Liquid – Liquid Extraction Mixer-Settler

Liquid/liquid-extraction with the use of mixer settler gives the possibility for the use with discontinuous and transient flow rates. After feed interruption the concentration profile in each step is still stable.
This makes the mixer settler as ideal equipment for R&D. It is also used in production, if there is only the need for limited number of steps.

Konventioneller Mixer-Settler

The two phases are sucked into the mixing chamber, mixed intensively by the (speed-controlled) stirrer and kept in contact during the time required for the mass transfer. The settler is usually a horizontal container in which the two phases separate from each other. For the height adjustment of the phase separation layer, it has an overflow for the heavy phase, which can be adjusted during the process. The light phase occurs in the upper part of the settler.

Mixer Settler Characteristics

  • High separation efficiency of a stage
  • Flexible adaption of geometrie for different throughput- and operating conditions
  • Optimum droplet size or residence by appropriate dimensioning
  • Simple mechanical structure at relatively low height
  • Straightforward (easy) Scale-up
  • Intensitive toward suspended solids
  • Easy change of equipment in cascade installations


  • Residence time parameter

  • Reaction systems

  • Difficult coalescenece

  • pH-sensible systems

  • additional feed and off take options

  • Low number of theoretical stages