Abstract
Efficient deashing of low-rank coal is challenged by complex mineral-organic intergrowth, often limiting the efficacy of conventional gravity separation. This study investigated two Inner Mongolian coals (ZN and SW) through three pathways: raw coal separation, size-fraction separation (3–0.5 mm), and integrated grinding (+3 mm) with centrifugal separation. Results indicated that while controlled grinding promoted mineral liberation in ZN coal, SW coal was prone to over-grinding and fine-particle agglomeration. The integration of grinding with centrifugal separation yielded the most significant deashing effect, in the <1.3 g/cm3 fraction, ash content decreased from 11.49% (Mixed) to 9.43% (Centrifugal Mixed) for ZN coal and from 4.89% to 4.33% for SW coal. Logistic simulations further confirmed that the centrifugal approach produced sharper partition curves and reduced misplaced material, particularly for the mineral-complex ZN coal. These findings demonstrate that 3 mm classification combined with targeted grinding and centrifugal enrichment significantly enhances separation efficiency, providing a theoretical framework for the clean utilization of low-rank coals.