Concentration of uranium from carbonate type eluate by ultrafiltration method

An ultrafiltration method was applied to the concentration of uranium and the recovery of the eluting agent from the carbonate type eluate that had been obtained in the extraction process of uranium from sea water with titanium-activated carbon composite adsorbent. In the case of the eluate obtained from 0.5N NaHCO3 solution, the water flux was 4 x 10-3 cm/min at 4 kg/cm2 with the membrane of fractional molecular weight 500, and the retentions were 98%, 14%, and 85% for uranium, NaHCO3, and total organic carbon, respectively. When the eluate was concentrated as much as 14 times, uranium was concentrated 10 times, and 85% of NaHCO3 was permeated into the filtrate. The permeative properties of the membrane were scarcely influenced by the repetition of the concentration for 4 times. The retention of uranium was about 25% lowered although the water flux was raised when the membrane of higher fractional molecular weight (1,000) was used. The retention of uranium was the same in the case of the eluate obtained from 1N (NH4) 2CO3 solution as that from the NaHCO3 solution, but the recovery of (NH4)2CO3 was low probably due to the vaporization of NH3 and CO2 during the filtration