A device (1) for comminuting and drying waste materials, slags, rocks and similar materials (M) is described, which comprises a substantially funnel-shaped tank (2) with a cylindrical attachment (4). On the cylindrical attachment (4) there are arranged at least two air inlets (5) which are distributed over the circumference and which serve for the introduction of compressed and possibly heated air (L). The base of the funnel-shaped tank is equipped with an outlet opening (3) for comminuted material (G). At that end of the tank which is situated opposite the outlet opening (3) and which is of relatively large diameter, an air outlet opening (7) is arranged on the cylindrical attachment (4). A feed device (9) for the material (M) for comminution opens into the cylindrical attachment (4). At the at least two air inlets (5) which are distributed over the circumference of the cylindrical attachment, there is arranged in each case one supersonic nozzle (10) with Venturi function, such that the fed air (L) can be introduced in a circumferential direction of the cylindrical attachment (4) and of the funnel-shaped tank (2).