WO2025065232A1 - 一种废旧磷酸铁锂的回收利用方法 - Google Patents

一种废旧磷酸铁锂的回收利用方法 Download PDF

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Publication number
WO2025065232A1
WO2025065232A1 PCT/CN2023/121522 CN2023121522W WO2025065232A1 WO 2025065232 A1 WO2025065232 A1 WO 2025065232A1 CN 2023121522 W CN2023121522 W CN 2023121522W WO 2025065232 A1 WO2025065232 A1 WO 2025065232A1
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Prior art keywords
iron phosphate
filtrate
waste lithium
lithium iron
lithium
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PCT/CN2023/121522
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English (en)
French (fr)
Inventor
唐雪姣
阮丁山
李长东
陈若葵
段金亮
夏阳
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Hunan Brunp Recycling Technology Co Ltd
Guangdong Brunp Recycling Technology Co Ltd
Original Assignee
Hunan Brunp Recycling Technology Co Ltd
Guangdong Brunp Recycling Technology Co Ltd
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Application filed by Hunan Brunp Recycling Technology Co Ltd, Guangdong Brunp Recycling Technology Co Ltd filed Critical Hunan Brunp Recycling Technology Co Ltd
Priority to CN202380011199.5A priority Critical patent/CN117580805B/zh
Priority to PCT/CN2023/121522 priority patent/WO2025065232A1/zh
Publication of WO2025065232A1 publication Critical patent/WO2025065232A1/zh
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/30—Alkali metal phosphates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/37—Phosphates of heavy metals
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D15/00—Lithium compounds
    • C01D15/08—Carbonates; Bicarbonates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/54—Reclaiming serviceable parts of waste accumulators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/84—Recycling of batteries or fuel cells

Definitions

  • the present invention relates to the field of material recycling technology, and in particular to a method for recycling waste lithium iron phosphate.
  • Lithium iron phosphate lithium battery is a kind of power battery with high electrochemical properties and high safety.
  • the common method for recycling waste lithium iron phosphate is wet recycling, that is, all the metal ions (mainly lithium ions) in lithium iron phosphate are leached out, and then the valuable metal ions are selectively recovered by impurity removal and step-by-step precipitation.
  • the recovery rate of traditional wet recycling is low. The main reason is that some metal ions are not recovered in the waste residue or leachate obtained by precipitation during the treatment process.
  • the purpose of this article is to overcome the shortcomings of the above-mentioned prior art and provide a method for recycling waste lithium iron phosphate.
  • the method separately and specifically re-treats the precipitate and leachate obtained by separating and leaching the waste lithium iron phosphate powder, and uses membrane concentration to highly enrich the lithium ions in the leachate and fully utilizes the filtrate generated during the treatment process, so that lithium salts and iron phosphate products can be efficiently recovered and obtained at the same time.
  • a method for recycling waste lithium iron phosphate comprises the following steps:
  • the leachate is adjusted to pH 8-9, impurities are precipitated and filtered to obtain a primary filtrate and a primary filter residue;
  • the primary filtrate is concentrated by a membrane system, and then a precipitant is added to precipitate to obtain lithium salt and a secondary filtrate;
  • the leached residue is reacted with an acid solution under an inert atmosphere, and then a reducing agent and an additive are added to react and filtered, and the resulting mixed solution is added with a second oxidant to react and filtered to obtain iron phosphate and a third filtrate;
  • the reducing agent is elemental iron
  • the additive is ferrous phosphate dihydrate, ferrous phosphate octahydrate, phosphate monohydrate, and ferrous phosphate octahydrate.
  • At least one of titanium hydrogenate, aluminum hydroxide, titanium dioxide, and titanium trioxide; the mass ratio of the leached residue, the reducing agent, and the additive is 100: (20-65): (50-200);
  • the secondary filtrate and the tertiary filtrate are mixed and the pH is adjusted to 9-10, filtered, and then the pH is adjusted to 4-6 and filtered again; the obtained filtrate is treated by fine filtration, ultrafiltration and reverse osmosis to obtain purified water and a concentrate with a pH of 2-4, the concentrate is placed in a primary filter residue and leached, filtered, and a fourth filtrate is obtained, which is treated according to the primary filtrate treatment steps.
  • waste lithium iron phosphate is selectively extracted with an oxidant and an acid solution to obtain a leaching solution containing lithium ions and a leaching residue containing iron, phosphorus and other substances of the electrode such as graphite.
  • the pH of the leaching solution is first adjusted so that some impurity ions, such as iron and aluminum ions, are precipitated in the form of hydroxides or oxides.
  • the obtained primary filtrate is concentrated by a membrane concentration process.
  • this process can prevent the crystallization of lithium salts in the filtrate, and at the same time can further improve the purity of the obtained concentrated solution and reduce energy consumption; after concentration, a precipitant is added to obtain a high-purity lithium salt.
  • iron powder is added to the leaching residue containing iron and phosphorus elements as a reducing agent, and a specific type of additive is introduced.
  • the two substances can react synergistically, induce the precipitation of impurities such as titanium in the filter residue and reduce the loss of iron elements, and efficiently remove impurities.
  • the product after impurity removal can be oxidized to obtain a high-purity iron phosphate.
  • the technical solution described in this article also recovers the secondary filtrate and the tertiary filtrate generated in the above process and converts them into a concentrate.
  • the concentrate is in a liquid state and mainly contains lithium ions that have not been recovered in the previous process.
  • this concentrate is acidic and can be used for leaching of the primary filter residue, so that the lithium ions in the filter residue and the lithium ions in the concentrate are both enriched in the filtrate obtained by leaching. Further membrane concentration and other process treatments are carried out according to the treatment steps of the primary filtrate to achieve lithium ion recovery of the overall recyclate.
  • the first oxidant is at least one of oxygen, hydrogen peroxide, and sodium persulfate.
  • the acid solution is an aqueous solution of at least one of sulfuric acid and hydrochloric acid.
  • the pH of the solution of the leachate after pH adjustment is 8.5.
  • the leaching solution can fully precipitate impurities such as ferric ions, ferrous ions, and aluminum ions, while not causing partial lithium ion precipitation and ultimate lithium loss due to excessively high pH.
  • the membrane system includes a nanofiltration membrane system and a reverse osmosis membrane system in sequence.
  • the membrane system described in this paper first uses a nanofiltration membrane system to separate metal impurities such as calcium, magnesium, and aluminum in the primary filtrate, and then uses a reverse osmosis membrane system to separate lithium in the solution. Ions are enriched.
  • the rate at which the primary filtrate enters the membrane concentration system is 380-420 L/h, the pH is 2-4, and the pressure is 1-1.5 MPa.
  • the lithium ion concentration in the solution is 20 to 25 g/L.
  • the precipitant is at least one of sodium carbonate and sodium phosphate dodecahydrate, the temperature during the precipitation is 80-100° C., and the time is 2-4 hours.
  • the leaching residue reacts with the reducing agent and the additive for 3 to 6 hours.
  • the reaction is carried out for 3 to 6 hours, and the impurity removal rate of the leached slag described in this article can reach more than 90%, so the prepared regenerated iron phosphate has a high purity.
  • the second oxidant is one of oxygen and hydrogen peroxide.
  • the second oxidant is hydrogen peroxide
  • the addition rate of the hydrogen peroxide is 0.7-1.1 mL/min.
  • the introduction of hydrogen peroxide will not cause the growth rate of the precipitated grains to be too fast or too slow, and the iron phosphate finally obtained has a good crystal form and morphology.
