Abstract:Red mud is a kind of solid waste in the production process of aluminum industry. In order to solve the waste of land resources and environmental pollution and resource utilization problems caused by long-term stockpiling, this paper adopts CGFPA curing agent with calcium carbide residue, ground granulated blast furnace slag, fly ash, phosphogypsum and graphene as components for the harmless treatment of red mud. Tests of unconfined compressive strength, acidity and alkalinity, and toxicity leaching were used to study the effects of curing agent dosing, total initial moisture content, and curing age on the strength properties, acidity and alkalinity, and toxicity leaching properties of solidified/stabilized red mud. The results show that the unconfined compressive strength of solidified/stabilized red mud increases and then decreases, while the pollutant concentration decreases and then increases, there exists an optimal total water content ratio (the ratio of the total initial water content to the liquid limit of the red mud) with the maximum strength and the lowest pollutant concentration, and that the optimal water content ratio increases linearly with the mixing ratio of the binder. The optimal water content ratios are 1.0, 1.2, 1.3, and 1.4 for 15%, 20%, 25%, and 30% mixing ratios, respectively, corresponding to the optimal total initial water content of 37.8%, 45.4%, 49.1%, and 52.9%, respectively. The pH value of the solidified/stabilized red mud decreased with the increase of the curing age, and was lower than 9.5 after 90ds; it decreased with the increase of the total water content ratio, and gradually tended to be stabilized. In addition, the concentration of pollutants in the solidified/stabilized red mud decreased gradually with the increase of binder mixing ratio, and the removal rate of seven pollutants could reach more than 80% when the mixing ratio was 30% and the total water content ratio was 1.4. The research results have certain practical significance for the harmless treatment and resource utilization of red mud.