四川盆地东部晚二叠世煤中稀土元素富集机理研究

The study on coal-hosted rare metal deposits has become a hot point issue of coal geology research. As the germanium, uranium and gallium have been extracted from coal successfully, rare earth elements and yittrium (REY) are supposed as the next metals to be extracted as a byproduct from coal, and are receiving more attention currently. This study choose the REY in the Late Permian coal in the eastern Sichuan basin as study object, based on the Inductively Coupled Plasma Mass Spectrometry (ICP-MS), X ray fluorescence (XRF), X ray diffraction (XRD), Scanning Electron Microscopy equipped with an Energy-Dispersed X-ray spectrometer (SEM-EDX), and Sequential Chemical Extraction (SCE) methods, combined with theories of coal geology, geochemistry and metallogeny, to deeply study the temporal and spatial distribution, origin and modes of occurrence of REY in the Late Permian coal in the eastern Sichuan basin. The forming period and geological-geochemical factors including source region, hydrothermal fluid, volcano activities and coal accumulation environment affected on the enrichment of REY in coal will be elucidated. Linked with the basin evolution, the enrichment mechanism of REY in coal will be proposed.

煤型稀有金属矿床的研究，是当今煤地质学研究的热点之一。现从煤中提取利用的有益金属有锗、铀和镓，而稀土作为煤中下一个最有可能被提取的元素，日益受到重视。本课题以四川盆地东部晚二叠世煤中异常富集的稀土元素为研究对象，利用电感耦合等离子体质谱（ICP-MS）、X射线荧光光谱（XRF）、X射线衍射（XRD）、带能谱的扫描电镜（SEM-EDX）和逐级化学提取（SCE）等方法，充分运用煤地质学、地球化学和矿床学等理论，深入研究四川盆地东部晚二叠世煤中稀土元素的时空分布、物质来源和赋存状态，阐明煤中稀土元素的形成期次和影响其形成的地质地球化学因素（物源、热液流体、火山活动和聚煤环境等），结合盆地演化历史揭示煤中稀土元素富集机理。

煤型稀有金属矿床是近年来煤地质学研究的前沿领域之一，吸引了国内外较多的关注。本项目综合运用煤地质学、矿物学、地球化学和冶金学等理论，对四川盆地东部晚二叠世含煤岩系（以中梁山煤田和渝东南煤田为例）中稀有金属（稀土元素）的分布规律、富集机理及可提取性进行来研究。研究发现中梁山和渝东南煤田煤的主要物质来源不是前人认为的康滇古陆，煤中稀有金属（稀土元素）主要是由于热液侵入影响形成的，凝灰岩中稀有金属（稀土元素）主要是源于喷发的基性火山灰，中梁山煤田K7煤层、K1煤层上分层和渝东南煤田K1煤层具有成为提取稀土元素的潜在原料的可能性。采用碱法烧结-水浸-酸浸能有效地实现凝灰岩中稀土元素、镓和铌的分离，稀土元素的总浸出率达85.81%，镓的总浸出率达93.37%，铌进一步富集于残渣之中。本次研究丰富了煤型稀有金属矿床实例，为下一步综合开发利用含煤岩系中稀有金属打下了基础。