Recovery system and recovery method for lithium-iron-phosphate precursor slurry iron-discharge sewage

Abstract

A recovery system and a recovery method for lithium-iron-phosphate precursor slurry iron-discharge sewage. The recovery system comprises a first filter (4), a pipeline iron remover (5) and a second filter (8), which are connected in sequence, in the movement direction of lithium-iron-phosphate precursor slurry iron-discharge sewage (1). The recovery system can effectively treat the lithium-iron-phosphate precursor slurry iron-discharge sewage (1), realizing filter cake recovery and filtrate reuse, wherein recovered pure water is recycled to reduce the manufacturing cost of the pure water, and the sewage that has been treated by means of the system can be recovered for production line dosing or cleaning equipment, thereby achieving zero discharge of production line sewage.

Description

A recovery system and method for iron wastewater from lithium iron phosphate precursor slurry Technical Field

[0001] The present disclosure belongs to the field of lithium iron phosphate production process, and particularly relates to a system and method for recovering iron wastewater discharged from lithium iron phosphate precursor slurry. Background Art

[0002] Lithium-ion batteries are widely used due to their energy storage, rapid charge and discharge, long cycle life, and environmental friendliness. Cathode materials are a key factor in determining lithium-ion battery performance. Currently, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, and ternary cathode materials are the main commercially available materials, primarily used in the 3C (3D consumer electronics) industry, power batteries, and energy storage sectors.

[0003] In the production process of lithium iron phosphate, the front-end slurry sand grinding, iron removal and other processes will generate a large amount of wastewater for cleaning magnetic rods and cleaning equipment. The solid components in the wastewater are mainly iron phosphate and lithium carbonate, and the solid components in the wastewater exist in the form of suspension. The existing technology often adopts the treatment method of adding flocculants-plate and frame filtration-digestion-RO membrane filtration for treatment. However, the existing production line has a large amount of iron-discharged wastewater discharge, the sewage treatment station has a high cost, the amount of chemicals used is large, and the recycled wastewater cannot be recycled for use in the production line due to the impurities introduced by the use of chemicals, resulting in serious waste of pure water and materials in the iron-discharged slurry.

[0004] Therefore, designing a new type of recovery system for treating iron wastewater discharged from lithium iron phosphate precursor slurry and achieving zero wastewater discharge in a low-cost manner is a hot research direction at present.

[0005] Summary of the Invention

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] In response to the shortcomings of the existing technology, the purpose of the present disclosure is to provide a system and method for recovering iron-discharged wastewater from lithium iron phosphate precursor slurry. The recovery system designed in the present disclosure can effectively treat the iron-discharged wastewater from lithium iron phosphate precursor slurry, realize filter cake recovery and filtrate reuse, and recycle pure water for reuse to reduce pure water production costs. The wastewater treated by the system can be recycled for production line ingredients or cleaning equipment, achieving zero discharge of production line wastewater.

[0008] To achieve this purpose, the present disclosure adopts the following technical solutions:

[0009] In a first aspect, the present disclosure provides a recovery system for iron-discharged wastewater from lithium iron phosphate precursor slurry, wherein the recovery system includes a first filter, a pipeline iron remover, and a second filter connected in sequence along the movement direction of the iron-discharged wastewater from the lithium iron phosphate precursor slurry.

[0010] The recovery system designed in the present disclosure can effectively treat the iron-discharged wastewater of lithium iron phosphate precursor slurry, realize filter cake recovery and filtrate reuse, and recycle pure water to reduce the pure water manufacturing cost. The wastewater treated by this system can be recycled for production line ingredients or cleaning equipment, achieving zero discharge of production line wastewater.

[0011] As an optional technical solution of the present disclosure, the first filter includes a plate-and-frame filter.

[0012] It should be noted that the plate and frame filter refers to a conventional plate and frame filter press, the filtration area of ​​which can be 40m 3 (Designed according to the sewage discharge volume), the purpose of using plate and frame filter is to achieve preliminary solid-liquid separation and remove most of the insoluble matter in the iron removal slurry suspension. The main filter cake is iron phosphate.

