Impurity removal

Example

See it in the plant

1. Cement copper: iron powder is stirred into 6331 kg of leach solution. Copper, the more noble metal, comes out as metal powder (341 kg) while iron dissolves in its place.
2. Precipitate: alkali raises the pH until iron, aluminium and phosphate fall out as hydroxides and phosphates, while nickel, cobalt, manganese and lithium stay dissolved.
3. Press: the filter press squeezes the solids into a cake. 446 kg of Fe/Al cake leaves as a loss, carrying 1.0% of the nickel, cobalt and lithium with it.
4. Pass on: 5544 kg of clean solution goes to metal separation.

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

Related concepts from the knowledge graph. Connections show context, not cause and effect. Hover or focus a linked term for its definition.

Cementation

Removing a dissolved metal by adding a more reactive metal powder: copper comes out of the leach solution as metal while iron dissolves in its place (Cu²⁺ + Fe → Cu + Fe²⁺). It is a common first purification step in battery recycling.

Filter press

A stack of plates covered with filter cloth and clamped together hydraulically, into which a slurry is pumped: the liquid passes the cloth and the solids stay behind as a cake. Recycling plants use it after leaching, purification and precipitation.

Leaching

Dissolving the metals in black mass, usually in sulfuric acid with hydrogen peroxide as a reducing agent so cobalt and manganese go into solution as their more soluble lower oxidation state. The leach liquor carries lithium, nickel, cobalt and manganese, plus impurities such as copper and aluminium.

Precipitation

Recovering a dissolved metal as a solid by adding a reagent that makes it insoluble — nickel and cobalt as hydroxides, lithium as carbonate with sodium carbonate. Co-precipitating nickel, manganese and cobalt together gives a precursor directly.

Solvent extraction

Separating metals in the leach liquor by contacting it with an organic phase carrying an extractant that picks up one metal at a time, controlled by pH: manganese, then cobalt, then nickel, leaving lithium in the water. It is how recyclers reach battery-grade sulfates.

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.