THE SURFACE-PROPERTIES AND FLOTATION BEHAVIOR OF XENOTIME

Surface properties and flotation behaviour of xenotime using sodium ol eate as a collector have been investigated. Adsorption isotherm and fl otation studies in combination with chemical modelling were conducted to investigate the surface properties of xenotime and mechanisms of th e interactions of the surface with the collector and the collector-tre ated surface with air bubbles. It was found that the adsorption proces s on a xenotime surface is very much pH dependent. The amount of activ e sites on the surface available for reacting with the collector is re lated to the distribution of hydroxyl species. From both experimental observations and chemical modelling, surface precipitation is believed to play an important role in governing the mechanisms of flotation in acidic and alkaline media. Surface preciptation may render the minera l surface more hydrophilic. From the adsorption isotherm at 25-degrees -C, the orientation of oleate molecules was found to be vertical, havi ng a cross-sectional area of 21 angstrom2. On the other hand, at a hig her temperature of 70-degrees-C, the cross-sectional area changed to a higher value of 42 angstrom2, indicating a combination of vertical an d flat orientations.