Abstract:In the purification processes of strategic new energy minerals such as graphite and quartz, substantial amounts of fluoride-containing wastewater are typically generated. To address the environmental pollution caused by fluoride discharge, this study simulated the treatment of fluoride-containing wastewater (500 mg/L F?) using a coagulation-sedimentation method. The effects of polyacrylamide (PAM) on fluoride removal efficiency were systematically investigated, with a focus on optimizing parameters including PAM type, molecular weight, dosage, pH, and coagulation time. The characteristics of the post-coagulation precipitates were analyzed via XRD and SEM-EDS, and the flotation behavior of CaF? crystallization was explored to enhance its recovery potential. The results revealed that under optimal conditions—nonionic PAM with a molecular weight of 7 million, a dosage of 40 mg/L, pH 7, and a coagulation time of 60 min—the turbidity of the treated wastewater was reduced to 1.979 NTU, and the residual F? concentration decreased to 4.734 mg/L, meeting industrial fluoride emission standards. The primary component of the coagulated precipitates was identified as CaF?, exhibiting macroscopic dense white flocs and microscopic spherical crystalline aggregates. During flotation tests, a CaF? recovery rate of 91.94% was achieved at a sodium oleate (NaOL) dosage of 80 mg/L. Remarkably, the NaOL consumption was halved compared to systems without PAM addition, demonstrating significant efficiency in resource recovery. This approach not only improves the recycling rate of CaF? but also supports the sustainable utilization of strategic non-metallic mineral resources, such as fluorite, thereby contributing to national resource security and environmental protection.