Lithium carbonate preparation reaction kettle and preparation method

Abstract

This invention discloses a lithium carbonate preparation reactor and preparation method, comprising an upper tank and a lower tank, which are fixedly connected. A filter assembly is provided at the connection between the upper and lower tanks. This invention relates to the field of lithium carbonate preparation reactor technology. In this lithium carbonate preparation reactor and preparation method, during feeding into the upper tank, a rotating clamp on the bottom side of the filter plate causes the filter plate and the filter holes inside the clamp to be misaligned, thus achieving a sealing effect. After the lithium carbonate precipitation mother liquor is stirred, the clamp is rotated to align with the filter holes inside the filter plate, allowing the lithium carbonate precipitation mother liquor to flow into the lower tank. Simultaneously, the filter screen in the filter plate filters the precipitate, preventing the precipitate from entering the lower tank and affecting the lithium carbonate preparation effect. Furthermore, the stirring blades on the inner wall of the inner cylinder rotate in the opposite direction to the upper stirring rod, ensuring thorough mixing of the lithium carbonate precipitation mother liquor and the precipitant in the upper tank, enhancing the precipitation effect of calcium and magnesium salts in the mother liquor, and thereby improving the purity of the prepared lithium carbonate.

Description

Technical Field

[0001] This invention relates to the field of lithium carbonate preparation reactor technology, specifically a lithium carbonate preparation reactor and preparation method. Background Technology

[0002] Lithium carbonate is used to produce various lithium compounds, metallic lithium, and its isotopes. It is also used to prepare catalysts for chemical reactions. Applications include semiconductors, ceramics, television, pharmaceuticals, and the nuclear energy industry. It is also used in lithium-ion batteries. In cement admixtures, it is used as a setting accelerator. There are many methods for preparing lithium carbonate, but high-purity lithium carbonate is typically prepared by recovering the mother liquor from battery-grade lithium carbonate precipitation. The process for preparing lithium carbonate from battery-grade lithium carbonate precipitation mother liquor includes stirring, filtration, heating, and cooling.

[0003] In the process of preparing lithium carbonate from battery-grade lithium carbonate mother liquor, a precipitant needs to be added to filter out internal calcium or magnesium salt precipitation. However, existing reaction vessels have many problems.

[0004] 1. After the lithium carbonate precipitation mother liquor is precipitated, it needs to be filtered. Due to the large scale of industrial production, multiple sets of reaction vessels are required for production, which occupies a lot of industrial equipment.

[0005] 2. Traditional stirring methods can only stir the internal solution in one direction, either clockwise or counterclockwise, resulting in low mixing efficiency of the liquid. This leads to low precipitation efficiency of calcium or magnesium salts, thereby reducing the purity of lithium carbonate preparation.

[0006] To address this issue, the present invention provides a lithium carbonate preparation reactor, in which the precipitated mother liquor is discharged into the lower tank through a filter assembly between the upper and lower tanks, while the stirring blades and stirring rods rotate in opposite directions to solve the aforementioned problems. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a lithium carbonate preparation reactor and preparation method, thus solving the aforementioned problems.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a lithium carbonate preparation reactor, comprising an upper tank and a lower tank, the upper tank and the lower tank being fixedly connected. A filter assembly is provided at the connection between the upper tank and the lower tank. The filter assembly includes a filter plate fixedly connected to the inner wall of the upper tank. A positioning ring is fixedly connected to the inner wall of the lower tank. A clamping plate is rotatably connected inside the positioning ring. Filter holes are provided inside both the filter plate and the clamping plate. The clamping plate is rotatably connected to the inside of the filter plate. A filter screen is fixedly connected to the filter holes of the filter plate. A shell is fixedly connected to one side of the lower tank. A rotating plate is rotatably connected inside the shell. The rotating plate is fixedly connected to the clamping plate.

[0009] Preferably, the filter plate and the card plate have a 40° angle between their internal filter holes, the filter screen has a pore size of 0.7-1.2 cm, and the filter plate and the card plate have trapezoidal cross-sections.

