Abstract:The harmless resource utilization of spent carbon cathodes has become an environmental problem restricting the green and sustainable development of aluminum industry. Based on the industrial composition and leaching toxicity of spent carbon cathodes with different aggregate particle sizes, effects of aggregate particle size and roasting temperature on high-temperature roasting treatment of spent carbon cathodes were explored. The results show that with the increase of aggregate particle size and roasting temperature, the carbon content of recovered carbon material rises continuously and soluble fluoride content drops greatly. Under the optimal high-temperature roasting parameters, carbon content of the recovered carbon material rises from 65.21% to 94.52%, and the fluorine ion concentration drops from 4 018.55 mg/L to 7.63 mg/L. Meanwhile, the condensed gas product was cured by chemical precipitation method and extracted high purity CaF2 product to avoid secondary pollution of high concentration fluorine-containing flue gas. It is feasible to treat spent carbon cathodes of aluminum electrolysis via high-temperature roasting.