Separation of lithium, cobalt and nickel from spent lithium-ion batteries using TBP and imidazolium-based ionic liquids

Guillaume Zante (1) , Abderrazak Masmoudi (1) , Rémi Barillon (1) , Dominique Trebouet (2) , Maria Yu Boltoeva (1)

1 DRS-IPHC - Département Recherches Subatomiques
2 DSA-IPHC - Département Sciences Analytiques et Interactions Ioniques et Biomoléculaires

Solvent extraction of lithium ions from sulfuric acid solutions was investigated using imidazolium-based ionic liquids as diluents and tri-n-butyl phosphate as specific ligand. Aqueous phases used were simulating leach liquors of spent lithium-ion batteries, with lithium, cobalt and nickel ions in acidic solutions. A low acidity and a large amount of extractant can ensure high extraction efficiency. But the better selectivity for the lithium ions over the transition metals is obtained using a low amount of extractant and a low pH (pH < 3). The extraction of the lithium ions occurs by cation exchange with the ionic liquid cations. A sacrificial cation was introduced in the organic phase to prevent the losses, but the cation exchange is only reduced by 20%. The increase of the ionic liquid cation alkyl chain length can presumably suppress the cation exchange mechanism, reducing substantially the losses. But the addition of a lipophilic counter-anion in the organic phase is needed to ensure a mechanism of ion pairing with the lithium ion in the organic phase. Using the 1-decyl 3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid associated to tri-butyl phosphate, a satisfying extraction efficiency is obtained for the lithium ion, together with a sufficient selectivity among the transition metal ions.

Mots clés: Ionic liquids; tri-butyl phosphate; solvent extraction; lithium recycling

Domaines: Génie chimique

Guillaume Zante, Abderrazak Masmoudi, Rémi Barillon, Dominique Trebouet, Maria Yu Boltoeva. Separation of lithium, cobalt and nickel from spent lithium-ion batteries using TBP and imidazolium-based ionic liquids. Journal of Industrial and Engineering Chemistry, 2020, 82, pp.269-277. ⟨10.1016/j.jiec.2019.10.023⟩. ⟨hal-02492907⟩