Abstract: In response to the frequent geological hazards occurring in goaf areas left after mineral extraction and the demand
for waste resource processing green filling materials,this study develops a phosphogypsum-based solid waste mine filling
material for goaf filling. The proposed material is intended to replace conventional cement-based binders,providing both economic
efficiency and environmental sustainability. Phosphogypsum (PG) was employed as both the cementitious binder and aggregate,
together with red mud,ground granulated blast-furnace slag,and carbide slag (CS),to develop a multi-source solid
waste synergistic system for the preparation of phosphogypsum-based solid waste mine filling material (PMFM). The workability,
mechanical strength,and environmental safety were systematically evaluated through tests on flowability,setting time,compressive
strength,leaching toxicity,and microstructure. The results show that when the PG content is 70% and the CS content is
2%,the 28-day compressive strength reaches 3. 94 MPa,and the concentrations of heavy metals in leachate are below the Class
Ⅱ groundwater standard,meeting the requirements for engineering filling. The main hydration products are C-(A)-S-H gels
and ettringite,which significantly improve the material′s compactness and solidification performance. This system enables the
resourceful utilization of multiple industrial solid wastes,providing both theoretical guidance and practical support for the development
of green mining.