[0013] In one embodiment, the filter cloth of the plate and frame filter has a mesh size of 800-1200 mesh, for example, 800 mesh, 850 mesh, 900 mesh, 950 mesh, 1000 mesh, 1050 mesh, 1100 mesh, 1150 mesh, or 1200 mesh, etc. However, the mesh size is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0014] In the present disclosure, the filter cloth mesh number of the plate and frame filter is 800-1200 mesh, which can fully exert the effect of solid-liquid separation and remove most of the insoluble matter in the iron removal slurry suspension.

[0015] In one embodiment, the second filter comprises a precision filter.

[0016] It should be noted that the components of the precision filter include a filter and a filter element. The filter can be made of 316L material and the size and flow can be adapted according to the amount of sewage. The design flow can be 30t / h. The filter element can be made of polypropylene (PP), nylon (PA) or ceramic filter element. The filter element can filter out some soluble and slightly soluble iron phosphate and lithium carbonate, and can also filter out insoluble matter missed by the plate and frame filter.

[0017] In one embodiment, the precision of the precision filter is 0.1-0.5 μm, for example, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm or 0.5 μm, etc. However, the precision is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0018] In the present disclosure, the precision of the precision filter is limited to 0.1-0.5 μm, which can not only fully filter out partially soluble and slightly soluble iron phosphate and lithium carbonate, but also completely filter out insoluble matter missed by the plate and frame filter.

[0019] As an optional technical solution of the present disclosure, the pipeline iron remover is a permanent magnetic iron remover.

[0020] It should be noted that pipeline iron removers include drawer-type permanent magnetic iron removers or rotary iron removers. The purpose of using pipeline iron removers is to remove magnetic foreign matter in the pipeline to meet the requirements of production line use, such as Fe, Cr, Ni, Zn or Fe2O3.

[0021] As an optional technical solution of the present disclosure, the recovery system further includes a sewage tank, a transfer tank and a finished product tank.

[0022] In the present disclosure, the purpose of using sewage tanks, transfer tanks and finished product tanks is: the sewage tank collects sewage from the workshop, the transfer tank can collect plate and frame filtered liquid for testing, and the plate and frame filtration or magnetic anomaly exceeds the standard can be returned to the sewage tank, and the finished product tank stores the recycled water after treatment, which is convenient for use in the transportation workshop.

[0023] It should be noted that the present disclosure does not specifically limit the materials of the sewage tank, transfer tank and finished product tank. For example, they can be made of thermoplastic plastics, including polypropylene (PP) and the like.

[0024] In one embodiment, the wastewater discharged from the lithium iron phosphate precursor slurry is moved to the first filter through the wastewater tank.

[0025] It should be noted that the present disclosure does not impose any specific limitation on the volume of the sewage tank. For example, it can be 10m 3 The wastewater tank is used to store the wastewater from the lithium iron phosphate precursor slurry delivered from the workshop and transport it to the next process.

[0026] In one embodiment, the transfer tank is disposed between the pipeline iron remover and the second filter.

[0027] It should be noted that the present disclosure does not impose any specific limitation on the volume of the transfer tank. For example, it can be 10m 3 .

[0028] In the present disclosure, the transfer tank is arranged between the pipeline iron remover and the second filter. If the plate and frame filter press has filter breakage or the magnetic anomaly of the wastewater in the transfer tank exceeds the standard, the wastewater in the transfer tank can be put into the wastewater tank again for treatment.

[0029] In one embodiment, the finished product tank is disposed between the second filter and the workshop.

[0030] It should be noted that the present disclosure does not impose any specific limitation on the volume of the finished product tank. For example, it can be 10m 3 .

[0031] In the present disclosure, the finished product tank is used to store the filtrate processed by the recovery system for transporting to the workshop for reuse.

[0032] As an optional technical solution of the present disclosure, the feed port of the first filter is connected to the discharge port of the sewage tank through a feed pump.

[0033] In the present disclosure, the purpose of providing the feed pump is to transport the iron-discharging wastewater of the lithium iron phosphate precursor slurry stored in the wastewater tank to the first filter.

[0034] In one embodiment, the discharge port of the first filter is connected to the feed port of the pipeline iron remover through a pipeline.

[0035] In one embodiment, the discharge port of the transfer tank and the feed port of the precision filter are connected via a first water pump.

[0036] In the present disclosure, the purpose of providing the first water pump is to transport the filtrate stored in the transfer tank to the precision filter.

