Influence of hydrofluoric acid on extraction of thorium using a commercially available extraction chromatographic resin

Fujiwara, Asako ; Hoshi, Akiko ; Kameo, Yutaka ; Nakashima, Mikio

Dependence of Th recovery on HF concentration in nitric acid solutions (15 mol/dm) containing 110 mol/dm of Th and various concentrations of HF was studied using a commercially available UTEVA resin column (for uranium and tetravalent actinide). Thorium recovery decreased with an increase in the HF concentration in the sample solutions. The concentration of HF at which Th recovery started to decrease was about 110 mol/dm in 1 mol/dm HNO solution, about 110 mol/dm in 3 mol/dm HNO solution, and about 110 mol/dm in 5 mol/dm HNO solution. When Al(NO) (0.2 mol/dm) or Fe(NO) (0.6 mol/dm) was added as a masking agent for F into the Th solution containing 110 mol/dm HF and 1 mol/dm HNO, the Th recovery improved from 1.40.3% to 955% or 933%. Effective extraction of Th on UTEVA resin was achieved by selecting the concentration of HNO and/or adding masking agents such as Al(NO) according to the concentration of HF in the sample solution.