抄録
With the aim of finding an optimum temperature in fuel reprocessing with alkylamine, the effect of temperature on the extraction of nitric acid, uranium, zirconium and ruthenium with tri-n-octyl amine was investigated in the temperature range between 20° and 60°.
In the neutralization reaction for the extraction of nitric acid,
R3N+H++NO3- ?? R3NHNO3, (1)
the apparent equilibrium constants were determined for various temperatures. The average enthalpy change, average free energy change and average entropy change were found to be -16.3, -7.2 kcal/mol•deg and -8.0 e.u., respectively.
For the association reaction of nitric acid,
R3NHNO3+αHNO3 ?? R3NHNO3•αHNO3(2)
the average apparent enthalpy change was found to be 3.4 kcal/mol•deg, which corresponds to hydrogen bond energy.
The enthalpy change values were further determined for the extraction of uranium, zirconium and ruthenium, and found to be -1.3, 6.1 and 9.3 kcal/mol•deg. respectively.
Within the temperature range studied, the lower regions of temperature appear to provide better separation of fission products from uranium and from plutonium.
