Drying system, automatic rotation, sufficient heat exchange The drying drum welded together by steel plate. After being thrown into drying drum, the aggregate goes into the special design blade, which makes the material falling uniformly like the “aggregate curtain”, so that the aggregate can make sufficient heat exchange with the hot smoke produced by the burner. There special thermal protection blade in the flame burning zone will ensure no “aggregate curtain” in this zone, make sure the flame fully burning, and form a protection layer between the blame and the internal wall of the drying drum in order to reduce the heat loss.