###### Abstract
[10] investigated the effect of exogenous sulfate erosion on the mechanical behavior and properties of CGB, and the results showed that the sulfate concentration is a hydration product formation important factor which directly affects the macroscopic behavior and volume of CGB before and after damage. The studies mentioned above indicate that chemical ion erosion impacts the microstructure of CGB, which leads to a change in the mechanical response. Therefore, it is crucial to investigate how chemical erosion affects the stress threshold of CGB crack development. However, these studies focus more on examining the changes in the macroscopic mechanical properties of CGB due to chemical erosion rather than on studying its fracture behavior. The acoustic emission (AE) signal can reflect both the material's internal changes and the material's mechanical response under loading [17]. The acoustic emission technique is helpful in analyzing the internal fracture process of chemically eroded CGB under loading. [PERSON] et al. [18] studied the acoustic emission characteristics of backfill with different ash-to-sand ratios under different loading modes. They found that the split specimens' acoustic emission activity patterns were the same as those under uniaxial compression. During the splitting test, the filled specimens did not exhibit any acoustic emission activity and behaved calmly before the peak stress period. When the stress reached the peak, the acoustic emission activity level became abnormally high and reached the maximum value. [PERSON] et al. [19] investigated the acoustic emission characteristics of colluvial ending sands under different loading rates. They found that the distribution of ringing counts during the loading process had a regular peak spacing. The cumulative number of ringing counts also showed a \"stepwise\" growth trend and eventually stabilized. [PERSON] et al. [20] studied the effect of aggregate gradation on the acoustic properties of compressed cemented mounds. They found that the acoustic emission signal activity was positively correlated with the Talbot index of cemented mound aggregates. These findings contribute to a better understanding of the AE characteristics of CGB during loading. However, most previous studies have focused on the acoustic emission characteristics of filled bodies with different material ratios or loading methods. The acoustic emission characteristics of CGB loaded by chemical ion erosion have not been thoroughly investigated. Considering the importance of the effect of chemical erosion on the performance of cemented gangue backfill, this paper attempts to investigate the acoustic, mechanical, and physical changes in CGB due to the erosion time of chemical ions. First, fresh CGB was prepared and processed into standard samples. The samples were immersed in the same pH solution for different times using the laboratory accelerated corrosion test method. Then, we conducted a uniaxial compression test, recorded the acoustic emission signals, and investigated the effect of chemical ion erosion on the damage characteristics of CGB during loading using acoustic emission signals. Finally, the microstructure and chemical composition changes in the eroded backfill were analyzed by SEM.