Lithium iron phosphate wastewater treatment system

Abstract

The utility model provides a lithium iron phosphate wastewater treatment system, which belongs to the field of wastewater treatment, and comprises a phosphate fertilizer recovery device, and a wastewater liquid storage tank, an oxidation pretreatment unit, a first membrane treatment unit and a second membrane treatment unit which are connected in sequence, the phosphate fertilizer recovery device is connected with the oxidation pretreatment unit and the first membrane treatment unit; the oxidation pretreatment unit is used for carrying out oxidation treatment on the wastewater input into the wastewater storage tank to obtain a first mixed solution and first solid residues; the first membrane treatment unit is used for treating the first mixed solution to obtain a second mixed solution and second solid residues; the second membrane treatment unit is used for purifying the second mixed liquid to obtain recoverable clear liquid; and the phosphate fertilizer recovery device is used for recovering the first solid residue and the second solid residue which are used as phosphate fertilizers. The lithium iron phosphate wastewater treatment system provided by the utility model not only improves the wastewater treatment efficiency and effect, but also realizes resource recovery and reutilization.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and in particular to a lithium iron phosphate wastewater treatment system. Background Art

[0002] In modern industrial activities, lithium iron phosphate, as an important lithium battery material, inevitably produces wastewater containing high suspended solids, high salinity, high chemical oxygen demand (COD) and high phosphorus content during its production process. The treatment of these wastewaters is an important aspect of environmental protection work, which is related to the sustainability of industrial activities and environmental protection.

[0003] At present, the common method of treating such wastewater includes using calcium agents and flocculants to remove phosphorus and suspended solids, followed by biochemical treatment, and finally meeting the discharge requirements of environmental protection standards. Although this treatment method can reduce environmental pollution and ensure that wastewater discharge meets the standards, this process is often accompanied by a large amount of resource waste, such as organic matter and mineral resources that cannot be recycled.

[0004] The methods mentioned in conventional technologies, such as ferrous sulfate coagulation precipitation, can improve the precipitation effect to a certain extent and reduce SS (suspended solids), but it increases the output of iron sludge, resulting in more treatment steps and costs; although the electro-flocculation-electro-Fenton combined method can reduce COD, its energy consumption is extremely high, and it fails to recover precious metal elements in wastewater, resulting in waste of resources; the use of multi-stage biological and chemical treatment increases the complexity and cost of treatment, and also fails to effectively recover precious metals.

[0005] In summary, although existing technologies can achieve basic wastewater treatment and discharge standards, they generally have problems such as high energy consumption, serious waste of resources, unstable treatment efficiency and safety risks. These shortcomings not only increase operating costs, but also limit the sustainability and environmental friendliness of wastewater treatment technology. Utility Model Content

[0006] In view of the technical problems existing in the background technology, the present application provides a lithium iron phosphate wastewater treatment system, which solves the problems of high energy consumption, difficulty in meeting treatment standards and waste of resources in the treatment of lithium iron phosphate production wastewater. The lithium iron phosphate wastewater treatment system provided by the utility model can recover a large amount of valuable substances, which reduces environmental hazards on the one hand, and the by-products can also bring certain economic benefits to the enterprise.

[0007] In a first aspect, an embodiment of the present application provides a lithium iron phosphate wastewater treatment system, comprising a phosphate fertilizer recovery device, and a wastewater storage tank, an oxidation pretreatment unit, a first membrane treatment unit, and a second membrane treatment unit connected in sequence;

[0008] The phosphate fertilizer recovery device is connected to both the oxidation pretreatment unit and the first membrane treatment unit;

[0009] The oxidation pretreatment unit is used to perform oxidation treatment on the wastewater input into the wastewater storage tank, thereby obtaining an oxidized first mixed liquid and a first solid residue;

[0010] The first membrane treatment unit is used to treat the first mixed liquid by membrane separation technology to obtain a second mixed liquid and a second solid residue;

[0011] The second membrane treatment unit is used to purify the second mixed liquid to obtain a recoverable clear liquid;

[0012] The phosphate fertilizer recovery device is used to recover the first solid residue and the second solid residue as phosphate fertilizer.

[0013] In the technical scheme of the embodiment of the present application, by combining the lithium extraction technology of ore and salt lake brine, and the wastewater treatment technology together, the wastewater is recycled according to the characteristics of lithium iron phosphate production wastewater, and finally phosphate fertilizer, lithium carbonate, sodium sulfate and pure water are obtained; wherein, the recovered phosphate fertilizer and sodium sulfate have certain economic value and can be sold directly; and the obtained lithium carbonate and pure water can be reused in production, thereby solving the problems of high energy consumption, difficult treatment and waste of resources in the treatment of lithium iron phosphate production wastewater. Through the technical scheme in the embodiment of the present application, a large amount of valuable substances are recovered, which reduces environmental hazards on the one hand, and the by-products can also bring certain economic benefits to the enterprise.

[0014] In some embodiments, the oxidation pretreatment unit includes: a centrifuge, a first combined liquid storage tank, and an oxidation treatment device;

[0015] The centrifuge is connected to the wastewater storage tank and is used to perform centrifugal separation treatment on the wastewater input into the wastewater storage tank;

[0016] The first combined liquid storage tank is connected to the centrifuge; and the oxidation treatment device is connected to the centrifuge at one end and to the first combined liquid storage tank at the other end;

[0017] The first combined liquid storage tank is used to receive the remaining liquid portion after centrifugation by the centrifuge;

[0018] The oxidation treatment device is used to receive the remaining solid residue after centrifugation of the centrifuge, and to obtain the first solid residue and oxidized liquid after oxidation treatment of the solid residue, and to input the oxidized liquid into the first combined liquid storage tank to mix with the remaining liquid after centrifugation to obtain the first mixed liquid.

[0019] In this embodiment, solid-liquid separation is performed by a centrifuge, the liquid portion is collected by a first combined liquid storage tank, and the solid residue is further oxidized by a chemical reaction using an oxidation treatment device, so that metal ions and other components in the lithium iron phosphate wastewater are effectively removed, and some filtrate is recovered at the same time. This not only improves the efficiency of wastewater treatment, but also helps to recycle resources and reduce environmental pollution.

[0020] In some embodiments, the oxidation treatment device includes a first mixing reaction tank, an oxidant supplement tank assembly, and a filtering mechanism;

[0021] One end of the first mixing reaction tank is connected to the centrifuge, and the other end is connected to the filtering mechanism;

[0022] The oxidant replenishing tank assembly is connected to the first mixing reaction tank and is used to input the oxidant into the first mixing reaction tank so that the materials in the first mixing reaction tank undergo oxidation reaction during the mixing process;

[0023] The filtering mechanism is used to receive the reaction material output from the first mixing reaction tank, and can filter the reaction material to obtain the first solid residue and the oxidized liquid;

[0024] The phosphate fertilizer recovery device is connected to the filtering mechanism to recover the first solid residue generated by the filtering mechanism.

[0025] In this embodiment, the oxidant replenishing tank assembly is independently controlled to input the oxidant into the first mixing reaction tank, and after the oxidation reaction is carried out in the first mixing reaction tank, solid-liquid separation is carried out through a filtering mechanism, so that on the one hand the oxidation reaction is complete, and on the other hand, components such as metal ions in the solid residue are effectively removed, thereby improving the recovery rate.

[0026] In some embodiments, the oxidant supplement tank assembly includes a sulfuric acid output device for outputting sulfuric acid to the first mixing reaction tank and a hydrogen peroxide output device for outputting hydrogen peroxide.

[0027] In this embodiment, the input of sulfuric acid to the first mixing reaction tank is controlled by the sulfuric acid output device, and the input of hydrogen peroxide to the first mixing reaction tank is controlled by the hydrogen peroxide output device, thereby flexibly controlling the input of the oxidant to complete the oxidation reaction.

