Nitric Acid Extraction into a TODGA Solvent Modified with 1-Octanol

Abstract

Distribution data for the partition of nitric acid between nitric acid solution and a solvent phase comprising various combinations of TODGA, octanol and inert kerosene diluent have been generated, covering a range of conditions from 0-9 mol/L HNO3(aq), 0-100% octanol, 0-0.4 mol/L TODGA over a temperature range from 10-50 °C. The data have been used to derive a model describing the nitric acid equilibrium between the phases suitable for incorporation in process models of e.g. the innovative SANEX process. For the nitric acid / octanol / diluent system it was found that an accurate prediction of nitric acid distribution could be achieved using a model allowing 1:1, 1:2 and 1:3 nitric acid / octanol adducts. For the nitric acid / TODGA / diluent system the best models were found to be those allowing 4:1, 3:1, 2:1, 1:1 and 2:2 nitric acid / TODGA adducts. Superimposing the models for nitric acid distribution into the individual extractants and comparing with experimental results for the nitric acid / octanol / TODGA system showed systematic differences indicative of antagonistic and synergistic effects applying in the ranges 0.5-1.5 mol/L HNO3 and > 1.5 mol/L HNO3 respectively. These effects were modelled by the inclusion of 0:1:2, 1:1:1, 2:1:3 and 3:1:2 nitric acid / TODGA / octanol adducts. The effect of temperature on nitric acid extraction was well described by an Arrhenius type expression with an activation energy of −25.7 kJ/mol. No diluent dependence was found for nitric acid extraction.

Extraction of Nitric Acid, Americium(III), Curium(III), and Lanthanides(III) into DMDOHEMA Dissolved in Kerosene

“…Similar to other neutral extracting agents, [59][60][61][62][63][64][65][66][67] DMDOHEMA in TPH extracts significant amounts of nitric acid. Figure 2 shows the amount of nitric acid extracted as a function of initial aqueous nitric acid concentration (initial concentration is reported to represent nitric acid extraction for given experimental conditions, i. e. initial nitric acid and DMDOHEMA concentrations).…”

Effect of diluent on the extraction of europium(iii) and americium(iii) with N,N,N′,N′-tetraoctyl diglycolamide (TODGA)

“…The family of diglycolamides are known extracting agents for trivalent lanthanides and actinides in solvent extraction, with expected application in partitioning and transmutation of a nuclear fuel [22][23][24][25] and in radiopharmaceutical industry for 225 Ac production. [26][27][28][29] While the behavior of diglycolamides with respect to equilibrium distribution ratios, acid extraction and kinetics was extensively evaluated, [30][31][32][33][34][35][36][37][38][39][40][41][42] the effect of the diluent on the extraction was evaluated only in a few studies. [42][43][44][45][46][47] From the available data, correlations of diluent properties against the distribution ratios seems rather difficult.…”

Solvent extraction of An(III) and Ln(III) using TODGA in aromatic diluents to suppress third phase formation

“…1 La e DGA e e ed efficie e ac ac i ide a d a ha ide i f i ic acid i i he c e f adi c ide e a a i a d ac i ide ec c i g a egie . [2][3][4][5][6][7][8] H d hi ic DGA 9-10 a e ed a a ki g age (h di g back e a i i he a e ha e d i g e ac i ) a d i i g age (back e ac i g e a i f a aded ga ic ha e). [11][12][13][14] C ec e ce e i g DGA e ac i g age (N,N,N ,N -tetra-n-octyl-3-oxapentanediamide (TODGA, Figure 1) or N,N,N ,N -tetra-(2-ethylhexyl)-3oxapentanediamide, TEHDGA) ha e cce f bee e f ed i ab a ca e e i e .…”

“…U i g a e 1-c a di e e i ig ifica c -e ac i f i ic acid b he di e , 35 i addi i he i ic acid e ac ed b he DGA. 6,[36][37][38] Addi g a difie a c ica e e c ea -d e he i c ea ed be f c i e each f i g a i deg ada i d c d e h d i a d adi i .…”

“…Addi a c ide i g he (TODGA)2 (HNO3) add c a ed f i g -c di i a e ac i c a f a h ee add c b e ed i c ide ab e de ia i f i i ia i ic acid c ce a i i he a ge f 1 3 /L. Ce ai , a e hi ica ed de ( ee e. g. efe e ce6 ) igh ie d be e ag ee e i h he e e i e a da a. H e e , he a he i i ed e f da a a ai ab e…”