Rotary dryer uses lifters mounted in the shell to produce a cascade of particles falling through a hot gas stream. The mechanical lifting of the material allows rotary dryers to be used to dry materials ranging from fine filter cake to coarse minerals.

It also helps in breaking up lumps, promoting a more uniformly dried material. Rotary dryers are slightly inclined cylindrical shells supported by 2 riding rings running on a set of rollers. The kiln has a seal at both ends to prevent leakage in or out of air and material. Rotary dryers are suitable for drying a wide range of materials because of their ability to process materials having considerable variation in size and composition.