Effect of fine slime on lignite flotation: focusing on particle-bubble mineralization and separation kinetic

Lignite has a pronounced tendency to slime when in contact with water, generating substantial amounts of high-ash fine slime that adversely impact the quality of clean coal during flotation and lead to increased reagent consumption. This study systematically investigates the influence of desliming efficiency on the flotation performance of Shengli lignite, with desliming efficiencies of 0%, 20%, 40%, 60%, 80%, and 100% being examined. The results indicate that desliming significantly enhances flotation performance by improving slurry fluidity, reducing ash content, and promoting particle-bubble attachment. At 100% desliming efficiency, the clean coal yield increased from 38.48% to 56.12%, slurry viscosity decreased from 4.02 to 1.68 mPa<middle dot>s, and the particle-bubble wrap angle improved from 60 degrees to 146 degrees, reflecting enhanced hydrophobicity and stronger adhesion. Flotation kinetics analysis demonstrated that a 20% desliming efficiency achieved the highest flotation rate constant (k = 2.2041) and optimal froth stability, characterized by a froth height of 14.3 cm and a decay time of 9.43 s. However, excessive desliming reduced froth stability and flotation rates. These findings underscore the critical role of desliming in optimizing flotation efficiency, offering practical insights for industrial processes, and supporting the sustainable utilization of lignite resources.