Density separation

Example

See it in the plant

1. Shred under nitrogen: 30.38 t of cells are cut by two counter-rotating knife shafts in a nitrogen-filled chamber, so the electrolyte vapour cannot ignite.
2. Dry: the shredded material is heated and held under vacuum. 2700 kg leaves as volatiles: solvents to gas treatment.
3. Screen: the vibrating screen lets the fine coating powder fall through its mesh. 13.18 t of black mass carries 92% of the lithium, nickel, cobalt and manganese.
4. Classify: the coarse pieces meet an upward air stream in a zig-zag channel. Heavy copper foil falls (3342 kg), aluminium foil leaves in the middle (6178 kg) and light plastics fly over the top (2755 kg).
5. Catch: the cyclone and filters take the dust out of the air: 2227 kg of fines, counted as a loss.

Use in Lemonergy

Distinguish recovered material from a qualified product.

This is a reference concept. No executable Lemonergy block has been verified for this term.

Connected concepts

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Cyclone separator

A cone in which a gas stream spins fast enough to throw dust against the wall, where it slides down and is collected. In mechanical pre-treatment it recovers fine black mass from the air used to dry and convey shredded cells.

Eddy-current separation

Ejecting non-ferrous metals such as aluminium from a moving stream with a rapidly rotating magnetic field, which induces currents in conductive pieces and throws them off the belt. It recovers casing and foil aluminium.

Mechanical pre-treatment

The front end of most recycling plants: shredding cells or modules, drying off the electrolyte and separating the stream into casings, copper and aluminium foil, plastics and black mass. How cleanly this is done sets the purity, and the cost, of everything downstream.

Sieving and classification

Splitting shredded material by particle size: the fine fraction is mostly black mass, the coarse fractions mostly foil, casing and separator. Air classifiers do the same by size and density in a gas stream.

References & further reading

Further reading on this topic

These sources provide broader context; they are not presented as citations for every statement in this entry.

1. Lithium-Ion Battery Recycling

   U.S. Environmental Protection Agency

   Topic background · Battery construction, recycling routes and U.S. waste-management context.

2. Recycling lithium-ion batteries from electric vehicles

   Gavin Harper et al. · Nature · 2019

   Topic background · Reuse, disassembly and mechanical, hydro-, pyro- and direct recycling routes.