[0010] Preferably, the upper tank is symmetrically fixedly connected with retaining rings inside, and an inner cylinder is rotatably connected between the two retaining rings. The inner wall of the inner cylinder is symmetrically fixedly connected with stirring blades, and the stirring blades have through holes inside.

[0011] Preferably, the upper tank and the lower tank are rotatably connected by a rotating shaft, the outer end of the rotating shaft is movably connected to a sleeve rod, the sleeve rod is fixedly connected to the inner cylinder, the outer end of the rotating shaft is fixedly connected to an upper stirring rod, the upper stirring rod is located inside the inner cylinder, and the upper stirring rod is displaced from the stirring blade.

[0012] Preferably, an assembly box is fixedly connected to the top of the upper tank, a servo motor is fixedly connected to one side of the assembly box, the rotating shaft and the sleeve rod are both rotatably connected inside the assembly box, a first driven bevel gear is fixedly connected to the outer end of the rotating shaft, a second driven bevel gear is fixedly connected to the outer end of the sleeve rod, and a transmission bevel gear is fixedly connected to the output end of the servo motor. The transmission bevel gear is located between the first driven bevel gear and the second driven bevel gear and meshes with each other.

[0013] Preferably, a fixing ring is fixedly connected to the inner wall of the lower tank, the rotating shaft is rotatably connected to the fixing ring, a lower stirring rod is fixedly connected to the side of the rotating shaft away from the upper stirring rod, and a scraper is fixedly connected to the outer side of the bottom end of the rotating shaft, the bottom side of the scraper being arc-shaped.

[0014] Preferably, a pressure relief pipe is fixedly connected to the top of the upper tank, a pneumatic plug is slidably connected inside the pressure relief pipe, a push rod is fixedly connected to the top of the pneumatic plug, the push rod is slidably connected to the pressure relief pipe, a spring is fixedly connected between the push rod and the pressure relief pipe, and an air hole is opened on the side wall of the pressure relief pipe.

[0015] Preferably, a vent pipe is fixedly connected to the top end of the pressure relief pipe, a filter cartridge is fixedly connected to the other end of the vent pipe, an activated carbon layer is provided inside the filter cartridge, and an exhaust pipe is fixedly connected to the bottom end of the filter cartridge.

[0016] Preferably, a hollow heating plate is fixedly connected to the outer end of the lower tank, and an auxiliary heating pipe is provided inside the hollow heating plate. The auxiliary heating pipe is spiral-shaped, and a heat-conducting pipe is fixedly connected to the outer end of the auxiliary heating pipe. The heat-conducting pipe is located inside the lower tank and is U-shaped. A water inlet pipe and a water outlet pipe are fixedly connected to both sides of the hollow heating plate, respectively. The water inlet pipe and the water outlet pipe are fixedly connected to the two ends of the auxiliary heating pipe, respectively. A feed box is fixedly connected to one side of the upper tank, and a feed pipe is fixedly connected to the bottom end of the feed box. The feed pipe is fixedly connected to the outside of the lower tank, and a discharge pipe is fixedly connected to the bottom end of the lower tank.

[0017] A method for preparing a lithium carbonate preparation reactor includes the following steps:

[0018] Step 1: Add the lithium carbonate precipitation mother liquor to the upper tank 1 and add the precipitant. Stir for 10-15 minutes until calcium salt or magnesium salt precipitate appears at the bottom of the lithium carbonate precipitation mother liquor. Filter the precipitate to obtain mother liquor I, which enters the lower tank 2.

[0019] Step 2: Add an acidic solution to the mother liquor I inside the lower tank 2 to adjust the pH value of the mother liquor I to 2-4. Add ground lime powder to the mother liquor I and heat the lower tank 2 to 80℃-90℃ to carry out a causticization reaction to obtain mother liquor II.

[0020] Step 3: Adjust the internal temperature of the lower tank 2 to 140℃-160℃, evaporate the mother liquor II, introduce 70% lithium hydroxide solution, and then place the mother liquor II in 140℃-160℃ again. After a certain period of time, concentrate the mother liquor II to obtain mother liquor III.

