Sintering of monoclinic-SrAl2Si2O8 ceramics and their immobilization of Sr
3 December 2019
Revised: 28 March 2020
Accepted: 30 March 2020
Available online: 3 April 2020
Abstract: Monoclinic SrAl2Si2O8 ceramics for the immobilization of Sr were prepared by a liquid-phase sintering method. The sintering temperature, mineral phase composition, microstructure, flexural strength, bulk density, and Sr ions leaching characteristic of SrAl2Si2O8 ceramics were investigated. A crystalline monoclinic-SrAl2Si2O8 phase was formed by liquid phase sintering at 1223 K. The introduction of four different flux agents (B2O3, CaO·2B2O3, SrO·2B2O3 and BaO·2B2O3) to the SrAl2Si2O8 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. The product consistency tests showed that the leaching concentration of Sr ions in sample SAS-B with flux agents B2O3 was the lowest and the leaching concentration of Sr ions in sample SAS-B2B with flux agents BaO·2B2O3 was the highest. These results show that the leaching concentration of Sr ions depends largely on amorphous phase in the ceramics. Meanwhile, the formation of mineral analog ceramic containing Sr is an important factor to improve the immobilization of Sr.