Interfacial Phenomena in Solvent Extraction and Its Influence on Process Performance

Solvent extraction is now finding applications in a broader range of fields than the past. Many of these applications require process equipment with shorter contact times, and in some cases to the point where the traditional equilibrium stage approach is not a good model for predicting performance. In addition, feed streams are becoming lower in concentration of the solute. This means greater feed to solvent flow ratios are being used and so loss of organics as entrainment in the feed is more of a concern both economically and environmentally. These trends mean that a greater emphasis is being placed on the kinetics of extraction and stripping in models to predict performance and on formation and coalescence of drops to control entrainment. This paper reviews recent advances in the tools for investigating kinetics and coalescence in solvent extraction processes and some of the insights that are being uncovered in these fundamental processes in solvent extraction technology.