Ball mill

[4] For systems with multiple components, ball milling has been shown to be effective in increasing solid-state chemical reactivity.

Ball mills rotate around a horizontal axis, partially filled with the material to be ground plus the grinding medium.

Large to medium-sized ball mills are mechanically rotated on their axis, but small ones normally consist of a cylindrical capped container that sits on two drive shafts (pulleys and belts are used to transmit rotary motion).

High-quality ball mills are potentially expensive and can grind mixture particles to as small as 5 nm, enormously increasing surface area and reaction rates.

The grinding chamber can also be filled with an inert shield gas that does not react with the material being ground, to prevent oxidation or explosive reactions that could occur with ambient air inside the mill.

Ball milling boasts several advantages over other systems: the cost of installation and grinding medium is low; the capacity and fineness can be adjusted by adjusting the diameter of the ball; it is suitable for both batch and continuous operation; it is suitable for open and closed-circuit grinding; it is applicable for materials of all degrees of hardness.

A planetary ball mill consists of at least one grinding jar which is arranged eccentrically on a so-called sun wheel.

The difference in speeds between the balls and grinding jars produces an interaction between frictional and impact forces, which releases high dynamic energies.

The interplay between these forces produces the high and very effective degree of size reduction of the planetary ball mill.