This work is a first-order study to assess the suitability of an organic acid lixiviant to extract rare earth elements (REE) from coal preparation fines refuse sourced from a Pennsylvania mine with a total REE of ~ 300 ppm. The extraction of REE using an organic acid, in this case 0.1 M citric acid and 0.5 M trisodium citrate solution, is compared against 0.5 M (NH₄)₂SO₄, 1 M HCl, 1.2 M H₂SO₄, and 0.5 M ethylenediaminetetraacetic acid (EDTA). Ashing the coal waste material prior to leaching tests with the citrate solution nominally improved REE extraction. Buffered citrate solution recovered 7% of the total REE in the as-received Isabella Fines as compared to 11% in ashed samples, whereas (NH₄)₂SO₄ extracted 5–6%, respectively. EDTA recovered up to 33% of the total REE, most likely due to the higher coordination chelate bond. Mineral acids, however, outperformed the organic acids on ashed material (16–52% REE recovery), suggesting that organic acids may not be a suitable competitive option for REE extraction from these types of feedstocks.

这项工作是一项一级研究，旨在评估有机酸浸出剂是否适用于从来自宾夕法尼亚州矿山的煤制备细粉中提取稀土元素 (REE)，总 REE 约为 300 ppm。使用有机酸（在本例中为 0.1 M 柠檬酸和 0.5 M 柠檬酸三钠溶液）提取 REE 与 0.5 M (NH ₄ ) ₂ SO ₄、1 M HCl、1.2 MH ₂ SO ₄和 0.5 M 乙二胺四乙酸进行比较酸 (EDTA)。在浸出试验之前用柠檬酸盐溶液对煤废料进行灰化，名义上改善了稀土元素的提取。与灰化样品中的 11% 相比，缓冲柠檬酸盐溶液回收了原样伊莎贝拉细粒中总 REE 的 7%，而 (NH ₄) ₂ SO ₄分别提取了 5–6%。EDTA 回收了高达总 REE 的 33%，很可能是由于较高的配位螯合键。然而，矿物酸在灰分材料上的表现优于有机酸（16-52% REE 回收率），这表明有机酸可能不是从这些类型的原料中提取 REE 的合适竞争选择。