A multi-stage continuous high-purity lithium carbonate preparation device and method

Abstract

The present invention discloses a multi-stage continuous high-purity lithium carbonate preparation device, which is a plate-and-frame filter press, specifically comprising a main support, a fixed plate fixed at the end of the main support, and a pressing plate slidably connected to the main support, a driving assembly for driving the pressing plate to move is provided between the pressing plate and the main support, and two groups of clamping mechanisms for limiting its position are also provided on the pressing plate; it also includes a plurality of filter frames installed on the main support, filter plates are installed on both sides of each of the filter frames, and a squeezing mechanism is provided between the filter plates on both sides inside each of the filter frames; in the present invention, a vacuum device is started during filtration to form a pressure difference between the inner side and the outer side of the filter plate on the filter frame connected thereto, so that the leached lithium solution passes through the filter plate faster under the action of the pressure difference, which can effectively save filtration time.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium carbonate preparation, and in particular relates to a multi-stage continuous high-purity lithium carbonate preparation device and method. Background Art

[0002] Existing methods for producing lithium carbonate generally include electrolysis, crystallization, and precipitation. The purity of the lithium carbonate obtained by the currently commonly used industrial methods for preparing high-purity lithium carbonate is not high. For the preparation of higher-purity lithium carbonate, the precipitation method is cumbersome and has a low absorption rate. The resulting lithium carbonate is of low purity, and the crude product requires additional processing.

[0003] In the preparation of lithium carbonate, the first step is to grind and leach the roasted clinker to obtain a leached lithium solution. A plate and frame filter press is typically used to separate the leached solids and liquid. Compared to other solid-liquid separation equipment, the filter cake filtered by the filter press has a higher solid content and excellent separation performance. The basic principle of solid-liquid separation is that the mixed liquid flows through the filter medium (filter plate), where solids remain and gradually accumulate on the filter plate to form a filter cake. The filtrate, on the other hand, permeates the filter cloth, becoming a clear liquid free of solids.

[0004] However, during the filtration process of the existing plate and frame filter press, the pressure difference on both sides of the filter plate is relatively low. In the process of filtration using the pressure difference, the filter cake can only retain a large amount of residual liquid, which results in a certain amount of waste after removing the filter cake. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the object of the present invention is to provide a multi-stage continuous high-purity lithium carbonate preparation device and method.

[0006] The technical solution adopted in the present invention is:

[0007] A multi-stage continuous high-purity lithium carbonate production device, which is a plate-and-frame filter press, specifically comprising a main support, a fixed plate fixed to the end of the main support, and a compression plate slidably connected to the main support, a drive assembly for driving the compression plate to move is provided between the compression plate and the main support, and two sets of clamping mechanisms for limiting its position are also provided on the compression plate;

[0008] It also includes several filter frames installed on the main body support, filter plates are installed on both sides of each filter frame, and a squeezing mechanism is provided between the filter plates on both sides inside each filter frame.

[0009] As a preferred embodiment of the present invention, the main body support includes a crossbeam for supporting the filter frame, a storage box is provided on the lower side of the main body support, and a vacuum device is provided on the storage box.

[0010] As a preferred embodiment of the present invention: two liquid inlet pipes are provided on the fixed plate, each of the liquid inlet pipes is installed with a solenoid valve, and the upper liquid inlet pipe is connected to the slurry pump and the air pressurizing device respectively through a three-phase connector.

[0011] As a preferred embodiment of the present invention: the drive assembly includes a motor and a screw rod, the motor is fixedly mounted on the main support, one end of the screw rod is fixedly connected to the output shaft of the motor, and the other end of the screw rod is threadedly connected to the clamping plate.

[0012] As a preferred embodiment of the present invention: each group of the clamping mechanism includes two clamping brackets slidably connected to the clamping plate and a double-headed telescopic cylinder fixedly connected to the clamping plate, the two clamping brackets are distributed on both sides of the beam, and the two clamping brackets are respectively fixed on the movable ends on both sides of the double-headed telescopic cylinder, and the fixed end of the double-headed telescopic cylinder is provided with a connecting port, which is connected to the vacuum device through a pipe.

[0013] As a preferred embodiment of the present invention, the filter frame is provided with hanging ears on both sides, the filter frame is provided with liquid holes along the length direction of the main body support, the interior of the filter frame is provided with interconnected liquid outlet grooves and liquid outlet holes, and the front and back sides of the filter frame are penetrated with adsorption holes.

