Abstract High concentration of Li, associated with coal, has been found in the Guanbanwusu coal Mine, Inner Mongolia, China. Earlier studies suggested that the lithium came from the Yinshan Paleoland during the peat-forming stage. The results of Li isotope determinations and calculations based on density functional theory (DFT) indicated that the lithium in the peat was released into the pore water and adsorbed by kaolinite edge surfaces (octahedral layers and/or tetrahedral layers) in the subsequent diagenesis and coalification. Alternatively, the Li of the partings, the floor, and the roof of the No. 6 coal seam also likely originated from the underlying bauxite of the Benxi Formation. Specifically, we determined the Li isotopic fractionations produced in chelation by small carboxylate (Δ7/6Liorganolithium-aq = −0.35‰), in adsorption onto kaolinite edge surfaces (Δ7/6Lioctahedral layer-aq = 4.36‰, Δ7/6Litetrahedral layer-aq = −4.53‰), and during incorporation into the lattices (Δ7/6LiAl2-aq = −8.2‰ and Δ7/6LiAl1-aq = −11.9‰). Combining these results with the δ7Li of 3.37 ± 0.13‰ for the moyite of the Yinshan Paleoland, we deduced a theoretical δ7Li range for the No. 6 coal seam and the partings, 2.85–7.38‰, exactly covering the determined δ7Li values of the coal and the partings. However, only the partings plotted in the theoretical δ7Li range of 1.13–5.66‰ assuming the bauxites (with δ7Li 1.30 ± 0.03‰) as the lithium source. During weathering and deposition, conversion of structurally incorporated Li within the grain boundaries of polycrystalline minerals of the bauxites to adsorbed Li was inferred to explain the Li isotope excursion in the latter case.

中文翻译：

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内蒙古官板乌苏矿6号煤层锂富集机理：基于锂同位素值和密度泛函理论计算的解释

摘要 内蒙古官半乌苏煤矿发现了与煤伴生的高浓度锂。早期的研究表明，锂来自泥炭形成阶段的银山古陆。基于密度泛函理论（DFT）的锂同位素测定和计算结果表明，泥炭中的锂被释放到孔隙水中，并在随后的成岩和煤化过程中被高岭石边缘表面（八面体层和/或四面体层）吸附. 或者，6号煤层的分缝、底板和顶板的里也很可能来源于本溪组下伏的铝土矿。具体来说，我们确定了小羧酸盐（Δ7/6Liorganolithium-aq = -0.35‰）螯合产生的Li同位素分馏，在吸附到高岭石边缘表面（Δ7/6Lioctahedral layer-aq = 4.36‰，Δ7/6Litetrahedral layer-aq = -4.53‰），以及在并入晶格期间（Δ7/6LiAl2-aq = -8.2‰和Δ7/6LiAl1- aq = -11.9‰）。将这些结果与银山古陆铁矿的 δ7Li 值 3.37±0.13‰ 相结合，我们推导出 6 号煤层和离隙的 δ7Li 理论值范围为 2.85-7.38‰，正好涵盖了确定的煤的 δ7Li 值和离别。然而，假设铝土矿（δ7Li 为 1.30 ± 0.03‰）作为锂源，则只有在 1.13–5.66‰ 的理论 δ7Li 范围内绘制的分离图。在风化和沉积过程中，推断铝土矿多晶矿物晶界内结构性结合的锂转化为吸附的锂，以解释后一种情况下的锂同位素偏移。