Collecting behaviors of high internal phase (HIP) emulsion in flotation of ultrafine high-ash content coal slime

In order to tackle the problems of high oily collector consumption and low separation efficiency associated with ultrafine coal slimes, a new collector named high internal phase (HIP) emulsion was prepared. The flotation results showed that the HIP emulsion could significantly reduce the oil consumption by 90% compared with kerosene. The superior performance of HIP emulsion compared to kerosene was attributed to its higher flocculation ability, which was supported by the kinetic flocculation experiment and the Extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory calculation. The preconditioning experiment showed that the high-shear pulping could greatly promote the overall flotation rate of HIP emulsion, which was due to the enhanced dispersion of the pasty HIP emulsion in the slurry as confirmed by the rheological measurement. The degradation of flocculation ability of HIP emulsion during high-shear stirring may be attributed to the microstructure damage as supported by the conductivity experiments. The HIP emulsions were proved as a potential economic and efficient collector for the beneficiation of ultrafine and high-ash content coal slimes.