[0014] As a preferred embodiment of the present invention, the extrusion mechanism includes an arc-shaped elastic plate, the arc-shaped elastic plate is fixedly connected to an extrusion plate on a side close to the filter plate, both ends of the arc-shaped elastic plate are rotatably connected to extrusion brackets, the extrusion brackets are slidably connected to the embedded grooves provided on the filter frame, and a reset member is provided between the extrusion brackets and the filter frame.

[0015] A multi-stage continuous method for preparing high-purity lithium carbonate, the method comprising the following steps:

[0016] S1, select lepidolite as the raw material of making, lepidolite is placed in a drying oven and dried to obtain dry lepidolite;

[0017] S2, add calcination auxiliary material to dry lepidolite and mix after drying, place in high temperature roasting furnace and roast, finally obtain roasting clinker;

[0018] S3, the roasted clinker is placed in a grinder for grinding and pulverization, and then leached, and a leached lithium solution is obtained after passing through a belt filter and a frame filter press;

[0019] S4, adding an impurity remover to the leached lithium solution, filtering out the impurity removal residue through a filter press to obtain an impurity removal liquid, adding a scavenger to the impurity removal liquid, filtering out the purification residue through a filter press to obtain a purified liquid, exchanging the purified liquid with an ion resin after microfiltration, and heating to evaporate excess water to obtain a concentrated lithium solution;

[0020] S5, taking the concentrated lithium solution and freezing it, and then centrifuging it to obtain potassium sodium thenardite and lithium solution, and adding ion resin to the lithium solution again for exchange to obtain a refined lithium solution;

[0021] S6. Adding refined sodium carbonate solution to the refined lithium solution, obtaining wet lithium carbonate and precipitated lithium solution after centrifugal separation, and washing the wet lithium carbonate with pure water to obtain qualified wet lithium carbonate;

[0022] S7. Place the qualified wet lithium carbonate in a rotary kiln for drying to remove excess water, and finally obtain the finished lithium carbonate product.

[0023] As preferred embodiment of the present invention, the preparation of the refined sodium carbonate solution in step S6 comprises the following steps:

[0024] A1. Add a solvent to sodium carbonate and stir thoroughly until the sodium carbonate is completely dissolved to obtain a sodium carbonate solution.

[0025] A2. The sodium carbonate solution is filtered through micropores and then exchanged with an ion resin to obtain a refined sodium carbonate solution.

[0026] As a preferred method of the present invention, concentrated sulfuric acid is added to the lithium precipitate solution obtained by centrifugal separation in step S6 to carry out a decarbonization reaction to obtain a decarbonization mother liquor, and then after evaporating excess water, potassium and sodium salts in the mother liquor are removed by solid-liquid separation to finally obtain a secondary concentrated mother liquor, and the secondary concentrated mother liquor is subjected to freezing, crystallization and impurity removal to obtain a frozen lithium solution, which can be mixed with the lithium solution in step S3 to prepare a refined lithium solution.

[0027] The beneficial effects of the present invention are:

[0028] 1. In the present invention, by activating the vacuum device during filtration, a pressure difference is formed between the inner side and the outer side of the filter plate on the filter frame connected thereto. Under the action of the pressure difference, the leached lithium solution passes through the filter plate faster, which can effectively save filtration time.

[0029] 2. The clamping mechanisms of the vacuum device in the present invention are interconnected and clamped on the main support under the action of the pressure difference. The friction between the clamping mechanism and the main support is used to limit the position of the clamping plate to prevent the clamping plate from being displaced and affecting the airtightness between the filter frames. The present invention can utilize the pressure difference to allow the squeezing mechanism to squeeze the remaining residue of the roasted clinker between the two filter frames inside the filter frame before removing the remaining residue of the roasted clinker after leaching between the two adjacent filter frames, so as to extract the leached lithium solution remaining in the remaining residue of the roasted clinker, thereby reducing the waste of leached lithium solution during the filtration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0031] Figure 1 It is a structural schematic diagram of the frame filter press of the present invention;

[0032] Figure 2 It is a structural schematic diagram of the main body support in the frame filter press of the present invention;

[0033] Figure 3 This is a schematic diagram of the axial structure of the clamping mechanism and the pressing plate in the frame filter press of the present invention;

[0034] Figure 4 This is a schematic diagram of the front structure of the clamping mechanism and the pressing plate in the frame filter press of the present invention;

