Improvement of fine muscovite flotation through nanobubble pretreatment and its mechanism

[Display omitted] •Fine muscovite particle flotation pretreated by nanobubbles was investigated.•Nanobubbles improved the flotation recovery of the fine muscovite.•Nanobubbles reduce the dosage of reagents.•Nanobubbles reduced the induction time of muscovite.•Nanobubbles can agglomerate muscovite particles. With the increasing demand for mineral resources, it is necessary to further recycle some fine muscovite which are not of high quality and discarded after the first development. This study was to improve the recovery of fine muscovite (−20 μm) by introducing of nanobubbles (NBs). A series of techniques including flotation test, mineral adsorption capacity measurement, Zeta potential measurement and the visualization of mineral and bubble interaction were used to investigate the flotation effect of NBs pretreatment on fine muscovite. The results showed that in the dodecylamine (DDA) flotation system, the flotation recovery of fine muscovite pretreated by NBs was higher than that without NBs pretreatment under any concentration of collector and flotation recovery was increased by about 7 %. Meanwhile, the dosage of reagent was reduced by 25 % at the same recovery. NBs pretreatment could reduce the adsorption capacity of DDA and electrostatic repulsion of the muscovite particles, which was beneficial to form particle agglomeration. In addition, the three-phase contact line of the muscovite pretreated with NBs could be formed faster (34 ms). Furthermore, the trajectory of muscovite particles pretreated by NBs were closer to bubbles, and easier to form obvious agglomeration. The introduction of NBs can enhance the flotation of fine muscovite, which provide a cost-effective approach for the fine particle flotation.