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Sulphide precipitation

  • Responsible partner: VTT
  • Location of pilot: Bioruukki, Ruukinmestarintie 2, 02330 Espoo (Finland)
  • TRL: 5

The pilot ‘Sulphide precipitation’ is a bench scale pilot for leaching and precipitation for multiple different kinds of input streams. It has a flexible process configuration.

The pilot setup has the following characteristics:

Picture: Reactors


  • Temperature control (T = 25-100ºC), p = atmospheric pressure
  • Titanium and acid proof steel (904L)
  • Different sizes from 1 to 100 litre (mainly 5 and 10 litre)
  • Three thickeners (á 90 litre)


  • 8 mass flow controllers to 𝑂_2, 〖𝐶𝑂〗_2, Air (data accessible)
  • 6 mass flow controllers to 〖𝑆𝑂〗_2,𝐻_2 𝑆 (data accessible)

Pumps (with adjustable flow rates)

  • 12 acid/base pumps (data accessible)
  • 12 process pumps (data accessible)

Picture: Thickener


  • 15 channels pH / ORP / temp

Solid dosing

  • Two screw feeders with changeable screw types

Particle Track&View (for one reactor at a time)

  • Particle size (Chord Length) 0.5 to 2000 µm
  • Particle shape and size- Optical resolution > 2µm with 1300 x 890 µm view area


  • ICP-OES – located next to Flexmet for rapid analytics


Picture: ICP-OES

Picture: Solid feeder and reactors

Picture: Particle Track View

Contact: pirkka.ollonqvist@vtt.fi