Solvent extraction

Example

See it in the plant

1. Mix and settle: 5544 kg of solution meets an organic extractant in each mixer; in the settler the two liquids separate by density.
2. Extract in turn: at a controlled pH the first stage loads manganese, the second stage loads cobalt and the third stage loads nickel into the organic; the other metals stay in the water.
3. Strip and crystallise: sulfuric acid takes each metal back out of the organic, and crystallisers make MnSO₄ 900 kg, CoSO₄ 986 kg, NiSO₄ 2945 kg.
4. Pass on: lithium stays in the water. 586 kg of raffinate goes to lithium recovery and 127 kg is bled off to stop sodium and sulfate building up.

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.

Crystallisation

Evaporating a purified solution until a battery-grade salt crystallises out — nickel sulfate, cobalt sulfate, lithium hydroxide — ready to be sold back to precursor and cathode plants.

Hydrometallurgy

Recycling by dissolving black mass in acid and separating the metals as salts by precipitation and solvent extraction. It recovers lithium and gives battery-grade products, at the cost of chemical consumption and wastewater.

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.

Mixer-settler

The working unit of solvent extraction: a chamber where the aqueous solution and the organic extractant are stirred together, and a settler where they separate again by density. Plants run banks of them in series, one bank per metal, with more for stripping the metal back out of the organic.

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.

Raffinate

The aqueous solution left after solvent extraction has taken out the target metals. In battery recycling it carries the lithium, which is recovered from it last by evaporation and precipitation.

References & further reading

Technical references

1. Recycling lithium-ion batteries from electric vehicles

   Gavin Harper et al. · Nature · 2019

   Technical reference · Reuse, disassembly and mechanical, hydro-, pyro- and direct recycling routes.

Further reading on this topic

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

2. Lithium-Ion Battery Recycling

   U.S. Environmental Protection Agency

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