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Influence of ammonium sulfate leaching agent on engineering properties of weathered crust elution-deposited rare earth ore
https://orcid.org/http://orcid.org/0000-0001-5404-6694
Rare earth resources in the weathered crust elution-deposited rare earth ore (WCEDRE-ore) are mainly recovered by in situ leaching process. A new understanding of the engineering properties modification of WCEDRE-ore as well as the occurring microscopic mechanism was presented when leaching using ammonium sulfate agent occurred. The soil–water chemical reactions in leaching had a significant impact on engineering properties (such as permeability and strength) of WCEDRE-ore, which determined the success or failure of in situ leaching process. To reveal the internal processes and effects of ammonium sulfate leaching on WCEDRE-ore, indoor tests including leaching tests, chemical analyses, triaxial tests and nuclear magnetic resonance (NMR) tests were conducted. The results show that: (1) Under the action of ion exchange and seepage, the dispersion, deposition and clogging of fine particles occurred repeatedly and alternately along the seepage direction. (2) During the leaching process, the total porosity of the ore samples rarely changed, but the migration of fine particles leads to the transformation of micropores, mesopores and macropores in weathered-ore soil samples as well as the change of pore connectivity. As a result, the permeability coefficient of the tested soil samples decreased significantly at the beginning of test and then rose slightly. (3) Increased salt content during the leaching process enhanced soil cementation and structure until the end of ion exchange. However, owing to the loose pore structure in the upper part of sample and the dense pore structure in the lower part of the tested specimen generated by particle migration, the strength of soil sample was weakened, which was conducive to the occurrence of shear failure in the upper part of sample.
Influence of ammonium sulfate leaching agent on engineering properties of weathered crust elution-deposited rare earth ore
https://orcid.org/http://orcid.org/0000-0001-5404-6694
Rare earth resources in the weathered crust elution-deposited rare earth ore (WCEDRE-ore) are mainly recovered by in situ leaching process. A new understanding of the engineering properties modification of WCEDRE-ore as well as the occurring microscopic mechanism was presented when leaching using ammonium sulfate agent occurred. The soil–water chemical reactions in leaching had a significant impact on engineering properties (such as permeability and strength) of WCEDRE-ore, which determined the success or failure of in situ leaching process. To reveal the internal processes and effects of ammonium sulfate leaching on WCEDRE-ore, indoor tests including leaching tests, chemical analyses, triaxial tests and nuclear magnetic resonance (NMR) tests were conducted. The results show that: (1) Under the action of ion exchange and seepage, the dispersion, deposition and clogging of fine particles occurred repeatedly and alternately along the seepage direction. (2) During the leaching process, the total porosity of the ore samples rarely changed, but the migration of fine particles leads to the transformation of micropores, mesopores and macropores in weathered-ore soil samples as well as the change of pore connectivity. As a result, the permeability coefficient of the tested soil samples decreased significantly at the beginning of test and then rose slightly. (3) Increased salt content during the leaching process enhanced soil cementation and structure until the end of ion exchange. However, owing to the loose pore structure in the upper part of sample and the dense pore structure in the lower part of the tested specimen generated by particle migration, the strength of soil sample was weakened, which was conducive to the occurrence of shear failure in the upper part of sample.
Influence of ammonium sulfate leaching agent on engineering properties of weathered crust elution-deposited rare earth ore
https://orcid.org/http://orcid.org/0000-0001-5404-6694
Rare earth resources in the weathered crust elution-deposited rare earth ore (WCEDRE-ore) are mainly recovered by in situ leaching process. A new understanding of the engineering properties modification of WCEDRE-ore as well as the occurring microscopic mechanism was presented when leaching using ammonium sulfate agent occurred. The soil–water chemical reactions in leaching had a significant impact on engineering properties (such as permeability and strength) of WCEDRE-ore, which determined the success or failure of in situ leaching process. To reveal the internal processes and effects of ammonium sulfate leaching on WCEDRE-ore, indoor tests including leaching tests, chemical analyses, triaxial tests and nuclear magnetic resonance (NMR) tests were conducted. The results show that: (1) Under the action of ion exchange and seepage, the dispersion, deposition and clogging of fine particles occurred repeatedly and alternately along the seepage direction. (2) During the leaching process, the total porosity of the ore samples rarely changed, but the migration of fine particles leads to the transformation of micropores, mesopores and macropores in weathered-ore soil samples as well as the change of pore connectivity. As a result, the permeability coefficient of the tested soil samples decreased significantly at the beginning of test and then rose slightly. (3) Increased salt content during the leaching process enhanced soil cementation and structure until the end of ion exchange. However, owing to the loose pore structure in the upper part of sample and the dense pore structure in the lower part of the tested specimen generated by particle migration, the strength of soil sample was weakened, which was conducive to the occurrence of shear failure in the upper part of sample.
Influence of ammonium sulfate leaching agent on engineering properties of weathered crust elution-deposited rare earth ore
Acta Geotech.
Wang, Hao (author) / Wang, Xiaojun (author) / Wang, Yu (author) / Wang, Daihui (author) / Hu, Kaijian (author) / Zhong, Wen (author) / Guo, Zhongqun (author)
Acta Geotechnica ; 19 ; 2041-2062
2024-04-01
22 pages
Article (Journal)
Electronic Resource
English
Leaching process , Pore structure , Permeability , Particle migration , Shear strength , Weathered crust elution-deposited rare earth ore Engineering , Geoengineering, Foundations, Hydraulics , Solid Mechanics , Geotechnical Engineering & Applied Earth Sciences , Soil Science & Conservation , Soft and Granular Matter, Complex Fluids and Microfluidics
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