Co-treatment of spent carbon anode and copper slag for reuse and the solidification of the constituent fluorine and heavy metals. (10th January 2023)

• Record Type: Journal Article
• Authors: Kuang, Biao; Zhang, Fengxia; Yu, Yong; Yang, Shiliang; Liu, Huili; Wang, Hua; Hu, Jianhang
• Is Part Of: Journal of cleaner production. Volume 383(2023)
• Publication Date: 2023-01-10
• Subjects: Spent carbon anode -- Copper slag -- Co-treatment -- Fluoride -- Heavy metals; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2022.135418
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Spent carbon anode (SCA) is a typical global hazardous solid with high risk of environmental pollution. We therefore report for the first time a novel co-treatment technology for SCA and copper slag involving clearly defined transformation paths for F, Cu, Pb and Zn. The results of the investigation showed that the F and C contents in the SCA decreased the viscosity of the slag, thereby promoting the flotation recovery of Cu, whereas the F was transformed into CaF2 . The PbSiO3 and ZnO contents in the slag were reduced to Pb(g) and Zn(g), respectively. Under optimal conditions, the solidification ratio of F reached 95.71%, and 81.50% Cu, 55.84% Pb and 36.48% Zn were recovered. The residual Cu content in the tailings decreased to 0.15 wt% after flotation. Toxicity characteristic leaching procedure test revealed that the F, Cu, Pb and Zn leaching contents were 46 mg/L, 4.58 mg/L, 2.17 mg/L and 10.71 mg/L, respectively, which are below their standard limits. The tailings can be reused as high-quality building materials with minimal environmental risk. The process herein reported presents a new and effective waste disposal approach, thus contributing to the sustainability of electrolytic aluminium and copper smelting industries. Graphical abstract: Image 1 Highlights: The co-treatment mechanism of SCA and CS was first proposed. The transformation behaviors of F, Cu, Pb and Zn were determined. Fluoride from SCA was solidified as CaF2 with a ratio of 95.71%. The residual Cu content in the tailings decreased to 0.15 wt% after co-treatment. The leaching contents were only 46 mg/L F, 4.58 mg/L Cu, 2.17 mg/L Pb and 10.71 mg/L Zn.