  • the second oxidant is oxygen
  • the pressure of the introduced oxygen is 1.2-1.5 MPa.
  • the temperature of the mixed solution when reacting with the second oxidant is ⁇ 80°C.
  • the grain nucleation rate can be effectively controlled within a lower range, thereby maintaining the particle size of the prepared ferric phosphate at a more appropriate size.
  • the unit dosage of the concentrate for leaching the filter residue once is 3-7 mL/g.
  • the concentration of iron in the concentrate is less than 0.001 g/L
  • the concentration of phosphorus is less than 0.001 g/L
  • the concentration of copper is less than 0.0001 g/L
  • the concentration of aluminum is less than 0.0001 g/L
  • the concentration of lithium is 4-5 g/L.
  • the secondary filtrate and the tertiary filtrate are mixed and the pH value is adjusted to 9-10, filtered, and then the pH value is adjusted to 4-6 and filtered again; the obtained filtrate is sequentially filtered through a microporous filter, a plate heat exchanger, and an ultrafiltration device to complete fine filtration and ultrafiltration treatment, and then placed in an ultrafiltration water production tank; the water in the ultrafiltration water production tank is subjected to primary reverse osmosis treatment, secondary reverse osmosis treatment, and tertiary reverse osmosis treatment to obtain purified water, and the osmotic residual liquid phase after the primary reverse osmosis treatment is subjected to reverse osmosis treatment to obtain a concentrate.
  • the concentrate described in this article is used to leach the primary filter residue, which can not only extract the lithium ions contained in the concentrate, but also efficiently leach the lithium ions in the filter residue, ultimately improving the overall lithium recovery rate.
  • This article provides a method for recycling waste lithium iron phosphate.
  • the method specifically re-treats the precipitate and leachate obtained by separating and leaching the waste lithium iron phosphate powder, and uses membrane concentration to highly enrich the lithium ions in the leachate and fully utilizes the filtrate generated during the treatment process.
  • lithium salt and iron phosphate products can be efficiently recovered and obtained at the same time.
  • the overall method can achieve a lithium recovery rate of more than 95% for waste lithium iron phosphate.
  • the concentration of impurity elements in the obtained iron phosphate does not exceed 5ppm, and the quality of the iron phosphate product is relatively high.
  • FIG1 is a schematic flow chart of the method for recycling waste lithium iron phosphate described in this article.
  • the materials used in the examples and comparative examples can be obtained through commercial channels.
  • the pole pieces containing waste lithium iron phosphate used in the embodiments and comparative examples of this article are all positive pole pieces in commercially recycled lithium iron phosphate batteries.
  • the main components are waste lithium iron phosphate, conductive agent and binder. The contents of lithium, phosphorus and iron in the pole pieces were tested before recycling.
  • the membrane concentration system described in this article is composed of a nanofiltration membrane system with a pore size of 1 to 10 nm and a reverse osmosis membrane system with a pore size of 0.4 to 0.6 nm.
  • the rate at which the primary filtrate enters the membrane concentration system is 400 L/h, the pH is 2 to 4, and the pressure is 1 to 1.5 MPa.
  • the lithium ion concentration in the solution is 20 to 25 g/L.
  • the pH of the secondary filtrate and the tertiary filtrate is adjusted to 9-10, filtered, and then the pH is adjusted to 4-6 and filtered again; the resulting filtrate is treated with a reclaimed water system, the reclaimed water system includes a fine filtration-ultrafiltration system and a reverse osmosis system, the fine filtration-ultrafiltration system includes a microporous precision filter, a plate heat exchanger, an ultrafiltration device, and an ultrafiltration water production tank connected to the ultrafiltration device in sequence; the reverse osmosis system includes a primary reverse osmosis device, a secondary reverse osmosis device, a tertiary reverse osmosis device and correspondingly connected water tanks connected in sequence, and the tertiary reverse osmosis device is connected to a terminal reverse osmosis device.
  • the ultrafiltration device After the filtrate flows into the reclaimed water system, it passes through the microporous precision filter and plate heat exchanger of the fine filtration-ultrafiltration system in sequence, and the ultrafiltration device completes the fine filtration and ultrafiltration treatment, and accumulates water in the ultrafiltration water production tank.
  • the water is then treated by the reverse osmosis device of the first-stage reverse osmosis device, the second-stage reverse osmosis device, and the third-stage reverse osmosis device to obtain purified water.
  • the purified water is recycled, and the liquid in the concentrated water tank of the first-stage reverse osmosis device is collected. And through the terminal reverse osmosis device, a concentrate is obtained.
  • An embodiment of the method for recycling waste lithium iron phosphate described herein, as shown in FIG1 comprises the following steps:
  • the leached residue obtained in step (1) is placed in a reactor containing 500 mL of 1 mol/L sulfuric acid solution, and after reacting for 1 hour, the reducing agent elemental iron powder and the additive titanium dioxide are added in stages, mixed, reacted at 50° C. for 3 hours, and the insoluble residue is filtered out to achieve acid dissolution and impurity removal.
  • the resulting mixed solution is transferred to another reactor and 1.2 MPa of oxygen is added to react at 80° C. for 6 hours, filtered, and iron phosphate and three filtrates are obtained; the mass ratio of the leached residue, elemental iron powder and titanium dioxide is 100:31:65;
  • the secondary filtrate and the tertiary filtrate are mixed and adjusted to a pH of 9-10 with sodium hydroxide, and then the pH is adjusted to 4-6 and filtered.
  • the pH of the concentrate obtained after entering the reclaimed water system for treatment is 3.
  • the concentrated water is placed in the primary filter residue and leached.
  • the liquid-to-solid ratio during leaching is 3 mL/g.
  • the concentrate is filtered to obtain a fourth filtrate and a mixed residue that cannot be further extracted with lithium.
  • the fourth filtrate is treated according to the first filtrate treatment steps.
  • the leached residue obtained in step (1) is placed in a reactor containing 500 mL of 1 mol/L sulfuric acid solution, and after reacting for 2 hours, the reducing agent elemental iron powder and additives titanium dioxide and titanium hydrogen phosphate monohydrate are added in stages, mixed, reacted at 80° C. for 5 hours, and the insoluble residue is filtered out to achieve acid dissolution and impurity removal, and the obtained mixed solution is transferred to another reactor and 1.3 MPa of oxygen is added to react at 80° C. for 6 hours, filtered, and iron phosphate and three filtrates are obtained; the mass ratio of the leached residue, elemental iron powder, titanium dioxide and titanium hydrogen phosphate monohydrate is 100:36:80:80;
  • Example 1 The secondary filtrate and the tertiary filtrate are treated in the same manner as in Example 1 to obtain a concentrate, and the concentrate is placed in the primary filter residue and leached, with a liquid-to-solid ratio of 4 mL/g during leaching.
  • the concentrate is filtered to obtain a fourth filtrate and a mixed residue from which lithium cannot be further extracted.
  • the fourth filtrate is treated in the same manner as in Example 1.
  • the leached residue obtained in step (1) is placed in a reactor containing 500 mL of 1 mol/L sulfuric acid solution, and after reacting for 3 hours, the reducing agent elemental iron powder and the additive monohydrogen titanium phosphate are added in stages, mixed, reacted at 50° C. for 6 hours, and the insoluble residue is filtered out to achieve acid dissolution and impurity removal, and the obtained mixed solution is transferred to another reactor and 1.3 MPa of oxygen is added to react at 80° C. for 6 hours, filtered, and iron phosphate and three filtrates are obtained; the mass ratio of the leached residue, elemental iron powder and monohydrogen titanium phosphate is 100:41:100;
  • the secondary filtrate and the tertiary filtrate are treated in the same manner as in Example 1 to obtain a concentrate, and the concentrate is placed in the primary filter residue for leaching, and the liquid-to-solid ratio during leaching is 5 mL/g.
