Uranium oxalate

Oxo Ion Salts. Salts of 0x0 anions, such as nitrate, sulfate, perchlorate, iodate, hydroxide, carbonate, phosphate, oxalate, etc, are important for the separation and reprocessing of uranium, hydroxide, carbonate, and phosphate ions are important for the chemical behavior of uranium ia the environment (150—153). 

Sulphuric acid is not recommended, because sulphate ions have a certain tendency to form complexes with iron(III) ions. Silver, copper, nickel, cobalt, titanium, uranium, molybdenum, mercury (>lgL-1), zinc, cadmium, and bismuth interfere. Mercury(I) and tin(II) salts, if present, should be converted into the mercury(II) and tin(IV) salts, otherwise the colour is destroyed. Phosphates, arsenates, fluorides, oxalates, and tartrates interfere, since they form fairly stable complexes with iron(III) ions the influence of phosphates and arsenates is reduced by the presence of a comparatively high concentration of acid. 

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. 

Thorium metal, 24 759-761 in alloys, 24 760-761 preparation of, 24 759-760 properties of, 24 760-761 reactions of, 24 761 Thorium nitrate, 24 757, 766 Thorium oxalates, 24 768-769 Thorium oxide, 21 491 Thorium oxides, 24 757, 761-762 Thorium oxyhalides, 24 762 Thorium perchlorate, 24 764 Thorium phosphates, 24 765-766 Thorium pnictides, 24 761 Thorium sulfate, 24 764 Thorium-uranium fuel cycle, 24 758-759 Thorocene, 24 772 Thorotrast, 24 775-776 3A zeolite. See Zeolite 3A Three-boiling beet sugar crystallization scheme, 23 463-465 Three-color photography, 19 233-234 3D models, advantages of, 19 520-521 3D physical design software, 19 519-521 3D QSAR models, 10 333. See also QSAR analysis... 

The purification of uranium by precipitation may involve the formation of insoluble oxalate or peroxide complexes.50 In the oxalate method the ore concentrate is dissolved in nitric acid to give a uranyl nitrate solution from which uranyl oxalate is precipitated according to equation (101), leaving the bulk of the impurities in solution. This approach is favoured over dissolution in hydrochloric acid and reduction to UIV prior to U(C204)2 precipitation since it is simpler and... 

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. 

Total tetravalent uranium may be precipitated as an insoluble oxalate or fluoride (Grinberg et at., 1957) or in trace amounts co-precipitated for example with neodymium fluoride (cf. Pu ). Such a procedure can be used to show whether uranium is present in the lower oxidation state, for example, in anoxic waters because hexavalent uranium does not co-precipitate in this way. 

Uranium(VI) dioxydichloride, 5 148 Uranium (VI) hydrogen dioxyortho-phosphate 4-hydrate, 6 150 analysis of, 5 151 Uranium(IV) oxalate, 3 166 Uranium (IV) oxide, formation of, by uranyl chloride, 6 149 Uranium (IV) (VI) oxide, U3Oa, formation of, by uranyl chloride, 5 149... 

In third separation, thorium is retained on a cation-exchange resin while uranium is eluted from the resin column. Thorium is then eluted as an oxalate complex and evaporated on a planchet for counting. The planchet is flamed to volatilize the oxalic acid and then counted. 

Principle of Separation. Uranium as the U02+ ion in strong chloride solutions forms an anionic chloride species such as U02C13 thorium does not. If a solution in which the chloride ion has been adjusted to form the uranyl chloride complex is passed through a cation exchange column, the uranium passes through the column and cationic Th+4 is absorbed. After the column is washed to insure that no uranium remains, the absorbed thorium is complexed with oxalate ions to form an anion and is released from the column. Although thorium generally is precipitated with oxalate ions, with excess quantities of oxalate it forms a soluble anionic species. The mass of thorium in this experiment is extremely low relative to that of oxalate and will not form a precipitate. 

Step 8. Evaporate 10 ml 0.5 M oxalic acid to about 2 mL and pour onto the second planchet with dried 100-A. sample of the initial uranium solution (see Part 7A, Step 5). Evaporate to dryness under the heat lamp. Flame the planchet as in Step 6. Count three times for 3,000 s each with proportional counter for alpha and beta particles. Record in Data Table 7.5... 

Data Table 7.5 Count rate of uranium solution with oxalic acid ... 

Evaluate the effect of beta-particle absorption in residual oxalic acid on the count rates of the initial uranium solution. 

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