Recovery of nickel and cobalt from black mass
The present invention lies in the field of pyrometallurgy and discloses a process and a slag suitable for the recovery of Ni and Co from Li-ion batteries or their waste, particularly from Black Mass. The slag composition is defined according to: 25%<MnO<70%; Al 2 O 3 +0.5 MnO<45% SiO 2 >5%; Li 2 O>1%; MnO+Li 2 O+Al 2 O 3 +CaO+SiO 2 +FeO+MgO+P 2 O 5 >90%; and, wherein (CaO+2 Li 2 O+0.4 MnO)/SiO 2 ≥2.0. This composition is particularly adapted to limit or avoid the wear or corrosion of furnaces lined with magnesia-bearing refractory bricks.
1. Process for the recovery of Ni and Co from Li-ion batteries or their waste, comprising the steps:
providing a furnace lined with magnesia-bearing refractory bricks;
providing a charge comprising slag formers and Li-ion batteries or their waste, wherein the content of Al in the charge is less than 8%; and,
smelting the charge in reducing conditions, thereby obtaining an alloy containing the major part of the Ni and Co, and a Li-containing slag, wherein the slag has a percent composition by weight according to:
25%<MnO<70%;
Al 2 O 3 +0.5 MnO<45%
SiO 2 >5%;
Li 2 O>1%;
MnO+Li 2 O+Al 2 O 3 +CaO+SiO 2 +FeO+MgO+P 2 O 5 >90%; and,
wherein (CaO+2 Li 2 O+0.4 MnO)/SiO 2 ≥2.0.
2. Process according to claim 1 , wherein the content of MnO in the slag is 30% or more.
3. Process according to claim 1 or 2 , wherein the content of Al 2 O 3 in the slag is less than 30%.
4. Process according to claim 1 , wherein Al 2 O 3 +0.5 MnO<30%.
5. Process according to claim 1 , wherein the Li-ion batteries or their waste is Black Mass.
6. Process according to claim 1 , wherein the content of CaO in the slag is 40% or less.
7. Process according to claim 1 , wherein the slag formers contain no CaO.
8. Process according to claim 1 , wherein the content of Li 2 O in the slag is 3% or more.
9. Process according to claim 1 , wherein the content of cobalt oxide in the slag is 0.05%<CoO<1%.
10. Process according to claim 1 , wherein the content of Fe in the slag is 25% or less.
11. Process according to claim 1 , wherein the content of Fe in the charge is 5% or less.
12. Process according to claim 1 , wherein the content of P 2 O 5 in the slag is 0.5%<P 2 O 5 <10%.
13. Process according to claim 1 , wherein the step of smelting the charge is performed at a temperature of at least 1400° C. and at most 300° C. above the liquidus point of the slag, thereby avoiding overheating.
14. Process according to claim 1 , the smelting step comprising the further steps:
sampling the slag;
cooling down the slag sample and assessing its color; and,
in case the slag sample is green, terminating the smelting step; or,
in case the slag sample is not green, proceeding with the smelting step after adjusting the pO 2 -level to achieve more reducing conditions.
15. Process according to claim 1 , wherein the pO 2 -level is adjusted to 10 −7 >pO 2 >10 −12 .
16. Process according to claim 14 , wherein the color of the slag is green.
17. Process according to claim 1 , wherein the furnace is an electric furnace.
18. Li-containing metallurgical slag having a percent composition by weight according to:
25%<MnO<70%;
Al 2 O 3 +0.5 MnO<45%
SiO 2 >5%;
Li 2 O>3%;
MnO+Li 2 O+Al 2 O 3 +CaO+SiO 2 +FeO+MgO+P 2 O 5 >90%; and,
wherein (CaO+2 Li 2 O+0.4 MnO)/SiO 2 ≥2.0.
19. Li-containing metallurgical slag according to claim 18 , wherein the color of the slag is green.
20. Li-containing metallurgical slag according to claim 18 or 19 , wherein the content of MnO in the slag is 30% or more.
21. Li-containing metallurgical slag according to claim 18 , wherein the content of Al 2 O 3 in the slag is less than 30%.
22. Li-containing metallurgical slag according to claim 18 , wherein the content of CaO in the slag is 40% or less.
23. Li-containing metallurgical slag according to claim 18 , wherein the content of Fe in the slag is 25% or less.
24. Slag former in a pyrometallurgical recycling process comprising the Li-containing metallurgical slag according to claim 18 .
25. The process according to claim 1 , wherein the slag former comprises a Li-containing metallurgical slag having a percent composition by weight according to:
25%<MnO<70%;
Al 2 O 3 +0.5 MnO<45%
SiO 2 >5%;
Li 2 O>3%;
MnO+Li 2 O+Al 2 O 3 +CaO+SiO 2 +FeO+MgO+P 2 O 5 >90%; and,
wherein (CaO+2 Li 2 O+0.4 MnO)/SiO2≥2.0.
26. Li-containing metallurgical slag according to claim 18 , wherein the slag further contains cobalt.