The present disclosure is directed to a system and method for converting metal-containing waste wood material into livestock bedding having a reduced metal content. Waste wood, such as used or broken pallets is placed in a hammermill having a screen with holes of a larger diameter. The output of that hammermill is then placed in a hammermill having a screen with holes of a smaller diameter. A crossbelt system of magnets is passed across the waste wood to remove nails and other metal contaminates from the waste wood to produce a low metal content livestock bedding having particles of a consistent size.

An autogenous impact mill (10) is operative to size reduce friable material particles processed through operation of the mill. At least one impeller (58) rotatable within an interior area (44) of a housing (12) of the mill is operative to produce one or more air jets. The air jets are operative to suspend material particles using the Coanda Effect. Other particles moved by the air jets bounce off ricochet bars (74) and impact suspended particles so as to break and reduce the particles to a suitable size to pass through a screen (110) to an outlet opening (42).

A pin mill includes a rotor plate mounted on a shaft and having concentrically spaced-apart circular arrays of pins arise from an end face. The rotor pins interdigitate with complementary concentric arrays of pins arising from a face of a stator mounted on a door. The door swings open on a hinge mounted on two translator pins so that the door can translate the interdigitated pins before swinging open so that the pins arrays do not collide with each other while the door is opening. The rotor operates within a cylindrical screen which retains particles being broken up until they are small enough to exit. The rotor also includes a circular array of vane knives which sweep closely within the screen and also entrain cooling air into the macerating volume of the mill. Oversized particles trapped in the screen also get cleared and split apart by the passing vane knives.

A pin mill includes a rotor plate mounted on a shaft and having concentrically spaced-apart circular arrays of pins arise from an end face. The rotor pins interdigitate with complementary concentric arrays of pins arising from a face of a stator mounted on a door. The door swings open on a hinge mounted on two translator pins so that the door can translate the interdigitated pins before swinging open so that the pins arrays do not collide with each other while the door is opening. The rotor operates within a cylindrical screen which retains particles being broken up until they are small enough to exit. The rotor also includes a circular array of vane knives which sweep closely within the screen and also entrain cooling air into the macerating volume of the mill. Oversized particles trapped in the screen also get cleared and split apart by the passing vane knives.

An impact crusher for grinding and separating solid material has a base, a rotor on the base having an upright shaft defining an upright rotor axis about which the rotor is rotatable, and a drum fixed on the base, spacedly surrounding the rotor, and formed by a pair of generally semicylindrical drum shells fitted together at a plane including the rotor axis. An array of axially extending and angularly substantially equispaced replaceable ribs is provided on an inner surface of the drum. A plurality of impact hammers are angularly substantially equispaced around the rotor and orbitable past the ribs on rotation of the rotor.

An impact crusher for grinding and separating solid material has a base, a rotor on the base having an upright shaft defining an upright rotor axis about which the rotor is rotatable, and a drum fixed on the base, spacedly surrounding the rotor, and formed by a pair of generally semicylindrical drum shells fitted together at a plane including the rotor axis. An array of axially extending and angularly substantially equispaced replaceable ribs is provided on an inner surface of the drum. A plurality of impact hammers are angularly substantially equispaced around the rotor and orbitable past the ribs on rotation of the rotor.

A pin mill includes a rotor plate mounted on a shaft and having concentrically spaced-apart circular arrays of pins arise from an end face. The rotor pins interdigitate with complementary concentric arrays of pins arising from a face of a stator mounted on a door. The door swings open on a hinge mounted on two translator pins so that the door can translate the interdigitated pins before swinging open so that the pins arrays do not collide with each other while the door is opening. The rotor operates within a rotatable cylindrical screen which retains particles being broken up until they are small enough to exit. The rotor includes a circular array of vane knives which sweep closely within the screen and also entrain cooling air into the macerating volume of the mill. Oversized particles trapped in the screen also get cleared and split apart by the passing vane knives.

An impact mill (10) has an inlet (12) for material to enter the mill, an impact mechanism (16, 50) arranged to rotate about a rotation axis and being operable to pulverise the material after entering through the inlet, and an outlet (154) for discharge of pulverised material. Blockage sensors (Bj), vibration sensors V, torque sensors Tn, temperature sensors and proximity sensors may be selectively incorporated into the mill.

A method and apparatus for grinding a particulate material is disclosed. The method may include providing a system including a roller mill apparatus and a hammermill apparatus, operating the roller mill apparatus and the hammermill apparatus, adjusting a feed rate of particulate material to the roller mill apparatus until power consumption by operation of the roller mill apparatus achieves a target power consumption for the roller mill apparatus, and adjusting a gap between mill rolls of the roller mill apparatus until power consumption by operation of the hammermill apparatus achieves a target power consumption for the hammermill apparatus. The system may include roller and hammermill apparatus with sensing and controlling apparatus configured to operate the roller and hammermill apparatus according to the methods disclosed.

A method and apparatus for grinding a particulate material is disclosed. The method may include providing a system including a roller mill apparatus and a hammermill apparatus, operating the roller mill apparatus and the hammermill apparatus, adjusting a feed rate of particulate material to the roller mill apparatus until power consumption by operation of the roller mill apparatus achieves a target power consumption for the roller mill apparatus, and adjusting a gap between mill rolls of the roller mill apparatus until power consumption by operation of the hammermill apparatus achieves a target power consumption for the hammermill apparatus. The system may include roller and hammermill apparatus with sensing and controlling apparatus configured to operate the roller and hammermill apparatus according to the methods disclosed.