A sustainable approach for gold recovery from refractory source using novel BIOX-TC system

[Display omitted] This study developed a sustainable method for gold extraction from low-grade refractory ore by combining acidic biooxidation and thiocyanate (SCN) leaching (BIOX-TC) in one system to avoid neutralization and minimize the complexity of the process. Among leachant candidates, thiocya...

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Bibliographic Details
Published inJournal of industrial and engineering chemistry (Seoul, Korea) Vol. 115; pp. 209 - 218
Main Authors Azizitorghabeh, Atefeh, Mahandra, Harshit, Ramsay, Juliana, Ghahreman, Ahmad
Format Journal Article
LanguageEnglish
Published Elsevier B.V 25.11.2022
Subjects
Biooxidation
Gold leaching
Pyrite
Refractory gold
Thiocyanate
Gold leaching
Biooxidation
Pyrite
Refractory gold
Thiocyanate
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Summary:[Display omitted] This study developed a sustainable method for gold extraction from low-grade refractory ore by combining acidic biooxidation and thiocyanate (SCN) leaching (BIOX-TC) in one system to avoid neutralization and minimize the complexity of the process. Among leachant candidates, thiocyanate was proposed as a less toxic reagent for gold leaching. Furthermore, thiocyanate requires ferric iron as an oxidant for gold extraction and ferric iron can be provided by the microorganisms during biooxidation. In the first step, acidic biooxidation was done using a mixture of acidophiles including Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans resulting in 59.6% sulfur oxidation. A preliminary static incubation of Acidithiobacillus thiooxidans also improved biooxidation efficiency achieving higher sulfur oxidation of 87.8%. Following biooxidation, thiocyanate leaching using 0.2M SCN was performed under three different conditions: (1) in a separate flask with 0.01M ferric iron addition; (2) in-situ leaching, in the biooxidation flask with the mixed bacterial culture); (3) in-situ leaching in the biooxidation flask with the bacterial culture and with 0.01M additional ferric iron. It was found that in-situ thiocyanate leaching of the biooxidized ore in presence of bacterial culture and without ferric iron addition resulted in the highest gold recovery (86.9%). The biooxidation mechanism and its kinetics have been extensively discussed in this paper.
ISSN:1226-086X
DOI:10.1016/j.jiec.2022.08.002