Treatment system of lithium extraction leachate and lithium carbonate production system

Abstract

The utility model discloses a treatment system of lithium extraction leaching liquor and lithium carbonate production system. The treatment system of lithium extraction leaching liquor includes: first reation kettle is used for dissolving potassium sulfate in lithium extraction leaching liquor and exports first liquid, first crystallizer is used for carrying out freeze crystallization treatment to first liquid and exports first solid liquid mixture, first solid liquid separator is used for carrying out solid liquid separation treatment to first solid liquid mixture and exports crude alunite and lithium extraction mother liquor, second reation kettle is used for dissolving crude alunite in solvent and exports second liquid, second crystallizer is used for carrying out freeze crystallization treatment to second liquid and exports second solid liquid mixture, second solid liquid separator is used for carrying out solid liquid separation treatment to second solid liquid mixture and exports high purity alunite and filter mother liquor, first reflux pipeline is used for conveying filter mother liquor to mix with lithium extraction mother liquor, second reflux pipeline is used for conveying filter mother liquor to second reation kettle and uses as solvent.

Description

Technical Field

[0001] This utility model relates to the technical field of lithium extraction, and more specifically, to a lithium extraction leachate treatment system and a lithium carbonate production system. Background Technology

[0002] Lithium-ion batteries, with their unparalleled advantages such as high operating voltage, long cycle life, and environmental friendliness, have seen rapid development in recent years, leading to a surge in demand for the raw material, lithium carbonate. Among the many lithium extraction methods, the lithium ore sulfuric acid process is currently a relatively mature technology and the main method for producing lithium carbonate.

[0003] Lithium ore is mainly composed of spodumene and lepidolite. The sulfuric acid process for lithium extraction mainly includes defluorination roasting, acid roasting, leaching, impurity removal, and lithium precipitation (as in patent application CN118598168A filed by the applicant on May 30, 2024). Among these, impurity removal is a key step in improving the purity of lithium carbonate. The traditional impurity removal process involves feeding the leaching solution into a neutralization tank, adding calcium oxide or calcium hydroxide to the neutralization tank to neutralize the residual acid in the acid-roasted clinker, adjusting the pH to around 6.5, and then pumping it to the pressing system for solid-liquid separation. The liquid phase is the purified liquid, and the solid phase is the impurity-removed residue.

[0004] During pH adjustment, colloidal precipitates Al(OH)3, which adsorb lithium ions, are generated. These precipitates not only directly encapsulate lithium salts but also easily clog filter pores, making dehydration difficult. This results in increased moisture content in the dehydrated residue, leading to increased lithium salt loss and further lithium loss. Therefore, the residue needs to be repeatedly washed to reduce lithium loss. However, this increases system water and energy consumption, and some of the lithium salts encapsulated in the residue are difficult to wash out, resulting in still high lithium loss. Furthermore, the Al(OH)3 resources in the residue are not fully utilized.

[0005] Converting aluminum and potassium ions in the leachate into alum through crystallization is an effective way to recover aluminum resources. However, the traditional crystallization method still involves adding potassium hydroxide to the leachate to adjust the pH to 2-3 before crystallizing at 5-25°C. This process also introduces hydroxide ions, which still carries the risk of forming colloidal precipitates. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a method and system for treating lithium extraction leachate that can efficiently recover aluminum resources from leachate, as well as a method and system for producing lithium carbonate. The technical solution is as follows:

[0007] A method for treating lithium extraction leachate includes the following steps:

[0008] Step 100: Add potassium sulfate to the lithium extraction leachate. After the potassium sulfate dissolves, the first liquid is obtained.

[0009] Step 200: The first liquid is subjected to freeze crystallization and solid-liquid separation to obtain crude alum and lithium extraction mother liquor;

[0010] Step 300: Dissolve crude alum in a solvent to obtain a second liquid;

[0011] Step 400: The second liquid is subjected to freeze crystallization and solid-liquid separation to obtain high-purity alum and filtrate mother liquor;

[0012] Specifically, at least one of the lithium ion concentration, rubidium ion concentration, and cesium ion concentration in the filtration mother liquor is monitored. When the monitored concentration is greater than or equal to the threshold, the filtration mother liquor is mixed with the lithium extraction mother liquor. When the monitored concentration is less than the threshold, the filtration mother liquor is used as a solvent for crude alum.

