{{Short description|Method that converts a mixture or solution into two or more distinct products}}
{{Chemical engineering }}
-A '''separation process''' is a method that converts a mixture or solution of chemical substances into two or more distinct product mixtures.<ref>{{cite book|editor-first=Ian D. |editor-last=Wilson|editor2-first= Edward R. |editor2-last=Adlard |editor3-first=Michael |editor3-last=Cooke |editor4-first=Colin F. |display-editors = 3 |editor4-last=Poole |title=Encyclopedia of separation science|year=2000|publisher=Academic Press|location=San Diego|isbn=978-0-12-226770-3}}</ref> At least one of results of the separation is enriched in one or more of the source mixture's constituents. In some cases, a separation may fully divide the mixture into pure constituents. Separations exploit differences in chemical properties or physical properties (such as size, shape, mass, density, or chemical affinity) between the constituents of a mixture.
+A '''separation process''' is a method that converts a mixture or solution of chemical substances into two or more distinct product mixtures.<ref>{{cite book|editor-first=Ian D. |editor-last=Wilson|editor2-first= Edward R. |editor2-last=Adlard |editor3-first=Michael |editor3-last=Cooke |editor4-first=Colin F. |display-editors = 3 |editor4-last=Poole |title=Encyclopedia of separation science|year=2000|publisher=Academic Press|location=San Diego|isbn=978-0-12-226770-3}}</ref> At least one product mixture of the separation is enriched in one or more of the source mixture's constituents. In some cases, a separation may fully divide the mixture into pure constituents. Separations exploit differences in chemical properties or physical properties (such as size, shape, mass, density, or chemical affinity) between the constituents of a mixture.
Processes are often classified according to the particular differences they use to achieve separation. If no single difference can be used to accomplish the desired separation, multiple [[unit operation|operations]] can often be combined to achieve the desired end.
With a few exceptions, [[chemical element|element]]s or [[Chemical compound|compound]]s exist in nature in an impure state. Often these raw materials must go through a separation before they can be put to productive use, making separation techniques essential for the modern industrial economy.
-The purpose of separation may be ''analytical'', can be used as a lie component in the original mixture without any attempt to save the fractions, or maybe ''preparative'', i.e. to "prepare" fractions or samples of the components that can be saved. The separation can be done on a small scale, effectively a [[laboratory]] scale for analytical or preparative purposes, or on a large scale, effectively an industrial scale for preparative purposes, or on some intermediate scale.
+The purpose of separation may be ''analytical'', i.e. to identify the size of each fraction of a mixture is attributable to each component without attempting to harvest the fractions. The purpose of a separation may maybe ''preparative'', i.e. to "prepare" fractions for input into processes that benefit when components are separated.
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+Separations may be performed on a small scale, such as in a [[laboratory]] for analytical purposes. Separations may also be performed on a large scale, such as in a [[chemical plant]].
==Complete and incomplete separation==
-Types of separation, separations require total purification, as in the [[Hall–Héroult process|electrolysis refining]] of [[bauxite]] ore for [[aluminum]] metal, but a good example of an incomplete separation technique is [[petroleum|oil]] refining. Crude oil occurs naturally as a mixture of various [[hydrocarbon]]s and impurities. The refining process splits this mixture into other, more valuable mixtures such as [[natural gas]], [[gasoline]] and [[Oil#Chemical feedstock|chemical feedstocks]], none of which are pure substances, but each of which must be separated from the raw crude. In both of these cases, a series of separations is necessary to obtain the desired end products. In the case of oil refining, crude is subjected to a long series of individual [[distillation]] steps, each of which produces a different product or intermediate
+Some types of separation require complete purification of a certain component. An example is the production of [[aluminum]] metal from [[bauxite]] ore through [[Hall–Héroult process|electrolysis refining]]. In contrast, an incomplete separation process may specify an output to consist of a mixture instead of a single pure component. A good example of an incomplete separation technique is [[petroleum|oil]] refining. Crude oil occurs naturally as a mixture of various [[hydrocarbon]]s and impurities. The refining process splits this mixture into other, more valuable mixtures such as [[natural gas]], [[gasoline]] and [[Oil#Chemical feedstock|chemical feedstocks]], none of which are pure substances, but each of which must be separated from the raw crude.
-==Separating liquids==
-Separators are used to divide liquids. Vertically supported centrifuges are built with flying bearings. A separator is a continuous sedimentation [[centrifuge]]. Both exit streams are continuously discharged, using a pump (under pressure) or pressure-free. The solid material can be discharged discontinuously (chamber drum, solid-walled disc drum), pseudo continuously (self-cleaning disc drum) or continuously (nozzle drum). The drum is the centerpiece of the separator, in which the separation process takes place. There are two types of drums: the chamber drum (known as chamber separators) and the disc drum (known as [[Conical plate centrifuge|disc separators]]). The power transmission on the spindle and thereby on the drum can take place by using one of the three drive motors: helical gears, a belt drive or direct drive, via a special motor. The sealing of the separators is differentiated into four types: open, semi-closed, hydro-hermetic (sealing of the product space) or fully [[Airtight|hermetic]] (absolute airtight).
+In both cases of complete and incomplete separation, a series of separations may be necessary to obtain the desired end products. In the case of oil refining, crude is subjected to a long series of individual [[distillation]] steps, each of which produces a different product or [[Reaction intermediate#Chemical_processing_industry|intermediate]].
==List of separation techniques==
*[[Sponge]], adhesion of atoms, ions or molecules of gas, liquid, or dissolved solids to a surface
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