Liquid-liquid extraction (LLX), or solvent extraction or partitioning, is a selective separation procedure for isolating and concentrating a valuable substance from an aqueous solution by using an organic solvent. LLX can serve as an alternative when distillation is ineffective. LLX is used in pharmaceutical, food and agricultural processing, organic and inorganic chemistry, hydrometallurgy and fragrances.
In mixer-settler type extraction, feed and solvent tanks are monitored for level. The feed and solvent are thoroughly blended in a mixer-settler chamber and the mixture overflows into a separation chamber where it settles into light and heavy phases. The separate phases are monitored and removed on interfacial level control.