Study of the difference in floatability between quartz and feldspar based on first principles

Abstract

For the initial time, this research juxtaposes the surface atomic activities of quartz and potassium feldspar, centering on their respective surface atomic relaxation distances. Findings indicate that on quartz surfaces, the primary adsorption locales are unsaturated Si atoms paired with dangling O atoms. Conversely, the feldspar surface’s key adsorption points involve tri-coordinated Al atoms alongside hanging O atoms. Water molecules on feldspar’s Al, K, and O sites form various bonds—covalent, ionic, and hydrogen. On the quartz counterpart, water molecules exclusively interact with Si and O atoms, with each Si atom accommodating a single water molecule, thus rendering the potassium feldspar’s surface more conducive to wetting—a finding corroborated by the contact angle experiments. Within a sodium oleate matrix, oleate anions link to quartz via hydrogen bonds, whereas they attach to feldspar surfaces forming mono-component rings through both covalent and ionic bonding.