[0021] Step 4: Pass a 60%-70% sodium sulfate solution (by mass of mother liquor III) into mother liquor III, stir for 12-17 minutes, and then place mother liquor III in a low-temperature environment for cold precipitation to freeze and precipitate sulfate ions, obtaining a mixed solution of sodium hydroxide and lithium hydroxide. Pass a large amount of carbon dioxide into this solution until the pH value of the mixed solution is adjusted to 2-4, obtaining a mixed solution containing sodium carbonate and lithium carbonate.

[0022] Step 5: Mix the obtained sodium carbonate and lithium carbonate solution with the extractant, stir for 5-6 minutes, let stand for 30-40 minutes, and then separate the upper sodium carbonate layer and the lower lithium carbonate layer to obtain a lithium carbonate solution.

[0023] Step six: The lithium carbonate solution obtained in step five is placed into lower tank 2 for concentration and recrystallization to obtain solid lithium carbonate.

[0024] Beneficial effects

[0025] This invention provides a lithium carbonate preparation reactor. Compared with the prior art, it has the following advantages:

[0026] (1) The lithium carbonate preparation reactor and preparation method, when feeding into the upper tank, the filter plate is rotated to make the filter plate and the filter holes inside the filter plate misaligned, thereby playing a sealing role and preventing the lithium carbonate precipitation mother liquor in the upper tank from entering the lower tank. After the lithium carbonate precipitation mother liquor is stirred, the filter plate is rotated to align with the filter holes inside the filter plate, so that the lithium carbonate precipitation mother liquor flows into the lower tank. At the same time, the filter screen in the filter plate filters the precipitate to prevent the precipitate from entering the lower tank and affecting the preparation effect of lithium carbonate. Meanwhile, the stirring blades on the inner wall of the inner cylinder rotate in the opposite direction to the upper stirring rod, so that the lithium carbonate precipitation mother liquor and the precipitant in the upper tank are fully mixed, enhancing the precipitation effect of calcium salt and magnesium salt in the mother liquor, thereby improving the purity of lithium carbonate preparation.

[0027] (2) The lithium carbonate preparation reactor and preparation method: When the lithium carbonate mother liquor is stirred and pyrolyzed, a large amount of toxic gas will be generated. The pressure generated at this time will push up the gas pressure sliding plug in the pressure relief pipe, so that the toxic gas will be discharged from the gas relief pipe into the filter cartridge for filtration. The gas is filtered and then discharged to prevent the toxic gas from polluting the environment. The hollow heat treatment vessel has a spiral auxiliary heat pipe inside that can transfer heat from the outer wall of the lower tank to the inside. The U-shaped heat conduction pipe enhances the heat transfer efficiency, thereby facilitating the rapid heating or cooling of the mother liquor in the lower tank. Attached Figure Description

[0028] Figure 1 This is a perspective view of the external structure of the present invention;

[0029] Figure 2 This is a schematic diagram of the internal structure of the upper and lower cans of the present invention;

[0030] Figure 3 This is a schematic diagram of the connection structure between the filter plate and the card plate of the present invention;

[0031] Figure 4 This is a schematic diagram of the connection structure between the rotating shaft and the sleeve rod of the present invention;

[0032] Figure 5 This is a schematic diagram of the connection structure of the transmission bevel gear, the first transmission bevel gear and the second transmission bevel gear of the present invention;

[0033] Figure 6 This is a schematic diagram of the internal structure of the vent pipe of the present invention;

[0034] Figure 7 This is a schematic diagram of the hollow heating plate of the present invention;

[0035] Figure 8 This is a side view of the present invention.

