Solvent extraction is a method to separate compounds based on their relative solubility in two different immiscible liquids. Compared with other separation methods, it gives a better separation effect than chemical precipitation, and a higher degree of selectivity and faster mass transfer than the ion exchange method. Solvent extraction is the process in which a compound transfers from one solvent to another owing to the difference in solubility or distribution coefficient between these two immiscible (or slightly soluble) solvents. In recent years, a series of new separation techniques have been developed combining solvent extraction technology with other technologies. Advantages of Solvent Extraction are low energy consumption, large production capacity, fast action, easy continuous operation and ease of automation.