A suspension is an immiscible (heterogeneous) mixture of substances consisting of a liquid and a solid floating in it. This is distributed in the liquid or is slurried up.
That is, a suspension is a disperse solid phase in a continuous liquid phase. A suspension in water is called a slurry in materials science or in natural occurrences.
sedimentation
If you let a suspension sit, unlike a solution, if its particle size is large enough, the solid will slowly sink to the bottom as a sediment.
In order to slow down this process, attempts are often made to add so-called thixotropic agents. To then separate the solid from the liquid, all you have to do is pour off the liquid (decant).
If the particle size of the solids is very small, you can speed up the sedimentation process by using centrifugation. The smaller the particles, the slower the sedimentation.
Examples of suspensions
Below we have listed some examples of suspensions:
- Slurries of sand in seawater, suspended matter or quicksand
- Concrete or mortar → mineral suspensions
- Wall paints, Indian ink → pigment suspensions (unlike dyes that go into solution)
- The light-sensitive photographic layer on film or photographic paper
The most important things about the suspension at a glance!
- A suspension is a mixture of liquid in which small solid particles are floating freely.
- When the mixture stands still, the solid sediments: it sinks to the bottom.