TY - JOUR
T1 - Solidification of uranium mill tailings by MBS-MICP and environmental implications
AU - Niu, Qianjin
AU - Li, Chunguang
AU - Liu, Zhenzhong
AU - Li, Yongmei
AU - Meng, Shuo
AU - He, Xinqi
AU - Liu, Xinfeng
AU - Wang, Wenji
AU - He, Meijiao
AU - Yang, Xiaolei
AU - Liu, Qi
AU - Liu, Longcheng
N1 - Publisher Copyright:
© 2022 Korean Nuclear Society
PY - 2022/10
Y1 - 2022/10
N2 - Uranium mill tailing ponds (UMTPs) are risk source of debris flow and a critical source of environmental U and Rn pollution. The technology of microbial induced calcium carbonate precipitation (MICP) has been extensively studied on reinforcement of UMTs, while little attention has been paid to the effects of MICP on U & Rn release, especially when incorporation of metakaolin and bacillus subtilis (MBS). In this study, the reinforcement and U & Rn immobilization role of MBS -MICP solidification in different grouting cycle for uranium mill tailings (UMTs) was comprehensively investigated. The results showed that under the action of about 166.7 g/L metakaolin and ∼50% bacillus subtilis, the solidification cycle of MICP was shortened by 50%, the solidified bodies became brittle, and the axial stress increased by up to 7.9%, and U immobilization rates and Rn exhalation rates decrease by 12.6% and 0.8%, respectively. Therefore, the incorporation of MBS can enhance the triaxial compressive strength and improve the immobilization capacity of U and Rn of the UMTs bodies solidified during MICP, due to the reduction of pore volume and surface area, the formation of more crystals general gypsum and gismondine, as well as the enhancing of coprecipitation and encapsulation capacity.
AB - Uranium mill tailing ponds (UMTPs) are risk source of debris flow and a critical source of environmental U and Rn pollution. The technology of microbial induced calcium carbonate precipitation (MICP) has been extensively studied on reinforcement of UMTs, while little attention has been paid to the effects of MICP on U & Rn release, especially when incorporation of metakaolin and bacillus subtilis (MBS). In this study, the reinforcement and U & Rn immobilization role of MBS -MICP solidification in different grouting cycle for uranium mill tailings (UMTs) was comprehensively investigated. The results showed that under the action of about 166.7 g/L metakaolin and ∼50% bacillus subtilis, the solidification cycle of MICP was shortened by 50%, the solidified bodies became brittle, and the axial stress increased by up to 7.9%, and U immobilization rates and Rn exhalation rates decrease by 12.6% and 0.8%, respectively. Therefore, the incorporation of MBS can enhance the triaxial compressive strength and improve the immobilization capacity of U and Rn of the UMTs bodies solidified during MICP, due to the reduction of pore volume and surface area, the formation of more crystals general gypsum and gismondine, as well as the enhancing of coprecipitation and encapsulation capacity.
KW - MBS-MICP grouting
KW - Solidification mechanism
KW - U and Rn immobilization
KW - Uranium mill tailings
UR - http://www.scopus.com/inward/record.url?scp=85130378276&partnerID=8YFLogxK
U2 - 10.1016/j.net.2022.04.022
DO - 10.1016/j.net.2022.04.022
M3 - Article
AN - SCOPUS:85130378276
SN - 1738-5733
VL - 54
SP - 3631
EP - 3640
JO - Nuclear Engineering and Technology
JF - Nuclear Engineering and Technology
IS - 10
ER -