Lithium recovery system for lithium iron phosphate production wastewater

Abstract

The utility model provides a lithium recovery system for lithium iron phosphate production wastewater, which is characterized by comprising an aeration carbon removal tank, a reaction tank, a sedimentation tank, an ultrafiltration device, an ultrafiltration water production tank, a nanofiltration device, a nanofiltration water production tank, a reverse osmosis system and a lithium salt recovery tank which are sequentially connected. According to the utility model, the waste liquid can be converted into the solid material, and the reduction and recycling process of the lithium iron phosphate production wastewater is greatly promoted. The lithium iron phosphate production wastewater treatment device not only can treat lithium iron phosphate production wastewater, but also can effectively recover the lithium element in the wastewater, thereby providing powerful technical support for sustainable development of the new energy industry.

Description

Technical Field

[0001] The utility model relates to a lithium recovery system, more specifically, to a lithium recovery system for lithium iron phosphate production wastewater. Background Art

[0002] With the growing global awareness of the depletion of traditional oil resources and their environmental impact, governments worldwide are increasingly focusing on sustainable energy solutions. Against this backdrop, market demand for new energy vehicles, driven by their unique advantages of being green, environmentally friendly, and pollution-free, continues to rise, directly driving the rapid development of power battery technology. Lithium iron phosphate batteries, with their exceptional safety, relatively low cost, and excellent cycle performance, have secured a prominent position in the power vehicle and energy storage markets, demonstrating broad application prospects.

[0003] However, the wastewater generated during the production of lithium iron phosphate battery materials cannot be ignored. This wastewater is rich in valuable resources such as lithium, iron, and phosphorus. If discharged directly without effective treatment, it will not only seriously pollute the natural environment but also lead to a huge waste of resources. With the growing popularity of green economy and circular development concepts, the efficient and environmentally friendly utilization of the resources in this wastewater has become a focus of attention both within the industry and beyond. In particular, lithium, a key raw material in the new energy sector, its recycling and reuse not only aligns with sustainable development strategies but also effectively alleviates resource shortages. While there is considerable research on technologies for recovering lithium from spent lithium batteries, there is a lack of literature on resource recovery from lithium iron phosphate production wastewater, particularly on lithium recovery technologies. This situation has prompted both industry and academia to focus more on lithium recovery strategies during the production phase, aiming to maximize resource utilization and minimize environmental impact at the source. Therefore, the development of innovative technologies for efficient and economical lithium iron phosphate production wastewater treatment and lithium recovery processes is becoming a research hotspot and future development direction in the field of new energy materials. This not only requires interdisciplinary knowledge integration and technological innovation, but also the joint efforts of the government, enterprises, scientific research institutions and all sectors of society to jointly promote the green and circular upgrading of the new energy vehicle industry chain.

[0004] In light of this, this utility model aims to develop a lithium recovery system for lithium iron phosphate production wastewater. This system converts wastewater into solid materials, significantly promoting the reduction and resource utilization of lithium iron phosphate production wastewater. This utility model not only treats lithium iron phosphate production wastewater but also effectively recovers the lithium element from the wastewater, providing strong technical support for the sustainable development of the new energy industry. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a lithium recovery system for lithium iron phosphate production wastewater, which adopts the following technical solutions:

[0006] A lithium recovery system for lithium iron phosphate production wastewater, characterized by:

[0007] Includes sequential connections:

[0008] an aeration and carbon removal tank, used to remove carbonate ions in the wastewater to obtain a first mixed liquid;

[0009] a reaction tank, for adjusting the pH of the first mixed solution and precipitating a precipitate to obtain a first solid-liquid mixture;

[0010] a sedimentation tank, for performing solid-liquid separation on the first solid-liquid mixture to obtain a first filtrate and precipitated solids;

[0011] An ultrafiltration device, used for treating the first filtrate to obtain a first concentrated water and a first produced water;

[0012] Ultrafiltration water production tank, used to regulate the first produced water;

[0013] A nanofiltration device for treating the first produced water to obtain a second concentrated water and a second produced water;

[0014] Nanofiltration water production pool, used to regulate the second produced water;

[0015] Reverse osmosis concentration system, used to treat the second produced water and obtain third concentrated water and third produced water;

[0016] Lithium salt recovery pool, used to treat the third concentrated water and recover lithium salt;

[0017] Furthermore, the ultrafiltration device, nanofiltration device and reverse osmosis concentration system all use spiral membrane components;

[0018] Furthermore, it also includes a first feeding device for adding an acidic destabilizing agent, a first aeration device for adding gas, a second feeding device for adding an alkaline regulator, a third feeding device for adding an acidic regulator, and a fourth feeding device for adding a carbonate;

[0019] Furthermore, the heating device in the lithium salt recovery tank adopts any one of steam heating and electromagnetic heating equipment.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] (1) The system has a streamlined and efficient process: the overall design pursues extreme simplicity, and the operation process is intuitive and easy to understand, which greatly improves the convenience of operation;

