Selective Sulfation Roasting for Cobalt and Lithium Extraction from Industrial LCO-Rich Spent Black Mass

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Metals, Volume 13, issue 2
The extraction of cobalt from secondary resources has become crucial, as cobalt has been identified as a strategically important and critical raw material due to the high risks of supply chain disruptions. In this work, selective sulfation roasting was investigated as a potential recycling strategy to extract cobalt and lithium from an industrial lithium cobalt oxide (LCO)-rich black mass. Additionally, the effect of graphite on metal extraction was studied. In the first set of experiments, the sieved black mass fraction containing both cathode and anode materials was directly roasted in a predetermined composition of gas mixtures of SO2, O2, and Ar for 1 h at 850 °C. The gas composition was determined from Kellogg’s diagram to allow for the selective sulfation of Co and Li. In another set of experiments, the carbon present in the black mass was first removed by roasting the material in Ar for 2 h and then in an Ar and O2 gas mixture for five hours at 600 °C. Afterward, selective sulfation roasting was performed in mixtures of SO2, O2, and Ar gas similar to the previous set of experiments. For comparison, similar experiments were performed at 800 °C. The sulfation roasted black mass was leached in water to study the efficiency of Co extraction into the solution. Interestingly, the presence of carbon was found to be beneficial for Co extraction. The extraction efficiency for the first case (with carbon present in the raw material) was observed to be more than three times higher than in the second case (with carbon removed) for sulfation at 850 °C. The extraction efficiency and purity of the extracted Co were found to be better for higher temperature sulfation roasting conditions due to faster reaction kinetics. It was also found that almost all of the Li could be recovered while extracting Co. The maximum efficiency of the extraction was 99.51% Li and 61.21% Co for roasting under a gas flow of 10% SO2-10% O2-Ar at 850 °C for 60 min. These results suggest that Co and Li can be selectively extracted from the black mass by sulfation roasting pre-treatment followed by leaching in water. In holistic processing, the leach residue can then be further subjected to battery metal processing by state-of-the-art methods.
Funding Information: The authors are grateful to Akkuser Oy (Finland) for providing the battery scrap. The authors would like to thank Lassi Klemettinen and Anna Klemettinen for their training on working with the furnace and SEM. The authors are also grateful to the Academy of Finland for providing financial support for this project (GOVERMAT, grant 346728). This study utilized the Academy of Finland’s RawMatTERS Finland Infrastructure (RAMI), based jointly at Aalto University, GTK Espoo, and VTT Espoo. Publisher Copyright: © 2023 by the authors.
cobalt recovery, lithium-ion battery, recycling, sulfation roasting, water leaching
Other note
Biswas, J, Ulmala, S, Wan, X, Partinen, J, Lundström, M & Jokilaakso, A 2023, ' Selective Sulfation Roasting for Cobalt and Lithium Extraction from Industrial LCO-Rich Spent Black Mass ', Metals, vol. 13, no. 2, 358 .