[0036] In the diagram: 1. Upper tank; 2. Lower tank; 3. Filter assembly; 301. Filter plate; 302. Positioning ring; 303. Clamping plate; 304. Filter screen; 305. Outer shell; 306. Rotating plate; 4. Clamping ring; 5. Inner cylinder; 6. Stirring blade; 7. Rotating shaft; 8. Sleeve rod; 9. Upper stirring rod; 10. Assembly box; 11. Servo motor; 12. Transmission bevel gear; 13. First driven bevel gear; 14. Second driven bevel gear. 15. Moving bevel gear; 16. Fixed ring; 17. Lower stirring rod; 18. Scraper; 19. Pressure relief pipe; 20. Air pressure slide plug; 21. Push rod; 22. Spring; 23. Air hole; 24. Vent pipe; 25. Filter cartridge; 26. Exhaust pipe; 27. Hollow heating plate; 28. Auxiliary heating pipe; 29. ​​Heat conducting pipe; 30. Water inlet pipe; 31. Water outlet pipe; 32. Feed box; 33. Feed pipe; 34. Discharge pipe. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1:

[0039] Please see Figure 1-3 A lithium carbonate preparation reactor includes an upper tank 1 and a lower tank 2, which are fixedly connected. A filter assembly 3 is provided at the connection between the upper tank 1 and the lower tank 2. The filter assembly 3 includes a filter plate 301 fixedly connected to the inner wall of the upper tank 1. A positioning ring 302 is fixedly connected to the inner wall of the lower tank 2. A clamping plate 303 is rotatably connected inside the positioning ring 302. Filter holes are opened inside both the filter plate 301 and the clamping plate 303. The clamping plate 303 is rotatably connected to the inside of the filter plate 301. A filter screen 304 is fixedly connected to the filter holes of the filter plate 301. A shell 305 is fixedly connected to one side of the lower tank 2. A rotating plate 306 is rotatably connected inside the shell 305. The rotating plate 306 is fixedly connected to the clamping plate 303.

[0040] In this embodiment, the upper tank 1 is used for the pretreatment step of the lithium carbonate precipitation mother liquor, and the lower tank 2 is used for the further treatment of the filtered mother liquor. First, the rotating plate 306 inside the outer shell 305 is rotated, so that the rotating plate 306 drives the clamping plate 303 to rotate in the positioning ring 302. The clamping plate 303 rotates on the bottom side of the filter plate 301, and the filter holes inside the filter plate 301 and the clamping plate 303 are misaligned. Then, the lithium carbonate precipitation mother liquor is introduced into the upper tank 1, and a precipitant is added to the lithium carbonate precipitation mother liquor in the upper tank 1. At the same time, the mixture is stirred to precipitate the calcium and magnesium salts inside the lithium carbonate precipitation mother liquor. After precipitation, the clamping plate 303 is rotated so that the filter holes of the filter plate 301 and the clamping plate 303 are aligned. At this time, the mother liquor I after filtration of the lithium carbonate precipitation mother liquor enters the lower tank 2. The filter screen 304 in the filter plate 301 filters the precipitate to prevent the precipitate from entering the lower tank 2.

[0041] The filter holes inside the filter plate 301 and the card plate 303 are at an angle of 40°. The pore size of the filter screen 304 is 0.7-1.2 cm. The cross-sections of the filter plate 301 and the card plate 303 are both trapezoidal.

[0042] In this embodiment, the 40° angle allows for easy rotation and adjustment of the opening and closing angle of the filter holes in the clamping plate 303 and the filter plate 301, facilitating control of the flow rate and velocity of the lithium carbonate precipitation mother liquor in the upper tank 1. The filter screen 304, with a pore size of 0.7-1.2 cm, can fully filter the calcium and magnesium salt precipitates in the lithium carbonate precipitation mother liquor, preventing the precipitates from entering the lower tank 2. The trapezoidal filter plate 301 and clamping plate 303 can prevent the lithium carbonate precipitation mother liquor from accumulating at the bottom of the inner cavity of the upper tank 1.

[0043] Example 2:

[0044] Please see Figure 1-8 This embodiment provides a technical solution based on embodiment one: the upper tank 1 is symmetrically and fixedly connected with retaining rings 4, and an inner cylinder 5 is rotatably connected between the two retaining rings 4. The inner wall of the inner cylinder 5 is symmetrically and fixedly connected with stirring blades 6, and the stirring blades 6 have through holes inside.

