Attachment of non-spherical particles to the fluidic surface – Experiment and direct numerical simulations

The attachment of colloidal particles to the fluidic surface of immersed fluid droplets is central to a wide variety of industrial applications, among which stand out the recovery of minerals by gas bubbles, a process known as flotation. The flotation process involves the attachment of hydrophobised colloidal particles to the surface of rising air bubbles, while the commercially valueless hydrophilic material settles down the cell. Experimental and numerical works dealing with the attachment of non-spherical particles to a fluidic interface are here presented. Using an optical microbubble sensor the various microprocesses associated with the colloidal attachment of elongated fibers are first investigated. In a second stage direct numerical simulations are used to predict the dynamics of such particles at a fluidic interface. Unlike spherical particles, it is found that plate-like particles attach more rapidly to a fluidic interface and are subsequently harder to dislodge when subject to an external force.