Tamusu mudstone formation, located in the Alxa area in western Inner Mongolia, is considered a potential host formation for high-level radioactive waste(HLW) underground disposal in China. In this study, complementary...Tamusu mudstone formation, located in the Alxa area in western Inner Mongolia, is considered a potential host formation for high-level radioactive waste(HLW) underground disposal in China. In this study, complementary analyses with X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), mercury intrusion porosimetry(MIP), and N_(2) physisorption isotherm were conducted on the Tamusu mudstone to characterize its physical characteristics and microstructural features, such as mineral compositions and pore structure. Several minerals, including carbonates, feldspar, clays and analcime, were identified in Tamusu mudstone by XRD. Images from FE-SEM show that pores in the Tamusu mudstone were dominantly on nanometer scale and generally located within their mineral matrix or at the interface with non-porous minerals. The combination of the MIP and N_2 physisorption curves indicated that the Tamusu mudstone has diverse pore sizes, a porosity varying from 2.34% to 2.84%, and a total pore volume in the range of 0.0065—0.0222 cm^(3)/g with the average pore diameter ranging from 9.6 nm to 19.23 nm. The specific surface area measured by MIP(2.572—5.861 m^(2)/g) was generally higher than that by N_(2) physisorption(1.29—3.04 m^(2)/g), due to the pore network effect, pore shape(e.g. ink-bottle shape), or technique limits. The results related to pore information can be applied as an input in the future to model single-or multi-phase fluid flow and the transport of radionuclides in porous geomedium by migration and diffusion.展开更多
基金financial support of the National Natural Science Foundation of China (Grant Nos.51979266,51879258 and 51991392)。
文摘Tamusu mudstone formation, located in the Alxa area in western Inner Mongolia, is considered a potential host formation for high-level radioactive waste(HLW) underground disposal in China. In this study, complementary analyses with X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), mercury intrusion porosimetry(MIP), and N_(2) physisorption isotherm were conducted on the Tamusu mudstone to characterize its physical characteristics and microstructural features, such as mineral compositions and pore structure. Several minerals, including carbonates, feldspar, clays and analcime, were identified in Tamusu mudstone by XRD. Images from FE-SEM show that pores in the Tamusu mudstone were dominantly on nanometer scale and generally located within their mineral matrix or at the interface with non-porous minerals. The combination of the MIP and N_2 physisorption curves indicated that the Tamusu mudstone has diverse pore sizes, a porosity varying from 2.34% to 2.84%, and a total pore volume in the range of 0.0065—0.0222 cm^(3)/g with the average pore diameter ranging from 9.6 nm to 19.23 nm. The specific surface area measured by MIP(2.572—5.861 m^(2)/g) was generally higher than that by N_(2) physisorption(1.29—3.04 m^(2)/g), due to the pore network effect, pore shape(e.g. ink-bottle shape), or technique limits. The results related to pore information can be applied as an input in the future to model single-or multi-phase fluid flow and the transport of radionuclides in porous geomedium by migration and diffusion.
