clockwise intermittently;

[0093] Step S3, when the driving disc 31 rotates clockwise intermittently, the convex disc 46 at the bottom will also rotate, through the rotation of the convex disc 46, the piston rod 43 is pressed downward by the contact piece 45, the piston rod 43 moves downward to drive the piston 42 to slide downward in the inside of the cartridge 41, the sodium carbonate solution is delivered to the drop head 47 through the liquid outlet hose, and the sodium carbonate solution is added to the filtrate by the drop head 47;

[0094] Step S4, when the rotating disc 34 drives the driving block 36 to rotate clockwise, the driving block 36 will push the reciprocating plate 63 to the right through the trigger bracket 65, so that the tension spring 64 is stretched, when the reciprocating plate 63 moves to the rightmost side of the stroke, the feeding pipe 66 and the discharging pipe 67 will be in a communication state under the action of the through hole, so that the lithium carbonate crystal powder falls into the top of the dispersion disc 72;

[0095] When the reciprocating plate 63 moves to the rightmost side of the stroke, the current driving block 36 is separated from the trigger bracket 65 by the continued clockwise rotation of the rotating disc 34, the reciprocating plate 63 quickly drives the trigger bracket 65 to reset under the action of the tension spring 64, so that the addition of the lithium carbonate crystal powder is stopped, and the lithium carbonate crystal powder is intermittently added into the reaction kettle body 1 by the intermittent clockwise rotation of the rotating disc 34.

[0096] When the reciprocating plate 63 moves to the right, the gear set 74 is simultaneously moved to the right, and the gear set 74 is further moved to the right to drive the rotating shaft 71 and the dispersion disc 72 to rotate clockwise through the gear 73. When the lithium carbonate crystal powder is dropped on the top of the dispersion disc 72, and the reciprocating plate 63 is quickly reset to the left, the reciprocating plate 63 simultaneously drives the gear set 74 to quickly move to the left, so that the gear 73 drives the dispersion disc 72 to rotate counterclockwise through the rotating shaft 71, and the lithium carbonate crystal powder on the top of the dispersion disc 72 is scattered into the reaction solution.

[0097] When the reciprocating plate 63 moves to the right, the gear set 74 is simultaneously moved to the right, and the gear set 74 is further moved to the right to drive the rotating shaft 71 and the dispersion disc 72 to rotate clockwise through the gear 73. When the lithium carbonate crystal powder is dropped on the top of the dispersion disc 72, and the reciprocating plate 63 is quickly reset to the left, the reciprocating plate 63 simultaneously drives the gear set 74 to quickly move to the left, so that the gear 73 drives the dispersion disc 72 to rotate counterclockwise through the rotating shaft 71, and the lithium carbonate crystal powder on the top of the dispersion disc 72 is scattered into the reaction solution.

[0098] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or the like within the concept of the present application, and the contents of the present application specification and drawings are included in the patent protection scope of the present application.

Claims

1. An apparatus for recovering battery grade lithium carbonate from aluminum electrolysis cell waste residue with the aid of aluminum salt roasting, characterized in that, Including the reaction kettle body, stirring mechanism, drive mechanism and medicament adding mechanism; The stirring mechanism includes a stirring shaft vertically connected to the inside of the reaction kettle body, and is used for mixing the sodium carbonate precipitant and the filtrate. The drive mechanism includes a drive disc fixed on the surface of the stirring shaft, and a dial plate fixed on the top of the drive disc. The medicament adding mechanism includes a cartridge fixed on the top of the partition plate, and a piston and a piston rod slidably connected in the cartridge.

2. The plant for recovering battery grade lithium carbonate from spent potliner of aluminum electrolysis cells with the aid of calcination of aluminum salts according to claim 1, characterized in that, The surface of the drive disc is provided with a through groove matched with the passive block.

3. The plant for recovering battery grade lithium carbonate from spent potliner of aluminum electrolysis cells with the aid of calcination of aluminum salts according to claim 1, characterized in that, The top of the partition plate is provided with a dropping mechanism including two mounting brackets fixed on the partition plate.

4. The plant for recovering battery grade lithium carbonate from spent potliner of aluminum electrolysis cells with the aid of aluminum salt roasting according to claim 3, characterized in that, The top of each mounting bracket is rotatably connected with a guide wheel.

5. The plant for recovering battery grade lithium carbonate from spent potliner of aluminum electrolysis cells with the aid of aluminum salt roasting according to claim 4, characterized in that, The four guide wheels are divided into two groups.

