Abstract:Cemented Paste Backfill (CPB) is one of the important modes of resource green mining, which can effectively control surface subsidence and ensure personnel safety. In this paper, the hydration heat test and mechanical properties test of CPB with different red mud dosages are carried out. Moreover, from the micro-scale, the red mud-based cemented paste backfill (RCPB) is analyzed to explain the reasons for the variation in compressive strength. Finally, the environmental and economic benefits of RCPB with the optimal ratio are analyzed. The test results show that the three stages of crystallization nucleation and crystal growth (NG), phase boundary reaction (I) and diffusion (D) can characterize the hydration process of RCPB. The hydration degree controls the process of the three-stage hydration (NG-I-D) of RCPB. All ratios of RCPB go through the NG-I-D stage, and the α1 of the RCPB is larger compared with the control group, indicating that the NG process is transformed into the I process only when the hydration degree is high, related to the effective water-cement ratio and nucleation of RCPB. Moreover, adding appropriate dosage of red mud can improve the performance of RCPB. Based on the strength index of backfill, the optimal ratio is C-RM16. In addition, the environmental indicators of RCPB meet the backfill requirements; the economic benefit analysis shows that RCPB with the ratio of C-RM16 can reduce the backfill cost by 5.1 ~ 9.9 Yuan/m3 and achieve considerable economic benefits.