What is solvent extraction? Give an example of a separation of mixture by this method.

Dear Student,
Solvent extraction is a method used to separate compounds based on the difference in solubility of its parts in a particular liquid (solvent). This is based on the principle of extraction of a substance due to the difference of its solubility in two different immiscible liquids.It is also called as liquid-liquid partitioning or liquid partitioning.

• Two solvents are used first in which the compound is to be dissolved before separation(feed solution)
• second solvent in which the substance goes after extraction(extracted solution)
• The raffinate is the unwanted or waste solvent that remains after extraction.
• The solubility of substance should be more in the extracted liquid.
• Usually aqueous - organic systems are used for solvent extraction and a distribution ratio is calculated -the distribution ratio is a measure of the effectiveness of the extraction process

Solvent extraction is mostly used petrochemical refining ,in separation of heavy oil and tar sand,also used in processing of vegetable oils and perfumes.
One of the simplest example is separation of iodine in water using pain thinner (acetone) as a solvent .
Regards!