flow path 115 may be defined by any of a number of types of ducting which confines and directs a flowing stream of air the coarse particles are air conveyed along the flow path 115 to a cyclone separator 116 which separates the coarse particles from the flowing air and causes the exhaust air to pass along a flow path 117 in the preferred embodiment the flow path 117 directs the exhaust air from the cyclone separator 116 through a filter apparatus 148 to remove any remaining fine fibers and dust an auxiliary fan 146 may also be provided in the flow path 117 to provide sufficient exhaust air velocity along the flow path 117 the coarse particles introduced into the cyclone separator 116 are collected in a paper bin 118 which includes an adjustable speed screw feeder 122 for feeding the coarse paper particles from the bottom of the paper bin 118 to a second hammermill 126 the screw feeder 122 is also provided with an adjustable speed drive motor 120 which may be externally adjusted to vary the rate at which the coarse paper particles are withdrawn from the paper bin 118 part of the air from the first cyclone separator 116 flowing along the flow path 117 is channeled along a third flow path 127 in which a damper 129 is placed to regulate the air flow and then into the hammermill 126 to provide a source of heated air to assist in the drying process after the cellulose.