[0037] In one embodiment, a second water pump is provided between the discharge port of the finished product tank and the workshop.

[0038] In the present disclosure, the purpose of providing the second water pump is to transport the purified filtrate to the workshop for reuse.

[0039] In a second aspect, the present disclosure provides a recovery method of the lithium iron phosphate precursor slurry wastewater recovery system as described in the first aspect, the recovery method comprising the following steps:

[0040] The iron-discharging wastewater of the lithium iron phosphate precursor slurry passes through the first filter, the pipeline iron remover and the second filter in sequence, and then the treated filtrate is recycled.

[0041] It should be noted that after completing the above recovery method, the filtrate obtained must meet the following requirements: the filtrate is visually clear.

[0042] As an optional technical solution of the present disclosure, the turbidity of the treated filtrate is ≤10NTU, for example, 10NTU, 9NTU, 8NTU, 7NTU, 6NTU, 5NTU, 4NTU, 3NTU, 2NTU, or 1NTU, etc. However, the turbidity is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] It should be noted that turbidity refers to the degree of obstruction to the passage of light by a solution, which includes the scattering of light by suspended matter and the absorption of light by solute molecules. The turbidity displayed by a turbidimeter is in nephelometric units (NTUs).

[0044] As an optional technical solution of the present disclosure, the TDS of the treated filtrate is ≤150 ppm, and can be, for example, 150 ppm, 140 ppm, 130 ppm, 120 ppm, 110 ppm, 100 ppm, 90 ppm, 80 ppm, 70 ppm, 60 ppm, 50 ppm, 40 ppm, 30 ppm, 20 ppm, or 10 ppm. However, this is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0045] It should be noted that TDS refers to the total dissolved solids content in water. The higher the TDS value, the higher the total dissolved solids content in the water.

[0046] As an optional technical solution disclosed in the present invention, the solid components in the iron-discharged wastewater of the lithium iron phosphate precursor slurry include iron phosphate and lithium carbonate.

[0047] As an optional technical solution of the present disclosure, the recycling method includes the following steps:

[0048] The iron-discharging wastewater of the lithium iron phosphate precursor slurry is passed into the wastewater tank and pumped into the plate and frame filter through the plate and frame feed pump for solid-liquid separation. The filtrate after separation moves to the pipeline iron remover for demagnetization. The demagnetized filtrate moves to the transfer tank and is pumped into the precision filter through the first water pump for filter element filtration. The obtained filtrate moves to the finished product tank for storage and is pumped into the workshop through the second water pump for recycling.

[0049] The numerical range described in the present disclosure includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present disclosure no longer exhaustively lists the specific point values ​​included in the range.

[0050] Compared with the prior art, the present disclosure has the following beneficial effects:

[0051] The recovery system designed in the present disclosure can effectively treat the iron-discharged wastewater of lithium iron phosphate precursor slurry, realize filter cake recovery and filtrate reuse, and recycle pure water to reduce the pure water manufacturing cost. The wastewater treated by this system can be recycled for production line ingredients or cleaning equipment, achieving zero discharge of production line wastewater.

[0052] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0054] FIG1 is a schematic diagram of a recycling system provided in a specific embodiment of the present disclosure.

[0055] Among them, 1-lithium iron phosphate precursor slurry iron discharge wastewater; 2-wastewater tank; 3-feed pump; 4-first filter; 5-pipeline iron remover; 6-transfer tank; 7-first water pump; 8-second filter; 9-finished product tank; 10-second water pump; 11-workshop. DETAILED DESCRIPTION

[0056] It should be understood that, in the description of the present disclosure, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure. In addition, the terms "first", "second" and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined as "first", "second" and the like may explicitly or implicitly include one or more of such features. In the description of the present disclosure, unless otherwise specified, "multiple" means two or more.

[0057] It should be noted that, in the description of this disclosure, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.

[0058] The technical solution of the present disclosure will be further explained below with reference to the accompanying drawings and through specific implementation methods.

[0059] In a specific embodiment, the present disclosure provides a recovery system for iron-discharged wastewater from lithium iron phosphate precursor slurry. As shown in FIG1 , the recovery system includes a first filter 4 , a pipeline iron remover 5 , and a second filter 8 connected in sequence along the movement direction of the iron-discharged wastewater 1 from the lithium iron phosphate precursor slurry.