[0035] Figure 5 This is a schematic diagram of the axial structure of the filter frame and the pressing mechanism of the frame filter press of the present invention;

[0036] Figure 6 It is a structural schematic diagram of the cross section of the filter frame and the pressing mechanism in the frame filter press of the present invention;

[0037] Figure 7 This is a structural diagram of the filter frame and filter plates in the frame filter press of the present invention;

[0038] Figure 8 It is a structural schematic diagram of the cross section of the filter frame in the frame filter press of the present invention;

[0039] Figure 9 It is a schematic diagram of the structure of the filter frame A enlarged according to the present invention;

[0040] Figure 10 It is a structural schematic diagram of the extrusion mechanism in the frame filter press of the present invention;

[0041] Figure 11 It is a schematic diagram of the steps of the method for preparing high-purity lithium carbonate of the present invention.

[0042] In the figure: 1-main support, 101-crossbeam, 2-fixed plate, 201-liquid inlet pipe, 202-solenoid valve, 3-pressing plate, 4-filter frame, 401-liquid hole, 402-hanging ear, 403-embedded groove, 404-liquid outlet groove, 405-adsorption hole, 406-liquid outlet, 5-extrusion mechanism, 501-arc elastic plate, 502-extrusion plate, 503-extrusion bracket, 504-reset part, 6-clamping mechanism, 601-clamping bracket, 602-double-head telescopic cylinder, 603-connecting port, 7-motor, 8-screw, 9-storage box, 10-vacuum device, 11-filter plate. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0044] The following combination Figure 1-10 The specific embodiment of the present invention is described. A multi-stage continuous high-purity lithium carbonate production device is a plate-frame filter press, which specifically includes a main support 1, a fixed plate 2 fixed to the end of the main support 1, and a pressing plate 3 slidably connected to the main support 1. A driving assembly for driving the pressing plate 3 to move is provided between the pressing plate 3 and the main support 1. The pressing plate 3 is also provided with two sets of clamping mechanisms 6 for limiting its position.

[0045] It also includes several filter frames 4 installed on the main support 1, with filter plates 11 installed on both sides of each filter frame 4, and an extrusion mechanism 5 is provided between the filter plates 11 on both sides inside each filter frame 4.

[0046] The main support 1 includes a crossbeam 101 for supporting the filter frame 4 . A storage box 9 is provided on the lower side of the main support 1 , and a vacuum device 10 is provided on the storage box 9 .

[0047] In the present invention, by starting the vacuum device 10 during filtration, a pressure difference can be formed between the inner side of the filter plate 11 and the outer side of the filter plate 11 on the filter frame 4 connected thereto. Under the action of the pressure difference, the leached lithium solution passes through the filter plate 11 faster, which can effectively save filtration time; at the same time, the clamping mechanism 6 interconnected with the vacuum device 10 is clamped on the main support 1 under the action of the pressure difference, and the friction force between the clamping mechanism 6 and the main support 1 is used to limit the position of the pressing plate 3 to prevent the pressing plate 3 from being displaced and affecting the airtightness between the filter frames 4; the present invention can utilize the pressure difference to allow the squeezing mechanism 5 to squeeze the roasted clinker residue between the two filter frames 4 inside the filter frame 4 before removing the residual residue of the roasted clinker after leaching between the two adjacent filter frames 4, so as to extract the leached lithium solution remaining in the residual residue of the roasted clinker, thereby reducing the waste of the leached lithium solution during the filtration process.

[0048] As a preferred embodiment of the present invention: two liquid inlet pipes 201 are provided on the fixed plate 2, each of the liquid inlet pipes 201 is installed with a solenoid valve 202, and the upper liquid inlet pipe 201 is connected to the slurry pump and the air pressurizing device respectively through a three-phase connector.

[0049] By providing an air pressurizing device, before closing the solenoid valve 202, high-pressure air is first introduced into the liquid inlet pipe 201, and the unfiltered leached lithium solution is discharged from the liquid inlet pipe 201 on the other side by the air so that no unfiltered leached lithium solution remains in the filter frame 4; then, after closing the solenoid valve 202, the vacuum device 10 is started to extract the residual leached lithium solution in the remaining residue of the roasted clinker.

[0050] As a preferred embodiment of the present invention: the driving assembly includes a motor 7 and a screw rod 8, the motor 7 is fixedly mounted on the main support 1, one end of the screw rod 8 is fixedly connected to the output shaft of the motor 7, and the other end of the screw rod 8 is threadedly connected to the clamping plate 3.

