Comminution

Source: Wikipedia, the free encyclopedia.

Comminution is the reduction of

mastication of food. In general medicine, it is one of the most traumatic forms of bone fracture
.

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]

Energy requirements

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;[4]
  • Kick's law, which related the energy to the sizes of the feed particles and the product particles;[5]
  • 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.[6][7]
  • Holmes's law, which modifies Bond's law by substituting the square root with an exponent that depends on the material.[2]

Forces

There are three forces which typically are used to effect the comminution of particles:

compression
.

Methods

There are several methods of comminution. Comminution of solid materials requires different types of

hammer crusher. Primary crusher product in intermediate feed particle size ranges (100mm > P80 > 20mm) can be ground in autogenous (AG) or semi-autogenous (SAG) mills depending on feed properties and application requirements. For comminution of finer particle size ranges (20mm > P80 > 30 μm) machines like the ball mill, vertical roller mill, hammer mill, roller press or high compression roller mill, vibration mill, jet mill and others are used. For yet finer grind sizes (sometimes referred to as "ultrafine grinding"), specialist mills such as the IsaMill
are used.

Trituration, for instance, is comminution (or substance breakdown) by rubbing. Furthermore, methods of trituration include levigation, which is trituration of a powder with a non-solvent liquid, and 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) – Device that breaks solid materials into smaller pieces by grinding, crushing, or cutting
  • Particle size distribution
     – Function representing relative sizes of particles in a system
  • Crusher – Machine designed to reduce large objects into smaller ones
  • Electromagnetic vortex intensifier with ferromagnetic particles - Special equipment for ultrafine grinding

References

  1. ISBN 9783527605255
    . Retrieved August 22, 2010.
  2. ^
    ISBN 9780080553467
    . Retrieved August 20, 2010.
  3. doi:10.1146/annurev.ea.14.050186.001053
    . Retrieved 2 July 2011.
  4. ^ Jankovic, A.; Dundar, H.; Mehta, R. (March 2010), "Relationships between comminution energy and product size for a magnetite ore" (PDF), Journal of the Southern African Institute of Mining and Metallurgy, 110: 141–146, archived from the original (PDF) on 2013-03-06, retrieved 2015-06-16.
  5. ^ Kick, F.M. Das Gesetz der proportionalen Widerstände und seine anwendung felix. Leipzig, Germany. 1885.
  6. ^ Bond, Fred C. (1975) It Happened to Me, Ch. 130. Amazon.com. Retrieved May 29, 2011.
  7. ^ Bond, F.C. The third theory of comminution.Trans. AIME, vol. 193, 1952. pp. 484–494.
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