ABSTRACT
Liquid-liquid extraction (LLE) is an important unit operation that allows one to separate “uids based on solubility differences of solutes in different solvents. In liquid extraction, separation of liquid solution occurred as a result of contact with another insoluble liquid. If the components of the original solution are distributed differently between the two liquids, separation will result (Figure 8.1). Extraction is driven by chemical differences and it can be used in situations when distillation is impractical, such as separation of compounds with similar boiling points in which distillation is not viable, or mixtures containing temperature-sensitive components. The solution to be extracted is called the feed, and the liquid used in contacting is the solvent. The enriched solvent product is the extract and the depleted feed is called the Raf™nate [1]. In the design of liquid-liquid extraction column, there are two primary calculations:
1. The number of stages needed to make a separation. 2. The amount of solvent needed to make a separation.