[0060] The recovery system designed in the present disclosure can effectively treat the iron-discharged wastewater 1 of lithium iron phosphate precursor slurry, realize filter cake recovery and filtrate reuse, and recycle pure water to reduce the pure water manufacturing cost. The wastewater treated by this system can be recycled for production line ingredients or cleaning equipment, achieving zero discharge of production line wastewater.

[0061] Furthermore, the first filter 4 is a plate-and-frame filter.

[0062] It should be noted that the plate and frame filter refers to a conventional plate and frame filter press, the filtration area of ​​which can be 40m 3 (Designed according to the sewage discharge volume), the purpose of using plate and frame filter is to achieve preliminary solid-liquid separation and remove most of the insoluble matter in the iron removal slurry suspension. The main filter cake is iron phosphate.

[0063] Furthermore, in the plate and frame filter, the filter cloth has a mesh size of 800-1200 mesh, for example, 800 mesh, 850 mesh, 900 mesh, 950 mesh, 1000 mesh, 1050 mesh, 1100 mesh, 1150 mesh or 1200 mesh, etc. However, the mesh size is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] In the present disclosure, the filter cloth mesh number of the plate and frame filter is 800-1200 mesh, which can fully exert the effect of solid-liquid separation and remove most of the insoluble matter in the iron removal slurry suspension.

[0065] Furthermore, the second filter 8 is a precision filter.

[0066] It should be noted that the components of the precision filter include a filter and a filter element. The filter can be made of 316L material and the size and flow can be adapted according to the amount of sewage. The design flow can be 30t / h. The filter element can be made of polypropylene (PP), nylon (PA) or ceramic filter element. The filter element can filter out some soluble and slightly soluble iron phosphate and lithium carbonate, and can also filter out insoluble matter missed by the plate and frame filter.

[0067] Furthermore, the precision of the precision filter is 0.1-0.5 μm, for example, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm or 0.5 μm, etc. However, the precision is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0068] In the present disclosure, the precision of the precision filter is limited to 0.1-0.5 μm, which can not only fully filter out partially soluble and slightly soluble iron phosphate and lithium carbonate, but also completely filter out insoluble matter missed by the plate and frame filter.

[0069] Furthermore, the pipeline iron remover 5 is a permanent magnetic iron remover.

[0070] It should be noted that the pipeline iron remover 5 includes a drawer-type permanent magnet iron remover or a rotary iron remover, etc. The purpose of using the pipeline iron remover 5 is to remove magnetic foreign matter in the pipeline to meet the requirements of production line use, such as Fe, Cr, Ni, Zn or Fe2O3.

[0071] Furthermore, the recovery system also includes a sewage tank 2 , a transfer tank 6 and a finished product tank 9 .

[0072] In the present disclosure, the purpose of using the sewage tank 2, the transfer tank 6 and the finished product tank 9 is: the sewage tank 2 collects the workshop sewage, the transfer tank can collect the plate and frame filtrate for testing, and the plate and frame filtration or magnetic anomaly exceeds the standard can be returned to the sewage tank 2, and the finished product tank 9 stores the recycled water after treatment, which is convenient for use in the transportation workshop 11.

[0073] It should be noted that the present disclosure does not specifically limit the materials of the sewage tank 2, the transfer tank 6 and the finished product tank 9. For example, they can be made of thermoplastic plastics, including polypropylene (PP) and the like.

[0074] Furthermore, the lithium iron phosphate precursor slurry wastewater 1 moves through the wastewater tank 2 into the first filter 4 .

[0075] It should be noted that the present disclosure does not specifically limit the volume of the sewage tank 2. For example, it can be 10m 3 The wastewater tank 2 is used to store the lithium iron phosphate precursor slurry wastewater 1 delivered from the workshop 11 and transport it to the next process.

[0076] Furthermore, the transfer tank 6 is arranged between the pipeline iron remover 5 and the second filter 8 .

[0077] It should be noted that the present disclosure does not specifically limit the volume of the transfer tank 6. For example, it can be 10m 3 .