[0045] In this embodiment, the inner cylinder 5 rotates inside the two retaining rings 4, causing the stirring blade 6 in its inner wall to rotate. The stirring blade 6 plays the role of stirring the mother liquor I. The through hole inside the stirring blade 6 reduces the resistance encountered by the stirring blade 6 and enhances the stirring effect of the stirring blade 6.

[0046] A rotating shaft 7 is rotatably connected inside the upper tank 1 and the lower tank 2. A sleeve rod 8 is movably connected to the outer end of the rotating shaft 7. The sleeve rod 8 is fixedly connected to the inner cylinder 5. An upper stirring rod 9 is fixedly connected to the outer end of the rotating shaft 7. The upper stirring rod 9 is located inside the inner cylinder 5 and is displaced from the stirring blade 6. An assembly box 10 is fixedly connected to the top of the upper tank 1. A servo motor 11 is fixedly connected to one side of the assembly box 10. Both the rotating shaft 7 and the sleeve rod 8 are rotatably connected inside the assembly box 10. A first driven bevel gear 13 is fixedly connected to the outer end of the rotating shaft 7. A second driven bevel gear 14 is fixedly connected to the outer end of the sleeve rod 8. A transmission bevel gear 12 is fixedly connected to the output end of the servo motor 11. The transmission bevel gear 12 is located between the first driven bevel gear 13 and the second driven bevel gear 14 and meshes with each other.

[0047] In this example, after adding a precipitant to the lithium carbonate precipitation mother liquor in the upper tank 1, the servo motor 11 drives the transmission bevel gear 12 to rotate inside the assembly box 10. The rotating transmission bevel gear 12 drives the first driven bevel gear 13 and the second driven bevel gear 14 to rotate simultaneously, so that the rotation direction of the rotating shaft 7 and the sleeve rod 8 is opposite, thereby causing the stirring blade 6 and the upper stirring rod 9 to rotate in opposite directions, improving the stirring effect of the lithium carbonate precipitation mother liquor, enhancing the precipitation effect of calcium and magnesium salts in the lithium carbonate precipitation mother liquor, and improving the purity of lithium carbonate preparation.

[0048] A fixing ring 15 is fixedly connected to the inner wall of the lower tank 2. The rotating shaft 7 is rotatably connected to the fixing ring 15. Specifically, the fixing ring 15 has a locking hole in the center, and the rotating shaft 7 passes through the locking hole in the center of the fixing ring 15. A groove is provided at the connection between the rotating shaft 7 and the fixing ring 15. The groove of the rotating shaft 7 is engaged with the fixing ring 15. While allowing the rotating shaft 7 and the fixing ring 15 to rotate, the fixing ring 15 provides support for the lower half of the rotating shaft 7. The side of the rotating shaft 7 away from the upper stirring rod 9 is fixedly connected to the lower stirring rod 16. A scraper 17 is fixedly connected to the outer side of the bottom end of the rotating shaft 7. The bottom side of the scraper 17 is arc-shaped.

[0049] In this embodiment, the lower stirring rod 16 is used to stir the mother liquor I in the lower tank 2. At the same time, the lower stirring rod 16 can improve the uniformity of heating and cooling of the mother liquor. The scraper 17 is not only used to clean the bottom of the lower tank 2, but also to make the subsequently prepared mother liquor III uniformly heated, concentrated and recrystallized.

[0050] A pressure relief pipe 18 is fixedly connected to the top of the upper tank 1. A pressure relief plug 19 is slidably connected inside the pressure relief pipe 18. A push rod 20 is fixedly connected to the top of the pressure relief plug 19. The push rod 20 is slidably connected to the pressure relief pipe 18. A spring 21 is fixedly connected between the push rod 20 and the pressure relief pipe 18. An air hole 22 is opened on the side wall of the pressure relief pipe 18.

