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.