[0013] As a further improvement to the above-mentioned method for treating lithium extraction leachate: in step 100, potassium sulfate is dissolved at 40-90°C, and the potassium / aluminum molar ratio in the first liquid is (1-1.2):1.

[0014] As a further improvement to the above-mentioned method for treating lithium extraction leachate: in step 200, the freezing crystallization temperature is -15 to 0°C, and the solution is kept at a constant temperature for 2 to 5 hours before filtration.

[0015] As a further improvement to the above-mentioned lithium extraction leachate treatment method: in step 300, the liquid-solid ratio of solvent to crude alum is (1-2):1, and the dissolution temperature is 60-90℃; when the volume of the filtered mother liquor is insufficient, water is added as the solvent for crude alum.

[0016] As a further improvement to the above-mentioned method for treating lithium extraction leachate: in step 400, the freezing crystallization temperature is -15 to 0°C, and the solution is kept at a constant temperature for 2 to 5 hours before filtration.

[0017] As a further improvement to the above-mentioned method for treating lithium extraction leachate: the lithium ion concentration in the mother liquor is monitored; when the lithium ion concentration in the mother liquor is ≥ the threshold, the mother liquor is mixed with the lithium extraction mother liquor; when the lithium ion concentration in the mother liquor is < the threshold, the mother liquor is used as a solvent for crude alum.

[0018] As a further improvement to the above-mentioned method for treating lithium extraction leachate, the method also includes monitoring the lithium ion concentration in the lithium extraction mother liquor. When the threshold falls within the range of 0.8 to 1.2 times the lithium ion concentration in the lithium extraction mother liquor, the threshold is kept unchanged. If the threshold is exceeded, the real-time value of the lithium ion concentration in the lithium extraction mother liquor is updated to the threshold.

[0019] As a further improvement to the above-mentioned lithium extraction leachate treatment method, it also includes solid-liquid separation treatment of the second liquid before crystallization, wherein the second liquid has an SDI ≤ 1, turbidity ≤ 0.5 NUT, and SS content ≤ 0.15 mg / L.

[0020] The production method of lithium carbonate includes the following steps:

[0021] The lithium extraction leachate was treated using the above-mentioned method to obtain a mixture of filtrate mother liquor and lithium extraction mother liquor.

[0022] The mixture was subjected to impurity removal and lithium precipitation treatment to obtain lithium carbonate.

[0023] A lithium extraction leachate treatment system includes:

[0024] The first reaction vessel is used to dissolve potassium sulfate in lithium extraction leaching solution and output the first liquid;

[0025] The first crystallizer is used for freezing and crystallizing the first liquid and outputting the first solid-liquid mixture;

[0026] The first solid-liquid separator is used to separate the first solid-liquid mixture and output crude alum and lithium extraction mother liquor;

[0027] The second reaction vessel is used to dissolve crude alum in a solvent and output the second liquid;

[0028] The second crystallizer is used for the freeze crystallization of the second liquid and to output the second solid-liquid mixture;

[0029] The second solid-liquid separator is used to separate the second solid-liquid mixture and output high-purity alum and filter mother liquor;

[0030] The first return pipe is used to transport the filtered mother liquor to be mixed with the lithium extraction mother liquor;

[0031] The second reflux pipe is used to transport the filtered mother liquor to the second reaction vessel for use as a solvent.

[0032] As a further improvement to the above-mentioned lithium extraction leaching solution treatment system: the first reaction vessel is equipped with a first level gauge, a first heater, a first stirrer, a first temperature sensor, a potassium ion concentration monitor, and an aluminum ion concentration monitor.

[0033] As a further improvement to the above-mentioned lithium extraction leachate treatment system: both the first solid-liquid separator and the second solid-liquid separator are centrifugal separators.

[0034] As a further improvement to the above-mentioned lithium extraction leaching solution treatment system: the second reactor is equipped with a second level gauge, a second heater, a second stirrer, a second temperature sensor, and two inlets connected to the output ends of the second reflux pipe and the water inlet pipe, respectively.

[0035] As a further improvement to the above-mentioned lithium extraction leaching solution treatment system, it also includes a mother liquor storage tank, which is equipped with a third level gauge, a first lithium ion concentration monitor, and two drain ports connected to the input ends of the first reflux pipe and the second reflux pipe, respectively. A first solenoid valve is provided on the first reflux pipe, and a second solenoid valve is provided on the second reflux pipe.

