Oxidation of Urea with Nitrous Acid in Nitric Acid Solutions

2005 ◽  
Vol 47 (1) ◽  
pp. 58-62 ◽  
Author(s):  
K. N. Dvoeglazov ◽  
V. I. Marchenko
Keyword(s):  
Nitric Acid ◽  
Nitrous Acid ◽  
Acid Solutions ◽  
Nitric Acid Solutions

The Effect of NO, HNO2 and HNO3 On Corrosion of Stainless Steel by H2SO4★

CORROSION ◽  
1958 ◽  
Vol 14 (1) ◽  
pp. 27-30
Author(s):  
W. P. McKINNELL ◽  
L. F. LOCKWOOD ◽  
R. SPEISER ◽  
F. H. BECK ◽  
M. G. FONTANA
Keyword(s):  
Nitric Oxide ◽  
Stainless Steel ◽  
Nitric Acid ◽  
Nitrous Acid ◽  
Acid Solutions ◽  
Active Type ◽  
Nitrate Ions ◽  
Nitric Acid Solutions ◽  
Spot Tests

Abstract Earlier work by other investigators has shown that nitrous acid is involved in the passivation of iron in concentrated nitric acid solutions. This paper describes the effect of nitric oxide, HNO2 and HNO3 on the corrosion of active Type 302 stainless steel by 10 percent H2SO4. Specimens of Type 302 stainless steel, activated by abrading on 240 grit emery cloth and exposed to 10 percent H2SO4 solutions, were passivated by bubbling nitric oxide through the solution. Bubbling oxygen through the solution did not passivate these abraded specimens. Abraded specimens exposed to an atmosphere of nitric oxide before immersion in nitric oxide-free H2SO4 remained active. Spot tests of 10 percent H2SO4 treated with nitric oxide revealed the presence of nitrite and nitrate ions in the solution. The addition of one part of 10 percent HNO3 to 60 parts of 10 percent H2SO4 was found to produce passivity of abraded stainless steel specimens exposed to the solution. 4.3.2

scholarly journals Neptunium extraction by N,N-dialkylamides

2020 ◽  
Vol 108 (9) ◽  
pp. 707-716
Author(s):  
Jarrod M. Gogolski ◽  
Peter R. Zalupski ◽  
Travis S. Grimes ◽  
Mark P. Jensen
Keyword(s):  
Nitric Acid ◽  
Solvent Extraction ◽  
Radioactive Waste ◽  
Partial Oxidation ◽  
Acid Solutions ◽  
Nitric Acid Solutions ◽  
Organic Solutions

AbstractSeparation of neptunium by solvent extraction has been based on tributylphosphate (TBP) for decades, but TBP is not fully incinerable, which adds to the burden of long-lived radioactive waste. Alternatives to TBP for uranium and plutonium extraction, such as the N,N-diakylamides, previously have been explored in the hopes of transitioning to an extractant that is incinerable. Four N,N-diakylamides, N,N-dihexylhexanamide (DHHA), N,N-dihexyloctanamide (DHOA), N,N-di(2-ethylhexyl)butanamide (DEHBA), and N,N-di(2-ethylhexyl)-iso-butanamide (DEHiBA) were considered in this work for their potential to extract millimolar concentrations of Np(IV), Np(V), and Np(VI) from nitric acid solutions into organic solutions containing 1 M extractant in Exxsol D60. Under these conditions the branching of the alkyl substituents affects the extractability of Np(VI) and Np(IV), causing three of the dialkylamides, DHHA, DHOA and DEHBA, to extract neptunium in the expected order Np(VI) > Np(IV) > > Np(V). In contrast, branched DEHiBA is so poor an extractant for Np(IV) that the extraction order becomes Np(VI) > > Np(V) > Np(IV) between 0.1 and 5.6 M HNO3 due to partial oxidation of the Np(V) in nitric acid.

Extraction of tetra- and hexavalent actinide ions from nitric acid solutions using some diglycolamide functionalized calix[4]arenes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rajesh B. Gujar ◽  
Parveen K. Verma ◽  
Prasanta K. Mohapatra ◽  
Mudassir Iqbal ◽  
Jurriaan Huskens ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Solvent Extraction ◽  
Extraction Efficiency ◽  
Minor Actinide ◽  
Acid Solutions ◽  
Extraction Mechanism ◽  
Nitrate Ion ◽  
Nitric Acid Solutions ◽  
Actinide Ions ◽  
Acid Extractant

Abstract Neptunium is one of the most important minor actinide elements with some of its isotopes having very long half-lives, therefore necessitating its separation from acidic radioactive wastes. Solvent extraction of Np4+ and NpO2 2+ was studied using three multiple diglycolamide (DGA) extractants with n-propyl, n-octyl and 3-pentyl substituents termed as L I , L II and L III , respectively, in a mixed diluent of 5% isodecanol and 95% n-dodecane. For comparison purpose, the extraction of Pu4+ and UO2 2+ was carried out under identical conditions. The extraction efficiency of the ligands for the tetravalent ions followed the trend: L II  > L I  > L III , which changed to L III  > L II  > L I for the hexavalent ions. While the extraction of the tetravalent ions was reasonably good (ca. 90–98%) with an extremely low (5.0 × 10−5 M) ligand concentration, poor extraction (ca. 5–16%) of the hexavalent ions was seen even with a 20 times higher concentration of the ligand. In general, Pu4+ was better extracted than Np4+, while NpO2 2+ was marginally better extracted then UO2 2+. A ‘solvation’ type extraction mechanism was proposed based on the extraction profiles obtained as a function of the concentrations of the feed nitric acid, extractant as well as nitrate ion. The extracted species were found out to be M(NO3)4·mL and MO2(NO3)2·nL (M = Np or Pu, 1 < m < 2, n ≃ 1).

Separation of Americium and Curium in Nitric Acid Solutions via Oxidation of Am(III) by Bismuthate and Perxenate Ions

2020 ◽  
Vol 62 (5) ◽  
pp. 581-586
Author(s):  
Yu. M. Kulyako ◽  
D. A. Malikov ◽  
T. I. Trofimov ◽  
S. A. Perevalov ◽  
K. S. Pilyushenko ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Acid Solutions ◽  
Nitric Acid Solutions
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