Refining
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220668102
2008-06-20T23:58:08Z
Neelix
1169106
Added other title
'''Refining''' (also called '''affining''') is the process of [[purification]] of a [[chemical compound|substance]]. The term is usually used of a [[natural resource]] that is almost in a usable form, but which is more useful in its pure form. For instance, most types of natural [[petroleum]] will burn straight from the ground, but it will burn poorly and quickly clog an engine with residues and byproducts. The term is broad, and may include more drastic transformations, such as the reduction of [[ore]] to [[metal]] (for which see [[Refining (metallurgy)]]).
The refining of [[liquid]]s is often accomplished by [[distillation]] or [[fractional distillation|fractionation]]. [[Gas]]es can be refined in this way as well, by being cooled and/or compressed until they liquefy. Gases and liquids can also be refined by [[solvent extraction|extraction]] with a selective [[solvent]] that dissolves away either the substance of interest, or the unwanted impurities.
Many [[solid]]s can be refined by growing [[crystal]]s in a [[solution]] of the impure material; the regular structure of the crystal tends to favor the desired material and exclude other kinds of particles.
[[Chemical reaction]]s are often used to remove impurities of particular types.
The use of [[silicon]] and other [[semiconductor]]s in [[electronics]] is highly dependent on precise control of impurities, and a number of special techniques have been developed, such as [[zone refining]].
Types of materials that are usually refined:
* [[metal]]s - see [[Refining (metallurgy)]]
* [[petroleum]]
* [[silicon]]
* [[sugar]]
* [[vegetable oil]]
==See also==
*[[Refinery]]
*[[Continuous distillation]]
*[[Oil refinery]]
*[[Natural gas processing]]
[[Category:Industrial processes]]
[[da:Raffinering]]
[[de:Raffination]]
[[es:Refinación]]
[[fa:پالایش]]
[[fr:Raffinage]]
[[is:Hreinsun]]
[[it:Raffinazione]]
[[ka:აფინაჟი]]
[[ja:精錬]]
[[nl:Raffinage]]
[[no:Foredling]]
[[pl:Rafinacja]]
[[ru:Аффинаж]]
[[sh:Rafiniranje]]
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[[zh:精炼]]