[0036] As a further improvement to the above-mentioned lithium extraction leachate treatment system, it also includes a lithium extraction mother liquor storage tank, which is equipped with a fourth level gauge, a second ion concentration monitor, and an inlet connected to the output end of the first reflux pipe.

[0037] As a further improvement to the above-mentioned lithium extraction leachate treatment system, it also includes a third solid-liquid separator, which performs solid-liquid separation on the second liquid and outputs a clean second liquid, and the second crystallizer performs crystallization treatment on the clean second liquid.

[0038] As a further improvement to the above-mentioned lithium extraction leachate treatment system, the third solid-liquid separator is a tubular ultrafiltration unit.

[0039] The lithium carbonate production system includes the aforementioned lithium extraction leachate treatment system.

[0040] The advantages of this utility model are as follows: (1) Only potassium sulfate is used to adjust the potassium-aluminum molar ratio to achieve the concentration conditions suitable for alum crystallization, without introducing OH⁻ to adjust the pH, avoiding the risk of forming colloidal precipitates in the solution and reducing the difficulty of subsequent impurity removal. (2) The crystallization rate is increased by using the freeze crystallization process, which significantly shortens the crystallization cycle. The purity of alum is increased by using the recrystallization process, and the purity of the obtained alum can reach 99.7%. (3) The mother liquor is recycled and the flow direction of the mother liquor is controlled by concentration monitoring, which not only significantly saves water consumption, but also does not disturb the subsequent impurity removal and lithium precipitation process, achieving near-zero waste of sulfuric acid and rare metal resources.

[0041] In summary, this invention is simple, controllable, and easy to implement. It has minimal impact on the existing lithium extraction process using the sulfuric acid method from lithium ore, and can be put into use with simple modifications. It has low investment and operating costs, and the resulting alum can not only generate revenue for enterprises but also improve subsequent impurity removal efficiency and lithium yield, making it highly practical.

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. Attached Figure Description

[0043] The accompanying drawings, which form part of this utility model, are used to aid in understanding this utility model. The content provided in the drawings and the related descriptions in this utility model can be used to explain this utility model, but do not constitute an undue limitation of this utility model. In the drawings:

[0044] Figure 1 This is a schematic diagram of the first embodiment of the lithium extraction leachate treatment system of this utility model.

[0045] Figure 2 This is a schematic diagram of the second embodiment of the lithium extraction leachate treatment system of this utility model.

[0046] The relevant markings in the above figures are:

[0047] 110 - First reactor, 120 - First crystallizer, 130 - First solid-liquid separator, 210 - Second reactor, 220 - Second crystallizer, 230 - Second solid-liquid separator, 240 - Third solid-liquid separator, 310 - Filtration mother liquor storage tank, 320 - Lithium extraction mother liquor storage tank, 410 - First reflux pipe, 420 - Second reflux pipe. Detailed Implementation

[0048] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0049] The technical solutions and features provided in the various parts of this utility model, including the following description, can be combined with each other without conflict.

[0050] Furthermore, the embodiments of the present invention described below are generally only a part of the embodiments of the present invention, and not all of the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the protection scope of the present invention.

[0051] Regarding the terminology and units used in this utility model: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this utility model are intended to cover non-exclusive inclusion.

[0052] The lithium extraction leachate in this embodiment of the invention is obtained from lepidolite through defluorination roasting, acidification roasting, and leaching treatment. Its main components and contents are: lithium ions 9.40 g / L, potassium ions 10.08 g / L, and aluminum ions 11.54 g / L, with a potassium / aluminum molar ratio of approximately 0.6:1. In actual production, the fluctuation range of each component content is between 1% and 3%.

[0053] Example 1

[0054] The method for treating the lithium extraction leachate in this embodiment includes the following steps 100-400, as detailed below:

[0055] Step 100: The lithium extraction leachate is introduced into the reactor. The amount of potassium sulfate added is calculated based on the potassium / aluminum molar ratio of 1.1:1. The dissolution temperature is 80℃. The mixture is stirred until the first liquid is obtained after the potassium sulfate is dissolved.

