Abstract: To achieve the resource utilization of bulk industrial solid waste and improve the sulfate resistance of mine backfill materials,this study developed a full solid-waste backfill material based on electrolytic manganese residue (EMR), phosphorous slag,and fly ash,using quicklime as an alkaline activator and triisopropanolamine (TIPA) as a modifier.The evo lution of the microstructure and the performance enhancement mechanism of the material under erosion in a 5% Na2 SO4 solu tion were systematically investigated through porosity measurements,XRD,and SEM analysis.The results indicated that sulfate attack promoted the dissolution of active silico-aluminous components,leading to the formation of hydration products such as ettringite (AFt),C-S-H,and C-A-S-H,which effectively filled pores and densified the matrix.The sample with 25% EMR content exhibited the best sulfate resistance,with the porosity decreasing from 5.77% to 4.14% after 90 days of erosion.TIPA chelated Fe3+ to enhance the dissolution of the iron phase,facilitating the formation of more stable ferric-aluminate ettringite and further optimizing the pore structure for improved long-term sulfate resistance.This study provides a theoretical and experi mental basis for the high-value utilization of EMR in sulfate-resistant mine backfill materials.

Key words: electrolytic manganese residue,mine backfilling,sulfate erosion resistance,ettringite,microstructure