By exploiting thermodynamic phenomena in systems with compressed gases
, the properties of products such as their morphology and the size of
particles and fibers can be tailored to industrial needs. Separation o
f complex mixtures can be accomplished. Processes that are conventiona
lly operated in a number of costly steps can be reduced to a few opera
tions. This article gives a phenomenological classification of such pr
ocesses and explains the underlying principles. Operations developed o
n a laboratory scale as well as those already established in industry
will be discussed.