Multistage hammer mill and a residue processing system incorporating same

A mill for devitalising weed seeds comprising:

• a rotary impact mechanism capable of rotating about a rotation axis, the impact mechanism being arranged to impact material entering the mill and accelerate the impacted material in a radial outwards direction, the rotary impact mechanism comprising a hub that rotates about the rotation axis and a plurality of flails, wherein each flail is pivotally coupled by a respective pin to the hub, each pin being parallel to and radially spaced from the rotation axis wherein each flail is capable of pivoting about a corresponding respective pin and rotating about the rotation axis;
• at least a first circular array of impact elements disposed circumferentially about and radially spaced from the rotary impact mechanism, at least one impact element being elongated and extending in a direction parallel to the rotation axis;
• a second circular array of impact elements disposed circumferentially about and radially spaced from the first circular array, at least one impact element of the second circular array being elongated and extending in a direction parallel to the rotation axis;
• a base plate to which the rotary impact mechanism and the at least first circular array and the second circular array of impact elements are attached;
• wherein the second circular array of impact elements includes a second ring to which an upper end of each impact element is attached;
• and
• at least one scraper on an upper surface of the second ring.