[0056] Step 200: The first solution is placed in a crystallizer and allowed to stand at -10℃ for 2 hours for crystallization. Then, it is centrifuged to obtain crude alum and lithium extraction mother liquor. The purity of the crude alum was tested to be 85.3%. The lithium ion content in the lithium extraction mother liquor was 9.64 g / L, and the aluminum ion concentration was reduced to 4.01 g / L.

[0057] Step 300: Dissolve crude alum in a reaction vessel with a solvent-to-crude alum liquid-to-solid ratio of 1.5:1 and a dissolution temperature of 80°C. Stir until the crude alum dissolves to obtain a second liquid.

[0058] Step 400: The second solution is placed in a crystallizer and allowed to crystallize at -10℃ for 3 hours, followed by centrifugation to obtain high-purity alum and filtrate mother liquor. Testing showed that the purity of the high-purity alum was 99%.

[0059] The lithium ion concentration in the filtration mother liquor was monitored. When the lithium ion concentration in the filtration mother liquor was greater than or equal to a threshold, the filtration mother liquor was mixed with the lithium extraction mother liquor. When the lithium ion concentration in the filtration mother liquor was less than the threshold, the filtration mother liquor was used as a solvent for crude alum. The threshold was an empirical value, taken as 9 g / L.

[0060] Example 2

[0061] The method for treating the lithium extraction leachate in this embodiment includes the following steps 100-400, as detailed below:

[0062] Step 100: The lithium extraction leachate is introduced into the reactor. The amount of potassium sulfate added is calculated based on the potassium / aluminum molar ratio of 1:1. The dissolution temperature is 80℃. The mixture is stirred until the first liquid is obtained after the potassium sulfate is dissolved.

[0063] Step 200: The first solution is placed in a crystallizer and allowed to crystallize at 0°C for 5 hours. Then, it is centrifuged to obtain crude alum and lithium extraction mother liquor. The purity of the crude alum was tested to be 86.1%. The lithium ion content in the lithium extraction mother liquor was 9.61 g / L, and the aluminum ion concentration was reduced to 4.23 g / L.

[0064] Step 300: Dissolve crude alum in a reaction vessel with a solvent-to-crude alum liquid-to-solid ratio of 1:1 and a dissolution temperature of 80°C. Stir until the crude alum dissolves to obtain a second liquid.

[0065] Step 400: The second solution is placed in a crystallizer and allowed to crystallize at -5°C for 4 hours. Then, it is centrifuged to obtain high-purity alum and filtrate. The purity of the high-purity alum was tested to be 99.3%.

[0066] The lithium ion concentration in the filtration mother liquor was monitored. When the lithium ion concentration in the filtration mother liquor was greater than or equal to a threshold, the filtration mother liquor was mixed with the lithium extraction mother liquor. When the lithium ion concentration in the filtration mother liquor was less than the threshold, the filtration mother liquor was used as a solvent for crude alum. The lithium ion concentration in the lithium extraction mother liquor was monitored. When the threshold fell within 0.8 to 1.2 times the lithium ion concentration in the lithium extraction mother liquor, the threshold remained unchanged. If it exceeded the range, the real-time value of the lithium ion concentration in the lithium extraction mother liquor was updated to the threshold.

[0067] Example 3

[0068] The method for treating the lithium extraction leachate in this embodiment includes the following steps 100-400, as detailed below:

[0069] Step 100: The lithium extraction leachate is introduced into the reactor. The amount of potassium sulfate added is calculated based on the potassium / aluminum molar ratio of 1.2:1. The dissolution temperature is 80℃. The mixture is stirred until the first liquid is obtained after the potassium sulfate is dissolved.

[0070] Step 200: The first solution is placed in a crystallizer and allowed to crystallize at -15°C for 2 hours, followed by centrifugation to obtain crude alum and lithium extraction mother liquor. The purity of the crude alum was tested to be 84.2%. The lithium ion content in the lithium extraction mother liquor was 9.72 g / L, and the aluminum ion concentration was reduced to 3.89 g / L.

[0071] Step 300: Dissolve crude alum in a reaction vessel at a solvent-to-crude alum liquid-to-solid ratio of 2:1 and a dissolution temperature of 80°C. Stir until the crude alum dissolves to obtain a second liquid.

