Abstract: To further improve the separation effect of coarse coal slime and solve the problems of obvious particle size effect, insufficient separation precision, high lower separation limit, and complex process systems in existing equipment, a separation concept dominated by dynamic buoyancy is proposed based on the analysis of the working principles, application defects of mainstream equipment, and the influence laws of multi-field forces on mineral particle motion. It is clarified that dynamic buoyancy consists of interparticle forces and pore water pressure. Based on this mechanism, an experimental prototype was designed, and laboratory separation tests were carried out on raw coal slime, tailings of middlings/refuse magnetic separators, coarse coal slime, and small raw coal with different properties from several domestic coal preparation plants. The results show that dynamic buoyancy-dominated separation can achieve high-efficiency separation of small coal with particle size < 8 mm, featuring high separation precision, low fine slime contamination in clean coal, and low misplaced material content. The effective lower separation limit reaches 0.074 mm, the probable deviation for the 1～0.074 mm size fraction is 0.09 g/cm³, and the ash reduction in each size fraction is significant, with the maximum ash difference between light and heavy products reaching 49.08 percentage points. The dynamic buoyancy-dominated separation mechanism can weaken the influence of particle size, requires no heavy media, significantly improves the separation effect of coarse coal slime, simplifies the dehydration and recovery process, expands the effective separation size range, and achieves high-precision separation of wide-size-range fine materials.