The slip and characteristic velocities of the reactive system (samarium, gadolinium and D2EHPA) were investigated in the pilot plant Oldshue-Rushton extraction column. The experiments were carried out at the extraction and stripping stage. The influences of the agitation speed, dispersed as well as continuous phase velocity were studied. An increase in dispersed phase velocity led to the increase of the slip velocity while it decreased with agitation speed and continuous phase velocity. More buoyancy and faster upward movement of larger drops accelerate the slip velocity in the stripping condition as compared with the case of extraction condition. The experimental data were compared with the proposed correlations by Asadollahzadeh et al., and the related deviation was within 26% from these equations. Therefore, the modified correlations for prediction of slip and characteristic velocities were proposed with the experimental data and the data from the physical systems in the literature. (C) 2016 Elsevier B.V. All rights reserved.