Liquid-liquid extraction is an important process for separating components based on their relative solubilities in two immiscible liquid phases. In extraction units, a feed containing the solute enters the extractor and contacts a solvent. The solvent selectively absorbs the solute and forms an immiscible phase with the feed stream. The solute can then be separated from the solvent.
This article discusses the basics of liquid-liquid extraction and provides guidance on selecting the appropriate solvent and extraction equipment. It also touches on unit design and the importance of where temperature, pressure, and level control devices are located. The article introduces key concepts and equations associated with designing a liquid-liquid extraction process.