Centrifugation of (s) + (l)

Centrifugation can only be done with heterogeneous mixtures. Often it is chosen as a faster method than filtration. The particles with the biggest mass (that must be the solid) will precipitate at the bottom of the tube under influence of centripetal forces.

You apply this method for example when you have a suspension: a trouble mixture of (s) + (l) that could not be separated with a filter. The solid could be built up os very tiny cristals or even macromolecules.
There are methods for centrifuging (g) + (g). Gas centrifuges are applied to separate, for example, heavy Hydrogen from normal Hydrogen.