Partial rehydration of tubular halloysite (7 Å) immersed in La(NO3)3 solution for 3 years and its implication for understanding REE occurrence in weathered crust elution-deposited rare earth ores

Zhou，Junming1,2; Li，Mengyuan1,2; Yuan，Peng1; Li，Yun3; Liu，Hongmei1; Fan，Wenxiao1,2; Liu，Dong1; Zhang，Huan1,2

2021-11-01

10.1016/j.clay.2021.106244

APPLIED CLAY SCIENCE   影响因子和分区

0169-1317

Clay minerals are the main carriers of rare earth elements (REE) in weathered crust elution-deposited rare earth (WED-RE) ores. The clay mineral-water interface reaction is among the most important interactions controlling the aggregation and transportation of REE(III) ions. Yet long-term experiments of interactions between REE(III) ions and clay minerals are scarce in the literature. Here, two typical clay minerals that commonly occur in WED-RE ores, namely tubular halloysite (7 Å) and platy kaolinite, were immersed in a La solution for 3 consecutive years. The specimens' characteristics were systematically determined using X-ray diffraction (XRD), transmission electron microscope (TEM), infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS). The partial rehydration of tubular halloysite (7 Å) was observed, with the resulting rehydrated halloysite characterized by lattice fringes having d-values of ~1.000 and 0.830 nm, whose distribution features demonstrated that the partial rehydration happened initially at the outermost layers of the halloysite (7 Å). By contrast, both the morphology and structure of kaolinite remained intact after its 3-year-long immersion in the La solution. For both immersed halloysite and kaolinite, the La existed as inner-sphere complexes, outer-sphere complexes, and hydroxide particles adsorbed on the surface of minerals. However, La(III) ions partially penetrated the interlayer of halloysite but did not enter that of kaolinite. Accordingly, the intercalation of La(III) in halloysite may facilitate the rehydration of halloysite (7 Å). These experimental results provide novel insight into the conditions for rehydrating tubular halloysite (7 Å), and indicate a new possible state of REE(III) in WED-RE ores, both of which help us to better understand the geochemical behavior of REE and clay minerals in WED-RE ores.

Halloysite Kaolinite La(III) ions Rehydration Weathered crust elution-deposited rare earth ores

SCI ; EI

英语

其他

WOS:000705551800009

20213310786447

Infrared spectroscopy ; Ions ; Kaolinite ; Lanthanum compounds ; Ores ; Transmission electron microscopy ; X ray photoelectron spectroscopy

Minerals:482.2 ; Inorganic Compounds:804.2

GEOSCIENCES

2-s2.0-85112485337

Scopus

1.CAS Key Laboratory of Mineralogy and Metallogeny,Guangdong Provincial Key Laboratory of Mineral Physics and Materials,Guangzhou Institute of Geochemistry,CAS Center for Excellence in Deep Earth Science,Chinese Academy of Sciences,Guangzhou,510640,China
2.University of Chinese Academy of Sciences,Beijing,100049,China
3.Academy for Advanced Interdisciplinary Studies,Southern University of Science and Technology,Shenzhen,518055,China

Zhou，Junming,Li，Mengyuan,Yuan，Peng,et al. Partial rehydration of tubular halloysite (7 Å) immersed in La(NO3)3 solution for 3 years and its implication for understanding REE occurrence in weathered crust elution-deposited rare earth ores[J]. APPLIED CLAY SCIENCE,2021,213.

Zhou，Junming.,Li，Mengyuan.,Yuan，Peng.,Li，Yun.,Liu，Hongmei.,...&Zhang，Huan.(2021).Partial rehydration of tubular halloysite (7 Å) immersed in La(NO3)3 solution for 3 years and its implication for understanding REE occurrence in weathered crust elution-deposited rare earth ores.APPLIED CLAY SCIENCE,213.

Zhou，Junming,et al."Partial rehydration of tubular halloysite (7 Å) immersed in La(NO3)3 solution for 3 years and its implication for understanding REE occurrence in weathered crust elution-deposited rare earth ores".APPLIED CLAY SCIENCE 213(2021).