Kinetics of chalcocite leaching in oxygenated alkaline glycine solutions

© 2018 Elsevier B.V. Naturally occurring chalcocite (Cu2S) was leached with oxygenated alkaline glycine solutions. The influence of glycine concentration, stirring speed, particle size, dissolved oxygen concentration and temperature on the copper dissolution rate were evaluated. Under all conditions...

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Main Authors: Tanda, B., Eksteen, Jacques, Oraby, Elsayed
Format: Journal Article
Published: Elsevier 2018
Online Access:http://hdl.handle.net/20.500.11937/68834
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author Tanda, B.
Eksteen, Jacques
Oraby, Elsayed
author_facet Tanda, B.
Eksteen, Jacques
Oraby, Elsayed
author_sort Tanda, B.
building Curtin Institutional Repository
collection Online Access
description © 2018 Elsevier B.V. Naturally occurring chalcocite (Cu2S) was leached with oxygenated alkaline glycine solutions. The influence of glycine concentration, stirring speed, particle size, dissolved oxygen concentration and temperature on the copper dissolution rate were evaluated. Under all conditions, the copper leach rate was very rapid in the first 6 h of leaching after which significant slower rates were recorded. The influence of fine grinding P100–20 µm was remarkable with up to 78% Cu extracted over 6 h of leaching as compared to just 40% for 38–53 µm size fraction under the same conditions. SEM-EDS and XPS analysis of the leach residue confirmed the presence of covellite (CuS) on the particle surfaces. It appears that chalcocite leaching in oxygenated alkaline glycine solution occurs in two stages. The first stage is fast and involves the conversion of chalcocite into cupric ions and covellite while in the second stage, the formed covellite slowly converts to cupric ions and sulfate ions. Kinetic analysis using the shrinking core model of both the first and second stages indicates that the reactions appear to be controlled by diffusion through the product layer with calculated apparent activation energies being 25.kJ/mol (1st stage) and 108 kJ/mol (2nd stage).
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spelling curtin-20.500.11937-688342018-06-29T12:35:59Z Kinetics of chalcocite leaching in oxygenated alkaline glycine solutions Tanda, B. Eksteen, Jacques Oraby, Elsayed © 2018 Elsevier B.V. Naturally occurring chalcocite (Cu2S) was leached with oxygenated alkaline glycine solutions. The influence of glycine concentration, stirring speed, particle size, dissolved oxygen concentration and temperature on the copper dissolution rate were evaluated. Under all conditions, the copper leach rate was very rapid in the first 6 h of leaching after which significant slower rates were recorded. The influence of fine grinding P100–20 µm was remarkable with up to 78% Cu extracted over 6 h of leaching as compared to just 40% for 38–53 µm size fraction under the same conditions. SEM-EDS and XPS analysis of the leach residue confirmed the presence of covellite (CuS) on the particle surfaces. It appears that chalcocite leaching in oxygenated alkaline glycine solution occurs in two stages. The first stage is fast and involves the conversion of chalcocite into cupric ions and covellite while in the second stage, the formed covellite slowly converts to cupric ions and sulfate ions. Kinetic analysis using the shrinking core model of both the first and second stages indicates that the reactions appear to be controlled by diffusion through the product layer with calculated apparent activation energies being 25.kJ/mol (1st stage) and 108 kJ/mol (2nd stage). 2018 Journal Article http://hdl.handle.net/20.500.11937/68834 10.1016/j.hydromet.2018.05.005 Elsevier restricted
spellingShingle Tanda, B.
Eksteen, Jacques
Oraby, Elsayed
Kinetics of chalcocite leaching in oxygenated alkaline glycine solutions
title Kinetics of chalcocite leaching in oxygenated alkaline glycine solutions
title_full Kinetics of chalcocite leaching in oxygenated alkaline glycine solutions
title_fullStr Kinetics of chalcocite leaching in oxygenated alkaline glycine solutions
title_full_unstemmed Kinetics of chalcocite leaching in oxygenated alkaline glycine solutions
title_short Kinetics of chalcocite leaching in oxygenated alkaline glycine solutions
title_sort kinetics of chalcocite leaching in oxygenated alkaline glycine solutions
url http://hdl.handle.net/20.500.11937/68834