Governing Equations and Relationships

Consider a single stage extraction process, Eig. 2A, where a feed liquid (i.e., water) containing a solute (i.e., acetone) contacts an extraction solvent (i.e., chloroform). In this 

Now consider a multiple-stage process with countercurrent flow of the raffinate and extract phases. Fig. 2B. Countercurrent is the most efficient multistage configuration. One can write a mass balance around the nth stage, as indicated by envelope 1, using the following units for a continuous flowing process  

If we assume that each stage results in the exit streams being in equilibrium, we can also write a second equation relating F to X, from the previous discussion on equilihrium  

Note in Fig. 3 the curve for A = 1, which is the critical value of the dimensionless group, the extraction factor. Based on the critical value of 1 for the extraction factor, A, the following can he observed in Fig. 3  

Type 2 liquid/liquid extraction involves two bulk liquids that are partially immiscible. Therefore, both phases contain significant fractions of both liquids in addition to the 

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