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EP-4739625-A1 - A METHOD FOR PROCESSING SPENT LITHIUM IRON PHOSPHATE BATTERIES

EP4739625A1EP 4739625 A1EP4739625 A1EP 4739625A1EP-4739625-A1

Abstract

The present invention relates to a method for processing spent lithium iron phosphate batteries. The present invention provides an environment-friendly, industrially applicable and an economical method for processing spent lithium iron phosphate batteries that follows simple physical and chemical processes to recover valuable metal for reuse or reutilisation. The method for processing spent lithium iron phosphate batteries of the present invention exhibits percentage recovery rate greater than 95% and the recovered material is having purity in a range of 98-99%.

Inventors

  • BARIK, Smruti Prakash
  • PRABAHARAN, G
  • KUMAR, Bhuvnesh
  • KUMAR, NITIN
  • KULKARNI, AMIT
  • GUPTA, NITIN

Assignees

  • Attero Recycling Pvt. Ltd.

Dates

Publication Date
20260513
Application Date
20240503

Claims (11)

  1. 1. A method for processing spent lithium iron phosphate (LFP) batteries, characterized in that, the method comprising the steps of: a) obtaining cells and other components from dismantled and discharged spent lithium iron phosphate (LFP) batteries; b) shredding the cells obtained in step (a) to obtain a shredded material; c) roasting the shredded material of step (b) at a pre-defmed temperature for a pre-defmed time to remove organic matrix and obtaining a roasted material; d) treating the roasted material of step (c) by a physical process to obtain a slurry and a metal part separately; e) filtering the slurry of step (d) to obtain a cake and filtrate and reusing the filtrate in next batch; f) agitating the cake obtained in step (e) with a suitable reagent and water for 3-5 times for a pre-determined time to obtain a leached slurry; g) filtering the leached slurry of step (f) to obtain a leach liquor and a residue; h) precipitating selectively iron from the leach liquor of step (h) at a pre-defmed pH with a suitable precipitating condition to obtain a precipitated cake and a lithium containing filtrate separately; i) taking the lithium containing filtrate of step (h) for lithium recovery and washing the precipitated cake obtained in step (h) with water to remove free sodium salt and obtaining a washed cake; and j) drying the washed cake of step (i) at a pre-determined temperature for 2-3 hours to recover iron phosphate.
  2. 2. The method for processing spent LFP batteries as claimed in claim 1, wherein the other components in step (a) include printed circuit board, plastic, steel and rubber.
  3. 3. The method for processing spent LFP batteries as claimed in claim 1, wherein the shredding in step (b) is carried out with a twin shaft shredder having an output size in a range of 6- 14mm.
  4. 4. The method for processing spent LFP batteries as claimed in claim 1, wherein the pre-defmed temperature and pre-defmed time of step (c) is in a range of 400-600°C and 2-3 hours, respectively and the organic matrix obtained in step (c) includes binders and electrolytes.
  5. 5. The method for processing spent TFP batteries as claimed in claim 1, wherein the physical process in step (d) includes washing of the roasted material with water followed by wet sieving to obtain said slurry and the metal part separately.
  6. 6. The method for processing spent TFP batteries as claimed in claim 1, wherein the metal part obtained in step (d) includes mix foils having size in a range of l-3mm.
  7. 7. The method for processing spent TFP batteries as claimed in claim 1, wherein the suitable reagent in step (f) is sulphuric acid in an amount ranging from 0.4-0.6 times weight of the cake obtained in step (e) and the predetermined time to obtain the leached slurry of step (f) is 2-4 hours.
  8. 8. The method for processing spent TFP batteries as claimed in claim 1, wherein the suitable precipitating condition of step (h) includes agitating the leach liquor of step (h) with 30% w/v soda ash solution and 0.5-2% v/v hydrogen peroxide for 2-3 hours followed by filtration and the pre-defmed pH in step (h) is in a range of 1.0- 3.0.
  9. 9. The method for processing spent TFP batteries as claimed in claim 1, wherein the lithium containing filtrate obtained in step (h) is having lithium concentration in a range of 2.8-2.9g/F.
  10. 10. The method for processing spent TFP batteries as claimed in claim 1 wherein the pre-determined temperature in step (j) is in a range of 110°C and the recovered iron phosphate in step (j) is having purity in a range of 98-99%.
  11. 11. The method for processing spent LFP batteries as claimed in claim 1, wherein said method recovers iron in form of iron phosphate having percentage recovery in a range of 95-98%.

