Abstract:In order to solve the technical problems of slow consolidation speed, low backfill strength, and high cement consumption of backfill slurry in Jinchanghe polymetallic mine, an orthogonal experiment was designed for the composition of a new cementitious material by testing the physical and chemical properties of multi-source solid waste around the mine. The optimal formula of the new cementitious material was obtained, which was ground granulated blast furnace slag∶ gypsum∶ lime∶ activator=81∶8∶8∶3. Based on the coupling characterization of scanning electron microscope (SEM) and midinfrared photothermal (MIP) microscopy tests, the strength growth mechanism of new cementitious material backfill was revealed. In industrial experiments, new cementitious material backfill had complete in-situ coring and good bonding properties. The consolidation strength of 38d curing age reached 3.89 MPa, which was 2.78 times of strength of the cement coring backfill. On the basis of the strength design requirements of backfill, the cementsand ratio at the bottom of the stope could be reduced to 1∶7, and the cubic filling slurry could be reduced by 28 Chinese Yuan. The research results can provide reference for the development of new cementitious materials for ultra-fine unclassified tailings.