Abstract: A pulverizing apparatus including a stator and a rotor, the rotor including a plurality of concentric rows of stairstep-like movable teeth which intermesh with a plurality of concentric rows of similar stairstep-like fixed teeth on the stator. Each tooth in the rows of intermeshing teeth defines a plurality of edges which extend across the direction of movement of the movable plate, thereby defining a plurality of openings between the fixed teeth and the movable teeth which vary in size and shape as the movable teeth move relative to the fixed teeth, to break down substances introduced into the openings. The apparatus is suitable for comminuting organic waste such as food waste, as well as inorganic material such as metal ore.