Aimed principally at increasing the impact velocity of the particle assuming a given circumferential velocity and to achieve collinear collision of particles by a mechanical method with a consideration on energy saving for comminution, a prototype dual cone impact mill was designed and built. This dual cone impact mill mainly consists of two cone disks with the same geometrical dimensions, and the same rotational speeds rotating in opposite directions. There are no grinding media in the dual cone impact mill. The dependence of the comminution effect on two parameters, cone disk speed and air flow rate, was experimentally investigated. The results obtained from grinding quartz and cement clinker indicate that this prototype mill can be used for grinding materials of Mohs hardness up to of 6-7, while achieving mean particle sizes of 10 m.