Indirectly acting drying drums are suitable for drying free-flowing bulk materials with a small particle size that may need to be intensely heated up or calcined. In addition, when it comes to drying materials containing solvents, these drums are generally preferred over direct drying methods that use hot air as a drying medium, as the drum can work with a reduced-oxygen atmosphere on the inside.
In indirect drying, the wet material is moved on one side of a partition wall while the wall is heated up from the other side. Due to the large temperature differentials, an effective transfer of heat from the hot wall to the bulk material is achieved, with the bulk material being heated up and dried as a result. The partition wall can be heated up in a variety of ways.
Ideal for: Bulk materials that are not sticky and have good flowing properties and small particle sizes, e.g., zeolite, gypsum, sodium silicate, titanium dioxide