3. Differential liquid-liquid extractors (non-individualized stages)

In addition to high specific flow rates, the economic optimization of a liquid-liquid extraction unit requires mechanical agitation to create the maximum interfacial exchange area compatible with phase separation and circulation. What's more, in the case of differential contactors, it presupposes piston-type counter-current flow, the ideal regime that equipment manufacturers aim to approach.

Unlike staged contactors, where concentration gradients can be adjusted at each stage by adapting its individual efficiency, columns can exhibit significant deviations from ideality, caused by hydrodynamics, which considerably reduce performance.