AbstractA procedure for obtaining equilibrium data and predicting ideal‐stage requirements in a complex liquid‐liquid extraction system is presented. Preliminary equilibrium data are obtained from a simulated column run involving a series of batch contacts operated in such a manner as to approach steady state countercurrent conditions. The flow ratios and stage requirements for continuous operation are then estimated by trial‐and‐error by use of a modified McCabe‐Thiele method.The procedure lends itself particularly well to those systems with interdependent distribution of the two components. Data for the separation of hafnium from zirconium are presented to show the utility of t