Applying an Atomic Force Microscopy in the Study of Mineral Flotation

An atomic force microscopy (AFM) has been applied to study in situ the adsorption of chemicals on minerals, i.e. chalcopyrite and molybdenite, in aqueous solution. The AFM images showed that some absorbate in patches was detected on the chalcopyrite surface, after the mineral sample was soaked in 5x10-4M potassium ethyl xanthate (KEX) solution at pH 11 for 10 minutes. The absorbate can be removed from the chalcopyrite surface by rinsing with ethanol. On the other hand, the AFM images obtained with molybdenite in solutions showed that the absorbed chemicals on molybdenite surface were very sparse. The findings clarify that, in industrial flotation practice, KEX and its homologues are widely applied for chalcopyrite flotation; on the other hand, hydrocarbon oil, rather than KEX, is generally used as the promoter of molybdenite flotation. The results also show that an AFM can be a powerful tool for the fundamental study of the adsorption of chemicals on mineral surface in froth flotation.