Comminution

Comminution is the process in which solid materials are reduced in size, by crushing, grinding and other processes.^[1][2] It occurs naturally during faulting in the upper part of the crust^[3] and is an important operation in mineral processing, ceramics, electronics and other fields. Within industrial uses, the purpose of comminution is to reduce the size and to increase the surface area of solids. It is also used to free useful materials from matrix materials in which they are embedded, and to concentrate minerals.^[2]

Comminution energy

The comminution of solid materials consumes energy, which is being used to break up the solid into smaller pieces. The comminution energy can be estimated by:

• Rittinger's law, which assumes that the energy consumed is proportional to the newly generated surface area;
• Kick's law, which related the energy to the sizes of the feed particles and the product particles;
• Bond's law, which assumes that the total work useful in breakage is inversely proportional to the square root of the diameter of the product particles, [implying] theoretically that the work input varies as the length of the new cracks made in breakage.^[4]
• Holmes's law, which modifies Bond's law by substituting the square root with an exponent that depends on the material.^[2]

Methods of Comminution

There are several manual methods of comminution. Trituration, for instance, is comminution (or substance breakdown) by rubbing. Trituration can further be described as levigation, trituration of a powder with an insoluble liquid, or pulverization by intervention, which is trituration with a solvent that can be easily removed after the substance has been broken down.

See also

• Mill (grinding)

References