Effect of Temperature on the Extraction of Nitric Acid, Uranium and Fission Products with Tri-n-Octyl Amine

Abstract

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-octylamine was investigated in the temperature range between 20° and 60°C. In the neutralization reaction for the extraction of nitric acid 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 8.0e.u., respectively. For the association reaction of nitric acid the average apparent enthalpy change was found to be 3.4kcal/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 uran...