Ultrasonic Dispersion for Iron Recovery from Slime Tailings: Microprocesses Unveiled through Molecular Dynamics Simulations

Chemical dispersion has been commonly used to mitigate the negative effects of ultrafine particles in iron ore concentration processes. However, mechanical solutions such as ultrasound are proving to be more effective and without harmful side effects. This study compared the performance of different dispersants and ultrasound as pretreatments for reverse cationic flotation of goethite-rich slime tailings through sedimentation, dispersion, and flotation tests, along with particle size analysis. Additionally, large-scale molecular dynamics simulations were used for the first time to investigate the effects of ultrasonic shockwaves on mineral particle interactions. The results showed that ultrasonication is a superior pretreatment, enhancing particle dispersion and separation performance, cleaning mineral surfaces, and improving flotation results. Ultrasound achieved an increase in metallurgical recovery of around 9% while using only a dispersant reagent did not reach 5%. Simulations demonstrated the known effects of ultrasound, such as extreme temperature, bubble cavitation, and particle detachment, revealing the crucial microscopic mechanisms involved in particle separation by sonic waves. This study bridges experimental data with computational simulations, offering a comprehensive understanding of ultrasonication's effects on particle separation, paving the way for more efficient and sustainable processing technologies.