[0022] (2) The system deeply purifies pollutants and produces high-quality lithium salts: After careful acid-base adjustment, the concentration of pollutants in the effluent is significantly reduced, and the purity of the resulting lithium salt product reaches industry-leading levels;

[0023] (3) The system has a compact process and minimizes lithium loss: by optimizing the process layout, the production path is shortened, effectively reducing the loss of lithium elements in the process, ensuring the high efficiency and stability of the overall recovery rate;

[0024] (4) The system turns wastewater into treasure and significantly improves economic benefits: it innovatively realizes the efficient recovery and preparation of lithium carbonate from wastewater, which not only solves the problem of wastewater treatment, but also significantly improves the economic benefits of resource recycling, achieving a win-win situation of environmental friendliness and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural diagram of the present utility model.

[0026] Among them, 1-aeration and carbon removal tank, 2-reaction tank, 3-sedimentation tank, 4-ultrafiltration device, 5-ultrafiltration water production tank, 6-nanofiltration device, 7-nanofiltration water production tank, 8-reverse osmosis system, 9-lithium salt recovery tank, 10-aeration equipment, 11-first acid addition equipment, 12-alkali addition equipment, 13-second acid addition equipment, 14-carbonate addition equipment, 15-heating equipment. DETAILED DESCRIPTION

[0027] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific implementations.

[0028] like Figure 1 As shown, the utility model provides a lithium recovery system for lithium iron phosphate production wastewater, which includes an aeration and carbon removal tank 1, a reaction tank 2, a sedimentation tank 3, an ultrafiltration device 4, an ultrafiltration water production tank 5, a nanofiltration device 6, a nanofiltration water production tank 7, a reverse osmosis system 8, a lithium salt recovery tank 9, an aeration device 10, a first acid adding device 11, an alkali adding device 12, a second acid adding device 13, a carbonate adding device 14, and a heating device 15.

[0029] The system comprises, connected in sequence:

[0030] Aeration and carbon removal tank 1, used to remove carbonate ions in wastewater to obtain a first mixed liquid;

[0031] Reaction tank 2, used to adjust the pH of the first mixed solution and precipitate to obtain a first solid-liquid mixture;

[0032] a sedimentation tank 3, for performing solid-liquid separation on the first solid-liquid mixture to obtain a first filtrate and first filtrate solids;

[0033] Ultrafiltration device 4, used for treating the first filtrate to obtain first concentrated water and first product water;

[0034] Ultrafiltration water production pool 5, used to regulate the first produced water;

[0035] Nanofiltration device 6, used for treating the first produced water to obtain second concentrated water and second produced water;

[0036] Nanofiltration water production pool 7, used to regulate the second produced water;

[0037] The reverse osmosis system 8 is used to process the second produced water and obtain the third concentrated water and the third produced water.

[0038] The lithium salt recovery tank 9 is used to process the third concentrated water and recover lithium salt.

[0039] The ultrafiltration device 4, nanofiltration device 6 and reverse osmosis system 8 all use spiral membrane components.

[0040] It also includes a first acid adding device 11 for adding an acidic destabilizing agent, an aeration device 10 for adding gas, an alkali adding device 12 for adding an alkaline regulator, a second acid adding device 13 for adding an acidic regulator, and a carbonate adding device 14 for adding carbonate.

[0041] The lithium salt recovery tank 9 is provided with a heating device 15 , and the heating device 15 is any one of steam heating and electromagnetic heating.

[0042] The system's processing flow is as follows:

[0043] The lithium iron phosphate production wastewater enters the aeration and carbon removal tank 1, the first acid adding device 11 adjusts the pH value of the water sample to below 3, and the air is blown into the aeration device 10 for carbon removal reaction, and the reaction time is 60 minutes; the effluent from the aeration and carbon removal tank 1 enters the reaction tank, and the alkali adding device adds lime to adjust the pH value of the water sample to 7~8, and reacts under this pH value condition for 30 minutes to 60 minutes to obtain a solid-liquid mixed slurry; the solid-liquid mixed slurry enters the sedimentation tank 3 from the reaction tank 2 and is allowed to stand, and the first filtrate solid and the first filtrate are obtained after solid-liquid separation; the first filtrate is filtered by the ultrafiltration device 4 and enters the ultrafiltration water production tank 5. Before entering the nanofiltration device 6, the second acid adding device 13 must be used to adjust the pH value of the water sample to weak acidity; the water sample after pH adjustment enters the nanofiltration device 6 for separation treatment, and the lithium ions in the filtrate are separated from other divalent and trivalent ions, so that the lithium ions enter the fresh water, while other divalent and above ions enter the fresh water. Impurity ions, such as residual phosphate and iron ions, are retained in the concentrated water; the water produced by the nanofiltration device 6 enters the nanofiltration water production pool 7, and is then concentrated through the reverse osmosis system 8. The obtained reverse osmosis water can be reused in the front-end workshop, and the concentrated water enters the lithium salt recovery pool 9 for reaction; the molar ratio of carbonate ions introduced by the carbonate addition device 14 to lithium ions in the concentrated water should be 1.1~2.0:2, the reaction pH value is 9~10, the reaction temperature is controlled at 80~90℃ by the heating device 15, the stirring speed is 500 r / min, the reaction time is 60 min, and the recovered lithium carbonate enters the subsequent treatment. Example

