Plutonium oxalate

Plutonium nitride, 19 691 Plutonium oxalates, 19 691 Plutonium(IV) oxide, 19 669 Plutonium oxides, 19 688-689 Plutonium oxyhalides, 19 689-690 Plutonium pnictides, 19 691 Plutonium-producing reactors, storage of radioactive waste from, 25 855 Plutonium radioisotopes, 21 319 Plutonium refractory compounds, 19 687 Plutonium reprocessing plants, 19 686 Plutonium silicides, 19 690-691 Plutonium solutions, self-radiolysis of, 19 694... 

Plutonium was stripped from the solvent with hydroxylamine, concentrated further by cation exchange, precipitated as plutonium oxalate, and calcined to the oxide. 

During plutonium reconversion in a reprocessing plant, oxalate supernatant is normally generated during plutonium precipitation by oxalic acid as plutonium oxalate. This is further converted into plutonium oxide. This waste solution will have the following composition uranium (U) 5 gm dm , plutonium (Pu) 25 mg dm, mthenium (Ru ° ) 0.0032 mCi dm, cesium (Cs ) 0.003 mCi dm , nitric acid 3 M, and H2C2O4 0.1 M. 

In their manufacture uranium(IV) oxide is mixed with the appropriate quantity of plutonium(IV) oxide, the mixture pressed into pellets and then sintered (termed coprocessing in the USA). Uranium(IV) oxide is produced by one of the above-described processes and plutonium(IV) oxide from the aqueous nitrate solution produced during reprocessing by precipitating it as plutonium oxalate and calcining the oxalate. 

Another procedure extensively used for the preparation of plutonium trichloride is the reaction of plutonium oxalate with hydrogen chloride. 

Precipitation of plutonium oxalate by adding oxalic acid ... 

Oxalates. Precipitation of plutonium oxalate from dilute acidic solution... 

Plutonium. The plutonium nitrate product must be converted to MO fuel if it is to be recycled to lightwater reactors. Whether from a plutonium nitrate solution or a mixed U/Pu nitrate solution, the plutonium is typically precipitated as the oxalate and subsequendy calcined to the oxide for return to the fuel cycle (33). 

The plutonium extracted by the Purex process usually has been in the form of a concentrated nitrate solution or symp, which must be converted to anhydrous PuF [13842-83-6] or PuF, which are charge materials for metal production. The nitrate solution is sufficientiy pure for the processing to be conducted in gloveboxes without P- or y-shielding (130). The Pu is first precipitated as plutonium(IV) peroxide [12412-68-9], plutonium(Ill) oxalate [56609-10-0], plutonium(IV) oxalate [13278-81-4], or plutonium(Ill) fluoride. These precipitates are converted to anhydrous PuF or PuF. The precipitation process used depends on numerous factors, eg, derived purity of product, safety considerations, ease of recovering wastes, and required process equipment. The peroxide precipitation yields the purest product and generally is the preferred route (131). The peroxide precipitate is converted to PuF by HF—O2 gas or to PuF by HF—H2 gas (31,132). 

Oxalates. Stable oxalates of Pu(III), Pu(IV), and Pu(VI) are known. However, only the Pu(III) and Pu(IV) oxalates are technologically important (30,147). Brilliant green plutonium(III) oxalate [56609-10-0] precipitates from nitric acid solutions containing Pu(III) ions upon addition of oxaUc acid or sodium oxalate. The composition of the precipitate isPu2(C20 2 10H2O. A homogeneous oxalate precipitation by hydrolysis of diethyl oxalate at... 

C minimises plutonium loss ia the filtrate and decreases filtering time (166). Heating the compound to ca 270°C ia air or to 460°C ia absence of air results ia the formation of PUO2. Yellow-green Pu(IV) oxalate [26588-74-9] Pu(C20 2 6H20, precipitates from acidic solutions of Pu(IV) upon addition... 

On the basis of these facts, it was speculated that plutonium in its highest oxidation state is similar to uranium (VI) and in a lower state is similar to thorium (IV) and uranium (IV). It was reasoned that if plutonium existed normally as a stable plutonium (IV) ion, it would probably form insoluble compounds or stable complex ions analogous to those of similar ions, and that it would be desirable (as soon as sufficient plutonium became available) to determine the solubilities of such compounds as the fluoride, oxalate, phosphate, iodate, and peroxide. Such data were needed to confirm deductions based on the tracer experiments. 

The complete chemistry of plutonium 1 iquid-to-solid conversion processes, especially peroxide and oxalate precipitation, should be further studied. Research and development of direct thermal denitration methods should also be pursued. 

Precipitation Processes. Plutonium peroxide precipitation is used at Rocky Flats to convert the purified plutonium nitrate solution to a solid (14) the plutonium peroxide is then calcined to Pu02 and sent to the reduction step. The chemistry of the plutonium peroxide precipitation process is being studied, as well as alternative precipitation processes such as oxalate, carbonate, fluoride, and thermal denitration. The latter method shows the most promise for cost and waste reduction. 

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... 

All of die halides except tile hexafluoride and the triiodide may be prepared by the hydrohalogenation of rhe dioxide or of the oxalate of plutonium(lll) at a temperature of about 700°C. With hydrogen fluoride the reaction product is PUF4, unless hydrogen is added to the gas stream, in which case the trifluoride is produced. With hydrogen iodide the reaction product is PuOi, and the other oxyhalides may be formed by the addition of appropriate quantities of water vapor to the hydrogen halide gas. Plutonium triiodide is produced by the reaction of the metal with hydrogen iodide at about 400°C. The hexafluoride is produced by direct combination of the... 

Mohapatra, P.K. Ruikar, P.B. Manchanda, V.K. Recovery of plutonium from oxalate supernatant using l-phenyl-3-methyl-4-benzoyl-5-pyrazolone, J. Radioanal. Nucl. Chem. 270 (2006) 345-348. 

Mapara, P.M. Godbole, A.G. Swarup, R. Nagar, M.S. Extraction of uranium and plutonium from oxalate bearing solutions using phosphonic acid Solvent extraction, extraction chromatography and infrared studies, J. Radioanal. Nucl. Chem. 240 (1999) 631-635. 

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