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Surfactants are usually used as grinding aids. However, surfactant foaming during the grinding process is rarely mentioned in the literature with no clarification of its effect on the grinding process. In this paper, the generation of foam during the grinding of talc and quartz, as two different minerals in their hardness and hydrophobicity, was observed in the presence of sodium dodecyl sulfonate (SDS). The effect of generated foam on the fineness of ground product under different grinding conditions such as solids%, grinding time, and pulp pH was investigated. The results indicated that the foam was formed during the grinding of both minerals. The foam volume depends not only on the presence of surfactant but also on the characteristics of the mineral along with grinding conditions. The foam was intense and more stable particularly at pH 10 and high solid content (i.e., 60% solids) in the case of talc due to its fineness and hydrophobicity that result in bubbles stabilization. Remarkably, there is no foam at acidic pH due to the high ionic strength that leads to bubble instability. Most importantly, the presence of surfactant foams improves the size reduction process by providing more dispersion of particles, as one of the grinding aid mechanisms, due to particle‐particle and particle‐SDS repulsive electrostatic forces. [ABSTRACT FROM AUTHOR]

Talc processing starts with grinding followed by flotation. The flotation feed preparation significantly affects the concentrate quality. In this study, the preparation of talc flotation feed by grinding was investigated in the absence and presence of sodium dodecyl sulfonate (SDS), one of the well-known flotation reagents. The natural floatability of talc was compared to its floatability after adding the SDS in either grinding or flotation. The results proved a significant effect of grinding conditions on its natural floatability. The higher flotation recovery is achieved by grinding at the alkaline medium compared to the acidic medium at 30% solids. More interestingly, adding the SDS in flotation produced a higher talc recovery than that the achieved recovery by its flotation after adding SDS in grinding although it has more chance for mixing the reagent with particles and adsorption of SDS to talc particles. Thus, the tested variables in grinding tests negatively affect the SDS effectiveness as a flotation reagent for talc. [ABSTRACT FROM AUTHOR]

Invasion of fluids into porous media during drilling can lead to irreparable damage and reduced well productivity. Hence, minimizing the filtration loss of the drilling fluid into the formation is very important. The stability of colloidal suspensions plays a crucial role in controlling the interfacial forces and consequently on minimizing the filtration. The zeta potential is an indicator of the stability of colloids with respect to their electrostatic interactions. In this study, the rheological properties of bentonite suspensions are investigated with and without additives. The starch and CMC were used as additives to enhance the rheological properties of bentonite. The effects of these additives on the drilling fluid filtration were examined. Zeta-potential, viscosity, gel strength and yield point were measured to characterize the extent to which control of the filtration loss of the drilling fluids can be achieved. The zeta-potential and the amount of filtration loss of water-bentonite suspensions were correlated. Finally, the results showed that the addition of either starch or carboxymethyl cellulose (CMC) enhances the filtration properties of water-bentonite suspensions. [ABSTRACT FROM AUTHOR]