[0028] In some embodiments, the first membrane treatment unit includes an alkalization device, a solid-liquid separation device, a first membrane treatment device, and a second combined liquid storage tank connected in sequence;

[0029] The alkalization device is connected to the first combined liquid storage tank, and is used to receive the first mixed liquid output from the first combined liquid storage tank, and perform alkalization treatment on the first mixed liquid;

[0030] The solid-liquid separation device is used to perform solid-liquid separation on the first mixed liquid after alkalization treatment to obtain a second solid residue and an alkalized liquid;

[0031] The first membrane treatment device comprises a multi-media filter, an ultrafiltration device and a special membrane separation device connected in sequence, for filtering the alkalized liquid to obtain the second mixed liquid, and outputting the second mixed liquid to the second combined liquid storage tank;

[0032] The phosphate fertilizer recovery device is connected to the solid-liquid separation device to recover the second solid residue.

[0033] In this embodiment, the filtrate obtained in the previous step is alkalized by an alkalization device, so that the metal ions in the liquid generate insoluble hydroxide precipitates, and are further purified by separation and a first membrane treatment device, and input into a second combined liquid storage tank, thereby effectively reducing the metal ion concentration in the wastewater by alkalization precipitation and filtration.

[0034] In some embodiments, the alkalization device includes a second mixing reaction tank, and an alkalizing agent output device connected to the second mixing reaction tank;

[0035] The second mixing reaction tank is used to receive the first mixed liquid output from the first combined liquid storage tank;

[0036] The alkalizing agent output device stores sodium hydroxide, which is used to input sodium hydroxide into the second mixing reaction tank to alkalize the first mixed solution during the mixing process.

[0037] In this embodiment, the input of the alkalizing agent to the second mixing reaction tank is controlled by the alkalizing agent output device, so that the alkalizing reaction based on sodium hydroxide can be flexibly controlled to make the reaction complete.

[0038] In some embodiments, the first membrane treatment unit further comprises electrocatalysis and sludge disposal equipment;

[0039] One end of the electrocatalytic and sludge disposal device is connected to the first membrane treatment device to receive the concentrated liquid output by the first membrane treatment device; the other end of the electrocatalytic and sludge disposal device is connected to the second combined liquid storage tank; and the phosphate fertilizer recovery device is connected to the electrocatalytic and sludge disposal device;

[0040] The electrocatalytic and sludge treatment equipment is used to perform electrocatalytic and sludge treatment on the concentrated liquid to obtain a third solid residue and a treated liquid, and the treated liquid is input into the second combined liquid storage tank;

[0041] The phosphate fertilizer recovery device is used to recover the third solid residue.

[0042] In this embodiment, the electrocatalytic and sludge disposal equipment is used to decompose organic and inorganic matter in the wastewater by electrocatalysis, and stabilize, reduce the volume, render it harmless and recycle it as a resource, thereby improving the treatment efficiency and contributing to environmental protection and resource recovery.

[0043] In some embodiments, the second membrane treatment unit includes a softener for softening the second mixed liquid, a second membrane treatment device, and a clear liquid recovery tank for recovering recoverable clear liquid, which are connected in sequence.

[0044] In this embodiment, the second mixed liquid is softened by a softener to reduce the calcium and magnesium ion content in the water, thereby preventing these ions in the hard water from causing scaling on pipes and equipment and reducing washing efficiency.

[0045] In some embodiments, the second membrane treatment unit further comprises a metal ion treatment device;

[0046] The metal ion treatment device comprises a precipitant output device, a precipitation crystallization tank, a separation mechanism and an evaporator;

[0047] The second membrane treatment device, the precipitation crystallization tank, the separation mechanism and the evaporator are connected in sequence;

[0048] The second membrane treatment device is a reverse osmosis device;

[0049] The evaporator is connected to the clear liquid recovery tank so that the distilled water after distillation by the evaporator enters the clear liquid recovery tank;

[0050] The precipitant output device is connected to the precipitation crystallization tank and is used for inputting the precipitant into the precipitation crystallization tank.

[0051] In this embodiment, the continuous process of using the second membrane treatment device (reverse osmosis equipment), precipitation crystallization tank (precipitation crystallization treatment), separation mechanism (separation technology) and evaporator (distillation treatment) in sequence for the mixed wastewater can achieve efficient purification and resource recovery of wastewater. These steps combined provide a comprehensive solution for treating various types of wastewater, thereby providing better purification effects.

[0052] In some embodiments, the second membrane treatment unit further comprises a lithium carbonate recovery device and a sodium sulfate recovery device;

[0053] The lithium carbonate recovery device is connected to the separation mechanism to recover the first crystalline material after solid-liquid separation;

[0054] The sodium sulfate recovery device is connected to the evaporator to recover the second crystalline material generated after the evaporator is treated.

[0055] In this embodiment, the lithium carbonate recovery device is used to recover the first crystalline substance lithium carbonate, and the sodium sulfate recovery device is used to recover the second crystalline substance sodium sulfate generated by the evaporator, thereby effectively recovering the by-product substances generated during the lithium iron phosphate wastewater treatment process, further reducing the wastewater treatment cost and avoiding environmental pollution.

[0056] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0058] Figure 1 This is a schematic diagram of the overall structure and connection relationship of the lithium iron phosphate wastewater treatment system in the embodiment of the present application;

[0059] Figure 2 This is a schematic diagram of the structure and connection relationship of the oxidation pretreatment unit of the lithium iron phosphate wastewater treatment system in the embodiment of the present application;

[0060] Figure 3 This is a schematic diagram of the structure and connection relationship of the first membrane treatment unit of the lithium iron phosphate wastewater treatment system in the embodiment of the present application;

[0061] Figure 4 This is a schematic diagram of the structure and connection relationship of the second membrane treatment unit of the lithium iron phosphate wastewater treatment system in the embodiment of the present application.

[0062] Description of reference numerals:

[0063] 100, lithium iron phosphate wastewater treatment system; 1, wastewater storage tank; 2, oxidation pretreatment unit; 21, centrifuge; 22, first combined storage tank; 23, oxidation treatment device; 231, first mixed reaction tank; 232, oxidant supplement tank assembly; 2321, sulfuric acid output device; 2322, hydrogen peroxide output device; 233, filtering mechanism; 3, first membrane treatment unit; 31, alkalization device; 311, second mixed reaction tank; 312, alkalization agent output device; 32, solid-liquid separation device; 33, first membrane treatment unit Device; 331, multi-media filter; 332, ultrafiltration equipment; 333, special membrane separation equipment; 34, second combined liquid storage tank; 35, electrocatalysis and sludge disposal equipment; 4, second membrane treatment unit; 41, softener; 42, second membrane treatment device; 43, clear liquid recovery tank; 44, metal ion treatment device; 441, precipitant output device; 442, precipitation crystallization tank; 443, separation mechanism; 444, evaporator; 45, lithium carbonate recovery device; 46, sodium sulfate recovery device; 5, phosphate fertilizer recovery device.

[0064] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0065] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0067] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0068] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0069] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0070] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0071] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0072] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0073] Existing lithium iron phosphate wastewater treatment technologies generally have problems such as high energy consumption, serious waste of resources, unstable treatment efficiency and safety risks. These shortcomings not only increase operating costs, but also limit the sustainability and environmental friendliness of wastewater treatment technologies.

[0074] In order to solve the above technical problems, the present application provides a lithium iron phosphate wastewater treatment system 100, through which the lithium iron phosphate wastewater treatment system 100 solves the problems of high energy consumption, difficulty in meeting treatment standards and waste of resources in lithium iron phosphate production wastewater treatment. Through the technical solution in the embodiment of the present application, a large amount of valuable substances are recovered, which reduces environmental hazards on the one hand, and the by-products can also bring certain economic benefits to the enterprise.

