A team from metals research institute SWERIM in Sweden reports on a smelting reduction process to recover cobalt, nickel, manganese and lithium simultaneously from spent Li-ion batteries. A paper on their work is published in the Journal of Power Sources.

The proposed pyrometallurgical process is believed to be economical and environment-friendly due to that: (i) the proposed process could recover Co, Ni, Mn, and Li simultaneously with high yields; (ii) the proposed process could be integrated into the existing industry infrastructure (such as AC arc furnace and DC arc furnace), and this means a very big capital saving for the recyclers; (iii) the proposed process could be integrated with green and cheap electricity, as it is the case for Sweden.

—Hu et al.

Results from the laboratory-scale smelting reduction (carried out at 1550 ◦C in an Ar atmosphere in a vertical furnace) of chemical-grade LiCoO₂ without and with the presence of halides (CaF₂ and CaCl₂) indicated that component Co₂O₃ in LiCoO₂ could be reduced to Co metal.

Meanwhile, component Li₂O in LiCoO₂ could be reduced to lithium metal vapor or converted into volatile lithium halides (LiF and LiCl) and subsequently be recovered in the flue dust.

The researchers said that the results from smelting reduction of electrode materials of spent LIBs indicate that the electrode materials could be smelted into Co–Ni–Mn alloys, and simultaneously lithium can get concentrated and recovered in the flue dust as Li₂CO₃ and LiF.

The absence of a slag allows a nearly 100% recovery of Co, Ni, and Mn in the formed alloy and a nearly 100% recovery of lithium in the flue dust.

This paper provides technical information for developing a pyrometallurgical-dominant process to recover Co, Ni, Mn, and Li from electrode materials of LIBs. Yet, the scales of the carried-out trials are rather small, and the obtained results are limited to the laboratory findings. Further, no slag-forming materials are added during the smelting reduction process. This is substantially different from an industrial smelting reduction process, in which a slag phase is present to prevent the oxidation of molten alloy and for refining purposes. The presence of slag may retain some Co, Ni, Mn, and Li in the slag due to the inherent nature of the slag. To provide a better reference for the industrial implementation, the proposed smelting process needs to be demonstrated on a pilot scale. The results from a pilot-scale demonstration in an electric arc furnace are presented in a consecutive paper (Part II).

—Hu et al.

Resources

• Xianfeng Hu, Elsayed Mousa, Yang Tian, Guozhu Ye (2020) “Recovery of Co, Ni, Mn, and Li from Li-ion batteries by smelting reduction - Part I: A laboratory-scale study,” Journal of Power Sources doi: 10.1016/j.jpowsour.2020.228936