Influence of emulsion microbubbles on the flotation recovery of fine-dispersed chalcopyrite

• Emulsion microbubbles (EMBs) stabilize fine chalcopyrite flotation. • X-133 and AERO 7249 form composite shells on bubble surfaces. • EMBs act as nano/micro-collectors for ultrafine mineral particles. • Composite reagents improved chalcopyrite recovery. Improving the efficiency of beneficiation of fine-dispersed copper minerals remains one of the key challenges of modern mineral processing. The aim of this study is to develop highly flotation-active emulsion microbubbles (EMB) generated using a laboratory-scale Vortex intensive agitator (VIA) for the recovery of fine chalcopyrite particles by multicomponent microflotation. The EMB, for example in the form of spherical structures, consist of an air core, a dense frother layer of X-133, and a thin oily collector layer of AERO-7249. Such EMB with sizes smaller than 30 μm exhibit a dual functionality upon collision with fine chalcopyrite particles. The oily collector layer spreads over the surface of fine chalcopyrite particles, hydrophobizing them, while the remaining oil-coated microbubbles adhere to the mineral surface and transport the particles into the froth concentrate. With the depletion of rich ores, the need for flotation of minerals ground to micron sizes increases, which is accompanied by technological difficulties and higher reagent consumption. A promising approach is the use of micro- and nanobubbles, which promote particle aggregation and increase the probability of their interaction with air during flotation. This work examines the features of the formation and application of EMB generated by the VIA. It is shown that EMB possess a dual nature, simultaneously performing the functions of a frother and a collector. Their application ensures intensification of the flotation process, accelerates the rise of particles into the froth layer, and increases the recovery of ultrafine minerals. Experimental results established that the use of EMB in multicomponent microflotation makes it possible to enhance chalcopyrite recovery both in the medium and fine size fractions. The highest recovery was achieved with the application of a composite collector a mixture of AERO 7249 and X-133 in a 1:1 ratio. Operation in the turbo-dispersed mode ensured an increase in chalcopyrite recovery by 18.7 % compared with the use of ultrasonic dispersion alone during the flotation of –20 + 0 µm size class particles. The obtained results expand the understanding of the mechanisms of microbubble interaction with flotation reagents and confirm the prospects of applying EMB in industrial practice. The proposed method of heterogeneous bubble generation has advantages over traditional cavitation approaches and can serve as a basis for the development of new efficient and environmentally friendly flotation technologies.