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0045] like Figure 1 As shown, this project adopts the above technical solution to trial-produce a lithium recovery system for lithium iron phosphate production wastewater, and the treatment object is.

[0046] The system comprises, connected in sequence:

[0047] Aeration and carbon removal tank 1, used to remove carbonate ions in wastewater to obtain a first mixed liquid;

[0048] Reaction tank 2, used to adjust the pH of the first mixed solution and precipitate to obtain a first solid-liquid mixture;

[0049] a sedimentation tank 3, for performing solid-liquid separation on the first solid-liquid mixture to obtain a first filtrate and first filtrate solids;

[0050] Ultrafiltration device 4, used for treating the first filtrate to obtain first concentrated water and first product water;

[0051] Ultrafiltration water production pool 5, used to regulate the first produced water;

[0052] Nanofiltration device 6, used for treating the first produced water to obtain second concentrated water and second produced water;

[0053] Nanofiltration water production pool 7, used to regulate the second produced water;

[0054] a reverse osmosis system 8, for treating the second produced water to obtain third concentrated water and third produced water;

[0055] The lithium salt recovery tank 9 is used to process the third concentrated water and recover lithium salt.

[0056] The ultrafiltration device 4, nanofiltration device 6 and reverse osmosis system 8 all use spiral membrane components.

[0057] It also includes a first acid adding device 11 for adding an acidic destabilizing agent, an aeration device 10 for adding gas, an alkali adding device 12 for adding an alkaline regulator, a second acid adding device 13 for adding an acidic regulator, and a carbonate adding device 14 for adding carbonate.

[0058] The lithium salt recovery tank 9 is provided with a heating device 15 , and the heating device 15 is any one of steam heating and electromagnetic heating.

[0059] This process is used to treat production wastewater from a lithium iron phosphate project. This wastewater has high concentrations of pollutants such as Li, Fe, Ca, Mg, and total phosphorus, posing a significant recovery risk. After treatment using this process, the total phosphorus concentration in the ultrafiltration product water can be reduced to less than 0.5 mg / L, and the total iron concentration to less than 0.1 mg / L. The content of metallic impurities such as Ca and Mg in the nanofiltration product water is also reduced to less than 5 mg / L. After treatment in a reverse osmosis unit, the overall system lithium recovery rate exceeds 95%.

[0060] The above-described embodiments are merely intended to illustrate one embodiment of the present invention and are not intended to limit the present invention. It should be noted that a person skilled in the art may modify the technical solutions described in the above-described embodiments or replace some or all of the technical features therein with equivalents; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of protection of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative work shall fall within the scope of protection of the present invention.

Claims

1. A lithium recovery system for lithium iron phosphate production wastewater, characterized by: Includes sequential connections: an aeration and carbon removal tank, used to remove carbonate ions in the wastewater to obtain a first mixed liquid; a reaction tank, for adjusting the pH of the first mixed solution and precipitating a precipitate to obtain a first solid-liquid mixture; a sedimentation tank, for performing solid-liquid separation on the first solid-liquid mixture to obtain a first filtrate and first filtrate solids; An ultrafiltration device, used for treating the first filtrate to obtain a first concentrated water and a first produced water; Ultrafiltration water production tank, used to regulate the first produced water; A nanofiltration device for treating the first produced water to obtain a second concentrated water and a second produced water; Nanofiltration water production pool, used to regulate the second produced water; Reverse osmosis system, used to treat the secondary produced water and obtain tertiary concentrated water and tertiary produced water; The lithium salt recovery pool is used to treat the third concentrated water and recover lithium salts.

2. The lithium recovery system for lithium iron phosphate production wastewater according to claim 1, characterized in that: The ultrafiltration device, nanofiltration device and reverse osmosis system all adopt rolled membrane components.

3. The lithium recovery system for lithium iron phosphate production wastewater according to claim 1, characterized in that: It also includes a first acid adding device for adding an acidic destabilizing agent, an aeration device for adding gas, an alkali adding device for adding an alkaline regulator, a second acid adding device for adding an acidic regulator, and a carbonate adding device for adding carbonate.

4. The lithium recovery system for lithium iron phosphate production wastewater according to claim 1, characterized in that: The lithium salt recovery pool is provided with a heating device, and the heating device adopts any one of steam heating and electromagnetic heating equipment.

Images