China Nonferrous Metallurgy

The spent carbon cathode(SCC) generated during the overhaul of aluminum reduction cell has been classified as hazardous solid waste, which contains C, F, Al and other valuable components with high recovery value,so it must be disposed of reasonably. Harmless treatment and resource utilization can reduce environmental pollution in the aluminum electrolysis industry, fostering its green and efficient circular development. This paper examines the emission patterns and resource-environmental characteristics of spent carbon cathode, with a focus on both pyrometallurgical and hydrometallurgical treatment methods. It reviews the comprehensive recycling approaches, highlighting pyrometallurgical processes such as microwave-assisted high-temperature roasting, vacuum roasting, and ultra-high-temperature graphitization, as well as hydrometallurgical methods like flotation, chemical leaching, and water leaching. Pyrometallurgical processes offer high processing capacity and simple flow but result in the combustion of significant carbon materials and flue gas emissions during roasting. In contrast, hydrometallurgical processes provide high-purity carbon recovery, large treatment capacity, and efficient resource utilization, though they face secondary pollution from managing complex acid-alkali wastewater. Future the harmless treatment of SCC should focus not only on pollution control but also on recovering valuable components and producing multi-purpose products to achieve a pollution-free, low-cost, low-energy, and high-value recycling outcome.