Abstract:
As a typical multi-metal associated secondary resource, graphite tailings are rich in key strategic metals such as vanadium, iron, lithium, titanium and rare earth elements. However, the utilization rate of graphite tailings is low for a long time, and most of them are stacked. Accelerating the efficient extraction and comprehensive utilization of strategic metals in graphite tailings is of great strategic significance for ensuring national resource security and promoting the development of green mining. This paper systematically summarizes the occurrence state transformation mechanism and recovery law of different strategic metals in graphite tailings during the extraction process, and focuses on the progress of extraction technology with physical separation and chemical leaching as the core. Physical separation technology includes flotation method, magnetic separation method and gravity separation method. The flotation method can significantly improve the recovery efficiency and selectivity of vanadium, iron, lithium, titanium and other metals by optimizing the collector system and process design. Magnetic separation method utilizes the difference of magnetism to achieve efficient enrichment of vanadium and iron. The reelection rule is applicable to the recovery of titanium. Chemical leaching technology includes acid leaching, alkali leaching and roasting leaching. The acid leaching method destroys the mineral lattice by sulfuric acid, oxalic acid and other reagents to achieve efficient leaching of lithium and rare earth. The alkali leaching method uses high temperature and high concentration lye to selectively dissolve lithium or release lithium through ion exchange, which has high leaching rate and low environmental pressure. The roasting leaching method converts vanadium, iron and other metals into easy leaching forms by high temperature roasting pretreatment, and then combines acid leaching or alkali leaching to improve the recovery rate. However, the current research still faces problems such as the difficulty of dissociation caused by the complex occurrence of minerals, the lack of a multi-metal collaborative recovery system, and the risk of secondary environmental pollution. By optimizing flotation reagents, leaching processes and multi-metal synergistic recovery systems, the recovery rate of target metals is improved and the cost of reagents and energy consumption is reduced, thereby significantly improving the overall economic benefits. It shows good industrial application prospects and resource recycling value in green and efficient, resource recycling, and process integration. Future research should focus on breaking through the bottleneck of key technologies, deepening the understanding of basic theories and developing innovative processes, so as to provide theoretical and economic support for the high-value utilization of graphite tailings resources, and promote the sustainable development of mineral resources and the realization of the national “double carbon” strategic goal.