A device for processing feedstock, includes a housing surrounding a processing chamber in which a rotational rotor having processing tools and mounted on a drive shaft is disposed around an axis. The feedstock is fed to the processing chamber via a material inlet and removed from the device via a material outlet. To facilitate assembly and disassembly of the device and to retool, maintain and repair or clean the device, it is provided according to the invention that the housing includes a first end wall, a material element in the shape of a hollow cylinder or hollow truncated cone, and a second end wall which are detachably connected to each other to form the processing chamber. The connection can be made by axially acting clamps, which clamp the first end wall against the second end wall by clamping the casing element.