Effect of Forced Shear Sliming and Slime Removal on the Flotation and Particle–Bubble Mineralization of Lignite

Slime generally should be avoided in the coal flotation process. However, lignite exhibits a tendency for sliming under a flotation liquid-phase disturbance environment. This study innovatively proposes a high-efficiency lignite flotation strategy based on forced shear-induced sliming and preliminary desliming. This approach employs external shear forces to dissolve and disperse gangue minerals in lignite, which are then preremoved prior to flotation. Results demonstrate that the flotation clean coal yield increased from 17.25-36.65% to 39.92%∼55.71%, while the clean coal ash content decreased from 13.8-16.5% to 9.25%∼12.8%, improving lignite upgrading effect. Further characterization revealed that the lignite surface became smoother after sliming and slime removal treatment, which may create favorable flotation interface conditions. The observed larger particle-bubble adhesion angle directly confirms that the sliming and slime removal process promotes particle-bubble mineralization. Therefore, this may be a viable industrial lignite flotation method.