[0051] In this example, during the preparation of lithium carbonate, a large amount of toxic gas is generated during the stirring of the mother liquor and the pyrolysis process. The gas will increase the pressure of the tank and needs to be released periodically. When the pressure in the upper tank 1 is too high, the gas pressure will periodically release the gas pressure slide plug 19 inside the pressure relief pipe 18, so that the gas is discharged from the vent 22 on the side wall of the pressure relief pipe 18. After the pressure is released, the stretched spring 21 contracts. At this time, the push rod 20 drives the gas pressure slide plug 19 to slide down, and the sliding gas pressure slide plug 19 seals the vent 22.

[0052] The top end of the pressure relief pipe 18 is fixedly connected to the vent pipe 23, and the other end of the vent pipe 23 is fixedly connected to the filter cartridge 24. The filter cartridge 24 has an activated carbon layer inside, and the bottom end of the filter cartridge 24 is fixedly connected to the exhaust pipe 25.

[0053] In this embodiment, the toxic gas is discharged from the vent pipe 23 into the filter cartridge 24. The activated carbon layer in the filter cartridge 24 adsorbs the toxic gas, and the treated gas is discharged from the exhaust pipe 25 to prevent the toxic gas from polluting the environment.

[0054] A hollow heating plate 26 is fixedly connected to the outer end of the lower tank 2. An auxiliary heating pipe 27 is provided inside the hollow heating plate 26. The auxiliary heating pipe 27 is spiral-shaped. A heat-conducting pipe 28 is fixedly connected to the outer end of the auxiliary heating pipe 27. The heat-conducting pipe 28 is located inside the lower tank 2 and is U-shaped. A water inlet pipe 29 and a water outlet pipe 30 are fixedly connected to both sides of the hollow heating plate 26, respectively. The water inlet pipe 29 and the water outlet pipe 30 are fixedly connected to the two ends of the auxiliary heating pipe 27, respectively. A feed box 31 is fixedly connected to one side of the upper tank 1. A feed pipe 32 is fixedly connected to the bottom end of the feed box 31. The feed pipe 32 is fixedly connected to the outside of the lower tank 2. A discharge pipe 33 is fixedly connected to the bottom end of the lower tank 2.

[0055] In this embodiment, when the mother liquor in the lower tank 2 is used to prepare lithium carbonate, it needs to be heated and cooled. When heating or cooling, hot water or cooling water is introduced into the auxiliary heat pipe 27. The spiral auxiliary heat pipe 27 increases the heat-receiving area outside the lower tank 2 and improves the heat transfer efficiency. The heat-conducting pipe 28 can quickly transfer heat to the inside of the lower tank 2, accelerating the heating or cooling speed of the mother liquor in the lower tank 2.

[0056] Example 3:

[0057] Please see Figure 1-8 This embodiment provides a technical solution based on Embodiment 1 and Embodiment 2:

[0058] The method for preparing lithium carbonate includes the following steps:

[0059] Step 1: Add the lithium carbonate precipitation mother liquor to the upper tank 1 and add the precipitant. Stir for 10-15 minutes until calcium salt or magnesium salt precipitate appears at the bottom of the lithium carbonate precipitation mother liquor. Rotate the clamping plate 303 on the bottom side of the filter plate 301 to align the filter plate 301 with the filter holes of the clamping plate 303. At this time, the filter screen 304 inside the filter plate 301 filters the calcium salt or magnesium salt. The filtered precipitate is used to obtain mother liquor I, which enters the lower tank 2.

[0060] Step 2: Add an acidic solution to the mother liquor I inside the lower tank 2 to adjust the pH value of the mother liquor I to 2-4. Add ground lime powder to the mother liquor I and heat the lower tank 2 to 80℃-90℃ to carry out a causticization reaction to obtain mother liquor II.

[0061] Step 3: Adjust the internal temperature of the lower tank 2 to 140℃-160℃, evaporate the mother liquor II, introduce 70% lithium hydroxide solution, and then place the mother liquor II in 140℃-160℃ again. After a certain period of time, concentrate the mother liquor II to obtain mother liquor III.

