Liquid-Liquid Extraction in a Rotating-Spray Column: Removal of Cr(VI) by Aliquat 336

The effect of centrifugal force on mass-transfer rates in liquid-liquid extraction was investigated experimentally in a rotating-spray column. Extraction with interfacial chemical reaction was studied in this contactor by countercurrent contact Of a dilute aqueous solution of hexavalent chromium (pH 2) with an extractant-Aliquat 336 (quaternary ammonium salt)-dissolved in kerosene (dispersed phase). The overall volumetric mass-transfer coefficient, based oil a continuous phase (assuming plug flow of the phases), was measured to be all order higher than that in a conventional spray column. A mathematical model was developed for this contactor, considering axial dispersion in the continuous phase and internal circulation within drops. Simulation results suggested that the variation of k(c)a, relative to the flow rate of the aqueous phase, was not significant at a constant rotor speed and a constant flow rate of the organic phase.