Complexation and activation of fluoride ion and its acceleration for dissolution of cations on the surface of vanadium-containing biotite (002)

Density functional theory (DFT) calculations are used to simulate the interaction between leaching agent ions (H+), complexing agent ions (F-), and a vanadium-containing biotite surface. The calculation results show that the active sites for adsorbing leaching agent ions are oxygen atoms, and the final product is water. The formation of surface water molecules leads to defects in surface oxygen atoms, and such defects lead to the isolation and dissolution of cations on the surface. The active sites for adsorbing complexing agent ions are surface cations. The adsorption of complexing agent ions can destroy the tetrahedral structure of surface cations and can also reduce the activation energy required to form surface water molecules. The two oxygen atoms connected to the vana-dium element generate water, and the activation energy is decreased from 5.89 eV and 6.83 eV to 2.32 eV and 3.85 eV, respectively. When the cation is exposed, the fluoride ion can complex with the exposed cation and enter the solution to achieve the dissolution effect. This research is problem-oriented and involves experiments and a deep understanding of the mechanism for ion activation leaching on the atomic level. It has been confirmed that the complexing agent ion proposed in this work can greatly increase the leaching rate, as has been verified by electron probe, scanning electron microscopy, infrared and other methods. The reliability of simulation calculations.

Automated summary

In this study, density functional theory (DFT) calculations were used to simulate the interaction between leaching agent ions, complexing agent ions, and a vanadium-containing biotite surface. It was found that oxygen atoms were the active sites for adsorbing leaching agent ions, resulting in the formation of water as the final product. The formation of surface water molecules led to defects in surface oxygen atoms, which caused the isolation and dissolution of surface cations. Complexing agent ions were found to be adsorbed on surface cations, disrupting their tetrahedral structure and reducing the activation energy required for the formation of surface water molecules.