The Influence of Embedded Properties on the Liberation Characteristics of Macerals in Subbituminous Coal

The utilization pathways of coal macerals exhibit a significant variability. The efficient separation of active and inert components in coal is critical for realizing their high value-added applications. The liberation efficiency of coal macerals directly influences the accuracy of subsequent separation processes. Investigating the influence of embedded properties of inertiniteincluding embedded granularity, embedded morphology, and concatenate particle typeson the liberation characteristics of coal macerals is essential for achieving separation efficiency. This study focuses on the relationship between the embedded properties of inertinite and the liberation characteristics of coal macerals. According to the development situation of coal in China and embedded characteristics of macerals, three sub-bituminous coal samples from different regions of China (Xinjiang Tianchi (TC), Xinjiang Qiuci (QC), and Inner Mongolia (Ordos)), each exhibiting distinct embedded properties, were selected for experimentation. Both ball and rod milling techniques were employed to conduct grinding tests, and the total liberation degree of the coal macerals (the weighted average of the liberation degree of vitrinite and inertinite) was measured at various particle sizes (-0.5 mm) of the ground products. The results demonstrate that coal samples with finer embedded granularity (expressed as equivalent diameter of the area) exhibited a lower total liberation degree at the same ground product size. The observed differences in the embedded morphology (aspect ratio) of coal macerals led to distinct responses to ball milling and rod milling. This research reveals that embedded granularity has the most pronounced influence on the total liberation degree of coal macerals followed by the embedded morphology. The concatenate particle types have the least impact on liberation. These findings provide a theoretical foundation for understanding the differences in liberation characteristics of macerals in subbituminous coals.