[0078] In the present disclosure, the transfer tank 6 is arranged between the pipeline iron remover 5 and the second filter 8. If the plate and frame filter press has filter breakage or the magnetic anomaly of the sewage in the transfer tank 6 exceeds the standard, the sewage in the transfer tank 6 can be re-entered into the sewage tank 2 for treatment.

[0079] Furthermore, the finished product tank 9 is arranged between the second filter 8 and the workshop 11 .

[0080] It should be noted that the present disclosure does not specifically limit the volume of the finished product tank 9. For example, it can be 10m 3 .

[0081] In the present disclosure, the finished product tank 9 is used to store the filtrate processed by the recovery system for transporting to the workshop 11 for reuse.

[0082] Furthermore, the feed port of the first filter 4 is connected to the discharge port of the sewage tank 2 via a feed pump 3 .

[0083] In the present disclosure, the purpose of providing the feed pump 3 is to transport the lithium iron phosphate precursor slurry iron-discharged wastewater 1 stored in the wastewater tank 2 to the first filter 4 .

[0084] Furthermore, the discharge port of the first filter 4 is connected to the feed port of the pipeline iron remover 5 through a pipeline.

[0085] Furthermore, the discharge port of the transfer tank 6 is connected to the feed port of the precision filter through a first water pump 7 .

[0086] In the present disclosure, the purpose of providing the first water pump 7 is to transport the filtrate stored in the transfer tank 6 to the precision filter.

[0087] Furthermore, a second water pump 10 is provided between the discharge port of the finished product tank 9 and the workshop 11 .

[0088] In the present disclosure, the purpose of providing the second water pump 10 is to transport the purified filtrate to the workshop 11 for reuse.

[0089] In another specific embodiment, the present disclosure provides a recovery method, which uses the above-mentioned lithium iron phosphate precursor slurry iron wastewater recovery system, and the recovery method includes the following steps:

[0090] The iron-discharging wastewater of the lithium iron phosphate precursor slurry is passed into the wastewater tank and pumped into the plate and frame filter through the plate and frame feed pump for solid-liquid separation. The filtrate after separation moves to the pipeline iron remover for demagnetization. The demagnetized filtrate moves to the transfer tank and is pumped into the precision filter through the first water pump for filter element filtration. The obtained filtrate moves to the finished product tank for storage and is pumped into the workshop through the second water pump for recycling.

[0091] The technical solution of the present disclosure is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present disclosure and should not be regarded as specific limitations of the present disclosure.

[0092] Example 1

[0093] This embodiment provides a recovery method for a system for recovering iron wastewater from lithium iron phosphate precursor slurry, the recovery method comprising the following steps:

[0094] The iron wastewater from lithium iron phosphate precursor slurry is passed into a 10m 3 The PP sewage tank is pumped into the plate and frame filter through the plate and frame feed pump for solid-liquid separation. The filtrate after separation moves to the pipeline iron remover for demagnetization. The filtrate after demagnetization moves to a volume of 10m 3 The PP transfer tank is pumped into the precision filter through the first water pump for filter filtration. The filtrate moves to a volume of 10m3 The finished PP products are stored in tanks and pumped into the workshop through a second water pump for recycling;

[0095] The filtrate in the finished product tank is visually clear, and its turbidity is ≤10NTU and its TDS test value is ≤150ppm as measured by a turbidity meter.

[0096] Comparative Example 1

[0097] This comparative example provides a recovery method for a lithium iron phosphate precursor slurry wastewater recovery system, the recovery method comprising the following steps:

[0098] The iron wastewater from lithium iron phosphate precursor slurry is passed into a 10m 3 The PP sewage tank is then moved to the pipeline iron remover for demagnetization. The demagnetized filtrate moves to a volume of 10m 3 The PP transfer tank is pumped into the precision filter through the first water pump for filter filtration. The filtrate moves to a volume of 10m 3 The finished PP products are stored in tanks and pumped into the workshop through a second water pump for recycling.

[0099] The filtrate in the finished product tank was visually clear, and its turbidity was 20 NTU and the TDS test value was 200 ppm as measured by a turbidity meter.

