The flow behaviours of three extraction systems were studied. Experiments on 30%TBP (OK)-water system showed the obvious effect of wettability of dispersed phase on perforated plate upon holdup. When amplitude was lower than 0.6cm

axial dispersion was not serious

and the reciprocating plate extraction column was found to possess good performance for the 30% TBP(OK)-water system. The flooding characteristics of isopropyl acetate-water (10% acetic acid

7% sodium sulfate)system and heavy benzene-ammonia water(0.2% phenol) system were investigated. The sizes of two plant-scale columns for the recovery of acetic acid and phenol were estimated.