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CN-121992206-A - Method for cooperatively leaching anode material of retired lithium ion battery

CN121992206ACN 121992206 ACN121992206 ACN 121992206ACN-121992206-A

Abstract

The invention discloses a method for cooperatively leaching out a positive electrode material of a retired lithium ion battery, and belongs to the field of resource recycling. Preparing biological acid and ferric iron solution respectively by using thiobacillus ferrooxidans, selectively leaching lithium in ternary positive electrode black powder by using biological acid to obtain lithium-containing leaching solution and acid leaching slag, replacing and leaching lithium iron phosphate positive electrode black powder by using ferric iron solution to obtain lithium-and ferrous iron-containing leaching solution, mixing the acid leaching slag and ferrous iron-containing leaching solution, and reducing and leaching nickel, cobalt and manganese in the acid leaching slag by using ferrous iron. The method can realize that the lithium leaching rate is more than 96%, the comprehensive leaching rate of nickel, cobalt and manganese is close to 100%, the concentration of the lithium iron phosphate treated slurry reaches 15%, ferric ions form ferric iron, ferrous iron and ferric iron internal circulation in the system, so that the consumption of chemical reagents and the generation of waste residues are greatly reduced, and the method has the advantages of high leaching efficiency, high treatment concentration, short period, low cost, environment friendliness and the like, and is suitable for efficient collaborative leaching of retired ternary and lithium iron phosphate anode materials.

Inventors

  • YU XIAOLONG
  • LIU TIAN
  • ZHANG JUNFENG

Assignees

  • 湘潭大学

Dates

Publication Date
20260508
Application Date
20260410

Claims (10)

  1. 1. The method for cooperatively leaching the anode material of the retired lithium ion battery is characterized by comprising the following steps of: S1, respectively preparing biological acid and a solution containing Fe 3+ by using thiobacillus ferrooxidans; s2, mixing the biological acid obtained in the step S1 with ternary positive black powder, performing first-stage leaching, and separating to obtain a lithium-containing leaching solution and ternary acid leaching residues; S3, mixing the solution containing Fe 3+ obtained in the step S1 with lithium iron phosphate positive electrode black powder to form slurry, performing second-stage leaching, and separating to obtain leaching liquid containing Fe 2+ and Li + ; S4, mixing the ternary acid leaching slag obtained in the step S2 with the leaching solution containing Fe 2+ obtained in the step S3, and leaching in a third stage to leach nickel, cobalt and manganese.
  2. 2. The method according to claim 1, wherein in step S4, fe 2+ in the leachate containing Fe 2+ is used as a reducing agent to reduce the higher nickel, cobalt and manganese oxides in the ternary acid leaching residue obtained in step S2 to acid-soluble lower oxides, while Fe 2+ is oxidized to Fe 3+ ,Fe 3+ to hydrolyze to H + and realize acid leaching of nickel, cobalt and manganese.
  3. 3. The method according to claim 1 or 2, wherein in the step S1, the preparation condition of the biological acid comprises the mass fraction of sulfur in the culture medium being 0.5-2.0%, the culture time being 6-10 days, the pH at the end of the culture being 0.8-1.2, the acidity being 0.25-0.40 mol-H + /L.
  4. 4. The method according to claim 1 or 2, wherein in the step S1, the preparation condition of the solution containing Fe 3+ comprises that a culture medium contains a source of Fe 2+ , feSO 4 ·7H 2 O is supplemented in a semi-continuous mode, the culture time is 6-10 days, the concentration of Fe 3+ at the end point is 40-60 g/L, and the pH is 1.5-2.0.
  5. 5. The method according to claim 1, wherein in the step S2, in the first leaching step, the liquid-solid ratio of the biological acid to the ternary positive electrode black powder is 50-100:1 ml/g, the reaction temperature is 25-35 ℃, the reaction time is 2-4 hours, and the rotating speed of the reactor is 250-350 rpm.
  6. 6. The method according to claim 1, wherein in the second leaching step S3, the slurry concentration of the lithium iron phosphate positive electrode black powder is 5-15%, the molar ratio of Fe 3+ to iron in the lithium iron phosphate is 1 (0.9-1.1), the reaction time is 20-40 minutes, the reaction temperature is 25-35 ℃, and the rotational speed of the reactor is 250-350 rpm.
  7. 7. The method according to claim 1, wherein in the third leaching step S4, the mixing ratio of the leaching solution containing Fe 2+ obtained in the step S3 and the ternary acid leaching slag obtained in the step S2 is configured according to the mass ratio of Fe 2+ to the initial ternary positive electrode black powder of (1.0-1.5): 1, the reaction time is 50-120 minutes, the reaction temperature is 25-35 ℃, and the rotating speed of the reactor is 250-350 rpm.
  8. 8. The method according to claim 1, 2 or 7, wherein in the third leaching step S4, the reaction end point pH is 2.0 to 2.5, the residual concentration of Fe 2+ is 10 to 15 g/L, and the formation concentration of Fe 3+ is 30 to 40 g/L.
  9. 9. A reaction system for synergistic leaching of a retired lithium ion battery positive electrode material is characterized by comprising biological acid generated by metabolism of thiobacillus ferrooxidans and a solution containing Fe 3+ , leaching liquid containing Fe 2+ generated by reaction of the solution containing Fe 3+ and lithium iron phosphate positive electrode black powder, ternary acid leaching slag generated by reaction of the biological acid and the ternary positive electrode black powder, and a reduction-acid leaching synergistic reaction system formed by mixing the leaching liquid containing Fe 2+ and the ternary acid leaching slag.
  10. 10. Use of the method according to any one of claims 1 to 8 or the reaction system according to claim 9 for leaching of valuable metals in retired lithium ion battery cathode materials, wherein the valuable metals comprise at least one of lithium, nickel, cobalt, manganese, iron.