  • the concentrate is filtered to obtain a fourth filtrate and a mixed residue that cannot be further extracted with lithium.
  • the fourth filtrate is treated in the same manner as the primary filtrate treatment steps. Line processing.
  • the leached residue obtained in step (1) is placed in a reactor containing 500 mL of 1 mol/L sulfuric acid solution, and then the reducing agent elemental iron powder and the additive mixture of dihydrated ferric phosphate and titanium oxide are added in stages and mixed, and after reacting for 2 hours, the mixture is reacted at 50° C. for 5 hours and the insoluble residue is filtered out to achieve acid dissolution and impurity removal, and the obtained mixed solution is transferred to another reactor and 1.5 MPa of oxygen is added to react at 80° C. for 6 hours, and filtered to obtain ferric phosphate and three filtrates; the mass ratio of the leached residue, elemental iron powder and the mixture of dihydrated ferric phosphate and titanium oxide is 100:32:85;
  • Example 1 The secondary filtrate and the tertiary filtrate are treated in the same manner as in Example 1 to obtain a concentrate, and the concentrate is placed in the primary filter residue and leached, with a liquid-to-solid ratio of 7 mL/g during leaching.
  • the concentrate is filtered to obtain a fourth filtrate and a mixed residue from which lithium cannot be further extracted.
  • the fourth filtrate is treated in the same manner as in Example 1.
  • step (1) placing the leached residue obtained in step (1) into a reactor containing 500 mL of 1 mol/L sulfuric acid solution, reacting for 2 h, then adding the reducing agent elemental iron powder and the additive ferrous phosphate octahydrate in stages, mixing, reacting at 50° C. for 5 h and filtering out the insoluble residue to achieve acid dissolution and impurity removal, transferring the obtained mixed solution to another reactor and adding 30% hydrogen peroxide at a rate of 0.7 mL/min, reacting at 80° C. for 6 h, filtering, and obtaining iron phosphate and three filtrates; the mass ratio of the leached residue, elemental iron powder and ferrous phosphate octahydrate is 100:52:100;
  • Example 1 The secondary filtrate and the tertiary filtrate are treated in the same manner as in Example 1 to obtain a concentrate, and the concentrate is placed in the primary filter residue and leached, with a liquid-to-solid ratio of 6 mL/g during leaching.
  • the concentrate is filtered to obtain a fourth filtrate and a mixed residue from which lithium cannot be further extracted.
  • the fourth filtrate is treated in the same manner as in Example 1.
  • the leached residue obtained in step (1) is placed in a reactor containing 500 mL of 1 mol/L sulfuric acid solution, and after reacting for 2 h, the reducing agent elemental iron powder and the additive dihydrate ferric phosphate are added in stages, the mixture is reacted at 50° C. for 5 h, and the insoluble residue is filtered out to achieve acid dissolution and impurity removal, the obtained mixed solution is transferred to another reactor and hydrogen peroxide with a concentration of 30% is continuously introduced at a rate of 1.1 mL/min, the reaction is carried out at 80° C. for 6 h, and filtered to obtain ferric phosphate and three filtrates; the mass ratio of the leached residue, elemental iron powder and dihydrate ferric phosphate is 100:40:90;
  • Example 1 The secondary filtrate and the tertiary filtrate are treated in the same manner as in Example 1 to obtain a concentrate, and the concentrate is placed in the primary filter residue and leached, with a liquid-to-solid ratio of 6 mL/g during leaching.
  • the concentrate is filtered to obtain a fourth filtrate and a mixed residue from which lithium cannot be further extracted.
  • the fourth filtrate is treated in the same manner as in Example 1.
  • step (1) placing the leached residue obtained in step (1) into a reactor containing 500 mL of 1 mol/L sulfuric acid solution, reacting for 2 h, then adding the reducing agent elemental iron powder and the additive aluminum hydroxide in stages, mixing, reacting at 50° C. for 5 h and filtering out the insoluble residue to achieve acid dissolution and impurity removal, transferring the obtained mixed solution to another reactor and adding 30% hydrogen peroxide at a rate of 0.8 mL/min, reacting at 80° C. for 6 h, filtering, and obtaining iron phosphate and three filtrates; the mass ratio of the leached residue, elemental iron powder and aluminum hydroxide is 100:62:80;
  • Example 1 The secondary filtrate and the tertiary filtrate are treated in the same manner as in Example 1 to obtain a concentrate, and the concentrate is placed in the primary filter residue and leached, with a liquid-to-solid ratio of 6 mL/g during leaching.
  • the concentrate is filtered to obtain a fourth filtrate and a mixed residue from which lithium cannot be further extracted.
  • the fourth filtrate is treated in the same manner as in Example 1.
  • the leached residue obtained in step (1) was placed in 500 mL of 1 mol/L In a reactor of sulfuric acid solution, after reacting for 1 hour, the reducing agent elemental iron powder and additives titanium trioxide and ferrous phosphate octahydrate are then added in stages, and the mixture is reacted at 50°C for 4 hours and the insoluble residue is filtered out to achieve acid dissolution and impurity removal.
  • the obtained mixed solution is transferred to another reactor and hydrogen peroxide with a concentration of 30% is continuously added at a rate of 1.5 mL/min, and the reaction is carried out at 80°C for 6 hours. After filtering, iron phosphate and three filtrates are obtained; the mass ratio of the leached residue, elemental iron powder, titanium trioxide, and ferrous phosphate octahydrate is 100:62:80:80;
  • Example 1 The secondary filtrate and the tertiary filtrate are treated in the same manner as in Example 1 to obtain a concentrate, and the concentrate is placed in the primary filter residue and leached, with a liquid-to-solid ratio of 6 mL/g during leaching.
  • the concentrate is filtered to obtain a fourth filtrate and a mixed residue from which lithium cannot be further extracted.
  • the fourth filtrate is treated in the same manner as in Example 1.
  • a method for recycling waste lithium iron phosphate the only difference from Example 3 is that the primary filter residue in step (5) is directly leached with pure water, the liquid-to-solid ratio during leaching is 5 mL/g, and filtered to obtain a fourth filtrate and a mixed residue, and the fourth filtrate is treated according to the primary filtrate treatment step.
  • a method for recycling waste lithium iron phosphate the difference from Example 3 is only that the nitrogen atmosphere in step (4) is replaced by air atmosphere.
  • a method for recycling waste lithium iron phosphate the difference from Example 3 is only that no additive is added in step (4).
  • a method for recycling waste lithium iron phosphate which differs from Example 7 only in that the mass ratio of the leached residue, elemental iron powder and aluminum hydroxide is 100:62:300.
  • a method for recycling waste lithium iron phosphate which differs from Example 5 only in that the mass ratio of the leached residue, elemental iron powder and ferrous phosphate octahydrate is 100:52:400.
  • a method for recycling waste lithium iron phosphate which differs from Example 5 only in that the leaching
  • the mass ratio of slag, elemental iron powder and ferrous phosphate octahydrate is 100:52:20.
  • a method for recycling waste lithium iron phosphate which differs from Example 4 only in that the primary filtrate in step (3) is concentrated using a commercially available MVR evaporation system.
