The rotary dryer is a type of industrial dryer used to reduct or minimize the moisture content of the material.

Rotary dryer is handling by bringing it into direct contact with a heated gas, or indirect contact with hot air. The rotary dryer is made up of a large,rotating cylindrical tube, usually supported by concrete columns or steel beams.

Rotary dryer slopes slightly so that the discharge end is lower than the material feed end in order to convey the material through the rotary dryer under gravity.

Material to be dried enters the dryer by belt conveyor or screw conveyor. As the dryer rotates, the material is lifted up by a series of internal flights lining the inner wall of the rotary dryer.

When the material gets high enough to roll back off the flights, it falls back dowm to the bottom of the rotary dryer, passing through the hot gas stream when it falls.

This hot gas stream can either be moving toward the discharge end from the feed end (know as co-current flow), or toward the feed end from the discharge end (known as counter-current flow).

The hot gas steram can be made up of a mixture of air and combustion gases from a burner, in which case the dryer is called a direct heated rotary dryer.