To alleviate the storage of red mud (RM) and the resulting pollution, this study presented an encapsulation-based strategy for the safe management of RM, and adopted ultra-high performance concrete (UHPC) as an encapsulating material due to its superior impermeability and chemisorption properties. It is noteworthy to find that encapsulated material suffered from a selective chemisorption and density functional theory (DFT) calculations were innovatively employed to investigate the selective chemisorption mechanism. The simulation results suggested that distinct bonding forms lead to the selective chemisorption of heavy metals, with Pb being adsorbed by Si–O–Pb chemical bonds and a strong Si–O–Pb–O–Si long chain, while As and Cr only form relatively weak As–O and Cr–O bonds through their attraction to O atoms. With the thickness of the encapsulating material increases, the synergistic effect of chemical solidification and physical package is provided to achieve a stronger stabilization effect. The leaching results indicated that the encapsulated RM exhibited exceptionally low concentrations of hazardous components (i.e., Na at 1.580 mg/L, As at 0.003 mg/L, Cr at 0.027 mg/L, and undetected levels of Pb in encapsulated RM with a thickness of 1.5 mm), far below the limits set by the United States Environmental Protection Agency (EPA). This study opening a new window for the sustainable and efficient management of hazardous solid waste.

为了减轻赤泥（RM）的储存和由此产生的污染，本研究提出了一种基于封装的赤泥安全管理策略，并采用超高性能混凝土（UHPC）作为封装材料，因为它具有优异的抗渗性和抗渗性。化学吸附特性。值得注意的是，封装材料遭受选择性化学吸附，并且创新性地采用密度泛函理论（DFT）计算来研究选择性化学吸附机制。模拟结果表明，不同的键合形式导致重金属的选择性化学吸附，其中Pb被Si– O –Pb化学键吸附，并且具有强的Si– O –Pb– O–Si长链，而As和Cr仅通过对O原子的吸引力形成相对较弱的As-O和Cr-O键。随着封装材料厚度的增加，提供化学固化和物理封装的协同作用，以达到更强的稳定效果。浸出结果表明，封装的 RM 中有害成分的浓度极低（即，Na 为 1.580 mg/L、As 为 0.003 mg/L、Cr 为 0.027 mg/L，而封装 RM 中未检测到的 Pb 浓度为1.5毫米），远低于美国环境保护署（EPA）设定的限值。该研究为危险固体废物的可持续、高效管理打开了新的窗口。