[0075] The present application provides a lithium iron phosphate wastewater treatment system 100, which belongs to a wastewater treatment system and can be applied to the treatment of lithium iron phosphate production wastewater in lithium iron phosphate battery production and preparation units, or other related units. The lithium iron phosphate wastewater treatment system 100 can purify lithium iron phosphate wastewater, reduce environmental pollution, and recover a large amount of valuable substances.

[0076] For the convenience of description, the following embodiments are described by taking the lithium iron phosphate wastewater treatment system 100 of the embodiment of the present application as an example.

[0077] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a lithium iron phosphate wastewater treatment system 100 provided in some embodiments of the present application.

[0078] according to Figure 1 It can be seen that the lithium iron phosphate wastewater treatment system 100 includes a phosphate fertilizer recovery device 5, and a wastewater storage tank 1, an oxidation pretreatment unit 2, a first membrane treatment unit 3 and a second membrane treatment unit 4 connected in sequence; the phosphate fertilizer recovery device 5 is connected to both the oxidation pretreatment unit 2 and the first membrane treatment unit 3; the oxidation pretreatment unit 2 is used to oxidize the wastewater input into the wastewater storage tank 1, so as to obtain an oxidized first mixed liquid and a first solid residue; the first membrane treatment unit 3 is used to treat the first mixed liquid by membrane separation technology to obtain a second mixed liquid and a second solid residue; the second membrane treatment unit 4 is used to purify the second mixed liquid to obtain a recoverable clear liquid; the phosphate fertilizer recovery device 5 is used to recover the first solid residue and the second solid residue as phosphate fertilizer.

[0079] It should be noted that the wastewater generated during the production of lithium iron phosphate has several significant characteristics, including the following: (1) High suspended solids: The wastewater contains a high concentration of undissolved solids, including unreacted raw materials, by-products, and solid waste generated during the production process. High suspended solids content can block the filtration system and affect the efficiency of subsequent treatment processes, such as the effectiveness of the biochemical treatment system. (2) High salt: The wastewater contains a high concentration of dissolved salts, especially electrolytes and other chemical additives used in the battery manufacturing process. High salinity inhibits many biological treatment processes because most microorganisms have difficulty surviving and reproducing in a high-salt environment. (3) High COD (chemical oxygen demand): High COD indicates that there are a large number of oxidizable organic substances in the wastewater, which come from organic chemicals used in the production process or organic by-products generated by chemical reactions in the production process. High COD indicates that there are a large number of organic pollutants in the wastewater, which require a large amount of oxygen for biodegradation, and puts higher requirements on the oxygen demand and treatment capacity of the biochemical treatment system. (4) High phosphorus: Since phosphates are used in the manufacturing process of lithium iron phosphate, the phosphorus content in the wastewater is very high. Phosphorus is one of the main causes of eutrophication of water bodies. Direct discharge without treatment will seriously affect water quality, leading to excessive growth of algae and destruction of aquatic ecological balance.

[0080] These characteristics together make the treatment of lithium iron phosphate wastewater a complex task. Multi-stage treatment technologies such as chemical precipitation, flocculation, biochemical treatment and possible physical separation processes are required to ensure that all pollutants are effectively treated.

[0081] In addition, some components of wastewater, such as phosphorus and certain organic compounds, have the potential to be recycled and reused. For example, phosphorus recovered from wastewater can be used in fertilizer production, and organic matter can be recovered for energy generation or as chemical raw materials.

[0082] Therefore, although the current treatment methods can achieve standard discharge to a certain extent, there is still room for further optimization to reduce resource waste and improve economic benefits, taking into account the development of resource recovery and more efficient treatment technologies. This requires comprehensive consideration of chemical, biological and physical treatment technologies, as well as emerging resource recovery technologies.

[0083] In the lithium iron phosphate wastewater treatment system 100 provided in the present application, the wastewater storage tank 1 is used to collect lithium iron phosphate production wastewater generated during production or other related treatment processes as a raw material for the lithium iron phosphate wastewater treatment system 100, and the wastewater therein can be input into the oxidation pretreatment unit 2 under control to treat the wastewater.

[0084] As mentioned above, the oxidation pretreatment unit 2 is connected to the wastewater storage tank 1, and its purpose is to oxidize the input wastewater to decompose the oxidizable organic matter, and at the same time, it may convert some metal ions into a form that is easier to handle (such as iron oxide) through oxidation to form a first mixed liquid and produce a first solid residue that is easy to separate.

[0085] Specifically, the oxidation pretreatment unit 2 can play the following roles when treating wastewater: (1) Reducing the burden of subsequent treatment: By oxidizing and decomposing organic matter, the pollution burden of the subsequent membrane treatment unit is reduced, and the service life and efficiency of the membrane are improved. (2) Improving the properties of wastewater: Oxidation treatment can change the chemical properties of certain pollutants, making them easier to remove by physical methods such as membrane separation. (3) Enhancing the treatment efficiency of solid residues: The solid residues generated during the oxidation process are easy to separate and can be directly used in the production of phosphate fertilizers, thereby improving the recovery rate of resources.

[0086] As mentioned above, the first membrane treatment unit 3 is connected to the oxidation pretreatment unit 2. The unit uses membrane separation technology to treat the first mixed liquid in liquid state output by the oxidation pretreatment unit 2, separates the second solid residue, and further purifies the treated liquid to obtain the second mixed liquid, in preparation for the next step of deep purification.

[0087] As mentioned above, the second membrane treatment unit 4 is connected to the first membrane treatment unit 3, and the second membrane treatment unit 4 further purifies the second mixed liquid in liquid form output by the first membrane treatment unit 3, and finally obtains a recyclable clear liquid. This step uses more sophisticated membrane technology, such as nanofiltration or reverse osmosis, to ensure high-quality water recovery.

[0088] As mentioned above, the phosphate fertilizer recovery device 5 is connected to both the oxidation pretreatment unit 2 and the first membrane treatment unit 3. The device can effectively recover the solid residues (first solid residues and second solid residues) generated in these two steps, collect the residues, and convert them into phosphate fertilizers to achieve resource recycling.

[0089] The lithium iron phosphate wastewater treatment system 100 not only effectively treats wastewater by integrating multiple treatment technologies, but also achieves dual environmental and economic benefits through resource recovery. Oxidation pretreatment is a key step in the entire treatment process. It provides optimized wastewater conditions for subsequent membrane treatment and increases the possibility of resource recovery. Overall, its beneficial effects may include the following: (1) Resource recovery: By converting solid residue into phosphate fertilizer, the system not only treats wastewater, but also achieves effective waste utilization and resource recovery. (2) Multi-stage treatment: The combined use of multiple treatment units can more effectively treat wastewater with complex components, gradually reduce pollutant concentrations, and improve water recovery rates. (3) Efficient purification: The combined use of oxidation pretreatment and dual membrane systems can effectively remove organic matter, suspended matter and certain soluble pollutants in wastewater, achieving efficient purification. (4) Environmentally friendly: The design of the entire system reduces dependence on chemical additives and reduces potential environmental impacts. In short, in the technical scheme of the embodiment of the present application, by recycling the wastewater according to the characteristics of lithium iron phosphate production, phosphate fertilizer, lithium carbonate, sodium sulfate and pure water are finally obtained; among them, the recovered phosphate fertilizer and sodium sulfate have certain economic value and can be sold directly; and the obtained lithium carbonate and pure water can be reused for production, thereby solving the problems of high energy consumption, difficult treatment and waste of resources in the treatment of lithium iron phosphate production wastewater. Through the technical scheme in the embodiment of the present application, a large amount of valuable substances are recovered, which reduces environmental hazards on the one hand, and the by-products can also bring certain economic benefits to the enterprise.

