Ternary Systems

As in leaching, equilibrium in a three-component system can be represented on either (1) equilateral-triangle, (2) right-triangle, or (3) Ponchon-Savarit diagrams. As in leaching, the right-triangle and Ponchon-Savarit diagrams are more convenient.

Methods of the construction of the equilibrium diagrams are illustrated by examples later. Compositions may be expressed in terms of the mass fractions or mole fractions.

Extract and Raffinate Solvents

The solvent which is used to recover the solute from another solution is termed the extract solvent. The raffinate solvent is the solvent from which the desired solute is to be separated.

Conjugate Phases

Two phases which exist in equilibrium such that their compositions are independent of the total two-phase mixture are called conjugate solutions.

Conjugate Systems

The equilibrium compositions of conjugate phases are plotted in Fig. 8-1. A line such as AA ? connecting two conjugate phases is called a tie line. At the point P, called the plait point, the tie line disappears. At this point, the two conjugate phases are mutually soluble. The solubility curve EPF is obtained experimentally. Instead of showing many tie lines, a conjugate line or curve is drawn. This can be used to draw any tie...