Development of Fluorination Decontamination Technique for Uranium Bearing Wastes

Author(s):  
Kenichi Fujiwara ◽  
Tomozou Sasaki ◽  
Yuzou Saita ◽  
A. Kamei ◽  
T. Fukui

A matrix of uranium bearing wastes (sludge, incineration ashes) bonds uranium tightly, and some wastes (narrow pipes, filters, etc.) have complicated shapes. This research was intended to achieve the assumed clearance level (0.3Bq/g) and to reduce the amount of secondary wastes. One of the uranium decontamination processes is the fluorination decontamination process in which CIF3 is used as a decontamination agent to fluorinate uranium bearing wastes to gaseous UF6 which can be recovered by cold or chemical trapping. The research test variables were decontamination temperature, decontamination temperature history and decontamination period. Filters and the main sludge could be decontaminated below the assumed clearance level when treated at 500 °C for 3 hours.

Chemosphere ◽  
2021 ◽  
pp. 132498
Author(s):  
Claude-Alla Joseph ◽  
Lotfi Khiari ◽  
Jacques Gallichand ◽  
Ned Beecher

2008 ◽  
Vol 57 (3) ◽  
pp. 411-417 ◽  
Author(s):  
M. Takaoka ◽  
T. Yamamoto ◽  
S. Fujiwara ◽  
K. Oshita ◽  
N. Takeda ◽  
...  

In this study, the chemical states of chromium (Cr), arsenic (As), and selenium (Se) in sewage sludge incineration ash were determined by X-ray absorption fine structure (XAFS) spectroscopy. Sewage sludge incineration ash was sampled from several facilities, and XAFS measurements were carried out with a beam line BL01B1 at the SPring-8 facility. Cr K-edge X-ray absorption near-edge structure (XANES) spectra suggested that Cr compounds were predominantly speciated as Cr(III) and the fraction of Cr(VI) was very minor. Compared to the reference materials, Cr XANES spectra of the incineration ashes were similar to those of FeCr2O4, Cr(OH)3, and CaCr2O4. As K-edge XANES spectra indicated that As(V) compounds were present in incineration ashes. Because the chemical state of As in sewage sludge was As3 +  in our previous study, we speculated that the chemical state of As changed into As(V) during the incineration process. According to Se K-edge XANES spectra, Se compounds were predominantly Se(IV), and a slight difference was observed in the chemical states amongst facilities using inorganic or organic coagulants in the dewatering process.


1992 ◽  
Vol 25 (4-5) ◽  
pp. 307-314 ◽  
Author(s):  
A. W. van der Vlies ◽  
J. H. B. te Marvelde

Recycling of sewage sludge will soon no longer be possible in The Netherlands, or will be possible only to a very limited degree. For that reason, part of the sewage sludge will have to be incinerated. This will happen particularly in those areas where tipping space is very limited. A sludge incineration plant is planned to be built in the town of Dordrecht, with a capacity of 45,000 tonnes dry solids per year. The plant will be subject to the very strict flue gas emission requirements of the Dutch Guideline on Incineration. The Guideline demands a sophisticated flue gas purification procedure.


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