The effect of size separation by cyclosizing and sedimentation/decantation on mineral surfaces

Particle size dramatically influences the flotation behaviour of galena. The part that differences in surface chemistry play in this effect is not yet clear. Experiments were designed to examine the surface chemistry of size fractions prepared from lead rougher feed pulp from Aberfoyleʹs Hellyer operation. However, the effects of the sizing technique employed on the surface properties of the particles were found to be significant. Lead rougher feed was sized using two commonly available techniques. cyclosizing and sedimentation/decantation. Similar size fractions prepared by the two methods were examined using bulk assays (XRF) in conjunction with scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS) to identify differences in aggregation and surface characteristics. servations show that the cyclosizer produced particles free of attached fine particles (i.e.slimes coatings) due to the high shear environment. The sedimentation/decantation process yielded particles covered with attached fine particles as shear rates were essentially zero. The high shear present in the cyclosizer resulted in surfaces that were sulphide rich, whilst the sedimentation/decantation procedure, over periods up to 24h, produced surfaces that showed high levels of oxidation.