Sintering of monoclinic SrAl2Si2O8 ceramics and their Sr immobilization

Monoclinic SrAl 2 Si 2 O 8 ceramics for Sr immobilization were prepared by a liquid-phase sintering method. The sintering temperature, mineral phase composition, microstructure, flexural strength, bulk density, and Sr ion leaching characteristics of the SrAl 2 Si 2 O 8 ceramics were investigated. A crystalline monoclinic SrAl 2 Si 2 O 8 phase formed through liquid-phase sintering at 1223 K. The introduction of four flux agents (B 2 O 3 , CaO·2B 2 O 3 , SrO·2B 2 O 3 , and BaO·2B 2 O 3 ) to the SrAl 2 Si 2 O 8 ceramics not only reduced the densification temperature and decreased the volatilization of Sr during high-temperature sintering but also impacted the mechanical properties of the ceramics. Product consistency tests showed that the leaching concentration of Sr ions in the sample with flux agent B 2 O 3 was the lowest, whereas that of Sr ions in the sample with flux agent BaO·2B 2 O 3 was the highest. These results show that the leaching concentration of Sr ions depends largely on the amorphous phase in the ceramics. Meanwhile, the formation of mineral analog ceramics containing Sr is an important factor to improve Sr immobilization.