The effect of temperature on the extraction of uranium(VI) from nitric acid by tri-n-butyl-phosphate

The Effect of the Structure of Trialkyl Phosphates on their Physicochemical Properties and Extraction Behavior

“…9 are also shown in Table 9, which also presents D U(VI) values reported in the literature on the studies carried out under identical conditions. D U(VI) values for the extraction by TAP reported by Srinivasan et al [29] and the D U(VI) values for the extraction by TBP reported by Bagawde et al [30] are shown in Table 9. D values for the extraction of U(VI) by 1.09 M trialkyl phosphate in n-dodecane from 3 M HNO 3 at 303 K reported by Siddall [14] are also presented in Table 9.…”

Effect of temperature on the extraction of uranium by TiAP/n-dodecane

“…4 and 5, respectively, as a function of equilibrium aqueous phase nitric acid concentration for 1.1 M and 0.55 M TiAP/ndodecane. Also included in the figures for comparison are the corresponding enthalpies of extraction of uranyl nitrate by identical concentrations of TBP [15] and TAP [16] reported in literature under identical equilibrium aqueous phase acidities. A comparison of the enthalpies of extraction by 1.1 M and 0.55 M TiAP is depicted in Fig.…”

“…These experiments were done in temperature range of 293-333K with 10K interval and nitric acid concentration varying from 0.1 M to 9 M. Enthalpies of extraction at all the different concentration were calculated by the "second law method" using van't Hoff equation. The results were compared with those done with TBP [15] and TAP [16] under identical conditions.…”

Extraction of U(vi) From Nitrate and Thiocyanate Media With Monoamides

“…The log K ex values evaluated at all the temperatures for the NO 3 À and SCN À systems are given in Table 4 and a plot of log K ex vs. 1=T (in degree Kelvin) is given in Fig. Table 5 gives the thermodynamic parameters for the formation of UO 2 2þ complexes with DHDA from NO 3 À and SCN À media at 25 C along with the literature data for UO 2 2þ -HNO 3 -DHDA, [18] TBP [27] and tri-n-amyl phosphate (TAP). From the slope of the straight lines, DH has been evaluated using the van't Hoff equation.…”

“…Table 5 gives the thermodynamic parameters for the formation of UO 2 2þ complexes with DHDA from NO 3 À and SCN À media at 25 C along with the literature data for UO 2 2þ -HNO 3 -DHDA, [18] TBP [27] and tri-n-amyl phosphate (TAP). [27], for the UO 2 2þ -HNO 3 -TBP=dodecane system it is reported that while keeping HNO 3 constant at 1.0 M, the DH value is À25.7 and À18.1 kJ=mol when the TBP concentration was respectively 2.5% ($0.1 M) and 15% ($0.56 M). The DH value for the formation of UO 2 (NO 3 ) 2 Á 2DHDA species was calculated to be À24.8 kJ=mol, when the aqueous phase was 5.0 M NaNO 3 and DHDA 0.25 M in dodecane.…”