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JP-7857304-B2 - Selective recovery of Li

JP7857304B2JP 7857304 B2JP7857304 B2JP 7857304B2JP-7857304-B2

Inventors

  • コーエン・ヴァンデール

Assignees

  • ゲリオン・テクノロジーズ・ピーティーワイ・リミテッド

Dates

Publication Date
20260512
Application Date
20210920
Priority Date
20201015

Claims (14)

  1. A method for selectively removing Li from an input material containing Li and one or more transition metals, The steps include bringing the input material into contact with a leaching medium containing formic acid and sulfate , The process includes the step of leaching Li from the input material to form a leachate, A method wherein the concentration of formic acid in the leaching medium is at least 70% by weight.
  2. The method according to claim 1, wherein the input material includes, in addition to Li, one or more of nickel, manganese, and/or cobalt.
  3. The method according to claim 1 or 2, wherein the input material includes nickel, manganese, and cobalt in addition to Li.
  4. The method according to any one of claims 1 to 3, wherein the concentration of formic acid in the leaching medium is at least 80% by weight.
  5. The method according to any one of claims 1 to 4, wherein the concentration of formic acid in the leaching medium is at least 95% by weight.
  6. The method according to any one of claims 1 to 5 , wherein the step of leaching Li from the input material to form a leachate includes heating to a temperature of at least 60°C.
  7. The method according to any one of claims 1 to 6 , wherein the step of leaching Li from the input material to form a leachate includes heating to a temperature of at least 80°C.
  8. The method according to any one of claims 1 to 7 , wherein the step of leaching Li from the input material to form a leachate includes heating to at least the boiling point of the leaching medium.
  9. The method according to any one of claims 1 to 8 , wherein the step of leaching Li from the input material to form a leachate is further comprising heating under reflux.
  10. The method according to any one of claims 1 to 9 , wherein the leaching medium comprises a nonmetallic sulfate.
  11. The method according to any one of claims 1 to 10 , wherein the leaching medium comprises ( NH₄ ) ₂SO₄ .
  12. The method according to any one of claims 1 to 1 , wherein the leaching is performed by stirring the input material .
  13. The method according to claim 1 or 2 , wherein the stirring is performed by stirring.
  14. The method according to claim 1, 2 , or 1, 3 , wherein the stirring is performed by ultrasonic waves.

Description

This specification relates to the selective recovery of Li from an input material containing a mixture of Li and one or more transition metals. The number of portable electronic devices (e.g., smartphones and laptops) that require rechargeable batteries is increasing year by year. As environmental concerns grow, the automotive industry is seeking alternatives to internal combustion engines, and rechargeable batteries offer one solution. With increasing consumer adoption of hybrid and all-electric vehicles powered by rechargeable batteries, global demand for rechargeable batteries is expected to continue to rise. Modern rechargeable batteries typically contain cathode materials based on transition metal oxide frameworks containing intercalated lithium. Examples include LiCoO₂ , LiMn₂O₄ , LiFePO₄ , LiNiCoAlO₂ , and LiNi x Mn y Co z O₂ ("NMC"). One material showing promise for automotive applications is "NMC" (lithium-nickel-manganese-cobalt), represented by the general formula LiNi x Mn y Co z O₂ , where x + y + z = 1. It is desirable to provide routes for recovering and recycling the metals used in the cathode materials of batteries. This is particularly important for Co, Ni, and Li, and to a lesser extent for Mn. The recovery of Li, Ni, Mn, and Co from NMC materials has been previously studied. In a typical process, these metals are solubilized from cathode scrap using an acidic leaching medium (e.g., sulfuric acid) to form a leachate containing metal ions, which is then separated by a series of precipitates using pH adjustment and/or solvent extraction. Fe, Al, and Cu can be removed from the leachate by various methods, including sulfidation or precipitation using NaOH. Mn, Co, and Ni are typically separated from the leachate by precipitation and/or solvent extraction, although Mn, Co, and Ni are often contaminated with Li impurities. Li is usually the last material remaining in the solution, precipitating , for example, as Li₂CO₃ . However, at this stage, the leachate contains sodium ions previously introduced when Fe, Al, and Cu precipitate and during solvent extraction. Li precipitation often uses Na₂CO₃ as a carbonate source, tending to produce Li₂CO₃ contaminated with Na₂CO₃ , making it difficult to obtain high-purity Li from Li₂CO₃ . Therefore, it is advantageous if Li can be removed from the cathode scrap upstream before pH adjustment. In a paper by Gao et al. (Environ. Sci. Technol. 2017, 51, 1662-1669), the authors describe the recovery of Li, Ni, Mn, and Co from NMC cathode scrap using a leaching solution containing aqueous formic acid and hydrogen peroxide. Formic acid plays a dual role in this process. Firstly, formic acid acts as a reducing agent to convert insoluble +3 transition metal ions present in NMC into soluble +2 ions. Hydrogen peroxide is added to assist this reduction. Secondly, formic acid forms complexes with Li(I), Ni(II), Mn(II), and Co(II) ions in solution. In the aforementioned Gao paper, the effects of parameters including reducing agent content, formic acid concentration, solid-liquid ratio (S/L), temperature, and time on the selectivity of metals extracted from cathode scrap were investigated. In one experimental set, the recovery of Li, Ni, Mn, and Co from used NMC cathode material was investigated by treating the material with a formic acid solution for a period of 120 minutes at a leaching temperature of 60°C. As the formic acid concentration increased, the leaching rate of each metal increased. In each case, a larger proportion of Li leached compared to the amounts of Ni, Mn, or Co, but in all cases, significant amounts of Ni, Mn, and Co were present in the leaching solution, and significant amounts of Ni, Mn, and Co required separation by a subsequent precipitation step. Similar results were obtained when a mixture of diluted formic acid and H₂O₂ was used as the leaching medium. Over time, the Co(II), Ni(II), and Mn(II) ion content in the leachate reached its maximum and then began to decrease due to the precipitation of ions as hydroxides, although the leachate consistently contained significant amounts of transition metal ions. Gao et al. (Environ.Sci.Technol.2017, 51, 1662-1669) The results were obtained using NMC-111 as the input material, with 98% formic acid as the leaching medium. The image on the left shows the selectivity of the leaching medium, and the image on the right shows the efficiency of the leaching medium.The results were obtained using NMC-111 as the input material, with 98% formic acid used as the leaching medium together with ( NH₄ ) ₂SO₄ as an additive. The image on the left shows the selectivity of the leaching medium, and the image on the right shows the efficiency of the leaching medium.The results were obtained using NMC-111 as the input material, with a 77.5% by weight formic acid/22.5% by weight water azeotrope as the leaching medium. The image on the left shows the selectivity of the leaching medium, and the image on the right shows the ef