Polarographic Determination of Hexavalent Uranium in Uranium Dioxide

Motojima, Kenji; Hoshino, Akira

doi:10.3327/jaesj.2.1

Cited by 6 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The U03 content in the powder was calculated to be 4.84% by comparing the Coulomb under curve 1 with that under curve 2. This value agrees well with the value, 4.8%, obtained by polarography (7) and corresponds to the O/U ratio of 2.0456.…”

Section: Resultssupporting

confidence: 91%

“…For example, such dissolution can be attained by strong phosphoric acid (3) for iron, uranium, or plutonium compounds; by molten salt solutions of mixtures of aluminum chloride and potassium chloride (4) for actinide oxides; and by diluted sulfuric acid (5) for iron compounds. Dissolution of uranium oxide powder in strong phosphoric acid was employed for the polarographic (6)(7)(8) or the coulometric (3) determination of uranium(VI). However, no attempt has been reported for the determination of U(VI) distribution in a solid of uranium oxides.…”

Section: Determination Of Oxidation States Of Uranium In Uraniummentioning

confidence: 99%

“…Strong Phosphoric Acid. Reagent grade phosphoric acid was heated in a quartz flask under reducing pressure with the aid of a water-jet pump until the temperature of the acid rose to 300 °C (7). Uranium Oxide Samples.…”

Section: Determination Of Oxidation States Of Uranium In Uraniummentioning

confidence: 99%

See 2 more Smart Citations

Determination of oxidation states of uranium dioxide pellets by two-step flow-coulometry

Kihara¹,

Yoshida²,

Mizumoto³

et al. 1980

Anal. Chem.

View full text Add to dashboard Cite

1601identified with pH(S) in the operational definition of pH. Nevertheless, too little is yet known concerning the residual liquid-junction potential in these solvents at low temperatures to permit one to assess the internal consistency of the pH scale defined by these reference points. Measurements of pH under these extreme conditions are rendered difficult by the extraordinarily high resistance of the usual glass electrodes. In addition, modified reference electrodes will doubtless prove a necessity. LITERATURE CITED(1) M. Sankar, J. B. Macaskill, and R. G. Bates, J . Solution Chem., 8, 887 (1979) 0 Spivey and Shedlovsky 0 Present work 47T 0 10 2 0 30 wt X EIOH Figure 3. pK(molality scale) for acetic acid in ethanol/water mixtures at 0 and 25 OC as a function of the composition of the solvent. Data in water are from Ref. 6 and 7of pH measurements in ethanol/water media at temperatures below 0 "C. The values of PQH for the acetate and phosphate buffers given in Table I11 may fill this need. When used as reference solutions, the PQH of these buffer solutions is \ --I A chemical method for analysis of distribution of oxidation states of metals in solids has been developed as a reference to other methods based on physical measurements. A solid is dissolved with a continuous flow of strong phosphoric acid from surface to bulk, and oxidation states of the dissolved ions are determined consecutively by two-step flow-coulometry. Strong phosphoric acid dissolves such solids as uranium or iron oxides to Ions whose oxidation states are the same as those in solids. The oxidized surface of about 20 A on a UOz pellet which had stood for about 10 years at room temperature in alr was estimated to be U02.05, and the O/U ratio decreased toward the bulk until 0.1 pm. After the pellet was heated for 10 h at 300 or 430 O C in air, the oxidized surface layer increased to about 8 pm (400 8, of powdered U308 + UO,+,, 0.66 > x > 0.01) or about 820 pm (370 prn of powdered U308 -t 3 prn of U,08 + 450 pm of UOZ+,, 0.66 > x > 0.01), respectively.Analysis of oxidation states of metals in solids based on physical measurements gives abundant information on ma-terial science. These physical methods can be classified broadly into methods (1) for analysis of very thin layers at the surface such as by X-ray photoemission spectrometry (XPS) or Auger electron spectrometry (AES) and methods ( 2 ) which give overall information on a solid such as measurements of conductivity or electromotive force (EMF). There are many difficulties still remaining with these methods. In the former, for example, pretreatment of the surface and composition of the matrix greatly affect the result of analysis, and, in the latter, interaction between sample and electrode and the presence of impurities often give serious trouble. Therefore, calibration by reference materials and careful evaluation of data obtained are required. Obviously, data obtained by chemical analyses offer many suggestions for the interpretation of results obtained by physical methods.Although ...

show abstract

Section: Resultssupporting

confidence: 91%

Section: Determination Of Oxidation States Of Uranium In Uraniummentioning

confidence: 99%

See 1 more Smart Citation

Determination of oxidation states of uranium dioxide pellets by two-step flow-coulometry

Kihara¹,

Yoshida²,

Mizumoto³

et al. 1980

Anal. Chem.

View full text Add to dashboard Cite

show abstract

“…Quinine, 130-95-0; quinidine, 56-54-2; cinchonine, 118-10-5; cinchonidine, 485-71-2; atropine, 51-55-8; hysocyamine, 101-31-5; pilocarpine, 92-13-7; isopilocarpine, 531-35-1. LITERATURE CITED (1) Clarke, E. G. C. "Isolation and Identification of Drugs'1; The Pharmaceutical Press: London, 1978. methods. One of the chemical methods, which does not require reference material, is gravimetry (3,10), and the other is grounded on a principle that U02+x can be dissolved by some kinds of solvents such as strong phosphoric acid, SPA (3,(11)(12)(13), and the molten salts mixture of aluminum chloride and potassium chloride (14) producing uranium ions whose oxidation states are the same as those in the solid U02+x. The O/U ratio can be calculated from the amounts of U(IV) and U(VI) in the solution determined by spectrophotometry (15, 16), polarography (11)(12)(13), coulometry (17,18), or titrimetry (3,19).…”

mentioning

confidence: 99%

“…One of the chemical methods, which does not require reference material, is gravimetry (3,10), and the other is grounded on a principle that U02+x can be dissolved by some kinds of solvents such as strong phosphoric acid, SPA (3,(11)(12)(13), and the molten salts mixture of aluminum chloride and potassium chloride (14) producing uranium ions whose oxidation states are the same as those in the solid U02+x. The O/U ratio can be calculated from the amounts of U(IV) and U(VI) in the solution determined by spectrophotometry (15, 16), polarography (11)(12)(13), coulometry (17,18), or titrimetry (3,19).…”

mentioning

confidence: 99%