The types, contents, and microstructures of clay minerals play important roles in controlling the adsorption and desorption of ion-absorbed type rare earth ores and heavy metals. By selecting a typical rare earth ore profile, we conducted a leaching experiment and used XRD (X-ray diffraction) and TEM (Transmission electron microscopy) analyses to determine the clay mineral types and microstructural changes after various leaching periods. The XRD phase analyses showed that the main minerals in the simulated rare earth ore were quartz, potassium feldspar, kaolinite, and illite. TEM images showed that the mineral aggregates were broken, disintegrated, and transformed by the leaching process, and a large number of moire fringes were visible. With continuous leaching, REEs (Rare Earth Elements) were gradually re-solved and leached. The results of the leaching experiment indicate that fine-grained minerals in rare earth ores, such as potassium feldspar and clay minerals, migrated downward with the leaching solution. Leaching also promoted the alteration of potassium feldspar to clay minerals, as well as mutual alteration of clay minerals. Under acidic or neutral conditions during the early stage, potassium feldspar was altered to kaolinite or illite, whereas during the middle and late stages of leaching it was altered as follows: illite → mixed-layer illite–kaolinite → kaolinite → mixed-layer kaolinite–illite → illite. This transformation has an important effect on the release of REEs and heavy metals and provides insights into improving the leaching process and explaining heavy metal pollution in rare earth mining areas.

粘土矿物的种类、含量和微观结构在控制离子吸附型稀土矿和重金属的吸附和解吸过程中起着重要作用。通过选择典型的稀土矿石剖面，我们进行了浸出实验，并使用 XRD（X 射线衍射）和 TEM（透射电子显微镜）分析来确定不同浸出期后粘土矿物的类型和微观结构变化。XRD物相分析表明，模拟稀土矿的主要矿物为石英、钾长石、高岭石和伊利石。透射电镜图像显示，矿体在浸出过程中破碎、崩解、转化，可见大量莫尔条纹。随着连续浸出，REE（稀土元素）逐渐被重新溶解和浸出。浸出实验结果表明，稀土矿中钾长石、粘土矿物等细粒矿物随浸出液向下迁移。浸出也促进了钾长石向粘土矿物的蚀变，以及粘土矿物的相互蚀变。早期在酸性或中性条件下钾长石转变为高岭石或伊利石，浸出中后期转变为：伊利石→伊利石混合层-高岭石→高岭石→混合层高岭石-伊利石→伊利石。这种转变对 REE 和重金属的释放具有重要影响，并为改进浸出过程和解释稀土矿区的重金属污染提供了见解。