Nature of parent rocks, mineralization styles and ore genesis of regolith-hosted REE deposits in South China: An integrated genetic model

Li, Martin Yan Hei; Zhao, Wenqian; Zhou, Mei‐Fu

doi:10.1016/j.jseaes.2017.08.004

Cited by 182 publications

(87 citation statements)

References 203 publications

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“…These elements, along with some of the other rare earth elements (REEs), are considered critical to society because of their ubiquitous use in modern technologies and renewable energy solutions, and because limits on supply would hinder global economic and technological development [3][4][5] . Regolith-hosted IADs, also referred to as ion-adsorption clays, weathering crust elution-or laterite-hosted rare earth deposits [6][7][8][9] , readily liberate the metals following mild acidification during addition of ammonium sulfate leach solutions 10 . In such deposits, the REEs are inferred to be weakly adsorbed onto clay minerals (dominantly kaolinite and halloysite), as well as oxides, at a range of structural sites, including broken edge sites, charged aluminol or siloxane groups at defects and isomorphic substitutions (e.g.…”

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confidence: 99%

Adsorption of rare earth elements in regolith-hosted clay deposits

et al. 2020

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Global resources of heavy Rare Earth Elements (REE) are dominantly sourced from Chinese regolith-hosted ion-adsorption deposits in which the REE are inferred to be weakly adsorbed onto clay minerals. Similar deposits elsewhere might provide alternative supply for these high-tech metals, but the adsorption mechanisms remain unclear and the adsorbed state of REE to clays has never been demonstrated in situ. This study compares the mineralogy and speciation of REE in economic weathering profiles from China to prospective regoliths developed on peralkaline rocks from Madagascar. We use synchrotron X-ray absorption spectroscopy to study the distribution and local bonding environment of Y and Nd, as proxies for heavy and light REE, in the deposits. Our results show that REE are truly adsorbed as easily leachable 8-to 9-coordinated outer-sphere hydrated complexes, dominantly onto kaolinite. Hence, at the atomic level, the Malagasy clays are genuine mineralogical analogues to those currently exploited in China.

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confidence: 99%

Adsorption of rare earth elements in regolith-hosted clay deposits

et al. 2020

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“…Owing to these advantages, this deposit type is minable. However, the concentration of REEs in the ores is relatively low (< 2000 ppm) 4 , 8 , 10 , compared to the other types of REE ores, such as carbonatite (approx. 0.5–10 wt%) and alkaline rock types (approx.…”

Section: Introductionmentioning

confidence: 94%

“…In the upper layer, the content of clay (kaolinite and halloysite) increases due to the weathering of feldspar 3 , 4 , 14 , 15 . It has been reported that REEs are concentrated in the second and third layers (B and C) 4 , 10 . The weathering of the parent granite involves the alteration of REE-bearing primary minerals, such as allanite, titanite, fluorocarbonates (synchysite, parasite, and bastnaesite), gadolinite, hingganite, and yttrialite 3 , 8 , 10 , 16 .…”

Section: Introductionmentioning

confidence: 99%

Microscopic analyses of weathered granite in ion-adsorption rare earth deposit of Jianxi Province, China

Mukai

Kon

Sanematsu

et al. 2020

Sci Rep

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Weathered granite of ion-adsorption rare earth elements (REEs) ore collected at Jiangxi Province, China was investigated to identify the minerals abundant in REEs. The analyses of scanning electron microscopy (SEM)-energy dispersive spectrometry (EDS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for individual mineral particles of the weathered granite showed that kaolinitic particles formed by K-feldspar weathering contained large amounts of REEs. Scanning transmission electron microscopy (STEM)-EDS analyses revealed that the kaolinitic particles were mainly composed of kaolinite, illite and hematite. The elemental maps by Nano-SIMS for the kaolinitic particle clarified that La and Y are particularly concentrated in illite. The presence of illite presumably contributes to the formation of the REE accumulation zone in weathered granite. Furthermore, in the in-situ desorption experiment, nearly half the REEs (45.5%) remained in the kaolinitic particle after the treatment with 0.5 M ammonium sulfate solution. The desorption ratio of heavy REEs (HREEs: Gd–Lu) (60.4%) was lower than that of light REEs (LREEs: La–Eu) apart from Ce (69.0%). These results suggest that REEs form inner-sphere complexes on the kaolinitic particle. It can be assumed that the inner-sphere complexation suppresses the extraction ratio of REEs from the ores by ion-exchange treatment.

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“…However, the highest concentrations of LREE (up to 332 mg kg −1 of Ce, 169 mg kg −1 of La, 114 mg kg −1 of Nd and 332 mg kg −1 of Sm) were measured in soils developed on tonalitic rocks from an intrusive stock emplaced in the OMZ, the so-called Santa Olalla Igneous Complex (Romeo et al, 2006) in Huelva province. The LREE-enriched granitoids are often abundant in apatite, monazite, titanite and allanite formed by magma differentiation (Li et al, 2017). Interestingly, the largest abundances of Eu (13.6 mg kg −1 ) and Y (103 mg kg −1 ) occurred in soils on carbonate rocks of the external zone of the Betic Cordillera.…”

Section: Rare Earth Elements and Ytrium (Rey)mentioning

confidence: 99%