Recovery of metallic copper from waste printed circuit boards via H3NO3S-NaCl-H2O2 leaching system. (10th July 2022)

• Record Type: Journal Article
• Authors: Guo, Shulian; He, Jingfeng; Zhu, Lingtao; Chen, Hao; Zhou, Kui; Xu, Jiang; Chen, Zengqiang
• Is Part Of: Journal of cleaner production. Volume 357(2022)
• Publication Date: 2022-07-10
• Subjects: Waste printed circuit boards -- Sulfamic acid -- H3NO3S-NaCl-H2O2 -- Thermodynamic analysis -- Kinetic analysis -- Leaching rate; 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.2022.131732
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: In this study, sulfamic acid (H3 NO3 S) was used to leach Cu from waste printed circuit boards (WPCBs) by using hydrogen peroxide as strong oxidant and NaCl as additive. The effects of NaCl concentration, sulfamic acid concentration, hydrogen peroxide concentration, temperature and reaction time on copper leaching were investigated. Under the optimum operated conditions, the leaching rate of copper was 91.24%. The thermodynamic analysis predicted that the dissolution of copper was promoted by adding NaCl to the mixed leaching solution of H3 NO3 S and H2 O2 . Kinetic analysis shows that the leaching process was controlled by solid film diffusion with an apparent activation energy of 7.78 kJ/mol. Through the analysis of zoom stereo microscope and X-ray diffraction (XRD), copper failed to completely leach because it was wrapped by insoluble substances, which prevented further leaching of copper. The leaching of copper from WPCBs with H3 NO3 S-NaCl-H2 O2 system was an efficient and environmentally friendly method. Based on this study, a new process for recovering WPCBs is proposed. Highlights: The addition of appropriate amount of NaCl could promote the leaching of copper. H3 NO3 S-NaCl-H2 O2 leaching system is an effective method to recover copper. The leaching process of copper was controlled by solid film diffusion process. The mechanism of copper leaching in H3 NO3 S-NaCl-H2 O2 system was explained.