In general, liquid-liquid extraction is applied where alternative separation technologies such as distillation are uneconomical, or even unsuitable. Typical examples:

  • Simultaneous separation of various components with widely differing boiling points
  • Separation of high-boiling products or pollutants that are present in only low concentrations
  • Separation of components with similar boiling points or components forming azeotropes
  • Separation of mixtures with thermally sensitive components
  • Selective separation of single components out of a complex mixture

Our portfolio includes a complete range of liquid-liquid-extraction equipment, enabling us to provide you with the most appropriate solution for your requirements. In addition to agitated columns, it includes mixer-settlers and packed columns.


The agitated Kühni column has a simple and robust design. The drive unit and the shaft are supported at the top of the column, allowing you to use all common types of shaft seals (stuffing box, mechanical seals). In special cases, the seal can be replaced by a magnetic drive. Only radial slide-bearings are necessary inside the column, which are accessible through hand or man holes. The sturdy design, the selected materials, and the low rotational speed of industrial columns (typically 10-100 rpm) allow a practically maintenance-free operation.


  • Universal use
  • High flexibility for varying process parameters and physical properties
  • Reliable scale-up
  • More than 30 theoretical stages in one single column
  • Standard turndown 1:3
  • Diameter: 30 mm – 3.5 m
  • Physical properties Density difference > 50 kg/m3
  • Viscosity: up to 500 mPas
  • Interfacial tension: >1mN/m
  • Phase ratio up to 70:1
  • Materials Stainless steel / higher alloys