Progress towards a process for the recycling of nickel metal hydride electric cells using a deep eutectic solvent

Solvent extraction experiments relating to the recycling of the transition metals and lanthanides in nickel metal hydride cells are presented. The metal extraction is occurring from a deep eutectic solvent which is formed from chemicals suitable for use in food and related products. While it has been shown that the water content of the DES has a large effect on the extraction of transition metals by a mixture of chloride ionic liquid (Aliquat 336) and an aromatic solvent, the water content has a smaller effect on the solvent extraction of lanthanides with a solution of di(2-ethylhexyl) hydrogen phosphate (DEHPA) in a saturated aliphatic hydrocarbon. This study suggests that an industrial scale solvent extraction process for the recycling of metals from nickel hydride electrical cells will be feasible.