Description

Method for cooperatively leaching anode material of retired lithium ion battery Technical Field The invention belongs to the field of resource recycling, and mainly relates to a method for cooperatively leaching a positive electrode material of a retired lithium ion battery. Background The lithium ion battery is used as a core component of the new energy automobile, and the lithium ion battery is currently stepped into a large-scale retired scrapping stage. The positive electrode material is the most valuable component in the lithium ion battery, mainly comprises lithium iron phosphate (LFP), ternary lithium (NCM) and other types, and contains nickel, cobalt, lithium and other key metals. These metals are expensive and highly dependent on importation, and their recycling has important significance for relieving the supply pressure of upstream resources and guaranteeing the safety of industrial chains. However, the retired lithium ion battery has complex sources and various types, and how to construct a green and efficient recovery system to realize efficient leaching of key metals in the retired lithium ion battery is still a key technical problem facing the current situation. At present, the recovery method of the lithium ion battery anode material mainly comprises pyrometallurgy and hydrometallurgy. The hydrometallurgy can leach valuable metals efficiently, but needs to consume a large amount of chemical reagents such as strong acid, strong alkali, oxidant, reducing agent and the like, is easy to produce secondary pollution and has higher environmental risk. In view of the above problems, bioleaching techniques have received widespread attention in recent years. The technology utilizes the metabolism of microorganisms to realize the dissolution and leaching of metals, and has the advantages of low cost, environmental friendliness and the like. However, existing bioleaching techniques still face a number of challenges when applied to the recovery of lithium ion battery cathode materials. Firstly, in the biological direct contact leaching process, the toxicity of the metal component in the positive electrode black powder inhibits the activity of microorganisms, so that the concentration of slurry in a leaching system is low (usually only about 1% w/v), the leaching period is long (7-15 days), or stress resistance domestication (such as CN 119464724B) is required for strains. Secondly, the existing research focuses on the leaching of a single type of positive electrode material (lithium iron phosphate or ternary lithium), and the research on the multi-source black powder collaborative leaching technology with complex sources and mixed types is less. The above problems limit the large-scale application of bioleaching technology in the field of lithium battery recovery. In the leaching study of lithium iron phosphate cathode materials, ferric ions (Fe 3+) proved to play an important role. The prior patent literature (such as CN120728070B, CN117165770A, CN117163928 a) discloses a method for leaching lithium iron phosphate by using ferric salt, which is based on the principle that Fe 3+ and LiFePO 4 undergo a displacement reaction to release Li + and Fe 2+ into solution. However, ferric salts (such as ferric sulfate) are expensive, adding to the cost of the process. In the leaching process of the ternary cathode material, fe 2+ can be used as a reducing agent to reduce the oxides of nickel, cobalt and manganese which are difficult to dissolve in acid in the ternary cathode material into the oxides of acid-soluble low valence state so as to promote the leaching of the ternary cathode material. In the field of biometallurgy, acidithiobacillus ferrooxidans (Acidithiobacillus ferrooxidans, abbreviated as a. Ferrooxidans) is a common model strain. The strain is a gram-negative and chemolithotrophic strain, can utilize reducing sulfur to generate biological acid, and can oxidize Fe 2+ into Fe 3+. Based on the metabolic characteristics, the novel bio-chemical synergistic treatment process can be theoretically constructed by preparing an acidic medium and an oxidant required by leaching through a microbial metabolic process at low cost and further combining with non-contact chemical leaching. However, how to organically combine the biological metabolism characteristics with the chemical leaching behaviors of different types of positive electrode materials, realize the step-by-step cooperative treatment of two typical positive electrode materials of lithium iron phosphate and ternary lithium, and construct an internal recycling mechanism of iron ions, and no disclosure report exists at present. In conclusion, the development of the synergistic leaching method which can meet the requirements of high efficiency, low cost and green environmental protection and is suitable for the multi-source retired lithium ion battery anode material has important practical significance and industrialization value. Disclosure of Invention