Insights into the roles of interfacial micro/nano bubbles on mineral surfaces and their implications on fine chalcopyrite flotation

The effects of interfacial micro/nano bubbles (IMNBs) in the flotation system seem contradictory due to their dual roles of negative “clean surface reagent” and positive “increase apparent size”. This study generates IMNBs on the mineral surface using the sudden ambient pressure drop method, and investigates the relationship between IMNBs and collector. Microflotation results show that the chalcopyrite flotation recovery was enhanced with IMNBs by the range of 3.42 %∼24.08 % and reached ∼90 % when applying the 81 kPa depressurization amplitude. The magnitude of depressurization positively correlated with these effects, with the order of significance being 81 kPa > 66 kPa > 0 kPa. The collector dosage decreased by 50 % with the optimal flotation condition, confirming the positive results of IMNBs’ application in flotation. Further detection results indicate that a large amount of collector adsorbed onto the IMNBs’ surfaces rather than the chalcopyrite surface after the generation of IMNBs. In addition, IMNBs could promote the agglomeration of fine particles and enhance the adhesion possibility between the fine particles and flotation bubbles. The chemisorption of DDTC onto the chalcopyrite surface in normal conditions and the adsorption remains strong even after the pressure reduction. Thus, the IMNBs still play positive roles in the fine chalcopyrite flotation despite the reduction of collector adsorption amount on the mineral surface. This study is expected to improve the understanding of IMNBs’ effects in the field of mineral flotation.