Research progress on the treatment of acid coal mine drainage

The acid coal mine drainage has become one of the most difficult environmental problems in the coal industry due to its large output, wide pollution range and long duration, and unstable water quality and quantity. This paper summarizes and analyzes the pollution situation, causes and basic characteristics of acid coal mine drainage. At present, the leaching pollution caused by underground goaf water and coal gangue accumulation is the two main sources of acid coal mine drainage. At the same time, according to the different methods of producing acid drainage in large coal mines and small and medium-sized coal mines, this paper summarizes the existing treatment technologies of acid coal mine drainage from three aspects: source treatment, path blocking, and end treatment. In view of the difficulties in acid utilization and heavy metal recovery in the current acid coal mine drainage treatment, this paper puts forward the ideas of "comprehensive utilization of resources" to recover valuable substances, "treating waste with waste" acid-base neutralization, and overall comprehensive treatment.