Abstract
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.
Highlights
Weathered granite of ion-adsorption rare earth elements (REEs) ore collected at Jiangxi Province, China was investigated to identify the minerals abundant in REEs
Results of X-ray diffraction (XRD) measurements indicated that weathered granite, collected from an ion-adsorption ore in Dingnan County, Jiangxi Province, China, is mainly composed of quartz, K-feldspar, and kaolinite (Fig. 1)
The in-situ desorption experiments for the clay mineral particles showed that some REEs still remained in the clay minerals after the treatment with the ammonium sulfate solution
Summary
Weathered granite of ion-adsorption rare earth elements (REEs) ore collected at Jiangxi Province, China was investigated to identify the minerals abundant in REEs. Among the ores for REE production, ion-adsorption type ores existing mainly in Mesozoic granitic rocks of southern China are an important source of heavy REEs (HREEs: Gd–Lu), which are mostly more precious than light REEs (LREEs: La–Eu)[2]. This type of ore typically contains more than 50% REEs that can be extracted with ion-exchange treatments, such as ammonium sulfate [(NH4)2SO4] solution[3,4,5,6,7,8]. Granitic sites can be potential candidates for such disposals, and, among REEs, Eu-(III) has been used as an analog of trivalent actinides such as Am-(III) or Cm-(III)[26,27,28,29,30]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
