Anti-adsorption mechanism of ion-adsorption type rare earth tailings

To investigate the process of RE3+ anti-adsorption on ion-adsorption type rare earth tailings, the thermodynamics, adsorption kinetics and infrared spectroscopy of these materials were investigated. The results indicate that the initial reaction rate of anti-adsorption of rare earth tailings is fast, but it reaches a balance in 6 min. The formula 1 − 2a/3 − (1 − a)2/3 = k2t (k represents rate constant of the reaction, a represents anti-adsorption rate of rare earth ore, t represents anti-adsorption time) of internal diffusion can be used to predict the kinetics of anti-adsorption in IATRE tailings. Because ΔH < 0, ΔG < 0, ΔS > 0 (ΔH, ΔG, ΔS represent change of enthalpy, Gibbs free energy and entropy, respectively), the anti-adsorption of RE3+ on ion-adsorption type RE tailings is a spontaneous physical adsorption process. The effects of ligand exchange and strong chemical bond are not found in this process. Because the anti-adsorption process is exothermic, heating will inhibit the reaction and decrease the anti-adsorption performance. According to the infrared spectrum analysis, there are no significant changes in the mineral surface after anti-adsorption. Based on these findings, the anti-adsorption of rare earth tailings is physical adsorption.