Use of a natural rock material as a precursor to inhibit corrosion of Ti alloy in an aggressive phosphoric acid medium.

The mechanism of interaction between magnesite mineral and phosphoric acid (0.001-0.5 M) in addition to the determination of the protective properties for Ti alloy (working electrode) in phosphoric acid both with and without an inhibitor have been investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements.

Adsorption mechanisms of fatty acids on fluorite unraveled by infrared spectroscopy and first-principles calculations.

Hypothesis: The adsorption mechanisms of fatty acids on minerals are largely debated from years, and their understanding is now required to improve flotation processing in the critical context of raw materials. Three wavenumbers have been observed in the literature for the asymmetric stretching vibration of COO after the adsorption of fatty acids on mineral surfaces. They have been interpreted as different adsorbed forms, such as a precipitate formation, an adsorption of sole or bridged carboxylates, an anion exchange, or adsorbed modes, such as monodentate or bidentate configurations.

Synergistic adsorptions of NaCO and NaSiO on calcium minerals revealed by spectroscopic and molecular dynamics studies.

The synergistic effects between sodium silicate (NaSiO) and sodium carbonate (NaCO) adsorbed on mineral surfaces are not yet understood, making it impossible to finely tune their respective amounts in various industrial processes. In order to unravel this phenomenon, diffuse reflectance infrared Fourier transform and X-ray photoelectron spectroscopies were combined with molecular dynamics to investigate the adsorption of NaSiO onto bare and carbonated fluorite (CaF), an archetypal calcium mineral. Both experimental and theoretical results proved that NaCO adsorbs onto CaF with a high affinity and forms a layer of NaCO on the surface.

Molecular Insight into Fatty Acid Adsorption on Bare and Hydrated (111) Fluorite Surface.

The adsorption of fatty acids with various chain structures on the (111) fluorite surface is investigated using density functional theory, including a correction for dispersive interactions. In the case of the acidic form, we observe that the molecular form is preferred over the dissociated one and the molecule adsorbs on a surface calcium atom with an energy of -78.2 kJ mol.

Surface Properties of Fluorite in Presence of Water: An Atomistic Investigation.

Density functional theory simulations, including a correction for dispersive interactions, were performed to investigate the adsorption of water on the main cleavage plane of the fluorite, namely, the (111) surface. In the case of a single molecule of water, we observe that the molecular form is preferred over the dissociated one, and absorbs on the surface with an energy of -55 kJ mol, including a significant contribution from the dispersion forces. Also, we show that the substitution of a fluorine atom by a hydroxyl group on the surface of fluorite is not energetically favorable.