  • a method for recycling waste lithium iron phosphate the difference from Example 8 is only that the pH of the solution is 3 after the pH of the leaching solution is adjusted in step (2).
  • a method for recycling waste lithium iron phosphate the only difference from Example 8 is that the pH of the solution after the pH of the leaching solution is adjusted in step (2) is 12.
  • a method for recycling waste lithium iron phosphate the difference from Example 8 is only that the pH of the concentrate in step (5) is 1.
  • a method for recycling waste lithium iron phosphate the difference from Example 8 is only that the pH of the concentrate in step (5) is 6.
  • a method for recycling waste lithium iron phosphate the difference from Example 8 is that the concentrate obtained in step (5) is not subjected to fine filtration or ultrafiltration, and the total concentration of impurity elements other than lithium is 0.08 g/L.
  • the impurity content of the iron phosphate prepared in the method described in each embodiment and comparative example, the iron and phosphorus content of the iron phosphate product and the molar content ratio of the two, and the specific surface area of the iron phosphate product were detected and counted, and finally the lithium recovery rate of the method was counted.
  • the calculation method of the lithium recovery rate is 100-m (lithium in the mixed slag)/m (lithium in the lithium iron phosphate pole piece powder); if there is no reclaimed water reuse system, only pure water is used to wash the lithium-containing mixed slag, and the lithium recovery rate is calculated as follows: 100-m (lithium in mixed slag, lithium in ferrophosphorus slag, lithium in lithium precipitation mother liquor)/m (lithium in lithium iron phosphate electrode powder), and finally the purity of the prepared lithium salt is tested.
  • the lithium recovery rate can reach more than 96%, and the prepared iron phosphate product has high purity, the main impurity concentration does not exceed 5ppm, and the specific surface area is moderate, and the phosphorus-iron ratio corresponds to the standard product.
  • Comparative Example 7 uses a relatively conventional MVR evaporation system to evaporate and concentrate the primary filtrate. Compared with the membrane concentration process, this method is prone to lithium ion loss; Comparative Examples 8 and 9 have too high or too low pH adjustment for the leachate, resulting in too high impurity concentration or too low lithium recovery rate of the prepared lithium salt product.
  • Comparative Examples 10 and 11 since the pH of the concentrate is too high or too low when leaching the primary filter residue, the lithium ion recovery rate of the process is low or the impurity content of the obtained lithium salt is high.
  • Comparative Example 12 the impurity content of the concentrate itself is too high, so the impurity content of the final lithium salt is also high.

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Abstract

一种废旧磷酸铁锂的回收利用方法，属于材料回收技术领域。所述方法对废旧磷酸铁锂粉末分离浸出得到的沉淀和浸出液分别进行特定再处理，并采用膜浓缩对浸出液中的锂离子进行高度富集以及充分利用处理过程中产生的滤液，最终可以同时高效回收并得到锂盐和磷酸铁产品，整体方法对于废旧磷酸铁锂的锂回收率可以达到95％以上，同时得到的磷酸铁中的杂质元素浓度最高不超过5ppm，磷酸铁产品的质量较高。