[0090] For further information, please refer to Figure 2 In the embodiment of the present application, the oxidation pretreatment unit 2 includes: a centrifuge 21, a first merging liquid storage tank 22 and an oxidation treatment device 23; the centrifuge 21 is connected to the wastewater storage tank 1 to perform centrifugal separation treatment on the wastewater input into the wastewater storage tank 1; the first merging liquid storage tank 22 is connected to the centrifuge 21; and, one end of the oxidation treatment device 23 is connected to the centrifuge 21, and the other end is connected to the first merging liquid storage tank 22; the first merging liquid storage tank 22 is used to receive the remaining liquid part after centrifugation of the centrifuge 21; the oxidation treatment device 23 is used to receive the remaining solid residue part after centrifugation of the centrifuge 21, and oxidize the solid residue part to obtain the first solid residue and oxidized liquid, and the oxidized liquid is input into the first merging liquid storage tank 22 to mix with the remaining liquid part after centrifugation to obtain the first mixed liquid.

[0091] As mentioned above, the centrifuge 21 is connected to the wastewater storage tank 1 and is used to perform preliminary solid-liquid separation on the wastewater from the wastewater storage tank 1. Through high-speed rotation, the centrifuge 21 can effectively separate the solid particles (such as unreacted chemicals, sediments, etc., i.e., the solid residue part) from the liquid (i.e., the remaining liquid part) in the wastewater.

[0092] Centrifugal separation is an effective way to treat wastewater with high suspended matter. It can quickly and effectively separate a large number of solid particles, reduce the load of subsequent treatment units, and improve the processing capacity and efficiency of the entire system.

[0093] As mentioned above, the first combined liquid storage tank 22 is connected to the centrifuge 21 to receive the remaining liquid after centrifugation and wait to be mixed with the oxidized liquid to ensure the continuous flow and caching of the liquid during the treatment process, providing a basis for subsequent mixing and chemical treatment.

[0094] As mentioned above, the oxidation treatment device 23 is connected to the centrifuge 21 at one end and to the first combined liquid storage tank 22 at the other end. It treats the solid residue obtained after centrifugation by adding an oxidant (such as hydrogen peroxide) to decompose organic matter, transform the state of heavy metals, etc., thereby improving the chemical properties of the residue, making it easier to handle and transform it into useful resources such as fertilizers. At the same time, the generated oxidized liquid can be mixed with the remaining liquid in the first combined liquid storage tank 22 for further treatment.

[0095] Oxidation treatment can effectively degrade organic matter, transform the chemical state of heavy metals, and reduce the environmental risks of harmful substances. In addition, oxidation treatment helps to improve the biodegradability of wastewater and provide better conditions for biochemical treatment.

[0096] In summary, the system can effectively deal with the complex pollution problem of lithium iron phosphate wastewater through structural optimization and detailed process configuration, while realizing resource recovery and reuse, with significant environmental and economic benefits.

[0097] Furthermore, in an embodiment of the present application, the oxidation treatment device 23 includes a first mixing reaction tank 231, an oxidant replenishing tank assembly 232 and a filtering mechanism 233; one end of the first mixing reaction tank 231 is connected to the centrifuge 21, and the other end is connected to the filtering mechanism 233; the oxidant replenishing tank assembly 232 is connected to the first mixing reaction tank 231, and is used to input an oxidant into the first mixing reaction tank 231, so that the material in the first mixing reaction tank 231 undergoes an oxidation reaction during the mixing process; the filtering mechanism 233 is used to receive the reaction material output from the first mixing reaction tank 231, and can filter the reaction material to obtain the first solid residue and the oxidized liquid; the phosphate fertilizer recovery device 5 is connected to the filtering mechanism 233, and is used to recover the first solid residue generated by the filtering mechanism 233.

[0098] As mentioned above, the first mixing reaction tank 231, one end of which is connected to the centrifuge 21 and the other end of which is connected to the filtering mechanism 233, serves as the main reaction container in the oxidation pretreatment process, and is used to ensure sufficient contact and reaction between the oxidant and the solid residue, to enhance the efficiency and integrity of the oxidation reaction, and to help more thoroughly decompose the organic and inorganic pollutants in the wastewater.

[0099] The first mixing reaction tank 231 ensures that the oxidant has sufficient contact time and reaction area with the pollutants in the wastewater, and is a key equipment for achieving efficient oxidation treatment.

[0100] As mentioned above, the oxidant replenishing tank assembly 232 provides the necessary oxidants (sulfuric acid and hydrogen peroxide) to ensure the progress of the reaction. By using strong oxidants, the capacity of oxidation treatment is increased, thereby more effectively removing pollutants in the wastewater, especially those organic substances that are difficult to biodegrade.

[0101] As mentioned above, after the oxidation reaction is completed, the filter mechanism 233 physically filters the reaction product to separate the solid residue and the oxidized liquid, thereby ensuring that the solid residue and the oxidized liquid are effectively separated, so that the solid residue can be directly used for phosphate fertilizer recovery, and the clean oxidized liquid can be further processed or discharged in compliance with standards. The filter mechanism 233 provides an effective separation means for the oxidized material, ensuring that the treated solid and liquid can be subsequently processed or utilized according to different uses and processing requirements.

[0102] Furthermore, in the embodiment of the present application, the oxidant replenishing tank assembly 232 includes a sulfuric acid output device 2321 for outputting sulfuric acid to the first mixing reaction tank 231 and a hydrogen peroxide output device 2322 for outputting hydrogen peroxide.

[0103] As mentioned above, the oxidant replenishing tank assembly 232 includes two parts, namely, a sulfuric acid output device 2321 and a hydrogen peroxide output device 2322. There are specific reasons and advantages for using sulfuric acid and hydrogen peroxide as oxidants in the lithium iron phosphate wastewater treatment system 100, especially when treating wastewater with characteristics such as high COD, high suspended solids, high salt and high phosphorus.

[0104] The sulfuric acid output device 2321 is used to control the output of sulfuric acid to the first mixing reaction tank 231, and its function is:

[0105] For pH adjustment: Sulfuric acid is a strong acid that can effectively adjust the pH value of wastewater. In many chemical treatment processes, a specific pH value is required to optimize the efficiency and selectivity of the reaction.

[0106] Use as a precipitant: Sulfuric acid can be used to precipitate heavy metals in wastewater, such as iron, aluminum, etc. By forming sulfate precipitates, such as iron sulfate (Fe2(SO4)3), these precipitates can be effectively removed by the filtration mechanism 233, thereby reducing the pollutant burden in the wastewater.

[0107] Used to enhance oxidation reactions: When treating wastewater containing organic matter, an acidic environment can increase the rate and thoroughness of the oxidation reaction, especially when used in combination with hydrogen peroxide.

[0108] The hydrogen peroxide output device 2322 is used to control the output of hydrogen peroxide to the first mixing reaction tank 231, and its function is:

[0109] As a strong oxidant: hydrogen peroxide (H 2 O 2 ) is a strong oxidant that can effectively oxidize organic pollutants and some inorganic pollutants in wastewater. It can decompose the difficult-to-degrade organic matter in wastewater, such as dyes, surfactants, etc., and convert them into smaller, easier to handle or biodegradable molecules.

[0110] No residue: Hydrogen peroxide decomposes into water and oxygen after the reaction, leaving no harmful chemical residues, which is environmentally friendly and reduces the risk of secondary pollution.

[0111] Synergistic effect: When used in combination with sulfuric acid, the oxidation effect of hydrogen peroxide can be further enhanced. The acidic environment provided by sulfuric acid can promote the decomposition of hydrogen peroxide, releasing more oxidative free radicals, thereby improving the oxidation efficiency.

