Ultrafine Particle Recovery Using Thin Permeable Films.

The selective recovery of ultrafine, <10 μm, particles remains a significant challenge in the minerals industry. Indeed, these particles often report to tailings impoundments, resulting in under-utilization of mined resources and the need for tailings dams. Recently, a technique has been developed offering the potential to selectively recover particles down to <1 μm in size.

Spontaneous formation of an "antidrop".

We have observed, with great surprise, the spontaneous formation of a quite unusual drop. Because of its similarity to the antibubble [(a) Hughes, W.; Hughes, A.

Influence of surfactant on gas bubble stability.

Gas-bubble stability is achieved either by a reduction in the Laplace pressure or by a reduction in the permeability of the gas-liquid interface. Although insoluble surfactants have been shown definitively in many studies to lower the permeability of the gas-liquid interface and hence increase the resistance to interfacial mass transfer, remarkably little work has been done on the effects of soluble surfactants. An experimental system was developed to measure the effect of the soluble surfactant dodecyl trimethylammonium bromide on the desorption and absorption of carbon dioxide gas through a quiescent planar interface.

Solid-solid contacts due to surface roughness and their effects on suspension behaviour.

Solid-solid contacts due to microscopic surface roughness in viscous fluids were examined by observing the translational and rotational behaviours of a suspended sphere falling past a lighter sphere or down an inclined surface. In both cases, a roll-slip behaviour was observed, with the gravitational forces balanced by not only hydrodynamic forces but also normal and tangential solid-solid contact forces. Moreover, the nominal separation between the surfaces due to microscopic surface roughness elements is not constant but instead varies due to multiple roughness scales.