Separation of arsenic and extraction of zinc and copper from high-arsenic copper smelting dusts by alkali leaching followed by sulfuric acid leaching

• Published in: Journal of environmental chemical engineering 2021-10, Vol.9 (5), p.105997, Article 105997
• Main Authors: Zhang, Yuhui, Feng, Xiaoyan, Qian, Long, Luan, Jin, Jin, Bingjie
• Format: Article
• Language: English
• Subjects: Alkali leaching; Arsenic; Copper smelting dusts; Separation; Sulfuric acid leaching; Valuable metals
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2021.105997

Separation of arsenic and extraction of zinc and copper from high-arsenic copper smelting dust (HACSD) is one of the difficulties in the world. A two-stage countercurrent alkali leaching followed by one-stage sulfuric acid leaching for arsenic separation and zinc and copper extraction was developed in this work. The dusts properties, metals leaching behaviors and their phase transformations in the alkali leaching and sulfuric acid leaching were explored systematically. Results indicate that >95.5% of As was successfully separated from HACSD into alkali leachate. Arsenic and metals (Zn, Pb, Bi, Sn) contents were up to 61.50 g·L−1 and as low as 0.001–0.21 g·L−1 in alkali leachate, respectively. >97.2% of Zn and >96.4% of Cu were extracted from the alkali leaching residues into sulfuric acid leachate. The sulfuric acid leaching residues were enriched with 34.16% of Pb, 8.38% of Bi and 11.54% of Sn in oxides and sulfates phases. The metals leaching behaviors, phase transformations and microstructure of metal compounds during the leaching processes were confirmed by X-ray diffraction and scanning electronic microscopy/energy dispersive spectroscopy. The proposed process offered high separation efficiency of arsenic, zinc and copper, as well as low environmental pollution. [Display omitted] •Two-stage countercurrent alkali leaching followed by one-stage of sulfuric acid leaching was developed.•Materials properties and their changes in the leaching processes were characterized.•The leaching behaviors of metals and the optimum parameters of each procedure were obtained.•>95.5% As was separated, and >97.2% Zn and >96.4% Cu were extracted.