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<p>The Niobium–Yttrium–Fluorine (NYF) pegmatites exhibit mineralization (i.e., columbite, xenotime, and fluorite) accompanied by elevated radioactivity from thorite, monazite, and zircon. Zircon contains up to 5.48 wt% HREE₂O₃, featuring Y and Th substitution for Zr. Ferro-columbite is distinguished by the predominance of Fe<sub>2</sub>O<sub>3</sub> over MnO, with averages Fe<sub>2</sub>O<sub>3</sub>/MnO ratio of 22.5 compared to 0.97 wt%. REE mineralization is comprised of fluorocarbonates/fluorides (synchysite, bastnäsite, fluorite) and phosphates (monazite, xenotime). Xenotime is HREE-enriched (21.2 wt% Gd<sub>2</sub>O<sub>3</sub>-Lu<sub>2</sub>O<sub>3</sub>), while Ce-dominated LREE occur in synchysite (23.94 wt%), bastnäsite (39.35 wt%), and monazite (32.83 wt%). Radiological analyses reveal elevated levels of (<sup>238</sup>U: 158 Bq·kg<sup>−1</sup>), (<sup>232</sup>Th: 196 Bq·kg<sup>−1</sup>), and (<sup>40</sup>K: 1521 Bq·kg<sup>−1</sup>), which exceed worldwide averages. The range of absorbed dose rates (D<sub>air</sub>) is from 150 to 743 nGy·h<sup>−1</sup>, with an average radium equivalent (Ra<sub>eq</sub>) of 555 Bq·kg<sup>−1</sup> (326–1680). The elevated levels of these radionuclides, indicative of significant radioactive concerns, underscore the imperative for comprehensive mineralogical and environmental characterization to mitigate ecological and health risks.</p>

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Radioactive, environmental investigation and mineral chemistry aspects of Niobium–Yttrium–Fluorine (NYF) Pegmatites bearing rare metals mineralization

  • 期刊论文

  • 发表日期：

    2025年7月15日

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  • Ahmed E. Abdel Gawad,
  • Elena G. Panova,
  • Mohamed M. Ghoneim,
  • Turki Kh. Faraj,
  • Mohamed Y. Hanfi

摘要

The Niobium–Yttrium–Fluorine (NYF) pegmatites exhibit mineralization (i.e., columbite, xenotime, and fluorite) accompanied by elevated radioactivity from thorite, monazite, and zircon. Zircon contains up to 5.48 wt% HREE₂O₃, featuring Y and Th substitution for Zr. Ferro-columbite is distinguished by the predominance of Fe2O3 over MnO, with averages Fe2O3/MnO ratio of 22.5 compared to 0.97 wt%. REE mineralization is comprised of fluorocarbonates/fluorides (synchysite, bastnäsite, fluorite) and phosphates (monazite, xenotime). Xenotime is HREE-enriched (21.2 wt% Gd2O3-Lu2O3), while Ce-dominated LREE occur in synchysite (23.94 wt%), bastnäsite (39.35 wt%), and monazite (32.83 wt%). Radiological analyses reveal elevated levels of (238U: 158 Bq·kg−1), (232Th: 196 Bq·kg−1), and (40K: 1521 Bq·kg−1), which exceed worldwide averages. The range of absorbed dose rates (Dair) is from 150 to 743 nGy·h−1, with an average radium equivalent (Raeq) of 555 Bq·kg−1 (326–1680). The elevated levels of these radionuclides, indicative of significant radioactive concerns, underscore the imperative for comprehensive mineralogical and environmental characterization to mitigate ecological and health risks.