<報文>ゼオライトによる高レベル放射性廃液からのCs, Srの除去ならびに沈殿物の固化

概要

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Ceramic solidification of Cs, Sr and denitrated precipitate has been studied by use of zeolites as an adsorbent and a solidification material. The adsorption ratio of Cs from the denitrated waste solution decreased in the order : chabazite (C)⪎ synthetic mordenite (SM) > natural mordenite ⪎ clinoptilolite > A, and that of Sr decreased as : A>>X>SM>Y>C. The mixing of different zeolites accelerated the reaction rate, and the adsorption of Sr attained equilibrium within 30 min in the mixed zeolites (A/SM=3〜1). The mixtures of zeolite A and the denitrated precipitates formed at pH6.3〜7.6 were calcined at temperatures up to 1,200℃ for 1hr. The phases of NaLa(MoO_4)_2,La_2Mo_2O_9,ZrO_2,SrRuO_3,NaAlSiO_4 (carnegieite and nepheline) and CsAlSi_2O_6 were observed in the ceramic products. The hauyne (Na_6Sr_2Al_6Si_6O_<24>(MoO_4)_2) phase was formed by the reaction of NaAlSiO_4 and precipitates (Sr^<2+> and MoO_4^<2->) above 900℃. The leaching rates of Cs and Sr were less than 10^<-8>g/cm^2・day for the calcined products containing about 10% precipitate. The solidification with calcined zeolites may enable simplification of the partitioning process.
東北大学の論文
1984-09-25