抄録
The extraction equilibrium of Th (NO3)4 and HNO3 in TBP–CCl4 solution was studied. The vapor pressures of H2O and HNO3 over the aqueous solution containing HNO3 and Th(NO3)4 were measured, and the activity of each component in the ternary aqueous solution was calculated.
Conventional distribution measurements of Th(NO3)4 and HNO3 between organic and aqueous phases were conducted in addition to the measurement of infrared absorption spectra of the organic phase. The water concentration in the organic phase was also measured. Based on the experimental results, the composition and aggregation number of the extracted species containing Th(NO3)4 and HNO3 and the apparent equilibrium constants of extraction were determined, respectively: it was assumed that the extracted species in the organic phase are TBP, TBP · H2O, Th (NO3)4 · mTBP and nTBP · HNO3. The results were as follows:
Th(NO3)4·2TBP, K′T=35.0
(TBP·HNO3)2, K′N=0.32
