Interaction of calcium dioleate collector colloids with calcite and fluorite surfaces as revealed by AFM force measurements and molecular dynamics simulation.

Spherical calcium dioleate particles 1-10 micrometres in diameter were used as atomic force microscope (AFM) probes to measure interaction forces between the collector colloid and calcite and fluorite surfaces. The attractive AFM force between the calcium dioleate spheres and the fluorite surface is strong and has longer range than that predicted by the Deljaguin-Landau-Verwey-Overbeek (DLVO) theory. The repulsive AFM force between the calcium dioleate spheres and the fluorite surface is not in agreement with the DLVO prediction. The results are explained in relation to non-DLVO forces, including the attractive hydrophobic force and the repulsive hydration force. The non-DLVO interactions were confirmed by the different interfacial water structures at fluorite/ and calcite/water interfaces as shown by numerical computation results using molecular dynamics simulation.
Spherical calcium dioleate particles 1-10 micrometres in diameter were used as atomic force microscope (AFM) probes to measure interaction forces between the collector colloid and calcite and fluorite surfaces. The attractive AFM force between the calcium dioleate spheres and the fluorite surface is strong and has longer range than that predicted by the Deljaguin-Landau-Verwey-Overbeek (DLVO) theory. The repulsive AFM force between the calcium dioleate spheres and the fluorite surface is not in agreement with the DLVO prediction. The results are explained in relation to non-DLVO forces, including the attractive hydrophobic force and the repulsive hydration force. The non-DLVO interactions were confirmed by the different interfacial water structures at fluorite/ and calcite/water interfaces as shown by numerical computation results using molecular dynamics simulation.