A device (10) for mechanically comminuting material conglomerates. The device includes a comminuting chamber (14) having a feed side and an outlet side, surrounded by a chamber wall with rotors (26, 28, 30) each including a rotor shaft and striking tools (38) extending radially into the comminuting chamber. The directions of rotation of the rotors (26, 28, 30) are opposite in at least two consecutive segments. An air stream device (31, 37, 39, 41) for leading a particle/air mixture out of the comminuting chamber (14) is arranged in connection with the comminuting chamber.