Role of hydrolyzed cations in the natural hydrophobicity of talc

Effects of Metal Ions on the Flotation of Apatite, Dolomite and Quartz

“…This was caused by the compression of the electric double layer. In this case, the Ca 2+ ions were mobile in the diffuse layer and not adsorbed in the Stern plane and fixed on the solid surfaces [23]. Therefore, they could not help quartz to adsorb carboxylates.…”

“…Therefore, Al 3+ and Fe 3+ were in the form of insoluble metal hydroxide throughout the pH range of micro-flotation tests. Al(OH) 3 and Fe(OH) 3 could preferentially precipitate on the mineral surface [23], and the hydrophilicity of apatite and dolomite was enhanced, resulting in the reduction of the adhesion of surfactant molecules on the mineral surface. That is why the floatability of apatite and dolomite decreased in the presence of Al 3+ and Fe 3+ , as shown in Figures 2 and 3.…”

Assessment of the Surface Heterogeneity of Talc Materials

“…Nevertheless, as expected, the relative value of hydrophilic surfaces determined in this way is overvalued. The variation of the electrophoretic mobility µ of the talcchlorite particles with the pH indicates that the sign of the global electrical surface charge of the particles is negative for pH's greater than 3 (17). However, most clay minerals will exhibit a heterogeneous surface and even though the talc surface is negatively charged from a macroscopic point of view, broken edge faces may carry some positive surface sites.…”

“…Flotation of talc particles in water, without wetting agents, qualitatively shows their natural hydrophobic character, which is related to their sheet structure and especially to the basal plane areas containing siloxane bonds exhibiting hydrophobic character (16)(17)(18)(19). The edge surfaces, resulting from the breaking of the sheets during grinding, are hydrophilic due to the occurrence of OH groups (essentially silanol) and thereby show properties very similar to those of other hydrophilic oxide minerals.…”

Adsorptive bubble separation of zinc and cadmium cations in presence of ferric and aluminum hydroxides

“…This is why the adsorption of metal cations and surfactants should be considered as an interaction with these groups. Based on the theory of site binding (theory of the formation of an electrical double layer at the precipitate-solution interface), these interactions can be described as a process of release of the hydrogen cations from the surface hydroxyl groups by the metal cations (or in virtue of processes of both adsorption and dissociation of H + from the surface hydroxyl groups and adsorption of the metal cations) [12][13][14][15][16][17][18][19][20]. Due to these processes the precipitate surface in water is covered with three kinds of surface groups: =SOH + 2 , =SO − , and =SOH.…”