7. Conclusion

Over the past forty years, liquid-liquid extraction has become as mature an industrial operation as distillation. However, its implementation is still subject to the resolution of delicate problems often linked to the thermodynamics of systems, particularly hydrometallurgical systems, for which there is no equivalent to thermodynamic databases.

Many efforts are being made to establish rigorous selection criteria for predicting the performance of different types of extractor. Comparative methods using reference systems are recommended. The practical application of these results is often linked to a better understanding of interface phenomena.

The use of new materials (polymers, ceramics, etc.) extends the application range of commercial contactors to new corrosion conditions (hydrohalic acid, high temperatures and pressures).