Liquid-Liquid Extraction: Principles and Applications

This lecture introduces the principles of liquid-liquid extraction, a vital separation process in chemical engineering. The instructor begins by comparing liquid-liquid extraction with distillation, emphasizing the differences in equilibrium and operating lines. Key concepts such as solvent selection, ideal solvent properties, and industrial applications are discussed, highlighting the importance of solubility, immiscibility, and stability. The lecture covers the Gibbs phase rule to determine degrees of freedom in the extraction process. The instructor explains the continuous steady-state operation of liquid-liquid extraction, detailing mass transfer and equilibrium relationships. Various extraction configurations, including countercurrent and crossflow methods, are analyzed. The Kremser equation is introduced as an analytical tool for calculating the number of stages required for effective extraction. The lecture concludes with practical exercises, reinforcing the theoretical concepts and providing students with a comprehensive understanding of liquid-liquid extraction processes in industrial applications.