Abstract The objective of this study was to evaluate rare earth elements and yttrium (REY) concentrations in Pennsylvanian coal-bearing strata in the eastern part of the Illinois Basin (Indiana), specifically targeting coals and marine shales associated with the coals. Samples were collected from several coal mines and three boreholes. In total, 105 samples were analyzed using inductively coupled plasma - optical emission spectrometry (ICP-OES), including 69 coals, 31 shales, and 5 paleosols. Concentrations of REY in the coals vary from less than 200 ppm to more than 3000 ppm (on ash basis). Indirect evidence, including REY versus ash relationships, REY distribution patterns, and REY content in raw coal compared to that in washed coal, suggests that the organic association may be an important mode of REY occurrence in these coals. The Lower Block and the Upper Block Coal Members of the Brazil Formation and some coals of the Staunton Formation have the highest REY concentrations among those studied. Concentrations of REY in marine shales range from less than 200 to 800 ppm on ash basis. The majority of shale samples studied vary little from the REY values of the continental crust, but some show enrichments. Our results suggest that, while post-combustion coal ash of the high-REY coals are a potential source of these elements, significant efforts and resources are needed to make the studied shales a viable REY resource.

中文翻译：

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伊利诺伊盆地东部宾夕法尼亚煤和页岩中的稀土元素和钇

摘要 本研究的目的是评估伊利诺伊州盆地（印第安纳州）东部宾夕法尼亚煤层中的稀土元素和钇 (REY) 浓度，特别是针对煤和与煤相关的海相页岩。样品是从几个煤矿和三个钻孔中收集的。总共使用电感耦合等离子体-光学发射光谱法 (ICP-OES) 分析了 105 个样品，包括 69 个煤、31 个页岩和 5 个古土壤。煤中 REY 的浓度从小于 200 ppm 到大于 3000 ppm（以灰分计）不等。间接证据，包括 REY 与灰分的关系、REY 分布模式以及与洗煤中相比原煤中 REY 含量，表明有机结合可能是这些煤中 REY 发生的重要模式。巴西组的下块和上块煤层以及 Staunton 组的一些煤在所研究的那些煤中具有最高的 REY 浓度。海相页岩中 REY 的浓度范围为低于 200 至 800 ppm（以灰分计）。研究的大多数页岩样品与大陆地壳的 REY 值变化不大，但有些显示富集。我们的结果表明，虽然高 REY 煤的燃烧后煤灰是这些元素的潜在来源，但需要付出巨大的努力和资源才能使研究的页岩成为可行的 REY 资源。研究的大多数页岩样品与大陆地壳的 REY 值变化不大，但有些显示富集。我们的结果表明，虽然高 REY 煤的燃烧后煤灰是这些元素的潜在来源，但需要付出巨大的努力和资源才能使研究的页岩成为可行的 REY 资源。研究的大多数页岩样品与大陆地壳的 REY 值变化不大，但有些显示富集。我们的结果表明，虽然高 REY 煤的燃烧后煤灰是这些元素的潜在来源，但需要付出巨大的努力和资源才能使研究的页岩成为可行的 REY 资源。