Description

“A METHOD FOR PROCESSING SPENT LITHIUM IRON PHOSPHATE BATTERIES” FIELD OF THE INVENTION The present invention relates to the field of waste recycling processes. More particularly, the present invention relates to a method for processing spent lithium iron phosphate batteries that involve simple physical and chemical processes to recover valuable metals for reuse or reutilisation. BACKGROUND OF THE INVENTION Lithium-ion batteries (LIBs) are widely utilized in portable gadgets and electric vehicles due to good performance, high discharge voltage and energy density. With the emergence of electric vehicles, utilizing lithium-ion batteries as energy storage devices, the demand for lithium-ion batteries throughout the entire industry is tremendously increasing. Meanwhile, there is also an increase in waste generated from discarded lithium-ion batteries and other batteries that are posing a challenge to the existing recycling processes. However, because of the high energy density, high safety and low price of lithium-ion batteries, recycling waste lithium-ion batteries is difficult. Because of the toxic chemical compounds in these waste batteries, direct disposal causes major environmental difficulties. The mismanagement of battery waste, if not handled properly, poses negative influence on the environment and resources. Although lithium iron phosphate (LiFePO4) material is relatively environmental friendly, the corresponding spent LIBs cause potential environmental problems by the electrolyte or improper disposal. Conventionally, waste lithium iron phosphate (LFP) batteries are recycled using two methods, which are pyrometallurgy (i.e., direct regeneration) and hydrometallurgy (i.e., individual metal leaching). However, emission of toxic gases (such as sulphur dioxide, hydrogen sulfide, carbon dioxide) at high temperatures in these methods was subsequently discovered to be harmful to the environment. Furthermore, the hydrometallurgical recovery of full metal ions (i.e., Li, Fe and P) in solution raises the process cost due to the excessive usage of minerals. CN109179359A discloses a method of extracting lithium and ferric phosphate from lithium iron phosphate (LiFePO4) waste material, comprising the steps of immersing lithium iron phosphate powder with sodium hydroxide (NaOH) to obtain an aluminum removal material; performing an aerobic calcination reaction on the aluminum removal material to obtain a calcined material; cooling the calcined material and adding acid to obtain pickle liquor and iron phosphate; performing solid-liquid separation on the pickle liquor to obtain an iron phosphate solid and an acidic lithium liquid; washing the iron phosphate and drying to obtain battery-grade iron phosphate and regulating pH value of the acidic lithium liquid to alkaline level and filtering to obtain a purified lithium liquid. This citation requires an oxygen environment and a high temperature range upto 1050°C to carry out roasting process. CN112410556B discloses a method for recovering waste lithium iron phosphate powder. The recovery method comprises the steps of adding water and carrying out stirring to obtain lithium iron phosphate waste slurry; adding an acid solution and an oxidant into the lithium iron phosphate waste slurry to obtain acidic lithium iron phosphate waste slurry; adjusting pH to obtain a first lithium-containing solution and first filter residues; adding a second alkaline regulator into the first lithium-containing solution and adjusting pH to obtain a second lithium-containing solution and second filter residues; adding carbonate into the second lithium containing solution to obtain lithium carbonate precipitates; collecting the first filter residues and the second filter residues, washing and then adding a hydrochloric acid solution to obtain an iron-containing solution and third filter residues and adjusting pH to obtain iron phosphate colloid and calcining the iron phosphate colloid to obtain iron phosphate powder. Although, the citation provides the high recovery rate for lithium and recycling of iron phosphate, however, the method is complex, lengthy and tedious. In the process of calcining the iron phosphate colloid, ammonium chloride gas is discharged, ammonium chloride can decompose ammonia and hydrogen chloride at high temperature, therefore, tail gas generated in the process of calcining the iron phosphate colloid cannot be directly discharged to the environment as the environment can be polluted, through collecting the tail gas, therefore, the tail gas is prevented from being directly discharged to the environment. The discharging process for the generated tail gas adds additional cost that makes the method expensive. WO201836568A1 discloses a method for extracting lithium carbonate from lithium iron phosphate battery waste material, where the lithium iron phosphate material is subjected to oxidative acid hydrolysis, alkali is added to remove iron, and after lithium carbonate is p