1. Introduction

A correctly calculated liquid-liquid extraction unit, whether a discretized-stage or differential unit, must :

• ensure treatment of a fixed load flow ;

• supply products (extract and raffinate) meeting certain purity specifications while respecting a certain recovery rate.

The first of these obligations is linked to the device's limiting capacity (clogging), which depends on hydrodynamic phenomena, while the second depends on the difficulty of separation, i.e. phenomena linked to material transfer kinetics (residence time) and flow defects linked to axial mixing phenomena. In the case of differential devices, clogging will be characterized by its diameter, while material transfer profiles will be characterized by their height.

Early extraction column...