In order to investigate the influence of the ion exchange process on the permeability of rare earth ore bodies in the leaching process, a laboratory-scale comparative experiment with ammonium sulfate solution and deionized (DI) water as leaching solutions is conducted. Compared with the DI water leaching test, the permeability coefficient of the rare earth ore sample leached by the ammonium sulfate solution gradually decreases at the beginning and then increases with the completion of leaching. The physical and morphological evolutions of rare earth ore samples in this comparative experiment are also monitored by nuclear magnetic resonance and scanning electron microscopy. It is concluded that the change in the permeability coefficient arises from the adsorption–desorption of a large number of clay microparticles, resulting in a dynamic evolution of pore structures. Further mechanism analysis suggests that the change in internal ionic strength caused by ion exchange and leaching solution seepage promotes the adsorption–desorption behavior of clay microparticles.

中文翻译：

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实验室浸出试验中稀土的渗透性和吸附-解吸行为

为了研究浸出过程中离子交换过程对稀土矿体渗透性的影响，以硫酸铵溶液和去离子水为浸出溶液进行了实验室规模的对比实验。与去离子水浸出试验相比，硫酸铵溶液浸出的稀土矿石样品的渗透系数在开始时逐渐降低，然后随着浸出的完成而增加。还通过核磁共振和扫描电子显微镜监测了该对比实验中稀土矿石样品的物理和形态演变。结论是，渗透系数的变化是由大量粘土微粒的吸附-解吸引起的，导致孔隙结构的动态演变。进一步的机理分析表明，由离子交换和浸出液渗漏引起的内部离子强度的变化促进了粘土微粒的吸附-解吸行为。