Under the influence of natural rainfall, heavy metals (HMs) in Qinglong antimony tailings are easily released into surface or underground runoff, posing a great threat to the ecological environment and human health. In this study, an independently designed rainfall simulation device was used to study the effects of tailings leachate and carbonate rocks on the release behaviour and mechanism of heavy metals under rainfall activities (different rainfall intensity and intermittent rainfall). XRD shows that the characteristic minerals of tailings are quartz, gypsum, kaolinite, pyrite, fluorite and calcite, and the main antimony mineral is stibnite. The simulated rainfall shows that the release rate of HMs increases obviously with the increase of rainfall intensity, but has little effect on the leaching mechanism of HMs. The release of Sb is mainly diffusion mechanism, and the leaching of As, Fe and Mn is mainly controlled by surface leaching. Intermittent rainfall leaching significantly promoted the release of Sb and As, which increased by 109.2 μg/L and 16.6 μg/L respectively at the same time. Carbonate rocks can effectively inhibit the release of heavy metals from tailings, and make Sb have a strong correlation with the release of As, Fe and Mn. This work deepens the understanding of heavy metal leaching under various rainfall conditions and provides a useful reference for the management of open-pit tailings in karst mountain areas.

release mechanism,antimony tailings,heavy metals,leaching experiment,carbonate rocks