Flowsheet oxalates

Conceptual Flowsheet for the Extraction of Actinides from HLLW. Figure 5 shows a conceptual flowsheet for the extraction of all the actinides (U, Np, Pu, Am, and Cm) from HLLW using 0.4 M 0< >D[IB]CMP0 in DEB. The CMPO compound was selected for this process because of the high D m values attainable with a small concentration of extractant and because of the absence of macro-concentrations of uranyl ion. Distribution ratios relevant to the flowsheet are shown in previous tables, IV, V, VI, and VII and figures 1 and 2. One of the key features of the flowsheet is that plutonium is extracted from the feed solution and stripped from the organic phase without the addition of any nitric acid or use of ferrous sulfamate. However, oxalic acid is added to complex Zr and Mo (see Table IV). The presence of oxalic acid reduces any Np(VI) to Np(IV) (15). The presence of ferrous ion, which is... 

A depressant system developed for beneficiation of Ta/Nb-Zr ores involves oxalic acid-hydro fluoro silicic acid and depressant SHQ. SHQ is a mixture of a low-molecular-weight acrylic acid and condensation product of disulphonic acid (Suspendol PKK, manufactured by Cognis, Germany). After the development of the final reagent scheme, a series of locked-cycle tests were performed using the flowsheet shown in Figure 23.7. 

The second flowsheet was therefore implemented in 24 stages (Figure 3.13) (177). This time, the An(III) + Ln(III) product solution contained only 0.66% Sr and 1.31% Mo. However, the large amounts of oxalic acid (up to 0.4 M) introduced in the feed and scrubbing solutions to avoid Zr extraction led to partial precipitation of An(III) and Ln(III) oxalates in the low acidity conditions of the stripping section. 

Thanks to these promising results, two hot tests were further carried out in the hot cells of the ITU (181, 182) on a genuine highly active PUREX raffinate obtained by reprocessing 500 g of a U02 commercial reactor spent fuel (60 GWd/t). Oxalic acid and HEDTA were added to the PUREX high-activity raffinates, and its acidity was adjusted to 4.4 M. The flowsheet tested was... 

Figure 3. Equipment flowsheet for continuous precipitation of lanthanide oxalates...

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