6. The plant for recovering battery grade lithium carbonate from spent potliner of aluminum electrolysis cells with the aid of calcination of aluminum salts according to claim 1, characterized in that, The opposite side of the two groups of guide wheels is slidably connected with a reciprocating plate. The opposite side of the mounting bracket is fixed with a tension spring. The top of the reciprocating plate is fixed with a trigger bracket. The inside of the reaction kettle body is vertically provided with a feeding pipe. The inside of the partition plate is vertically provided with a discharging pipe. The reciprocating plate is provided with a through hole. When the reciprocating plate moves to the rightmost side of the stroke, the feeding pipe and the discharging pipe are in communication state under the action of the through hole. The inside of the partition plate is rotatably connected with a dispersion mechanism. The dispersion mechanism includes a rotating shaft rotatably connected to the inside of the partition plate. The bottom end of the rotating shaft is fixed with a dispersion disc. The top end of the rotating shaft is fixed with a gear. The right side of the front of the reciprocating plate is fixed with a gear set. The gear set is engaged with the gear. The stirring shaft is rotatably connected with the partition plate. The surface of the stirring shaft is fixed with a stirring paddle in the inside of the reaction kettle body. The top of the reaction kettle body is provided with a drive motor for driving the stirring shaft to rotate.

7. The plant for recovering battery grade lithium carbonate from spent potliner of aluminum electrolysis cells with the aid of calcination of aluminum salts according to claim 1, characterized in that, The inside of the reaction kettle body is provided with a wall scraping mechanism, the wall scraping mechanism comprises a scraper arranged in the inside of the reaction kettle body, a threaded screw rod is vertically connected in the inside of the partition plate, the threaded screw rod is in threaded connection with the scraper, a guide rod is vertically and slidably connected in the inside of the scraper, the top end of the guide rod is fixedly connected with the bottom of the partition plate, the top end of the threaded screw rod and the surface of the stirring shaft are both fixedly provided with a belt pulley, the surfaces of the two belt pulleys are both provided with a belt, and the drip ring array is arranged in the inside of the scraper.

8. The plant for recovering battery grade lithium carbonate from spent potliner of aluminum electrolysis cells with the aid of calcination of aluminum salts according to claim 1, characterized in that, The left side of the reaction kettle body is communicated with a liquid inlet pipe, the bottom of the reaction kettle body is communicated with a liquid outlet pipe, the top of the reaction kettle body is communicated with an exhaust pipe, and a plurality of supporting legs are fixedly arranged on the bottom of the reaction kettle body.

9. A process for recovering battery grade lithium carbonate from spent potliner of aluminum reduction cells with the aid of aluminum salt roasting, characterized in that, The process for recycling battery-grade lithium carbonate comprises the equipment according to any one of claims 1-8 and the following steps: Step S1, crushing the electrolyte of the aluminum electrolysis cell, grinding through a ball mill, sieving, and drying in an oven for standby; Step S2, weighing the dried electrolyte and anhydrous aluminum sulfate, grinding and mixing in a agate crucible according to a certain mass ratio, transferring to a corundum crucible after uniform mixing, and roasting in a tube furnace to convert cryolite and calcium fluoride into soluble fluoride; Step S3, mixing the roasting cooling product with deionized water according to a certain solid-liquid ratio, adding sulfuric acid to adjust the pH of the solution to 2.0-3.0, stirring and reacting in a constant-temperature water bath for a period of time, filtering to obtain filter residue A and filtrate A after the reaction, washing the filter residue A with water for three times according to a certain solid-liquid ratio until the water washing liquid is neutral, and drying the filter residue A to be used as building aggregate and cement admixture; Step S4, mixing the filtrate A and the water washing liquid, adding sodium hydroxide to adjust the pH to 5.5-6.5, stirring and reacting in a constant-temperature water bath, and solid-liquid separation to obtain white filter residue B with aluminum hydroxy fluoride and filtrate B after the reaction, drying the filter residue A in an oven, transferring to a corundum crucible, and calcining in a muffle furnace to obtain aluminum fluoride; Step S5, adding sodium hydroxide to the filtrate B to adjust the pH to 11.5-12.5, reacting in a constant-temperature water bath for a period of time, adding sodium carbonate according to the detected concentration of calcium ions to continue the reaction, precipitating calcium and magnesium impurity ions in the solution, and solid-liquid separation to obtain filtrate C; Step S6, concentrating the filtrate C, detecting the composition after improving the concentration of lithium ions in the solution, then placing in a reaction kettle body, and continuously adding sodium carbonate according to the coefficient to react, solid-liquid separation to obtain lithium carbonate and filtrate D after the reaction; Step S7, adding a small amount of concentrated sulfuric acid to the filtrate D to react and remove carbon, evaporating and crystallizing after the carbon removal is completed, solid-liquid separation to obtain mirabilite, and drying the mirabilite in an oven to obtain sodium sulfate.

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