Increasing the recovery and selectivity of 238 U, 235 U, and 234 U extraction with tri-n-butyl phosphate in mine tailing samples with a high copper content.

Autor: Expósito-Suárez VM; CIEMAT, Avenida Complutense 40, 28040, Madrid, Spain., Suárez-Navarro JA; CIEMAT, Avenida Complutense 40, 28040, Madrid, Spain. Electronic address: ja.suarez@ciemat.es., Aguado-Herreros CM; IES Virgen de la Paloma, 28039, Madrid, Spain., Sanz MB; CIEMAT, Avenida Complutense 40, 28040, Madrid, Spain., Suárez-Navarro MJ; Universidad Politécnica de Madrid (UPM), E.T.S.I. Caminos, Canales y Puertos, Professor Aranguren s/n, 28040, Madrid, Spain., Caro A; CIEMAT, Avenida Complutense 40, 28040, Madrid, Spain.
Jazyk: angličtina
Zdroj: Analytica chimica acta [Anal Chim Acta] 2023 Jun 08; Vol. 1259, pp. 341183. Date of Electronic Publication: 2023 Apr 07.
DOI: 10.1016/j.aca.2023.341183
Abstrakt: Abandoned Cu mine tailings may be associated high concentrations of U. However, the presence of stable cations such as Cu, Fe, Al, Ca, or Mg, etc. in high concentrations can reduce the chemical efficiency of the liquid-liquid extraction method with tri-n-butyl phosphate (TBP); it can also inhibit the electrodeposition of U on the stainless steel planchet where the sample is measured. In this work we studied an initial stage of complexation with ethylenediaminetetraacetic acid (EDTA) and a back extraction with different solutions: H 2 O, Na 2 CO 3 , and (NH 4 ) 2 CO 3 at room temperature and at 80 °C. The sensitivity of the method was 4.9·10 -4 Bq for 238 U and 234 U, and 2.3·10 -5 Bq for 235 U. The validation of the method achieved 95% of the results when using a |ζ-score| ≤ ± 2.0 and a relative bias (RB[%]) ≤ ± 20% as the acceptance criteria. The recoveries obtained with the proposed method were higher than those achieved with the extraction method without initial complexation and re-extraction with H 2 O for water samples. Finally, this method was applied in practice to study the tailing of an abandoned Cu mine and the activity concentrations of 238 U and 235 U were compared with those obtained by gamma spectrometry for 234 Th and 235 U. The means and variances of both methods showed no significant differences between these two isotopes.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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