Thermodynamic modeling of solvent extraction systems: Successes and problems

Journal Article · · Separation Science and Technology; (United States)

DOI:https://doi.org/10.1080/01496399108050540· OSTI ID:5517196

Jarvis, N V ^[1]

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1. Atomic Energy Corp. of South Africa Ltd., Pretoria (South Africa)

Recent approaches to thermodynamic modeling of solvent extraction systems are applied to nitric acid and AM(III) extraction by dihexyl-N, N-diethylcarbamoylmethyl phosphonate in CCl{sub 4}. 1:1 and 2:1 complexes were found to form in the organic phase for nitric acid extraction with {bar K}{sub 1} = 0.125 {plus minus} 0.00154 and {bar K}{sub 2} = 1.41 {times} 10{sup {minus}5} {plus minus} (2.60 {times} 10{sup {minus}7}). Extraction of nitric acid was also followed by IR spectrophotometry which verified the results obtained. Modeling of Am(III) extraction up to an initial aqueous nitric acid concentration of 4 M yielded good results. Extraction constants for species forming in the organic phase were found to be K{sub ex{sub 0}} = 38.6 {plus minus} 30.4 for (Am(No{sub 3}){sub 3}{times}E{sub 3}){sub 0}, K{sub ex{sub 1}} = 7.43 {plus minus} 0.572 for (Am(NO{sub 3}){sub 3}{times}E{sub 2}{times}(E{times}HNO{sub 3})){sub 0} and K{sub ex{sub 2}} = 1.04 {plus minus} 0.0281 for (Am(NO{sub 3}){sub 3} {times} E {times} (E {times} HNO{sub 3}){sub 2}){sub 0}. Problems encountered are highlighted and discussed, improvements to modeling approaches are suggested, and results obtained are critically discussed and compared to the literature.

• OSTI ID: 5517196
• Journal Information: Separation Science and Technology; (United States), Journal Name: Separation Science and Technology; (United States) Vol. 26:10-11; ISSN SSTED; ISSN 0149-6395
• Country of Publication: United States
• Language: English

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