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Synthesis of microspheres of triuranium octaoxide by simultaneous water and nitrate extraction from ascorbate-uranyl sols.

Brykala M, Deptula A, Rogowski M, Lada W, Olczak T, Wawszczak D, Smolinski T, Wojtowicz P, Modolo G - J Radioanal Nucl Chem (2013)

Bottom Line: Drops of emulsion were firstly gelled by extraction of water by the solvent.Destruction of the microspheres during thermal treatment, owing to highly reactive components in the gels, requires modification of the gelation step by Double Extraction Process-simultaneously extraction of water and nitrates using Primene JMT, which completely eliminates these problem.Final step was calcination in air of obtained microspheres of gels to triuranium octaoxide.

View Article: PubMed Central - PubMed

Affiliation: Institute of Nuclear Chemistry and Technology (INCT), 16 Dorodna Str., 03-195 Warsaw, Poland.

ABSTRACT

A new method for synthesis of uranium oxide microspheres (diameter <100 μm) has been developed. It is a variant of our patented Complex Sol-Gel Process, which has been used to synthesize high-quality powders of a wide variety of complex oxides. Starting uranyl-nitrate-ascorbate sols were prepared by addition of ascorbic acid to uranyl nitrate hexahydrate solution and alkalizing by aqueous ammonium hydroxide and then emulsified in 2-ethylhexanol-1 containing 1v/o SPAN-80. Drops of emulsion were firstly gelled by extraction of water by the solvent. Destruction of the microspheres during thermal treatment, owing to highly reactive components in the gels, requires modification of the gelation step by Double Extraction Process-simultaneously extraction of water and nitrates using Primene JMT, which completely eliminates these problem. Final step was calcination in air of obtained microspheres of gels to triuranium octaoxide.

No MeSH data available.


SEM of triuranium octaoxide in shape of spherical particles obtained by: a IChTJ Process, b Double Extractions Process
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Fig5: SEM of triuranium octaoxide in shape of spherical particles obtained by: a IChTJ Process, b Double Extractions Process

Mentions: First weight loss of all obtained gels in temperatures 100–300 °C is connected to evaporation of molecular water and hydroxide groups, but also it is also connected to decomposition of the U-ASC-NO3–NH4OH gel, when one of component—ammonium nitrate—decomposes violently (see curve no. 1) [12]. The result is obtained of chipped spherical particles (Fig. 5a). The next weight loss with broad exothermic effect 350–550 °C, is connected with combustion of ASC and products of its decomposition. Only on curve no. 1 there is not observed exothermic effect of decomposition of organic compound. It is due to producing of high amount of energy in first exothermic effect what causes earlier decomposition of ascorbic acid.Fig. 5


Synthesis of microspheres of triuranium octaoxide by simultaneous water and nitrate extraction from ascorbate-uranyl sols.

Brykala M, Deptula A, Rogowski M, Lada W, Olczak T, Wawszczak D, Smolinski T, Wojtowicz P, Modolo G - J Radioanal Nucl Chem (2013)

SEM of triuranium octaoxide in shape of spherical particles obtained by: a IChTJ Process, b Double Extractions Process
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4514686&req=5

Fig5: SEM of triuranium octaoxide in shape of spherical particles obtained by: a IChTJ Process, b Double Extractions Process
Mentions: First weight loss of all obtained gels in temperatures 100–300 °C is connected to evaporation of molecular water and hydroxide groups, but also it is also connected to decomposition of the U-ASC-NO3–NH4OH gel, when one of component—ammonium nitrate—decomposes violently (see curve no. 1) [12]. The result is obtained of chipped spherical particles (Fig. 5a). The next weight loss with broad exothermic effect 350–550 °C, is connected with combustion of ASC and products of its decomposition. Only on curve no. 1 there is not observed exothermic effect of decomposition of organic compound. It is due to producing of high amount of energy in first exothermic effect what causes earlier decomposition of ascorbic acid.Fig. 5

Bottom Line: Drops of emulsion were firstly gelled by extraction of water by the solvent.Destruction of the microspheres during thermal treatment, owing to highly reactive components in the gels, requires modification of the gelation step by Double Extraction Process-simultaneously extraction of water and nitrates using Primene JMT, which completely eliminates these problem.Final step was calcination in air of obtained microspheres of gels to triuranium octaoxide.

View Article: PubMed Central - PubMed

Affiliation: Institute of Nuclear Chemistry and Technology (INCT), 16 Dorodna Str., 03-195 Warsaw, Poland.

ABSTRACT

A new method for synthesis of uranium oxide microspheres (diameter <100 μm) has been developed. It is a variant of our patented Complex Sol-Gel Process, which has been used to synthesize high-quality powders of a wide variety of complex oxides. Starting uranyl-nitrate-ascorbate sols were prepared by addition of ascorbic acid to uranyl nitrate hexahydrate solution and alkalizing by aqueous ammonium hydroxide and then emulsified in 2-ethylhexanol-1 containing 1v/o SPAN-80. Drops of emulsion were firstly gelled by extraction of water by the solvent. Destruction of the microspheres during thermal treatment, owing to highly reactive components in the gels, requires modification of the gelation step by Double Extraction Process-simultaneously extraction of water and nitrates using Primene JMT, which completely eliminates these problem. Final step was calcination in air of obtained microspheres of gels to triuranium octaoxide.

No MeSH data available.