Editing Refining

{{Short description|Process of purification}}
{{More citations needed|date=February 2024}}
'''Refining''' is the process of [[List of purification methods in chemistry|purification]] of a (1) [[chemical compound|substance]] or a (2) [[Theory of Forms|form]]. 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.<ref>{{Cite book |last=Parkash |first=Surinder |url=https://books.google.com/books?id=FWWL64UreQ4C&q=%22Refining%22+-wikipedia |title=Refining Processes Handbook |date=2003-10-16 |publisher=Elsevier |isbn=978-0-08-052385-9 |pages=xii |language=en}}</ref> 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 by-products. 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]]; this process is useful, for example, for isolating different fractions of [[petroleum]].  [[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 (chemistry)|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]] depends on precise control of impurities. The [[zone melting]] process developed by [[William Gardner Pfann]] was used to produce pure [[germanium]], and subsequently [[float-zone silicon]] became available when Henry Theuerer of [[Bell Labs]] adapted Pfann's method to silicon.

Types of materials that are usually refined:
* [[metal]]s (see [[Refining (metallurgy)]]
* [[petroleum]] (see [[Oil refinery]])
* [[silicon]]
* [[sugar]] (see [[Sugar refinery]])
* [[flour]] (see [[Gristmill]])
* [[table salt]]
* [[vegetable oil]] (see [[Cooking oil#Refinement|Food oil refinement]] for food use and [[Vegetable oil refining (disambiguation)|Vegetable oil refining]] for biofuel use)
* [[air]]
* [[refining (glass)|glass]]

==See also==
*[[Continuous distillation]]
*[[Natural gas processing]]
*[[Refinery]]
*[[Wafer (electronics)]]
*[[Air separation]]

==References==
{{reflist}}

{{Authority control}}

[[Category:Industrial processes]]