In investigating the performance of an extraction column in which axial concentration profiles were measured

a simplex method has been proposed for the simultaneous determination of axial dispersion and mass transfer coefficients from steady state data. The axial concentration at any point in continuous flow equipment is dependent on both the rate of material transfer and degree of dispersion. Consequently

parameters representing these effects should be obtainable by fitting the solution of a characteristic model equation to the experimentally determined cincentration profiles. In an extraction column of 5 cm inner diameter with a trapezoidal pulse

concentration profiles of Th in two phases (30% TBP (OK) and Th(NO3)4-HNO3-H2O) and two plate cartridges were measured. The diffusionmode] equation is used to describe the mass transfer process

and computed values obtained agree with experimental steady state profile data satisfactorily . Results show that axial dispersion coefficients of a trapfzoidal pulse column are smaller than those of a sine pulse

and that the column height for compensating axial dispersion is 32-44% of the apparent transfer unit height. When the simplex method is used for optimization

the approximation of the original differentia] equations with difference equations leads to linear systems of equations. The elimination method is used to solve directly each system (x or y) of equations

and the iterative method is used to solve a system (x and y) of equations. The program is very simple

the conver gence fast.Calculating a data set takes about 1 mm a minicomputer PDF 11/23.