Process for smelting lithium-ion batteries
The invention concerns a process for the separation of cobalt from lithium present in a charge comprising lithium-ion batteries or related products, comprising the steps of: smelting the charge using a bath furnace equipped with a submerged air-fed plasma torch for injecting plasma gas into the melt; defining and maintaining a bath redox potential where cobalt is reduced to the metallic state and reporting to an alloy phase, and whereby lithium is oxidized as Li 2 O and reporting to the slag phase; decanting and separating the phases. It is characterized in that the reduction and oxidizing steps are performed simultaneously. A suitably low cobalt concentration is obtained in the slag.
1. A process for separating cobalt from lithium present in a charge comprising lithium-ion batteries or battery scrap, comprising:
smelting the charge using a bath furnace comprising a submerged plasma torch for injecting an oxygen-bearing plasma gas into the melt;
defining and maintaining a bath oxygen partial pressure whereby cobalt is reduced to the metallic state and reporting to an alloy phase, and whereby lithium is oxidized and reporting to a slag phase; and
decanting and separating the alloy phase and the slag phase;
wherein the reduction and oxidizing steps are performed simultaneously.
2. The process according to claim 1 , wherein said bath furnace further comprises a submerged injector for injecting an O2-bearing gas into the melt.
3. The process according to claim 1 , further comprising adjusting electric power to the plasma torch to maintain a target bath temperature of between 1450 and 1650° C.
4. The process according to claim 1 , further comprising adjusting oxygen input to the melt to maintain a target bath oxygen partial pressure between 10-18 and 10-14 atm.
5. The process according to claim 1 , wherein the lithium-ion batteries or their scrap represent more than 80% of the total metallurgical charge, slag formers excluded.
6. The process according to claim 1 , wherein a residual cobalt concentration in the slag phase is less than approximately 0.1% of a total mass of the slag phase.
7. The process according to claim 1 , wherein injecting the oxygen-bearing plasma gas into the melt comprises supplying heat through the oxygen-bearing plasma gas.