全固废固化剂固化/稳定化赤泥路用性能研究

Red mud is a kind of general industrial solid waste produced in the production process of aluminum industry. In order to solve the problems of waste of land resources, environmental pollution and resource utilization caused by long-term stockpiling, CGFPA binder with calcium carbide residue, ground granulated blast slag, fly ash, phosphogypsum and graphene as components was used to solidify/stabilize red mud in this paper. The road performance of solidified/stabilized red mud was investigated by CBR, unconfined compressive strength, straight shear, penetration and consolidation tests. The results showed that binder could effectively improve the road performance of red mud, and the CBR value, unconfined compressive strength, and shear strength of the solidified/stabilized red mud increased, and the permeability coefficient, compression coefficient, and compression index decreased with the increase of the mixing ratio. Compared with untreated red mud, the CBR value of solidified/stabilized red mud could reach 215.8%, the unconfined compressive strength could reach 6 942.6 kPa, the cohesive force could reach 612.88 kPa, the angle of internal friction could reach 58.47°, the coefficient of permeability was reduced to 2.43×10-8cm/s, the coefficient of compression was reduced to 0.003 MPa-1, and the compression index was reduced to 0.01, all of which met its requirements as subgrade material. Meanwhile, the environmental risk of solidified/stabilized red mud as subgrade material was studied by toxic leaching test. The results showed that the leaching concentrations of Cu, Zn, Cr, Ni, As, Pb and Cd in the solidified/stabilized red mud were much lower than the specification requirements, and there was no risk of toxic leaching. The stabilization rates were 88.4%, 80.2%, 83.0%, 95.0%, 97.8%, 99.1%, and 96.6%, respectively. The results of the study could provide a theoretical basis for utilization on a large scale of red mud.