The modelling of equilibrium data for the liquid-liquid extraction of metals Part I. A survey of existing models

The various approaches which have been made to model equilibrium data for the extraction of metals in liquid-liquid systems have been reviewed. The limitations of any one model are highlighted. Those models based on the known chemistry of the process can be used with confidence to extrapolate data outside an experimentally measured region of the equilibria but models with as good an, if not better, accuracy can be based on a generalised polynomial and this method does not require a detailed chemical study to be made.