Quantum chemical calculations and molecular dynamics simulations of amine collector adsorption on quartz (0 0 1) surface in the aqueous solution

In this study, density functional theory (DFT) calculations are used to investigate the structure-reactivity relationship of dodecylamine (DDA), dodecyl-propyl ether amine and fatty amine ethoxylate (AC1201) molecules as flotation collectors for quartz. The results indicate that these collectors have difficulty forming a covalent bond with the silicon atom on the mineral surfaces, while their protonation species can easily adsorb on quartz surface through electrostatic attraction. Molecular dynamics (MD) simulation has been used to study the adsorption of amine derivative collectors on quartz surfaces at a molecular level. In the consideration of solvation effect, a model close to the realistic flotation system is fabricated. Interaction energies for collector-quartz surface have been determined, based on which, AC1201 is found to be the most effective collector. Trend as obtained from the molecular modeling has been validated by microcalorimetry measurements and flotation studies on quartz with DDA, ether amine and AC1201 at different pH and collector concentrations.