Abstract: A liquid extraction process using counterflowing liquid phases in a reciprocating plate extraction column in which the plates of the column are spaced with respect to one another approximately according to the equation: ##EQU1## wherein l is the plate spacing, U.sub.D is the superficial velocity of the dispersed phase at flooding, U.sub.C is the superficial velocity of the continuous phase at flooding, .DELTA..rho. is the density difference and .sigma. is the interfacial tension.By using the above equation the volume of column required to carry out a specific extraction is minimized.The extraction column comprises a casing, a reciprocating shaft in the casing having perforated plates and, optionally, baffle plates mounted thereon in a spatial relationship with respect to each other calculated on the basis of the equation and includes motive means and suitable cam and driving means to reciprocate the shaft.