Liquid-Liquid Extraction: Principles and Applications

This lecture introduces the concept of liquid-liquid extraction as a separation process distinct from distillation. The instructor explains the fundamentals of this two-phase system, where a solute is transferred from one liquid to another. Key learning outcomes include comparing liquid-liquid extraction with distillation, calculating the number of stages required for extraction, and analyzing different flow configurations such as countercurrent and cross-current. The lecture emphasizes the importance of selecting an ideal solvent, which should possess high solubility for the solute, be immiscible with the diluent, and meet various stability and environmental criteria. The instructor discusses industrial applications of liquid-liquid extraction in sectors like petroleum, pharmaceuticals, and metals. The Gibbs phase rule is introduced to understand the degrees of freedom in the system, and the lecture covers mass transfer principles in continuous steady-state operations. The instructor also presents graphical methods for determining operating lines and equilibrium relationships, culminating in exercises to reinforce the concepts discussed.