We focus on the purification of dusts to recover valuable materials using electrokinetic processes. In particular, we target the recovery of precious metals from dust fractions generated during the recycling of waste electrical and electronic equipment (WEEE). To this end, we use dielectrophoresis, a technique capable of sorting micro- and submicrometer particles according to their size, shape, and material properties. One application example is the separation of black mass, an intermediate product formed during the recycling of lithium‑ion batteries. Black mass is typically refined by hydrometallurgical processes, which require large amounts of acidic solutions and generate significant volumes of acidic wastewater; moreover, the anode material graphite – classified as a critical raw material in the EU – is usually not recovered in these process chains.

Dielectrophoresis enables a purely mechanical separation of black mass into two fractions: one enriched in cathode material and one enriched in anode material. Such a pre‑sorting step allows a substantial reduction in acid consumption (and thus wastewater generation), can in principle lead to higher overall recycling rates, and opens up the possibility to mechanically recover and reuse graphite. We have recently demonstrated the feasibility of such a separation for lithium iron phosphate and graphite.

doi.org/10.1021/acsomega.3c04057

doi.org/10.1016/j.rineng.2024.101854