Study on correlations of chemical properties and ecological risk assessment of coal gangue

Coal gangue, characterized by vast reserves, substantial emissions, and prominent environmental impact, demands clean and efficient utilization. The chemical properties of coal gangue significantly influence its behavior. However, the quantitative correlations among chemical properties based on large datasets remain unclear. The correlations among chemical properties were quantitatively investigated based on a dataset of over 400 coal gangue samples. The chemical properties of coal gangue exhibit significant regional variations. The majority of coal gangue (~95%) features a fuel ratio between 0 and 1.5. With the increasing fuel ratio, moisture (Mad) and ash contents (Aad) decrease, while fixed carbon content (FCad) and low heat value (Qnet,ad) rise. However, volatile matter (Vad) and sulfur contents (Sad) demonstrate insignificant correlations with the fuel ratio. The ash fusion characteristics of coal gangue are intricately linked to distributions of its ash compositions within the ternary diagram. Manganese (Mn) and zinc (Zn) exhibit considerable fluctuations, ranging from 0 to 1000 mg·kg−1. Cadmium (Cd) and copper (Cu) show significant contamination levels. Notably, Cd also presents a particularly high potential ecological risk, receiving attention in coal gangue management strategies. This research provides theoretical guidance for facilitating the clean and high-value utilization of coal gangue.