solvent extraction


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solvent extraction

[′säl·vənt ik‚strak·shən]
(chemical engineering)
The separation of materials of different chemical types and solubilities by selective solvent action; that is, some materials are more soluble in one solvent than in another, hence there is a preferential extractive action; used to refine petroleum products, chemicals, vegetable oils, and vitamins.
(nucleonics)
A process for removing uranium fuel residue from used fuel elements of a reactor; it generally involves decay cooling under water for up to 6 months, removal of cladding, dissolution, separation of reusable fuel, decontamination, and disposal of radioactive wastes. Also known as liquid extraction.

Solvent extraction

A technique, also called liquid extraction, for separating the components of a liquid solution. This technique depends upon the selective dissolving of one or more constituents of the solution into a suitable immiscible liquid solvent. It is particularly useful industrially for separation of the constituents of a mixture according to chemical type, especially when methods that depend upon different physical properties, such as the separation by distillation of substances of different vapor pressures, either fail entirely or become too expensive.

Industrial plants using solvent extraction require equipment for carrying out the extraction itself (extractor) and for essentially complete recovery of the solvent for reuse, usually by distillation.

The petroleum refining industry is the largest user of extraction. In refining virtually all automobile lubricating oil, the undesirable constituents such as aromatic hydrocarbons are extracted from the more desirable paraffinic and naphthenic hydrocarbons. By suitable catalytic treatment of lower boiling distillates, naphthas rich in aromatic hydrocarbons such as benzene, toluene, and the xylenes may be produced. The latter are separated from paraffinic hydrocarbons with suitable solvents to produce high-purity aromatic hydrocarbons and high-octane gasoline. Other industrial applications include so-called sweetening of gasoline by extraction of sulfur-containing compounds; separation of vegetable oils into relatively saturated and unsaturated glyceride esters; recovery of valuable chemicals in by-product coke oven plants; pharmaceutical refining processes; and purifying of uranium.

Solvent extraction is carried out regularly in the laboratory by the chemist as a commonplace purification procedure in organic synthesis, and in analytical separations in which the extraordinary ability of certain solvents preferentially to remove one or more constituents from a solution quantitatively is exploited. Batch extractions of this sort, on a small scale, are usually done in separatory funnels, where the mechanical agitation is supplied by handshaking of the funnel.

References in periodicals archive ?
For solvent extraction, methyl ethyl ketone (MEK), petroleum ether (PE), dichloromethane (DCM) and ethanol were used in this work.
Combining mechanical solvent removal with conventional solvent extraction significantly increases the extraction rate while simultaneously reducing the amount of extraction solvent required to produce ultrahigh strength UHMWPE fiber.
The first form, a 97% (see note*) purity cerium oxide, was produced via classic solvent extraction techniques.
The synergistic solvent extraction of the lanthanoids was studied using a traditional and effective means of obtaining both stoichiometric and equilibrium constant information about extraction processes, called "slope analysis".
For homogenate analysis without solvent extraction, we diluted homogenates 2-fold in PGT to obtain a final concentration of 0.
Apparently, the falsely increased serum estradiol by direct assay was caused by some water-soluble interferant that could be removed by a simple organic solvent extraction.
and the Canadian Government have signed a technology-transfer agreement that will advance the use of microwave energy for solvent extraction for molecular analysis.
Solvent extraction, a workhorse of process chemistry, diffuses one chemical through some material--a sample of contaminated soil, for example, or an herb from which essential oils will be harvested.
He also described solvent extraction techniques that attempt to quantify melt cleanliness levels.
The main challenge in modern solvent extraction separation is that most techniques are mainly empirical, specific and particular for narrow fields of practice and require a large degree of experimentation.
They developed a direct solvent extraction technique that is simple, and that can be as efficient and reproducible as the EU Soxhlet method.