[Spatial Distribution Characteristics and Graded Utilization Path of Coal Gangue in China].

Abstract

China produces 600-800 million tons of coal gangue annually, and the utilization rate is maintained at approximately 70%, while the cumulative storage has reached 60-70 billion tons and is still increasing year by year, posing potential environmental risks. Because of the different lithology and mineral composition of coal-bearing strata deposited in different coal-forming stages, the properties of coal gangue exhibit significant regional differences. However, the current research and utilization process pays less attention to the regional heterogeneity of coal gangue, becoming a key issue restricting further increase in the utilization rate of coal gangue. From the perspectives of industrial policies, spatial heterogeneity, and technological potential, the current utilization status and utilization potential of coal gangue were systematically analyzed in this study, leading to the proposal of a regionalized grading and utilization scheme for coal gangue. The results indicate that, in the key directions encouraged for coal gangue utilization, because of economic and utilization constraints, policies and related research have gradually been shifting from focusing on power generation and production of building materials to eco-friendly disposal techniques such as underground filling and land reclamation. Over the past decade, the comprehensive utilization rate of coal gangue has increased from 61.9% to 72.2%, with the main growth contribution coming from filling disposal, while utilization in power generation and building material production has remained stable at 21.6% and 7.5%, respectively. Eco-friendly disposal of coal gangue will be the main growth point for its utilization nationwide. In regions with large coal gangue production, such as Shanxi, Shaanxi, and Inner Mongolia, where coal gangue concentration is high, comprehensive utilization plans focusing on filling disposal as the primary method and processing utilization as secondary should be established. Among these regions, Inner Mongolia's coal gangue mainly consists of alumina-rich rock gangue, which should be prioritized for alumina extraction and building material production； Shanxi's coal gangue is mainly sandstone gangue with high calorific value, suitable for power generation and building material preparation； the coal gangue in the eastern region mainly comprises claystone and calcareous rock gangue, with relatively low production levels, and the local building material market is sufficient to cover the gangue output, making it a priority utilization direction； and in some mining areas in Shandong and Hebei, where the proportion of coal mining under "three conditions" is relatively high, extending the service life of mines can be achieved through "coal-for-gangue" substitution, with a focus on the development of underground filling technology.