Enrichment characteristics and genetic mechanisms of critical metals in coal from No.3 coal seam of Baoan Coal Mine in Ningwen Coalfield

With the increasing global demand for critical metals, particularly in fields such as renewable energy equipment, semiconductor devices, and defense industries, the supply-demand imbalance for lithium （Li）, cobalt （Co）, and rare earth elements （REY） has become more pronounced. Traditional metal deposits face challenges of resource depletion and environmental constraints, making it imperative to investigate the enrichment mechanisms of metals in non-conventional occurrences, which holds significant implications for energy transition and sustainable development. This paper focuses on the Baoan Coal Mine in the Ningwen Coalfield of Shandong Province, aiming to systematically evaluate enrichment characteristics and genetic mechanisms of critical metals within the coal-bearing strata. Advanced analytical techniques, including X-ray fluorescence spectroscopy （XRF） and inductively coupled plasma mass spectrometry （ICP-MS）, are employed to analyze the major and trace element compositions of coal and its roof/floor strata. Comparative assessments are conducted against global average values for coal-derived elements. The results reveal that the coal-bearing sequences are characterized by elevated concentrations of major elements such as SiO₂ and Al₂O₃, while trace elements Li and Co exhibit mild enrichment. Specifically, the Li content in the No. 3 upper coal seam averages 41.8 μg/g （peaking at 72.3 μg/g）, significantly exceeding global coal averages. The No. 3 lower coal seam shows notable Co enrichment, with a mean concentration of 11.8 μg/g. Additionally, the total REY content in the roof and floor strata averages 283 μg/g, suggesting potential for REY extraction from coal ash. Geochemical indicators, including Al₂O₃/TiO₂ ratios and REY partitioning patterns, indicate that terrigenous materials predominantly originate from felsic to intermediate magmatic rocks. The depositional environment, dominated by fluvial-deltaic systems with minimal marine influence, further constrains the enrichment processes. This study provides a comprehensive geochemical framework for understanding critical metal enrichment in coal-bearing strata, offering scientific support for resource evaluation and green industrial transformation in the western Shandong region. The findings also serve as a reference for exploring coal-hosted critical metal resources in analogous geological settings.