[0072] Step 400: The second solution is placed in a crystallizer and allowed to crystallize at -5°C for 4 hours. Then, it is centrifuged to obtain high-purity alum and filtrate. The purity of the high-purity alum was tested to be 99.5%.

[0073] The lithium ion concentration in the filtration mother liquor was monitored. When the lithium ion concentration in the filtration mother liquor was greater than or equal to a threshold, the filtration mother liquor was mixed with the lithium extraction mother liquor. When the lithium ion concentration in the filtration mother liquor was less than the threshold, the filtration mother liquor was used as a solvent for crude alum. The lithium ion concentration in the lithium extraction mother liquor was monitored. When the threshold fell within 0.8 to 1.2 times the lithium ion concentration in the lithium extraction mother liquor, the threshold remained unchanged. If it exceeded the range, the real-time value of the lithium ion concentration in the lithium extraction mother liquor was updated to the threshold.

[0074] Example 4

[0075] Compared with Example 1, the difference in the treatment method of lithium extraction leachate in this example is that: a tubular ultrafiltration membrane is used to perform solid-liquid separation treatment on the second liquid to obtain a second liquid with SDI≤1, turbidity≤0.5NUT, and SS content≤0.15mg / L, and then the recrystallization operation in step 400 is performed.

[0076] In this embodiment, the purity of the high-purity alum is 99.7%.

[0077] The lithium extraction leachate treatment methods of the above embodiments 1-4 are preferably, but not limited to, implemented by the lithium extraction leachate treatment system of the following embodiments 1-2.

[0078] Figure 1 This is a schematic diagram of the first embodiment of the lithium extraction leachate treatment system of this utility model.

[0079] like Figure 1 The lithium extraction leaching solution processing system shown includes a first reactor 110, a first crystallizer 120, a first solid-liquid separator 130, a second reactor 210, a second crystallizer 220, a second solid-liquid separator 230, a first reflux pipe 410, a second reflux pipe 420, a mother liquor storage tank 310, and a lithium extraction mother liquor storage tank 320.

[0080] The first reactor 110 is used to dissolve potassium sulfate in lithium extraction leaching solution and output the first liquid; the first reactor 110 is equipped with a first level gauge, a first heater, a first stirrer, a first temperature sensor, a potassium ion concentration monitor and an aluminum ion concentration monitor.

[0081] The first crystallizer 120 is used to perform freeze crystallization on the first liquid and output the first solid-liquid mixture; the first solid-liquid separator 130 is used to perform solid-liquid separation on the first solid-liquid mixture and output crude alum and lithium extraction mother liquor; the first solid-liquid separator 130 is a centrifugal separator.

[0082] The second reaction vessel 210 is used to dissolve crude alum in a solvent and output a second liquid; the second reaction vessel 210 is equipped with a second level gauge, a second heater, a second stirrer, a second temperature sensor, and two liquid inlets that are respectively connected to the output end of the second reflux pipe 420 and the water inlet pipe.

[0083] The second crystallizer 220 is used to perform freeze crystallization on the second liquid and output the second solid-liquid mixture; the second solid-liquid separator 230 is used to perform solid-liquid separation on the second solid-liquid mixture and output high-purity alum and filtrate mother liquor; the second solid-liquid separator 230 is a centrifugal separator.

[0084] The first reflux pipe 410 is used to transport the filtered mother liquor to be mixed with the lithium extraction mother liquor, and a first solenoid valve is provided on the first reflux pipe 410; the second reflux pipe 420 is used to transport the filtered mother liquor to the second reaction vessel 210 for use as a solvent, and a second solenoid valve is provided on the second reflux pipe 420.

[0085] The mother liquor storage tank 310 is equipped with a third level gauge, a first lithium ion concentration monitor, and two drain ports that are respectively connected to the input ends of the first return pipe 410 and the second return pipe 420.

[0086] The lithium extraction mother liquor storage tank 320 is equipped with a fourth liquid level gauge, a second ion concentration monitor, and an inlet connected to the output end of the first reflux pipe 410.

[0087] Figure 2 This is a schematic diagram of the second embodiment of the lithium extraction leachate treatment system of this utility model.