Description

一种废旧磷酸铁锂的回收利用方法 技术领域
本文涉及材料回收技术领域，尤其涉及一种废旧磷酸铁锂的回收利用方法。
背景技术
磷酸铁锂系锂电池是一种高电化学性、高安全性的动力电池，一般情况下，这种电池中含磷酸铁锂的正极极片在失活报废后存在专门的回收体系进行回收。目前常见的废旧磷酸铁锂回收方法是湿法回收，即将磷酸铁锂中的金属离子(主要为锂离子)全部浸出，随后再采用除杂、分步沉淀的方式对有价金属离子进行选择性回收。然而，传统湿法回收的回收率较低，主要原因在于在处理过程中沉淀所得废渣或者浸出液中还存在部分金属离子没有回收，若要提高这些金属离子的回收率，需要花费较高资金对回收装备例如蒸发浓缩系统进行升级(例如升级为MVR系统)，又或者需要牺牲部分可以回收的产品，无法实现低成本、高效的一体化废旧磷酸铁锂全回收。
发明内容
本文的目的在于克服上述现有技术的不足之处而提供一种废旧磷酸铁锂的回收利用方法，该方法对废旧磷酸铁锂粉末分离浸出得到的沉淀和浸出液分别进行特定再处理，并采用膜浓缩对浸出液中的锂离子进行高度富集以及充分利用处理过程中产生的滤液，最终可以同时高效回收并得到锂盐和磷酸铁产品。
为实现上述目的，本文所采取的技术方案为：
一种废旧磷酸铁锂的回收利用方法，包括以下步骤：
将含废旧磷酸铁锂的极片置入含第一氧化剂的酸溶液中浸出，得浸出液和浸出渣；
将浸出液经pH调节至8～9、沉淀杂质及过滤后，得一次滤液和一次滤渣；
将一次滤液经膜系统浓缩后，加入沉淀剂沉淀，得锂盐和二次滤液；
将浸出渣在惰性气氛下与酸溶液进行反应，随后加入还原剂及添加剂混合反应，过滤，所得混合液加入第二氧化剂进行反应，过滤，得磷酸铁和三次滤液；所述还原剂为单质铁，所述添加剂为二水磷酸铁、八水磷酸亚铁、一水磷 酸氢钛、氢氧化铝、二氧化钛、三氧化二钛中的至少一种；所述浸出渣、还原剂及添加剂的质量之比为100：(20～65)：(50～200)；
将二次滤液和三次滤液混合并调节pH至9～10，过滤，随后调节pH至4～6后并再次过滤；所得滤液经精滤、超滤和反渗透处理后，得纯化水和pH为2～4的浓缩物，所述浓缩物置入一次滤渣并浸出，过滤，得四次滤液，按照一次滤液处理步骤进行处理。
本文所述废旧磷酸铁锂的回收利用方法中，首先通过氧化剂和酸液对废旧磷酸铁锂进行选择性提锂得到含锂离子的浸出液和含有铁、磷元素及极片其他物质诸如石墨等的浸出渣，此时先对浸出液进行溶液pH调节，使得一些杂质离子，例如铁及铝离子以氢氧化物或氧化物的形式沉淀出来，随后所得一次滤液采用膜浓缩工艺进行浓缩，该工艺相比于现有的MVR系统部件能够防止滤液中的锂盐结晶，同时还能进一步提升所得浓缩液的纯度，降低耗能；经过浓缩后加入沉淀剂即可获得高纯度的锂盐。同时，含有铁及磷元素的浸出渣加入铁粉作为还原剂，同时引入特定种类的添加剂，两种物质可以发生协同反应，诱导滤渣中诸如钛等杂质发生沉淀并减少铁元素的损失，高效实现除杂，除杂后的产物经过氧化即可获得纯度较高的磷酸铁。最后，为了实现废旧磷酸铁锂的高锂离子回收率，本文所述技术方案还将上述过程中产生的二次滤液和三次滤液经过回收并转化为浓缩物，该浓缩物成液体状态，其主要含有在先工艺中依然没有回收的锂离子，同时这种浓缩物呈现酸性，因此可以用于一次滤渣的浸出，使得滤渣中的锂离子和浓缩物中的锂离子均富集在浸出所得滤液中，再进一步按照一次滤液的处理步骤进行膜浓缩等工艺处理即可实现整体回收物的锂离子回收。
在一实施例中，所述第一氧化剂为氧气、双氧水、过硫酸钠中的至少一种。
在一实施例中，所述酸溶液为硫酸、盐酸中的至少一种的水溶液。
在一实施例中，所述浸出液经pH调节后的溶液pH为8.5。
在所述pH范围内，浸出液可以充分将铁离子、亚铁离子、铝离子等杂质物质沉淀处理，同时也不会因pH过高而导致部分锂离子析出最终造成锂损失。
在一实施例中，所述膜系统依次包括纳滤膜系统和反渗透膜系统。
本文所述膜系统相比于传统的MVR系统，对于一次滤液先采用纳滤膜系统分离中诸如钙、镁、铝等金属杂质离子，随后采用反渗透膜系统对溶液中的锂 离子进行富集。
进一步地，所述一次滤液进入膜浓缩系统的速率为380～420L/h，pH为2～4，压力为1～1.5MPa。
进一步地，所述一次滤液经膜系统浓缩后溶液中的锂离子浓度为20～25g/L。
在一实施例中，所述沉淀剂为碳酸钠、十二水磷酸钠中的至少一种，所述沉淀时的温度为80～100℃，时间为2～4h。
在一实施例中，所述浸出渣与还原剂及添加剂进行反应的时间为3～6h。
在本文所述配比下的铁单质以及添加剂的协同作用下反应3～6h，本文所述浸出渣的除杂率可以达到90％以上，因此制备的再生磷酸铁纯度较高。
在一实施例中，所述第二氧化剂为氧气、双氧水中的一种。
在一实施例中，所述第二氧化剂为双氧水，所述双氧水的添加速率为0.7～1.1mL/min。
在所述添加速率下，双氧水的引入不会引起沉淀晶粒生长时的速度过快或过慢，最终得到的磷酸铁具有良好的晶型和形貌。
在一实施例中，所述第二氧化剂为氧气，所述通入的氧气的压力为1.2～1.5MPa。
与双氧水类似，在上述通入压力下，制备的磷酸铁的晶型和形貌较佳。
在一实施例中，所述混合液与第二氧化剂反应时的温度≥80℃。
当磷酸铁的生成反应时的温度控制在80℃及以上时，可以有效控制其晶粒成核速率在较低范围，从而制备的磷酸铁粒径维持在较合适的尺寸。
在一实施例中，所述浓缩物浸出一次滤渣时的单位用量为3～7mL/g。
进一步地，所述浓缩物中铁元素的浓度＜0.001g/L，磷元素的浓度＜0.001g/L，铜元素的浓度＜0.0001g/L，铝元素的浓度＜0.0001g/L，锂元素的浓度为4～5g/L。
进一步地，所述二次滤液和三次滤液混合并调节pH至9～10，过滤，随后调节pH至4～6后并再次过滤；所得滤液依次经微孔过滤器、板式换热器，超滤装置完成精滤、超滤处理后，置于超滤产水槽；所述超滤产水槽中的水经过一级反渗透处理、二级反渗透处理和三级反渗透处理后得到纯化水，所述一级反渗透处理后的渗透余留液相经过反渗透处理后，得浓缩物。
本文所述浓缩物用于浸出一次滤渣不仅可以将浓缩物中含有的锂离子一并提取，同时还能高效浸出滤渣中的锂离子，最终提高整体锂回收率。
相比于现有技术，本文的有益效果为：
本文提供了一种废旧磷酸铁锂的回收利用方法，该方法对废旧磷酸铁锂粉末分离浸出得到的沉淀和浸出液分别进行特定再处理，并采用膜浓缩对浸出液中的锂离子进行高度富集以及充分利用处理过程中产生的滤液，最终可以同时高效回收并得到锂盐和磷酸铁产品，整体方法对于废旧磷酸铁锂的锂回收率可以达到95％以上，同时得到的磷酸铁中的杂质元素浓度最高不超过5ppm，磷酸铁产品的质量较高。
附图说明
图1为本文所述废旧磷酸铁锂的回收利用方法的流程示意图。
具体实施方式
为更好地说明本文的目的、技术方案和优点，下面将结合附图和具体实施例对本文作进一步说明。
实施例及对比例中所用材料如无特殊说明，均可通过商业途径获得。
本文各实施例和对比例所用的含废旧磷酸铁锂的极片均是市售回收的磷酸铁锂系电池中的正极极片，主要成分为废旧磷酸铁锂、导电剂及粘结剂，在进行回收利用前均对极片中锂元素、磷元素和铁元素进行了含量检测。
