ABSTRACT
In this chapter, the extraction by a solvent B (called sometimes the diluent B) of one solute S from its initial homogeneous solution in solvent A is studied. In particular, general considerations concerning the extraction of liquid-liquid are given; the concept of partition coefficient is recalled by starting from the solubilities of the solute to partition in the two solvents. The extraction of liquid-liquid is considered from the viewpoint of the phase rule; the treatment of ternary systems is investigated. An interesting result is obtained during the study of batch extraction from the viewpoint of the phase rule. In this case, the variance is 3. This is the number of factors that can play a part in the equilibrium. They can be, for example, the concentration of the solute, the pressure and temperature.
