Selective separation and recovery of selenium from copper anode slime by compound leaching followed by sulfate roasting

• Published in: Minerals engineering 2022-08, Vol.186, p.107749, Article 107749
• Main Authors: Zeng, Yanliang, Zou, Jianbo, Liao, Chunfa, Liu, Fupeng, Zhou, Xun
• Format: Article
• Language: English
• Subjects: Copper anode slime; Selective separation; Selenium; Separation dynamics
• ISSN: 0892-6875; 1872-9444
• DOI: 10.1016/j.mineng.2022.107749

•Selective separation and recovery of Se from copper anode slime can be achieved.•Se was effectively enriched by approximately 200% after first compound leaching.•More than 99.39 % of Se was separated by using sulfate roasting, whereas the extraction of the remaining metals in were all less than 0.5 %.•The evaporative separation process of Seis controlled by intraparticle Diffusion Control. In this research, selenium was selectively separated and recovered from copper anode slime by a hydrometallurgical-pyrometallurgy union process. In the first compound leaching process with H2SO4, HCl and NaCl media, the pre-removal of As, Sb, and Bi was achieved, and the removal efficiencies were 85 %, 83 %, and 91 %, respectively. Selenium was effectively enriched by approximately 200 % after first compound leaching. Sulfate roasting method was used to selectively separate selenium in the second stage. In this study, more than 99.39 % of selenium was separated with concentrated sulfuric acid amount to first leaching residues ratio (H2SO4/ first compound leaching residues ratio) of 0.30 mL/g at 500 °C for 25 min, which enabled selenium to be selectively separated from the other elements. The kinetics of sulfation roasting of Se-enriched residues show that the selective separation of selenium conforms to the Avrami multiphase liquid–solid region reaction, the activation energy of the reaction is 28.118 kJ/mol, and the reaction efficiencies equation is k = 3.607e-3382/T, indicating that it is internal diffusion-controlled.