Separation process

A separation process takes advantage of the different physical and chemical properties of the intermixed substances to separate them from each other. The separation of mixtures of substances is one of the most important basic engineering operations. Most raw materials and products from chemical reactions are mixtures of substances. They must be separated for further processing. Also, sewage treatment and sorting of recyclable materials from light and composite packagings ( yellow bag ) are among the separation process. In metallurgy, the separation of materials of the present as a melt metals under the technical term is summarized purification.

  • 2.1 separation due to the surface wettability
  • 2.2 separation due to the density
  • 2.3 separation due to the particle size
  • 2.4 separation due to the particle inertia
  • 2.5 separation due to the magnetization
  • 2.6 separation due to the electrical mobility

Thermal separation processes

Thermal separation processes are all separation methods based on the setting of a thermodynamic phase equilibrium. There are essentially three different separation processes.

Separation due to the boiling point

  • The dual-pressure process
  • The extractive
  • Azeotropic rectification.

Separation due to the freezing

Separation by sublimation

Separation due to the solubility

Solubility is a chemical property that is sometimes associated with further separation effects.

  • Chromatography, this other phenomena such as the adsorption of the separation effect is in addition to the solubility involved.
  • Washing
  • When extracting a distribution equilibrium between two phases is established. Here, the value of an entrainer substance which solves the recycling well, but none of the other possible additives, is extracted from a mixture. The recyclables must be separated from the entrainer then. In addition to this liquid-liquid extraction, it is also Pervaporation ( continuous extraction )
  • Solid phase extraction

Mechanical separation processes

The mechanical separation process make use of differences in the mechanical properties of the ingredients. This can also be visual differences.

  • Pick out
  • Sorting
  • Truncation

Separation due to the surface wettability

  • Flotation is a separation method in which finely granular solid mixture in an aqueous slurry (suspension) with the aid of air bubbles are separated due to the different surface wettability of the particles.

Separation due to the density

Density differences of substance mixtures can be used in the following methods.

  • Sedimentation, decantation and separation
  • Centrifugation
  • Dense medium separation
  • Slurry is a mechanical separation methods for the quantitative determination of the fine particle fraction of a sediment sample ( Dispersitätsanalyse ).

Separation due to the particle size

  • Filtration, in particular the so-called suction filtration with vacuum
  • Rake
  • Seven is a mechanical separation process for size separation ( classification ) of bulk materials.
  • Surveys carried out by plansifter or winnowing
  • Membrane separation process
  • Reverse osmosis

Separation due to the particle inertia

When using the particle inertia of movements can be used for the separation.

  • Centrifugal ( cyclone)
  • Impactor
  • Strahlumlenksichter

Separation due to the magnetization

The magnetic material properties, the magnetization is utilized.

  • Magnetic separation
  • Eddy current separation

Separation due to the electrical mobility

  • Electrostatic precipitator

Separation as a result of chemical reactions

By the sequence of reactions, the physical properties are changed, which in turn can be used for separation.

  • Etching with nitric acid ( aqua fortis )
  • Electrolysis is a process in which the electric current will force a chemical reaction.
  • Electrophoresis gel electrophoresis

In zone melting process for obtaining highly pure single crystals or metals is exploited that impurities in the melt an energetically more favorable chemical environment (lower chemical potential ) than in the solid state and therefore migrate from the solid into the melt.

Chemistry Azeotrope Extractive distillation Desorption Countercurrent exchange Phase (matter) Flotation process Büchner funnel Cupellation DECHEMA Integrated Authority File
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