[0112] Lithium iron phosphate wastewater usually contains high concentrations of organic compounds, metal ions and phosphorus, which can be effectively controlled and removed through oxidation treatment with sulfuric acid and hydrogen peroxide. Especially in the treatment of high COD environment, the addition of hydrogen peroxide can significantly improve the removal rate of organic matter, while sulfuric acid helps to adjust pH and precipitate metal ions, and can also remove phosphorus through the formation of sulfate.

[0113] In summary, the combined use of sulfuric acid and hydrogen peroxide can not only efficiently treat the complex components in lithium iron phosphate wastewater, but also achieve the expected treatment effect in an environmentally friendly way. This method takes into account efficiency, safety and environmental protection, and is a common and effective strategy in industrial wastewater treatment.

[0114] For further information, please refer to Figure 3In the embodiment of the present application, the first membrane treatment unit 3 includes an alkalization device 31, a solid-liquid separation device 32, a first membrane treatment device 33, and a second combined liquid storage tank 34 connected in sequence; the alkalization device 31 is connected to the first combined liquid storage tank 22, for receiving the first mixed liquid output by the first combined liquid storage tank 22, and alkalizing the first mixed liquid; the solid-liquid separation device 32 is used to perform solid-liquid separation on the first mixed liquid after alkalization to obtain a second solid residue and an alkalized liquid; the first membrane treatment device 33 includes a multi-media filter 331, an ultrafiltration device 332 and a special membrane separation device 333 connected in sequence, for filtering the alkalized liquid to obtain the second mixed liquid, and output it to the second combined liquid storage tank 34; the phosphate fertilizer recovery device 5 is connected to the solid-liquid separation device 32 to recover the second solid residue.

[0115] The above features provide detailed refinement and optimization of the first membrane treatment unit 3 in the lithium iron phosphate wastewater treatment system 100, including the detailed configuration of the alkalization device 31, the solid-liquid separation device 32, the first membrane treatment device 33, and the second combined liquid storage tank 34. The integration of these components is intended to improve wastewater treatment efficiency, optimize resource recovery, and ensure that the treated water quality meets the standards for discharge or further use.

[0116] As mentioned above, the alkalization device 31 is used to adjust the pH value of the wastewater, which is usually achieved by adding alkali (such as sodium hydroxide). This step is mainly used to neutralize the acidic wastewater that may be produced in the previous step, and at the same time promote the precipitation of certain heavy metals and phosphorus. Alkalization treatment can reduce the concentration of metal ions in the wastewater, especially by forming insoluble metal hydroxide precipitates (such as iron hydroxide and aluminum hydroxide), thereby reducing the bioavailability and toxicity of these metals. Alkalization treatment is simple and effective, and can significantly improve the efficiency of subsequent membrane treatment units and protect membrane materials, preventing membrane damage caused by abnormal pH.

[0117] As mentioned above, the solid-liquid separation device 32 performs solid-liquid separation in the alkalized mixed liquid, which usually involves using a settling tank, a filter or a centrifuge to remove suspended solids and sediments in the wastewater. Solid-liquid separation is a key step in removing large particles in the wastewater, providing a cleaner fluid for membrane treatment and reducing membrane pollution and clogging. Its advantages are that it improves treatment efficiency, extends the service life of the membrane, and reduces operating costs.

[0118] As mentioned above, the first membrane treatment device 33, including a multi-media filter 331, an ultrafiltration device 332 and a special membrane separation device 333, is used to further purify the alkalized wastewater and remove finer suspended matter, certain dissolved matter and microorganisms. The first membrane treatment device 33 deeply purifies the wastewater through a multi-stage membrane system, effectively removes impurities of various sizes, and provides a high-quality filtration effect. Its advantage is that the treated water quality is purer and suitable for discharge or use in other industrial processes. At the same time, multi-stage filtration can select the most effective membrane technology for different pollutants.

[0119] As mentioned above, the multi-media filter 331, the ultrafiltration device 332 and the special membrane separation device 333 in the first membrane treatment device 33 are key components, which play an important role in the lithium iron phosphate wastewater treatment system 100, ensuring the deep purification of the wastewater and improving the treatment efficiency.

[0120] Among them, the multi-media filter 331 is usually composed of a variety of filter media (such as sand, quartz, activated carbon, etc.), which is used to remove suspended matter, particulate matter, particulate matter and organic matter in water. It removes these impurities by physical interception and adsorption. It is mainly used to remove large particles of suspended matter and reduce the pollution burden of subsequent membrane treatment units. Its advantages are that it improves the efficiency of the subsequent treatment stage, prevents early clogging of membrane treatment equipment, and reduces chemical demand and subsequent maintenance costs.

[0121] Among them, ultrafiltration equipment 332 is a membrane separation technology. The pore size of the semi-permeable membrane used is generally between 0.01 and 0.1 microns, which can effectively remove bacteria, viruses, suspended particles and macromolecular organic matter. It is mainly used to remove macromolecular organic matter, suspended solids and microorganisms in wastewater, and provide a cleaner water source for subsequent nanofiltration or reverse osmosis processes. Its advantage is that it effectively reduces biological and chemical oxygen demand (BOD and COD), provides conditions for subsequent more sophisticated treatment, and improves the stability and reliability of the entire treatment system.

[0122] Special membrane separation equipment 333 refers to a membrane system designed for specific pollutants, such as nanofiltration (NF) or reverse osmosis (RO) membranes made of special materials, which can selectively separate specific chemicals or ions. In this application, it is a nanofiltration system, which consists of an inlet pump, a high-pressure pump, a circulation pump and an ultra-low desalination nanofiltration membrane assembly. The core component is an ultra-low desalination nanofiltration membrane. The nanofiltration membrane has a sulfate retention rate of less than 40% and an organic component retention rate of more than 90%. It is used to remove heavy metal ions, specific organic compounds in wastewater or adjust the hardness and salinity of water. Its advantage is that it can specifically remove difficult-to-treat pollutants in wastewater, such as heavy metals and complex organic compounds, provide extremely high purification efficiency, and help meet more stringent environmental emission standards.

[0123] As mentioned above, the second combined liquid storage tank 34 collects the second mixed liquid treated by the first membrane treatment device 33, provides buffering and temporary storage for further treatment or discharge, ensures a continuous treatment process, homogenizes the quality of the treated water, and provides operational flexibility for the system, thereby providing system operation flexibility and adjustment time, which helps to stabilize and optimize the treatment process.

[0124] Furthermore, in an embodiment of the present application, the alkalization device 31 includes a second mixing reaction tank 311, and an alkalizing agent output device 312 connected to the second mixing reaction tank 311; the second mixing reaction tank 311 is used to receive the first mixed liquid output by the first combined liquid storage tank 22; the alkalizing agent output device 312 stores sodium hydroxide, which is used to add sodium hydroxide into the second mixing reaction tank 311 to alkalize the first mixed liquid during the mixing process.

[0125] The above definition further describes in detail the specific composition of the alkalization device 31, including the second mixing reaction tank 311 and the alkalizer output device 312, which provides further optimization and precise control for the treatment of lithium iron phosphate wastewater. These settings are aimed at the alkalization treatment stage, and the key is to improve the efficiency and quality of wastewater treatment, especially in the treatment of wastewater containing heavy metals and phosphorus.

[0126] As mentioned above, the second mixing reaction tank 311 is used to receive the first mixed solution from the first combined liquid storage tank 22. In this reaction tank, the first mixed solution is fully mixed with the added alkalizing agent to perform a chemical reaction.

[0127] As mentioned above, the alkalizing agent output device 312 is specifically used to store sodium hydroxide, and can accurately control the amount of sodium hydroxide added to the second mixing reaction tank 311 to ensure the efficiency and effectiveness of the alkalization process.

