燃煤过程中稀土元素分异机理研究

With increasing global demand for rare earth elements and yttrium (REY), coal ash as a potential REY source, due to their high REY concentrations, has received more attentions from the world. However, behaviors of REY during coal combustion, as well as modes of occurrences of REY in coal combustion products, are still unsolved, which limit it further industrial utilization and extraction. Thus, the applicants propose the submitted project named Differentiation Mechanism of REY during Coal Combustion. In the proposed study, a series typical samples of high-REY coals and their combustion products from power plants and laboratory simulation combustion, China, will be investigated by multi-disciplinary theories and methods, such as coal geology, coal combustion, geochemistry, and mineralogy. The study will focus on behaviors of REY releasing, interaction and reaction with mineral matter in the high-temperature region, their modes of occurrences evolutions in low-temperature region, and establish a dynamic model of REY conversion and migration during the combustion process. The study will provide scientific knowledge to the industrialization and extraction of REY in coal ash, and further provide theoretical supports for the recycling utilization of coal ash.

随着全球稀土需求的不断增大，将煤灰作为稀土来源的研究日益受到各国重视。然而燃煤过程中稀土的演化行为及其在煤灰中赋存特征方面研究的不足成为制约其工业化利用的关键因素。因此，申请者提出燃煤过程中稀土元素分异机理研究的项目申请。项目拟以我国典型的富稀土煤及电厂燃煤产物为研究对象，通过煤地质学、煤燃烧学、地球化学、矿物学等学科理论和先进的实验方法，采用现场和实验室研究相结合的方案，查明煤燃烧过程中稀土元素释放规律，揭示高温区稀土元素与矿物质相互作用及反应机理、低温区稀土元素和燃煤产物的形态演变规律，建立燃煤过程中稀土元素形态转换和迁移规律的动力学模型，阐明燃煤过程中稀土元素分异机理。项目成果将为煤灰中稀土利用和提取方法的选择提供科学依据，也为煤灰资源的绿色循环开发利用提供理论支持。

本项目以我国典型的富稀土煤及电厂燃煤产物为研究对象，通过煤地质学、煤燃烧学、地球化学、矿物学等学科理论和实验方法，查明了煤燃烧过程中稀土元素释放规律，揭示了稀土元素与矿物质相互作用、燃煤产物的形态演变对稀土赋存的影响。燃煤产物中稀土元素的分布和赋存状态受到入料原煤中稀土元素的赋存状态、燃烧工况等因素的影响。电厂燃煤产物中稀土含量明显高于入料煤中，且稀土元素的配分模式基本上继承于对应的入料煤。燃煤过程中与有机质和粘土矿物有关的稀土主要转化到非晶质玻璃体中，部分保存在莫来石等矿物中。煤灰中有单独产出细粒含稀土矿物，或者包裹在玻璃质中。项目成果将为煤灰中稀土利用和提取方法的选择提供科学依据。项目组成员在International Journal of Coal Geology、Chemical Geology、Organic Geochemistry、Minerals等重要国际学术刊物上发表SCI论文5篇，出版专著一部。