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Abstract  

The oxidation of Fe2+ in uranium leaching solutions with gaseous mixture of SO2 and air has been studied. The variables studied include H2SO4 concentration, temperature, SO2 concentration and time. The oxidation rate was founded to increase greatly with an increase in the solution temperature. The almost total oxidation of Fe2+ is readily achieved at 95 °C. By appropriately adjusting the temperature of solution and SO2/O2 in the gas, oxidation of ferrous ion and generation of sulphuric acid can be carried out. It was founded that solutions produced by such oxidation processing are very suitable for the uranium ore leaching.

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Abstract  

Reduction of U3O8 was investigated for the recycling of spent oxide fuel from a commercial nuclear power plant. The possible reduction methods were proposed and compared. Based on the thermodynamic analysis, Li metal was selected as a reductant. The optimum reaction temperature for the reduction of U3O8 was investigated at the wider reaction temperature range. The adverse oxidation of U metal by Li2O at 1,000 °C was experimentally verified. Ellingham diagram was constructed to investigate the extent of the uranium oxides reduction when the reaction was carried out above melting point of U metal.

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Appel, H. M. (1993) Phenolics in ecological interactions: the importance of oxidation. J. Chem. Ecol. 19 , 1521–1552. Appel H. M. Phenolics in ecological interactions: the

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Journal of Flow Chemistry
Authors:
Matthew Simmons
,
Charlotte Wiles
,
Vincent Rocher
,
M. Grazia Francesconi
, and
Paul Watts

; Hill , M. R. ; Harris , R. ; Muster , T. H. J. Magn. Magn. Mater . 2009 , 321 , 2677 – 2681 . 25. Cornell , R. M. ; Schwertmann , U. The Iron Oxides: Structure, Properties

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Introduction Mn oxide minerals are ubiquitous in soil and sediment [ 1 ]. Mn oxide is an important oxidant for high redox potential and acts as a catalyst for organic matter decomposition [ 2 ]. The catalytic activity of Mn

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Reaction Kinetics, Mechanisms and Catalysis
Authors:
Valeria Palermo
,
Ángel G. Sathicq
,
Patricia G. Vázquez
,
Horacio J. Thomas
, and
Gustavo P. Romanelli

variety of acid-catalyzed reactions such as esterification, etherification, olefin hydration, and dehydration of alcohols, and are also attractive as catalysts for oxidation processes [ 2 ]. Recently, we have used Keggin heteropolyacids in a range of

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Preparation of nanoparticles of oxides by the citrate–nitrate process

Effect of metal ions on the thermal decomposition characteristics

Journal of Thermal Analysis and Calorimetry
Authors:
S. Banerjee
,
A. Kumar
, and
P. Sujatha Devi

Introduction In recent years, there is a renewed interest in the preparation of nanoparticles of oxides due to their increasing demand in technological applications. For example, metal oxides such as ZnO, Fe 2 O 3 , and SnO 2

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Abstract  

Bismuth ferrite (BiFeO3) was obtained by a combustion reaction staring from two precursors systems, namely Fe(NO3)3 · 9H2O–Bi5O(OH)9(NO3)4 · 9H2O–glycine/urea with different metal nitrate/fuel molar ratios. The precursors’ thermal behavior is dependent on the fuel nature but practically independent to the fuel content. In glycine containing systems not all Bi2O3 is included into mixed oxides during the decomposition. Its presence was identified through the existence of two endothermic phase transitions (TDTA max at 745 and 818 °C) assigned to Bi2O3 α→δ transition, and its melting. The thermal investigations performed on oxides samples reveal for all oxides, independent on the precursor system, a similar behavior. For all the oxides was identified both the Curie temperature (which decreases with the annealing cycles) and the incongruent melting point (which is with ~10 °C higher for glycine generated oxides comparative with urea ones). The structural analysis shows in the case of the oxides prepared using urea as fuel, a faster evolution toward a single phase composition with the temperature, the formation of the BiFeO3 perovskite phase being completed in the temperature range of 500–550 °C. Only some traces of Bi36Fe2O57 were identified at the detection limit. TEM analysis performed on the BiFeO3 thermally treated at 500 °C for 3 h revealed the presence of small particles with an average size of ~33 nm and polycrystalline agglomerates with an average size of ~100 nm for glycine/urea derived oxides.

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Journal of Thermal Analysis and Calorimetry
Authors:
Mauro da Silva
,
Flávio de Souza Carvalho
,
Tereza da Silva Martins
,
Márcia de Abreu Fantini
, and
Paulo Isolani

more efficient device building [ 5 ] among other high technology applications [ 6 , 7 ] and academic investigations [ 8 , 9 ]. On this way, lanthanide oxides-based and doped nanoparticles represent an interesting investigation field. On

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Journal of Flow Chemistry
Authors:
Zine Eddine Hamami
,
Laurent Vanoye
,
Pascal Fongarland
,
Claude de Bellefon
, and
Alain Favre-Reguillon

. Greenberg , J. F. Liebman , J. S. Valentine , Eds.; Chapman & Hall: New York, 1995 . 2. Denisov , E. T. ; Afanas'ev , I. B. Oxidation and

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