Levextrel

The only major impediment to the development of SIRs on an industrial hydrometallurgical scale is the problem of leakage of the reagent from the resin phase into the aqueous feed solution, a problem that is more severe in the first type of SIRs than in the Levextrel resins. If this problem can be solved, a bright future is predicted for this concept in resin technology. 

This study was carried out in order to evaluate the applicability of extraction chromatography, with TBP as the extracting agent, instead o anion exchange for efficient purification of plutonium from Am (18,19). The resin used was Levextrel-TBP, a product of Bayer AG, Leverkusen, Germany. The Levextrels are styrene - divinylbenzene - based resins which are copolymerized... 

For technical applications, knowledge of the irradiation behaviour of the Levextrel-TBP resin is important. A detailed study carried out at the Radiochemistry Institute of the Technical University, Munich(21,22), showed that with gamma irradiation the formation rate of dibutyl phosphoric acid (HDBP) and of "non-removable" acidic radiolysis products ("do-bads") is 2 to 5 times lower with Levextrel-TBP resin than with pure TBP the effect is attributed to the "scavanger" action of the aromatic groups in the matrix material. In summary, a high radiation resistance of the resin has become evident. 

The final separation of Am and Cm from RE can be done by applying the solvent extraction techniques developed in the HDEHP and TBP flow-sheets. As an alternative, partitioning techniques based on column extraction chromatography (LEVEXTREL-TBP and LEVEXTREL-HDEHP) are being experimentally studied on fully active HAW solutions. A final decision on the techniques for the actinide/RE separation will be reached at a later stage of the programme. 

LEVEXTREL resin in the HDEHP form (Bayer, Leverkusen, FRG) was used as stationary phase and two columns were utilized to remove Pu and Am-Cm-RE from the respective acidic and low-acidity feed solutions. More than 99% of Pu was adsorbed and eluted from the first chromatographic column by oxalic acid, whereas less satisfactory results were obtained for the Am, Cm/RE separation tests, fractions of Am and Cm as high as a few percent being carried over into the RE fraction. 

Extraction ofZn(II), Cu(II), and Cd(II) with Impregnated Resins and Levextrel Resins Containing Acidic Organophosphorus Compounds (DEHPA, DTMPPA)... 

Cortina et al [31,32,34,35] studied the distribution of divalent metal ions [Zn(II), Cu(II) and Cd(II)] with impregnated resins and Levextrel resins containing acidic organophosphorous compounds (HL). Metal distribution ratio of these metal ions are shown in Figures 12—15. 

Figure 14 Metal distribution values of Zn, Cu, or for Levextrel resins containing DTMPPA (Lewatit TP807 84). (From Ref. 35.)...

Metal extraction studies on Levextrel 807 84 resins indicated higher selectivity factors for the extraction of both metals in comparison with the chelating resins mentioned above. This is due to the fact that the functional groups fixed onto the polymer chains cannot always reach favorable posi-... 

FigureSl Distribution ratio of cobalt (II) (empty symbols) and nickel (II) (filled symbols) from nitrate (circles) and sulfate (squares) solutions with Levextrel 807 84 resins. (From Ref. 12.)...

Cortina et al. [6,18,32] studied the efficiency of impregnated resins containing the active component of Cyanex 272 adsorbed onto Amberlite XAD2 for the extraction of Zn(II), Cu(II), and Cd(II) from dilute solutions in nitrate and chloride media. The metal distribution studies show, as described in Sect. III.B, that the extraction of these metal ions involves reactions similar to those in solvent extraction systems. The extraction results indicate that Zn(Il) is adsorbed more selectively than Cu(II) and Cd(II), making possible the quantitative separation of Zn(II) from the other two [6], No significant differences were found on comparison of the extraction efficiency of these resins with Levextrel 807 84 resins [35]. 

Keywords Extraction Chromatography, Levextrel Resins, Ni-Co Separation, High Purity... 

In the study about purifying cobalt solution with the extraction chromatography, Yo-shizuka et. al [14] used levextrel resin with Cyanex272 to separate Co( II) from Ni( II) in nitrate and sulfate medium, meanwhile, the behaviors of various metal ions in the resin were studied. Zhou... 

Chunshan, Wangyan et. al [15, 16] used P204,the transformed levextrel resin to separate Co from Cu, Sn, Mn, Zn, Fe and other metal ions. 

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