Effect of TBP on Extraction of REE and TPE with 4d Element Salts of Dibutylphosphoric Acid

Shmidt, O. V.; Zilberman, B. Ya.; Fedorov, Yu. S.; Palenik, Yu. V.; Glekov, R. G.; Sukhareva, S. Yu.

doi:10.1023/b:rach.0000015757.33382.86

“…Later, Weaver [2] demonstrated that Zr(NO 3 ) 2 (A) 2 (HA) 2 is formed in the extract, and at a greater HDBP excess ZrA 4 (HA) 4 is extracted from 1 -1.5 mol/L HNO 3 [3] while at the deficiency of HDBP Zr(NO 3 ) 2 A 2 is formed [4]. It was also found, that complex acidic Zr salts with alkyl phosphoric acids, including HDBP [5], have strong extraction ability towards rare earths (RE), transplutonium elements (TPE) and strontium [2].…”

Section: Introductionmentioning

confidence: 99%

The influence of dibutyl phosphoric acid on zirconium extraction with diluted tributyl phosphate and the role of uranyl nitrate

Blazheva

¹

,

Fedorov

²

,

Zilberman

³

et al. 2006

Czech J Phys

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Distribution coefficients of zirconium (D Zr ) in the 30% TBP -aqueous HNO 3 solution extraction system rise 1000-2000 times with the increase of the dibutyl phosphoric acid (HDBP) concentration from 0 to 0.01-0.08 mol/L. A solvate with the molar ratio Zr: HDBP = 1 was found by IR spectroscopy and analytic methods in the initial range of HDBP concentration. In the presence of U(VI) D Zr decreases with the growing U concentration, however, the ratio of Zr distribution coefficient in the presence of HDBP (D AZr ) to D Zr determined in its absence, R Zr = D Azr /D Zr , is rather high. Function of enhancement (F) was introduced for the evaluation of simultaneous influence of U and HDBP on Zr extraction. An increase of the U concentration resulted first in the decrease in F Zr , and then in its increase. The rising part of the F Zr curve was more noticeable at a molar excess of Zr over HDBP. The mechanism of Zr extraction by 30% TBP solution in the presence of HDBP when Zr is in excess to HDBP indicates the formation of the solvate with the ratio Zr: HDBP = 1; in the presence of U(VI) the complex with the same ratio is formed by the HDBP interaction with U in the system with a great excess of both HDBP and Zr.

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“…Precipitation of Zr -HDBP compounds does not occur in this case [3,6,7]. Precipitation of Zr -HDBP compounds does not occur in this case [3,6,7].…”

Section: Introductionmentioning

confidence: 99%

The influence of dibutyl phosphoric acid on zirconium extraction with diluted tributyl phosphate and the role of uranyl nitrate

Blazheva

¹

,

Fedorov

²

,

Zilberman

³

et al. 2006

Self Cite

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Distribution coefficients of zirconium (D Zr ) in the 30% TBP -aqueous HNO 3 solution extraction system rise 1000-2000 times with the increase of the dibutyl phosphoric acid (HDBP) concentration from 0 to 0.01-0.08 mol/L. A solvate with the molar ratio Zr: HDBP = 1 was found by IR spectroscopy and analytic methods in the initial range of HDBP concentration. In the presence of U(VI) D Zr decreases with the growing U concentration, however, the ratio of Zr distribution coefficient in the presence of HDBP (D AZr ) to D Zr determined in its absence, R Zr = D Azr /D Zr , is rather high. Function of enhancement (F) was introduced for the evaluation of simultaneous influence of U and HDBP on Zr extraction. An increase of the U concentration resulted first in the decrease in F Zr , and then in its increase. The rising part of the F Zr curve was more noticeable at a molar excess of Zr over HDBP. The mechanism of Zr extraction by 30% TBP solution in the presence of HDBP when Zr is in excess to HDBP indicates the formation of the solvate with the ratio Zr: HDBP = 1; in the presence of U(VI) the complex with the same ratio is formed by the HDBP interaction with U in the system with a great excess of both HDBP and Zr.

