Sewage sludge ash contaminated with radiocesium; Solidification with alkaline-reacted metakaolinite (geopolymer) and Portland cement

Kozai, Naofumi   ; Sato, Junya ; Osugi, Takeshi  ; Shimoyama, Iwao   ; Sekine, Yurina   ; Sakamoto, Fuminori  ; Onuki, Toshihiko

Radiocesium-bearing SSA was solidified in geopolymer (GP) and ordinary Portland cement (OPC) and the characteristics of the solidified bodies were investigated by various aspects including mechanical strength, transformation of SSA components during solidification, and radiocesium confinement ability by leaching test. After static leaching test at C, Cs was hardly leached out from the GP-solidified bodies containing SSA at 30 wt% to ultrapure water ( 0.1%), whereas more than 30% Cs was leached from the OPC-solidified bodies containing SSA at 30 wt%. GP is far superior to OPC for solidifying radiocesium-bearing SSA.