[0128] The use of the alkalizer output device 312 is mainly to achieve accurate control of the chemical dosage during the alkalization process, which is the key to ensuring the alkalization effect, optimizing subsequent treatment steps (such as solid-liquid separation and membrane treatment) and meeting environmental protection requirements. Accurate alkalizer addition can ensure: complete precipitation of heavy metals in wastewater, avoid excessive alkalizer addition, reduce chemical use costs, and maintain the stability and predictability of the wastewater treatment process.

[0129] In summary, by introducing the precisely controlled alkalizer output device 312, the control accuracy and efficiency of the entire wastewater treatment system are enhanced, which helps to improve the quality and economic benefits of wastewater treatment while ensuring environmental safety and compliance with regulatory emission standards.

[0130] Furthermore, in the embodiment of the present application, the first membrane treatment unit 3 also includes an electrocatalytic and sludge disposal device 35; one end of the electrocatalytic and sludge disposal device 35 is connected to the first membrane treatment device 33 to receive the concentrated liquid output by the first membrane treatment device 33; the other end of the electrocatalytic and sludge disposal device 35 is connected to the second combined liquid storage tank 34; and the phosphate fertilizer recovery device 5 is connected to the electrocatalytic and sludge disposal device 35; the electrocatalytic and sludge disposal equipment 35 is used to perform electrocatalytic and sludge treatment on the concentrated liquid to obtain a third solid residue and a treated liquid, and the treated liquid is input into the second combined liquid storage tank 34; the phosphate fertilizer recovery device 5 is used to recover the third solid residue.

[0131] As mentioned above, the electrocatalytic and sludge disposal equipment 35 is introduced into the first membrane treatment unit 3 of the embodiment of the present application. These added components further optimize the performance of the lithium iron phosphate wastewater treatment system 100, especially in treating high-concentration pollutants and improving resource recovery efficiency. The introduction of this equipment not only enhances the complexity of the wastewater treatment process, but also enhances its environmental protection and sustainability.

[0132] The electrocatalytic and sludge disposal equipment 35 may include an electrocatalytic device and a sludge disposal device.

[0133] Among them, since lithium iron phosphate wastewater may contain high concentrations of organic matter and substances that are difficult to biodegrade, electrocatalysis can effectively accelerate the degradation of these substances and improve the efficiency of the entire treatment system. Electrocatalytic equipment uses electrocatalytic technology, which is a technology that promotes chemical reactions through electrolytic reactions. In the electrocatalytic process, the electrode acts as a catalyst and changes the redox state of the chemical substance through the application of electric current, thereby accelerating the decomposition of pollutants. In wastewater treatment, electrocatalysis can be used to decompose organic pollutants, degrade difficult-to-degrade compounds, and can directly oxidize pollutants through oxidants (such as oxygen) generated by electrolysis.

[0134] Among them, the sludge generated during the wastewater treatment process contains a large amount of phosphorus and other valuable minerals. Through specialized sludge disposal equipment, it is possible to recycle these substances, reduce waste and improve economic benefits. Sludge disposal equipment usually carries out sludge treatment including thickening, stabilization, disinfection and final volume reduction. These processes treat the accumulated sludge through physical, chemical or biological methods, making it easy to handle or use for resource recovery. In the wastewater treatment system, sludge treatment equipment is used to treat and stabilize sludge, reduce its volume, and recover valuable components such as phosphorus.

[0135] By adopting the electrocatalytic and sludge treatment equipment 35, the following advantages can be achieved: (1) Improved treatment efficiency: The electrocatalytic equipment can effectively treat organic pollutants in wastewater and reduce chemical oxygen demand (COD) and biochemical oxygen demand (BOD). The sludge treatment equipment ensures the safe disposal and resource recovery of sludge, especially the recovery of phosphorus, which is a valuable resource and is often used in fertilizer production and other industrial applications. (2) Environmentally friendly: Electrocatalysis does not use additional chemical additives, reducing the possibility of secondary pollution. The sludge treatment equipment reduces the pressure on the environment by reducing the amount of sludge and treating harmful components. (3) Cost-effectiveness: The electrocatalytic process has low energy consumption and can treat wastewater more economically than traditional chemical treatment methods. Sludge treatment reduces disposal costs and raw material purchase costs through resource recovery. In addition, the use of the phosphate fertilizer recovery device 5 is to recover phosphorus from the solid residue generated during the treatment process, which not only contributes to the recycling of resources, but also reduces environmental pollution. By recovering the third solid residue from the electrocatalytic and sludge treatment equipment, useful minerals such as phosphorus can be converted into phosphate fertilizers, providing important input materials for agriculture.

[0136] In summary, by introducing the electrocatalytic and sludge disposal equipment 35, the treatment capacity and resource recovery efficiency of the lithium iron phosphate wastewater treatment system 100 are enhanced, providing an environmentally friendly and economical solution to meet the challenges of high-concentration industrial wastewater.

[0137] For further information, please refer to Figure 4 In the embodiment of the present application, the second membrane treatment unit 4 includes a softener 41 for softening the second mixed liquid, a second membrane treatment device 42 and a clear liquid recovery tank 43 for recovering recoverable clear liquid, which are connected in sequence.

[0138] The above content of this embodiment provides the structure of the second membrane treatment unit 4 in the lithium iron phosphate wastewater treatment system 100, especially the configuration of the softener 41, the second membrane treatment device 42 and the clear liquid recovery tank 43. This configuration is intended to further improve the efficiency of wastewater treatment and the purity of water quality, especially when treating wastewater containing high concentrations of minerals and salts.

[0139] The softener 41, the second membrane treatment device 42 and the clear liquid recovery tank 43 are connected in sequence.

[0140] As mentioned above, the softener 41 is used to reduce the hardness of the water, mainly by removing calcium and magnesium ions from the water. This is usually done through an ion exchange process, using resins or chemical additives (such as lime or sodium hydroxide) to adsorb or precipitate calcium and magnesium ions. The use of the softener 41 can prevent and reduce the formation of scale, improve the efficiency and life of the subsequent membrane treatment system, and prevent membrane clogging and performance degradation caused by excessive hardness.

[0141] It should be noted that in the treatment of lithium iron phosphate wastewater, the softener 41 is used mainly to deal with the high hardness problem in the wastewater. Lithium iron phosphate wastewater may contain high mineral salts such as calcium and magnesium. These components may cause serious scaling problems to the membrane treatment equipment if they are not treated, resulting in reduced efficiency and shortened life of the membrane. By using the softener 41, these hardness components can be effectively removed, thereby protecting the membrane treatment equipment and extending its service life, while ensuring the efficiency and continuity of the treatment process.

[0142] As mentioned above, the second membrane treatment device 42 further filters and purifies the softened wastewater, and the membrane technology used may include but is not limited to reverse osmosis, nanofiltration or ultrafiltration, etc. The second membrane treatment device is used to ensure that the final water quality reaches a higher purity standard and is suitable for discharge or reuse.

[0143] As mentioned above, the clear liquid recovery tank 43 is used to collect the clear liquid treated by the second membrane treatment device 42 for storage or further use, thereby providing a buffer and storage facility for treated water, allowing the treatment system to operate continuously while allowing the treated water to be used on demand.

[0144] As mentioned above, the water collected in the clear liquid recovery tank 43 is pure water and distilled water, which can be reused in production to further reduce production costs.

