Process for the recovery of cathode materials in the recycling of batteries by removing aluminum and iron
A process for removal of aluminium and iron in the recycling of rechargeable batteries comprising providing a leachate from black mass, adding phosphoric acid (H 3 PO 4 ) to said leachate and adjusting the pH to form iron phosphate (FePO 4 ) and aluminium phosphate (AlPO 4 ), precipitating and removing the formed FePO 4 and AlPO 4 , and forming a filtrate for further recovery of cathode metals, mainly NMC-metals and lithium.
1. A process for removal of aluminum and iron from black mass in the recycling of rechargeable batteries, the aluminum being removed in the form of aluminum phosphate (AlPO 4 ) and the iron being removed in the form of iron phosphate (FePO 4 ), said process comprising:
providing a leachate from black mass,
adding phosphoric acid (H 3 PO 4 ) to the provided leachate,
adjusting the pH of the H 3 PO 4 containing leachate to form the (FePO 4 ) and the (AlPO 4 ,
precipitating and removing the formed FePO 4 and AlPO 4 from the pH adjusted H 3 PO 4 containing leachate, and
forming a filtrate for recovery of cathode metals.
2. The process according to claim 1 , wherein the rechargeable batteries are rechargeable lithium ion batteries.
3. The process according to claim 1 , wherein the precipitation is performed in two steps at different pH levels.
4. The process according to claim 3 , wherein the pH in a first precipitation step is adjusted to an interval of pH 1.5 to 4.
5. The process according to claim 4 , wherein the interval of pH is either: 1.5 to 3.5 or 1.5 to 3.
6. The process according to claim 3 , wherein the pH, in a second step, is adjusted to an interval of pH 2.5 to 6.5.
7. The process according to claim 6 , wherein the interval of pH is either: 2.5 to 6 or 2.5 to 4.
8. The process according to claim 3 , wherein crystallization seeds are added to precipitate FePO 4 and AlPO 4 in the first precipitation step.
9. The process according to claim 8 , wherein the crystallization seeds comprise aluminum and iron phosphate crystals and wherein said seeds are added in an amount of 0.05-0.3 g/L.
10. The process according to claim 9 , wherein the amount of added seeds is either 0.05-0.2 g/L or 0.05-0.15 g/L.
11. The process according to claim 3 , wherein the two precipitation steps are conducted at a temperature in an interval of 20-95° C.
12. The process according to claim 11 , wherein the temperature interval is either: 55-85° C. or 65-75° C.
13. The process according to claim 3 , wherein each of the two precipitation steps has a residence time in an interval of 2-24 hours.
14. The process according to claim 3 , wherein the residence time interval is one of: 12-18 h, 2-12 h, or 2-6 hours.
15. The process according to claim 3 , wherein a higher amount of FePO 4 and AlPO 4 is precipitated in a first precipitation step than in a second precipitation step.
16. The process according to claim 1 , wherein the precipitate comprising FePO 4 and AlPO 4 is washed with an aqueous solution having a pH in an interval of pH 1.5-5.5.
17. The process according to claim 1 , wherein the aqueous solution pH interval is 1.5-2.5.
18. The process according to claim 1 , wherein the filtrate comprises:
lithium, nickel, manganese and cobalt, and
less than 10 ppm of one or more of aluminum, iron, or copper.
19. The process according to claim 1 , wherein the leachate provided from the black mass is substantially copper free.
20. The process according to claim 1 , wherein copper is recovered subsequently to the removal of the aluminum in the form of the AlPO 4 and the iron in the form of the FePO 4 .