Battery knowledge · Recycling and end of life

Bleed stream

Part of a recirculating process solution removed on purpose so that sodium, sulfate and trace impurities do not build up. Any valuable metal still dissolved in it is lost, so the bleed is a balance between purity and recovery.

Example

Recycling and end of life: an example situation

High mass recovery alone does not establish battery-grade purity or refining energy demand.

Read Bleed stream alongside Impurity removal in this context. Removing copper, iron and aluminium from the leach liquor before the valuable metals are separated, typically by cementation and by raising the pH until their hydroxides precipitate. Battery-grade products need impurities in the parts per million.

See it in the plant

How the metals are separated, as a labelled cutaway with numbered steps.
Separate metals: how the unit works. Drawn by the Lemonergy recycling study for 100 returned NMC 622 packs of 60 kWh through mechanical + hydrometallurgy. The numbers match the steps below. Redraw it for your own fleet in the recycling study ↗
  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.

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.