[0145] By using a softener 41, a second membrane treatment device 42 and a clear liquid recovery tank 43 connected in sequence in the second membrane treatment unit 4, the treatment efficiency and system life can be further improved: the softening treatment can significantly improve the efficiency and life of the subsequent membrane treatment device by removing calcium and magnesium ions that may cause damage to the membrane system; the purpose of improving water quality can be achieved: the second membrane treatment unit 4 can provide a high level of purification effect to ensure that the water quality after wastewater treatment meets strict environmental protection or industrial use standards; sustainability and economy can be further achieved: reducing hardness-related maintenance costs and operation interruptions, and improving the economy and sustainability of the entire treatment system.

[0146] Further, in the embodiment of the present application, the second membrane treatment unit 4 further includes a metal ion treatment device 44;

[0147] The metal ion treatment device 44 includes a precipitant output device 441, a precipitation crystallization tank 442, a separation mechanism 443 and an evaporator 444;

[0148] The second membrane treatment device 42, the precipitation crystallization tank 442, the separation mechanism 443 and the evaporator 444 are connected in sequence;

[0149] The second membrane treatment device 42 is a reverse osmosis device;

[0150] The evaporator 444 is connected to the clear liquid recovery tank 43 so that the distilled water after distillation by the evaporator 444 enters the clear liquid recovery tank 43;

[0151] The precipitant output device 441 is connected to the precipitation crystallization tank 442 and is used to input the precipitant into the precipitation crystallization tank 442 .

[0152] The second membrane treatment unit 4 of the lithium iron phosphate wastewater treatment system 100 is further refined in the embodiment of the present application, in particular, by introducing a metal ion treatment device 44, including a precipitant output device 441, a precipitation crystallization tank 442, a separation mechanism 443 and an evaporator 444. The addition of these components is intended to optimize the treatment system, in particular, for efficient treatment and resource recovery of metal ions in wastewater.

[0153] As mentioned above, the metal ion treatment device 44 includes: a precipitant output device 441, a precipitation crystallization tank 442, a separation mechanism 443 and an evaporator 444. Wherein, the precipitant output device 441: a precipitant such as sodium carbonate, lime or other chemical substances (the precipitant used in the embodiment of the present application is sodium carbonate) is added to the precipitation crystallization tank 442 to precipitate metal ions in the wastewater. Wherein, the precipitation crystallization tank 442: Here, the added precipitant reacts with the metal ions in the water to form a precipitate, which is convenient for subsequent separation and treatment. Wherein, the separation mechanism 443: separates the precipitate and the liquid from the precipitation crystallization tank 442, and the precipitate may be further processed or treated as solid waste, while the clear liquid continues to evaporate or other treatments. Wherein, the evaporator 444: is used to evaporate water from the treated liquid, further purify and recover the remaining solution.

[0154] As mentioned above, the use of the precipitant output device 441 is to ensure that the amount and timing of the precipitant addition can be accurately controlled to optimize the metal ion removal process. Accurately controlling the use of the precipitant not only improves the treatment efficiency, but also helps avoid excessive use of chemicals, thereby reducing treatment costs and potential chemical pollution.

[0155] As mentioned above, the second membrane treatment device 42 is a reverse osmosis device, which is used to further remove dissolved solids and fine suspended particles in water. Reverse osmosis is a process of separating a solvent from a solution under pressure through a semipermeable membrane.

[0156] It should be noted that reverse osmosis equipment applies a pressure higher than the osmotic pressure of the solution to force the solvent (usually water) to transfer from the side with higher concentration to the side with lower concentration through a semipermeable membrane. This process can intercept most dissolved salts, organic matter, microorganisms and other particles in the solution, so it is used in water treatment and purification.

[0157] By adopting the metal ion treatment device 44, the following technical effects are achieved: efficient metal removal, the use of precipitants can effectively remove heavy metal ions in water, which is critical to meeting environmental standards and protecting subsequent treatment equipment such as reverse osmosis membranes; improving water quality, reverse osmosis equipment can greatly reduce the content of dissolved solids, provide high-quality water, suitable for industrial reuse or to meet more stringent emission standards; resource recovery and cost-effectiveness, through precipitation and evaporation processes, certain valuable metals can be recovered, reducing waste treatment costs and creating economic value. In addition, the water recovered in the evaporation process can be recycled, reducing the overall water demand and cost of the treatment system.

[0158] In summary, in the embodiments of the present application, a comprehensive treatment solution for lithium iron phosphate wastewater is provided by combining chemical precipitation, separation, evaporation and advanced membrane treatment technology, which not only improves the treatment efficiency and water quality, but also enhances the system's resource recovery capabilities and environmental sustainability.

[0159] Further, in the embodiment of the present application, the second membrane treatment unit 4 further includes a lithium carbonate recovery device 45 and a sodium sulfate recovery device 46;

[0160] The lithium carbonate recovery device 45 is connected to the separation mechanism 443 to recover the first crystalline material after solid-liquid separation;

[0161] The sodium sulfate recovery device 46 is connected to the evaporator 444 to recover the second crystalline material generated after the evaporator 444 is processed.

[0162] In the embodiment of the present application, the resource recovery capacity of the lithium iron phosphate wastewater treatment system 100 is further enhanced by introducing the lithium carbonate recovery device 45 and the sodium sulfate recovery device 46, which is of great significance for improving the comprehensive utilization efficiency and environmental protection of the wastewater treatment system. These added components are specifically used to recover valuable components in the wastewater, further reducing resource waste and increasing economic returns.

[0163] As mentioned above, the lithium carbonate recovery device 45 is used to recover lithium carbonate from the solid or dissolved material separated during the treatment process. Lithium carbonate can usually be recovered from the lithium-containing solution by chemical precipitation, crystallization or ion exchange process. In this arrangement, heating or chemical treatment may be involved to promote the crystallization and precipitation of lithium carbonate, followed by collection by solid-liquid separation equipment.

[0164] As mentioned above, the sodium sulfate recovery device 46 is used to recover sodium sulfate from the evaporation or crystallization process. When the liquid is processed in the evaporator 444, the sodium sulfate can be separated by concentration and crystallization of the solution during the evaporation process. The crystallized sodium sulfate can then be collected and reused.

[0165] The lithium carbonate recovery unit 45 and the sodium sulfate recovery unit 46 are used for the following purposes: (1) Economic and environmental motivations: lithium carbonate is a key raw material for lithium battery manufacturing and has a high market value. Sodium sulfate, as a common industrial salt, is used in many chemical processes. By recycling these chemicals, companies can reduce the cost of purchasing raw materials while reducing waste generation and related environmental impacts. (2) Technical feasibility: using modern chemical and physical treatment technologies (such as crystallization, precipitation, evaporation, etc.), these compounds can be effectively recovered from wastewater, and it is technically feasible to integrate these technologies into wastewater treatment systems.

[0166] In summary, the lithium carbonate recovery device 45 and the sodium sulfate recovery device 46 added in the above embodiment of the present application significantly improve the resource recovery capacity and economic benefits of the wastewater treatment system, and also embody the principles of environmental protection and sustainable development. This integrated method not only optimizes the wastewater treatment process, but also provides a comprehensive and efficient solution for lithium iron phosphate wastewater treatment.

[0167] Please also read Figures 1 to 4 According to the above embodiments of the present application, the lithium iron phosphate wastewater treatment system 100 provided by the present application is a highly integrated and multi-level wastewater treatment framework as a whole, the purpose of which is to maximize treatment efficiency, optimize resource recovery, and ensure that environmental impact is minimized.

[0168] Capable of achieving efficient pollutant removal and water purification: Through multiple steps including oxidation pretreatment unit 2, membrane treatment unit and electrocatalytic facilities, the system can effectively remove organic matter, inorganic salts, heavy metals and other suspended matter, significantly improving the effluent quality, making it suitable for reuse or safe discharge.

[0169] Ability to achieve resource recovery and reuse: Through the phosphate fertilizer recovery unit 5, the lithium carbonate recovery unit 45 and the sodium sulfate recovery unit 46, the system not only treats wastewater but also recovers valuable chemicals in the wastewater, such as phosphorus, lithium and sodium, which are important in many industrial processes.