本文所述膜浓缩系统由1～10nm孔径纳滤膜系统和0.4～0.6nm孔径反渗透膜系统组成，所述一次滤液进入膜浓缩系统的速率为400L/h，pH为2～4，压力为1～1.5MPa，所述一次滤液经膜系统浓缩后溶液中的锂离子浓度为20～25g/L。
本文所述各实施例中，二次滤液和三次滤液调节pH至9～10，过滤，随后调节pH至4～6后并再次过滤；所得滤液采用中水系统进行处理，所述中水系统包括精滤-超滤系统和反渗透系统，所述精滤-超滤系统包括依次连接的微孔精密过滤器、板式换热器，超滤装置，与超滤装置连接的超滤产水槽；所述反渗透系统包括依次连接的一级反渗透装置，二级反渗透装置，三级反渗透装置以及对应相连的水槽，所述三级反渗透装置连接终端反渗透装置。
所述滤液流入中水系统后，依次经过精滤-超滤系统的微孔精密过滤器、板式换热器，超滤装置完成精滤、超滤处理，并在超滤产水槽中积累水，该水随后通过一级反渗透装置、二级反渗透装置、三级反渗透装置的反渗透处理后即可得到纯化水，该纯化水循环利用，而收集一级反渗透装置的浓水槽中的液体 并经过终端反渗透装置，得到浓缩物。
实施例1
本文所述废旧磷酸铁锂的回收利用方法的一种实施例，如图1所示，包括以下步骤：
(1)将100g含废旧磷酸铁锂的极片粉末置入1000mL的1mol/L的硫酸溶液中，用蠕动泵泵入30mL浓度为30％的双氧水进行浸出4h，待该选择性提锂的步骤完成后，得浸出液和浸出渣；
(2)将浸出液用氢氧化钙饱和溶液进行pH调节至8.5、50℃沉淀反应2h并过滤出沉淀后，得一次滤液和一次滤渣，完成一步除杂；
(3)将一次滤液经膜系统浓缩后，得到的高浓锂液加入60g沉淀剂碳酸钠在90℃沉淀3h，得锂盐碳酸锂和二次滤液；
(4)在氮气氛围下，将步骤(1)得到浸出渣置入含有500mL的1mol/L的硫酸溶液的反应釜中，反应1h后，随后分阶段加入还原剂单质铁粉及添加剂二氧化钛混合，在50℃下进行反应3h并过滤掉不溶渣，从而实现酸溶除杂，所得混合液转移至另一反应釜并加入1.2MPa氧气在80℃下进行反应6h，过滤，得磷酸铁和三次滤液；所述浸出渣、单质铁粉以及二氧化钛的质量之比为100：31：65；
(5)将二次滤液和三次滤液混合并用氢氧化钠调节至pH至9-10，随后调节pH至4～6并过滤，进入中水系统处理后所得浓缩物pH＝3，所述浓缩物浓水置入一次滤渣并浸出，浸出时的液固比为3mL/g，过滤，得四次滤液和最终无法进一步提锂的混合渣，所述四次滤液按照一次滤液处理步骤进行处理。
实施例2
本文所述废旧磷酸铁锂的回收利用方法的一种实施例，包括以下步骤：
(1)将200g含废旧磷酸铁锂的极片粉末置入1000mL的1mol/L的硫酸溶液中，用蠕动泵泵入60mL浓度为30％的双氧水进行浸出4h，待该选择性提锂的步骤完成后，得浸出液和浸出渣；
(2)将浸出液用浓度30％的液碱氢氧化钠溶液进行pH调节至8.5、50℃沉淀反应2h并过滤出沉淀后，得一次滤液和一次滤渣，完成一步除杂；
(3)将一次滤液经膜系统浓缩后，得到的高浓锂液加入276g沉淀剂十二 水磷酸钠在90℃沉淀3h，得锂盐磷酸锂和二次滤液；
(4)在氮气氛围下，将步骤(1)得到浸出渣置入含有500mL的1mol/L的硫酸溶液的反应釜中，反应2h后，随后分阶段加入还原剂单质铁粉及添加剂二氧化钛、一水磷酸氢钛混合，在80℃下进行反应5h并过滤掉不溶渣，从而实现酸溶除杂，所得混合液转移至另一反应釜并加入1.3MPa氧气在80℃下进行反应6h，过滤，得磷酸铁和三次滤液；所述浸出渣、单质铁粉、二氧化钛以及一水磷酸氢钛的质量之比为100：36：80：80；
(5)将二次滤液和三次滤液按照实施例1相同处理方法处理得到浓缩物，所述浓缩物浓水置入一次滤渣并浸出，浸出时的液固比为4mL/g，过滤，得四次滤液和最终无法进一步提锂的混合渣，所述四次滤液按照一次滤液处理步骤进行处理。
实施例3
本文所述废旧磷酸铁锂的回收利用方法的一种实施例，包括以下步骤：
(1)将200g含废旧磷酸铁锂的极片粉末置入1000mL的1mol/L的硫酸溶液中，用蠕动泵泵入60mL浓度为30％的双氧水进行浸出4h，待该选择性提锂的步骤完成后，得浸出液和浸出渣；
(2)将浸出液用氢氧化钙饱和溶液进行pH调节至8.5、60℃沉淀反应2h并过滤出沉淀后，得一次滤液和一次滤渣，完成一步除杂；
(3)将一次滤液经膜系统浓缩后，得到的高浓锂液加入84g沉淀剂碳酸钠在90℃沉淀3h，得锂盐碳酸锂和二次滤液；
(4)在氮气氛围下，将步骤(1)得到浸出渣置入含有500mL的1mol/L的硫酸溶液的反应釜中，反应3h后，随后分阶段加入还原剂单质铁粉及添加剂一水磷酸氢钛混合，在50℃下进行反应6h并过滤掉不溶渣，从而实现酸溶除杂，所得混合液转移至另一反应釜并加入1.3MPa氧气在80℃下进行反应6h，过滤，得磷酸铁和三次滤液；所述浸出渣、单质铁粉以及一水磷酸氢钛质量之比为100：41：100；
(5)将二次滤液和三次滤液按照实施例1相同处理方法处理得到浓缩物，所述浓缩物浓水置入一次滤渣并浸出，浸出时的液固比为5mL/g，过滤，得四次滤液和最终无法进一步提锂的混合渣，所述四次滤液按照一次滤液处理步骤进 行处理。
实施例4
本文所述废旧磷酸铁锂的回收利用方法的一种实施例，包括以下步骤：
(1)将200g含废旧磷酸铁锂的极片粉末置入1000mL的1mol/L的硫酸溶液中，用蠕动泵泵入60mL浓度为30％的双氧水进行浸出4h，待该选择性提锂的步骤完成后，得浸出液和浸出渣；
(2)将浸出液用氢氧化钙饱和溶液进行pH调节至8.5、50℃沉淀反应2h并过滤出沉淀后，得一次滤液和一次滤渣，完成一步除杂；
(3)将一次滤液经膜系统浓缩后，得到的高浓锂液加入96g沉淀剂碳酸钠在90℃沉淀3h，得锂盐碳酸锂和二次滤液；
(4)在氮气氛围下，将步骤(1)得到浸出渣置入含有500mL的1mol/L的硫酸溶液的反应釜中，随后分阶段加入还原剂单质铁粉及添加剂二水磷酸铁与三氧化二钛的混合物混合，反应2h后，在50℃下进行反应5h并过滤掉不溶渣，从而实现酸溶除杂，所得混合液转移至另一反应釜并加入1.5MPa氧气在80℃下进行反应6h，过滤，得磷酸铁和三次滤液；所述浸出渣、单质铁粉以及二水磷酸铁与三氧化二钛的混合物的质量之比为100：32：85；
(5)将二次滤液和三次滤液按照实施例1相同处理方法处理得到浓缩物，所述浓缩物浓水置入一次滤渣并浸出，浸出时的液固比为7mL/g，过滤，得四次滤液和最终无法进一步提锂的混合渣，所述四次滤液按照一次滤液处理步骤进行处理。
实施例5
本文所述废旧磷酸铁锂的回收利用方法的一种实施例，包括以下步骤：
(1)将200g含废旧磷酸铁锂的极片粉末置入1000mL的1mol/L的硫酸溶液中，用蠕动泵泵入60mL浓度为30％的双氧水进行浸出4h，待该选择性提锂的步骤完成后，得浸出液和浸出渣；
(2)将浸出液用氢氧化钙饱和溶液进行pH调节至8.5、50℃沉淀反应2h并过滤出沉淀后，得一次滤液和一次滤渣，完成一步除杂；
(3)将一次滤液经膜系统浓缩后，得到的高浓锂液加入75g沉淀剂碳酸钠在90℃沉淀3h，得锂盐碳酸锂和二次滤液；
(4)在氮气氛围下，将步骤(1)得到浸出渣置入含有500mL的1mol/L的硫酸溶液的反应釜中，反应2h后，随后分阶段加入还原剂单质铁粉及添加剂八水磷酸亚铁混合，在50℃下进行反应5h并过滤掉不溶渣，从而实现酸溶除杂，所得混合液转移至另一反应釜并加入持续以0.7mL/min速率通入浓度30％的双氧水，在80℃下进行反应6h，过滤，得磷酸铁和三次滤液；所述浸出渣、单质铁粉以及八水磷酸亚铁的质量之比为100：52：100；
