DILUENT AND EXTRACTANT EFFECTS ON THE ENTHALPY OF EXTRACTION OF URANIUM(VI) AND AMERICIUM(III) NITRATES BY TRIALKYL PHOSPHATES

The effect of various diluents such as n-hexane, n-heptane n-octane, i sooctane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-hexadecan e, cyclohexane, benzene, toluene, p-xylene, mesitylene and o-dichlorob enzene on the enthalpy of extraction of uranyl nitrate by tri-n-amyl p hosphate (TAP) over the temperature range 283 K - 333 K has been studi ed. The results indicate that the enthalpy of extraction does not vary significantly with the diluents studied. Also enthalpies of extractio n of uranyl nitrate and americium(III) nitrate by neutral organo phosp horous extractants such as tri-n-butyl phosphate (TBP), tri-n-amyl pho sphate (TAP), tri-sec-butyl phosphate (TsBP), tri-isoamyl phosphate (T iAP) and tri-n-hexyl phosphate (THP) have been studied. An attempt has been made to explain the trends, on the basis of the nature of the so lvate formed and the different terms which contribute to the overall e nthalpy change.