[0051] During use, the driving motor 7 drives the screw rod 8 fixed at the output end to rotate. Since the screw rod 8 is threadedly connected to the clamping plate 3, the rotation of the screw rod 8 will push the clamping plate 3 to slide along the length direction of the beam 101.

[0052] As a preferred embodiment of the present invention: each group of the clamping mechanism 6 includes two clamping brackets 601 slidably connected to the clamping plate 3 and a double-headed telescopic cylinder 602 fixedly connected to the clamping plate 3, the two clamping brackets 601 are distributed on both sides of the beam 101, and the two clamping brackets 601 are respectively fixed on the moving ends on both sides of the double-headed telescopic cylinder 602, and the fixed end of the double-headed telescopic cylinder 602 is provided with a connecting port 603, and the connecting port 603 is connected to the vacuum device 10 through a pipe.

[0053] After the solenoid valve 202 is completely closed, the vacuum device 10 is started. Since the connecting port 603 is connected to the vacuum device 10 through a pipeline, a certain pressure difference is formed between the fixed end of the double-headed telescopic cylinder 602 and the atmospheric pressure outside the double-headed telescopic cylinder 602. Under the action of atmospheric pressure, the telescopic end of the double-headed telescopic cylinder 602 will contract and drive the clamping brackets 601 on both sides to move toward the middle. Since the clamping brackets 601 are distributed on both sides of the beam 101, the beam 101 will be clamped between the two clamping brackets 601. The friction between the clamping bracket 601 and the beam 101 is used to limit the position of the clamping plate 3 to prevent the extrusion mechanism 5 in the filter frame 4 from acting on the filter residue to form a reverse force before removing the filter residue when the vacuum device 10 is started, causing the drive component clamping plate 3 to loosen and affect the filtering effect.

[0054] As a preferred embodiment of the present invention, the filter frame 4 is provided with hanging ears 402 on both sides, the filter frame 4 is provided with a liquid hole 401 along the length direction of the main support 1, the filter frame 4 is provided with a liquid outlet groove 404 and a liquid outlet hole 406 that are interconnected, and the front and back sides of the filter frame 4 are penetrated by adsorption holes 405.

[0055] The leached lithium solution that has not been filtered by the frame filter press after preliminary filtration by the belt filter is input into the frame filter press through the liquid inlet pipe 201, and the unfiltered leached lithium solution is transported between the two filter frames 4 through the liquid hole 401, and the unfiltered leached lithium solution is filtered by the filter plate 11 arranged on the filter frame 4, and the filtered leached lithium solution enters the liquid outlet trough 404 through the liquid outlet hole 406, and the end of the liquid outlet trough 404 is connected to the storage box 9, and the filtered leached lithium solution will be concentrated in the storage box 9; while filtering, the vacuum device 10 is turned on to extract the air in the storage box 9, so that the pressure between the two filter plates 11 arranged on the filter frame 4 and the outside of the filter plate 11 can form a pressure difference, so that the leached lithium solution can pass through the filter plate 11 faster under the action of the pressure difference, which can effectively save the filtration time.

[0056] As a preferred embodiment of the present invention, the extrusion mechanism 5 includes an arc-shaped elastic plate 501, and the arc-shaped elastic plate 501 is fixedly connected to an extrusion plate 502 on a side close to the filter plate 11. The two ends of the arc-shaped elastic plate 501 are rotatably connected to an extrusion bracket 503, and the extrusion bracket 503 is slidably connected to the embedded groove 403 provided on the filter frame 4. A reset member 504 is provided between the extrusion bracket 503 and the filter frame 4.

[0057] When it is necessary to remove the remaining residue of the roasted clinker after leaching between the two adjacent filter frames 4, the solenoid valve 202 is closed and the vacuum device 10 remains in the open state. As the vacuum device 10 continues to work, under the action of the pressure difference, the extrusion brackets 503 on both sides will move toward the middle, and the arc-shaped elastic plate 501 is used to push the extrusion plate 502 fixed on its upper part to squeeze the remaining residue of the roasted clinker through the filter plate 11. Such an arrangement can extract the leached lithium solution remaining in the remaining residue of the roasted clinker by extrusion, thereby reducing the waste of leached lithium solution during the filtration process.

