Solvent extraction of rare earth metal by a continuous stirred vessel

The solvent extraction of neodymium,a rare earth metal,was studied with a continuous stirred vessel. one of the widely used extractants,2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (pc-88a),diluted with kerosene was selected as an extracting organic solvent. first,the extraction equilibrium of neodymium between aqueous and organic phases was measured in a batch-wise experimental run. the distribution ratio of the metal increased with ph and the relation between the distribution ratio and the conditions was investigated using ordinary slope analysis. in the second stage,the continuous operation of the extraction process was carried out in a laboratory scale standard type stirred vessel,with a 0.08m inner diameter,equipped with six flat blade turbine impeller and four baffles conducted under various operating conditions. the fractional yields of neodymium increased as ph,and flow rate ratio of solvent relative to feed increased. the state of liquid-liquid dispersion,which should affect the mass transfer,was also discussed in terms of the drop size and the holdup of the organic dispersed phase. © school of engineering,taylor’s university.