Effect of grinding methods on slime dissociation characteristics and flotation kinetics of coking coal

Despite extensive research on the connection between coal flotation kinetics and particle size, little is known about the shape effect. To fill this gap, this study aims not only to explore dissociation characteristics and particle shape properties resulting from the grinding of coking coal in a planetary ball mill (PBM) and a vertical shaft impact crusher (VSIC) but also to investigate their effects on flotation kinetics. Moreover, for the first time in the literature, shape, kinetic rate constant, and bubble loading capacity (hydrophobicity) properties of coking coal products ground in two different mills were compared by shape characterization, flotation kinetics, and single bubble loading tests, respectively. The findings are: (1) Compared to PBM, VSIC produced rounder-shaped particles with a better communition selectivity, (2) Since PBM's flotation rate constant values (Km) were higher than VSIC's, the particles produced by the PBM exhibit a favorable aspect ratio for faster flotation. [Display omitted] •Grinding effic.(VSIC) > Grinding effic.(PBM), Selectiv.(VSIC) > Selectiv.(PBM).•Km decreased as the particle size decreased, Km(PBM) > Km(VSIC).•AR(PBM) > AR(VSIC),Rn(VSIC) > Rn(PBM).•Bub. Load. Cap. (low ash & high AR) > Bub. Load. Cap. (low ash & low AR) > Bub. Load. Cap. (high ash & high AR)•The higher the AR the better floatability, and the faster recovery.