[0170] It can achieve both economic and environmental benefits: it reduces the cost of wastewater treatment and waste disposal, while reducing the demand for raw materials and lowering the environmental footprint through recycling and reuse.

[0171] By adopting the lithium iron phosphate wastewater treatment system 100 provided in this application, the following advantages can be achieved: (1) Integration: Each unit in the design is closely linked to form a closed-loop treatment process, from preliminary physical treatment to chemical treatment, and then to advanced membrane treatment technology. Each step provides more optimized treatment conditions for the next step. (2) Technological innovation and wide application: The use of advanced technologies such as electrocatalysis and special membrane technology improves the treatment efficiency and adaptability of the system, and can treat different types of industrial wastewater, especially wastewater containing heavy metals and organic compounds. (3) Economic and environmental benefits: The design of the system takes into account operating costs and environmental impacts, and achieves a win-win situation of economic and environmental benefits by reducing the use of chemicals and increasing the recovery of valuable substances.

[0172] In summary, the entire lithium iron phosphate wastewater treatment system 100 shows an overall wastewater treatment structure and a multi-stage treatment process based on the structure, which combines physical, chemical and biological treatment technologies, not only improving the efficiency and effect of wastewater treatment, but also realizing resource recovery and reuse. The design concept of this system reflects the development trend of modern wastewater treatment technology towards a more efficient, economical and environmentally friendly direction.

[0173] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A lithium iron phosphate wastewater treatment system, characterized in that: It includes a phosphate fertilizer recovery device, and a wastewater storage tank, an oxidation pretreatment unit, a first membrane treatment unit and a second membrane treatment unit which are connected in sequence; The phosphate fertilizer recovery device is connected to both the oxidation pretreatment unit and the first membrane treatment unit; The oxidation pretreatment unit is used to perform oxidation treatment on the wastewater input into the wastewater storage tank, thereby obtaining an oxidized first mixed liquid and a first solid residue; The first membrane treatment unit is used to treat the first mixed liquid by membrane separation technology to obtain a second mixed liquid and a second solid residue; The second membrane treatment unit is used to purify the second mixed liquid to obtain a recoverable clear liquid; The phosphate fertilizer recovery device is used to recover the first solid residue and the second solid residue as phosphate fertilizer.

2. The lithium iron phosphate wastewater treatment system according to claim 1, characterized in that: The oxidation pretreatment unit comprises: a centrifuge, a first combined liquid storage tank and an oxidation treatment device; The centrifuge is connected to the wastewater storage tank and is used to perform centrifugal separation treatment on the wastewater input into the wastewater storage tank; The first combined liquid storage tank is connected to the centrifuge; and the oxidation treatment device is connected to the centrifuge at one end and to the first combined liquid storage tank at the other end; The first combined liquid storage tank is used to receive the remaining liquid portion after centrifugation by the centrifuge; The oxidation treatment device is used to receive the remaining solid residue after centrifugation of the centrifuge, and to obtain the first solid residue and oxidized liquid after oxidation treatment of the solid residue, and to input the oxidized liquid into the first combined liquid storage tank to mix with the remaining liquid after centrifugation to obtain the first mixed liquid.

3. The lithium iron phosphate wastewater treatment system according to claim 2, characterized in that: The oxidation treatment device comprises a first mixing reaction tank, an oxidant supplement tank assembly and a filtering mechanism; One end of the first mixing reaction tank is connected to the centrifuge, and the other end is connected to the filtering mechanism; The oxidant replenishing tank assembly is connected to the first mixing reaction tank and is used to input the oxidant into the first mixing reaction tank so that the materials in the first mixing reaction tank undergo oxidation reaction during the mixing process; The filtering mechanism is used to receive the reaction material output from the first mixing reaction tank, and can filter the reaction material to obtain the first solid residue and the oxidized liquid; The phosphate fertilizer recovery device is connected to the filtering mechanism to recover the first solid residue generated by the filtering mechanism.

4. The lithium iron phosphate wastewater treatment system according to claim 3, characterized in that: The oxidant supplement tank assembly includes a sulfuric acid output device for outputting sulfuric acid to the first mixing reaction tank and a hydrogen peroxide output device for outputting hydrogen peroxide.

5. The lithium iron phosphate wastewater treatment system according to claim 2, characterized in that: The first membrane treatment unit comprises an alkalization device, a solid-liquid separation device, a first membrane treatment device, and a second combined liquid storage tank connected in sequence; The alkalization device is connected to the first combined liquid storage tank, and is used to receive the first mixed liquid output from the first combined liquid storage tank, and perform alkalization treatment on the first mixed liquid; The solid-liquid separation device is used to perform solid-liquid separation on the first mixed liquid after alkalization treatment to obtain a second solid residue and an alkalized liquid; The first membrane treatment device comprises a multi-media filter, an ultrafiltration device and a special membrane separation device connected in sequence, for filtering the alkalized liquid to obtain the second mixed liquid, and outputting the second mixed liquid to the second combined liquid storage tank; The phosphate fertilizer recovery device is connected to the solid-liquid separation device to recover the second solid residue.

6. The lithium iron phosphate wastewater treatment system according to claim 5, characterized in that: The alkalization device comprises a second mixing reaction tank and an alkalizing agent output device connected to the second mixing reaction tank; The second mixing reaction tank is used to receive the first mixed liquid output from the first combined liquid storage tank; The alkalizing agent output device stores sodium hydroxide, which is used to input sodium hydroxide into the second mixing reaction tank to alkalize the first mixed solution during the mixing process.

7. The lithium iron phosphate wastewater treatment system according to claim 5, characterized in that: The first membrane treatment unit also includes electrocatalysis and sludge disposal equipment; One end of the electrocatalytic and sludge treatment device is connected to the first membrane treatment device to receive the concentrated liquid output by the first membrane treatment device; The other end of the electrocatalytic and sludge disposal equipment is connected to the second combined liquid storage tank; Furthermore, the phosphate fertilizer recovery device is connected to the electrocatalytic and sludge disposal equipment; The electrocatalytic and sludge treatment equipment is used to perform electrocatalytic and sludge treatment on the concentrated liquid to obtain a third solid residue and a treated liquid, and the treated liquid is input into the second combined liquid storage tank; The phosphate fertilizer recovery device is used to recover the third solid residue.

8. The lithium iron phosphate wastewater treatment system according to claim 5, characterized in that: The second membrane treatment unit includes a softener for softening the second mixed liquid, a second membrane treatment device and a clear liquid recovery tank for recovering recoverable clear liquid, which are connected in sequence.

9. The lithium iron phosphate wastewater treatment system according to claim 8, characterized in that: The second membrane treatment unit also includes a metal ion treatment device; The metal ion treatment device comprises a precipitant output device, a precipitation crystallization tank, a separation mechanism and an evaporator; The second membrane treatment device, the precipitation crystallization tank, the separation mechanism and the evaporator are connected in sequence; The second membrane treatment device is a reverse osmosis device; The evaporator is connected to the clear liquid recovery tank so that the distilled water after distillation by the evaporator enters the clear liquid recovery tank; The precipitant output device is connected to the precipitation crystallization tank and is used for inputting the precipitant into the precipitation crystallization tank.

10. The lithium iron phosphate wastewater treatment system according to claim 9, characterized in that: The second membrane treatment unit also includes a lithium carbonate recovery device and a sodium sulfate recovery device; The lithium carbonate recovery device is connected to the separation mechanism to recover the first crystalline material after solid-liquid separation; The sodium sulfate recovery device is connected to the evaporator to recover the second crystalline material generated after the evaporator is treated.

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