地质学报2024，Vol.98Issue(8)：2452-2471,20.DOI:10.19762/j.cnki.dizhixuebao.2024219
云南普阳煤矿新近系褐煤中稀土元素的赋存状态
Modes of occurrence of rare earth elements in Neogene lignite from the Puyang mine,Yunnan
摘要
Abstract
Despite extensive research,the modes of occurrence of rare earth elements and yttrium (REY) in lignite remain poorly understood. Two key questions persist:① Do REY primarily associate with organic matter or mineral matter in lignite?② Lignite contains a large amount of oxygen-containing functional groups which are easily disturbed by acid leaching,does the high proportion of REY extracted by HCl during sequential chemical extraction originate from minerals as carbonates,phosphates,mono-sulfides,or from organic matter?The present study investigates the modes of occurrence of REY in Neogene lignite from the Puyang mine using a multi-faceted approach. We combined conventional sequential chemical extraction with float-sink separation and Fourier transform infrared spectroscopy (FTIR) analysis. Results show that the M2 and M3 coals are classified as very low-medium ash,medium-high volatile,and medium-sulfur coals. Mineral analysis revealed quartz,calcite,kaolinite,and pyrite as the dominant minerals. Major element oxides in the M2 and M3 coals are dominated by SiO2 and Al2O3. Based on Seredin-Dai's classification,the REY distribution patterns in these coals exhibit L-type and N-type characteristics,with a slight enrichment in the M2 coal. Sequential chemical extraction results revealed that HCl leached the majority of REY,followed by HNO3. Approximately 10％ of REY was leached by HF,with a small proportion remaining in the residue. Float-sink separation experiments demonstrated that REY preferentially concentrates in low-density components. FTIR analysis showed an increase in oxygen-containing functional groups,such as phenol hydroxyl and hydroxyl groups,in the analyzed samples after HCl leaching. This increase may be caused by the migration of REY,which bind to the phenol hydroxyl and hydroxyl sites during HCl treatment. Collectively,these findings indicate that REY in the M2 and M3 coals mainly occur in the organic matter,with a minor fraction associated with silicate minerals. Carbonate,phosphate,mono-sulfide,and bisulfide minerals may also host a certain portion of REY. The unusually high proportion of REY extracted by HCl during the sequential chemical extraction procedure mainly originates from the organic matter.关键词
普阳煤矿/褐煤/稀土元素/逐级化学提取/红外光谱Key words
Puyang mine/lignite/rare earth elements and yttrium/sequential chemical extraction/Fourier transform infrared spectroscopy (FTIR)引用本文复制引用
汪小妹,郭星星,韩宇轩,徐振宇,杨浩然,李宝庆..云南普阳煤矿新近系褐煤中稀土元素的赋存状态[J].地质学报,2024,98(8):2452-2471,20.基金项目
本研究受国家重点研发计划项目(2021YFC2902000)、国家自然科学基金项目(42372190、42172194、41972181)、新疆维吾尔自治区重大科技专项项目(项目编号:2022A03014-2),以及中国地质大学(武汉)学科杰出人才基金项目(102-162301192664)资助. （2021YFC2902000）
