Influence of the purity and irradiation stability of Cyanex 301 on the separation of trivalent actinides from lanthanides by solvent extraction

Abstract

The solvent extraction of trivalent actinides and lanthanides from aqueous 1M NaNO 3 by the sulfur containing acidic extractant Cyanex 301 was studied. This commercial extractant shows very interesting features for An(III)/Ln(III) separations depending on the purification of its main constituent bis(2,2,4-trimethylpentyl)dithiophosphinic acid. Efficient separations were observed with nonpurified Cyanex 301 for high Ln(III) concentrations, but not for low Ln(III) concentrations. Successful purification of Cyanex 301 was performed by precipitation of the ammonium dithiophosphinate. Very high An(III)/Ln(III) separation factors (higher than 103) were obtained for micro or macro concentrations of Ln(III) at pH 3 4.

Studies on the Separation of Minor Actinides from High-Level Wastes by Extraction Chromatography Using Novel Silica-Based Extraction Resins

“…It is known that these oxygen-containing organophosphoric compounds show high adsorbability for Ln~III!. 18,25,26 These separation experiments demonstrated that Am~III! can be effectively separated from a macro amount of Ln~III!…”

“…compared to trivalent lanthanides, and the results agreed well with those reported in liquidliquid extraction. 16,18 On the other hand, the previous experiments indicated that 244 Cm~III! can also be extracted by purified Cyanex 301 and showed an extraction behavior similar to Am~III!~Ref.…”

“…b From Asahi Chemical Industry. described, 18,19 and the purity of the Cyanex 301 obtained was 99.5%. The impregnation procedure of the extractants into the SiO 2 -P particles is as follows: ;5 to 7 g of an extractant~CMPO, HDEHP, or Cyanex 301!…”

“…Since it has been reported that purified Cyanex 301 shows low stability due to oxidation and decomposition, 18,25,26 we have conducted a separation experiment using an "aged" Cyanex 3010SiO 2 -P to examine the effect of this on the separation performance. Figure 9 illustrates the experimental results for the same sample solution as utilized in the experiment of Fig.…”

Synthesis and evaluation of potential ligands for nuclear waste processing

“…61 Repetition of the extraction experiments after two days and after 15 days showed a gradual decrease in SF values, which corresponds to gradual decomposition of CYANEX 301. Similar results were obtained by Hill et al 62 when the extraction experiments were carried out using synergistic mixtures (CYANEX 301 and TBP).…”