Recent advances in hazardous gas emission mechanisms and control technologies for typical mine solid waste backfill materials

With the advancement of industrialization and the global economy, the disposal of a substantial volume of solid waste generated by mining and industrial activities has emerged as a critical issue. These bulk solid wastes occupy land, contaminate the environment, and with the progressive depletion of natural resources, the realization of their resource utilization and recycling has become an urgent matter. Solid waste backfilling mining is a key technology in green and low-carbon mining. It can not only address the problem of solid waste disposal but also manage goafs and prevent geological disasters such as ground subsidence, providing an effective approach for the disposal of bulk solid wastes and the governance of goafs. Nevertheless, when solid wastes are employed as backfill materials, they interact with the surrounding environment and may release harmful gases such as hydrogen sulfide (H₂S), sulfur dioxide (SO₂), nitrogen oxides (NO_x), ammonia (NH₃), and hydrogen fluoride (HF), which not only pollute the environment but also pose a threat to the safe production during the mining backfilling process. Therefore, how to effectively control and reduce the release of hazardous gases has become one of the key technical challenges in solid waste backfilling mining. This research focuses on typical mining backfill materials, such as coal-based solid wastes, phosphorus chemical solid wastes, and tailings sands, systematically investigates their material characteristics, as well as the mechanisms and influencing factors of harmful gas release, and summarizes the current technologies and methods for controlling harmful gases. The aim is to offer theoretical and technical support for the safe application of solid waste backfill materials, promote the rational utilization and sustainable development of solid wastes in the treatment of goafs, and provide directions and ideas for subsequent studies.