Research on the preparation of prebaked anodes using regenerated graphite from spent carbon cathodes:

• Regenerated graphite was utilized for blending to prepare prebaked anodes. • Blended anodes with qualified performance were prepared at low blending ratios. • The limitations of high-dosage utilization of regenerated graphite were revealed. • Wettability regulation was crucial for the recycling of regenerated graphite. • The value-added utilization of carbonaceous hazardous waste was achieved. Spent carbon cathodes (SCCs) contain substantial graphite resources and have considerable potential for value-added utilization. However, no value-added utilization pathways have been explored for regenerated graphite extracted from SCCs. In this work, multistage chemical leaching was employed to extract graphite resources from SCC. Multiple detection techniques were used to explore the differences in utilization properties between regenerated graphite and initial materials. Subsequently, regenerated graphite was used in situ to prepare prebaked anodes for aluminum electrolysis. The blending form and ratio of recycled graphite were sequentially optimized. The feasibility of utilizing regenerated graphite for the value-added preparation of anodes was evaluated based on attribute differences and anode performance metrics. Results demonstrated that regenerated graphite exhibited substantial differences compared with the initial material in terms of basic, application, and microscopic attributes. The rise in non-carbon impurity content and the deterioration of coal tar pitch wettability have significantly impaired the performance of prebaked anodes. Furthermore, the degree of graphitization exhibits a positive correlation with the mechanical properties of these anodes. Compared with calcined petroleum coke (CPC), regenerated graphite was more suitable for replacing recycled anode butts in the preparation of prebaked anodes. The deep purification and wettability control strategy for regenerated graphite is an essential technical approach to facilitate the replacement of CPC. The proposed value-added utilization strategy for regenerated graphite offers a viable, scalable solution for the disposal and resource recovery of SCCs.