Triple synergy by one-step reductive smelting separation for full utilization of vanadium extraction tailings: Detoxification, Fe-Cr-V wear-resistant alloy preparation and co-production of Ti-rich residue

In order to achieve the harmless and resource-efficient treatment of hazardous elements in vanadium extraction tailings, a one-step reductive smelting separation process was developed to transfer the toxic elements Cr and V into a high valuable vanadium containing ferrochrome alloy. Under the optimal parameter of basicity 1.2, C/O molar ratio 1.2, holding temperature 1550 °C and holding time 50 min, the reduction rate of Fe, V and Cr from vanadium extraction tailings reached 96.14%, 95.98%, 93.60%, respectively, with the simultaneous production of Fe-Cr-V alloy and Ti-rich slag. The hardness of the alloy was 42.27 ± 0.65 HRC and the average friction coefficient was 0.678 ± 0.001, indicating that it basically meets the standards for wear-resistant materials. Toxicity leaching test results demonstrate that the leaching concentrations of Cr and V were 0.030 and 0.013 mg/L, respectively, which were 1/32 and 1/2825 of those in the original slag. These results confirm that the tailings have been effectively rendered harmless and detoxified. Hence, this one-step reductive smelting separation method synchronously realizes metal recovery, wear-resistant alloy preparation and Ti-rich residue co-production, achieving the complete utilization of hazardous vanadium extraction tailings, and provides an effective technical approach for the resource treatment of other toxic waste residues.