[0088] Based on the first embodiment, the lithium extraction leachate treatment system of this embodiment further has the following configuration: Figure 2 As shown, it also includes a third solid-liquid separator 240, which separates the second liquid into solid and liquid components and outputs a clean second liquid. The second crystallizer 220 performs crystallization treatment on the clean second liquid. The third solid-liquid separator 240 is a tubular ultrafiltration device.

[0089] An embodiment of the lithium carbonate production method of this utility model includes the following steps: First, lithium ore is subjected to defluorination roasting, acid roasting, and leaching treatment in sequence to obtain lithium extraction leachate; then, the lithium extraction leachate is treated using any of the above-described treatment methods to obtain a mixture of filtration mother liquor and lithium extraction mother liquor; then, the mixture is subjected to impurity removal treatment and lithium precipitation treatment to obtain lithium carbonate.

[0090] An embodiment of the lithium carbonate production system of this utility model includes a defluorination roasting system, an acidification roasting system, a leaching system, a treatment system for the above-mentioned lithium extraction leaching solution, a purification system, and a lithium precipitation system.

[0091] For the parts of the lithium carbonate production methods and systems described in this specification that are not specifically disclosed, the preferred, but not limited, methods and systems for defluorination roasting, acidification roasting, leaching, impurity removal and lithium precipitation disclosed in Chinese Invention Patent Application CN118598168A are preferred.

[0092] The foregoing has described the relevant content of this utility model. Those skilled in the art will be able to implement this utility model based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of this utility model without inventive effort should fall within the protection scope of this utility model.

Claims

1. A treatment system for lithium extraction leachate, characterized in that: include: The first reaction vessel (110) is used to dissolve potassium sulfate in lithium extraction leaching solution and output the first liquid; The first crystallizer (120) is used to perform freeze crystallization on the first liquid and output the first solid-liquid mixture; The first solid-liquid separator (130) is used to perform solid-liquid separation treatment on the first solid-liquid mixture and output crude alum and lithium extraction mother liquor; The second reaction vessel (210) is used to dissolve crude alum in a solvent and output the second liquid; The second crystallizer (220) is used to perform freeze crystallization on the second liquid and output the second solid-liquid mixture; The second solid-liquid separator (230) is used to perform solid-liquid separation treatment on the second solid-liquid mixture and output high-purity alum and filter mother liquor; The first return pipe (410) is used to transport the filtered mother liquor to be mixed with the lithium extraction mother liquor; The second reflux pipe (420) is used to transport the filtered mother liquor to the second reaction vessel (210) for use as a solvent.

2. The lithium extraction leachate treatment system as described in claim 1, characterized in that: The first reaction vessel (110) is equipped with a first level gauge, a first heater, a first stirrer, a first temperature sensor, a potassium ion concentration monitor, and an aluminum ion concentration monitor.

3. The lithium extraction leachate treatment system as described in claim 1, characterized in that: Both the first solid-liquid separator (130) and the second solid-liquid separator (230) are centrifugal separators.

4. The lithium extraction leachate treatment system as described in claim 1, characterized in that: The second reaction vessel (210) is equipped with a second level gauge, a second heater, a second stirrer, a second temperature sensor, and two inlets that are respectively connected to the output ends of the second reflux pipe (420) and the water inlet pipe.

5. The lithium extraction leachate treatment system as described in claim 1, characterized in that: It also includes a mother liquor storage tank (310), which is equipped with a third level gauge, a first lithium ion concentration monitor and two drain ports connected to the input ends of the first return pipe (410) and the second return pipe (420) respectively. A first solenoid valve is provided on the first return pipe (410) and a second solenoid valve is provided on the second return pipe (420).

6. The lithium extraction leachate treatment system as described in claim 1, characterized in that: It also includes a lithium extraction mother liquor storage tank (320), which is equipped with a fourth liquid level gauge, a second ion concentration monitor and an inlet connected to the output end of the first reflux pipe (410).

7. The lithium extraction leachate treatment system as described in claim 1, characterized in that: It also includes a third solid-liquid separator (240), which performs solid-liquid separation on the second liquid and outputs a clean second liquid, and the second crystallizer (220) performs crystallization treatment on the clean second liquid.

8. The lithium extraction leachate treatment system as described in claim 7, characterized in that: The third solid-liquid separator (240) is a tubular ultrafiltration unit.

9. A lithium carbonate production system, characterized in that: The treatment system includes the lithium extraction leachate as described in any one of claims 1-8.

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