[0062] Step 4: Pass a 60%-70% sodium sulfate solution (by mass of mother liquor III) into mother liquor III, stir for 12-17 minutes, and then place mother liquor III in a low-temperature environment for cold precipitation to freeze and precipitate sulfate ions, obtaining a mixed solution of sodium hydroxide and lithium hydroxide. Pass a large amount of carbon dioxide into this solution until the pH value of the mixed solution is adjusted to 2-4, obtaining a mixed solution containing sodium carbonate and lithium carbonate.

[0063] Step 5: Mix the obtained sodium carbonate and lithium carbonate solution with the extractant, stir for 5-6 minutes, let stand for 30-40 minutes, and then separate the upper sodium carbonate layer and the lower lithium carbonate layer to obtain a lithium carbonate solution.

[0064] Step six: The lithium carbonate solution obtained in step five is placed into lower tank 2 for concentration and recrystallization to obtain solid lithium carbonate.

[0065] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0066] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0067] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lithium carbonate preparation reactor, comprising an upper tank (1) and a lower tank (2), characterized in that: The upper tank (1) and the lower tank (2) are fixedly connected. A filter assembly (3) is provided at the connection between the upper tank (1) and the lower tank (2). The filter assembly (3) includes a filter plate (301) fixedly connected to the inner wall of the upper tank (1). A positioning ring (302) is fixedly connected to the inner wall of the lower tank (2). A clamping plate (303) is rotatably connected inside the positioning ring (302). Filter holes are opened inside both the filter plate (301) and the clamping plate (303). The clamping plate (303) is rotatably connected to the inside of the filter plate (301). A filter screen (304) is fixedly connected in the filter holes of the filter plate (301). A shell (305) is fixedly connected to one side of the lower tank (2). A rotating plate (306) is rotatably connected inside the shell (305). The rotating plate (306) is fixedly connected to the clamping plate (303). The upper tank (1) is symmetrically fixedly connected with retaining rings (4), and an inner cylinder (5) is rotatably connected between the two retaining rings (4). The inner wall of the inner cylinder (5) is symmetrically fixedly connected with stirring blades (6), and the stirring blades (6) have through holes inside. The upper tank (1) and the lower tank (2) are rotatably connected by a rotating shaft (7). The outer end of the rotating shaft (7) is movably connected to a sleeve rod (8). The sleeve rod (8) is fixedly connected to the inner cylinder (5). The outer end of the rotating shaft (7) is fixedly connected to an upper stirring rod (9). The upper stirring rod (9) is located inside the inner cylinder (5). The upper stirring rod (9) is displaced from the stirring blade (6). The stirring blades (6) on the inner wall of the inner cylinder (5) rotate in the opposite direction to the upper stirring rod (9).

2. The lithium carbonate preparation reactor according to claim 1, characterized in that: The filter plate (301) and the card plate (303) have a 40° angle between their internal filter holes, the filter screen (304) has a pore size of 0.7-1.2 cm, and the cross-sections of the filter plate (301) and the card plate (303) are both trapezoidal.

3. The lithium carbonate preparation reactor according to claim 1, characterized in that: An assembly box (10) is fixedly connected to the top of the upper tank (1). A servo motor (11) is fixedly connected to one side of the assembly box (10). The rotating shaft (7) and the sleeve rod (8) are rotatably connected inside the assembly box (10). A first driven bevel gear (13) is fixedly connected to the outer end of the rotating shaft (7). A second driven bevel gear (14) is fixedly connected to the outer end of the sleeve rod (8). A transmission bevel gear (12) is fixedly connected to the output end of the servo motor (11). The transmission bevel gear (12) is located between the first driven bevel gear (13) and the second driven bevel gear (14) and meshes with each other.

4. The lithium carbonate preparation reactor according to claim 1, characterized in that: The inner wall of the lower tank (2) is fixedly connected to a fixing ring (15), and the rotating shaft (7) is rotatably connected to the fixing ring (15). The side of the rotating shaft (7) away from the upper stirring rod (9) is fixedly connected to a lower stirring rod (16), and a scraper (17) is fixedly connected to the outer side of the bottom end of the rotating shaft (7). The bottom side of the scraper (17) is arc-shaped.

