#jsDisabledContent { display:none; } My Account | Register | Help

# Comminution

Article Id: WHEBN0028439122
Reproduction Date:

 Title: Comminution Author: World Heritage Encyclopedia Language: English Subject: Collection: Publisher: World Heritage Encyclopedia Publication Date:

### Comminution

Comminution is the reduction of solid materials from one average particle size to a smaller average particle size, by crushing, grinding, and other processes.[1][2] In geology, it occurs naturally during faulting in the upper part of the Earth's crust.[3] In industry, it is an important operation in mineral processing, ceramics, electronics, and other fields. In dentistry, it is the result 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;
• Kick's law, which related the energy to the sizes of the feed particles and the product particles;[4]
• 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.[5][6]
• 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: impact, shear, and compression.

## Methods

There are several methods of comminution. Comminution of solid materials requires different types of crushers and mills depending on the feed properties such as hardness at various size ranges and application requirements such as throughput and maintenance. The most common machines for the comminution of coarse feed material are the jaw crusher (1m > P80 > 100 mm), cone crusher (P80 > 20 mm) and hammer crusher. Primary jaw crusher product in intermediate feed particle size ranges (100mm > P80 > 20mm) can be ground in Autogenous or Semi-Autogenous (AG or 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 IsaMillTM are used.

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.

## References

1. ^ Gupty, Chiranjib Kumar (2003). Chemical Metallurgy. Wiley-VCH Verlag. p. 130. Retrieved August 22, 2010.
2. ^ a b c Kanda, Yoshiteru; Kotake, Naoya (2007). "Chapter 12: Comminution Energy and Evaluation in Fine Grinding". In Salman, Agba D.; Hounslow, Michael J. Handbook of Powder Technology, Volume 12: Particle breakage. Elsevier. pp. 529–551. Retrieved August 20, 2010.
3. ^ Sibson, R.H. (1986). "Earthquakes and rock deformation in crustal fault zones". Annual Reviews of Earth and Planetary Science 14: 156. Retrieved 2 July 2011.
4. ^ Kick, F.M. Das Gesetz der proportionalen Widerstände und seine anwendung felix. Leipzig, Germany. 1885.
5. ^ Bond, Fred C. (1975) It Happened to Me, Ch. 130. Amazon.com. Retrieved May 29, 2011.
6. ^ Bond, F.C. The third theory of comminution.Trans. AIME, vol. 193, 1952. pp. 484–494.
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.

Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.

By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.