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CN-121976061-A - Method for synchronously extracting lithium element in ternary and lithium iron phosphate positive electrode material at ultralow cost

CN121976061ACN 121976061 ACN121976061 ACN 121976061ACN-121976061-A

Abstract

The invention provides a method for synchronously extracting lithium elements in ternary and lithium iron phosphate anode materials with ultra-low cost. The method comprises the steps of mixing eutectic solvent with the mixed materials of waste lithium iron phosphate and waste ternary lithium, heating, introducing carbon dioxide for reaction, filtering, precipitating iron, nickel, manganese, cobalt and the like to form and collecting, and further treating the filtrate containing lithium elements to realize selective extraction of the lithium elements. The invention uses the eutectic solvent to mix with the mixed material containing the ternary positive electrode material and the lithium iron phosphate positive electrode material at the same time, and introduces carbon dioxide for reaction, thereby realizing the synchronous leaching of lithium in one step of the two main stream lithium battery materials, avoiding the complex process of separate treatment in the traditional process, improving the selectivity and recovery rate of lithium recovery, avoiding the harsh conditions of strong acid, strong alkali, high temperature and high pressure, reducing the energy consumption and environmental risk, recycling the core reagent, reducing the recovery cost and reducing the discharge of waste liquid and waste gas.

Inventors

  • LIU KELU
  • WANG TAO
  • LI LIMIN
  • Yan Ruguo
  • Hua Runjie

Assignees

  • 江西天奇金泰阁钴业有限公司

Dates

Publication Date
20260505
Application Date
20260129

Claims (10)

  1. 1. The method for synchronously extracting the lithium element in the waste ternary cathode material and the waste lithium iron phosphate cathode material is characterized by comprising the following steps of: S1, mixing a hydrogen bond acceptor and a hydrogen bond donor, adding water, and heating and stirring to obtain a eutectic solvent; S2, providing a mixed material of a waste ternary cathode material and a waste lithium iron phosphate cathode material; S3, mixing the eutectic solvent of the S1 and the mixed material of the S2, heating, and introducing carbon dioxide to react under 0.4-0.6 MPa; And S4, after the reaction is finished, filtering, collecting filtrate, heating the filtrate until precipitation is completely separated out, filtering again, washing and collecting the precipitation to finish the extraction of lithium in the waste ternary cathode material and the waste lithium iron phosphate cathode material.
  2. 2. The method of claim 1, wherein in S1, the hydrogen bond acceptor comprises choline chloride and the hydrogen bond donor comprises at least one of hydroquinone, resorcinol.
  3. 3. The method according to any one of claims 1-2, wherein in S1, the mass ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:2-3; the addition amount of the water is 3-6wt% of the total mass of the hydrogen bond acceptor and the hydrogen bond donor.
  4. 4. The method according to claim 1, wherein in S1, the temperature of the heating and stirring is 60 to 80 ℃.
  5. 5. The method according to claim 1, wherein in S2, the mass ratio of the waste ternary cathode material to the waste lithium iron phosphate cathode material in the mixed material is 1:1.
  6. 6. The method according to claim 1 or 5, wherein the waste ternary positive electrode material is obtained by mechanically crushing a waste ternary positive electrode sheet, and then separating the current collector from the ternary positive electrode material to obtain the waste ternary positive electrode material; the waste lithium iron phosphate anode material is obtained by mechanically crushing and sorting waste lithium iron phosphate anode sheets to separate a current collector from the waste lithium iron phosphate anode material.
  7. 7. The method according to claim 1, wherein in S3, the mass ratio of the eutectic solvent to the mixed material is 6-8:1.
  8. 8. The method of claim 1, wherein in S3, the temperature is raised to 50-60 ℃.
  9. 9. The method of claim 1, wherein in S3, the reaction time is 8-10 hours.
  10. 10. The method of claim 1, wherein in S4, the heating temperature is 80-90 ℃.

