Depolymerization and leachability of spent videotape for cobalt recovery
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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en
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9
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Minerals Engineering, Volume 201
Abstract
Cobalt is a widely used technology-enabling metal that is dominantly recovered as a by-product of copper and nickel. However, mainly because of its economic importance and high supply risks, it is classified as a critical raw material in Europe, increasing the importance of the utilization of secondary cobalt resources. This work presents a study of the recovery of a pure form of cobalt oxalate from spent low-grade VHS videotapes (0.35 wt% of cobalt). Firstly, depolymerization of the videotape was conducted by alkaline hydrolysis resulting in 94.5% polyethylene (PET) depolymerization yield (T = 150 °C, p = 6.9 bar, [NaOH] = 1 mol L-1). Secondly, metal-rich residue (2.3 wt% of cobalt, 54.5 wt% of iron) of alkaline hydrolysis was subjected to hydrometallurgical leaching in two acids (H2SO4 and H3PO4) at 1 M (S/L = 10 g L−1, t = 5 min, T = 80 °C). In the subsequent oxalate precipitation study, 99.9% purity and 98.0% yield of cobalt precipitate could be achieved. This study provides insight into the technical feasibility of the combined alkaline hydrolysis and hydrometallurgical recovery of cobalt from secondary videotape resources.Description
The authors thank the European Regional Development Fund 2014−2020 (project code A74334), Academy of Finland (no. 330076, 336423, and 325002), Emil Aaltonen Foundation project grant (no. 180288), and Business Finland BATCircle2.0 project (Grant number 44886/31/2020) for the financial support. The authors are grateful to Dr. Liisa Puro and Dr. Toni Väkiparta for their kind support during this project and help in ICP and SEM/EDX measurements.
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Makarava, I, Esmaeili, M, Pöntynen, S, Kavun, V, Bilesan, M R, Lundström, M & Repo, E 2023, 'Depolymerization and leachability of spent videotape for cobalt recovery', Minerals Engineering, vol. 201, 108181. https://doi.org/10.1016/j.mineng.2023.108181