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The effect of silver on the acidic ferric sulfate leaching of primary copper sulfides under recycle solution conditions observed in heap leaching. Part 4: Semiconductor behaviour

Tapera, T. and Nikoloski, A.N. (2019) The effect of silver on the acidic ferric sulfate leaching of primary copper sulfides under recycle solution conditions observed in heap leaching. Part 4: Semiconductor behaviour. Hydrometallurgy, 186 . pp. 50-57.

Link to Published Version: https://doi.org/10.1016/j.hydromet.2019.03.016
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Abstract

The semiconductor properties of chalcopyrite during leaching in sulfate solutions in the presence of silver have been investigated. A combination of Mott-Schottky plots and potentiodynamic polarisation was used to determine the transformations of the chalcopyrite surface as the potential was changed between +200 mV (SHE) and 1200 mV (SHE). The tests were carried out at 25 °C and 50 °C. The solutions used were 0.2 M and 0.5 M H2SO4 in the presence of 100 ppm Ag+ and then in the absence of Ag+. The semiconductor behaviour of chalcopyrite was different depending on the presence or absence of Ag. At 25 °C, two surface layers formed between 500 mV (SHE) and 1000 mV (SHE) in both the 0.2 M and 0.5 M acid solutions. The presence of Ag in both these solutions shifted the potentials at which the surface phases formed to more positive potentials. In the presence of Ag at 50 °C, there was formation of successive surface layers at potentials between 850 mV (SHE) and 1000 mV (SHE). It was concluded that Ag had a significant influence on the semiconductor properties of the chalcopyrite surface. The Ag present on the surface as metallic Ag acts as surface states and provides a path for electrons to tunnel or hop from the valence band to the conduction band.

Item Type: Journal Article
Murdoch Affiliation: College of Science, Health, Engineering and Education
Publisher: Elsevier BV
Copyright: © 2019 Published by Elsevier B.V.
URI: http://researchrepository.murdoch.edu.au/id/eprint/44959
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