Brittle materials may have varying degrees of harness and are most easily processed using impact size reduction processes.
Planetary Ball Mill
This type of mill is effective for most material types. A planetary ball mill consists of at least one grinding jar arranged eccentrically on a wheel that spins in the opposite direction to the grinding jar(s). This releases high dynamic energies resulting in a fine grinding of the sample.
This type of mill is ideal for ambient and cryogenic grinding of biological samples, plant material, plastics, pharmaceuticals and chemicals. Mixer mills grind samples by imparting motion to the container in which grinding elements have been placed. As the container is rolled, swung, vibrated or shaken, the inertia of the grinding elements causes them to move independently into each other and against the container wall, grinding the sample.
Jet pulverizers utilize multiple jets of air or steam to drive the process material at near sonic velocities around the perimeter of the mixing chamber. No grinding media is involved, instead size reduction is the result of high-velocity colisions between particles of the process material itself.
A disc mill can be used to grind, cut, shear, shred, fiberize, pulverize, granulate, crack, rub, curl, fluff, twist, hull, blend or refine. Substances are crushed between opposing discs or plates, which may be grooved, serrated or spiked.
A jaw crusher consists of a set of vertical jaws, one of which is moved back and forth against the other. The jaws are farther apart at the top than at the bottom, forming a tapered chute so that the material is crushed into progressively smaller fragments as it travels downward, until it is small enough to fall through the opening at the bottom.