[0058] The following combination Figure 11 The specific embodiment of the present invention is described, which is a multi-stage continuous method for preparing high-purity lithium carbonate. The method for preparing high-purity lithium carbonate comprises the following steps:

[0059] S1, select lepidolite as the raw material of making, lepidolite is placed in a drying oven and dried to obtain dry lepidolite;

[0060] S2, add calcination auxiliary material to dry lepidolite and mix after drying, place in high temperature roasting furnace and roast, finally obtain roasting clinker;

[0061] S3, the roasted clinker is placed in a grinder for grinding and pulverization, and then leached, and a leached lithium solution is obtained after passing through a belt filter and a frame filter press;

[0062] S4, adding an impurity remover to the leached lithium solution, filtering out the impurity removal residue through a filter press to obtain an impurity-removed liquid, adding a purifier to the impurity-removed liquid, filtering out the purification residue through a filter press to obtain a purified liquid, exchanging the purified liquid with an ion resin after microfiltration, and heating to evaporate excess water to obtain a concentrated lithium solution;

[0063] S5, taking the concentrated lithium solution and freezing it, and then centrifuging it to obtain potassium sodium thenardite and lithium solution, and adding ion resin to the lithium solution again for exchange to obtain a refined lithium solution;

[0064] S6. Adding refined sodium carbonate solution to the refined lithium solution, obtaining wet lithium carbonate and precipitated lithium solution after centrifugal separation, and washing the wet lithium carbonate with pure water to obtain qualified wet lithium carbonate;

[0065] S7. Place the qualified wet lithium carbonate in a rotary kiln for drying to remove excess water, and finally obtain the finished lithium carbonate product.

[0066] As preferred embodiment of the present invention, the preparation of the refined sodium carbonate solution in step S6 comprises the following steps:

[0067] A1. Add solvent to sodium carbonate and stir thoroughly until the sodium carbonate is completely dissolved to obtain a sodium carbonate solution.

[0068] A2. The sodium carbonate solution is filtered through micropores and then exchanged with an ion resin to obtain a refined sodium carbonate solution.

[0069] As a preferred method of the present invention, concentrated sulfuric acid is added to the lithium precipitate solution obtained by centrifugal separation in step S6 to carry out a decarbonization reaction to obtain a decarbonization mother liquor, and then after evaporating excess water, potassium and sodium salts in the mother liquor are removed by solid-liquid separation to finally obtain a secondary concentrated mother liquor, and the secondary concentrated mother liquor is subjected to freezing, crystallization and impurity removal to obtain a frozen lithium solution, which can be mixed with the lithium solution in step S3 to prepare a refined lithium solution.

[0070] This method involves leaching dried lepidolite after roasting to form a leached lithium solution, removing impurities from the leached lithium solution, and then exchanging it with an ion resin multiple times to obtain a refined lithium solution. A refined sodium carbonate solution formed by exchanging a sodium carbonate solution with the ion resin is then added to the refined lithium solution for reaction. The resulting wet lithium carbonate is then washed and dried to obtain a higher purity lithium carbonate product. The present invention is not limited to the aforementioned optional embodiments. Based on the teachings of the present invention, anyone can derive other various forms of products. However, regardless of any changes in shape or structure, any technical solution that falls within the scope of the claims of the present invention falls within the scope of protection of the present invention.

Claims

1. A multi-stage continuous high-purity lithium carbonate preparation device, characterized in that: The high-purity lithium carbonate preparation device is a plate-and-frame filter press, specifically comprising a main support (1), a fixed plate (2) fixed at the end of the main support (1), and a pressing plate (3) slidably connected to the main support (1), a driving assembly for driving the pressing plate (3) to move is provided between the pressing plate (3) and the main support (1), and two sets of clamping mechanisms (6) for limiting the position of the pressing plate (3) are also provided on the pressing plate (3); It also includes a plurality of filter frames (4) mounted on the main support (1), filter plates (11) being mounted on both sides of each filter frame (4), and a squeezing mechanism (5) being provided between the filter plates (11) on both sides inside each filter frame (4); The main support (1) includes a crossbeam (101) for supporting the filter frame (4), a storage box (9) is provided on the lower side of the main support (1), and a vacuum device (10) is provided on the storage box (9); each group of the clamping mechanism (6) includes two clamping brackets (601) slidably connected to the clamping plate (3) and a double-headed telescopic cylinder (602) fixedly connected to the clamping plate (3), the two clamping brackets (601) are distributed on both sides of the crossbeam (101), the two clamping brackets (601) are respectively fixed on the movable ends on both sides of the double-headed telescopic cylinder (602), and the fixed end of the double-headed telescopic cylinder (602) is provided with a connecting port (603), and the connecting port (603) is connected to the vacuum device (10) through a pipeline; The squeezing mechanism (5) comprises an arc-shaped elastic plate (501), the arc-shaped elastic plate (501) being fixedly connected to an squeezing plate (502) on a side close to the filter plate (11), the two ends of the arc-shaped elastic plate (501) being rotatably connected to squeezing brackets (503), the squeezing brackets (503) being slidably connected to an embedding groove (403) provided on the filter frame (4), and a reset member (504) being provided between the squeezing bracket (503) and the filter frame (4).

