Molecular dynamics simulation of aluminum inhibited leaching during ion-adsorbed type rare earth ore leaching process

Molecular dynamics simulation was adopted to study the interaction between sulfosalicylic acid and aluminum, lanthanum and yttrium, and adsorption on kaolinite surfaces. A complexation reaction occurs between sulfosalicylic acid and aluminum, with an interaction energy of -10472.05 kJ/mol. O-Al covalent bonds are formed with a peak value of 7.93, while there is only weak adsorption between sulfosalicylic acid and rare earth ions. A hydrogen bonding reaction with 13605.82 kJ/mol energy occurs between sulfosalicylic acid and the surface of kaolinite (100). Thus, sulfosalicylic acid can form a complex with free aluminum ions, and can also be adsorbed on kaolinite by hydrogen bonding with aluminum in kaolinite (100) surfaces. Leaching of ion-adsorbed type rare earth ore was performed with aluminum inhibited, results show that when sulfosalicylic acid dosage increases from 0 to 0.15 wt%, aluminum ion concentration in the leaching solution decreases from 273.23 to 47.19 mg/L. And the effect of leaching pH value on the effect of sulfosalicylic acid on aluminum inhibition was studied, the result shows that, when the leaching pH value is 4.0-5.0, the rare earth leaching rate and the aluminum ion concentration basically remain unchanged. The molecular dynamics simulation results were verified by detection and analysis of XPS and SEM. (C) 2019 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.