What is Solvent extraction?
[[File:Separation02.ogv|frame|right|[[Benzoic acid]] is extracted from an organic compound. The solvent used is [[Methyl tert-butyl ether|MTBE]]. All of this is done in a diluted solution of [[Sodium bicarbonate]]. Benzoic acid is converted to [[Sodium benzoate]]. Sodium benzoate changes from the organic solvent to the water phase, neutral [[Benzil]] (shown in yellow) remains in the organic phase. In this case, the organic substance is on top, because the [[density]] of the organic solvent MTBE (0,74 g·cm<sup>−3</sup>) is lower than that of the other phase (about 1,00 g·cm<sup>−3</sup>).]] '''Solvent extraction''', also known as '''Liquid–liquid extraction''' or '''partitioning''', is a method to separate a compound based on the [[solubility]] of its parts. This is done using two [[liquid]]s that don't mix, for example [[water]] and an [[organic chemistry|organic]] [[solvent]]. Solvent extraction is used in the processing of [[perfume]]s, [[vegetable oil]], or [[biodiesel]]. It is also used to recover [[plutonium]] from [[radiation|irradiated]] [[nuclear fuel]], a process which is usually called [[nuclear reprocessing]]. The recovered plutonium can then be re-used as nuclear fuel. In this process one of the components of a mixture dissolves in a particular liquid and the other component is separated as a residue by filtration. <ref>{{Cite web|url=http://www.seaofindia.com/About%20Us|title=Solvent Extractors' Association of India|first=|last=|website=SEA India|publisher=|accessdate=|archive-date=2017-04-29|archive-url=https://web.archive.org/web/20170429115452/http://www.seaofindia.com/About%20Us|url-status=dead}}</ref> Solvent extraction involves crushing of oil seeds and oil seed cakes. From ancient time, vegetable oils were obtained by crushing oil seeds in village ghanis / kolhus / chekkus in India. At the beginning of the 20th century the vegetable oils industry was based on some 500,00 bullock-driven ghanis producing about 800,000 tonnes of oils. Slowly, in addition to these ghanis, power-driven ghanis (r