Abstract
The behavior of impurities in cast copper was investigated to simulate production with increased utilization of secondary sources within the framework of a circular economy. The incorporation of impurities, particularly Ni, Sn, and Sb, from recycled Cu may significantly impact the electrorefining process. In this study, commercial anodes were doped with Ni, Sn, and Sb concentrations of 2500–6500 g/t, 300–900 g/t, and 450–950 g/t, respectively. Anode concentrations of Pb and Bi were maintained at 1000 g/t and 350 g/t, respectively. As concentrations were examined at two levels, 860 or 1700 g/t, depending on the commercial anode used to create the doped samples. Electron microscopy with microprobe analysis revealed that the commercial anodes contained three predominant phases: Cu2O, (Cu,Ag)2(Se,Te), and a complex oxide phase of Cu, Pb, As, Sb, and/or Bi. Ni, the main impurity, primarily accumulated within the Cu grains, while Sn and Sb tended to form oxidized inclusions. The distribution of Ni in Cu grains was ca. 20% lower in the anodes doped at higher Ni concentrations due to the formation of nickel-bearing inclusions, such as Kupferglimmer and NiO. The doped anodes showed lower quantities of Cu2O inclusions than the commercial anodes due to the preferential formation of oxides with other impurities, including SnO2. These findings highlight potential challenges for Cu electrorefining in a circular economy, as Ni, Sb, and Sn may impact the deportment of these impurities to slimes or electrolyte and may cause copper depletion in the refining electrolyte.
Recommended Citation
A. Morales-Aragon et al., "Impurity Behavior In Cast Copper Anodes: Implications For Electrorefining In A Circular Economy," Metals, vol. 15, no. 2, article no. 113, MDPI, Feb 2025.
The definitive version is available at https://doi.org/10.3390/met15020113
Department(s)
Materials Science and Engineering
Publication Status
Open Access
Keywords and Phrases
circular economy; copper anodes; deportment; electron microscopy; nickel; tin
International Standard Serial Number (ISSN)
2075-4701
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2025 The Authors, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution 4.0 License.
Publication Date
01 Feb 2025
Comments
Universidad de Huelva, Grant None