Lithium iron phosphate (LFP) battery recycling
The inventions described herein provide methods and systems for recycling lithium iron phosphate batteries, including: adding an oxidizing agent to a recycling stream of lithium iron phosphate (LiFePO 4 ) batteries to form a leach solution; filtering the leach solution to remove a residue and obtain a lithium rich solution; modifying pH of the lithium rich solution for filtering impurities and obtaining a purified Li solution; and adding a precipitant to the purified Li solution thereby precipitating a lithium compound.
1. A method for recycling lithium iron phosphate batteries, the method comprising:
shredding a recycling stream of lithium iron phosphate batteries to obtain granular powder comprising cathodes and anodes of batteries including lithium iron phosphate;
adding an oxidizing agent to the granular powder from the recycling stream of lithium iron phosphate (LiFePO 4 ) batteries to form a leach solution;
filtering the leach solution to remove a residue including FePO 4 and graphite and obtain a lithium rich solution;
modifying pH of the lithium rich solution for filtering impurities and obtaining a purified Li solution;
adding a precipitant to the purified Li solution thereby precipitating a lithium compound; and
after filtering, purifying the graphite by at least one process selected from acid leaching and froth flotation.
2. The method according to claim 1 , wherein prior to filtering further comprising heating the leach solution to a temperature in a range between 20° C. to 100° C.
3. The method according to claim 1 , wherein the residue comprises at least one of: graphite and FePO 4 .
4. The method according to claim 1 , wherein modifying the pH of the lithium rich solution further comprises adding a basic solution.
5. The method according to claim 4 , wherein the lithium rich solution is modified to attain the pH in a range between 5 to 13.
6. The method according to claim 1 further comprising achieving a concentration of 0.3-3.0 M of the oxidizing agent to a concentration of the LiFePO 4 .
7. The method according to claim 1 further comprising achieving a concentration of 0.5-2.2M of the oxidizing agent to a concentration of the LiFePO 4 .
8. The method according to claim 1 , wherein adding an oxidizing agent further comprises adding an acid solution.
9. The method according to claim 8 , wherein the acid solution is selected from an inorganic acid or an organic acid.
10. The method according to claim 9 , wherein the inorganic acid is at least one selected from: sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid.
11. The method according to claim 9 , wherein the organic acid is at least one selected from: acetic acid, formic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, and adipic acid.
12. The method according to claim 1 , wherein the precipitant is at least one selected from: sodium carbonate, sodium phosphate, phosphoric acid, oxalic acid, and sodium oxalate.
13. The method according to claim 1 , wherein the lithium compound is at least one selected from lithium carbonate (Li 2 CO 3 ), lithium phosphate (Li 3 PO 4 ), and lithium oxalate (Li 2 C 2 O 4 ).
14. The method according to claim 1 further comprising maintaining pH of the leach solution in a range between 1-6.
15. The method according to claim 1 , wherein the oxidizing agent is at least one selected from: a peroxide (O 2 2− ), a persulfate (S 2 O 8 2− ), a sulfate (SO 4 2 —), a hypoclorite (ClO − ), a chlorite (ClO 2 − ), a chlorate (ClO 3 − ), a perchlorate (ClO 4 − ), a nitrate (NO 3 − ), a nitrous oxide (N 2 O), a nitrogen dioxide (NO 2 ), and a halogen.
16. The method according to claim 1 , wherein the oxidizing agent is at least one selected from: hydrogen peroxide, sodium persulfate, and ammonium persulfate.
17. The method of claim 1 wherein the lithium products are lithium phosphate or lithium oxalate.
18. The method of claim 1 wherein the impurities are other than Ni, Mn and Co.
19. The method of claim 1 wherein the recycling stream includes cathode materials and anode materials, the lithium iron phosphate included in the cathode materials.
20. The method of claim 1 further comprising modifying pH of the lithium rich solution by raising the pH to 11-13 for filtering impurities.
21. A method for recycling lithium iron phosphate batteries, the method comprising:
shredding the lithium iron phosphate batteries to obtain a recycling stream of a granular powder comprising cathodes and anodes and including lithium iron phosphate;
adding at least one of: an oxidizing agent, and an acid, to the granular powder of lithium iron phosphate (LiFePO 4 ) batteries to form a leach solution;
maintaining the temperature of the leach solution from 20° C. to 100° C.;
filtering the leach solution to remove graphite and FePO 4 to obtain a lithium rich solution;
modifying pH of the lithium rich solution from 11 to 13 for filtering impurities and obtaining a purified Li solution;
adding a precipitant to the purified Li solution thereby precipitating a lithium compound; and
after filtering, purifying the graphite by at least one process selected from acid leaching and froth flotation.
22. A method for recycling lithium iron phosphate batteries, the method comprising:
shredding a recycling stream of lithium iron phosphate batteries to obtain granular powder comprising cathodes and anodes of the batteries including lithium iron phosphate;
adding an acid to the recycling stream of powdered lithium iron phosphate (LiFePO 4 ) batteries to form a leach solution;
maintaining the temperature of the leach solution from 20° C. to 100° C.;
filtering the leach solution to remove graphite and FePO 4 to obtain a lithium rich solution;
modifying pH of the lithium rich solution from 11 to 13 for filtering impurities and obtaining a purified Li solution;
adding a precipitant to the purified Li solution thereby precipitating a lithium compound; and
after filtering, purifying the graphite by at least one process selected from acid leaching and froth flotation.