Drum dryers for simultaneous product cleaning have an area in the inside of the dryer in which the solid material is rubbed against itself to an increasing extent.
DRYING AND CLEANING
DRYING and cleaning of the contaminated stone takes place in two combined zones of the dry cleaning drum. First of all, the stone is dried very quickly in the rotary drum using hot gas. Following this, it is cleaned by intensive mixing which causes the stones to rub together in the extended cleaning zone. Adhering mud or clay is removed from the stone by the combination of thermal and mechanical processes, and the impurities are comminuted, dried further and finally converted into dust. The dust is removed by the waste air from the dryer to be collected in the waste air filter or by a screening machine. The result is cleaned and dry limestone comparable with the quality of a washing system.