A fundamental study of mica flotation in dodecylamine collector

The batch flotation response of mica in dodecylamine solution was related to foam film experiments where the stability, thickness, and interfacial potentials at the air/dodecylamine solution interface was determined. These results were compared with surface force data (reported in an earlier publication) in which hydrophobic adhesion (pull-off force), adsorbed film thickness, and the interaction between molecularly smooth mica sheets in the amine collector solution was determined. The data covered a range of pH values. Maximum flotation occurred at pH 8 and correlated to a tightly packed hydrophobic collector monolayer giving maximum hydrophobicity to the mica surface. From extended DLVO theory, it was shown that heterocoagulation between the bubble and the mica could only occur providing there was a very long range hydrophobic interaction force to counterbalance the repulsive van der Waals and electrostatic forces.