Comminution

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Comminution is the reduction of solid materials from one average particle size to a smaller average particle size, by crushing, grinding, cutting, vibrating, or 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 unit operation in mineral processing, ceramics, electronics, and other fields, accomplished with many types of mill. In dentistry, it is the result of mastication of food. In general medicine, it is one of the most traumatic forms of bone fracture.

Contents

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:

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 (primary crushers) are the jaw crusher (1m > P80 > 100 mm), cone crusher (P80 > 20 mm) and 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. Trituration can further be described as levigation (trituration of a powder with a non-solvent 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

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Feed manufacturing refers to the process of producing animal feed from raw agricultural products. Fodder produced by manufacturing is formulated to meet specific animal nutrition requirements for different species of animals at different life stages. According to the American Feed Industry Association (AFIA), there are four basic steps:

  1. Receive raw ingredients: Feed mills receive raw ingredients from suppliers. Upon arrival, the ingredients are weighed, tested and analyzed for various nutrients and to ensure their quality and safety.
  2. Create a formula: Nutritionists work side by side with scientists to formulate nutritionally sound and balanced diets for livestock, poultry, aquaculture and pets. This is a complex process, as every species has different nutritional requirements.
  3. Mix ingredients: Once the formula is determined, the mill mixes the ingredients to create a finished product.
  4. Package and label: Manufacturers determine the best way to ship the product. If it is prepared for retail, it will be "bagged and tagged," or placed into a bag with a label that includes the product's purpose, ingredients and instructions. If the product is prepared for commercial use, it will be shipped in bulk.

Dry milling of grain is mainly utilized to manufacture feedstock into consumer and industrial based products. This process is widely associated with the development of new bio-based associated by-products. The milling process separates the grain into four distinct physical components: the germ, flour, fine grits, and coarse grits. The separated materials are then reduced into food products utilized for human and animal consumption.

References

  1. ↑ Gupty, Chiranjib Kumar (2003). Chemical Metallurgy. Wiley-VCH Verlag. p. 130. ISBN   9783527605255 . Retrieved August 22, 2010.
  2. 1 2 3 Kanda, Yoshiteru; Kotake, Naoya (2007). "Chapter 12: Comminution Energy and Evaluation in Fine Grinding". In Salman, Agba D.; Hounslow, Michael J. (eds.). Handbook of Powder Technology, Volume 12: Particle breakage. Elsevier. pp. 529–551. ISBN   9780080553467 . Retrieved August 20, 2010.
  3. ↑ Sibson, R.H. (1986). "Earthquakes and rock deformation in crustal fault zones" (PDF). Annual Review of Earth and Planetary Sciences. 14: 156. Bibcode:1986AREPS..14..149S. 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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