Transformation process of cathode lead structure in the recovery of waste lead paste by suspension electrolysis

• Published in: Electrochemistry communications Vol. 141; p. 107361
• Main Authors: Xie, Sen, Zhao, Lixin, Zhang, Man, Xie, Yuhong, Feng, Xin, Qin, Songyan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2022; Elsevier
• Subjects: Amorphous three-dimensional spongiform structure; Electrical conductivity; Suspension electrolysis; Waste lead paste; Suspension electrolysis; Amorphous three-dimensional spongiform structure; Electrical conductivity; Waste lead paste
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2022.107361

[Display omitted] •The cathode product obtained by suspension electrolysis of the waste lead paste is in the form of (PbO)x(PbSO4)y.•Detailed characterization of the crystal growth process and component evolution of the cathode products.•Low cathode lead precipitation due to poor conductivity of the amorphous reticulation of the cathode product. Lead is directly recovered for reuse from waste lead paste by suspension electrolysis. However, the industrial-scale application of the extracted lead is limited by the extremely low reduction rate of cathodic metallic lead during electrolysis. We used constant voltage suspension electrolysis of waste lead paste to investigate the evolution of lead product components and morphological characteristics during cathode deposition. To determine the reasons for the low reduction rate of lead in suspension electrolysis, we compared the results with those of the electrolysis of pure lead compounds. The experimental results showed that at the beginning of the suspension electrolysis, the cathode surface first deposits flower cake PbO2 primary crystals, which are then gradually reduced to PbOx flake crystals. Some flake crystals are further reduced to PbO, which is converted to PbSO4 under acidic conditions, forming a (PbO)x(PbSO4)y complex salt with PbO and finally being deposited to form an amorphous three-dimensional spongiform structure. The amorphous three-dimensional spongiform structure has poor electrical conductivity, limiting its further reduction to metallic lead. These findings provide a prospective approach for reusing waste lead paste.