This study investigated the influence of bulk nanobubbles (NBs) on the flocculation and filtration behavior of kaolin suspensions treated with cationic polyacrylamide (CPAM). Traditionally, flocculation relies on bridging mechanisms by polymers like CPAM. The present work examines the possibility of combining NBs with CPAM to achieve more efficient kaolin separation. The settling behavior of kaolin suspensions with and without bulk nanobubbles was compared. The results with 2 mL CPAM and 300 s settling time revealed that bulk NBs significantly enhanced flocculation efficiency, with supernatant zone height reductions exceeding 50% compared to CPAM alone, indicating a faster settling rate resulting from bulk NBs. This improvement in the settling rate is attributed to NBs’ ability to reduce inter-particle repulsion (as evidenced by a shift in zeta potential from −20 mV to −10 mV) and bridge kaolin particles, complementing the action of CPAM. Additionally, the study demonstrated that bulk NBs improved dewatering characteristics by lowering the medium resistance and specific cake resistance during filtration. These findings pave the way for the utilization of bulk NBs as a novel and efficient strategy for kaolin separation in mineral processing, potentially leading to reduced processing times and lower operational costs.

The flotation effect of lean coal is crucial for its clean utilization. Therefore, the flotation characteristics of difficult-to-float lean coal were studied. The analysis results of the feed properties showed that the ash content of the feed was high and the particle size was very fine. The minerals in the gangue mainly included sericite, kaolinite, quartz, white mica, and other substances. After flotation, the functional groups of the coal particles in the tailings decreased, and the absorption peak intensity weakened. Furthermore, the results of multi-factor flotation experiments showed that the dosages of the collector and the frother were significant factors affecting the yield of clean coal. The clean coal yield gradually increased with an increase in the two factors. The ash content of the clean coal increased with an increase in the frother dosage. Within the range of feed concentrations used in this work, the feed concentration was not a significant factor affecting the clean coal’s yield and ash content. Prediction models for the clean coal yield and ash content were proposed. Under optimized experimental conditions, the clean coal yield and the flotation perfection index were 72.15% and 46.63%, respectively, indicating a good flotation effect.