Characterizing mineral wettabilities on a microscale by colloidal probe atomic force microscopy

For finely intergrown ores the characterization of reagent-mineral interactions in flotation systems holds difficult challenges for the applicability of standard techniques like hallimond tube tests or contact angle experiments or renders them impossible while other techniques might not work in an aqueous environment. We present the utilization of an atomic force microscope with a hydrophobic colloidal probe to characterize the wettabilities of individual mineral grains on a microscale. The sulfidic ore sample containing chalcopyrite, pyrite and quartz is investigated in an aqueous environment. The mineralogy of the sample is characterized by SEM+EDX and its wettability by contact angle measurements. Force mappings on the respective minerals are performed and allow a distinction between quartz, chalcopyrite and pyrite with the resulting force distributions. An additional focus in this paper lies on the heterogeneities within one mineral surface domain and the applicability for grain mappings.