A density functional theory (DFT) on the leaching process of weathered crust elution-deposited rare earth ore with lixiviants

Abstract

The properties of the solution are closely related to their structures. For efficient exploitation of the weathered crust elution-deposited rare earth ores, the properties of RE ions of the solution have been studied in the leaching process of weathered crust elution-deposited rare earth ores. The structures of 10 hydrated RE clusters were optimized at the PBE0/6-311+G(d, p) level by density functional theory (DFT). The electrostatic potential distribution, the interaction, and the binding energy of hydrated RE clusters with different anions were analyzed. The effect of the anion of the lixiviant in the leaching process was studied at the molecular level. The results show that thermodynamics dominates the static leaching of rare earth (RE) in the leaching process. In the leaching of REs from weathered crust elution-deposited rare earth ore, the stability of the hydrated clusters can affect the leaching rate. The anions that form more stable hydrated clusters with RE ions are more conducive to rare earth leaching. The interaction between inorganic anion and water can also reduce the energy of the whole cluster and make the structure more stable. Besides, the binding energy of the clusters indicates that hydrated clusters with heavy REs have lower binding energy than those with light REs. So the heavy REs are more likely to migrate with the solution. This conclusion also fits with the fractionation effect of rare earth partition.