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[Display omitted] • The desorption mechanism was verified at the microscopic level. • Mg2+/Al3+ exchange with Y3+ on Si O Y to form Si O Mg/Al. • Al3+ has a stronger Y3+ desorption capability than Mg2+. • The desorption materials were from actual ion-adsorption type rare earths ore. Ion-adsorption type rare earths ore (IREO) is an important strategic resource that can be leached in-situ using electrolytes such as NH 4 +, Mg2+, and Al3+. However, the use of NH 4 + was restricted due to ammonia-nitrogen pollution, regarding in-situ leaching agents still remain controversial. It is imperative to comprehensively and systematically investigate the desorption mechanism of rare earth elements (REEs) from a microscopic perspective, especially when using Mg2+ and Al3+ as leaching agents. In this manuscript, the desorption behavior and mechanism of Y3+ from ADY (IREO as adsorbents loaded with Y3+) were studied, along with a comparison of the Y3+ desorption capabilities of Mg2+ and Al3+ as leaching agents. The results showed that Y3+ could be effectively desorbed from IREO by both Mg2+ and Al3+, with Y3+ desorption yields of 93.1 % (pH 3.2, 0.06 mol/L) for Al3+ and 88.6 % (pH 6.0, 0.3 mol/L) for Mg2+, respectively. The superior Y3+ desorption capability of Al3+ arises from its higher valence, greater electronegativity, and smaller ionic radius compared to Mg2+. The higher valence imparts Al3+ greater charge density, while the greater electronegativity enables Al3+ to more readily substitute for Y3+. Additionally, the smaller ionic radius facilitates the entry of Al3+ into clay minerals interlayers. At high H+ concentrations, the Y3+ desorption capabilities of Mg2+ and Al3+ were both higher than at the original pH without acid addition, primarily due to the influence of H+, which could leach Y3+ from the un-exchangeable phase, but also significantly increased the leaching of impurities. The isotherms and kinetics demonstrated the desorption of Y3+ in the case of Mg2+ and Al3+ existing followed the Langmuir and pseudo-second-order models, indicating homogeneous, chemisorption-governed processes. Furthermore, ATR-FTIR, XPS, and DFT results revealed Y3+ desorption occurred by breaking Si O Y bonds and ion exchange with Mg2+/Al3+ to form Si O Mg/Al bonds. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ion-adsorption type rare earths desorption residues as adsorbents. • The maximum Y(III) adsorption capacity of 4.45 mg·g−1. • Y(III) adsorbed onto the adsorbents surface possibly via Sii-Oi-Y bond. • Adsorption process governed by chemical adsorption. Ion-adsorption type rare earths ore, as the primary source for middle-heavy rare earth elements, was extracted by various electrolytes via the adsorption–desorption effect. In this work, adsorption behavior and mechanism for yttrium ions onto ion-adsorption type rare earths ore as adsorbents were investigated systematically and comprehensively. The isotherms and kinetics suggested the adsorption of yttrium ions was consistent to Langmuir and pseudo-second-order model, revealing that the adsorption process was homogeneous and primarily governed by chemical adsorption. Maximum adsorption capacity could attain as 4.45 mg·g−1 in pH of 3 with 10 g·L−1 yttrium ions. Moreover, thermodynamics analysis indicated the adsorption process was spontaneous, and random. ATR-FTIR, XPS and DFT results indicated that Y(III) adsorbed onto ion-adsorption type rare earths ore surface possibly via Si-O-Y bond. [ABSTRACT FROM AUTHOR]