5. The lithium carbonate preparation reactor according to claim 1, characterized in that: The top of the upper tank (1) is fixedly connected to a pressure relief pipe (18), and a pressure slide plug (19) is slidably connected inside the pressure relief pipe (18). A push rod (20) is fixedly connected to the top of the pressure slide plug (19), and the push rod (20) is slidably connected to the pressure relief pipe (18). A spring (21) is fixedly connected between the push rod (20) and the pressure relief pipe (18). An air hole (22) is opened on the side wall of the pressure relief pipe (18).

6. The lithium carbonate preparation reactor according to claim 5, characterized in that: The top end of the pressure relief pipe (18) is fixedly connected to the vent pipe (23), and the other end of the vent pipe (23) is fixedly connected to the filter cartridge (24). The filter cartridge (24) has an activated carbon layer inside, and the bottom end of the filter cartridge (24) is fixedly connected to the exhaust pipe (25).

7. The lithium carbonate preparation reactor according to claim 1, characterized in that: A hollow heating plate (26) is fixedly connected to the outer end of the lower tank (2). An auxiliary heating pipe (27) is provided inside the hollow heating plate (26). The auxiliary heating pipe (27) is spiral-shaped. A heat-conducting pipe (28) is fixedly connected to the outer end of the auxiliary heating pipe (27). The heat-conducting pipe (28) is located inside the lower tank (2) and is U-shaped. A water inlet pipe (29) and a water outlet pipe (30) are fixedly connected to both sides of the hollow heating plate (26). The water inlet pipe (29) and the water outlet pipe (30) are fixedly connected to the two ends of the auxiliary heating pipe (27). A feed box (31) is fixedly connected to one side of the upper tank (1). A feed pipe (32) is fixedly connected to the bottom end of the feed box (31). The feed pipe (32) is fixedly connected to the outside of the lower tank (2). A discharge pipe (33) is fixedly connected to the bottom end of the lower tank (2).

8. A method for preparing lithium carbonate, characterized in that, The reaction vessel prepared using lithium carbonate according to any one of claims 1-7 includes the following steps: Step 1: Add the lithium carbonate precipitation mother liquor to the upper tank (1) and add the precipitant. Stir for 10-15 minutes until calcium salt or magnesium salt precipitate appears at the bottom of the lithium carbonate precipitation mother liquor. Filter the precipitate to obtain mother liquor I. Mother liquor I enters the lower tank (2). Step 2: Add an acidic solution to the mother liquor I inside the lower tank (2) to adjust the pH value of the mother liquor I to 2-4, add ground lime powder to the mother liquor I, and heat the lower tank (2) to 80℃-90℃ to carry out the causticization reaction to obtain mother liquor II; Step 3: Adjust the internal temperature of the lower tank (2) to 140℃-160℃, evaporate the mother liquor II, introduce 70% lithium hydroxide solution, and then place the mother liquor II in 140℃-160℃ again. After a certain period of time, concentrate the mother liquor II to obtain mother liquor III. Step 4: Pass a 60%-70% sodium sulfate solution (by mass of mother liquor III) into mother liquor III, stir for 12-17 minutes, and then place mother liquor III in a low-temperature environment for cold precipitation to freeze and precipitate sulfate ions, obtaining a mixed solution of sodium hydroxide and lithium hydroxide. Pass a large amount of carbon dioxide into this solution until the pH value of the mixed solution is adjusted to 2-4, obtaining a mixed solution containing sodium carbonate and lithium carbonate. Step 5: Mix the obtained sodium carbonate and lithium carbonate solution with the extractant, stir for 5-6 minutes, let stand for 30-40 minutes, and then separate the upper sodium carbonate layer and the lower lithium carbonate layer to obtain a lithium carbonate solution. Step six: The lithium carbonate solution obtained in step five is placed into the lower tank (2) for concentration and recrystallization to obtain solid lithium carbonate.

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