Description

Method for synchronously extracting lithium element in ternary and lithium iron phosphate positive electrode material at ultralow cost Technical Field The invention relates to the technical field of new energy material recovery and regeneration, in particular to a method for synchronously extracting lithium elements in ternary and lithium iron phosphate anode materials with ultra-low cost. Background With the large-scale application of new energy automobiles and energy storage equipment, the scrapping amount of lithium batteries (mainly ternary lithium batteries and lithium iron phosphate batteries) is increased in an explosive manner. Lithium is used as a core element of a lithium battery, the resource scarcity is increasingly remarkable, and how to effectively recycle lithium elements in waste lithium iron phosphate and ternary materials is a hot spot of current research in the industry. The traditional recovery method of lithium in ternary materials takes leaching-before-separating as a core, and main flow processes comprise pyrometallurgy and wet acid leaching. Wherein, the pyrometallurgy is to mix the waste ternary material with the reducer and flux, bake at about 800 ℃ to convert lithium into soluble lithium salt (such as Li 2CO3), and extract lithium by water or acid leaching. The method has the advantages of higher energy consumption, large amount of generated waste gas, pollution problem and incompatibility with the lithium iron phosphate material. Wet acid leaching is to use strong acid (such as hydrochloric acid, sulfuric acid, nitric acid) and hydrogen peroxide as leaching agents to make Li +、Ni²+、Co²+、Mn²+ enter solution synchronously, and then to separate lithium by extraction, precipitation and other methods. The method has the advantages of high consumption of strong acid (1.5 tons of strong acid is consumed for each ton of materials), high environmental protection treatment cost, synchronous leaching of lithium and other metal ions, poor selectivity, long subsequent separation flow, and incapability of synchronously treating mixed waste due to the fact that the strong acid damages phosphate groups in lithium iron phosphate. Traditional methods of recovering lithium from lithium iron phosphate include strong acid leaching and dilute acid leaching. The strong acid leaching process is to break down the olivine structure by sulfuric acid and hydrogen peroxide at 90-110 ℃ to leach Li + and Fe2 +, adjust ph to precipitate ferric salt, then add sodium carbonate to form lithium carbonate, and recycle lithium element. The scheme is similar to a ternary material lithium recovery mode, a large amount of sulfuric acid is consumed, wastewater treatment cost is high, and lithium selectivity is poor. The dilute acid leaching process adopts dilute sulfuric acid or weaker acid phosphoric acid, an oxidant is added, the pH value is strictly controlled, ferrous iron is oxidized into ferric iron, the ferric iron exists in a ferric phosphate precipitation form, lithium ions are leached into the solution, and the preferential extraction of lithium is completed. This solution reduces the amount of acid used, but still inevitably produces waste water, and iron is inevitably introduced into the recovered lithium solution, with lower purity. At present, the common problem of the traditional recovery process for recovering lithium in ternary lithium materials and lithium iron phosphate is that the ternary materials and the lithium iron phosphate materials cannot be synchronously treated, the energy consumption and the environmental protection cost are high depending on strong acid or high temperature conditions, the requirements on equipment are severe, the lithium extraction selectivity is poor, the lithium is easy to mix with other metal ions, the subsequent separation difficulty is high, and the recovery rate is low; Based on the method, a lithium extraction technology which can synchronously process two materials, has mild conditions, low cost and high selectivity is developed, and has important significance for promoting the green and efficient recovery of the waste lithium batteries. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a method for synchronously extracting lithium elements in ternary and lithium iron phosphate anode materials with ultra-low cost. According to the invention, through the use of the eutectic solvent, the eutectic solvent reacts with the mixture containing the ternary positive electrode material and the lithium iron phosphate positive electrode material at the same time under the condition of introducing carbon dioxide, so that the 'one-step synchronous lithium leaching' of two main stream lithium battery materials is realized, the complex process that the traditional process needs separate treatment is avoided, the selectivity and recovery rate of lithium recovery are improved, harsh conditions such as strong acid, strong base, high temperature and