Study on the stability macro- and microanalysis of tailings dam by monazite waste solidification technology

As a primary raw material for rare earth production, monazite is often associated with radioactive isotopes such as lanthanum and cerium. In order to further reduce the possibility of diffusion and enhance the stability of tailings dams, this study attempts to solidify the flowable monazite waste into solid or semisolid states by adding different types and proportions of solidifying materials. The strength characteristics of the modified soil were studied through strength tests, and the results showed that blast furnace slag exhibited the best solidification effect. Discrete element method was employed to conduct numerical calculations on the stability of tailings dams, analyzing the stability of tailings dams under different solidification schemes and slope ratios. It was found that increasing the slope ratio would lead to a decrease in the stability of tailings dams. Macroscopic and microscopic deformation characteristics of the tailings dam were analyzed: the distribution patterns of dam body velocity and displacement were generally consistent, and the simulated principal stresses were slightly larger but distributed similarly to finite element results. Microstructure analysis revealed a significant increase in contact force after solidification compared to before. This study demonstrates that employing solidification measures for monazite waste tailings dams can enhance stability, reduce environmental pollution, save cement consumption and is crucial for establishing a green ecological production system.