[0100] Comparative Example 2

[0101] This comparative example provides a recovery method for a lithium iron phosphate precursor slurry wastewater recovery system, the recovery method comprising the following steps:

[0102] The iron wastewater from lithium iron phosphate precursor slurry is passed into a 10m 3 The PP sewage tank is pumped into the plate and frame filter through the plate and frame feed pump for solid-liquid separation. The filtrate after separation moves to the pipeline iron remover for demagnetization. The filtrate after demagnetization moves to a volume of 10m 3 The finished PP products are stored in tanks and pumped into the workshop through a second water pump for recycling.

[0103] The filtrate in the finished product tank was visually clear, and its turbidity was 25 NTU and its TDS test value was 250 ppm as measured by a turbidity meter.

[0104] Through the above examples and comparative examples, it can be seen that the recovery method provided by the present disclosure can effectively treat the wastewater discharged from the discharge of iron from the lithium iron phosphate precursor slurry, realize the recovery of filter cake and reuse of filtrate, and recycle pure water to reduce the cost of pure water production. The wastewater treated by the system meets the target requirements and can be recycled for production line ingredients or cleaning equipment, thus achieving zero discharge of production line wastewater. If the plate and frame filter or precision filter is reduced, the wastewater cannot be separated into solid and liquid, and flocculants need to be used for flocculation and filtration. The flocculants will introduce new impurities and cannot be reused in the workshop, resulting in serious waste of pure water and materials in the discharge of iron slurry.

Claims

1. A recovery system for iron-discharged wastewater from lithium iron phosphate precursor slurry, the recovery system comprising a first filter, a pipeline iron remover and a second filter connected in sequence along the movement direction of the iron-discharged wastewater from the lithium iron phosphate precursor slurry.

2. The recycling system according to claim 1, wherein: The first filter comprises a plate and frame filter.

3. The recovery system according to claim 2, wherein: In the plate and frame filter, the filter cloth has a mesh number of 800-1200 meshes.

4. The recovery system according to any one of claims 1 to 3, wherein: The second filter includes a precision filter.

5. The recovery system according to claim 4, wherein: The precision of the precision filter is 0.1-0.5 μm.

6. The recovery system according to any one of claims 1 to 5, wherein: The pipeline iron remover is a permanent magnetic iron remover.

7. The recovery system according to any one of claims 1 to 6, wherein: The recycling system also includes a sewage tank, a transfer tank and a finished product tank.

8. The recovery system according to claim 7, wherein: The lithium iron phosphate precursor slurry wastewater moves to the first filter through the wastewater tank.

9. The recovery system according to claim 7, wherein: The transfer tank is arranged between the pipeline iron remover and the second filter.

10. The recycling system according to claim 7, wherein: The finished product tank is arranged between the second filter and the workshop.

11. The recycling system according to any one of claims 7 to 10, wherein: The feed port of the first filter is connected to the discharge port of the sewage tank through a feed pump. Optionally, the discharge port of the first filter is connected to the feed port of the pipeline iron remover through a pipeline; Optionally, the discharge port of the transfer tank is connected to the feed port of the precision filter via a first water pump; Optionally, a second water pump is provided between the discharge port of the finished product tank and the workshop.

12. A recycling method for a lithium iron phosphate precursor slurry wastewater recycling system according to any one of claims 1 to 11, the recycling method comprising the following steps: The iron-discharging wastewater of the lithium iron phosphate precursor slurry passes through the first filter, the pipeline iron remover and the second filter in sequence, and then the treated filtrate is recycled.

13. The recycling method according to claim 12, wherein: The turbidity of the treated filtrate is ≤10NTU.

14. The recovery method according to claim 12 or 13, wherein: In the filtrate after the treatment, TDS is ≤150ppm.

15. The recycling method according to any one of claims 12 to 14, wherein: The solid components in the iron-discharging wastewater of the lithium iron phosphate precursor slurry include iron phosphate and lithium carbonate.

16. The recycling method according to any one of claims 12 to 15, wherein: The recovery method comprises the following steps: The iron-discharging wastewater from the lithium iron phosphate precursor slurry is passed into a wastewater tank and pumped into a plate and frame filter through a plate and frame feed pump for solid-liquid separation. The separated filtrate moves to a pipeline iron remover for demagnetization. The demagnetized filtrate moves to a transfer tank and is pumped into a precision filter through a first water pump for element filtration. The obtained filtrate moves to a finished product tank for storage and is pumped into a workshop through a second water pump for recycling.

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