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“…Being a strong competing proton acceptor, it breaks HDBP dimers in the organic phase and prevents both the formation of HDBP ZS and the manifestation of its acid properties [24,25]. In addition, HBP extracts from the aqueous phase appreciable amounts of HNO 3 : with 30% TBP in a diluent (~1 M), the content of HNO 3 in the organic phase reaches 0.22 M, compared to 0.06 M without TBP [16,22].…”

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confidence: 96%

Extraction of molybdenum from nitric acid solutions with solutions of dibutyl hydrogen phosphate zirconium salt

Голецкий

¹

,

Zilberman

²

,

Fedorov

³

et al. 2012

Radiochemistry

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The extraction of Мо with a solution of dibutyl hydrogen phosphate (HDBP) zirconium salt (ZS) in xylene and in TBP-xylene and TBP-decane mixtures was studied in comparison with the Mo extraction in similar systems without Zr. The Mo extraction is enhanced to the largest extent (by a factor of 7 with 1.5 M HNO 3 ) at the HDBP : Zr ratio of 12, but the majority of experiments were performed at the ratio HDBP : Zr = 9, characteristic of the extraction of TPE and REE. The plots of D Mo vs. HNO 3 concentration in all the cases pass through a minimum at ~3 M HNO 3 , and the minimum is the deeper, the higher the TBP concentration. At the same time, in the system with HDBP ZS at the TBP concentration in the solvent exceeding 50%, further decrease in D Mo is not observed. The dependence of the Mo distribution ratio D Mo on the HDBP concentration at a fixed ratio HDBP : Zr = 9, the composition of the saturated systems, and the spectra of the saturated and unsaturated (with respect to Mo) systems suggest formation of mixed HDBP-Zr-Mo complexes. Assumptions concerning their composition and structure were made. According to the IR data, in these complexes in the absence of TBP the nitrate ion is not coordinated to the Mo atom. Bridged structures Мо-О-Мо are not formed either. Addition of TBP leads to a decrease in D Мо in the extraction with HDBP ZS, but, at the same time, the slope of the dependence of D Mo on the HDBP concentration increases, and the limiting capacity of the solvent for Mo also somewhat increases. These effects are primarily attributed to an increase in the HNO 3 concentration in the organic phase in the presence of TBP.The use of dialkyl hydrogen phosphate zirconium salts (HDAP ZSs) for partitioning of long-lived radionuclides of transplutonium (TPE) and rare earth (REE) elements and Sr is known for a relatively long time [1-3], but the extraction behavior of Mo was not examined in these studies.In our papers on TPE and REE partitioning, it was suggested to use acidic zirconium salt of dibutyl hydrogen phosphate (HDBP ZS) as TBP-compatible extractant, because HDBP is the first product of TBP degradation and is removed by washing the extractant with a Na 2 CO 3 solution. It was suggested to use a 0.2 M solution of HDBP ZS (HDBP : Zr = 9) in 30% TBP in paraffin hydrocarbons [4][5][6][7][8][9][10][11]. However, the Mo extraction with HDBP ZS solution was given less attention in these papers, compared to the extraction of REE and TPE, and the data we obtained previously [6-8, 12, 13] are insufficient for understanding the extraction behavior of Мо. For this purpose, it is necessary to study systematically the role of various components of the system in the extraction, including the role of TBP.The latter fact made it necessary to perform additional studies on the Mo extraction with HDBP ZS solutions in xylene and in 30% TBP/xylene. The results of these studies are discussed below together with data for the system HDBP ZS-30% TBP/decane. This paper is a part of a cycle of papers on the Mo extraction from nitri...

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Effect of TBP on Extraction of REE and TPE with 4d Element Salts of Dibutylphosphoric Acid

Cited by 3 publications

References 1 publication

The influence of dibutyl phosphoric acid on zirconium extraction with diluted tributyl phosphate and the role of uranyl nitrate

The influence of dibutyl phosphoric acid on zirconium extraction with diluted tributyl phosphate and the role of uranyl nitrate

The influence of dibutyl phosphoric acid on zirconium extraction with diluted tributyl phosphate and the role of uranyl nitrate

Extraction of molybdenum from nitric acid solutions with solutions of dibutyl hydrogen phosphate zirconium salt

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