Wettability of Mineral Surfaces
Introduction
Mineral wetting is an important and complex phenomenon related to the interactions between a solid surface, liquids, and gas phases. The wettability of a mineral surface is defined as its ability to spread and form a thermodynamically stable interface. Generally, wetting is characterized by a measure of the strength of contact angle between fluid and the solid surface. The contact angle between fluid and the solid surface can be used to calculate the wetting strength, which is related to the surface energy of a particular solid and the interfacial tension between the components of a liquid-liquid or liquid-gas system.
In this paper, the wettability of different mineral surfaces and the factors which determine their wettability are discussed. The properties which can be used to describe the wettability of a mineral surface include the surface energy, surface chemistry, surface structure, and surface topography.
Surface energy
The surface energy of a mineral surface is a measure of its overall energy which is related to the strength of interaction between particles in the bulk phase and particles on the surface. The surface energy of a mineral surface can be determined by a variety of techniques including surface electron microscopy, matrix-dependent techniques such as X-ray diffraction, and surface electron spin resonance. The surface energy is probably the most important factor in determining the wettability of a mineral.
Surface chemistry
The surface chemistry of a mineral is closely related to its surface energy. The surface of a mineral may be thought of as composed of layers of positively and negatively charged atoms and molecules. These layers interact with the relevant species in the liquid which can alter the wettability of the surface.
Surface topography
The wettability of mineral surfaces is also related to their surface topography. The surface roughness of a mineral can affect its wettability by increasing the number of contact points between the fluid droplet and the mineral surface. The average number of contact points can be determined by measuring the projected area of a droplet on a surface which is known as the contact area. The contact area is related to the surface energy of the mineral surface and is an important parameter which can be used to determine the wettability of a mineral.
Surface roughness
The surface roughness of a mineral is related to its surface energy and surface contact area. The surface roughness of a mineral can be assessed by a number of techniques including electron microscopy, atomic force microscopy, and scanning tunneling microscopy. The surface roughness of a mineral can influence its wettability by increasing the number of contact points between the fluid droplet and the mineral surface.
Conclusion
The wettability of a mineral surface is an important characteristic which is related to its surface energy, surface chemistry, surface structure and surface topography. The surface energy of a mineral surface influences its wettability by providing a measure of the strength of interaction between particles in the bulk phase and particles on the surface. The surface chemistry of a mineral can also affect its wettability by influencing the interaction between the relevant species in the liquid and the surfaces of the mineral. Furthermore, the surface topography of a mineral affects its wettability by providing a measure of the projected area of a droplet on its surface. Finally, the surface roughness of a mineral influences its wettability by increasing the number of contact points between the fluid droplet and the surface.
