I. Introduction of liquid liquid extraction(LLE)

Liquid Liquid Extraction is also called LLE, also known as solvent extraction. It is a method of transferring solutes/substances(A) from Aqueous feed to another immiscible solvent(S) by utilizing the differences in solubility or partition coefficients of substances in two immiscible (or slightly soluble) liquids.

Technical Terms related to liquid-liquid extraction

II. Application of Liquid liquid extraction:

Liquid-liquid extraction is widely used in various industries such as pharmaceuticals, chemical engineering,hydrometallurgy, environmental analysis, and food processing for purposes like purification, separation, and concentration of substances.

III. Liquid liquid extraction methods

The two main process of liquid liquid extraction is : Multi-stages Continuous Countercurrent Extraction & Multi-stages Continuous Cross Current Extraction.

IV. Equipment used in liquid liquid extraction process:

Mixer-Settlers: Mixer-settler units consist of mixing chambers where the two liquid phases are brought into contact and settling chambers where they separate based on density differences. This type of equipment is commonly used for solvent extraction in hydrometallurgical processes.

Centrifugal Extractors: Also known as centrifugal contactors, these devices use centrifugal force to enhance the mixing and separation of liquids. They are effective for high-throughput liquid-liquid extraction processes.

Others: like exraction column, Membrane Extraction system etc.

V. Liquid liquid extraction steps:

  1. Solvent selection: When design an liquid liquid extraction plant, the first step is to select the extractant(solvent) which is immiscible with the aqueous liquid , and has a high affinity for the target substance to be extracted.
  2. Mixing: mixing the solvent and aqueous phase togethers and agitating, to make two phases contact sufficiently.
  3. Phases separation: the aqueous phase and organic phase will be separated by natural gravity or centrifugal force(depends on the equipment you used) according to their different densities.
  4. Washing: You may need a washing step to remove the impurities, then make sure the purity of extracted compounds.
  5. Stripping: also called back-extraction, it is the reverse process of extraction. The process of using a reverse extractant to return the extracted substance from the loaded organic phase back to the aqueous phase.
  6. Drying/evaporation: If needed, remove any water or residual solvent from the extracted compound by evaporating.

Welcome to consult TIEI EXTRACTION for more information about liquid liquid extraction(LLE)!