Comparative study on hydration shell structure and wettability characteristics of Quartz, Feldspar, and muscovite surfaces

Abstract

Solid–liquid interfaces of silicate minerals, particularly mineral–water interfacial interactions, have been found to directly influence the processes of mineral material modification, ion transport, and flotation separation. We systematically investigated the effects of surfactants on the hydration shells of quartz, feldspar, and muscovite based on large-scale molecular dynamic simulations, flotation kinetics, and contact angle. Muscovite exhibited a comparatively thicker hydration shell with looser water molecule arrangement and greater hydrophilicity than those of quartz and feldspar, which may lead to a much lower contact angle of 9.48°. The contact angles of the three minerals increased rapidly with the addition of dodecylamine (DDA). However, the adsorption of DDA on the silicate minerals formed holes through its hydrophobic alkyl chains, indicating that the hydration shells would return to their original states after removal of DDA. Feldspar and muscovite had similar flotation constants, whereas those of muscovite and quartz were distinct, which may be attributed to the difference in the adsorption sites of DDA on the minerals and the density and orientation of water molecules in their hydration shells. This study provides a comparative analysis of the hydration shell features between the silicate minerals, establishing a new perspective for understanding the interfacial phenomena in a mineral–aqueous solution.