(5)将二次滤液和三次滤液按照实施例1相同处理方法处理得到浓缩物，所述浓缩物浓水置入一次滤渣并浸出，浸出时的液固比为6mL/g，过滤，得四次滤液和最终无法进一步提锂的混合渣，所述四次滤液按照一次滤液处理步骤进行处理。
实施例6
本文所述废旧磷酸铁锂的回收利用方法的一种实施例，包括以下步骤：
(1)将200g含废旧磷酸铁锂的极片粉末置入1000mL的1mol/L的硫酸溶液中，用蠕动泵泵入60mL浓度为30％的双氧水进行浸出4h，待该选择性提锂的步骤完成后，得浸出液和浸出渣；
(2)将浸出液用氢氧化钙饱和溶液进行pH调节至8.5、50℃沉淀反应2h并过滤出沉淀后，得一次滤液和一次滤渣，完成一步除杂；
(3)将一次滤液经膜系统浓缩后，得到的高浓锂液加入75g沉淀剂碳酸钠在90℃沉淀3h，得锂盐碳酸锂和二次滤液；
(4)在氮气氛围下，将步骤(1)得到浸出渣置入含有500mL的1mol/L的硫酸溶液的反应釜中，反应2h后，随后分阶段加入还原剂单质铁粉及添加剂二水磷酸铁混合，在50℃下进行反应5h并过滤掉不溶渣，从而实现酸溶除杂，所得混合液转移至另一反应釜并加入持续以1.1mL/min速率通入浓度30％的双氧水，80℃下进行反应6h，过滤，得磷酸铁和三次滤液；所述浸出渣、单质铁粉以及二水磷酸铁的质量之比为100：40：90；
(5)将二次滤液和三次滤液按照实施例1相同处理方法处理得到浓缩物，所述浓缩物浓水置入一次滤渣并浸出，浸出时的液固比为6mL/g，过滤，得四次滤液和最终无法进一步提锂的混合渣，所述四次滤液按照一次滤液处理步骤进行处理。
实施例7
本文所述废旧磷酸铁锂的回收利用方法的一种实施例，包括以下步骤：
(1)将200g含废旧磷酸铁锂的极片粉末置入1000mL的1mol/L的硫酸溶液中，用蠕动泵泵入60mL浓度为30％的双氧水进行浸出4h，待该选择性提锂的步骤完成后，得浸出液和浸出渣；
(2)将浸出液用氢氧化钙饱和溶液进行pH调节至8.5、50℃沉淀反应2h并过滤出沉淀后，得一次滤液和一次滤渣，完成一步除杂；
(3)将一次滤液经膜系统浓缩后，得到的高浓锂液加入75g沉淀剂碳酸钠在90℃沉淀3h，得锂盐碳酸锂和二次滤液；
(4)在氮气氛围下，将步骤(1)得到浸出渣置入含有500mL的1mol/L的硫酸溶液的反应釜中，反应2h后，随后分阶段加入还原剂单质铁粉及添加剂氢氧化铝混合，在50℃下进行反应5h并过滤掉不溶渣，从而实现酸溶除杂，所得混合液转移至另一反应釜并加入持续以0.8mL/min速率通入浓度30％的双氧水，80℃下进行反应6h，过滤，得磷酸铁和三次滤液；所述浸出渣、单质铁粉以及氢氧化铝的质量之比为100：62：80；
(5)将二次滤液和三次滤液按照实施例1相同处理方法处理得到浓缩物，所述浓缩物浓水置入一次滤渣并浸出，浸出时的液固比为6mL/g，过滤，得四次滤液和最终无法进一步提锂的混合渣，所述四次滤液按照一次滤液处理步骤进行处理。
实施例8
本文所述废旧磷酸铁锂的回收利用方法的一种实施例，包括以下步骤：
(1)将200g含废旧磷酸铁锂的极片粉末置入1000mL的1mol/L的硫酸溶液中，用蠕动泵泵入60mL浓度为30％的双氧水进行浸出4h，待该选择性提锂的步骤完成后，得浸出液和浸出渣；
(2)将浸出液用氢氧化钙饱和溶液进行pH调节至8.5、50℃沉淀反应2h并过滤出沉淀后，得一次滤液和一次滤渣，完成一步除杂；
(3)将一次滤液经膜系统浓缩后，得到的高浓锂液加入75g沉淀剂碳酸钠在90℃沉淀3h，得锂盐碳酸锂和二次滤液；
(4)在氮气氛围下，将步骤(1)得到浸出渣置入含有500mL的1mol/L的 硫酸溶液的反应釜中，反应1h后，随后分阶段加入还原剂单质铁粉及添加剂三氧化二钛、八水磷酸亚铁混合，在50℃下进行反应4h并过滤掉不溶渣，从而实现酸溶除杂，所得混合液转移至另一反应釜并加入持续以1.5mL/min速率通入浓度30％的双氧水，80℃下进行反应6h，过滤，得磷酸铁和三次滤液；所述浸出渣、单质铁粉、三氧化二钛、八水磷酸亚铁的质量之比为100：62：80：80；
(5)将二次滤液和三次滤液按照实施例1相同处理方法处理得到浓缩物，所述浓缩物浓水置入一次滤渣并浸出，浸出时的液固比为6mL/g，过滤，得四次滤液和最终无法进一步提锂的混合渣，所述四次滤液按照一次滤液处理步骤进行处理。
对比例1
一种废旧磷酸铁锂的回收利用方法，与实施例3的差别仅在于，所述步骤(5)中的一次滤渣采用纯水直接浸出，浸出时的液固比为5mL/g，过滤，得四次滤液和混合渣，所述四次滤液按照一次滤液处理步骤进行处理。
对比例2
一种废旧磷酸铁锂的回收利用方法，与实施例3的差别仅在于，所述步骤(4)中的氮气氛围换为空气氛围。
对比例3
一种废旧磷酸铁锂的回收利用方法，与实施例3的差别仅在于，所述步骤(4)中不加入添加剂。
对比例4
一种废旧磷酸铁锂的回收利用方法，与实施例7的差别仅在于，所述浸出渣、单质铁粉以及氢氧化铝的质量之比为100：62：300。
对比例5
一种废旧磷酸铁锂的回收利用方法，与实施例5的差别仅在于，所述浸出渣、单质铁粉以及八水磷酸亚铁的质量之比为100：52：400。
对比例6
一种废旧磷酸铁锂的回收利用方法，与实施例5的差别仅在于，所述浸出 渣、单质铁粉以及八水磷酸亚铁的质量之比为100：52：20。
对比例7
一种废旧磷酸铁锂的回收利用方法，与实施例4的差别仅在于，所述步骤(3)中的一次滤液采用市售的MVR蒸发系统进行浓缩。
对比例8
一种废旧磷酸铁锂的回收利用方法，与实施例8的差别仅在于，所述步骤(2)中浸出液调节pH后溶液pH为3。
对比例9
一种废旧磷酸铁锂的回收利用方法，与实施例8的差别仅在于，所述步骤(2)中浸出液调节pH后溶液pH为12。
对比例10
一种废旧磷酸铁锂的回收利用方法，与实施例8的差别仅在于，所述步骤(5)中所述浓缩物的pH＝1。
对比例11
一种废旧磷酸铁锂的回收利用方法，与实施例8的差别仅在于，所述步骤(5)中所述浓缩物的pH＝6。
对比例12
一种废旧磷酸铁锂的回收利用方法，与实施例8的差别仅在于，所述步骤(5)中所述浓缩物获得过程中不经过精滤、超滤处理，除锂元素外的杂质元素总浓度为0.08g/L。
效果例1
为了验证本文所述废旧磷酸铁锂的回收利用方法的高效性，检测统计各实施例和对比例所述方法中制备的磷酸铁的杂质含量、磷酸铁产品的铁、磷元素含量及两者的摩尔含量比，以及磷酸铁产品的比表面积，最后统计所述方法的锂回收率，所述锂回收率的计算方法为100-m(混合渣中的锂)/m(磷酸铁锂极片粉中的锂)；若无中水回用系统，只用纯水洗涤含锂混渣，锂的回收率计算方法为 100-m(混合渣中的锂、磷铁渣中的锂、沉锂母液中的锂)/m(磷酸铁锂极片粉中的锂)，最后对制备的锂盐进行纯度检测。
测试结果如表1、表2和表3所示。
表1
表2
表3


