Separation of Th^(4+) and RE^(3+) with Hollow Fiber Extraction

Separation of Th4+ and RE3+ was investigated by hollow fiber membrane extraction with N1923 in countercurrent recirculating operation. The effect of H+ concentration in aqueous phase and flow rates of aqueous and organic phases on mass transfer coefficient was tested. Then the extraction of Th4+ from RE sulfate obtained from Baotou ore was carried out. The results obtained show that the mass transfer coefficient of Th4+ changes with the flow rate of aqueous phase, but does not change with the flow rate of organic phase and H+ concentration in aqueous phase, which suggests that the mass transfer rate of Th4+ is controlled by that in the water critical layer. The mass transfer rate of RE3+ does not change with the flow rate of water phase, changes a little with the flow rate of organic phase, and changes with H+ concentration, which suggests that the mass transfer rate is controlled by their reaction rate with N1923. Th4+ could be extracted completely in 8 h from RE sulfate solution of Baotou ore withrelatively less extraction of RE3+. So the separation of radioactive element under the sealed condition could be done.