Analysis of the Hazardous Characteristics and Resource Utilization Direction of Solid Waste in Aluminum Electrolysis

Objective To effectively address the environmental pollution and resource waste caused by spent electrolytic aluminum residues, this paper systematically analyzes the formation process, hazardous characteristics, and resource utilization directions of spent potlining, carbon slag, and secondary aluminum dross. Method The production processes, hazard characteristics and resource utilization direction of SPL, carbon slag and aluminum ash generated during the aluminum electrolysis process were analyzed. Result The hazardous characteristics of SPL are toxicity due to the excessive content of fluoride and cyanide, and the resources in SPL mainly include carbon, fluorine, aluminum and lithium. The hazardous characteristics of carbon slag are toxicity due to excessive fluoride content, and the resources in carbon slag mainly include carbon, fluorine and aluminum. The hazardous characteristics of aluminum ash are toxicity and reactivity due to the presence of aluminum nitride, pure aluminum and fluoride. Conclusion The carbon resource in the above-mentioned hazardous wastes is mainly purified, separated and collected through flotation, acid leaching, alkali leaching and other methods. Fluorine, lithium, aluminum and other resources are generally treated through two processes: pyrometallurgical and hydrometallurgical processes. The developed products mainly include cryolite, aluminum fluoride, lithium salts, alumina, sodium aluminate and calcium aluminate etc.