Abstract: A processor for use with a mixer, which includes a processor frame, mounted to the mixer tub, and a plurality of rotatable shafts, rotatably mounted to the processor frame. A plurality of processing elements is affixed to each of the rotatable shafts. A prime mover is connected to and drives at least one of the rotatable shafts, and at least one other rotatable shaft is rotated by being connected to the first rotatable shaft connected to the prime mover. Some of the processing elements on adjacent rotatable shafts overlap, and others do not. A structure may be provided to control the amount of contact between the processing elements and a material to be processed, which may include a grating above the rotatable shafts, and apparatus for raising and lowering the grating with respect to the processing elements.