[2B01-04] Waste Processing and Volume Reduction

10:05 AM - 10:20 AM JST(1:05 AM - 1:20 AM UTC)

[2B03] Volume reduction and recycling of ¹³⁷Cs-adsorbed transition metal ferrocyanide by partial chemical decomposition

*Tsuneki Ichikawa^1,2, Kazuo Yamada² (1. Hokkaido Univ., 2. NIES)

Keywords:

Radiocesium,Contaminated fly ash,Transition metal ferrocyanide,Coprecipitation,Alkaline decomposition,Volume reduction

Volume reduction of the F1 nuclear accident-generated radiocesium-contaminated wastes by pyrodecontamination results in the formation of ¹³⁷Cs-enriched fly ash. Further volume reduction can be attained by decontaminating the ash with water and then fixing the removed Cs in the water. Coprecipitation of Cs with transition metal ferrocyanide is a convenient way of removing Cs from the contaminated water. The removal is fast and necessitates no special facility, though the degree of the volume reduction is not so high. For increasing the degree of volume reduction, Cu was used in the present study as a transition metal and the resultant Cs-adsorbed copper ferrocyanide precipitate was partially decomposed with a NaOH solution into Cs-adsorbed copper ferrocyanide, Cu(OH)₂ and dissolved ferrocyanide ions, and Cu(OH)₂ in the precipitate was then removed with a HCl solution. The weight of the resultant Cs-adsorbed copper ferrocyanide was reduced to 1/5 of the initial one. The removed Cu and ferrocyanide ions can be reused for another coprecipitation process.