从表1和2可以明显看出，本文所述废旧磷酸铁锂的回收方法经过实施后，锂回收率可以达到96％以上，而制备的磷酸铁产品纯度高，主要的杂质浓度最高不超过5ppm，同时比表面积适中，磷铁比与标准品对应。相比之下，对比例1所述方法中并没有对二次滤液和三次滤液进行回收并对一次滤渣进行浸出，因此无法充分回收废旧磷酸铁锂中的锂离子，锂回收率低；对比例2所述方法中浸出渣的转化过程并没有在氮气气氛下进行，在空气氛围下溶解时会造成部分铁和磷流失，制备产品的铁和磷元素含量较低，且制备的产品比表面积较低；对比例3产品在浸出渣转换时并没有引入添加剂进行协同作用，因此无法实现良好的除杂沉淀效果，钛杂质浓度较高，导致最终制备的产品的钛含量也相对较高，同时磷酸铁产品的产率低；然而对比例4产品中引入的添加剂氢氧化铝含量过高，使得最终产品的铝元素偏高，说明在所述方法中添加剂的添加量不能过多，而类似地，对比例5产品中八水磷酸亚铁的添加量过多，磷酸铁和品质和比表面积均不理想；对比例6中添加剂的添加量过少，与对比例3类似，钛杂质无法有效去除。对比例7采用了相对常规的MVR蒸发系统对一次滤液进行蒸发浓缩，该方法相比于膜浓缩工艺容易造成锂离子的损失；对比例8和对比例9在进行浸出液pH调节时过高或过低，导致制备的锂盐产品杂质浓度过高或者锂回收率过低。而在对比例10和对比例11中，由于对一次滤渣进行浸出时的浓缩物pH过高或过低，导致所述过程的锂离子回收率较低或者所得锂盐的杂质含量较高。对比例12中浓缩物本身的杂质含量过高，因此导致最终的锂盐杂质含量也较高。
最后所应当说明的是，以上实施例仅用以说明本文的技术方案而非对本文保护范围的限制，尽管参照较佳实施例对本申请作了详细说明，本领域的普通技术人员应当理解，可以对本文的技术方案进行修改或者等同替换，但并不脱离本文技术方案的实质和范围。

Claims (10)

  1. 一种废旧磷酸铁锂的回收利用方法，其特征在于，包括以下步骤：
    将含废旧磷酸铁锂的极片置入含第一氧化剂的酸溶液中浸出，得浸出液和浸出渣；
    将浸出液经pH调节至8～9、沉淀杂质及过滤后，得一次滤液和一次滤渣；
    将一次滤液经膜系统浓缩后，加入沉淀剂沉淀，得锂盐和二次滤液；
    将浸出渣在惰性气氛下与酸溶液进行反应，随后加入还原剂及添加剂混合反应，过滤，所得混合液加入第二氧化剂进行反应，过滤，得磷酸铁和三次滤液；所述还原剂为单质铁，所述添加剂为二水磷酸铁、八水磷酸亚铁、一水磷酸氢钛、氢氧化铝、二氧化钛、三氧化二钛中的至少一种；所述浸出渣、还原剂及添加剂的质量之比为100：(20～65)：(50～200)；
    将二次滤液和三次滤液混合并调节pH至9～10，过滤，随后调节pH至4～6后并再次过滤；所得滤液经精滤、超滤和反渗透处理后，得纯化水和pH为2～4的浓缩物，所述浓缩物置入一次滤渣并浸出，过滤，得四次滤液，按照一次滤液处理步骤进行处理。
  2. 如权利要求1所述废旧磷酸铁锂的回收利用方法，其特征在于，所述第一氧化剂为氧气、双氧水、过硫酸钠中的至少一种；所述酸溶液为硫酸、盐酸中的至少一种的水溶液。
  3. 如权利要求1所述废旧磷酸铁锂的回收利用方法，其特征在于，所述膜系统依次包括纳滤膜系统和反渗透膜系统。
  4. 如权利要求1所述废旧磷酸铁锂的回收利用方法，其特征在于，所述沉淀剂为碳酸钠、十二水磷酸钠中的至少一种，所述沉淀时的温度为80～100℃，时间为2～4h。
  5. 如权利要求1所述废旧磷酸铁锂的回收利用方法，其特征在于，所述浸出渣与还原剂及添加剂进行反应的时间为3～6h。
  6. 如权利要求1所述废旧磷酸铁锂的回收利用方法，其特征在于，所述第二氧化剂为氧气、双氧水中的一种。
  7. 如权利要求6所述废旧磷酸铁锂的回收利用方法，其特征在于，所述第二氧化剂为双氧水时，所述双氧水的添加速率为0.7～1.1mL/min。
  8. 如权利要求6所述废旧磷酸铁锂的回收利用方法，其特征在于，所述第二氧化剂为氧气时，所述通入的氧气的压力为1.2～1.5MPa。
  9. 如权利要求1所述废旧磷酸铁锂的回收利用方法，其特征在于，所述混合液与第二氧化剂反应时的温度≥80℃。
  10. 如权利要求1所述废旧磷酸铁锂的回收利用方法，其特征在于，所述浓缩物浸出一次滤渣时的单位用量为3～7mL/g。
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120097309A (zh) * 2025-05-09 2025-06-06 合肥国轩电池材料有限公司 一种废旧磷酸铁锂回收制备磷酸铁锂的方法
CN120229696A (zh) * 2025-04-28 2025-07-01 安徽先进建筑材料研究院有限公司 一种利用废旧电池制备磷酸铁的装置及方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109193059A (zh) * 2018-09-26 2019-01-11 王书珍 一种磷酸铁锂废料的再生处理方法
CN109950651A (zh) * 2019-04-03 2019-06-28 中南大学 一种废旧磷酸铁锂电池回收碳的综合处理方法
CN112678791A (zh) * 2020-12-25 2021-04-20 湖南邦普循环科技有限公司 一种磷酸铁锂废料中锂的回收方法及其应用
CN114572950A (zh) * 2022-01-28 2022-06-03 宜昌邦普宜化新材料有限公司 高纯磷酸铁的制备方法及其应用
CN115304042A (zh) * 2022-08-03 2022-11-08 郑州中科新兴产业技术研究院 一种废旧磷酸铁锂回收制备电池级磷酸铁的方法
CN116002646A (zh) * 2022-12-30 2023-04-25 中南大学 一种废旧磷酸铁锂电池中有价组分全资源化回收的方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109193059A (zh) * 2018-09-26 2019-01-11 王书珍 一种磷酸铁锂废料的再生处理方法
CN109950651A (zh) * 2019-04-03 2019-06-28 中南大学 一种废旧磷酸铁锂电池回收碳的综合处理方法
CN112678791A (zh) * 2020-12-25 2021-04-20 湖南邦普循环科技有限公司 一种磷酸铁锂废料中锂的回收方法及其应用
CN114572950A (zh) * 2022-01-28 2022-06-03 宜昌邦普宜化新材料有限公司 高纯磷酸铁的制备方法及其应用
CN115304042A (zh) * 2022-08-03 2022-11-08 郑州中科新兴产业技术研究院 一种废旧磷酸铁锂回收制备电池级磷酸铁的方法
CN116002646A (zh) * 2022-12-30 2023-04-25 中南大学 一种废旧磷酸铁锂电池中有价组分全资源化回收的方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120229696A (zh) * 2025-04-28 2025-07-01 安徽先进建筑材料研究院有限公司 一种利用废旧电池制备磷酸铁的装置及方法
CN120229696B (zh) * 2025-04-28 2025-10-28 安徽先进建筑材料研究院有限公司 一种利用废旧电池制备磷酸铁的装置及方法
CN120097309A (zh) * 2025-05-09 2025-06-06 合肥国轩电池材料有限公司 一种废旧磷酸铁锂回收制备磷酸铁锂的方法
CN120097309B (zh) * 2025-05-09 2025-07-22 合肥国轩电池材料有限公司 一种废旧磷酸铁锂回收制备磷酸铁锂的方法

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