2. A multi-stage continuous high-purity lithium carbonate preparation device according to claim 1, characterized in that: Two liquid inlet pipes (201) are provided on the fixed plate (2), each of the liquid inlet pipes (201) is installed with a solenoid valve (202), and the upper liquid inlet pipe (201) is connected to a slurry pump and an air pressurizing device respectively through a three-phase connector.

3. A multi-stage continuous high-purity lithium carbonate preparation device according to claim 1, characterized in that: The drive assembly comprises a motor (7) and a screw rod (8); the motor (7) is fixedly mounted on the main support (1); one end of the screw rod (8) is fixedly connected to the output shaft of the motor (7); and the other end of the screw rod (8) is threadedly connected to the pressing plate (3).

4. A multi-stage continuous high-purity lithium carbonate preparation device according to claim 1, characterized in that: The filter frame (4) is provided with hanging ears (402) on both sides, the filter frame (4) is provided with a liquid hole (401) along the length direction of the main support (1), the filter frame (4) is provided with a liquid outlet groove (404) and a liquid outlet hole (406) that are interconnected, and the filter frame (4) is provided with adsorption holes (405) penetrating the front and rear sides of the filter frame (4).

5. A multi-stage continuous method for preparing high-purity lithium carbonate, characterized in that: The method for preparing high-purity lithium carbonate comprises the following steps: S1, select lepidolite as the raw material of making, lepidolite is placed in a drying oven and dried to obtain dry lepidolite; S2, add calcination auxiliary material to dry lepidolite and mix after drying, place in high temperature roasting furnace and roast, finally obtain roasting clinker; S3, the roasted clinker is placed in a grinder for grinding and pulverization, and then leached, and filtered through a belt filter and a plate and frame filter press in a multi-stage continuous high-purity lithium carbonate preparation device according to any one of claims 1 to 4 to obtain a leached lithium solution; S4, adding an impurity remover to the leached lithium solution, filtering out the impurity removal residue through a filter press to obtain an impurity removal liquid, adding a scavenger to the impurity removal liquid, filtering out the purification residue through a filter press to obtain a purified liquid, exchanging the purified liquid with an ion resin after microfiltration, and heating to evaporate excess water to obtain a concentrated lithium solution; S5, taking the concentrated lithium solution and freezing it, and then centrifuging it to obtain potassium sodium thenardite and lithium solution, and adding ion resin to the lithium solution again for exchange to obtain a refined lithium solution; S6. Adding refined sodium carbonate solution to the refined lithium solution, obtaining wet lithium carbonate and precipitated lithium solution after centrifugal separation, and washing the wet lithium carbonate with pure water to obtain qualified wet lithium carbonate; S7. Place the qualified wet lithium carbonate in a rotary kiln for drying to remove excess water, and finally obtain the finished lithium carbonate product.

6. A multi-stage continuous method for preparing high-purity lithium carbonate according to claim 5, characterized in that: The preparation of the refined sodium carbonate solution in step S6 comprises the following steps: A1. Add a solvent to sodium carbonate and stir thoroughly until the sodium carbonate is completely dissolved to obtain a sodium carbonate solution; A2. The sodium carbonate solution is filtered through micropores and then exchanged with an ion resin to obtain a refined sodium carbonate solution.

7. A multi-stage continuous method for preparing high-purity lithium carbonate according to claim 5, characterized in that: Concentrated sulfuric acid is added to the lithium precipitate solution obtained by centrifugal separation in step S6 to carry out a decarbonization reaction to obtain a decarbonization mother liquor. After evaporating excess water, potassium and sodium salts in the mother liquor are removed by solid-liquid separation to finally obtain a secondary concentrated mother liquor. The secondary concentrated mother liquor is frozen, crystallized and impurities are removed to obtain a frozen lithium solution. The frozen lithium solution can be mixed with the lithium solution in step S3 to prepare a refined lithium solution.

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